Contract Source Code:

pragma solidity ^0.5.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
  /**
   * @dev Returns the addition of two unsigned integers, reverting on
   * overflow.
   *
   * Counterpart to Solidity's `+` operator.
   *
   * Requirements:
   * - Addition cannot overflow.
   */
  function add(uint256 a, uint256 b) internal pure returns (uint256) {
    uint256 c = a + b;
    require(c >= a, 'SafeMath: addition overflow');

    return c;
  }

  /**
   * @dev Returns the subtraction of two unsigned integers, reverting on
   * overflow (when the result is negative).
   *
   * Counterpart to Solidity's `-` operator.
   *
   * Requirements:
   * - Subtraction cannot overflow.
   */
  function sub(uint256 a, uint256 b) internal pure returns (uint256) {
    require(b <= a, 'SafeMath: subtraction overflow');
    uint256 c = a - b;

    return c;
  }

  /**
   * @dev Returns the multiplication of two unsigned integers, reverting on
   * overflow.
   *
   * Counterpart to Solidity's `*` operator.
   *
   * Requirements:
   * - Multiplication cannot overflow.
   */
  function mul(uint256 a, uint256 b) internal pure returns (uint256) {
    // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
    // benefit is lost if 'b' is also tested.
    // See: https://github.com/OpenZeppelin/openzeppelin-solidity/pull/522
    if (a == 0) {
      return 0;
    }

    uint256 c = a * b;
    require(c / a == b, 'SafeMath: multiplication overflow');

    return c;
  }

  /**
   * @dev Returns the integer division of two unsigned integers. Reverts on
   * division by zero. The result is rounded towards zero.
   *
   * Counterpart to Solidity's `/` operator. Note: this function uses a
   * `revert` opcode (which leaves remaining gas untouched) while Solidity
   * uses an invalid opcode to revert (consuming all remaining gas).
   *
   * Requirements:
   * - The divisor cannot be zero.
   */
  function div(uint256 a, uint256 b) internal pure returns (uint256) {
    // Solidity only automatically asserts when dividing by 0
    require(b > 0, 'SafeMath: division by zero');
    uint256 c = a / b;
    // assert(a == b * c + a % b); // There is no case in which this doesn't hold

    return c;
  }

  /**
   * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
   * Reverts when dividing by zero.
   *
   * Counterpart to Solidity's `%` operator. This function uses a `revert`
   * opcode (which leaves remaining gas untouched) while Solidity uses an
   * invalid opcode to revert (consuming all remaining gas).
   *
   * Requirements:
   * - The divisor cannot be zero.
   */
  function mod(uint256 a, uint256 b) internal pure returns (uint256) {
    require(b != 0, 'SafeMath: modulo by zero');
    return a % b;
  }
}

/**
 * @title WadRayMath library
 * @author Aave
 * @dev Provides mul and div function for wads (decimal numbers with 18 digits precision) and rays (decimals with 27 digits)
 **/

library WadRayMath {
  using SafeMath for uint256;

  uint256 internal constant WAD = 1e18;
  uint256 internal constant halfWAD = WAD / 2;

  uint256 internal constant RAY = 1e27;
  uint256 internal constant halfRAY = RAY / 2;

  uint256 internal constant WAD_RAY_RATIO = 1e9;

  /**
   * @return one ray, 1e27
   **/
  function ray() internal pure returns (uint256) {
    return RAY;
  }

  /**
   * @return one wad, 1e18
   **/

  function wad() internal pure returns (uint256) {
    return WAD;
  }

  /**
   * @return half ray, 1e27/2
   **/
  function halfRay() internal pure returns (uint256) {
    return halfRAY;
  }

  /**
   * @return half ray, 1e18/2
   **/
  function halfWad() internal pure returns (uint256) {
    return halfWAD;
  }

  /**
   * @dev multiplies two wad, rounding half up to the nearest wad
   * @param a wad
   * @param b wad
   * @return the result of a*b, in wad
   **/
  function wadMul(uint256 a, uint256 b) internal pure returns (uint256) {
    return halfWAD.add(a.mul(b)).div(WAD);
  }

  /**
   * @dev divides two wad, rounding half up to the nearest wad
   * @param a wad
   * @param b wad
   * @return the result of a/b, in wad
   **/
  function wadDiv(uint256 a, uint256 b) internal pure returns (uint256) {
    uint256 halfB = b / 2;

    return halfB.add(a.mul(WAD)).div(b);
  }

  /**
   * @dev multiplies two ray, rounding half up to the nearest ray
   * @param a ray
   * @param b ray
   * @return the result of a*b, in ray
   **/
  function rayMul(uint256 a, uint256 b) internal pure returns (uint256) {
    return halfRAY.add(a.mul(b)).div(RAY);
  }

  /**
   * @dev divides two ray, rounding half up to the nearest ray
   * @param a ray
   * @param b ray
   * @return the result of a/b, in ray
   **/
  function rayDiv(uint256 a, uint256 b) internal pure returns (uint256) {
    uint256 halfB = b / 2;

    return halfB.add(a.mul(RAY)).div(b);
  }

  /**
   * @dev casts ray down to wad
   * @param a ray
   * @return a casted to wad, rounded half up to the nearest wad
   **/
  function rayToWad(uint256 a) internal pure returns (uint256) {
    uint256 halfRatio = WAD_RAY_RATIO / 2;

    return halfRatio.add(a).div(WAD_RAY_RATIO);
  }

  /**
   * @dev convert wad up to ray
   * @param a wad
   * @return a converted in ray
   **/
  function wadToRay(uint256 a) internal pure returns (uint256) {
    return a.mul(WAD_RAY_RATIO);
  }

  /**
   * @dev calculates base^exp. The code uses the ModExp precompile
   * @return base^exp, in ray
   */
  //solium-disable-next-line
  function rayPow(uint256 x, uint256 n) internal pure returns (uint256 z) {
    z = n % 2 != 0 ? x : RAY;

    for (n /= 2; n != 0; n /= 2) {
      x = rayMul(x, x);

      if (n % 2 != 0) {
        z = rayMul(z, x);
      }
    }
  }
}

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the `nonReentrant` modifier
 * available, which can be aplied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 */
contract ReentrancyGuard {
  /// @dev counter to allow mutex lock with only one SSTORE operation
  uint256 private _guardCounter;

  constructor() internal {
    // The counter starts at one to prevent changing it from zero to a non-zero
    // value, which is a more expensive operation.
    _guardCounter = 1;
  }

  /**
   * @dev Prevents a contract from calling itself, directly or indirectly.
   * Calling a `nonReentrant` function from another `nonReentrant`
   * function is not supported. It is possible to prevent this from happening
   * by making the `nonReentrant` function external, and make it call a
   * `private` function that does the actual work.
   */
  modifier nonReentrant() {
    _guardCounter += 1;
    uint256 localCounter = _guardCounter;
    _;
    require(localCounter == _guardCounter, 'ReentrancyGuard: reentrant call');
  }
}

/**
 * @dev Collection of functions related to the address type,
 */
library Address {
  /**
   * @dev Returns true if `account` is a contract.
   *
   * This test is non-exhaustive, and there may be false-negatives: during the
   * execution of a contract's constructor, its address will be reported as
   * not containing a contract.
   *
   * > It is unsafe to assume that an address for which this function returns
   * false is an externally-owned account (EOA) and not a contract.
   */
  function isContract(address account) internal view returns (bool) {
    // This method relies in extcodesize, which returns 0 for contracts in
    // construction, since the code is only stored at the end of the
    // constructor execution.

    uint256 size;
    // solhint-disable-next-line no-inline-assembly
    assembly {
      size := extcodesize(account)
    }
    return size > 0;
  }
}

/**
 * @dev Interface of the ERC20 standard as defined in the EIP. Does not include
 * the optional functions; to access them see `ERC20Detailed`.
 */
interface IERC20 {
  /**
   * @dev Returns the amount of tokens in existence.
   */
  function totalSupply() external view returns (uint256);

  /**
   * @dev Returns the amount of tokens owned by `account`.
   */
  function balanceOf(address account) external view returns (uint256);

  /**
   * @dev Moves `amount` tokens from the caller's account to `recipient`.
   *
   * Returns a boolean value indicating whether the operation succeeded.
   *
   * Emits a `Transfer` event.
   */
  function transfer(address recipient, uint256 amount) external returns (bool);

  /**
   * @dev Returns the remaining number of tokens that `spender` will be
   * allowed to spend on behalf of `owner` through `transferFrom`. This is
   * zero by default.
   *
   * This value changes when `approve` or `transferFrom` are called.
   */
  function allowance(address owner, address spender) external view returns (uint256);

  /**
   * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
   *
   * Returns a boolean value indicating whether the operation succeeded.
   *
   * > Beware that changing an allowance with this method brings the risk
   * that someone may use both the old and the new allowance by unfortunate
   * transaction ordering. One possible solution to mitigate this race
   * condition is to first reduce the spender's allowance to 0 and set the
   * desired value afterwards:
   * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
   *
   * Emits an `Approval` event.
   */
  function approve(address spender, uint256 amount) external returns (bool);

  /**
   * @dev Moves `amount` tokens from `sender` to `recipient` using the
   * allowance mechanism. `amount` is then deducted from the caller's
   * allowance.
   *
   * Returns a boolean value indicating whether the operation succeeded.
   *
   * Emits a `Transfer` event.
   */
  function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

  /**
   * @dev Emitted when `value` tokens are moved from one account (`from`) to
   * another (`to`).
   *
   * Note that `value` may be zero.
   */
  event Transfer(address indexed from, address indexed to, uint256 value);

  /**
   * @dev Emitted when the allowance of a `spender` for an `owner` is set by
   * a call to `approve`. `value` is the new allowance.
   */
  event Approval(address indexed owner, address indexed spender, uint256 value);
}

/**
 * @dev Implementation of the `IERC20` interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using `_mint`.
 * For a generic mechanism see `ERC20Mintable`.
 *
 * *For a detailed writeup see our guide [How to implement supply
 * mechanisms](https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226).*
 *
 * We have followed general OpenZeppelin guidelines: functions revert instead
 * of returning `false` on failure. This behavior is nonetheless conventional
 * and does not conflict with the expectations of ERC20 applications.
 *
 * Additionally, an `Approval` event is emitted on calls to `transferFrom`.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard `decreaseAllowance` and `increaseAllowance`
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See `IERC20.approve`.
 */
contract ERC20 is IERC20 {
  using SafeMath for uint256;

  mapping(address => uint256) private _balances;

  mapping(address => mapping(address => uint256)) private _allowances;

  uint256 private _totalSupply;

  /**
   * @dev See `IERC20.totalSupply`.
   */
  function totalSupply() public view returns (uint256) {
    return _totalSupply;
  }

  /**
   * @dev See `IERC20.balanceOf`.
   */
  function balanceOf(address account) public view returns (uint256) {
    return _balances[account];
  }

  /**
   * @dev See `IERC20.transfer`.
   *
   * Requirements:
   *
   * - `recipient` cannot be the zero address.
   * - the caller must have a balance of at least `amount`.
   */
  function transfer(address recipient, uint256 amount) public returns (bool) {
    _transfer(msg.sender, recipient, amount);
    return true;
  }

  /**
   * @dev See `IERC20.allowance`.
   */
  function allowance(address owner, address spender) public view returns (uint256) {
    return _allowances[owner][spender];
  }

  /**
   * @dev See `IERC20.approve`.
   *
   * Requirements:
   *
   * - `spender` cannot be the zero address.
   */
  function approve(address spender, uint256 value) public returns (bool) {
    _approve(msg.sender, spender, value);
    return true;
  }

  /**
   * @dev See `IERC20.transferFrom`.
   *
   * Emits an `Approval` event indicating the updated allowance. This is not
   * required by the EIP. See the note at the beginning of `ERC20`;
   *
   * Requirements:
   * - `sender` and `recipient` cannot be the zero address.
   * - `sender` must have a balance of at least `value`.
   * - the caller must have allowance for `sender`'s tokens of at least
   * `amount`.
   */
  function transferFrom(address sender, address recipient, uint256 amount) public returns (bool) {
    _transfer(sender, recipient, amount);
    _approve(sender, msg.sender, _allowances[sender][msg.sender].sub(amount));
    return true;
  }

  /**
   * @dev Atomically increases the allowance granted to `spender` by the caller.
   *
   * This is an alternative to `approve` that can be used as a mitigation for
   * problems described in `IERC20.approve`.
   *
   * Emits an `Approval` event indicating the updated allowance.
   *
   * Requirements:
   *
   * - `spender` cannot be the zero address.
   */
  function increaseAllowance(address spender, uint256 addedValue) public returns (bool) {
    _approve(msg.sender, spender, _allowances[msg.sender][spender].add(addedValue));
    return true;
  }

  /**
   * @dev Atomically decreases the allowance granted to `spender` by the caller.
   *
   * This is an alternative to `approve` that can be used as a mitigation for
   * problems described in `IERC20.approve`.
   *
   * Emits an `Approval` event indicating the updated allowance.
   *
   * Requirements:
   *
   * - `spender` cannot be the zero address.
   * - `spender` must have allowance for the caller of at least
   * `subtractedValue`.
   */
  function decreaseAllowance(address spender, uint256 subtractedValue) public returns (bool) {
    _approve(msg.sender, spender, _allowances[msg.sender][spender].sub(subtractedValue));
    return true;
  }

  /**
   * @dev Moves tokens `amount` from `sender` to `recipient`.
   *
   * This is internal function is equivalent to `transfer`, and can be used to
   * e.g. implement automatic token fees, slashing mechanisms, etc.
   *
   * Emits a `Transfer` event.
   *
   * Requirements:
   *
   * - `sender` cannot be the zero address.
   * - `recipient` cannot be the zero address.
   * - `sender` must have a balance of at least `amount`.
   */
  function _transfer(address sender, address recipient, uint256 amount) internal {
    require(sender != address(0), 'ERC20: transfer from the zero address');
    require(recipient != address(0), 'ERC20: transfer to the zero address');

    _balances[sender] = _balances[sender].sub(amount);
    _balances[recipient] = _balances[recipient].add(amount);
    emit Transfer(sender, recipient, amount);
  }

  /** @dev Creates `amount` tokens and assigns them to `account`, increasing
   * the total supply.
   *
   * Emits a `Transfer` event with `from` set to the zero address.
   *
   * Requirements
   *
   * - `to` cannot be the zero address.
   */
  function _mint(address account, uint256 amount) internal {
    require(account != address(0), 'ERC20: mint to the zero address');

    _totalSupply = _totalSupply.add(amount);
    _balances[account] = _balances[account].add(amount);
    emit Transfer(address(0), account, amount);
  }

  /**
   * @dev Destoys `amount` tokens from `account`, reducing the
   * total supply.
   *
   * Emits a `Transfer` event with `to` set to the zero address.
   *
   * Requirements
   *
   * - `account` cannot be the zero address.
   * - `account` must have at least `amount` tokens.
   */
  function _burn(address account, uint256 value) internal {
    require(account != address(0), 'ERC20: burn from the zero address');

    _totalSupply = _totalSupply.sub(value);
    _balances[account] = _balances[account].sub(value);
    emit Transfer(account, address(0), value);
  }

  /**
   * @dev Sets `amount` as the allowance of `spender` over the `owner`s tokens.
   *
   * This is internal function is equivalent to `approve`, and can be used to
   * e.g. set automatic allowances for certain subsystems, etc.
   *
   * Emits an `Approval` event.
   *
   * Requirements:
   *
   * - `owner` cannot be the zero address.
   * - `spender` cannot be the zero address.
   */
  function _approve(address owner, address spender, uint256 value) internal {
    require(owner != address(0), 'ERC20: approve from the zero address');
    require(spender != address(0), 'ERC20: approve to the zero address');

    _allowances[owner][spender] = value;
    emit Approval(owner, spender, value);
  }

  /**
   * @dev Destoys `amount` tokens from `account`.`amount` is then deducted
   * from the caller's allowance.
   *
   * See `_burn` and `_approve`.
   */
  function _burnFrom(address account, uint256 amount) internal {
    _burn(account, amount);
    _approve(account, msg.sender, _allowances[account][msg.sender].sub(amount));
  }
}

/**
 * @dev Optional functions from the ERC20 standard.
 */
contract ERC20Detailed is IERC20 {
  string private _name;
  string private _symbol;
  uint8 private _decimals;

  /**
   * @dev Sets the values for `name`, `symbol`, and `decimals`. All three of
   * these values are immutable: they can only be set once during
   * construction.
   */
  constructor(string memory name, string memory symbol, uint8 decimals) public {
    _name = name;
    _symbol = symbol;
    _decimals = decimals;
  }

  /**
   * @dev Returns the name of the token.
   */
  function name() public view returns (string memory) {
    return _name;
  }

  /**
   * @dev Returns the symbol of the token, usually a shorter version of the
   * name.
   */
  function symbol() public view returns (string memory) {
    return _symbol;
  }

  /**
   * @dev Returns the number of decimals used to get its user representation.
   * For example, if `decimals` equals `2`, a balance of `505` tokens should
   * be displayed to a user as `5,05` (`505 / 10 ** 2`).
   *
   * Tokens usually opt for a value of 18, imitating the relationship between
   * Ether and Wei.
   *
   * > Note that this information is only used for _display_ purposes: it in
   * no way affects any of the arithmetic of the contract, including
   * `IERC20.balanceOf` and `IERC20.transfer`.
   */
  function decimals() public view returns (uint8) {
    return _decimals;
  }
}

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for ERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
  using SafeMath for uint256;
  using Address for address;

  function safeTransfer(IERC20 token, address to, uint256 value) internal {
    callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
  }

  function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
    callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
  }

  function safeApprove(IERC20 token, address spender, uint256 value) internal {
    // safeApprove should only be called when setting an initial allowance,
    // or when resetting it to zero. To increase and decrease it, use
    // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
    // solhint-disable-next-line max-line-length
    require(
      (value == 0) || (token.allowance(address(this), spender) == 0),
      'SafeERC20: approve from non-zero to non-zero allowance'
    );
    callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
  }

  function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
    uint256 newAllowance = token.allowance(address(this), spender).add(value);
    callOptionalReturn(
      token,
      abi.encodeWithSelector(token.approve.selector, spender, newAllowance)
    );
  }

  function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
    uint256 newAllowance = token.allowance(address(this), spender).sub(value);
    callOptionalReturn(
      token,
      abi.encodeWithSelector(token.approve.selector, spender, newAllowance)
    );
  }

  /**
   * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
   * on the return value: the return value is optional (but if data is returned, it must not be false).
   * @param token The token targeted by the call.
   * @param data The call data (encoded using abi.encode or one of its variants).
   */
  function callOptionalReturn(IERC20 token, bytes memory data) private {
    // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
    // we're implementing it ourselves.

    // A Solidity high level call has three parts:
    //  1. The target address is checked to verify it contains contract code
    //  2. The call itself is made, and success asserted
    //  3. The return value is decoded, which in turn checks the size of the returned data.
    // solhint-disable-next-line max-line-length
    require(address(token).isContract(), 'SafeERC20: call to non-contract');

    // solhint-disable-next-line avoid-low-level-calls
    (bool success, bytes memory returndata) = address(token).call(data);
    require(success, 'SafeERC20: low-level call failed');

    if (returndata.length > 0) {
      // Return data is optional
      // solhint-disable-next-line max-line-length
      require(abi.decode(returndata, (bool)), 'SafeERC20: ERC20 operation did not succeed');
    }
  }
}

/**
 * @title VersionedInitializable
 *
 * @dev Helper contract to support initializer functions. To use it, replace
 * the constructor with a function that has the `initializer` modifier.
 * WARNING: Unlike constructors, initializer functions must be manually
 * invoked. This applies both to deploying an Initializable contract, as well
 * as extending an Initializable contract via inheritance.
 * WARNING: When used with inheritance, manual care must be taken to not invoke
 * a parent initializer twice, or ensure that all initializers are idempotent,
 * because this is not dealt with automatically as with constructors.
 *
 * @author Aave, inspired by the OpenZeppelin Initializable contract
 */
contract VersionedInitializable {
  /**
   * @dev Indicates that the contract has been initialized.
   */
  uint256 private lastInitializedRevision = 0;

  /**
   * @dev Indicates that the contract is in the process of being initialized.
   */
  bool private initializing;

  /**
   * @dev Modifier to use in the initializer function of a contract.
   */
  modifier initializer() {
    uint256 revision = getRevision();
    require(
      initializing || isConstructor() || revision > lastInitializedRevision,
      'Contract instance has already been initialized'
    );

    bool isTopLevelCall = !initializing;
    if (isTopLevelCall) {
      initializing = true;
      lastInitializedRevision = revision;
    }

    _;

    if (isTopLevelCall) {
      initializing = false;
    }
  }

  /// @dev returns the revision number of the contract.
  /// Needs to be defined in the inherited class as a constant.
  function getRevision() internal pure returns (uint256);

  /// @dev Returns true if and only if the function is running in the constructor
  function isConstructor() private view returns (bool) {
    // extcodesize checks the size of the code stored in an address, and
    // address returns the current address. Since the code is still not
    // deployed when running a constructor, any checks on its code size will
    // yield zero, making it an effective way to detect if a contract is
    // under construction or not.
    uint256 cs;
    //solium-disable-next-line
    assembly {
      cs := extcodesize(address)
    }
    return cs == 0;
  }

  // Reserved storage space to allow for layout changes in the future.
  uint256[50] private ______gap;
}

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be aplied to your functions to restrict their use to
 * the owner.
 */
contract Ownable {
  address private _owner;

  event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

  /**
   * @dev Initializes the contract setting the deployer as the initial owner.
   */
  constructor() internal {
    _owner = msg.sender;
    emit OwnershipTransferred(address(0), _owner);
  }

  /**
   * @dev Returns the address of the current owner.
   */
  function owner() public view returns (address) {
    return _owner;
  }

  /**
   * @dev Throws if called by any account other than the owner.
   */
  modifier onlyOwner() {
    require(isOwner(), 'Ownable: caller is not the owner');
    _;
  }

  /**
   * @dev Returns true if the caller is the current owner.
   */
  function isOwner() public view returns (bool) {
    return msg.sender == _owner;
  }

  /**
   * @dev Leaves the contract without owner. It will not be possible to call
   * `onlyOwner` functions anymore. Can only be called by the current owner.
   *
   * > Note: Renouncing ownership will leave the contract without an owner,
   * thereby removing any functionality that is only available to the owner.
   */
  function renounceOwnership() public onlyOwner {
    emit OwnershipTransferred(_owner, address(0));
    _owner = address(0);
  }

  /**
   * @dev Transfers ownership of the contract to a new account (`newOwner`).
   * Can only be called by the current owner.
   */
  function transferOwnership(address newOwner) public onlyOwner {
    _transferOwnership(newOwner);
  }

  /**
   * @dev Transfers ownership of the contract to a new account (`newOwner`).
   */
  function _transferOwnership(address newOwner) internal {
    require(newOwner != address(0), 'Ownable: new owner is the zero address');
    emit OwnershipTransferred(_owner, newOwner);
    _owner = newOwner;
  }
}

/**
 * @title Proxy
 * @dev Implements delegation of calls to other contracts, with proper
 * forwarding of return values and bubbling of failures.
 * It defines a fallback function that delegates all calls to the address
 * returned by the abstract _implementation() internal function.
 */
contract Proxy {
  /**
   * @dev Fallback function.
   * Implemented entirely in `_fallback`.
   */
  function() external payable {
    _fallback();
  }

  /**
   * @return The Address of the implementation.
   */
  function _implementation() internal view returns (address);

  /**
   * @dev Delegates execution to an implementation contract.
   * This is a low level function that doesn't return to its internal call site.
   * It will return to the external caller whatever the implementation returns.
   * @param implementation Address to delegate.
   */
  function _delegate(address implementation) internal {
    //solium-disable-next-line
    assembly {
      // Copy msg.data. We take full control of memory in this inline assembly
      // block because it will not return to Solidity code. We overwrite the
      // Solidity scratch pad at memory position 0.
      calldatacopy(0, 0, calldatasize)

      // Call the implementation.
      // out and outsize are 0 because we don't know the size yet.
      let result := delegatecall(gas, implementation, 0, calldatasize, 0, 0)

      // Copy the returned data.
      returndatacopy(0, 0, returndatasize)

      switch result
      // delegatecall returns 0 on error.
      case 0 {
        revert(0, returndatasize)
      }
      default {
        return(0, returndatasize)
      }
    }
  }

  /**
   * @dev Function that is run as the first thing in the fallback function.
   * Can be redefined in derived contracts to add functionality.
   * Redefinitions must call super._willFallback().
   */
  function _willFallback() internal {}

  /**
   * @dev fallback implementation.
   * Extracted to enable manual triggering.
   */
  function _fallback() internal {
    _willFallback();
    _delegate(_implementation());
  }
}

/**
 * @title BaseUpgradeabilityProxy
 * @dev This contract implements a proxy that allows to change the
 * implementation address to which it will delegate.
 * Such a change is called an implementation upgrade.
 */
contract BaseUpgradeabilityProxy is Proxy {
  /**
   * @dev Emitted when the implementation is upgraded.
   * @param implementation Address of the new implementation.
   */
  event Upgraded(address indexed implementation);

  /**
   * @dev Storage slot with the address of the current implementation.
   * This is the keccak-256 hash of "eip1967.proxy.implementation" subtracted by 1, and is
   * validated in the constructor.
   */
  bytes32 internal constant IMPLEMENTATION_SLOT =
    0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;

  /**
   * @dev Returns the current implementation.
   * @return Address of the current implementation
   */
  function _implementation() internal view returns (address impl) {
    bytes32 slot = IMPLEMENTATION_SLOT;
    //solium-disable-next-line
    assembly {
      impl := sload(slot)
    }
  }

  /**
   * @dev Upgrades the proxy to a new implementation.
   * @param newImplementation Address of the new implementation.
   */
  function _upgradeTo(address newImplementation) internal {
    _setImplementation(newImplementation);
    emit Upgraded(newImplementation);
  }

  /**
   * @dev Sets the implementation address of the proxy.
   * @param newImplementation Address of the new implementation.
   */
  function _setImplementation(address newImplementation) internal {
    require(
      Address.isContract(newImplementation),
      'Cannot set a proxy implementation to a non-contract address'
    );

    bytes32 slot = IMPLEMENTATION_SLOT;

    //solium-disable-next-line
    assembly {
      sstore(slot, newImplementation)
    }
  }
}

/**
 * @title BaseAdminUpgradeabilityProxy
 * @dev This contract combines an upgradeability proxy with an authorization
 * mechanism for administrative tasks.
 * All external functions in this contract must be guarded by the
 * `ifAdmin` modifier. See ethereum/solidity#3864 for a Solidity
 * feature proposal that would enable this to be done automatically.
 */
contract BaseAdminUpgradeabilityProxy is BaseUpgradeabilityProxy {
  /**
   * @dev Emitted when the administration has been transferred.
   * @param previousAdmin Address of the previous admin.
   * @param newAdmin Address of the new admin.
   */
  event AdminChanged(address previousAdmin, address newAdmin);

  /**
   * @dev Storage slot with the admin of the contract.
   * This is the keccak-256 hash of "eip1967.proxy.admin" subtracted by 1, and is
   * validated in the constructor.
   */

  bytes32 internal constant ADMIN_SLOT =
    0xb53127684a568b3173ae13b9f8a6016e243e63b6e8ee1178d6a717850b5d6103;

  /**
   * @dev Modifier to check whether the `msg.sender` is the admin.
   * If it is, it will run the function. Otherwise, it will delegate the call
   * to the implementation.
   */
  modifier ifAdmin() {
    if (msg.sender == _admin()) {
      _;
    } else {
      _fallback();
    }
  }

  /**
   * @return The address of the proxy admin.
   */
  function admin() external ifAdmin returns (address) {
    return _admin();
  }

  /**
   * @return The address of the implementation.
   */
  function implementation() external ifAdmin returns (address) {
    return _implementation();
  }

  /**
   * @dev Changes the admin of the proxy.
   * Only the current admin can call this function.
   * @param newAdmin Address to transfer proxy administration to.
   */
  function changeAdmin(address newAdmin) external ifAdmin {
    require(newAdmin != address(0), 'Cannot change the admin of a proxy to the zero address');
    emit AdminChanged(_admin(), newAdmin);
    _setAdmin(newAdmin);
  }

  /**
   * @dev Upgrade the backing implementation of the proxy.
   * Only the admin can call this function.
   * @param newImplementation Address of the new implementation.
   */
  function upgradeTo(address newImplementation) external ifAdmin {
    _upgradeTo(newImplementation);
  }

  /**
   * @dev Upgrade the backing implementation of the proxy and call a function
   * on the new implementation.
   * This is useful to initialize the proxied contract.
   * @param newImplementation Address of the new implementation.
   * @param data Data to send as msg.data in the low level call.
   * It should include the signature and the parameters of the function to be called, as described in
   * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
   */
  function upgradeToAndCall(
    address newImplementation,
    bytes calldata data
  ) external payable ifAdmin {
    _upgradeTo(newImplementation);
    (bool success, ) = newImplementation.delegatecall(data);
    require(success);
  }

  /**
   * @return The admin slot.
   */
  function _admin() internal view returns (address adm) {
    bytes32 slot = ADMIN_SLOT;
    //solium-disable-next-line
    assembly {
      adm := sload(slot)
    }
  }

  /**
   * @dev Sets the address of the proxy admin.
   * @param newAdmin Address of the new proxy admin.
   */
  function _setAdmin(address newAdmin) internal {
    bytes32 slot = ADMIN_SLOT;
    //solium-disable-next-line
    assembly {
      sstore(slot, newAdmin)
    }
  }

  /**
   * @dev Only fall back when the sender is not the admin.
   */
  function _willFallback() internal {
    require(msg.sender != _admin(), 'Cannot call fallback function from the proxy admin');
    super._willFallback();
  }
}

/**
 * @title UpgradeabilityProxy
 * @dev Extends BaseUpgradeabilityProxy with a constructor for initializing
 * implementation and init data.
 */
contract UpgradeabilityProxy is BaseUpgradeabilityProxy {
  /**
   * @dev Contract constructor.
   * @param _logic Address of the initial implementation.
   * @param _data Data to send as msg.data to the implementation to initialize the proxied contract.
   * It should include the signature and the parameters of the function to be called, as described in
   * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
   * This parameter is optional, if no data is given the initialization call to proxied contract will be skipped.
   */
  constructor(address _logic, bytes memory _data) public payable {
    assert(IMPLEMENTATION_SLOT == bytes32(uint256(keccak256('eip1967.proxy.implementation')) - 1));
    _setImplementation(_logic);
    if (_data.length > 0) {
      (bool success, ) = _logic.delegatecall(_data);
      require(success);
    }
  }
}

/**
 * @title AdminUpgradeabilityProxy
 * @dev Extends from BaseAdminUpgradeabilityProxy with a constructor for
 * initializing the implementation, admin, and init data.
 */
contract AdminUpgradeabilityProxy is BaseAdminUpgradeabilityProxy, UpgradeabilityProxy {
  /**
   * Contract constructor.
   * @param _logic address of the initial implementation.
   * @param _admin Address of the proxy administrator.
   * @param _data Data to send as msg.data to the implementation to initialize the proxied contract.
   * It should include the signature and the parameters of the function to be called, as described in
   * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
   * This parameter is optional, if no data is given the initialization call to proxied contract will be skipped.
   */
  constructor(
    address _logic,
    address _admin,
    bytes memory _data
  ) public payable UpgradeabilityProxy(_logic, _data) {
    assert(ADMIN_SLOT == bytes32(uint256(keccak256('eip1967.proxy.admin')) - 1));
    _setAdmin(_admin);
  }
}

/**
 * @title InitializableUpgradeabilityProxy
 * @dev Extends BaseUpgradeabilityProxy with an initializer for initializing
 * implementation and init data.
 */
contract InitializableUpgradeabilityProxy is BaseUpgradeabilityProxy {
  /**
   * @dev Contract initializer.
   * @param _logic Address of the initial implementation.
   * @param _data Data to send as msg.data to the implementation to initialize the proxied contract.
   * It should include the signature and the parameters of the function to be called, as described in
   * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
   * This parameter is optional, if no data is given the initialization call to proxied contract will be skipped.
   */
  function initialize(address _logic, bytes memory _data) public payable {
    require(_implementation() == address(0));
    assert(IMPLEMENTATION_SLOT == bytes32(uint256(keccak256('eip1967.proxy.implementation')) - 1));
    _setImplementation(_logic);
    if (_data.length > 0) {
      (bool success, ) = _logic.delegatecall(_data);
      require(success);
    }
  }
}

contract AddressStorage {
  mapping(bytes32 => address) private addresses;

  function getAddress(bytes32 _key) public view returns (address) {
    return addresses[_key];
  }

  function _setAddress(bytes32 _key, address _value) internal {
    addresses[_key] = _value;
  }
}

/**
 * @title InitializableAdminUpgradeabilityProxy
 * @dev Extends from BaseAdminUpgradeabilityProxy with an initializer for
 * initializing the implementation, admin, and init data.
 */
contract InitializableAdminUpgradeabilityProxy is
  BaseAdminUpgradeabilityProxy,
  InitializableUpgradeabilityProxy
{
  /**
   * Contract initializer.
   * @param _logic address of the initial implementation.
   * @param _admin Address of the proxy administrator.
   * @param _data Data to send as msg.data to the implementation to initialize the proxied contract.
   * It should include the signature and the parameters of the function to be called, as described in
   * https://solidity.readthedocs.io/en/v0.4.24/abi-spec.html#function-selector-and-argument-encoding.
   * This parameter is optional, if no data is given the initialization call to proxied contract will be skipped.
   */
  function initialize(address _logic, address _admin, bytes memory _data) public payable {
    require(_implementation() == address(0));
    InitializableUpgradeabilityProxy.initialize(_logic, _data);
    assert(ADMIN_SLOT == bytes32(uint256(keccak256('eip1967.proxy.admin')) - 1));
    _setAdmin(_admin);
  }
}

/**
@title ILendingPoolAddressesProvider interface
@notice provides the interface to fetch the LendingPoolCore address
 */

contract ILendingPoolAddressesProvider {
  function getLendingPool() public view returns (address);

  function setLendingPoolImpl(address _pool) public;

  function getLendingPoolCore() public view returns (address payable);

  function setLendingPoolCoreImpl(address _lendingPoolCore) public;

  function getLendingPoolConfigurator() public view returns (address);

  function setLendingPoolConfiguratorImpl(address _configurator) public;

  function getLendingPoolDataProvider() public view returns (address);

  function setLendingPoolDataProviderImpl(address _provider) public;

  function getLendingPoolParametersProvider() public view returns (address);

  function setLendingPoolParametersProviderImpl(address _parametersProvider) public;

  function getTokenDistributor() public view returns (address);

  function setTokenDistributor(address _tokenDistributor) public;

  function getFeeProvider() public view returns (address);

  function setFeeProviderImpl(address _feeProvider) public;

  function getLendingPoolLiquidationManager() public view returns (address);

  function setLendingPoolLiquidationManager(address _manager) public;

  function getLendingPoolManager() public view returns (address);

  function setLendingPoolManager(address _lendingPoolManager) public;

  function getPriceOracle() public view returns (address);

  function setPriceOracle(address _priceOracle) public;

  function getLendingRateOracle() public view returns (address);

  function setLendingRateOracle(address _lendingRateOracle) public;
}

/**
 * @title LendingPoolAddressesProvider contract
 * @notice Is the main registry of the protocol. All the different components of the protocol are accessible
 * through the addresses provider.
 * @author Aave
 **/

contract LendingPoolAddressesProvider is Ownable, ILendingPoolAddressesProvider, AddressStorage {
  //events
  event LendingPoolUpdated(address indexed newAddress);
  event LendingPoolCoreUpdated(address indexed newAddress);
  event LendingPoolParametersProviderUpdated(address indexed newAddress);
  event LendingPoolManagerUpdated(address indexed newAddress);
  event LendingPoolConfiguratorUpdated(address indexed newAddress);
  event LendingPoolLiquidationManagerUpdated(address indexed newAddress);
  event LendingPoolDataProviderUpdated(address indexed newAddress);
  event EthereumAddressUpdated(address indexed newAddress);
  event PriceOracleUpdated(address indexed newAddress);
  event LendingRateOracleUpdated(address indexed newAddress);
  event FeeProviderUpdated(address indexed newAddress);
  event TokenDistributorUpdated(address indexed newAddress);

  event ProxyCreated(bytes32 id, address indexed newAddress);

  bytes32 private constant LENDING_POOL = 'LENDING_POOL';
  bytes32 private constant LENDING_POOL_CORE = 'LENDING_POOL_CORE';
  bytes32 private constant LENDING_POOL_CONFIGURATOR = 'LENDING_POOL_CONFIGURATOR';
  bytes32 private constant LENDING_POOL_PARAMETERS_PROVIDER = 'PARAMETERS_PROVIDER';
  bytes32 private constant LENDING_POOL_MANAGER = 'LENDING_POOL_MANAGER';
  bytes32 private constant LENDING_POOL_LIQUIDATION_MANAGER = 'LIQUIDATION_MANAGER';
  bytes32 private constant LENDING_POOL_FLASHLOAN_PROVIDER = 'FLASHLOAN_PROVIDER';
  bytes32 private constant DATA_PROVIDER = 'DATA_PROVIDER';
  bytes32 private constant ETHEREUM_ADDRESS = 'ETHEREUM_ADDRESS';
  bytes32 private constant PRICE_ORACLE = 'PRICE_ORACLE';
  bytes32 private constant LENDING_RATE_ORACLE = 'LENDING_RATE_ORACLE';
  bytes32 private constant FEE_PROVIDER = 'FEE_PROVIDER';
  bytes32 private constant WALLET_BALANCE_PROVIDER = 'WALLET_BALANCE_PROVIDER';
  bytes32 private constant TOKEN_DISTRIBUTOR = 'TOKEN_DISTRIBUTOR';

  /**
   * @dev returns the address of the LendingPool proxy
   * @return the lending pool proxy address
   **/
  function getLendingPool() public view returns (address) {
    return getAddress(LENDING_POOL);
  }

  /**
   * @dev updates the implementation of the lending pool
   * @param _pool the new lending pool implementation
   **/
  function setLendingPoolImpl(address _pool) public onlyOwner {
    updateImplInternal(LENDING_POOL, _pool);
    emit LendingPoolUpdated(_pool);
  }

  /**
   * @dev returns the address of the LendingPoolCore proxy
   * @return the lending pool core proxy address
   */
  function getLendingPoolCore() public view returns (address payable) {
    address payable core = address(uint160(getAddress(LENDING_POOL_CORE)));
    return core;
  }

  /**
   * @dev updates the implementation of the lending pool core
   * @param _lendingPoolCore the new lending pool core implementation
   **/
  function setLendingPoolCoreImpl(address _lendingPoolCore) public onlyOwner {
    updateImplInternal(LENDING_POOL_CORE, _lendingPoolCore);
    emit LendingPoolCoreUpdated(_lendingPoolCore);
  }

  /**
   * @dev returns the address of the LendingPoolConfigurator proxy
   * @return the lending pool configurator proxy address
   **/
  function getLendingPoolConfigurator() public view returns (address) {
    return getAddress(LENDING_POOL_CONFIGURATOR);
  }

  /**
   * @dev updates the implementation of the lending pool configurator
   * @param _configurator the new lending pool configurator implementation
   **/
  function setLendingPoolConfiguratorImpl(address _configurator) public onlyOwner {
    updateImplInternal(LENDING_POOL_CONFIGURATOR, _configurator);
    emit LendingPoolConfiguratorUpdated(_configurator);
  }

  /**
   * @dev returns the address of the LendingPoolDataProvider proxy
   * @return the lending pool data provider proxy address
   */
  function getLendingPoolDataProvider() public view returns (address) {
    return getAddress(DATA_PROVIDER);
  }

  /**
   * @dev updates the implementation of the lending pool data provider
   * @param _provider the new lending pool data provider implementation
   **/
  function setLendingPoolDataProviderImpl(address _provider) public onlyOwner {
    updateImplInternal(DATA_PROVIDER, _provider);
    emit LendingPoolDataProviderUpdated(_provider);
  }

  /**
   * @dev returns the address of the LendingPoolParametersProvider proxy
   * @return the address of the Lending pool parameters provider proxy
   **/
  function getLendingPoolParametersProvider() public view returns (address) {
    return getAddress(LENDING_POOL_PARAMETERS_PROVIDER);
  }

  /**
   * @dev updates the implementation of the lending pool parameters provider
   * @param _parametersProvider the new lending pool parameters provider implementation
   **/
  function setLendingPoolParametersProviderImpl(address _parametersProvider) public onlyOwner {
    updateImplInternal(LENDING_POOL_PARAMETERS_PROVIDER, _parametersProvider);
    emit LendingPoolParametersProviderUpdated(_parametersProvider);
  }

  /**
   * @dev returns the address of the FeeProvider proxy
   * @return the address of the Fee provider proxy
   **/
  function getFeeProvider() public view returns (address) {
    return getAddress(FEE_PROVIDER);
  }

  /**
   * @dev updates the implementation of the FeeProvider proxy
   * @param _feeProvider the new lending pool fee provider implementation
   **/
  function setFeeProviderImpl(address _feeProvider) public onlyOwner {
    updateImplInternal(FEE_PROVIDER, _feeProvider);
    emit FeeProviderUpdated(_feeProvider);
  }

  /**
   * @dev returns the address of the LendingPoolLiquidationManager. Since the manager is used
   * through delegateCall within the LendingPool contract, the proxy contract pattern does not work properly hence
   * the addresses are changed directly.
   * @return the address of the Lending pool liquidation manager
   **/

  function getLendingPoolLiquidationManager() public view returns (address) {
    return getAddress(LENDING_POOL_LIQUIDATION_MANAGER);
  }

  /**
   * @dev updates the address of the Lending pool liquidation manager
   * @param _manager the new lending pool liquidation manager address
   **/
  function setLendingPoolLiquidationManager(address _manager) public onlyOwner {
    _setAddress(LENDING_POOL_LIQUIDATION_MANAGER, _manager);
    emit LendingPoolLiquidationManagerUpdated(_manager);
  }

  /**
   * @dev the functions below are storing specific addresses that are outside the context of the protocol
   * hence the upgradable proxy pattern is not used
   **/

  function getLendingPoolManager() public view returns (address) {
    return getAddress(LENDING_POOL_MANAGER);
  }

  function setLendingPoolManager(address _lendingPoolManager) public onlyOwner {
    _setAddress(LENDING_POOL_MANAGER, _lendingPoolManager);
    emit LendingPoolManagerUpdated(_lendingPoolManager);
  }

  function getPriceOracle() public view returns (address) {
    return getAddress(PRICE_ORACLE);
  }

  function setPriceOracle(address _priceOracle) public onlyOwner {
    _setAddress(PRICE_ORACLE, _priceOracle);
    emit PriceOracleUpdated(_priceOracle);
  }

  function getLendingRateOracle() public view returns (address) {
    return getAddress(LENDING_RATE_ORACLE);
  }

  function setLendingRateOracle(address _lendingRateOracle) public onlyOwner {
    _setAddress(LENDING_RATE_ORACLE, _lendingRateOracle);
    emit LendingRateOracleUpdated(_lendingRateOracle);
  }

  function getTokenDistributor() public view returns (address) {
    return getAddress(TOKEN_DISTRIBUTOR);
  }

  function setTokenDistributor(address _tokenDistributor) public onlyOwner {
    _setAddress(TOKEN_DISTRIBUTOR, _tokenDistributor);
    emit TokenDistributorUpdated(_tokenDistributor);
  }

  /**
   * @dev internal function to update the implementation of a specific component of the protocol
   * @param _id the id of the contract to be updated
   * @param _newAddress the address of the new implementation
   **/
  function updateImplInternal(bytes32 _id, address _newAddress) internal {
    address payable proxyAddress = address(uint160(getAddress(_id)));

    InitializableAdminUpgradeabilityProxy proxy = InitializableAdminUpgradeabilityProxy(
      proxyAddress
    );
    bytes memory params = abi.encodeWithSignature('initialize(address)', address(this));

    if (proxyAddress == address(0)) {
      proxy = new InitializableAdminUpgradeabilityProxy();
      proxy.initialize(_newAddress, address(this), params);
      _setAddress(_id, address(proxy));
      emit ProxyCreated(_id, address(proxy));
    } else {
      proxy.upgradeToAndCall(_newAddress, params);
    }
  }
}

contract UintStorage {
  mapping(bytes32 => uint256) private uints;

  function getUint(bytes32 _key) public view returns (uint256) {
    return uints[_key];
  }

  function _setUint(bytes32 _key, uint256 _value) internal {
    uints[_key] = _value;
  }
}

/**
 * @title LendingPoolParametersProvider
 * @author Aave
 * @notice stores the configuration parameters of the Lending Pool contract
 **/

contract LendingPoolParametersProvider is VersionedInitializable {
  uint256 private constant MAX_STABLE_RATE_BORROW_SIZE_PERCENT = 25;
  uint256 private constant REBALANCE_DOWN_RATE_DELTA = (1e27) / 5;
  uint256 private constant FLASHLOAN_FEE_TOTAL = 35;
  uint256 private constant FLASHLOAN_FEE_PROTOCOL = 3000;

  uint256 private constant DATA_PROVIDER_REVISION = 0x1;

  function getRevision() internal pure returns (uint256) {
    return DATA_PROVIDER_REVISION;
  }

  /**
   * @dev initializes the LendingPoolParametersProvider after it's added to the proxy
   * @param _addressesProvider the address of the LendingPoolAddressesProvider
   */
  function initialize(address _addressesProvider) public initializer {}

  /**
   * @dev returns the maximum stable rate borrow size, in percentage of the available liquidity.
   **/
  function getMaxStableRateBorrowSizePercent() external pure returns (uint256) {
    return MAX_STABLE_RATE_BORROW_SIZE_PERCENT;
  }

  /**
   * @dev returns the delta between the current stable rate and the user stable rate at
   *      which the borrow position of the user will be rebalanced (scaled down)
   **/
  function getRebalanceDownRateDelta() external pure returns (uint256) {
    return REBALANCE_DOWN_RATE_DELTA;
  }

  /**
   * @dev returns the fee applied to a flashloan and the portion to redirect to the protocol, in basis points.
   **/
  function getFlashLoanFeesInBips() external pure returns (uint256, uint256) {
    return (FLASHLOAN_FEE_TOTAL, FLASHLOAN_FEE_PROTOCOL);
  }
}

/**
 * @title CoreLibrary library
 * @author Aave
 * @notice Defines the data structures of the reserves and the user data
 **/
library CoreLibrary {
  using SafeMath for uint256;
  using WadRayMath for uint256;

  enum InterestRateMode {
    NONE,
    STABLE,
    VARIABLE
  }

  uint256 internal constant SECONDS_PER_YEAR = 365 days;

  struct UserReserveData {
    //principal amount borrowed by the user.
    uint256 principalBorrowBalance;
    //cumulated variable borrow index for the user. Expressed in ray
    uint256 lastVariableBorrowCumulativeIndex;
    //origination fee cumulated by the user
    uint256 originationFee;
    // stable borrow rate at which the user has borrowed. Expressed in ray
    uint256 stableBorrowRate;
    uint40 lastUpdateTimestamp;
    //defines if a specific deposit should or not be used as a collateral in borrows
    bool useAsCollateral;
  }

  struct ReserveData {
    /**
     * @dev refer to the whitepaper, section 1.1 basic concepts for a formal description of these properties.
     **/
    //the liquidity index. Expressed in ray
    uint256 lastLiquidityCumulativeIndex;
    //the current supply rate. Expressed in ray
    uint256 currentLiquidityRate;
    //the total borrows of the reserve at a stable rate. Expressed in the currency decimals
    uint256 totalBorrowsStable;
    //the total borrows of the reserve at a variable rate. Expressed in the currency decimals
    uint256 totalBorrowsVariable;
    //the current variable borrow rate. Expressed in ray
    uint256 currentVariableBorrowRate;
    //the current stable borrow rate. Expressed in ray
    uint256 currentStableBorrowRate;
    //the current average stable borrow rate (weighted average of all the different stable rate loans). Expressed in ray
    uint256 currentAverageStableBorrowRate;
    //variable borrow index. Expressed in ray
    uint256 lastVariableBorrowCumulativeIndex;
    //the ltv of the reserve. Expressed in percentage (0-100)
    uint256 baseLTVasCollateral;
    //the liquidation threshold of the reserve. Expressed in percentage (0-100)
    uint256 liquidationThreshold;
    //the liquidation bonus of the reserve. Expressed in percentage
    uint256 liquidationBonus;
    //the decimals of the reserve asset
    uint256 decimals;
    /**
     * @dev address of the aToken representing the asset
     **/
    address aTokenAddress;
    /**
     * @dev address of the interest rate strategy contract
     **/
    address interestRateStrategyAddress;
    uint40 lastUpdateTimestamp;
    // borrowingEnabled = true means users can borrow from this reserve
    bool borrowingEnabled;
    // usageAsCollateralEnabled = true means users can use this reserve as collateral
    bool usageAsCollateralEnabled;
    // isStableBorrowRateEnabled = true means users can borrow at a stable rate
    bool isStableBorrowRateEnabled;
    // isActive = true means the reserve has been activated and properly configured
    bool isActive;
    // isFreezed = true means the reserve only allows repays and redeems, but not deposits, new borrowings or rate swap
    bool isFreezed;
  }

  /**
   * @dev returns the ongoing normalized income for the reserve.
   * a value of 1e27 means there is no income. As time passes, the income is accrued.
   * A value of 2*1e27 means that the income of the reserve is double the initial amount.
   * @param _reserve the reserve object
   * @return the normalized income. expressed in ray
   **/
  function getNormalizedIncome(
    CoreLibrary.ReserveData storage _reserve
  ) internal view returns (uint256) {
    uint256 cumulated = calculateLinearInterest(
      _reserve.currentLiquidityRate,
      _reserve.lastUpdateTimestamp
    ).rayMul(_reserve.lastLiquidityCumulativeIndex);

    return cumulated;
  }

  /**
   * @dev Updates the liquidity cumulative index Ci and variable borrow cumulative index Bvc. Refer to the whitepaper for
   * a formal specification.
   * @param _self the reserve object
   **/
  function updateCumulativeIndexes(ReserveData storage _self) internal {
    uint256 totalBorrows = getTotalBorrows(_self);

    if (totalBorrows > 0) {
      //only cumulating if there is any income being produced
      uint256 cumulatedLiquidityInterest = calculateLinearInterest(
        _self.currentLiquidityRate,
        _self.lastUpdateTimestamp
      );

      _self.lastLiquidityCumulativeIndex = cumulatedLiquidityInterest.rayMul(
        _self.lastLiquidityCumulativeIndex
      );

      uint256 cumulatedVariableBorrowInterest = calculateCompoundedInterest(
        _self.currentVariableBorrowRate,
        _self.lastUpdateTimestamp
      );
      _self.lastVariableBorrowCumulativeIndex = cumulatedVariableBorrowInterest.rayMul(
        _self.lastVariableBorrowCumulativeIndex
      );
    }
  }

  /**
   * @dev accumulates a predefined amount of asset to the reserve as a fixed, one time income. Used for example to accumulate
   * the flashloan fee to the reserve, and spread it through the depositors.
   * @param _self the reserve object
   * @param _totalLiquidity the total liquidity available in the reserve
   * @param _amount the amount to accomulate
   **/
  function cumulateToLiquidityIndex(
    ReserveData storage _self,
    uint256 _totalLiquidity,
    uint256 _amount
  ) internal {
    uint256 amountToLiquidityRatio = _amount.wadToRay().rayDiv(_totalLiquidity.wadToRay());

    uint256 cumulatedLiquidity = amountToLiquidityRatio.add(WadRayMath.ray());

    _self.lastLiquidityCumulativeIndex = cumulatedLiquidity.rayMul(
      _self.lastLiquidityCumulativeIndex
    );
  }

  /**
   * @dev initializes a reserve
   * @param _self the reserve object
   * @param _aTokenAddress the address of the overlying atoken contract
   * @param _decimals the number of decimals of the underlying asset
   * @param _interestRateStrategyAddress the address of the interest rate strategy contract
   **/
  function init(
    ReserveData storage _self,
    address _aTokenAddress,
    uint256 _decimals,
    address _interestRateStrategyAddress
  ) external {
    require(_self.aTokenAddress == address(0), 'Reserve has already been initialized');

    if (_self.lastLiquidityCumulativeIndex == 0) {
      //if the reserve has not been initialized yet
      _self.lastLiquidityCumulativeIndex = WadRayMath.ray();
    }

    if (_self.lastVariableBorrowCumulativeIndex == 0) {
      _self.lastVariableBorrowCumulativeIndex = WadRayMath.ray();
    }

    _self.aTokenAddress = _aTokenAddress;
    _self.decimals = _decimals;

    _self.interestRateStrategyAddress = _interestRateStrategyAddress;
    _self.isActive = true;
    _self.isFreezed = false;
  }

  /**
   * @dev enables borrowing on a reserve
   * @param _self the reserve object
   * @param _stableBorrowRateEnabled true if the stable borrow rate must be enabled by default, false otherwise
   **/
  function enableBorrowing(ReserveData storage _self, bool _stableBorrowRateEnabled) external {
    require(_self.borrowingEnabled == false, 'Reserve is already enabled');

    _self.borrowingEnabled = true;
    _self.isStableBorrowRateEnabled = _stableBorrowRateEnabled;
  }

  /**
   * @dev disables borrowing on a reserve
   * @param _self the reserve object
   **/
  function disableBorrowing(ReserveData storage _self) external {
    _self.borrowingEnabled = false;
  }

  /**
   * @dev enables a reserve to be used as collateral
   * @param _self the reserve object
   * @param _baseLTVasCollateral the loan to value of the asset when used as collateral
   * @param _liquidationThreshold the threshold at which loans using this asset as collateral will be considered undercollateralized
   * @param _liquidationBonus the bonus liquidators receive to liquidate this asset
   **/
  function enableAsCollateral(
    ReserveData storage _self,
    uint256 _baseLTVasCollateral,
    uint256 _liquidationThreshold,
    uint256 _liquidationBonus
  ) external {
    require(_self.usageAsCollateralEnabled == false, 'Reserve is already enabled as collateral');

    _self.usageAsCollateralEnabled = true;
    _self.baseLTVasCollateral = _baseLTVasCollateral;
    _self.liquidationThreshold = _liquidationThreshold;
    _self.liquidationBonus = _liquidationBonus;

    if (_self.lastLiquidityCumulativeIndex == 0)
      _self.lastLiquidityCumulativeIndex = WadRayMath.ray();
  }

  /**
   * @dev disables a reserve as collateral
   * @param _self the reserve object
   **/
  function disableAsCollateral(ReserveData storage _self) external {
    _self.usageAsCollateralEnabled = false;
  }

  /**
   * @dev calculates the compounded borrow balance of a user
   * @param _self the userReserve object
   * @param _reserve the reserve object
   * @return the user compounded borrow balance
   **/
  function getCompoundedBorrowBalance(
    CoreLibrary.UserReserveData storage _self,
    CoreLibrary.ReserveData storage _reserve
  ) internal view returns (uint256) {
    if (_self.principalBorrowBalance == 0) return 0;

    uint256 principalBorrowBalanceRay = _self.principalBorrowBalance.wadToRay();
    uint256 compoundedBalance = 0;
    uint256 cumulatedInterest = 0;

    if (_self.stableBorrowRate > 0) {
      cumulatedInterest = calculateCompoundedInterest(
        _self.stableBorrowRate,
        _self.lastUpdateTimestamp
      );
    } else {
      //variable interest
      cumulatedInterest = calculateCompoundedInterest(
        _reserve.currentVariableBorrowRate,
        _reserve.lastUpdateTimestamp
      ).rayMul(_reserve.lastVariableBorrowCumulativeIndex).rayDiv(
          _self.lastVariableBorrowCumulativeIndex
        );
    }

    compoundedBalance = principalBorrowBalanceRay.rayMul(cumulatedInterest).rayToWad();

    if (compoundedBalance == _self.principalBorrowBalance) {
      //solium-disable-next-line
      if (_self.lastUpdateTimestamp != block.timestamp) {
        //no interest cumulation because of the rounding - we add 1 wei
        //as symbolic cumulated interest to avoid interest free loans.

        return _self.principalBorrowBalance.add(1 wei);
      }
    }

    return compoundedBalance;
  }

  /**
   * @dev increases the total borrows at a stable rate on a specific reserve and updates the
   * average stable rate consequently
   * @param _reserve the reserve object
   * @param _amount the amount to add to the total borrows stable
   * @param _rate the rate at which the amount has been borrowed
   **/
  function increaseTotalBorrowsStableAndUpdateAverageRate(
    ReserveData storage _reserve,
    uint256 _amount,
    uint256 _rate
  ) internal {
    if (_amount == 0) {
      return;
    }

    uint256 previousTotalBorrowStable = _reserve.totalBorrowsStable;
    //updating reserve borrows stable
    _reserve.totalBorrowsStable = _reserve.totalBorrowsStable.add(_amount);

    //update the average stable rate
    //weighted average of all the borrows
    uint256 weightedLastBorrow = _amount.wadToRay().rayMul(_rate);
    uint256 weightedPreviousTotalBorrows = previousTotalBorrowStable.wadToRay().rayMul(
      _reserve.currentAverageStableBorrowRate
    );

    _reserve.currentAverageStableBorrowRate = weightedLastBorrow
      .add(weightedPreviousTotalBorrows)
      .rayDiv(_reserve.totalBorrowsStable.wadToRay());
  }

  /**
   * @dev decreases the total borrows at a stable rate on a specific reserve and updates the
   * average stable rate consequently
   * @param _reserve the reserve object
   * @param _amount the amount to substract to the total borrows stable
   * @param _rate the rate at which the amount has been repaid
   **/
  function decreaseTotalBorrowsStableAndUpdateAverageRate(
    ReserveData storage _reserve,
    uint256 _amount,
    uint256 _rate
  ) internal {
    uint256 previousTotalBorrowStable = _reserve.totalBorrowsStable;

    if (previousTotalBorrowStable == 0 || _amount >= previousTotalBorrowStable) {
      _reserve.totalBorrowsStable = 0;
      _reserve.currentAverageStableBorrowRate = 0; // no income if there are no stable rate borrows
      return;
    }

    //updating reserve borrows stable
    _reserve.totalBorrowsStable = _reserve.totalBorrowsStable.sub(_amount);

    //update the average stable rate
    //weighted average of all the borrows
    uint256 weightedLastBorrow = _amount.wadToRay().rayMul(_rate);
    uint256 weightedPreviousTotalBorrows = previousTotalBorrowStable.wadToRay().rayMul(
      _reserve.currentAverageStableBorrowRate
    );

    if (weightedPreviousTotalBorrows <= weightedLastBorrow) {
      _reserve.totalBorrowsStable = 0;
      _reserve.currentAverageStableBorrowRate = 0; // no income if there are no stable rate borrows
      return;
    }

    _reserve.currentAverageStableBorrowRate = weightedPreviousTotalBorrows
      .sub(weightedLastBorrow)
      .rayDiv(_reserve.totalBorrowsStable.wadToRay());
  }

  /**
   * @dev increases the total borrows at a variable rate
   * @param _reserve the reserve object
   * @param _amount the amount to add to the total borrows variable
   **/
  function increaseTotalBorrowsVariable(ReserveData storage _reserve, uint256 _amount) internal {
    _reserve.totalBorrowsVariable = _reserve.totalBorrowsVariable.add(_amount);
  }

  /**
   * @dev decreases the total borrows at a variable rate
   * @param _reserve the reserve object
   * @param _amount the amount to substract to the total borrows variable
   **/
  function decreaseTotalBorrowsVariable(ReserveData storage _reserve, uint256 _amount) internal {
    require(
      _reserve.totalBorrowsVariable >= _amount,
      'The amount that is being subtracted from the variable total borrows is incorrect'
    );
    _reserve.totalBorrowsVariable = _reserve.totalBorrowsVariable.sub(_amount);
  }

  /**
   * @dev function to calculate the interest using a linear interest rate formula
   * @param _rate the interest rate, in ray
   * @param _lastUpdateTimestamp the timestamp of the last update of the interest
   * @return the interest rate linearly accumulated during the timeDelta, in ray
   **/

  function calculateLinearInterest(
    uint256 _rate,
    uint40 _lastUpdateTimestamp
  ) internal view returns (uint256) {
    //solium-disable-next-line
    uint256 timeDifference = block.timestamp.sub(uint256(_lastUpdateTimestamp));

    uint256 timeDelta = timeDifference.wadToRay().rayDiv(SECONDS_PER_YEAR.wadToRay());

    return _rate.rayMul(timeDelta).add(WadRayMath.ray());
  }

  /**
   * @dev function to calculate the interest using a compounded interest rate formula
   * @param _rate the interest rate, in ray
   * @param _lastUpdateTimestamp the timestamp of the last update of the interest
   * @return the interest rate compounded during the timeDelta, in ray
   **/
  function calculateCompoundedInterest(
    uint256 _rate,
    uint40 _lastUpdateTimestamp
  ) internal view returns (uint256) {
    //solium-disable-next-line
    uint256 timeDifference = block.timestamp.sub(uint256(_lastUpdateTimestamp));

    uint256 ratePerSecond = _rate.div(SECONDS_PER_YEAR);

    return ratePerSecond.add(WadRayMath.ray()).rayPow(timeDifference);
  }

  /**
   * @dev returns the total borrows on the reserve
   * @param _reserve the reserve object
   * @return the total borrows (stable + variable)
   **/
  function getTotalBorrows(
    CoreLibrary.ReserveData storage _reserve
  ) internal view returns (uint256) {
    return _reserve.totalBorrowsStable.add(_reserve.totalBorrowsVariable);
  }
}

/**
 * @title IPriceOracleGetter interface
 * @notice Interface for the Aave price oracle.
 **/

interface IPriceOracleGetter {
  /**
   * @dev returns the asset price in ETH
   * @param _asset the address of the asset
   * @return the ETH price of the asset
   **/
  function getAssetPrice(address _asset) external view returns (uint256);
}

/**
 * @title IFeeProvider interface
 * @notice Interface for the Aave fee provider.
 **/

interface IFeeProvider {
  function calculateLoanOriginationFee(
    address _user,
    uint256 _amount
  ) external view returns (uint256);

  function getLoanOriginationFeePercentage() external view returns (uint256);
}

/**
 * @title LendingPoolDataProvider contract
 * @author Aave
 * @notice Implements functions to fetch data from the core, and aggregate them in order to allow computation
 * on the compounded balances and the account balances in ETH
 **/
contract LendingPoolDataProvider is VersionedInitializable {
  using SafeMath for uint256;
  using WadRayMath for uint256;

  LendingPoolCore public core;
  LendingPoolAddressesProvider public addressesProvider;

  /**
   * @dev specifies the health factor threshold at which the user position is liquidated.
   * 1e18 by default, if the health factor drops below 1e18, the loan can be liquidated.
   **/
  uint256 public constant HEALTH_FACTOR_LIQUIDATION_THRESHOLD = 1e18;

  uint256 public constant DATA_PROVIDER_REVISION = 0x1;

  function getRevision() internal pure returns (uint256) {
    return DATA_PROVIDER_REVISION;
  }

  function initialize(LendingPoolAddressesProvider _addressesProvider) public initializer {
    addressesProvider = _addressesProvider;
    core = LendingPoolCore(_addressesProvider.getLendingPoolCore());
  }

  /**
   * @dev struct to hold calculateUserGlobalData() local computations
   **/
  struct UserGlobalDataLocalVars {
    uint256 reserveUnitPrice;
    uint256 tokenUnit;
    uint256 compoundedLiquidityBalance;
    uint256 compoundedBorrowBalance;
    uint256 reserveDecimals;
    uint256 baseLtv;
    uint256 liquidationThreshold;
    uint256 originationFee;
    bool usageAsCollateralEnabled;
    bool userUsesReserveAsCollateral;
    address currentReserve;
  }

  /**
   * @dev calculates the user data across the reserves.
   * this includes the total liquidity/collateral/borrow balances in ETH,
   * the average Loan To Value, the average Liquidation Ratio, and the Health factor.
   * @param _user the address of the user
   * @return the total liquidity, total collateral, total borrow balances of the user in ETH.
   * also the average Ltv, liquidation threshold, and the health factor
   **/
  function calculateUserGlobalData(
    address _user
  )
    public
    view
    returns (
      uint256 totalLiquidityBalanceETH,
      uint256 totalCollateralBalanceETH,
      uint256 totalBorrowBalanceETH,
      uint256 totalFeesETH,
      uint256 currentLtv,
      uint256 currentLiquidationThreshold,
      uint256 healthFactor,
      bool healthFactorBelowThreshold
    )
  {
    IPriceOracleGetter oracle = IPriceOracleGetter(addressesProvider.getPriceOracle());

    // Usage of a memory struct of vars to avoid "Stack too deep" errors due to local variables
    UserGlobalDataLocalVars memory vars;

    address[] memory reserves = core.getReserves();

    for (uint256 i = 0; i < reserves.length; i++) {
      vars.currentReserve = reserves[i];

      (
        vars.compoundedLiquidityBalance,
        vars.compoundedBorrowBalance,
        vars.originationFee,
        vars.userUsesReserveAsCollateral
      ) = core.getUserBasicReserveData(vars.currentReserve, _user);

      if (vars.compoundedLiquidityBalance == 0 && vars.compoundedBorrowBalance == 0) {
        continue;
      }

      //fetch reserve data
      (
        vars.reserveDecimals,
        vars.baseLtv,
        vars.liquidationThreshold,
        vars.usageAsCollateralEnabled
      ) = core.getReserveConfiguration(vars.currentReserve);

      vars.tokenUnit = 10 ** vars.reserveDecimals;
      vars.reserveUnitPrice = oracle.getAssetPrice(vars.currentReserve);

      //liquidity and collateral balance
      if (vars.compoundedLiquidityBalance > 0) {
        uint256 liquidityBalanceETH = vars
          .reserveUnitPrice
          .mul(vars.compoundedLiquidityBalance)
          .div(vars.tokenUnit);
        totalLiquidityBalanceETH = totalLiquidityBalanceETH.add(liquidityBalanceETH);

        if (vars.usageAsCollateralEnabled && vars.userUsesReserveAsCollateral) {
          totalCollateralBalanceETH = totalCollateralBalanceETH.add(liquidityBalanceETH);
          currentLtv = currentLtv.add(liquidityBalanceETH.mul(vars.baseLtv));
          currentLiquidationThreshold = currentLiquidationThreshold.add(
            liquidityBalanceETH.mul(vars.liquidationThreshold)
          );
        }
      }

      if (vars.compoundedBorrowBalance > 0) {
        totalBorrowBalanceETH = totalBorrowBalanceETH.add(
          vars.reserveUnitPrice.mul(vars.compoundedBorrowBalance).div(vars.tokenUnit)
        );
        totalFeesETH = totalFeesETH.add(
          vars.originationFee.mul(vars.reserveUnitPrice).div(vars.tokenUnit)
        );
      }
    }

    currentLtv = totalCollateralBalanceETH > 0 ? currentLtv.div(totalCollateralBalanceETH) : 0;
    currentLiquidationThreshold = totalCollateralBalanceETH > 0
      ? currentLiquidationThreshold.div(totalCollateralBalanceETH)
      : 0;

    healthFactor = calculateHealthFactorFromBalancesInternal(
      totalCollateralBalanceETH,
      totalBorrowBalanceETH,
      totalFeesETH,
      currentLiquidationThreshold
    );
    healthFactorBelowThreshold = healthFactor < HEALTH_FACTOR_LIQUIDATION_THRESHOLD;
  }

  struct balanceDecreaseAllowedLocalVars {
    uint256 decimals;
    uint256 collateralBalanceETH;
    uint256 borrowBalanceETH;
    uint256 totalFeesETH;
    uint256 currentLiquidationThreshold;
    uint256 reserveLiquidationThreshold;
    uint256 amountToDecreaseETH;
    uint256 collateralBalancefterDecrease;
    uint256 liquidationThresholdAfterDecrease;
    uint256 healthFactorAfterDecrease;
    bool reserveUsageAsCollateralEnabled;
  }

  /**
   * @dev check if a specific balance decrease is allowed (i.e. doesn't bring the user borrow position health factor under 1e18)
   * @param _reserve the address of the reserve
   * @param _user the address of the user
   * @param _amount the amount to decrease
   * @return true if the decrease of the balance is allowed
   **/

  function balanceDecreaseAllowed(
    address _reserve,
    address _user,
    uint256 _amount
  ) external view returns (bool) {
    // Usage of a memory struct of vars to avoid "Stack too deep" errors due to local variables
    balanceDecreaseAllowedLocalVars memory vars;

    (vars.decimals, , vars.reserveLiquidationThreshold, vars.reserveUsageAsCollateralEnabled) = core
      .getReserveConfiguration(_reserve);

    if (
      !vars.reserveUsageAsCollateralEnabled ||
      !core.isUserUseReserveAsCollateralEnabled(_reserve, _user)
    ) {
      return true; //if reserve is not used as collateral, no reasons to block the transfer
    }

    (
      ,
      vars.collateralBalanceETH,
      vars.borrowBalanceETH,
      vars.totalFeesETH,
      ,
      vars.currentLiquidationThreshold,
      ,

    ) = calculateUserGlobalData(_user);

    if (vars.borrowBalanceETH == 0) {
      return true; //no borrows - no reasons to block the transfer
    }

    IPriceOracleGetter oracle = IPriceOracleGetter(addressesProvider.getPriceOracle());

    vars.amountToDecreaseETH = oracle.getAssetPrice(_reserve).mul(_amount).div(10 ** vars.decimals);

    vars.collateralBalancefterDecrease = vars.collateralBalanceETH.sub(vars.amountToDecreaseETH);

    //if there is a borrow, there can't be 0 collateral
    if (vars.collateralBalancefterDecrease == 0) {
      return false;
    }

    vars.liquidationThresholdAfterDecrease = vars
      .collateralBalanceETH
      .mul(vars.currentLiquidationThreshold)
      .sub(vars.amountToDecreaseETH.mul(vars.reserveLiquidationThreshold))
      .div(vars.collateralBalancefterDecrease);

    uint256 healthFactorAfterDecrease = calculateHealthFactorFromBalancesInternal(
      vars.collateralBalancefterDecrease,
      vars.borrowBalanceETH,
      vars.totalFeesETH,
      vars.liquidationThresholdAfterDecrease
    );

    return healthFactorAfterDecrease > HEALTH_FACTOR_LIQUIDATION_THRESHOLD;
  }

  /**
   * @notice calculates the amount of collateral needed in ETH to cover a new borrow.
   * @param _reserve the reserve from which the user wants to borrow
   * @param _amount the amount the user wants to borrow
   * @param _fee the fee for the amount that the user needs to cover
   * @param _userCurrentBorrowBalanceTH the current borrow balance of the user (before the borrow)
   * @param _userCurrentLtv the average ltv of the user given his current collateral
   * @return the total amount of collateral in ETH to cover the current borrow balance + the new amount + fee
   **/
  function calculateCollateralNeededInETH(
    address _reserve,
    uint256 _amount,
    uint256 _fee,
    uint256 _userCurrentBorrowBalanceTH,
    uint256 _userCurrentFeesETH,
    uint256 _userCurrentLtv
  ) external view returns (uint256) {
    uint256 reserveDecimals = core.getReserveDecimals(_reserve);

    IPriceOracleGetter oracle = IPriceOracleGetter(addressesProvider.getPriceOracle());

    uint256 requestedBorrowAmountETH = oracle.getAssetPrice(_reserve).mul(_amount.add(_fee)).div(
      10 ** reserveDecimals
    ); //price is in ether

    //add the current already borrowed amount to the amount requested to calculate the total collateral needed.
    uint256 collateralNeededInETH = _userCurrentBorrowBalanceTH
      .add(_userCurrentFeesETH)
      .add(requestedBorrowAmountETH)
      .mul(100)
      .div(_userCurrentLtv); //LTV is calculated in percentage

    return collateralNeededInETH;
  }

  /**
   * @dev calculates the equivalent amount in ETH that an user can borrow, depending on the available collateral and the
   * average Loan To Value.
   * @param collateralBalanceETH the total collateral balance
   * @param borrowBalanceETH the total borrow balance
   * @param totalFeesETH the total fees
   * @param ltv the average loan to value
   * @return the amount available to borrow in ETH for the user
   **/

  function calculateAvailableBorrowsETHInternal(
    uint256 collateralBalanceETH,
    uint256 borrowBalanceETH,
    uint256 totalFeesETH,
    uint256 ltv
  ) internal view returns (uint256) {
    uint256 availableBorrowsETH = collateralBalanceETH.mul(ltv).div(100); //ltv is in percentage

    if (availableBorrowsETH < borrowBalanceETH) {
      return 0;
    }

    availableBorrowsETH = availableBorrowsETH.sub(borrowBalanceETH.add(totalFeesETH));
    //calculate fee
    uint256 borrowFee = IFeeProvider(addressesProvider.getFeeProvider())
      .calculateLoanOriginationFee(msg.sender, availableBorrowsETH);
    return availableBorrowsETH.sub(borrowFee);
  }

  /**
   * @dev calculates the health factor from the corresponding balances
   * @param collateralBalanceETH the total collateral balance in ETH
   * @param borrowBalanceETH the total borrow balance in ETH
   * @param totalFeesETH the total fees in ETH
   * @param liquidationThreshold the avg liquidation threshold
   **/
  function calculateHealthFactorFromBalancesInternal(
    uint256 collateralBalanceETH,
    uint256 borrowBalanceETH,
    uint256 totalFeesETH,
    uint256 liquidationThreshold
  ) internal pure returns (uint256) {
    if (borrowBalanceETH == 0) return uint256(-1);

    return
      (collateralBalanceETH.mul(liquidationThreshold).div(100)).wadDiv(
        borrowBalanceETH.add(totalFeesETH)
      );
  }

  /**
   * @dev returns the health factor liquidation threshold
   **/
  function getHealthFactorLiquidationThreshold() public pure returns (uint256) {
    return HEALTH_FACTOR_LIQUIDATION_THRESHOLD;
  }

  /**
   * @dev accessory functions to fetch data from the lendingPoolCore
   **/
  function getReserveConfigurationData(
    address _reserve
  )
    external
    view
    returns (
      uint256 ltv,
      uint256 liquidationThreshold,
      uint256 liquidationBonus,
      address rateStrategyAddress,
      bool usageAsCollateralEnabled,
      bool borrowingEnabled,
      bool stableBorrowRateEnabled,
      bool isActive
    )
  {
    (, ltv, liquidationThreshold, usageAsCollateralEnabled) = core.getReserveConfiguration(
      _reserve
    );
    stableBorrowRateEnabled = core.getReserveIsStableBorrowRateEnabled(_reserve);
    borrowingEnabled = core.isReserveBorrowingEnabled(_reserve);
    isActive = core.getReserveIsActive(_reserve);
    liquidationBonus = core.getReserveLiquidationBonus(_reserve);

    rateStrategyAddress = core.getReserveInterestRateStrategyAddress(_reserve);
  }

  function getReserveData(
    address _reserve
  )
    external
    view
    returns (
      uint256 totalLiquidity,
      uint256 availableLiquidity,
      uint256 totalBorrowsStable,
      uint256 totalBorrowsVariable,
      uint256 liquidityRate,
      uint256 variableBorrowRate,
      uint256 stableBorrowRate,
      uint256 averageStableBorrowRate,
      uint256 utilizationRate,
      uint256 liquidityIndex,
      uint256 variableBorrowIndex,
      address aTokenAddress,
      uint40 lastUpdateTimestamp
    )
  {
    totalLiquidity = core.getReserveTotalLiquidity(_reserve);
    availableLiquidity = core.getReserveAvailableLiquidity(_reserve);
    totalBorrowsStable = core.getReserveTotalBorrowsStable(_reserve);
    totalBorrowsVariable = core.getReserveTotalBorrowsVariable(_reserve);
    liquidityRate = core.getReserveCurrentLiquidityRate(_reserve);
    variableBorrowRate = core.getReserveCurrentVariableBorrowRate(_reserve);
    stableBorrowRate = core.getReserveCurrentStableBorrowRate(_reserve);
    averageStableBorrowRate = core.getReserveCurrentAverageStableBorrowRate(_reserve);
    utilizationRate = core.getReserveUtilizationRate(_reserve);
    liquidityIndex = core.getReserveLiquidityCumulativeIndex(_reserve);
    variableBorrowIndex = core.getReserveVariableBorrowsCumulativeIndex(_reserve);
    aTokenAddress = core.getReserveATokenAddress(_reserve);
    lastUpdateTimestamp = core.getReserveLastUpdate(_reserve);
  }

  function getUserAccountData(
    address _user
  )
    external
    view
    returns (
      uint256 totalLiquidityETH,
      uint256 totalCollateralETH,
      uint256 totalBorrowsETH,
      uint256 totalFeesETH,
      uint256 availableBorrowsETH,
      uint256 currentLiquidationThreshold,
      uint256 ltv,
      uint256 healthFactor
    )
  {
    (
      totalLiquidityETH,
      totalCollateralETH,
      totalBorrowsETH,
      totalFeesETH,
      ltv,
      currentLiquidationThreshold,
      healthFactor,

    ) = calculateUserGlobalData(_user);

    availableBorrowsETH = calculateAvailableBorrowsETHInternal(
      totalCollateralETH,
      totalBorrowsETH,
      totalFeesETH,
      ltv
    );
  }

  function getUserReserveData(
    address _reserve,
    address _user
  )
    external
    view
    returns (
      uint256 currentATokenBalance,
      uint256 currentBorrowBalance,
      uint256 principalBorrowBalance,
      uint256 borrowRateMode,
      uint256 borrowRate,
      uint256 liquidityRate,
      uint256 originationFee,
      uint256 variableBorrowIndex,
      uint256 lastUpdateTimestamp,
      bool usageAsCollateralEnabled
    )
  {
    currentATokenBalance = AToken(core.getReserveATokenAddress(_reserve)).balanceOf(_user);
    CoreLibrary.InterestRateMode mode = core.getUserCurrentBorrowRateMode(_reserve, _user);
    (principalBorrowBalance, currentBorrowBalance, ) = core.getUserBorrowBalances(_reserve, _user);

    //default is 0, if mode == CoreLibrary.InterestRateMode.NONE
    if (mode == CoreLibrary.InterestRateMode.STABLE) {
      borrowRate = core.getUserCurrentStableBorrowRate(_reserve, _user);
    } else if (mode == CoreLibrary.InterestRateMode.VARIABLE) {
      borrowRate = core.getReserveCurrentVariableBorrowRate(_reserve);
    }

    borrowRateMode = uint256(mode);
    liquidityRate = core.getReserveCurrentLiquidityRate(_reserve);
    originationFee = core.getUserOriginationFee(_reserve, _user);
    variableBorrowIndex = core.getUserVariableBorrowCumulativeIndex(_reserve, _user);
    lastUpdateTimestamp = core.getUserLastUpdate(_reserve, _user);
    usageAsCollateralEnabled = core.isUserUseReserveAsCollateralEnabled(_reserve, _user);
  }
}

/**
 * @title Aave ERC20 AToken
 *
 * @dev Implementation of the interest bearing token for the DLP protocol.
 * @author Aave
 */
contract AToken is ERC20, ERC20Detailed {
  using WadRayMath for uint256;

  uint256 public constant UINT_MAX_VALUE = uint256(-1);

  /**
   * @dev emitted after the redeem action
   * @param _from the address performing the redeem
   * @param _value the amount to be redeemed
   * @param _fromBalanceIncrease the cumulated balance since the last update of the user
   * @param _fromIndex the last index of the user
   **/
  event Redeem(
    address indexed _from,
    uint256 _value,
    uint256 _fromBalanceIncrease,
    uint256 _fromIndex
  );

  /**
   * @dev emitted after the mint action
   * @param _from the address performing the mint
   * @param _value the amount to be minted
   * @param _fromBalanceIncrease the cumulated balance since the last update of the user
   * @param _fromIndex the last index of the user
   **/
  event MintOnDeposit(
    address indexed _from,
    uint256 _value,
    uint256 _fromBalanceIncrease,
    uint256 _fromIndex
  );

  /**
   * @dev emitted during the liquidation action, when the liquidator reclaims the underlying
   * asset
   * @param _from the address from which the tokens are being burned
   * @param _value the amount to be burned
   * @param _fromBalanceIncrease the cumulated balance since the last update of the user
   * @param _fromIndex the last index of the user
   **/
  event BurnOnLiquidation(
    address indexed _from,
    uint256 _value,
    uint256 _fromBalanceIncrease,
    uint256 _fromIndex
  );

  /**
   * @dev emitted during the transfer action
   * @param _from the address from which the tokens are being transferred
   * @param _to the adress of the destination
   * @param _value the amount to be minted
   * @param _fromBalanceIncrease the cumulated balance since the last update of the user
   * @param _toBalanceIncrease the cumulated balance since the last update of the destination
   * @param _fromIndex the last index of the user
   * @param _toIndex the last index of the liquidator
   **/
  event BalanceTransfer(
    address indexed _from,
    address indexed _to,
    uint256 _value,
    uint256 _fromBalanceIncrease,
    uint256 _toBalanceIncrease,
    uint256 _fromIndex,
    uint256 _toIndex
  );

  /**
   * @dev emitted when the accumulation of the interest
   * by an user is redirected to another user
   * @param _from the address from which the interest is being redirected
   * @param _to the adress of the destination
   * @param _fromBalanceIncrease the cumulated balance since the last update of the user
   * @param _fromIndex the last index of the user
   **/
  event InterestStreamRedirected(
    address indexed _from,
    address indexed _to,
    uint256 _redirectedBalance,
    uint256 _fromBalanceIncrease,
    uint256 _fromIndex
  );

  /**
   * @dev emitted when the redirected balance of an user is being updated
   * @param _targetAddress the address of which the balance is being updated
   * @param _targetBalanceIncrease the cumulated balance since the last update of the target
   * @param _targetIndex the last index of the user
   * @param _redirectedBalanceAdded the redirected balance being added
   * @param _redirectedBalanceRemoved the redirected balance being removed
   **/
  event RedirectedBalanceUpdated(
    address indexed _targetAddress,
    uint256 _targetBalanceIncrease,
    uint256 _targetIndex,
    uint256 _redirectedBalanceAdded,
    uint256 _redirectedBalanceRemoved
  );

  event InterestRedirectionAllowanceChanged(address indexed _from, address indexed _to);

  address public underlyingAssetAddress;

  mapping(address => uint256) private userIndexes;
  mapping(address => address) private interestRedirectionAddresses;
  mapping(address => uint256) private redirectedBalances;
  mapping(address => address) private interestRedirectionAllowances;

  LendingPoolAddressesProvider private addressesProvider;
  LendingPoolCore private core;
  LendingPool private pool;
  LendingPoolDataProvider private dataProvider;

  modifier onlyLendingPool() {
    require(msg.sender == address(pool), 'The caller of this function must be a lending pool');
    _;
  }

  modifier whenTransferAllowed(address _from, uint256 _amount) {
    require(isTransferAllowed(_from, _amount), 'Transfer cannot be allowed.');
    _;
  }

  constructor(
    LendingPoolAddressesProvider _addressesProvider,
    address _underlyingAsset,
    uint8 _underlyingAssetDecimals,
    string memory _name,
    string memory _symbol
  ) public ERC20Detailed(_name, _symbol, _underlyingAssetDecimals) {
    addressesProvider = _addressesProvider;
    core = LendingPoolCore(addressesProvider.getLendingPoolCore());
    pool = LendingPool(addressesProvider.getLendingPool());
    dataProvider = LendingPoolDataProvider(addressesProvider.getLendingPoolDataProvider());
    underlyingAssetAddress = _underlyingAsset;
  }

  /**
   * @notice ERC20 implementation internal function backing transfer() and transferFrom()
   * @dev validates the transfer before allowing it. NOTE: This is not standard ERC20 behavior
   **/
  function _transfer(
    address _from,
    address _to,
    uint256 _amount
  ) internal whenTransferAllowed(_from, _amount) {
    executeTransferInternal(_from, _to, _amount);
  }

  /**
   * @dev redirects the interest generated to a target address.
   * when the interest is redirected, the user balance is added to
   * the recepient redirected balance.
   * @param _to the address to which the interest will be redirected
   **/
  function redirectInterestStream(address _to) external {
    redirectInterestStreamInternal(msg.sender, _to);
  }

  /**
   * @dev redirects the interest generated by _from to a target address.
   * when the interest is redirected, the user balance is added to
   * the recepient redirected balance. The caller needs to have allowance on
   * the interest redirection to be able to execute the function.
   * @param _from the address of the user whom interest is being redirected
   * @param _to the address to which the interest will be redirected
   **/
  function redirectInterestStreamOf(address _from, address _to) external {
    require(
      msg.sender == interestRedirectionAllowances[_from],
      'Caller is not allowed to redirect the interest of the user'
    );
    redirectInterestStreamInternal(_from, _to);
  }

  /**
   * @dev gives allowance to an address to execute the interest redirection
   * on behalf of the caller.
   * @param _to the address to which the interest will be redirected. Pass address(0) to reset
   * the allowance.
   **/
  function allowInterestRedirectionTo(address _to) external {
    require(_to != msg.sender, 'User cannot give allowance to himself');
    interestRedirectionAllowances[msg.sender] = _to;
    emit InterestRedirectionAllowanceChanged(msg.sender, _to);
  }

  /**
   * @dev redeems aToken for the underlying asset
   * @param _amount the amount being redeemed
   **/
  function redeem(uint256 _amount) external {
    require(_amount > 0, 'Amount to redeem needs to be > 0');

    //cumulates the balance of the user
    (, uint256 currentBalance, uint256 balanceIncrease, uint256 index) = cumulateBalanceInternal(
      msg.sender
    );

    uint256 amountToRedeem = _amount;

    //if amount is equal to uint(-1), the user wants to redeem everything
    if (_amount == UINT_MAX_VALUE) {
      amountToRedeem = currentBalance;
    }

    require(amountToRedeem <= currentBalance, 'User cannot redeem more than the available balance');

    //check that the user is allowed to redeem the amount
    require(isTransferAllowed(msg.sender, amountToRedeem), 'Transfer cannot be allowed.');

    //if the user is redirecting his interest towards someone else,
    //we update the redirected balance of the redirection address by adding the accrued interest,
    //and removing the amount to redeem
    updateRedirectedBalanceOfRedirectionAddressInternal(
      msg.sender,
      balanceIncrease,
      amountToRedeem
    );

    // burns tokens equivalent to the amount requested
    _burn(msg.sender, amountToRedeem);

    bool userIndexReset = false;
    //reset the user data if the remaining balance is 0
    if (currentBalance.sub(amountToRedeem) == 0) {
      userIndexReset = resetDataOnZeroBalanceInternal(msg.sender);
    }

    // executes redeem of the underlying asset
    pool.redeemUnderlying(
      underlyingAssetAddress,
      msg.sender,
      amountToRedeem,
      currentBalance.sub(amountToRedeem)
    );

    emit Redeem(msg.sender, amountToRedeem, balanceIncrease, userIndexReset ? 0 : index);
  }

  /**
   * @dev mints token in the event of users depositing the underlying asset into the lending pool
   * only lending pools can call this function
   * @param _account the address receiving the minted tokens
   * @param _amount the amount of tokens to mint
   */
  function mintOnDeposit(address _account, uint256 _amount) external onlyLendingPool {
    //cumulates the balance of the user
    (, , uint256 balanceIncrease, uint256 index) = cumulateBalanceInternal(_account);

    //if the user is redirecting his interest towards someone else,
    //we update the redirected balance of the redirection address by adding the accrued interest
    //and the amount deposited
    updateRedirectedBalanceOfRedirectionAddressInternal(_account, balanceIncrease.add(_amount), 0);

    //mint an equivalent amount of tokens to cover the new deposit
    _mint(_account, _amount);

    emit MintOnDeposit(_account, _amount, balanceIncrease, index);
  }

  /**
   * @dev burns token in the event of a borrow being liquidated, in case the liquidators reclaims the underlying asset
   * Transfer of the liquidated asset is executed by the lending pool contract.
   * only lending pools can call this function
   * @param _account the address from which burn the aTokens
   * @param _value the amount to burn
   **/
  function burnOnLiquidation(address _account, uint256 _value) external onlyLendingPool {
    //cumulates the balance of the user being liquidated
    (, uint256 accountBalance, uint256 balanceIncrease, uint256 index) = cumulateBalanceInternal(
      _account
    );

    //adds the accrued interest and substracts the burned amount to
    //the redirected balance
    updateRedirectedBalanceOfRedirectionAddressInternal(_account, balanceIncrease, _value);

    //burns the requested amount of tokens
    _burn(_account, _value);

    bool userIndexReset = false;
    //reset the user data if the remaining balance is 0
    if (accountBalance.sub(_value) == 0) {
      userIndexReset = resetDataOnZeroBalanceInternal(_account);
    }

    emit BurnOnLiquidation(_account, _value, balanceIncrease, userIndexReset ? 0 : index);
  }

  /**
   * @dev transfers tokens in the event of a borrow being liquidated, in case the liquidators reclaims the aToken
   *      only lending pools can call this function
   * @param _from the address from which transfer the aTokens
   * @param _to the destination address
   * @param _value the amount to transfer
   **/
  function transferOnLiquidation(
    address _from,
    address _to,
    uint256 _value
  ) external onlyLendingPool {
    //being a normal transfer, the Transfer() and BalanceTransfer() are emitted
    //so no need to emit a specific event here
    executeTransferInternal(_from, _to, _value);
  }

  /**
   * @dev calculates the balance of the user, which is the
   * principal balance + interest generated by the principal balance + interest generated by the redirected balance
   * @param _user the user for which the balance is being calculated
   * @return the total balance of the user
   **/
  function balanceOf(address _user) public view returns (uint256) {
    //current principal balance of the user
    uint256 currentPrincipalBalance = super.balanceOf(_user);
    //balance redirected by other users to _user for interest rate accrual
    uint256 redirectedBalance = redirectedBalances[_user];

    if (currentPrincipalBalance == 0 && redirectedBalance == 0) {
      return 0;
    }
    //if the _user is not redirecting the interest to anybody, accrues
    //the interest for himself

    if (interestRedirectionAddresses[_user] == address(0)) {
      //accruing for himself means that both the principal balance and
      //the redirected balance partecipate in the interest
      return
        calculateCumulatedBalanceInternal(_user, currentPrincipalBalance.add(redirectedBalance))
          .sub(redirectedBalance);
    } else {
      //if the user redirected the interest, then only the redirected
      //balance generates interest. In that case, the interest generated
      //by the redirected balance is added to the current principal balance.
      return
        currentPrincipalBalance.add(
          calculateCumulatedBalanceInternal(_user, redirectedBalance).sub(redirectedBalance)
        );
    }
  }

  /**
   * @dev returns the principal balance of the user. The principal balance is the last
   * updated stored balance, which does not consider the perpetually accruing interest.
   * @param _user the address of the user
   * @return the principal balance of the user
   **/
  function principalBalanceOf(address _user) external view returns (uint256) {
    return super.balanceOf(_user);
  }

  /**
   * @dev calculates the total supply of the specific aToken
   * since the balance of every single user increases over time, the total supply
   * does that too.
   * @return the current total supply
   **/
  function totalSupply() public view returns (uint256) {
    uint256 currentSupplyPrincipal = super.totalSupply();

    if (currentSupplyPrincipal == 0) {
      return 0;
    }

    return
      currentSupplyPrincipal
        .wadToRay()
        .rayMul(core.getReserveNormalizedIncome(underlyingAssetAddress))
        .rayToWad();
  }

  /**
   * @dev Used to validate transfers before actually executing them.
   * @param _user address of the user to check
   * @param _amount the amount to check
   * @return true if the _user can transfer _amount, false otherwise
   **/
  function isTransferAllowed(address _user, uint256 _amount) public view returns (bool) {
    return dataProvider.balanceDecreaseAllowed(underlyingAssetAddress, _user, _amount);
  }

  /**
   * @dev returns the last index of the user, used to calculate the balance of the user
   * @param _user address of the user
   * @return the last user index
   **/
  function getUserIndex(address _user) external view returns (uint256) {
    return userIndexes[_user];
  }

  /**
   * @dev returns the address to which the interest is redirected
   * @param _user address of the user
   * @return 0 if there is no redirection, an address otherwise
   **/
  function getInterestRedirectionAddress(address _user) external view returns (address) {
    return interestRedirectionAddresses[_user];
  }

  /**
   * @dev returns the redirected balance of the user. The redirected balance is the balance
   * redirected by other accounts to the user, that is accrueing interest for him.
   * @param _user address of the user
   * @return the total redirected balance
   **/
  function getRedirectedBalance(address _user) external view returns (uint256) {
    return redirectedBalances[_user];
  }

  /**
   * @dev accumulates the accrued interest of the user to the principal balance
   * @param _user the address of the user for which the interest is being accumulated
   * @return the previous principal balance, the new principal balance, the balance increase
   * and the new user index
   **/
  function cumulateBalanceInternal(
    address _user
  ) internal returns (uint256, uint256, uint256, uint256) {
    uint256 previousPrincipalBalance = super.balanceOf(_user);

    //calculate the accrued interest since the last accumulation
    uint256 balanceIncrease = balanceOf(_user).sub(previousPrincipalBalance);
    //mints an amount of tokens equivalent to the amount accumulated
    _mint(_user, balanceIncrease);
    //updates the user index
    uint256 index = userIndexes[_user] = core.getReserveNormalizedIncome(underlyingAssetAddress);
    return (
      previousPrincipalBalance,
      previousPrincipalBalance.add(balanceIncrease),
      balanceIncrease,
      index
    );
  }

  /**
   * @dev updates the redirected balance of the user. If the user is not redirecting his
   * interest, nothing is executed.
   * @param _user the address of the user for which the interest is being accumulated
   * @param _balanceToAdd the amount to add to the redirected balance
   * @param _balanceToRemove the amount to remove from the redirected balance
   **/
  function updateRedirectedBalanceOfRedirectionAddressInternal(
    address _user,
    uint256 _balanceToAdd,
    uint256 _balanceToRemove
  ) internal {
    address redirectionAddress = interestRedirectionAddresses[_user];
    //if there isn't any redirection, nothing to be done
    if (redirectionAddress == address(0)) {
      return;
    }

    //compound balances of the redirected address
    (, , uint256 balanceIncrease, uint256 index) = cumulateBalanceInternal(redirectionAddress);

    //updating the redirected balance
    redirectedBalances[redirectionAddress] = redirectedBalances[redirectionAddress]
      .add(_balanceToAdd)
      .sub(_balanceToRemove);

    //if the interest of redirectionAddress is also being redirected, we need to update
    //the redirected balance of the redirection target by adding the balance increase
    address targetOfRedirectionAddress = interestRedirectionAddresses[redirectionAddress];

    if (targetOfRedirectionAddress != address(0)) {
      redirectedBalances[targetOfRedirectionAddress] = redirectedBalances[
        targetOfRedirectionAddress
      ].add(balanceIncrease);
    }

    emit RedirectedBalanceUpdated(
      redirectionAddress,
      balanceIncrease,
      index,
      _balanceToAdd,
      _balanceToRemove
    );
  }

  /**
   * @dev calculate the interest accrued by _user on a specific balance
   * @param _user the address of the user for which the interest is being accumulated
   * @param _balance the balance on which the interest is calculated
   * @return the interest rate accrued
   **/
  function calculateCumulatedBalanceInternal(
    address _user,
    uint256 _balance
  ) internal view returns (uint256) {
    return
      _balance
        .wadToRay()
        .rayMul(core.getReserveNormalizedIncome(underlyingAssetAddress))
        .rayDiv(userIndexes[_user])
        .rayToWad();
  }

  /**
   * @dev executes the transfer of aTokens, invoked by both _transfer() and
   *      transferOnLiquidation()
   * @param _from the address from which transfer the aTokens
   * @param _to the destination address
   * @param _value the amount to transfer
   **/
  function executeTransferInternal(address _from, address _to, uint256 _value) internal {
    require(_value > 0, 'Transferred amount needs to be greater than zero');

    //cumulate the balance of the sender
    (
      ,
      uint256 fromBalance,
      uint256 fromBalanceIncrease,
      uint256 fromIndex
    ) = cumulateBalanceInternal(_from);

    //cumulate the balance of the receiver
    (, , uint256 toBalanceIncrease, uint256 toIndex) = cumulateBalanceInternal(_to);

    //if the sender is redirecting his interest towards someone else,
    //adds to the redirected balance the accrued interest and removes the amount
    //being transferred
    updateRedirectedBalanceOfRedirectionAddressInternal(_from, fromBalanceIncrease, _value);

    //if the receiver is redirecting his interest towards someone else,
    //adds to the redirected balance the accrued interest and the amount
    //being transferred
    updateRedirectedBalanceOfRedirectionAddressInternal(_to, toBalanceIncrease.add(_value), 0);

    //performs the transfer
    super._transfer(_from, _to, _value);

    bool fromIndexReset = false;
    //reset the user data if the remaining balance is 0
    if (fromBalance.sub(_value) == 0) {
      fromIndexReset = resetDataOnZeroBalanceInternal(_from);
    }

    emit BalanceTransfer(
      _from,
      _to,
      _value,
      fromBalanceIncrease,
      toBalanceIncrease,
      fromIndexReset ? 0 : fromIndex,
      toIndex
    );
  }

  /**
   * @dev executes the redirection of the interest from one address to another.
   * immediately after redirection, the destination address will start to accrue interest.
   * @param _from the address from which transfer the aTokens
   * @param _to the destination address
   **/
  function redirectInterestStreamInternal(address _from, address _to) internal {
    address currentRedirectionAddress = interestRedirectionAddresses[_from];

    require(_to != currentRedirectionAddress, 'Interest is already redirected to the user');

    //accumulates the accrued interest to the principal
    (
      uint256 previousPrincipalBalance,
      uint256 fromBalance,
      uint256 balanceIncrease,
      uint256 fromIndex
    ) = cumulateBalanceInternal(_from);

    require(fromBalance > 0, 'Interest stream can only be redirected if there is a valid balance');

    //if the user is already redirecting the interest to someone, before changing
    //the redirection address we substract the redirected balance of the previous
    //recipient
    if (currentRedirectionAddress != address(0)) {
      updateRedirectedBalanceOfRedirectionAddressInternal(_from, 0, previousPrincipalBalance);
    }

    //if the user is redirecting the interest back to himself,
    //we simply set to 0 the interest redirection address
    if (_to == _from) {
      interestRedirectionAddresses[_from] = address(0);
      emit InterestStreamRedirected(_from, address(0), fromBalance, balanceIncrease, fromIndex);
      return;
    }

    //first set the redirection address to the new recipient
    interestRedirectionAddresses[_from] = _to;

    //adds the user balance to the redirected balance of the destination
    updateRedirectedBalanceOfRedirectionAddressInternal(_from, fromBalance, 0);

    emit InterestStreamRedirected(_from, _to, fromBalance, balanceIncrease, fromIndex);
  }

  /**
   * @dev function to reset the interest stream redirection and the user index, if the
   * user has no balance left.
   * @param _user the address of the user
   * @return true if the user index has also been reset, false otherwise. useful to emit the proper user index value
   **/
  function resetDataOnZeroBalanceInternal(address _user) internal returns (bool) {
    //if the user has 0 principal balance, the interest stream redirection gets reset
    interestRedirectionAddresses[_user] = address(0);

    //emits a InterestStreamRedirected event to notify that the redirection has been reset
    emit InterestStreamRedirected(_user, address(0), 0, 0, 0);

    //if the redirected balance is also 0, we clear up the user index
    if (redirectedBalances[_user] == 0) {
      userIndexes[_user] = 0;
      return true;
    } else {
      return false;
    }
  }
}

/**
 * @title IFlashLoanReceiver interface
 * @notice Interface for the Aave fee IFlashLoanReceiver.
 * @author Aave
 * @dev implement this interface to develop a flashloan-compatible flashLoanReceiver contract
 **/
interface IFlashLoanReceiver {
  function executeOperation(
    address _reserve,
    uint256 _amount,
    uint256 _fee,
    bytes calldata _params
  ) external;
}

/**
 * @title ILendingRateOracle interface
 * @notice Interface for the Aave borrow rate oracle. Provides the average market borrow rate to be used as a base for the stable borrow rate calculations
 **/

interface ILendingRateOracle {
  /**
    @dev returns the market borrow rate in ray
    **/
  function getMarketBorrowRate(address _asset) external view returns (uint256);

  /**
    @dev sets the market borrow rate. Rate value must be in ray
    **/
  function setMarketBorrowRate(address _asset, uint256 _rate) external;
}

/**
@title IReserveInterestRateStrategyInterface interface
@notice Interface for the calculation of the interest rates.
*/

interface IReserveInterestRateStrategy {
  /**
   * @dev returns the base variable borrow rate, in rays
   */

  function getBaseVariableBorrowRate() external view returns (uint256);

  /**
   * @dev calculates the liquidity, stable, and variable rates depending on the current utilization rate
   *      and the base parameters
   *
   */
  function calculateInterestRates(
    address _reserve,
    uint256 _utilizationRate,
    uint256 _totalBorrowsStable,
    uint256 _totalBorrowsVariable,
    uint256 _averageStableBorrowRate
  )
    external
    view
    returns (uint256 liquidityRate, uint256 stableBorrowRate, uint256 variableBorrowRate);
}

library EthAddressLib {
  /**
   * @dev returns the address used within the protocol to identify ETH
   * @return the address assigned to ETH
   */
  function ethAddress() internal pure returns (address) {
    return 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE;
  }
}

/**
 * @title LendingPool contract
 * @notice Implements the actions of the LendingPool, and exposes accessory methods to fetch the users and reserve data
 * @author Aave
 **/

contract LendingPool is ReentrancyGuard, VersionedInitializable {
  using SafeMath for uint256;
  using WadRayMath for uint256;
  using Address for address;
  using SafeERC20 for ERC20;

  LendingPoolAddressesProvider public addressesProvider;
  LendingPoolCore public core;
  LendingPoolDataProvider public dataProvider;
  LendingPoolParametersProvider public parametersProvider;
  IFeeProvider feeProvider;

  /**
   * @dev emitted on deposit
   * @param _reserve the address of the reserve
   * @param _user the address of the user
   * @param _amount the amount to be deposited
   * @param _referral the referral number of the action
   * @param _timestamp the timestamp of the action
   **/
  event Deposit(
    address indexed _reserve,
    address indexed _user,
    uint256 _amount,
    uint16 indexed _referral,
    uint256 _timestamp
  );

  /**
   * @dev emitted during a redeem action.
   * @param _reserve the address of the reserve
   * @param _user the address of the user
   * @param _amount the amount to be deposited
   * @param _timestamp the timestamp of the action
   **/
  event RedeemUnderlying(
    address indexed _reserve,
    address indexed _user,
    uint256 _amount,
    uint256 _timestamp
  );

  /**
   * @dev emitted on borrow
   * @param _reserve the address of the reserve
   * @param _user the address of the user
   * @param _amount the amount to be deposited
   * @param _borrowRateMode the rate mode, can be either 1-stable or 2-variable
   * @param _borrowRate the rate at which the user has borrowed
   * @param _originationFee the origination fee to be paid by the user
   * @param _borrowBalanceIncrease the balance increase since the last borrow, 0 if it's the first time borrowing
   * @param _referral the referral number of the action
   * @param _timestamp the timestamp of the action
   **/
  event Borrow(
    address indexed _reserve,
    address indexed _user,
    uint256 _amount,
    uint256 _borrowRateMode,
    uint256 _borrowRate,
    uint256 _originationFee,
    uint256 _borrowBalanceIncrease,
    uint16 indexed _referral,
    uint256 _timestamp
  );

  /**
   * @dev emitted on repay
   * @param _reserve the address of the reserve
   * @param _user the address of the user for which the repay has been executed
   * @param _repayer the address of the user that has performed the repay action
   * @param _amountMinusFees the amount repaid minus fees
   * @param _fees the fees repaid
   * @param _borrowBalanceIncrease the balance increase since the last action
   * @param _timestamp the timestamp of the action
   **/
  event Repay(
    address indexed _reserve,
    address indexed _user,
    address indexed _repayer,
    uint256 _amountMinusFees,
    uint256 _fees,
    uint256 _borrowBalanceIncrease,
    uint256 _timestamp
  );

  /**
   * @dev emitted when a user performs a rate swap
   * @param _reserve the address of the reserve
   * @param _user the address of the user executing the swap
   * @param _newRateMode the new interest rate mode
   * @param _newRate the new borrow rate
   * @param _borrowBalanceIncrease the balance increase since the last action
   * @param _timestamp the timestamp of the action
   **/
  event Swap(
    address indexed _reserve,
    address indexed _user,
    uint256 _newRateMode,
    uint256 _newRate,
    uint256 _borrowBalanceIncrease,
    uint256 _timestamp
  );

  /**
   * @dev emitted when a user enables a reserve as collateral
   * @param _reserve the address of the reserve
   * @param _user the address of the user
   **/
  event ReserveUsedAsCollateralEnabled(address indexed _reserve, address indexed _user);

  /**
   * @dev emitted when a user disables a reserve as collateral
   * @param _reserve the address of the reserve
   * @param _user the address of the user
   **/
  event ReserveUsedAsCollateralDisabled(address indexed _reserve, address indexed _user);

  /**
   * @dev emitted when the stable rate of a user gets rebalanced
   * @param _reserve the address of the reserve
   * @param _user the address of the user for which the rebalance has been executed
   * @param _newStableRate the new stable borrow rate after the rebalance
   * @param _borrowBalanceIncrease the balance increase since the last action
   * @param _timestamp the timestamp of the action
   **/
  event RebalanceStableBorrowRate(
    address indexed _reserve,
    address indexed _user,
    uint256 _newStableRate,
    uint256 _borrowBalanceIncrease,
    uint256 _timestamp
  );

  /**
   * @dev emitted when a flashloan is executed
   * @param _target the address of the flashLoanReceiver
   * @param _reserve the address of the reserve
   * @param _amount the amount requested
   * @param _totalFee the total fee on the amount
   * @param _protocolFee the part of the fee for the protocol
   * @param _timestamp the timestamp of the action
   **/
  event FlashLoan(
    address indexed _target,
    address indexed _reserve,
    uint256 _amount,
    uint256 _totalFee,
    uint256 _protocolFee,
    uint256 _timestamp
  );

  /**
   * @dev these events are not emitted directly by the LendingPool
   * but they are declared here as the LendingPoolLiquidationManager
   * is executed using a delegateCall().
   * This allows to have the events in the generated ABI for LendingPool.
   **/

  /**
   * @dev emitted when a borrow fee is liquidated
   * @param _collateral the address of the collateral being liquidated
   * @param _reserve the address of the reserve
   * @param _user the address of the user being liquidated
   * @param _feeLiquidated the total fee liquidated
   * @param _liquidatedCollateralForFee the amount of collateral received by the protocol in exchange for the fee
   * @param _timestamp the timestamp of the action
   **/
  event OriginationFeeLiquidated(
    address indexed _collateral,
    address indexed _reserve,
    address indexed _user,
    uint256 _feeLiquidated,
    uint256 _liquidatedCollateralForFee,
    uint256 _timestamp
  );

  /**
   * @dev emitted when a borrower is liquidated
   * @param _collateral the address of the collateral being liquidated
   * @param _reserve the address of the reserve
   * @param _user the address of the user being liquidated
   * @param _purchaseAmount the total amount liquidated
   * @param _liquidatedCollateralAmount the amount of collateral being liquidated
   * @param _accruedBorrowInterest the amount of interest accrued by the borrower since the last action
   * @param _liquidator the address of the liquidator
   * @param _receiveAToken true if the liquidator wants to receive aTokens, false otherwise
   * @param _timestamp the timestamp of the action
   **/
  event LiquidationCall(
    address indexed _collateral,
    address indexed _reserve,
    address indexed _user,
    uint256 _purchaseAmount,
    uint256 _liquidatedCollateralAmount,
    uint256 _accruedBorrowInterest,
    address _liquidator,
    bool _receiveAToken,
    uint256 _timestamp
  );

  /**
   * @dev Emitted during the token rescue
   * @param tokenRescued The token which is being rescued
   * @param receiver The recipient which will receive the rescued token
   * @param amountRescued The amount being rescued
   **/
  event TokensRescued(
    address indexed tokenRescued,
    address indexed receiver,
    uint256 amountRescued
  );

  /**
   * @dev functions affected by this modifier can only be invoked by the
   * aToken.sol contract
   * @param _reserve the address of the reserve
   **/
  modifier onlyOverlyingAToken(address _reserve) {
    require(
      msg.sender == core.getReserveATokenAddress(_reserve),
      'The caller of this function can only be the aToken contract of this reserve'
    );
    _;
  }

  /**
   * @dev functions affected by this modifier can only be invoked if the reserve is active
   * @param _reserve the address of the reserve
   **/
  modifier onlyActiveReserve(address _reserve) {
    requireReserveActiveInternal(_reserve);
    _;
  }

  /**
   * @dev functions affected by this modifier can only be invoked if the reserve is not freezed.
   * A freezed reserve only allows redeems, repays, rebalances and liquidations.
   * @param _reserve the address of the reserve
   **/
  modifier onlyUnfreezedReserve(address _reserve) {
    requireReserveNotFreezedInternal(_reserve);
    _;
  }

  /**
   * @dev functions affected by this modifier can only be invoked if the provided _amount input parameter
   * is not zero.
   * @param _amount the amount provided
   **/
  modifier onlyAmountGreaterThanZero(uint256 _amount) {
    requireAmountGreaterThanZeroInternal(_amount);
    _;
  }

  modifier onlyAddressesProviderOwner() {
    require(
      msg.sender == addressesProvider.owner(),
      'The caller of this function can only be the addressesProvider owner'
    );
    _;
  }

  uint256 public constant UINT_MAX_VALUE = uint256(-1);

  uint256 public constant LENDINGPOOL_REVISION = 0x8;

  function getRevision() internal pure returns (uint256) {
    return LENDINGPOOL_REVISION;
  }

  /**
   * @dev this function is invoked by the proxy contract when the LendingPool contract is added to the
   * AddressesProvider.
   * @param _addressesProvider the address of the LendingPoolAddressesProvider registry
   **/
  function initialize(LendingPoolAddressesProvider _addressesProvider) public initializer {
    addressesProvider = _addressesProvider;
    core = LendingPoolCore(addressesProvider.getLendingPoolCore());
    dataProvider = LendingPoolDataProvider(addressesProvider.getLendingPoolDataProvider());
    parametersProvider = LendingPoolParametersProvider(
      addressesProvider.getLendingPoolParametersProvider()
    );
    feeProvider = IFeeProvider(addressesProvider.getFeeProvider());
  }

  /**
   * @dev deposits The underlying asset into the reserve. A corresponding amount of the overlying asset (aTokens)
   * is minted.
   * @param _reserve the address of the reserve
   * @param _amount the amount to be deposited
   * @param _referralCode integrators are assigned a referral code and can potentially receive rewards.
   **/
  function deposit(
    address _reserve,
    uint256 _amount,
    uint16 _referralCode
  )
    external
    payable
    nonReentrant
    onlyActiveReserve(_reserve)
    onlyUnfreezedReserve(_reserve)
    onlyAmountGreaterThanZero(_amount)
  {
    require(false, 'METHOD_DISABLED');
  }

  /**
   * @dev Redeems the underlying amount of assets requested by _user.
   * This function is executed by the overlying aToken contract in response to a redeem action.
   * @param _reserve the address of the reserve
   * @param _user the address of the user performing the action
   * @param _amount the underlying amount to be redeemed
   **/
  function redeemUnderlying(
    address _reserve,
    address payable _user,
    uint256 _amount,
    uint256 _aTokenBalanceAfterRedeem
  )
    external
    nonReentrant
    onlyOverlyingAToken(_reserve)
    onlyActiveReserve(_reserve)
    onlyAmountGreaterThanZero(_amount)
  {
    uint256 currentAvailableLiquidity = core.getReserveAvailableLiquidity(_reserve);
    require(
      currentAvailableLiquidity >= _amount,
      'There is not enough liquidity available to redeem'
    );

    core.updateStateOnRedeem(_reserve, _user, _amount, _aTokenBalanceAfterRedeem == 0);

    core.transferToUser(_reserve, _user, _amount);

    //solium-disable-next-line
    emit RedeemUnderlying(_reserve, _user, _amount, block.timestamp);
  }

  /**
   * @dev data structures for local computations in the borrow() method.
   */

  struct BorrowLocalVars {
    uint256 principalBorrowBalance;
    uint256 currentLtv;
    uint256 currentLiquidationThreshold;
    uint256 borrowFee;
    uint256 requestedBorrowAmountETH;
    uint256 amountOfCollateralNeededETH;
    uint256 userCollateralBalanceETH;
    uint256 userBorrowBalanceETH;
    uint256 userTotalFeesETH;
    uint256 borrowBalanceIncrease;
    uint256 currentReserveStableRate;
    uint256 availableLiquidity;
    uint256 reserveDecimals;
    uint256 finalUserBorrowRate;
    CoreLibrary.InterestRateMode rateMode;
    bool healthFactorBelowThreshold;
  }

  /**
   * @dev Allows users to borrow a specific amount of the reserve currency, provided that the borrower
   * already deposited enough collateral.
   * @param _reserve the address of the reserve
   * @param _amount the amount to be borrowed
   * @param _interestRateMode the interest rate mode at which the user wants to borrow. Can be 0 (STABLE) or 1 (VARIABLE)
   **/
  function borrow(
    address _reserve,
    uint256 _amount,
    uint256 _interestRateMode,
    uint16 _referralCode
  )
    external
    nonReentrant
    onlyActiveReserve(_reserve)
    onlyUnfreezedReserve(_reserve)
    onlyAmountGreaterThanZero(_amount)
  {
    require(false, 'METHOD_DISABLED');
  }

  /**
   * @notice repays a borrow on the specific reserve, for the specified amount (or for the whole amount, if uint256(-1) is specified).
   * @dev the target user is defined by _onBehalfOf. If there is no repayment on behalf of another account,
   * _onBehalfOf must be equal to msg.sender.
   * @param _reserve the address of the reserve on which the user borrowed
   * @param _amount the amount to repay, or uint256(-1) if the user wants to repay everything
   * @param _onBehalfOf the address for which msg.sender is repaying.
   **/

  struct RepayLocalVars {
    uint256 principalBorrowBalance;
    uint256 compoundedBorrowBalance;
    uint256 borrowBalanceIncrease;
    bool isETH;
    uint256 paybackAmount;
    uint256 paybackAmountMinusFees;
    uint256 currentStableRate;
    uint256 originationFee;
  }

  function repay(
    address _reserve,
    uint256 _amount,
    address payable _onBehalfOf
  ) external payable nonReentrant onlyActiveReserve(_reserve) onlyAmountGreaterThanZero(_amount) {
    // Usage of a memory struct of vars to avoid "Stack too deep" errors due to local variables
    RepayLocalVars memory vars;

    (vars.principalBorrowBalance, vars.compoundedBorrowBalance, vars.borrowBalanceIncrease) = core
      .getUserBorrowBalances(_reserve, _onBehalfOf);

    vars.originationFee = core.getUserOriginationFee(_reserve, _onBehalfOf);
    vars.isETH = EthAddressLib.ethAddress() == _reserve;

    require(vars.compoundedBorrowBalance > 0, 'The user does not have any borrow pending');

    require(
      _amount != UINT_MAX_VALUE || msg.sender == _onBehalfOf,
      'To repay on behalf of an user an explicit amount to repay is needed.'
    );

    //default to max amount
    vars.paybackAmount = vars.compoundedBorrowBalance.add(vars.originationFee);

    if (_amount != UINT_MAX_VALUE && _amount < vars.paybackAmount) {
      vars.paybackAmount = _amount;
    }

    require(
      !vars.isETH || msg.value >= vars.paybackAmount,
      'Invalid msg.value sent for the repayment'
    );

    //if the amount is smaller than the origination fee, just transfer the amount to the fee destination address
    if (vars.paybackAmount <= vars.originationFee) {
      core.updateStateOnRepay(
        _reserve,
        _onBehalfOf,
        0,
        vars.paybackAmount,
        vars.borrowBalanceIncrease,
        false
      );

      core.transferToFeeCollectionAddress.value(vars.isETH ? vars.paybackAmount : 0)(
        _reserve,
        msg.sender,
        vars.paybackAmount,
        addressesProvider.getTokenDistributor()
      );

      emit Repay(
        _reserve,
        _onBehalfOf,
        msg.sender,
        0,
        vars.paybackAmount,
        vars.borrowBalanceIncrease,
        //solium-disable-next-line
        block.timestamp
      );
      return;
    }

    vars.paybackAmountMinusFees = vars.paybackAmount.sub(vars.originationFee);

    core.updateStateOnRepay(
      _reserve,
      _onBehalfOf,
      vars.paybackAmountMinusFees,
      vars.originationFee,
      vars.borrowBalanceIncrease,
      vars.compoundedBorrowBalance == vars.paybackAmountMinusFees
    );

    //if the user didn't repay the origination fee, transfer the fee to the fee collection address
    if (vars.originationFee > 0) {
      core.transferToFeeCollectionAddress.value(vars.isETH ? vars.originationFee : 0)(
        _reserve,
        msg.sender,
        vars.originationFee,
        addressesProvider.getTokenDistributor()
      );
    }

    //sending the total msg.value if the transfer is ETH.
    //the transferToReserve() function will take care of sending the
    //excess ETH back to the caller
    core.transferToReserve.value(vars.isETH ? msg.value.sub(vars.originationFee) : 0)(
      _reserve,
      msg.sender,
      vars.paybackAmountMinusFees
    );

    emit Repay(
      _reserve,
      _onBehalfOf,
      msg.sender,
      vars.paybackAmountMinusFees,
      vars.originationFee,
      vars.borrowBalanceIncrease,
      //solium-disable-next-line
      block.timestamp
    );
  }

  /**
   * @dev borrowers can user this function to swap between stable and variable borrow rate modes.
   * @param _reserve the address of the reserve on which the user borrowed
   **/
  function swapBorrowRateMode(
    address _reserve
  ) external nonReentrant onlyActiveReserve(_reserve) onlyUnfreezedReserve(_reserve) {
    require(false, 'METHOD_DISABLED');
  }

  /**
   * @dev rebalances the stable interest rate of a user if current liquidity rate > user stable rate.
   * this is regulated by Aave to ensure that the protocol is not abused, and the user is paying a fair
   * rate. The rebalance mechanism is updated in the context of the V1 -> V2 transition to automatically switch the user to variable.
   * @param _reserve the address of the reserve
   * @param _user the address of the user to be rebalanced
   **/
  function rebalanceStableBorrowRate(
    address _reserve,
    address _user
  ) external nonReentrant onlyActiveReserve(_reserve) {
    require(false, 'METHOD_DISABLED');
  }

  /**
   * @dev allows depositors to enable or disable a specific deposit as collateral.
   * @param _reserve the address of the reserve
   * @param _useAsCollateral true if the user wants to user the deposit as collateral, false otherwise.
   **/
  function setUserUseReserveAsCollateral(
    address _reserve,
    bool _useAsCollateral
  ) external nonReentrant onlyActiveReserve(_reserve) onlyUnfreezedReserve(_reserve) {
    require(false, 'METHOD_DISABLED');
  }

  /**
   * @dev users can invoke this function to liquidate an undercollateralized position.
   * This version has some important differences to the previous:
   * - a liquidator **can** liquidate up to 100% of the position
   * - a liquidator **can** liquidate healthy(collateralized) positions for a fixed 1% liquidationBonus
   * - a liquidator **can not** receive aTokens as the result of the liquidation
   * @param _reserve the address of the collateral to liquidated
   * @param _reserve the address of the principal reserve
   * @param _user the address of the borrower
   * @param _purchaseAmount the amount of principal that the liquidator wants to repay
   * @param _receiveAToken DEPRECATED not used anymore
   **/
  function liquidationCall(
    address _collateral,
    address _reserve,
    address _user,
    uint256 _purchaseAmount,
    bool _receiveAToken
  ) external payable nonReentrant onlyActiveReserve(_reserve) onlyActiveReserve(_collateral) {
    address liquidationManager = addressesProvider.getLendingPoolLiquidationManager();

    //solium-disable-next-line
    (bool success, bytes memory result) = liquidationManager.delegatecall(
      abi.encodeWithSignature(
        'liquidationCall(address,address,address,uint256)',
        _collateral,
        _reserve,
        _user,
        _purchaseAmount
      )
    );
    require(success, 'Liquidation call failed');

    (uint256 returnCode, string memory returnMessage) = abi.decode(result, (uint256, string));

    if (returnCode != 0) {
      //error found
      revert(string(abi.encodePacked('Liquidation failed: ', returnMessage)));
    }
  }

  /**
   * @dev allows smartcontracts to access the liquidity of the pool within one transaction,
   * as long as the amount taken plus a fee is returned. NOTE There are security concerns for developers of flashloan receiver contracts
   * that must be kept into consideration. For further details please visit https://developers.aave.com
   * @param _receiver The address of the contract receiving the funds. The receiver should implement the IFlashLoanReceiver interface.
   * @param _reserve the address of the principal reserve
   * @param _amount the amount requested for this flashloan
   **/
  function flashLoan(
    address _receiver,
    address _reserve,
    uint256 _amount,
    bytes memory _params
  ) public nonReentrant onlyActiveReserve(_reserve) onlyAmountGreaterThanZero(_amount) {
    require(false, 'METHOD_DISABLED');
  }

  function rescueTokens(
    address token,
    address to,
    uint256 amount
  ) external onlyAddressesProviderOwner {
    ERC20(token).safeTransfer(to, amount);
    emit TokensRescued(token, to, amount);
  }

  /**
   * @dev accessory functions to fetch data from the core contract
   **/

  function getReserveConfigurationData(
    address _reserve
  )
    external
    view
    returns (
      uint256 ltv,
      uint256 liquidationThreshold,
      uint256 liquidationBonus,
      address interestRateStrategyAddress,
      bool usageAsCollateralEnabled,
      bool borrowingEnabled,
      bool stableBorrowRateEnabled,
      bool isActive
    )
  {
    return dataProvider.getReserveConfigurationData(_reserve);
  }

  function getReserveData(
    address _reserve
  )
    external
    view
    returns (
      uint256 totalLiquidity,
      uint256 availableLiquidity,
      uint256 totalBorrowsStable,
      uint256 totalBorrowsVariable,
      uint256 liquidityRate,
      uint256 variableBorrowRate,
      uint256 stableBorrowRate,
      uint256 averageStableBorrowRate,
      uint256 utilizationRate,
      uint256 liquidityIndex,
      uint256 variableBorrowIndex,
      address aTokenAddress,
      uint40 lastUpdateTimestamp
    )
  {
    return dataProvider.getReserveData(_reserve);
  }

  function getUserAccountData(
    address _user
  )
    external
    view
    returns (
      uint256 totalLiquidityETH,
      uint256 totalCollateralETH,
      uint256 totalBorrowsETH,
      uint256 totalFeesETH,
      uint256 availableBorrowsETH,
      uint256 currentLiquidationThreshold,
      uint256 ltv,
      uint256 healthFactor
    )
  {
    return dataProvider.getUserAccountData(_user);
  }

  function getUserReserveData(
    address _reserve,
    address _user
  )
    external
    view
    returns (
      uint256 currentATokenBalance,
      uint256 currentBorrowBalance,
      uint256 principalBorrowBalance,
      uint256 borrowRateMode,
      uint256 borrowRate,
      uint256 liquidityRate,
      uint256 originationFee,
      uint256 variableBorrowIndex,
      uint256 lastUpdateTimestamp,
      bool usageAsCollateralEnabled
    )
  {
    return dataProvider.getUserReserveData(_reserve, _user);
  }

  function getReserves() external view returns (address[] memory) {
    return core.getReserves();
  }

  /**
   * @dev internal function to save on code size for the onlyActiveReserve modifier
   **/
  function requireReserveActiveInternal(address _reserve) internal view {
    require(core.getReserveIsActive(_reserve), 'Action requires an active reserve');
  }

  /**
   * @notice internal function to save on code size for the onlyUnfreezedReserve modifier
   **/
  function requireReserveNotFreezedInternal(address _reserve) internal view {
    require(!core.getReserveIsFreezed(_reserve), 'Action requires an unfreezed reserve');
  }

  /**
   * @notice internal function to save on code size for the onlyAmountGreaterThanZero modifier
   **/
  function requireAmountGreaterThanZeroInternal(uint256 _amount) internal pure {
    require(_amount > 0, 'Amount must be greater than 0');
  }
}

/**
 * @title LendingPoolCore contract
 * @author Aave
 * @notice Holds the state of the lending pool and all the funds deposited
 * @dev NOTE: The core does not enforce security checks on the update of the state
 * (eg, updateStateOnBorrow() does not enforce that borrowed is enabled on the reserve).
 * The check that an action can be performed is a duty of the overlying LendingPool contract.
 **/
contract LendingPoolCore is VersionedInitializable {
  using SafeMath for uint256;
  using WadRayMath for uint256;
  using CoreLibrary for CoreLibrary.ReserveData;
  using CoreLibrary for CoreLibrary.UserReserveData;
  using SafeERC20 for ERC20;
  using Address for address payable;

  /**
   * @dev Emitted when the state of a reserve is updated
   * @param reserve the address of the reserve
   * @param liquidityRate the new liquidity rate
   * @param stableBorrowRate the new stable borrow rate
   * @param variableBorrowRate the new variable borrow rate
   * @param liquidityIndex the new liquidity index
   * @param variableBorrowIndex the new variable borrow index
   **/
  event ReserveUpdated(
    address indexed reserve,
    uint256 liquidityRate,
    uint256 stableBorrowRate,
    uint256 variableBorrowRate,
    uint256 liquidityIndex,
    uint256 variableBorrowIndex
  );

  address public lendingPoolAddress;

  LendingPoolAddressesProvider public addressesProvider;

  /**
   * @dev only lending pools can use functions affected by this modifier
   **/
  modifier onlyLendingPool() {
    require(lendingPoolAddress == msg.sender, 'The caller must be a lending pool contract');
    _;
  }

  /**
   * @dev only lending pools configurator can use functions affected by this modifier
   **/
  modifier onlyLendingPoolConfigurator() {
    require(
      addressesProvider.getLendingPoolConfigurator() == msg.sender,
      'The caller must be a lending pool configurator contract'
    );
    _;
  }

  mapping(address => CoreLibrary.ReserveData) internal reserves;
  mapping(address => mapping(address => CoreLibrary.UserReserveData)) internal usersReserveData;

  address[] public reservesList;

  uint256 public constant CORE_REVISION = 0x8;

  /**
   * @dev returns the revision number of the contract
   **/
  function getRevision() internal pure returns (uint256) {
    return CORE_REVISION;
  }

  /**
   * @dev initializes the Core contract, invoked upon registration on the AddressesProvider
   * @param _addressesProvider the addressesProvider contract
   **/

  function initialize(LendingPoolAddressesProvider _addressesProvider) public initializer {
    addressesProvider = _addressesProvider;
    refreshConfigInternal();
  }

  /**
   * @dev updates the state of the core as a result of a deposit action
   * @param _reserve the address of the reserve in which the deposit is happening
   * @param _user the address of the the user depositing
   * @param _amount the amount being deposited
   * @param _isFirstDeposit true if the user is depositing for the first time
   **/

  function updateStateOnDeposit(
    address _reserve,
    address _user,
    uint256 _amount,
    bool _isFirstDeposit
  ) external onlyLendingPool {
    reserves[_reserve].updateCumulativeIndexes();
    updateReserveInterestRatesAndTimestampInternal(_reserve, _amount, 0);

    if (_isFirstDeposit) {
      //if this is the first deposit of the user, we configure the deposit as enabled to be used as collateral
      setUserUseReserveAsCollateral(_reserve, _user, true);
    }
  }

  /**
   * @dev updates the state of the core as a result of a redeem action
   * @param _reserve the address of the reserve in which the redeem is happening
   * @param _user the address of the the user redeeming
   * @param _amountRedeemed the amount being redeemed
   * @param _userRedeemedEverything true if the user is redeeming everything
   **/
  function updateStateOnRedeem(
    address _reserve,
    address _user,
    uint256 _amountRedeemed,
    bool _userRedeemedEverything
  ) external onlyLendingPool {
    //compound liquidity and variable borrow interests
    reserves[_reserve].updateCumulativeIndexes();
    updateReserveInterestRatesAndTimestampInternal(_reserve, 0, _amountRedeemed);

    //if user redeemed everything the useReserveAsCollateral flag is reset
    if (_userRedeemedEverything) {
      setUserUseReserveAsCollateral(_reserve, _user, false);
    }
  }

  /**
   * @dev updates the state of the core as a result of a flashloan action
   * @param _reserve the address of the reserve in which the flashloan is happening
   * @param _income the income of the protocol as a result of the action
   **/
  function updateStateOnFlashLoan(
    address _reserve,
    uint256 _availableLiquidityBefore,
    uint256 _income,
    uint256 _protocolFee
  ) external onlyLendingPool {
    transferFlashLoanProtocolFeeInternal(_reserve, _protocolFee);

    //compounding the cumulated interest
    reserves[_reserve].updateCumulativeIndexes();

    uint256 totalLiquidityBefore = _availableLiquidityBefore.add(getReserveTotalBorrows(_reserve));

    //compounding the received fee into the reserve
    reserves[_reserve].cumulateToLiquidityIndex(totalLiquidityBefore, _income);

    //refresh interest rates
    updateReserveInterestRatesAndTimestampInternal(_reserve, _income, 0);
  }

  /**
   * @dev updates the state of the core as a consequence of a borrow action.
   * @param _reserve the address of the reserve on which the user is borrowing
   * @param _user the address of the borrower
   * @param _amountBorrowed the new amount borrowed
   * @param _borrowFee the fee on the amount borrowed
   * @param _rateMode the borrow rate mode (stable, variable)
   * @return the new borrow rate for the user
   **/
  function updateStateOnBorrow(
    address _reserve,
    address _user,
    uint256 _amountBorrowed,
    uint256 _borrowFee,
    CoreLibrary.InterestRateMode _rateMode
  ) external onlyLendingPool returns (uint256, uint256) {
    // getting the previous borrow data of the user
    (uint256 principalBorrowBalance, , uint256 balanceIncrease) = getUserBorrowBalances(
      _reserve,
      _user
    );

    updateReserveStateOnBorrowInternal(
      _reserve,
      _user,
      principalBorrowBalance,
      balanceIncrease,
      _amountBorrowed,
      _rateMode
    );

    updateUserStateOnBorrowInternal(
      _reserve,
      _user,
      _amountBorrowed,
      balanceIncrease,
      _borrowFee,
      _rateMode
    );

    updateReserveInterestRatesAndTimestampInternal(_reserve, 0, _amountBorrowed);

    return (getUserCurrentBorrowRate(_reserve, _user), balanceIncrease);
  }

  /**
   * @dev updates the state of the core as a consequence of a repay action.
   * @param _reserve the address of the reserve on which the user is repaying
   * @param _user the address of the borrower
   * @param _paybackAmountMinusFees the amount being paid back minus fees
   * @param _originationFeeRepaid the fee on the amount that is being repaid
   * @param _balanceIncrease the accrued interest on the borrowed amount
   * @param _repaidWholeLoan true if the user is repaying the whole loan
   **/

  function updateStateOnRepay(
    address _reserve,
    address _user,
    uint256 _paybackAmountMinusFees,
    uint256 _originationFeeRepaid,
    uint256 _balanceIncrease,
    bool _repaidWholeLoan
  ) external onlyLendingPool {
    updateReserveStateOnRepayInternal(_reserve, _user, _paybackAmountMinusFees, _balanceIncrease);
    updateUserStateOnRepayInternal(
      _reserve,
      _user,
      _paybackAmountMinusFees,
      _originationFeeRepaid,
      _balanceIncrease,
      _repaidWholeLoan
    );

    updateReserveInterestRatesAndTimestampInternal(_reserve, _paybackAmountMinusFees, 0);
  }

  /**
   * @dev updates the state of the core as a consequence of a swap rate action.
   * @param _reserve the address of the reserve on which the user is repaying
   * @param _user the address of the borrower
   * @param _principalBorrowBalance the amount borrowed by the user
   * @param _compoundedBorrowBalance the amount borrowed plus accrued interest
   * @param _balanceIncrease the accrued interest on the borrowed amount
   * @param _currentRateMode the current interest rate mode for the user
   **/
  function updateStateOnSwapRate(
    address _reserve,
    address _user,
    uint256 _principalBorrowBalance,
    uint256 _compoundedBorrowBalance,
    uint256 _balanceIncrease,
    CoreLibrary.InterestRateMode _currentRateMode
  ) external onlyLendingPool returns (CoreLibrary.InterestRateMode, uint256) {
    updateReserveStateOnSwapRateInternal(
      _reserve,
      _user,
      _principalBorrowBalance,
      _compoundedBorrowBalance,
      _currentRateMode
    );

    CoreLibrary.InterestRateMode newRateMode = updateUserStateOnSwapRateInternal(
      _reserve,
      _user,
      _balanceIncrease,
      _currentRateMode
    );

    updateReserveInterestRatesAndTimestampInternal(_reserve, 0, 0);

    return (newRateMode, getUserCurrentBorrowRate(_reserve, _user));
  }

  /**
   * @dev updates the state of the core as a consequence of a liquidation action.
   * @param _principalReserve the address of the principal reserve that is being repaid
   * @param _collateralReserve the address of the collateral reserve that is being liquidated
   * @param _user the address of the borrower
   * @param _amountToLiquidate the amount being repaid by the liquidator
   * @param _collateralToLiquidate the amount of collateral being liquidated
   * @param _feeLiquidated the amount of origination fee being liquidated
   * @param _liquidatedCollateralForFee the amount of collateral equivalent to the origination fee + bonus
   * @param _balanceIncrease the accrued interest on the borrowed amount
   * @param _liquidatorReceivesAToken true if the liquidator will receive aTokens, false otherwise
   **/
  function updateStateOnLiquidation(
    address _principalReserve,
    address _collateralReserve,
    address _user,
    uint256 _amountToLiquidate,
    uint256 _collateralToLiquidate,
    uint256 _feeLiquidated,
    uint256 _liquidatedCollateralForFee,
    uint256 _balanceIncrease,
    bool _liquidatorReceivesAToken
  ) external onlyLendingPool {
    updatePrincipalReserveStateOnLiquidationInternal(
      _principalReserve,
      _user,
      _amountToLiquidate,
      _balanceIncrease
    );

    updateCollateralReserveStateOnLiquidationInternal(_collateralReserve);

    updateUserStateOnLiquidationInternal(
      _principalReserve,
      _user,
      _amountToLiquidate,
      _feeLiquidated,
      _balanceIncrease
    );

    updateReserveInterestRatesAndTimestampInternal(_principalReserve, _amountToLiquidate, 0);

    if (!_liquidatorReceivesAToken) {
      updateReserveInterestRatesAndTimestampInternal(
        _collateralReserve,
        0,
        _collateralToLiquidate.add(_liquidatedCollateralForFee)
      );
    }
  }

  /**
   * @dev updates the state of the core as a consequence of a stable rate rebalance
   * @param _reserve the address of the principal reserve where the user borrowed
   * @param _user the address of the borrower
   * @param _balanceIncrease the accrued interest on the borrowed amount
   * @return the new stable rate for the user
   **/
  function updateStateOnRebalance(
    address _reserve,
    address _user,
    uint256 _balanceIncrease
  ) external onlyLendingPool returns (uint256) {
    updateReserveStateOnRebalanceInternal(_reserve, _user, _balanceIncrease);

    //update user data and rebalance the rate
    updateUserStateOnRebalanceInternal(_reserve, _user, _balanceIncrease);
    updateReserveInterestRatesAndTimestampInternal(_reserve, 0, 0);
    return usersReserveData[_user][_reserve].stableBorrowRate;
  }

  /**
   * @dev enables or disables a reserve as collateral
   * @param _reserve the address of the principal reserve where the user deposited
   * @param _user the address of the depositor
   * @param _useAsCollateral true if the depositor wants to use the reserve as collateral
   **/
  function setUserUseReserveAsCollateral(
    address _reserve,
    address _user,
    bool _useAsCollateral
  ) public onlyLendingPool {
    CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];
    user.useAsCollateral = _useAsCollateral;
  }

  /**
   * @notice ETH/token transfer functions
   **/

  /**
   * @dev fallback function enforces that the caller is a contract, to support flashloan transfers
   **/
  function() external payable {
    //only contracts can send ETH to the core
    require(msg.sender.isContract(), 'Only contracts can send ether to the Lending pool core');
  }

  /**
   * @dev transfers to the user a specific amount from the reserve.
   * @param _reserve the address of the reserve where the transfer is happening
   * @param _user the address of the user receiving the transfer
   * @param _amount the amount being transferred
   **/
  function transferToUser(
    address _reserve,
    address payable _user,
    uint256 _amount
  ) external onlyLendingPool {
    if (_reserve != EthAddressLib.ethAddress()) {
      ERC20(_reserve).safeTransfer(_user, _amount);
    } else {
      //solium-disable-next-line
      (bool result, ) = _user.call.value(_amount).gas(50000)('');
      require(result, 'Transfer of ETH failed');
    }
  }

  /**
   * @dev transfers the protocol fees to the fees collection address
   * @param _token the address of the token being transferred
   * @param _user the address of the user from where the transfer is happening
   * @param _amount the amount being transferred
   * @param _destination the fee receiver address
   **/

  function transferToFeeCollectionAddress(
    address _token,
    address _user,
    uint256 _amount,
    address _destination
  ) external payable onlyLendingPool {
    address payable feeAddress = address(uint160(_destination)); //cast the address to payable

    if (_token != EthAddressLib.ethAddress()) {
      require(
        msg.value == 0,
        'User is sending ETH along with the ERC20 transfer. Check the value attribute of the transaction'
      );
      ERC20(_token).safeTransferFrom(_user, feeAddress, _amount);
    } else {
      require(msg.value >= _amount, 'The amount and the value sent to deposit do not match');
      //solium-disable-next-line
      (bool result, ) = feeAddress.call.value(_amount).gas(50000)('');
      require(result, 'Transfer of ETH failed');
    }
  }

  /**
   * @dev transfers the fees to the fees collection address in the case of liquidation
   * @param _token the address of the token being transferred
   * @param _amount the amount being transferred
   * @param _destination the fee receiver address
   **/
  function liquidateFee(
    address _token,
    uint256 _amount,
    address _destination
  ) external payable onlyLendingPool {
    address payable feeAddress = address(uint160(_destination)); //cast the address to payable
    require(msg.value == 0, 'Fee liquidation does not require any transfer of value');

    if (_token != EthAddressLib.ethAddress()) {
      ERC20(_token).safeTransfer(feeAddress, _amount);
    } else {
      //solium-disable-next-line
      (bool result, ) = feeAddress.call.value(_amount).gas(50000)('');
      require(result, 'Transfer of ETH failed');
    }
  }

  /**
   * @dev transfers an amount from a user to the destination reserve
   * @param _reserve the address of the reserve where the amount is being transferred
   * @param _user the address of the user from where the transfer is happening
   * @param _amount the amount being transferred
   **/
  function transferToReserve(
    address _reserve,
    address payable _user,
    uint256 _amount
  ) external payable onlyLendingPool {
    if (_reserve != EthAddressLib.ethAddress()) {
      require(msg.value == 0, 'User is sending ETH along with the ERC20 transfer.');
      ERC20(_reserve).safeTransferFrom(_user, address(this), _amount);
    } else {
      require(msg.value >= _amount, 'The amount and the value sent to deposit do not match');

      if (msg.value > _amount) {
        //send back excess ETH
        uint256 excessAmount = msg.value.sub(_amount);
        //solium-disable-next-line
        (bool result, ) = _user.call.value(excessAmount).gas(50000)('');
        require(result, 'Transfer of ETH failed');
      }
    }
  }

  /**
   * @notice data access functions
   **/

  /**
   * @dev returns the basic data (balances, fee accrued, reserve enabled/disabled as collateral)
   * needed to calculate the global account data in the LendingPoolDataProvider
   * @param _reserve the address of the reserve
   * @param _user the address of the user
   * @return the user deposited balance, the principal borrow balance, the fee, and if the reserve is enabled as collateral or not
   **/
  function getUserBasicReserveData(
    address _reserve,
    address _user
  ) external view returns (uint256, uint256, uint256, bool) {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];

    uint256 underlyingBalance = getUserUnderlyingAssetBalance(_reserve, _user);

    if (user.principalBorrowBalance == 0) {
      return (underlyingBalance, 0, 0, user.useAsCollateral);
    }

    return (
      underlyingBalance,
      user.getCompoundedBorrowBalance(reserve),
      user.originationFee,
      user.useAsCollateral
    );
  }

  /**
   * @dev checks if a user is allowed to borrow at a stable rate
   * @param _reserve the reserve address
   * @param _user the user
   * @param _amount the amount the the user wants to borrow
   * @return true if the user is allowed to borrow at a stable rate, false otherwise
   **/

  function isUserAllowedToBorrowAtStable(
    address _reserve,
    address _user,
    uint256 _amount
  ) external view returns (bool) {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];

    if (!reserve.isStableBorrowRateEnabled) return false;

    return
      !user.useAsCollateral ||
      !reserve.usageAsCollateralEnabled ||
      _amount > getUserUnderlyingAssetBalance(_reserve, _user);
  }

  /**
   * @dev gets the underlying asset balance of a user based on the corresponding aToken balance.
   * @param _reserve the reserve address
   * @param _user the user address
   * @return the underlying deposit balance of the user
   **/

  function getUserUnderlyingAssetBalance(
    address _reserve,
    address _user
  ) public view returns (uint256) {
    AToken aToken = AToken(reserves[_reserve].aTokenAddress);
    return aToken.balanceOf(_user);
  }

  /**
   * @dev gets the interest rate strategy contract address for the reserve
   * @param _reserve the reserve address
   * @return the address of the interest rate strategy contract
   **/
  function getReserveInterestRateStrategyAddress(address _reserve) public view returns (address) {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    return reserve.interestRateStrategyAddress;
  }

  /**
   * @dev gets the aToken contract address for the reserve
   * @param _reserve the reserve address
   * @return the address of the aToken contract
   **/

  function getReserveATokenAddress(address _reserve) public view returns (address) {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    return reserve.aTokenAddress;
  }

  /**
   * @dev gets the available liquidity in the reserve. The available liquidity is the balance of the core contract
   * @param _reserve the reserve address
   * @return the available liquidity
   **/
  function getReserveAvailableLiquidity(address _reserve) public view returns (uint256) {
    uint256 balance = 0;

    if (_reserve == EthAddressLib.ethAddress()) {
      balance = address(this).balance;
    } else {
      balance = IERC20(_reserve).balanceOf(address(this));
    }
    return balance;
  }

  /**
   * @dev gets the total liquidity in the reserve. The total liquidity is the balance of the core contract + total borrows
   * @param _reserve the reserve address
   * @return the total liquidity
   **/
  function getReserveTotalLiquidity(address _reserve) public view returns (uint256) {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    return getReserveAvailableLiquidity(_reserve).add(reserve.getTotalBorrows());
  }

  /**
   * @dev gets the normalized income of the reserve. a value of 1e27 means there is no income. A value of 2e27 means there
   * there has been 100% income.
   * @param _reserve the reserve address
   * @return the reserve normalized income
   **/
  function getReserveNormalizedIncome(address _reserve) external view returns (uint256) {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    return reserve.getNormalizedIncome();
  }

  /**
   * @dev gets the reserve total borrows
   * @param _reserve the reserve address
   * @return the total borrows (stable + variable)
   **/
  function getReserveTotalBorrows(address _reserve) public view returns (uint256) {
    return reserves[_reserve].getTotalBorrows();
  }

  /**
   * @dev gets the reserve total borrows stable
   * @param _reserve the reserve address
   * @return the total borrows stable
   **/
  function getReserveTotalBorrowsStable(address _reserve) external view returns (uint256) {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    return reserve.totalBorrowsStable;
  }

  /**
   * @dev gets the reserve total borrows variable
   * @param _reserve the reserve address
   * @return the total borrows variable
   **/

  function getReserveTotalBorrowsVariable(address _reserve) external view returns (uint256) {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    return reserve.totalBorrowsVariable;
  }

  /**
   * @dev gets the reserve liquidation threshold
   * @param _reserve the reserve address
   * @return the reserve liquidation threshold
   **/

  function getReserveLiquidationThreshold(address _reserve) external view returns (uint256) {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    return reserve.liquidationThreshold;
  }

  /**
   * @dev gets the reserve liquidation bonus
   * @param _reserve the reserve address
   * @return the reserve liquidation bonus
   **/

  function getReserveLiquidationBonus(address _reserve) external view returns (uint256) {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    return reserve.liquidationBonus;
  }

  /**
   * @dev gets the reserve current variable borrow rate. Is the base variable borrow rate if the reserve is empty
   * @param _reserve the reserve address
   * @return the reserve current variable borrow rate
   **/

  function getReserveCurrentVariableBorrowRate(address _reserve) external view returns (uint256) {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];

    if (reserve.currentVariableBorrowRate == 0) {
      return
        IReserveInterestRateStrategy(reserve.interestRateStrategyAddress)
          .getBaseVariableBorrowRate();
    }
    return reserve.currentVariableBorrowRate;
  }

  /**
   * @dev gets the reserve current stable borrow rate. Is the market rate if the reserve is empty
   * @param _reserve the reserve address
   * @return the reserve current stable borrow rate
   **/

  function getReserveCurrentStableBorrowRate(address _reserve) public view returns (uint256) {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    ILendingRateOracle oracle = ILendingRateOracle(addressesProvider.getLendingRateOracle());

    if (reserve.currentStableBorrowRate == 0) {
      //no stable rate borrows yet
      return oracle.getMarketBorrowRate(_reserve);
    }

    return reserve.currentStableBorrowRate;
  }

  /**
   * @dev gets the reserve average stable borrow rate. The average stable rate is the weighted average
   * of all the loans taken at stable rate.
   * @param _reserve the reserve address
   * @return the reserve current average borrow rate
   **/
  function getReserveCurrentAverageStableBorrowRate(
    address _reserve
  ) external view returns (uint256) {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    return reserve.currentAverageStableBorrowRate;
  }

  /**
   * @dev gets the reserve liquidity rate
   * @param _reserve the reserve address
   * @return the reserve liquidity rate
   **/
  function getReserveCurrentLiquidityRate(address _reserve) external view returns (uint256) {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    return reserve.currentLiquidityRate;
  }

  /**
   * @dev gets the reserve liquidity cumulative index
   * @param _reserve the reserve address
   * @return the reserve liquidity cumulative index
   **/
  function getReserveLiquidityCumulativeIndex(address _reserve) external view returns (uint256) {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    return reserve.lastLiquidityCumulativeIndex;
  }

  /**
   * @dev gets the reserve variable borrow index
   * @param _reserve the reserve address
   * @return the reserve variable borrow index
   **/
  function getReserveVariableBorrowsCumulativeIndex(
    address _reserve
  ) external view returns (uint256) {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    return reserve.lastVariableBorrowCumulativeIndex;
  }

  /**
   * @dev this function aggregates the configuration parameters of the reserve.
   * It's used in the LendingPoolDataProvider specifically to save gas, and avoid
   * multiple external contract calls to fetch the same data.
   * @param _reserve the reserve address
   * @return the reserve decimals
   * @return the base ltv as collateral
   * @return the liquidation threshold
   * @return if the reserve is used as collateral or not
   **/
  function getReserveConfiguration(
    address _reserve
  ) external view returns (uint256, uint256, uint256, bool) {
    uint256 decimals;
    uint256 baseLTVasCollateral;
    uint256 liquidationThreshold;
    bool usageAsCollateralEnabled;

    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    decimals = reserve.decimals;
    baseLTVasCollateral = reserve.baseLTVasCollateral;
    liquidationThreshold = reserve.liquidationThreshold;
    usageAsCollateralEnabled = reserve.usageAsCollateralEnabled;

    return (decimals, baseLTVasCollateral, liquidationThreshold, usageAsCollateralEnabled);
  }

  /**
   * @dev returns the decimals of the reserve
   * @param _reserve the reserve address
   * @return the reserve decimals
   **/
  function getReserveDecimals(address _reserve) external view returns (uint256) {
    return reserves[_reserve].decimals;
  }

  /**
   * @dev returns true if the reserve is enabled for borrowing
   * @param _reserve the reserve address
   * @return true if the reserve is enabled for borrowing, false otherwise
   **/

  function isReserveBorrowingEnabled(address _reserve) external view returns (bool) {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    return reserve.borrowingEnabled;
  }

  /**
   * @dev returns true if the reserve is enabled as collateral
   * @param _reserve the reserve address
   * @return true if the reserve is enabled as collateral, false otherwise
   **/

  function isReserveUsageAsCollateralEnabled(address _reserve) external view returns (bool) {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    return reserve.usageAsCollateralEnabled;
  }

  /**
   * @dev returns true if the stable rate is enabled on reserve
   * @param _reserve the reserve address
   * @return true if the stable rate is enabled on reserve, false otherwise
   **/
  function getReserveIsStableBorrowRateEnabled(address _reserve) external view returns (bool) {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    return reserve.isStableBorrowRateEnabled;
  }

  /**
   * @dev returns true if the reserve is active
   * @param _reserve the reserve address
   * @return true if the reserve is active, false otherwise
   **/
  function getReserveIsActive(address _reserve) external view returns (bool) {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    return reserve.isActive;
  }

  /**
   * @notice returns if a reserve is freezed
   * @param _reserve the reserve for which the information is needed
   * @return true if the reserve is freezed, false otherwise
   **/

  function getReserveIsFreezed(address _reserve) external view returns (bool) {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    return reserve.isFreezed;
  }

  /**
   * @notice returns the timestamp of the last action on the reserve
   * @param _reserve the reserve for which the information is needed
   * @return the last updated timestamp of the reserve
   **/

  function getReserveLastUpdate(address _reserve) external view returns (uint40 timestamp) {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    timestamp = reserve.lastUpdateTimestamp;
  }

  /**
   * @dev returns the utilization rate U of a specific reserve
   * @param _reserve the reserve for which the information is needed
   * @return the utilization rate in ray
   **/

  function getReserveUtilizationRate(address _reserve) public view returns (uint256) {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];

    uint256 totalBorrows = reserve.getTotalBorrows();

    if (totalBorrows == 0) {
      return 0;
    }

    uint256 availableLiquidity = getReserveAvailableLiquidity(_reserve);

    return totalBorrows.rayDiv(availableLiquidity.add(totalBorrows));
  }

  /**
   * @return the array of reserves configured on the core
   **/
  function getReserves() external view returns (address[] memory) {
    return reservesList;
  }

  /**
   * @param _reserve the address of the reserve for which the information is needed
   * @param _user the address of the user for which the information is needed
   * @return true if the user has chosen to use the reserve as collateral, false otherwise
   **/
  function isUserUseReserveAsCollateralEnabled(
    address _reserve,
    address _user
  ) external view returns (bool) {
    CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];
    return user.useAsCollateral;
  }

  /**
   * @param _reserve the address of the reserve for which the information is needed
   * @param _user the address of the user for which the information is needed
   * @return the origination fee for the user
   **/
  function getUserOriginationFee(address _reserve, address _user) external view returns (uint256) {
    CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];
    return user.originationFee;
  }

  /**
   * @dev users with no loans in progress have NONE as borrow rate mode
   * @param _reserve the address of the reserve for which the information is needed
   * @param _user the address of the user for which the information is needed
   * @return the borrow rate mode for the user,
   **/

  function getUserCurrentBorrowRateMode(
    address _reserve,
    address _user
  ) public view returns (CoreLibrary.InterestRateMode) {
    CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];

    if (user.principalBorrowBalance == 0) {
      return CoreLibrary.InterestRateMode.NONE;
    }

    return
      user.stableBorrowRate > 0
        ? CoreLibrary.InterestRateMode.STABLE
        : CoreLibrary.InterestRateMode.VARIABLE;
  }

  /**
   * @dev gets the current borrow rate of the user
   * @param _reserve the address of the reserve for which the information is needed
   * @param _user the address of the user for which the information is needed
   * @return the borrow rate for the user,
   **/
  function getUserCurrentBorrowRate(
    address _reserve,
    address _user
  ) internal view returns (uint256) {
    CoreLibrary.InterestRateMode rateMode = getUserCurrentBorrowRateMode(_reserve, _user);

    if (rateMode == CoreLibrary.InterestRateMode.NONE) {
      return 0;
    }

    return
      rateMode == CoreLibrary.InterestRateMode.STABLE
        ? usersReserveData[_user][_reserve].stableBorrowRate
        : reserves[_reserve].currentVariableBorrowRate;
  }

  /**
   * @dev the stable rate returned is 0 if the user is borrowing at variable or not borrowing at all
   * @param _reserve the address of the reserve for which the information is needed
   * @param _user the address of the user for which the information is needed
   * @return the user stable rate
   **/
  function getUserCurrentStableBorrowRate(
    address _reserve,
    address _user
  ) external view returns (uint256) {
    CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];
    return user.stableBorrowRate;
  }

  /**
   * @dev calculates and returns the borrow balances of the user
   * @param _reserve the address of the reserve
   * @param _user the address of the user
   * @return the principal borrow balance, the compounded balance and the balance increase since the last borrow/repay/swap/rebalance
   **/

  function getUserBorrowBalances(
    address _reserve,
    address _user
  ) public view returns (uint256, uint256, uint256) {
    CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];
    if (user.principalBorrowBalance == 0) {
      return (0, 0, 0);
    }

    uint256 principal = user.principalBorrowBalance;
    uint256 compoundedBalance = CoreLibrary.getCompoundedBorrowBalance(user, reserves[_reserve]);
    return (principal, compoundedBalance, compoundedBalance.sub(principal));
  }

  /**
   * @dev the variable borrow index of the user is 0 if the user is not borrowing or borrowing at stable
   * @param _reserve the address of the reserve for which the information is needed
   * @param _user the address of the user for which the information is needed
   * @return the variable borrow index for the user
   **/

  function getUserVariableBorrowCumulativeIndex(
    address _reserve,
    address _user
  ) external view returns (uint256) {
    CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];
    return user.lastVariableBorrowCumulativeIndex;
  }

  /**
   * @dev the variable borrow index of the user is 0 if the user is not borrowing or borrowing at stable
   * @param _reserve the address of the reserve for which the information is needed
   * @param _user the address of the user for which the information is needed
   * @return the variable borrow index for the user
   **/

  function getUserLastUpdate(
    address _reserve,
    address _user
  ) external view returns (uint256 timestamp) {
    CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];
    timestamp = user.lastUpdateTimestamp;
  }

  /**
   * @dev updates the lending pool core configuration
   **/
  function refreshConfiguration() external onlyLendingPoolConfigurator {
    refreshConfigInternal();
  }

  /**
   * @dev initializes a reserve
   * @param _reserve the address of the reserve
   * @param _aTokenAddress the address of the overlying aToken contract
   * @param _decimals the decimals of the reserve currency
   * @param _interestRateStrategyAddress the address of the interest rate strategy contract
   **/
  function initReserve(
    address _reserve,
    address _aTokenAddress,
    uint256 _decimals,
    address _interestRateStrategyAddress
  ) external onlyLendingPoolConfigurator {
    reserves[_reserve].init(_aTokenAddress, _decimals, _interestRateStrategyAddress);
    addReserveToListInternal(_reserve);
  }

  /**
   * @dev removes the last added reserve in the reservesList array
   * @param _reserveToRemove the address of the reserve
   **/
  function removeLastAddedReserve(address _reserveToRemove) external onlyLendingPoolConfigurator {
    address lastReserve = reservesList[reservesList.length - 1];

    require(
      lastReserve == _reserveToRemove,
      'Reserve being removed is different than the reserve requested'
    );

    //as we can't check if totalLiquidity is 0 (since the reserve added might not be an ERC20) we at least check that there is nothing borrowed
    require(
      getReserveTotalBorrows(lastReserve) == 0,
      'Cannot remove a reserve with liquidity deposited'
    );

    reserves[lastReserve].isActive = false;
    reserves[lastReserve].aTokenAddress = address(0);
    reserves[lastReserve].decimals = 0;
    reserves[lastReserve].lastLiquidityCumulativeIndex = 0;
    reserves[lastReserve].lastVariableBorrowCumulativeIndex = 0;
    reserves[lastReserve].borrowingEnabled = false;
    reserves[lastReserve].usageAsCollateralEnabled = false;
    reserves[lastReserve].baseLTVasCollateral = 0;
    reserves[lastReserve].liquidationThreshold = 0;
    reserves[lastReserve].liquidationBonus = 0;
    reserves[lastReserve].interestRateStrategyAddress = address(0);

    reservesList.pop();
  }

  /**
   * @dev updates the address of the interest rate strategy contract
   * @param _reserve the address of the reserve
   * @param _rateStrategyAddress the address of the interest rate strategy contract
   **/
  function setReserveInterestRateStrategyAddress(
    address _reserve,
    address _rateStrategyAddress
  ) external onlyLendingPoolConfigurator {
    updateReserveInterestRatesAndTimestampInternal(_reserve, 0, 0);
    reserves[_reserve].updateCumulativeIndexes();
    reserves[_reserve].interestRateStrategyAddress = _rateStrategyAddress;
    updateReserveInterestRatesAndTimestampInternal(_reserve, 0, 0);
  }

  /**
   * @dev enables borrowing on a reserve. Also sets the stable rate borrowing
   * @param _reserve the address of the reserve
   * @param _stableBorrowRateEnabled true if the stable rate needs to be enabled, false otherwise
   **/

  function enableBorrowingOnReserve(
    address _reserve,
    bool _stableBorrowRateEnabled
  ) external onlyLendingPoolConfigurator {
    reserves[_reserve].enableBorrowing(_stableBorrowRateEnabled);
  }

  /**
   * @dev disables borrowing on a reserve
   * @param _reserve the address of the reserve
   **/

  function disableBorrowingOnReserve(address _reserve) external onlyLendingPoolConfigurator {
    reserves[_reserve].disableBorrowing();
  }

  /**
   * @dev enables a reserve to be used as collateral
   * @param _reserve the address of the reserve
   **/
  function enableReserveAsCollateral(
    address _reserve,
    uint256 _baseLTVasCollateral,
    uint256 _liquidationThreshold,
    uint256 _liquidationBonus
  ) external onlyLendingPoolConfigurator {
    reserves[_reserve].enableAsCollateral(
      _baseLTVasCollateral,
      _liquidationThreshold,
      _liquidationBonus
    );
  }

  /**
   * @dev disables a reserve to be used as collateral
   * @param _reserve the address of the reserve
   **/
  function disableReserveAsCollateral(address _reserve) external onlyLendingPoolConfigurator {
    reserves[_reserve].disableAsCollateral();
  }

  /**
   * @dev enable the stable borrow rate mode on a reserve
   * @param _reserve the address of the reserve
   **/
  function enableReserveStableBorrowRate(address _reserve) external onlyLendingPoolConfigurator {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    reserve.isStableBorrowRateEnabled = true;
  }

  /**
   * @dev disable the stable borrow rate mode on a reserve
   * @param _reserve the address of the reserve
   **/
  function disableReserveStableBorrowRate(address _reserve) external onlyLendingPoolConfigurator {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    reserve.isStableBorrowRateEnabled = false;
  }

  /**
   * @dev activates a reserve
   * @param _reserve the address of the reserve
   **/
  function activateReserve(address _reserve) external onlyLendingPoolConfigurator {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];

    require(
      reserve.lastLiquidityCumulativeIndex > 0 && reserve.lastVariableBorrowCumulativeIndex > 0,
      'Reserve has not been initialized yet'
    );
    reserve.isActive = true;
  }

  /**
   * @dev deactivates a reserve
   * @param _reserve the address of the reserve
   **/
  function deactivateReserve(address _reserve) external onlyLendingPoolConfigurator {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    reserve.isActive = false;
  }

  /**
   * @notice allows the configurator to freeze the reserve.
   * A freezed reserve does not allow any action apart from repay, redeem, liquidationCall, rebalance.
   * @param _reserve the address of the reserve
   **/
  function freezeReserve(address _reserve) external onlyLendingPoolConfigurator {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    reserve.isFreezed = true;
  }

  /**
   * @notice allows the configurator to unfreeze the reserve. A unfreezed reserve allows any action to be executed.
   * @param _reserve the address of the reserve
   **/
  function unfreezeReserve(address _reserve) external onlyLendingPoolConfigurator {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    reserve.isFreezed = false;
  }

  /**
   * @notice allows the configurator to update the loan to value of a reserve
   * @param _reserve the address of the reserve
   * @param _ltv the new loan to value
   **/
  function setReserveBaseLTVasCollateral(
    address _reserve,
    uint256 _ltv
  ) external onlyLendingPoolConfigurator {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    reserve.baseLTVasCollateral = _ltv;
  }

  /**
   * @notice allows the configurator to update the liquidation threshold of a reserve
   * @param _reserve the address of the reserve
   * @param _threshold the new liquidation threshold
   **/
  function setReserveLiquidationThreshold(
    address _reserve,
    uint256 _threshold
  ) external onlyLendingPoolConfigurator {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    reserve.liquidationThreshold = _threshold;
  }

  /**
   * @notice allows the configurator to update the liquidation bonus of a reserve
   * @param _reserve the address of the reserve
   * @param _bonus the new liquidation bonus
   **/
  function setReserveLiquidationBonus(
    address _reserve,
    uint256 _bonus
  ) external onlyLendingPoolConfigurator {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    reserve.liquidationBonus = _bonus;
  }

  /**
   * @notice allows the configurator to update the reserve decimals
   * @param _reserve the address of the reserve
   * @param _decimals the decimals of the reserve
   **/
  function setReserveDecimals(
    address _reserve,
    uint256 _decimals
  ) external onlyLendingPoolConfigurator {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    reserve.decimals = _decimals;
  }

  /**
   * @notice internal functions
   **/

  /**
   * @dev updates the state of a reserve as a consequence of a borrow action.
   * @param _reserve the address of the reserve on which the user is borrowing
   * @param _user the address of the borrower
   * @param _principalBorrowBalance the previous borrow balance of the borrower before the action
   * @param _balanceIncrease the accrued interest of the user on the previous borrowed amount
   * @param _amountBorrowed the new amount borrowed
   * @param _rateMode the borrow rate mode (stable, variable)
   **/

  function updateReserveStateOnBorrowInternal(
    address _reserve,
    address _user,
    uint256 _principalBorrowBalance,
    uint256 _balanceIncrease,
    uint256 _amountBorrowed,
    CoreLibrary.InterestRateMode _rateMode
  ) internal {
    reserves[_reserve].updateCumulativeIndexes();

    //increasing reserve total borrows to account for the new borrow balance of the user
    //NOTE: Depending on the previous borrow mode, the borrows might need to be switched from variable to stable or vice versa

    updateReserveTotalBorrowsByRateModeInternal(
      _reserve,
      _user,
      _principalBorrowBalance,
      _balanceIncrease,
      _amountBorrowed,
      _rateMode
    );
  }

  /**
   * @dev updates the state of a user as a consequence of a borrow action.
   * @param _reserve the address of the reserve on which the user is borrowing
   * @param _user the address of the borrower
   * @param _amountBorrowed the amount borrowed
   * @param _balanceIncrease the accrued interest of the user on the previous borrowed amount
   * @param _rateMode the borrow rate mode (stable, variable)
   * @return the final borrow rate for the user. Emitted by the borrow() event
   **/

  function updateUserStateOnBorrowInternal(
    address _reserve,
    address _user,
    uint256 _amountBorrowed,
    uint256 _balanceIncrease,
    uint256 _fee,
    CoreLibrary.InterestRateMode _rateMode
  ) internal {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];

    if (_rateMode == CoreLibrary.InterestRateMode.STABLE) {
      //stable
      //reset the user variable index, and update the stable rate
      user.stableBorrowRate = reserve.currentStableBorrowRate;
      user.lastVariableBorrowCumulativeIndex = 0;
    } else if (_rateMode == CoreLibrary.InterestRateMode.VARIABLE) {
      //variable
      //reset the user stable rate, and store the new borrow index
      user.stableBorrowRate = 0;
      user.lastVariableBorrowCumulativeIndex = reserve.lastVariableBorrowCumulativeIndex;
    } else {
      revert('Invalid borrow rate mode');
    }
    //increase the principal borrows and the origination fee
    user.principalBorrowBalance = user.principalBorrowBalance.add(_amountBorrowed).add(
      _balanceIncrease
    );
    user.originationFee = user.originationFee.add(_fee);

    //solium-disable-next-line
    user.lastUpdateTimestamp = uint40(block.timestamp);
  }

  /**
   * @dev updates the state of the reserve as a consequence of a repay action.
   * @param _reserve the address of the reserve on which the user is repaying
   * @param _user the address of the borrower
   * @param _paybackAmountMinusFees the amount being paid back minus fees
   * @param _balanceIncrease the accrued interest on the borrowed amount
   **/

  function updateReserveStateOnRepayInternal(
    address _reserve,
    address _user,
    uint256 _paybackAmountMinusFees,
    uint256 _balanceIncrease
  ) internal {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];

    CoreLibrary.InterestRateMode borrowRateMode = getUserCurrentBorrowRateMode(_reserve, _user);

    //update the indexes
    reserves[_reserve].updateCumulativeIndexes();

    //compound the cumulated interest to the borrow balance and then subtracting the payback amount
    if (borrowRateMode == CoreLibrary.InterestRateMode.STABLE) {
      reserve.increaseTotalBorrowsStableAndUpdateAverageRate(
        _balanceIncrease,
        user.stableBorrowRate
      );
      reserve.decreaseTotalBorrowsStableAndUpdateAverageRate(
        _paybackAmountMinusFees,
        user.stableBorrowRate
      );
    } else {
      reserve.increaseTotalBorrowsVariable(_balanceIncrease);
      reserve.decreaseTotalBorrowsVariable(_paybackAmountMinusFees);
    }
  }

  /**
   * @dev updates the state of the user as a consequence of a repay action.
   * @param _reserve the address of the reserve on which the user is repaying
   * @param _user the address of the borrower
   * @param _paybackAmountMinusFees the amount being paid back minus fees
   * @param _originationFeeRepaid the fee on the amount that is being repaid
   * @param _balanceIncrease the accrued interest on the borrowed amount
   * @param _repaidWholeLoan true if the user is repaying the whole loan
   **/
  function updateUserStateOnRepayInternal(
    address _reserve,
    address _user,
    uint256 _paybackAmountMinusFees,
    uint256 _originationFeeRepaid,
    uint256 _balanceIncrease,
    bool _repaidWholeLoan
  ) internal {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];

    //update the user principal borrow balance, adding the cumulated interest and then subtracting the payback amount
    user.principalBorrowBalance = user.principalBorrowBalance.add(_balanceIncrease).sub(
      _paybackAmountMinusFees
    );
    user.lastVariableBorrowCumulativeIndex = reserve.lastVariableBorrowCumulativeIndex;

    //if the balance decrease is equal to the previous principal (user is repaying the whole loan)
    //and the rate mode is stable, we reset the interest rate mode of the user
    if (_repaidWholeLoan) {
      user.stableBorrowRate = 0;
      user.lastVariableBorrowCumulativeIndex = 0;
    }
    user.originationFee = user.originationFee.sub(_originationFeeRepaid);

    //solium-disable-next-line
    user.lastUpdateTimestamp = uint40(block.timestamp);
  }

  /**
   * @dev updates the state of the user as a consequence of a swap rate action.
   * @param _reserve the address of the reserve on which the user is performing the rate swap
   * @param _user the address of the borrower
   * @param _principalBorrowBalance the the principal amount borrowed by the user
   * @param _compoundedBorrowBalance the principal amount plus the accrued interest
   * @param _currentRateMode the rate mode at which the user borrowed
   **/
  function updateReserveStateOnSwapRateInternal(
    address _reserve,
    address _user,
    uint256 _principalBorrowBalance,
    uint256 _compoundedBorrowBalance,
    CoreLibrary.InterestRateMode _currentRateMode
  ) internal {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];

    //compounding reserve indexes
    reserve.updateCumulativeIndexes();

    if (_currentRateMode == CoreLibrary.InterestRateMode.STABLE) {
      uint256 userCurrentStableRate = user.stableBorrowRate;

      //swap to variable
      reserve.decreaseTotalBorrowsStableAndUpdateAverageRate(
        _principalBorrowBalance,
        userCurrentStableRate
      ); //decreasing stable from old principal balance
      reserve.increaseTotalBorrowsVariable(_compoundedBorrowBalance); //increase variable borrows
    } else if (_currentRateMode == CoreLibrary.InterestRateMode.VARIABLE) {
      //swap to stable
      uint256 currentStableRate = reserve.currentStableBorrowRate;
      reserve.decreaseTotalBorrowsVariable(_principalBorrowBalance);
      reserve.increaseTotalBorrowsStableAndUpdateAverageRate(
        _compoundedBorrowBalance,
        currentStableRate
      );
    } else {
      revert('Invalid rate mode received');
    }
  }

  /**
   * @dev updates the state of the user as a consequence of a swap rate action.
   * @param _reserve the address of the reserve on which the user is performing the swap
   * @param _user the address of the borrower
   * @param _balanceIncrease the accrued interest on the borrowed amount
   * @param _currentRateMode the current rate mode of the user
   **/

  function updateUserStateOnSwapRateInternal(
    address _reserve,
    address _user,
    uint256 _balanceIncrease,
    CoreLibrary.InterestRateMode _currentRateMode
  ) internal returns (CoreLibrary.InterestRateMode) {
    CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];

    CoreLibrary.InterestRateMode newMode = CoreLibrary.InterestRateMode.NONE;

    if (_currentRateMode == CoreLibrary.InterestRateMode.VARIABLE) {
      //switch to stable
      newMode = CoreLibrary.InterestRateMode.STABLE;
      user.stableBorrowRate = reserve.currentStableBorrowRate;
      user.lastVariableBorrowCumulativeIndex = 0;
    } else if (_currentRateMode == CoreLibrary.InterestRateMode.STABLE) {
      newMode = CoreLibrary.InterestRateMode.VARIABLE;
      user.stableBorrowRate = 0;
      user.lastVariableBorrowCumulativeIndex = reserve.lastVariableBorrowCumulativeIndex;
    } else {
      revert('Invalid interest rate mode received');
    }
    //compounding cumulated interest
    user.principalBorrowBalance = user.principalBorrowBalance.add(_balanceIncrease);
    //solium-disable-next-line
    user.lastUpdateTimestamp = uint40(block.timestamp);

    return newMode;
  }

  /**
   * @dev updates the state of the principal reserve as a consequence of a liquidation action.
   * @param _principalReserve the address of the principal reserve that is being repaid
   * @param _user the address of the borrower
   * @param _amountToLiquidate the amount being repaid by the liquidator
   * @param _balanceIncrease the accrued interest on the borrowed amount
   **/

  function updatePrincipalReserveStateOnLiquidationInternal(
    address _principalReserve,
    address _user,
    uint256 _amountToLiquidate,
    uint256 _balanceIncrease
  ) internal {
    CoreLibrary.ReserveData storage reserve = reserves[_principalReserve];
    CoreLibrary.UserReserveData storage user = usersReserveData[_user][_principalReserve];

    //update principal reserve data
    reserve.updateCumulativeIndexes();

    CoreLibrary.InterestRateMode borrowRateMode = getUserCurrentBorrowRateMode(
      _principalReserve,
      _user
    );

    if (borrowRateMode == CoreLibrary.InterestRateMode.STABLE) {
      //increase the total borrows by the compounded interest
      reserve.increaseTotalBorrowsStableAndUpdateAverageRate(
        _balanceIncrease,
        user.stableBorrowRate
      );

      //decrease by the actual amount to liquidate
      reserve.decreaseTotalBorrowsStableAndUpdateAverageRate(
        _amountToLiquidate,
        user.stableBorrowRate
      );
    } else {
      //increase the total borrows by the compounded interest
      reserve.increaseTotalBorrowsVariable(_balanceIncrease);

      //decrease by the actual amount to liquidate
      reserve.decreaseTotalBorrowsVariable(_amountToLiquidate);
    }
  }

  /**
   * @dev updates the state of the collateral reserve as a consequence of a liquidation action.
   * @param _collateralReserve the address of the collateral reserve that is being liquidated
   **/
  function updateCollateralReserveStateOnLiquidationInternal(address _collateralReserve) internal {
    //update collateral reserve
    reserves[_collateralReserve].updateCumulativeIndexes();
  }

  /**
   * @dev updates the state of the user being liquidated as a consequence of a liquidation action.
   * @param _reserve the address of the principal reserve that is being repaid
   * @param _user the address of the borrower
   * @param _amountToLiquidate the amount being repaid by the liquidator
   * @param _feeLiquidated the amount of origination fee being liquidated
   * @param _balanceIncrease the accrued interest on the borrowed amount
   **/
  function updateUserStateOnLiquidationInternal(
    address _reserve,
    address _user,
    uint256 _amountToLiquidate,
    uint256 _feeLiquidated,
    uint256 _balanceIncrease
  ) internal {
    CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    //first increase by the compounded interest, then decrease by the liquidated amount
    user.principalBorrowBalance = user.principalBorrowBalance.add(_balanceIncrease).sub(
      _amountToLiquidate
    );

    if (getUserCurrentBorrowRateMode(_reserve, _user) == CoreLibrary.InterestRateMode.VARIABLE) {
      user.lastVariableBorrowCumulativeIndex = reserve.lastVariableBorrowCumulativeIndex;
    }

    if (_feeLiquidated > 0) {
      user.originationFee = user.originationFee.sub(_feeLiquidated);
    }

    //solium-disable-next-line
    user.lastUpdateTimestamp = uint40(block.timestamp);
  }

  /**
   * @dev updates the state of the reserve as a consequence of a stable rate rebalance
   * DEPRECATED FOR THE V1 -> V2 migration
   * @param _reserve the address of the principal reserve where the user borrowed
   * @param _user the address of the borrower
   * @param _balanceIncrease the accrued interest on the borrowed amount
   **/

  function updateReserveStateOnRebalanceInternal(
    address _reserve,
    address _user,
    uint256 _balanceIncrease
  ) internal {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];

    reserve.updateCumulativeIndexes();

    reserve.increaseTotalBorrowsStableAndUpdateAverageRate(_balanceIncrease, user.stableBorrowRate);
  }

  /**
   * @dev updates the state of the user as a consequence of a stable rate rebalance
   * @param _reserve the address of the principal reserve where the user borrowed
   * @param _user the address of the borrower
   * @param _balanceIncrease the accrued interest on the borrowed amount
   **/

  function updateUserStateOnRebalanceInternal(
    address _reserve,
    address _user,
    uint256 _balanceIncrease
  ) internal {
    CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];

    user.principalBorrowBalance = user.principalBorrowBalance.add(_balanceIncrease);
    user.stableBorrowRate = reserve.currentStableBorrowRate;

    //solium-disable-next-line
    user.lastUpdateTimestamp = uint40(block.timestamp);
  }

  /**
   * @dev updates the state of the user as a consequence of a stable rate rebalance
   * @param _reserve the address of the principal reserve where the user borrowed
   * @param _user the address of the borrower
   * @param _balanceIncrease the accrued interest on the borrowed amount
   * @param _amountBorrowed the accrued interest on the borrowed amount
   **/
  function updateReserveTotalBorrowsByRateModeInternal(
    address _reserve,
    address _user,
    uint256 _principalBalance,
    uint256 _balanceIncrease,
    uint256 _amountBorrowed,
    CoreLibrary.InterestRateMode _newBorrowRateMode
  ) internal {
    CoreLibrary.InterestRateMode previousRateMode = getUserCurrentBorrowRateMode(_reserve, _user);
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];

    if (previousRateMode == CoreLibrary.InterestRateMode.STABLE) {
      CoreLibrary.UserReserveData storage user = usersReserveData[_user][_reserve];
      reserve.decreaseTotalBorrowsStableAndUpdateAverageRate(
        _principalBalance,
        user.stableBorrowRate
      );
    } else if (previousRateMode == CoreLibrary.InterestRateMode.VARIABLE) {
      reserve.decreaseTotalBorrowsVariable(_principalBalance);
    }

    uint256 newPrincipalAmount = _principalBalance.add(_balanceIncrease).add(_amountBorrowed);
    if (_newBorrowRateMode == CoreLibrary.InterestRateMode.STABLE) {
      reserve.increaseTotalBorrowsStableAndUpdateAverageRate(
        newPrincipalAmount,
        reserve.currentStableBorrowRate
      );
    } else if (_newBorrowRateMode == CoreLibrary.InterestRateMode.VARIABLE) {
      reserve.increaseTotalBorrowsVariable(newPrincipalAmount);
    } else {
      revert('Invalid new borrow rate mode');
    }
  }

  /**
   * @dev Updates the reserve current stable borrow rate Rf, the current variable borrow rate Rv and the current liquidity rate Rl.
   * Also updates the lastUpdateTimestamp value. Please refer to the whitepaper for further information.
   * @param _reserve the address of the reserve to be updated
   * @param _liquidityAdded the amount of liquidity added to the protocol (deposit or repay) in the previous action
   * @param _liquidityTaken the amount of liquidity taken from the protocol (redeem or borrow)
   **/

  function updateReserveInterestRatesAndTimestampInternal(
    address _reserve,
    uint256 _liquidityAdded,
    uint256 _liquidityTaken
  ) internal {
    CoreLibrary.ReserveData storage reserve = reserves[_reserve];
    (
      uint256 newLiquidityRate,
      uint256 newStableRate,
      uint256 newVariableRate
    ) = IReserveInterestRateStrategy(reserve.interestRateStrategyAddress).calculateInterestRates(
        _reserve,
        getReserveAvailableLiquidity(_reserve).add(_liquidityAdded).sub(_liquidityTaken),
        reserve.totalBorrowsStable,
        reserve.totalBorrowsVariable,
        reserve.currentAverageStableBorrowRate
      );

    reserve.currentLiquidityRate = newLiquidityRate;
    reserve.currentStableBorrowRate = newStableRate;
    reserve.currentVariableBorrowRate = newVariableRate;

    //solium-disable-next-line
    reserve.lastUpdateTimestamp = uint40(block.timestamp);

    emit ReserveUpdated(
      _reserve,
      newLiquidityRate,
      newStableRate,
      newVariableRate,
      reserve.lastLiquidityCumulativeIndex,
      reserve.lastVariableBorrowCumulativeIndex
    );
  }

  /**
   * @dev transfers to the protocol fees of a flashloan to the fees collection address
   * @param _token the address of the token being transferred
   * @param _amount the amount being transferred
   **/

  function transferFlashLoanProtocolFeeInternal(address _token, uint256 _amount) internal {
    address payable receiver = address(uint160(addressesProvider.getTokenDistributor()));

    if (_token != EthAddressLib.ethAddress()) {
      ERC20(_token).safeTransfer(receiver, _amount);
    } else {
      //solium-disable-next-line
      (bool result, ) = receiver.call.value(_amount)('');
      require(result, 'Transfer to token distributor failed');
    }
  }

  /**
   * @dev updates the internal configuration of the core
   **/
  function refreshConfigInternal() internal {
    lendingPoolAddress = addressesProvider.getLendingPool();
  }

  /**
   * @dev adds a reserve to the array of the reserves address
   **/
  function addReserveToListInternal(address _reserve) internal {
    bool reserveAlreadyAdded = false;
    for (uint256 i = 0; i < reservesList.length; i++)
      if (reservesList[i] == _reserve) {
        reserveAlreadyAdded = true;
      }
    if (!reserveAlreadyAdded) reservesList.push(_reserve);
  }
}