pragma solidity 0.6.12;

pragma experimental ABIEncoderV2;



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) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     */
    function sub(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        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-contracts/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) {
        return div(a, b, "SafeMath: division by zero");
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message 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,
        string memory errorMessage
    ) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0, errorMessage);
        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) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message 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,
        string memory errorMessage
    ) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
        // for accounts without code, i.e. `keccak256('')`
        bytes32 codehash;

            bytes32 accountHash
         = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly {
            codehash := extcodehash(account)
        }
        return (codehash != accountHash && codehash != 0x0);
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(
            address(this).balance >= amount,
            "Address: insufficient balance"
        );

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (bool success, ) = recipient.call{value: amount}("");
        require(
            success,
            "Address: unable to send value, recipient may have reverted"
        );
    }
}

/**
 * @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 IERC20;` 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 {
        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 callOptionalReturn(IERC20 token, bytes memory data) private {
        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"
            );
        }
    }
}

library DataTypes {
    // refer to the whitepaper, section 1.1 basic concepts for a formal description of these properties.
    struct ReserveData {
        //stores the reserve configuration
        ReserveConfigurationMap configuration;
        //the liquidity index. Expressed in ray
        uint128 liquidityIndex;
        //variable borrow index. Expressed in ray
        uint128 variableBorrowIndex;
        //the current supply rate. Expressed in ray
        uint128 currentLiquidityRate;
        //the current variable borrow rate. Expressed in ray
        uint128 currentVariableBorrowRate;
        //the current stable borrow rate. Expressed in ray
        uint128 currentStableBorrowRate;
        uint40 lastUpdateTimestamp;
        //tokens addresses
        address aTokenAddress;
        address stableDebtTokenAddress;
        address variableDebtTokenAddress;
        //address of the interest rate strategy
        address interestRateStrategyAddress;
        //the id of the reserve. Represents the position in the list of the active reserves
        uint8 id;
    }

    struct ReserveConfigurationMap {
        //bit 0-15: LTV
        //bit 16-31: Liq. threshold
        //bit 32-47: Liq. bonus
        //bit 48-55: Decimals
        //bit 56: Reserve is active
        //bit 57: reserve is frozen
        //bit 58: borrowing is enabled
        //bit 59: stable rate borrowing enabled
        //bit 60-63: reserved
        //bit 64-79: reserve factor
        uint256 data;
    }

    struct UserConfigurationMap {
        uint256 data;
    }

    enum InterestRateMode {NONE, STABLE, VARIABLE}
}


/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
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.
     *
     * IMPORTANT: 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
    );
}

interface IFlashLoanReceiver {
    function executeOperation(
        address[] calldata assets,
        uint256[] calldata amounts,
        uint256[] calldata premiums,
        address initiator,
        bytes calldata params
    ) external returns (bool);
}

/**
 * @title LendingPoolAddressesProvider contract
 * @dev Main registry of addresses part of or connected to the protocol, including permissioned roles
 * - Acting also as factory of proxies and admin of those, so with right to change its implementations
 * - Owned by the Aave Governance
 * @author Aave
 **/
interface ILendingPoolAddressesProvider {
    event LendingPoolUpdated(address indexed newAddress);
    event ConfigurationAdminUpdated(address indexed newAddress);
    event EmergencyAdminUpdated(address indexed newAddress);
    event LendingPoolConfiguratorUpdated(address indexed newAddress);
    event LendingPoolCollateralManagerUpdated(address indexed newAddress);
    event PriceOracleUpdated(address indexed newAddress);
    event LendingRateOracleUpdated(address indexed newAddress);
    event ProxyCreated(bytes32 id, address indexed newAddress);
    event AddressSet(bytes32 id, address indexed newAddress, bool hasProxy);

    function setAddress(bytes32 id, address newAddress) external;

    function setAddressAsProxy(bytes32 id, address impl) external;

    function getAddress(bytes32 id) external view returns (address);

    function getLendingPool() external view returns (address);

    function setLendingPoolImpl(address pool) external;

    function getLendingPoolConfigurator() external view returns (address);

    function setLendingPoolConfiguratorImpl(address configurator) external;

    function getLendingPoolCollateralManager() external view returns (address);

    function setLendingPoolCollateralManager(address manager) external;

    function getPoolAdmin() external view returns (address);

    function setPoolAdmin(address admin) external;

    function getEmergencyAdmin() external view returns (address);

    function setEmergencyAdmin(address admin) external;

    function getPriceOracle() external view returns (address);

    function setPriceOracle(address priceOracle) external;

    function getLendingRateOracle() external view returns (address);

    function setLendingRateOracle(address lendingRateOracle) external;
}

interface ILendingPool {
    /**
     * @dev Emitted on deposit()
     * @param reserve The address of the underlying asset of the reserve
     * @param user The address initiating the deposit
     * @param onBehalfOf The beneficiary of the deposit, receiving the aTokens
     * @param amount The amount deposited
     * @param referral The referral code used
     **/
    event Deposit(
        address indexed reserve,
        address user,
        address indexed onBehalfOf,
        uint256 amount,
        uint16 indexed referral
    );

    /**
     * @dev Emitted on withdraw()
     * @param reserve The address of the underlyng asset being withdrawn
     * @param user The address initiating the withdrawal, owner of aTokens
     * @param to Address that will receive the underlying
     * @param amount The amount to be withdrawn
     **/
    event Withdraw(
        address indexed reserve,
        address indexed user,
        address indexed to,
        uint256 amount
    );

    /**
     * @dev Emitted on borrow() and flashLoan() when debt needs to be opened
     * @param reserve The address of the underlying asset being borrowed
     * @param user The address of the user initiating the borrow(), receiving the funds on borrow() or just
     * initiator of the transaction on flashLoan()
     * @param onBehalfOf The address that will be getting the debt
     * @param amount The amount borrowed out
     * @param borrowRateMode The rate mode: 1 for Stable, 2 for Variable
     * @param borrowRate The numeric rate at which the user has borrowed
     * @param referral The referral code used
     **/
    event Borrow(
        address indexed reserve,
        address user,
        address indexed onBehalfOf,
        uint256 amount,
        uint256 borrowRateMode,
        uint256 borrowRate,
        uint16 indexed referral
    );

    /**
     * @dev Emitted on repay()
     * @param reserve The address of the underlying asset of the reserve
     * @param user The beneficiary of the repayment, getting his debt reduced
     * @param repayer The address of the user initiating the repay(), providing the funds
     * @param amount The amount repaid
     **/
    event Repay(
        address indexed reserve,
        address indexed user,
        address indexed repayer,
        uint256 amount
    );

    /**
     * @dev Emitted on swapBorrowRateMode()
     * @param reserve The address of the underlying asset of the reserve
     * @param user The address of the user swapping his rate mode
     * @param rateMode The rate mode that the user wants to swap to
     **/
    event Swap(address indexed reserve, address indexed user, uint256 rateMode);

    /**
     * @dev Emitted on setUserUseReserveAsCollateral()
     * @param reserve The address of the underlying asset of the reserve
     * @param user The address of the user enabling the usage as collateral
     **/
    event ReserveUsedAsCollateralEnabled(
        address indexed reserve,
        address indexed user
    );

    /**
     * @dev Emitted on setUserUseReserveAsCollateral()
     * @param reserve The address of the underlying asset of the reserve
     * @param user The address of the user enabling the usage as collateral
     **/
    event ReserveUsedAsCollateralDisabled(
        address indexed reserve,
        address indexed user
    );

    /**
     * @dev Emitted on rebalanceStableBorrowRate()
     * @param reserve The address of the underlying asset of the reserve
     * @param user The address of the user for which the rebalance has been executed
     **/
    event RebalanceStableBorrowRate(
        address indexed reserve,
        address indexed user
    );

    /**
     * @dev Emitted on flashLoan()
     * @param target The address of the flash loan receiver contract
     * @param initiator The address initiating the flash loan
     * @param asset The address of the asset being flash borrowed
     * @param amount The amount flash borrowed
     * @param premium The fee flash borrowed
     * @param referralCode The referral code used
     **/
    event FlashLoan(
        address indexed target,
        address indexed initiator,
        address indexed asset,
        uint256 amount,
        uint256 premium,
        uint16 referralCode
    );

    /**
     * @dev Emitted when the pause is triggered.
     */
    event Paused();

    /**
     * @dev Emitted when the pause is lifted.
     */
    event Unpaused();

    /**
     * @dev Emitted when a borrower is liquidated. This event is emitted by the LendingPool via
     * LendingPoolCollateral manager using a DELEGATECALL
     * This allows to have the events in the generated ABI for LendingPool.
     * @param collateralAsset The address of the underlying asset used as collateral, to receive as result of the liquidation
     * @param debtAsset The address of the underlying borrowed asset to be repaid with the liquidation
     * @param user The address of the borrower getting liquidated
     * @param debtToCover The debt amount of borrowed `asset` the liquidator wants to cover
     * @param liquidatedCollateralAmount The amount of collateral received by the liiquidator
     * @param liquidator The address of the liquidator
     * @param receiveAToken `true` if the liquidators wants to receive the collateral aTokens, `false` if he wants
     * to receive the underlying collateral asset directly
     **/
    event LiquidationCall(
        address indexed collateralAsset,
        address indexed debtAsset,
        address indexed user,
        uint256 debtToCover,
        uint256 liquidatedCollateralAmount,
        address liquidator,
        bool receiveAToken
    );

    /**
     * @dev Emitted when the state of a reserve is updated. NOTE: This event is actually declared
     * in the ReserveLogic library and emitted in the updateInterestRates() function. Since the function is internal,
     * the event will actually be fired by the LendingPool contract. The event is therefore replicated here so it
     * gets added to the LendingPool ABI
     * @param reserve The address of the underlying asset 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 ReserveDataUpdated(
        address indexed reserve,
        uint256 liquidityRate,
        uint256 stableBorrowRate,
        uint256 variableBorrowRate,
        uint256 liquidityIndex,
        uint256 variableBorrowIndex
    );

    /**
     * @dev Deposits an `amount` of underlying asset into the reserve, receiving in return overlying aTokens.
     * - E.g. User deposits 100 USDC and gets in return 100 aUSDC
     * @param asset The address of the underlying asset to deposit
     * @param amount The amount to be deposited
     * @param onBehalfOf The address that will receive the aTokens, same as msg.sender if the user
     *   wants to receive them on his own wallet, or a different address if the beneficiary of aTokens
     *   is a different wallet
     * @param referralCode Code used to register the integrator originating the operation, for potential rewards.
     *   0 if the action is executed directly by the user, without any middle-man
     **/
    function deposit(
        address asset,
        uint256 amount,
        address onBehalfOf,
        uint16 referralCode
    ) external;

    /**
     * @dev Withdraws an `amount` of underlying asset from the reserve, burning the equivalent aTokens owned
     * E.g. User has 100 aUSDC, calls withdraw() and receives 100 USDC, burning the 100 aUSDC
     * @param asset The address of the underlying asset to withdraw
     * @param amount The underlying amount to be withdrawn
     *   - Send the value type(uint256).max in order to withdraw the whole aToken balance
     * @param to Address that will receive the underlying, same as msg.sender if the user
     *   wants to receive it on his own wallet, or a different address if the beneficiary is a
     *   different wallet
     **/
    function withdraw(
        address asset,
        uint256 amount,
        address to
    ) external;

    /**
     * @dev Allows users to borrow a specific `amount` of the reserve underlying asset, provided that the borrower
     * already deposited enough collateral, or he was given enough allowance by a credit delegator on the
     * corresponding debt token (StableDebtToken or VariableDebtToken)
     * - E.g. User borrows 100 USDC passing as `onBehalfOf` his own address, receiving the 100 USDC in his wallet
     *   and 100 stable/variable debt tokens, depending on the `interestRateMode`
     * @param asset The address of the underlying asset to borrow
     * @param amount The amount to be borrowed
     * @param interestRateMode The interest rate mode at which the user wants to borrow: 1 for Stable, 2 for Variable
     * @param referralCode Code used to register the integrator originating the operation, for potential rewards.
     *   0 if the action is executed directly by the user, without any middle-man
     * @param onBehalfOf Address of the user who will receive the debt. Should be the address of the borrower itself
     * calling the function if he wants to borrow against his own collateral, or the address of the credit delegator
     * if he has been given credit delegation allowance
     **/
    function borrow(
        address asset,
        uint256 amount,
        uint256 interestRateMode,
        uint16 referralCode,
        address onBehalfOf
    ) external;

    /**
     * @notice Repays a borrowed `amount` on a specific reserve, burning the equivalent debt tokens owned
     * - E.g. User repays 100 USDC, burning 100 variable/stable debt tokens of the `onBehalfOf` address
     * @param asset The address of the borrowed underlying asset previously borrowed
     * @param amount The amount to repay
     * - Send the value type(uint256).max in order to repay the whole debt for `asset` on the specific `debtMode`
     * @param rateMode The interest rate mode at of the debt the user wants to repay: 1 for Stable, 2 for Variable
     * @param onBehalfOf Address of the user who will get his debt reduced/removed. Should be the address of the
     * user calling the function if he wants to reduce/remove his own debt, or the address of any other
     * other borrower whose debt should be removed
     **/
    function repay(
        address asset,
        uint256 amount,
        uint256 rateMode,
        address onBehalfOf
    ) external;

    /**
     * @dev Allows a borrower to swap his debt between stable and variable mode, or viceversa
     * @param asset The address of the underlying asset borrowed
     * @param rateMode The rate mode that the user wants to swap to
     **/
    function swapBorrowRateMode(address asset, uint256 rateMode) external;

    /**
     * @dev Rebalances the stable interest rate of a user to the current stable rate defined on the reserve.
     * - Users can be rebalanced if the following conditions are satisfied:
     *     1. Usage ratio is above 95%
     *     2. the current deposit APY is below REBALANCE_UP_THRESHOLD * maxVariableBorrowRate, which means that too much has been
     *        borrowed at a stable rate and depositors are not earning enough
     * @param asset The address of the underlying asset borrowed
     * @param user The address of the user to be rebalanced
     **/
    function rebalanceStableBorrowRate(address asset, address user) external;

    /**
     * @dev Allows depositors to enable/disable a specific deposited asset as collateral
     * @param asset The address of the underlying asset deposited
     * @param useAsCollateral `true` if the user wants to use the deposit as collateral, `false` otherwise
     **/
    function setUserUseReserveAsCollateral(address asset, bool useAsCollateral)
        external;

    /**
     * @dev Function to liquidate a non-healthy position collateral-wise, with Health Factor below 1
     * - The caller (liquidator) covers `debtToCover` amount of debt of the user getting liquidated, and receives
     *   a proportionally amount of the `collateralAsset` plus a bonus to cover market risk
     * @param collateralAsset The address of the underlying asset used as collateral, to receive as result of the liquidation
     * @param debtAsset The address of the underlying borrowed asset to be repaid with the liquidation
     * @param user The address of the borrower getting liquidated
     * @param debtToCover The debt amount of borrowed `asset` the liquidator wants to cover
     * @param receiveAToken `true` if the liquidators wants to receive the collateral aTokens, `false` if he wants
     * to receive the underlying collateral asset directly
     **/
    function liquidationCall(
        address collateralAsset,
        address debtAsset,
        address user,
        uint256 debtToCover,
        bool receiveAToken
    ) external;

    /**
     * @dev Allows smartcontracts to access the liquidity of the pool within one transaction,
     * as long as the amount taken plus a fee is returned.
     * IMPORTANT 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 receiverAddress The address of the contract receiving the funds, implementing the IFlashLoanReceiver interface
     * @param assets The addresses of the assets being flash-borrowed
     * @param amounts The amounts amounts being flash-borrowed
     * @param modes Types of the debt to open if the flash loan is not returned:
     *   0 -> Don't open any debt, just revert if funds can't be transferred from the receiver
     *   1 -> Open debt at stable rate for the value of the amount flash-borrowed to the `onBehalfOf` address
     *   2 -> Open debt at variable rate for the value of the amount flash-borrowed to the `onBehalfOf` address
     * @param onBehalfOf The address  that will receive the debt in the case of using on `modes` 1 or 2
     * @param params Variadic packed params to pass to the receiver as extra information
     * @param referralCode Code used to register the integrator originating the operation, for potential rewards.
     *   0 if the action is executed directly by the user, without any middle-man
     **/
    function flashLoan(
        address receiverAddress,
        address[] calldata assets,
        uint256[] calldata amounts,
        uint256[] calldata modes,
        address onBehalfOf,
        bytes calldata params,
        uint16 referralCode
    ) external;

    /**
     * @dev Returns the user account data across all the reserves
     * @param user The address of the user
     * @return totalCollateralETH the total collateral in ETH of the user
     * @return totalDebtETH the total debt in ETH of the user
     * @return availableBorrowsETH the borrowing power left of the user
     * @return currentLiquidationThreshold the liquidation threshold of the user
     * @return ltv the loan to value of the user
     * @return healthFactor the current health factor of the user
     **/
    function getUserAccountData(address user)
        external
        view
        returns (
            uint256 totalCollateralETH,
            uint256 totalDebtETH,
            uint256 availableBorrowsETH,
            uint256 currentLiquidationThreshold,
            uint256 ltv,
            uint256 healthFactor
        );

    function initReserve(
        address reserve,
        address aTokenAddress,
        address stableDebtAddress,
        address variableDebtAddress,
        address interestRateStrategyAddress
    ) external;

    function setReserveInterestRateStrategyAddress(
        address reserve,
        address rateStrategyAddress
    ) external;

    function setConfiguration(address reserve, uint256 configuration) external;

    /**
     * @dev Returns the configuration of the reserve
     * @param asset The address of the underlying asset of the reserve
     * @return The configuration of the reserve
     **/
    function getConfiguration(address asset)
        external
        view
        returns (DataTypes.ReserveConfigurationMap memory);

    /**
     * @dev Returns the configuration of the user across all the reserves
     * @param user The user address
     * @return The configuration of the user
     **/
    function getUserConfiguration(address user)
        external
        view
        returns (DataTypes.UserConfigurationMap memory);

    /**
     * @dev Returns the normalized income normalized income of the reserve
     * @param asset The address of the underlying asset of the reserve
     * @return The reserve's normalized income
     */
    function getReserveNormalizedIncome(address asset)
        external
        view
        returns (uint256);

    /**
     * @dev Returns the normalized variable debt per unit of asset
     * @param asset The address of the underlying asset of the reserve
     * @return The reserve normalized variable debt
     */
    function getReserveNormalizedVariableDebt(address asset)
        external
        view
        returns (uint256);

    /**
     * @dev Returns the state and configuration of the reserve
     * @param asset The address of the underlying asset of the reserve
     * @return The state of the reserve
     **/
    function getReserveData(address asset)
        external
        view
        returns (DataTypes.ReserveData memory);

    function finalizeTransfer(
        address asset,
        address from,
        address to,
        uint256 amount,
        uint256 balanceFromAfter,
        uint256 balanceToBefore
    ) external;

    function getReservesList() external view returns (address[] memory);

    function getAddressesProvider()
        external
        view
        returns (ILendingPoolAddressesProvider);

    function setPause(bool val) external;

    function paused() external view returns (bool);
}





abstract contract FlashLoanReceiverBase is IFlashLoanReceiver {
    using SafeERC20 for IERC20;
    using SafeMath for uint256;

    ILendingPoolAddressesProvider internal _addressesProvider;
    ILendingPool internal _lendingPool;

    constructor(ILendingPoolAddressesProvider provider) public {
        _addressesProvider = provider;
        _lendingPool = ILendingPool(
            ILendingPoolAddressesProvider(provider).getLendingPool()
        );
    }

    receive() external payable {}
}



interface IBank {
    function liquidateBorrow(
        address borrower,
        address underlyingBorrow,
        address underlyingCollateral,
        uint256 repayAmount
    ) external payable;

    function tokenOut(address token, uint256 amountOut) external;
}



interface IBankController {
    function getAccountLiquidity(address account)
        external
        view
        returns (uint256 liquidity, uint256 shortfall);
}



interface IUniswapRouter {
    function swapExactTokensForTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);

    function swapExactETHForTokens(
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable returns (uint256[] memory amounts);

    function swapExactTokensForETH(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);
}


interface IWeth {
    function deposit() external payable;

    function withdraw(uint256 wad) external;
}


interface IChiToken {
    function free(uint256 value) external returns (uint256);

    function freeUpTo(uint256 value) external returns (uint256);

    function freeFrom(address from, uint256 value) external returns (uint256);

    function freeFromUpTo(address from, uint256 value)
        external
        returns (uint256);
}


contract MyAaveFlashLoan is FlashLoanReceiverBase {
    using SafeMath for uint256;

    IBank public bank;

    IBankController public bankController;

    IUniswapRouter public router;

    IWeth public weth;

    IChiToken chi;

    address public borrower;

    address public underlyingBorrow;

    address public underlyingCollateral;

    uint256 public repayAmount;

    address public admin;

    address[] public path;

    modifier onlyAdmin {
        require(msg.sender == admin, "Admin required");
        _;
    }

    modifier discountCHI(uint256 amount) {
        if (amount == 0) {
            _;
        } else {
            uint256 gasStart = gasleft();
            _;
            uint256 gasSpent = 21000 +
                gasStart -
                gasleft() +
                16 *
                msg.data.length;
            chi.freeFromUpTo(
                msg.sender,
                (gasSpent + 14154) / 41947
            );
        }
    }

    constructor(ILendingPoolAddressesProvider _addressProvider)
        public
        FlashLoanReceiverBase(_addressProvider)
    {
        admin = msg.sender;
        bank = IBank(0xdE7B3b2Fe0E7b4925107615A5b199a4EB40D9ca9);
        bankController = IBankController(
            0x936E6490eD786FD0e0f0C1b1e4E1540b9D41F9eF
        );
        router = IUniswapRouter(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);
        weth = IWeth(0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2);
        chi = IChiToken(0x0000000000004946c0e9F43F4Dee607b0eF1fA1c);
    }

    struct ExecuteVars {
        bool isCollateralETH;
        uint256 collateralBefore;
        uint256 collateralAfter;
        uint256 delta;
    }

    /**
        This function is called after your contract has received the flash loaned amount
     */
    function executeOperation(
        address[] calldata assets,
        uint256[] calldata amounts,
        uint256[] calldata premiums,
        address initiator,
        bytes calldata params
    ) external override returns (bool) {
        //
        // This contract now has the funds requested.
        // Your logic goes here.
        //

        initiator;
        params;
        ExecuteVars memory vars;

        bool isBorrowETH = underlyingBorrow ==
            0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE;

        if (isBorrowETH) {
            weth.withdraw(repayAmount);
        } else {
            approveInternal(
                underlyingBorrow,
                address(bankController),
                uint256(-1)
            );
        }

        bank.liquidateBorrow{value: repayAmount}(
            borrower,
            underlyingBorrow,
            underlyingCollateral,
            repayAmount
        );

        vars.isCollateralETH =
            underlyingCollateral == 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE;
        vars.collateralBefore = vars.isCollateralETH
            ? address(this).balance
            : IERC20(underlyingCollateral).balanceOf(address(this));
        // token out fToken
        bank.tokenOut(underlyingCollateral, uint256(-1));

        vars.collateralAfter = vars.isCollateralETH
            ? address(this).balance
            : IERC20(underlyingCollateral).balanceOf(address(this));
        vars.delta = vars.collateralAfter - vars.collateralBefore;

        if (vars.isCollateralETH) {
            // eth
            // path : eth => token, collaterral => borrow
            router.swapExactETHForTokens{value: vars.delta}(
                0,
                path,
                address(this),
                block.timestamp + 300
            );
        } else {
            // erc 20
            approveInternal(underlyingCollateral, address(router), uint256(-1));
            if (isBorrowETH) {
                // path : erc20 => eth, collateral => borrow
                router.swapExactTokensForETH(
                    vars.delta,
                    0,
                    path,
                    address(this),
                    block.timestamp + 300
                );
            } else {
                // path : erc20 => erc20, collateral => borrow
                router.swapExactTokensForTokens(
                    vars.delta,
                    0,
                    path,
                    address(this),
                    block.timestamp + 300
                );
            }
        }

        uint256 repayToAaveAmount = amounts[0].add(premiums[0]);
        if (isBorrowETH) {
            weth.deposit{value: repayToAaveAmount}();
        }

        // At the end of your logic above, this contract owes
        // the flashloaned amounts + premiums.
        // Therefore ensure your contract has enough to repay
        // these amounts.

        // Approve the LendingPool contract allowance to *pull* the owed amount
        // for (uint256 i = 0; i < assets.length; i++) {
        // uint256 amountOwing = amounts[0].add(premiums[0]);
        // IERC20(assets[i]).approve(address(_lendingPool), amountOwing);
        approveInternal(assets[0], address(_lendingPool), repayToAaveAmount);
        // }

        // if (address(this).balance > 0) {
        //     msg.sender.transfer(address(this).balance.sub(repayToAaveAmount));
        // } else {
        //     IERC20(underlyingBorrow).transfer(
        //         msg.sender,
        //         IERC20(underlyingBorrow).balanceOf(address(this))
        //     );
        // }

        return true;
    }

    // if we borrow eth from aave, it's weth, not eth
    // _path is from collateral to borrow
    function myFlashLoanCall(
        address _borrower,
        address _underlyingBorrow,
        address _underlyingCollateral,
        uint256 _repayAmount,
        address[] memory _path,
        uint256 chiAmount
    ) public payable onlyAdmin discountCHI(chiAmount) {
        borrower = _borrower;
        underlyingBorrow = _underlyingBorrow;
        underlyingCollateral = _underlyingCollateral;
        repayAmount = _repayAmount;
        path = _path;

        (, uint256 shortfall) = bankController.getAccountLiquidity(_borrower);
        require(shortfall != 0, "Insufficient shortfall");

        address receiverAddress = address(this);

        bool isBorrowETH = underlyingBorrow ==
            0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE;

        address[] memory assets = new address[](1);
        assets[0] = isBorrowETH ? address(weth) : _underlyingBorrow;

        uint256[] memory amounts = new uint256[](1);
        amounts[0] = _repayAmount;

        // 0 = no debt, 1 = stable, 2 = variable
        uint256[] memory modes = new uint256[](1);
        modes[0] = 0;

        address onBehalfOf = address(this);
        bytes memory params = "";
        uint16 referralCode = 0;

        _lendingPool.flashLoan(
            receiverAddress,
            assets,
            amounts,
            modes,
            onBehalfOf,
            params,
            referralCode
        );
    }

    function approveInternal(
        address token,
        address target,
        uint256 amount
    ) internal {
        IERC20(token).approve(target, 0);
        IERC20(token).approve(target, amount);
    }

    function approve(
        address token,
        address target,
        uint256 amount
    ) public onlyAdmin {
        approveInternal(token, target, amount);
    }

    function withdrawERC20(address token) public onlyAdmin {
        IERC20(token).transfer(admin, IERC20(token).balanceOf(address(this)));
    }

    function withdrawETH() public onlyAdmin {
        payable(admin).transfer(address(this).balance);
    }

    function setRouter(address _router) public onlyAdmin {
        router = IUniswapRouter(_router);
    }
}