// File: contracts/credit/CreditAccount.sol



// SPDX-License-Identifier: BUSL-1.1
// Gearbox Protocol. Generalized leverage for DeFi protocols
// (c) Gearbox Holdings, 2021
pragma solidity ^0.7.4;

import {Initializable} from "@openzeppelin/contracts/proxy/Initializable.sol";

import {Address} from "@openzeppelin/contracts/utils/Address.sol";
import {Ownable} from "@openzeppelin/contracts/access/Ownable.sol";
import {IERC20} from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import {SafeERC20} from "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
import {ICreditAccount} from "../interfaces/ICreditAccount.sol";
import {Constants} from "../libraries/helpers/Constants.sol";
import {Errors} from "../libraries/helpers/Errors.sol";


/// @title Credit Account
/// @notice Implements generic credit account logic:
///   - Keeps token balances
///   - Stores general parameters: borrowed amount, cumulative index at open and block when it was initialized
///   - Approves tokens for 3rd party contracts
///   - Transfers assets
///   - Execute financial orders
///
///  More: https://dev.gearbox.fi/developers/credit/credit_account
contract CreditAccount is ICreditAccount, Initializable {
    using SafeERC20 for IERC20;
    using Address for address;

    address public override factory;

    // Keeps address of current credit Manager
    address public override creditManager;

    // Amount borrowed to this account
    uint256 public override borrowedAmount;

    // Cumulative index at credit account opening
    uint256 public override cumulativeIndexAtOpen;

    // Block number when it was initialised last time
    uint256 public override since;

    // Contract version
    uint constant public version = 1;

    /// @dev Restricts operation for current credit manager only
    modifier creditManagerOnly {
        require(msg.sender == creditManager, Errors.CA_CONNECTED_CREDIT_MANAGER_ONLY);
        _;
    }

    /// @dev Initialise used instead of constructor cause we use contract cloning
    function initialize() external override initializer {
        factory = msg.sender;
    }

    /// @dev Connects credit account to credit account address. Restricted to account factory (owner) only
    /// @param _creditManager Credit manager address
    function connectTo(
        address _creditManager,
        uint256 _borrowedAmount,
        uint256 _cumulativeIndexAtOpen
    ) external override {
        require(msg.sender == factory, Errors.CA_FACTORY_ONLY);
        creditManager = _creditManager; // T:[CA-7]
        borrowedAmount = _borrowedAmount; // T:[CA-3,7]
        cumulativeIndexAtOpen = _cumulativeIndexAtOpen; //  T:[CA-3,7]
        since = block.number; // T:[CA-7]
    }

    /// @dev Updates borrowed amount. Restricted for current credit manager only
    /// @param _borrowedAmount Amount which pool lent to credit account
    function updateParameters(uint256 _borrowedAmount, uint256 _cumulativeIndexAtOpen)
        external
        override
        creditManagerOnly // T:[CA-2]
    {
        borrowedAmount = _borrowedAmount; // T:[CA-4]
        cumulativeIndexAtOpen = _cumulativeIndexAtOpen;
    }

    /// @dev Approves token for 3rd party contract. Restricted for current credit manager only
    /// @param token ERC20 token for allowance
    /// @param swapContract Swap contract address
    function approveToken(address token, address swapContract)
        external
        override
        creditManagerOnly // T:[CA-2]
    {
        IERC20(token).safeApprove(swapContract, 0); // T:[CA-5]
        IERC20(token).safeApprove(swapContract, Constants.MAX_INT); // T:[CA-5]
    }

    /// @dev Removes allowance token for 3rd party contract. Restricted for factory only
    /// @param token ERC20 token for allowance
    /// @param targetContract Swap contract address
    function cancelAllowance(address token, address targetContract)
        external
        override
    {
        require(msg.sender == factory, Errors.CA_FACTORY_ONLY);
        IERC20(token).safeApprove(targetContract, 0);
    }

    /// @dev Transfers tokens from credit account to provided address. Restricted for current credit manager only
    /// @param token Token which should be transferred from credit account
    /// @param to Address of recipient
    /// @param amount Amount to be transferred
    function safeTransfer(
        address token,
        address to,
        uint256 amount
    )
        external
        override
        creditManagerOnly // T:[CA-2]
    {
        IERC20(token).safeTransfer(to, amount); // T:[CA-6]
    }

    /// @dev Executes financial order on 3rd party service. Restricted for current credit manager only
    /// @param destination Contract address which should be called
    /// @param data Call data which should be sent
    function execute(address destination, bytes memory data)
        external
        override
        creditManagerOnly
        returns (bytes memory)
    {
        return destination.functionCall(data); // T: [CM-48]
    }
}

// File: @openzeppelin/contracts/proxy/Initializable.sol



// SPDX-License-Identifier: MIT

// solhint-disable-next-line compiler-version
pragma solidity >=0.4.24 <0.8.0;

import "../utils/Address.sol";

/**
 * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
 * behind a proxy. Since a proxied contract can't have a constructor, it's common to move constructor logic to an
 * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
 * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
 *
 * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
 * possible by providing the encoded function call as the `_data` argument to {UpgradeableProxy-constructor}.
 *
 * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
 * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
 */
abstract contract Initializable {

    /**
     * @dev Indicates that the contract has been initialized.
     */
    bool private _initialized;

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

    /**
     * @dev Modifier to protect an initializer function from being invoked twice.
     */
    modifier initializer() {
        require(_initializing || _isConstructor() || !_initialized, "Initializable: contract is already initialized");

        bool isTopLevelCall = !_initializing;
        if (isTopLevelCall) {
            _initializing = true;
            _initialized = true;
        }

        _;

        if (isTopLevelCall) {
            _initializing = false;
        }
    }

    /// @dev Returns true if and only if the function is running in the constructor
    function _isConstructor() private view returns (bool) {
        return !Address.isContract(address(this));
    }
}

// File: @openzeppelin/contracts/utils/Address.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.2 <0.8.0;

/**
 * @dev Collection of functions related to the address type
 */
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) {
        // This method relies on 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 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");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain`call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
      return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.call{ value: value }(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.staticcall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// File: @openzeppelin/contracts/access/Ownable.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "../utils/Context.sol";
/**
 * @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.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

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

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

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

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the 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 virtual 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 virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @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);
}

// File: @openzeppelin/contracts/token/ERC20/SafeERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "./IERC20.sol";
import "../../math/SafeMath.sol";
import "../../utils/Address.sol";

/**
 * @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));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    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, "SafeERC20: decreased allowance below zero");
        _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. We use {Address.functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "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");
        }
    }
}

// File: contracts/interfaces/ICreditAccount.sol



// SPDX-License-Identifier: GPL-2.0-or-later
// Gearbox Protocol. Generalized leverage for DeFi protocols
// (c) Gearbox Holdings, 2021
pragma solidity ^0.7.4;


/// @title Reusable Credit Account interface
/// @notice Implements general credit account:
///   - Keeps token balances
///   - Keeps token balances
///   - Stores general parameters: borrowed amount, cumulative index at open and block when it was initialized
///   - Approves tokens for 3rd party contracts
///   - Transfers assets
///   - Execute financial orders
///
///  More: https://dev.gearbox.fi/developers/creditManager/vanillacreditAccount

interface ICreditAccount {
    /// @dev Initializes clone contract
    function initialize() external;

    /// @dev Connects credit account to credit manager
    /// @param _creditManager Credit manager address
    function connectTo(
        address _creditManager,
        uint256 _borrowedAmount,
        uint256 _cumulativeIndexAtOpen
    ) external;

    //    /// @dev Set general credit account parameters. Restricted to credit managers only
    //    /// @param _borrowedAmount Amount which pool lent to credit account
    //    /// @param _cumulativeIndexAtOpen Cumulative index at open. Uses for interest calculation
    //    function setGenericParameters(
    //
    //    ) external;

    /// @dev Updates borrowed amount. Restricted to credit managers only
    /// @param _borrowedAmount Amount which pool lent to credit account
    function updateParameters(
        uint256 _borrowedAmount,
        uint256 _cumulativeIndexAtOpen
    ) external;

    /// @dev Approves particular token for swap contract
    /// @param token ERC20 token for allowance
    /// @param swapContract Swap contract address
    function approveToken(address token, address swapContract) external;

    /// @dev Cancels allowance for particular contract
    /// @param token Address of token for allowance
    /// @param targetContract Address of contract to cancel allowance
    function cancelAllowance(address token, address targetContract) external;

    /// Transfers tokens from credit account to provided address. Restricted for pool calls only
    /// @param token Token which should be tranferred from credit account
    /// @param to Address of recipient
    /// @param amount Amount to be transferred
    function safeTransfer(
        address token,
        address to,
        uint256 amount
    ) external;

    /// @dev Returns borrowed amount
    function borrowedAmount() external view returns (uint256);

    /// @dev Returns cumulative index at time of opening credit account
    function cumulativeIndexAtOpen() external view returns (uint256);

    /// @dev Returns Block number when it was initialised last time
    function since() external view returns (uint256);

    /// @dev Address of last connected credit manager
    function creditManager() external view returns (address);

    /// @dev Address of last connected credit manager
    function factory() external view returns (address);

    /// @dev Executed financial order on 3rd party service. Restricted for pool calls only
    /// @param destination Contract address which should be called
    /// @param data Call data which should be sent
    function execute(address destination, bytes memory data)
        external
        returns (bytes memory);
}

// File: contracts/libraries/helpers/Constants.sol



// SPDX-License-Identifier: GPL-2.0-or-later
// Gearbox Protocol. Generalized leverage for DeFi protocols
// (c) Gearbox Holdings, 2021
pragma solidity ^0.7.4;

import {PercentageMath} from "../math/PercentageMath.sol";

library Constants {
    uint256 constant MAX_INT =
        0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff;

    // 25% of MAX_INT
    uint256 constant MAX_INT_4 =
        0x3fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff;

    // REWARD FOR LEAN DEPLOYMENT MINING
    uint256 constant ACCOUNT_CREATION_REWARD = 1e5;
    uint256 constant DEPLOYMENT_COST = 1e17;

    // FEE = 10%
    uint256 constant FEE_INTEREST = 1000; // 10%

    // FEE + LIQUIDATION_FEE 2%
    uint256 constant FEE_LIQUIDATION = 200;

    // Liquidation premium 5%
    uint256 constant LIQUIDATION_DISCOUNTED_SUM = 9500;

    // 100% - LIQUIDATION_FEE - LIQUIDATION_PREMIUM
    uint256 constant UNDERLYING_TOKEN_LIQUIDATION_THRESHOLD =
        LIQUIDATION_DISCOUNTED_SUM - FEE_LIQUIDATION;

    // Seconds in a year
    uint256 constant SECONDS_PER_YEAR = 365 days;
    uint256 constant SECONDS_PER_ONE_AND_HALF_YEAR = SECONDS_PER_YEAR * 3 /2;

    // 1e18
    uint256 constant RAY = 1e27;
    uint256 constant WAD = 1e18;

    // OPERATIONS
    uint8 constant OPERATION_CLOSURE = 1;
    uint8 constant OPERATION_REPAY = 2;
    uint8 constant OPERATION_LIQUIDATION = 3;

    // Decimals for leverage, so x4 = 4*LEVERAGE_DECIMALS for openCreditAccount function
    uint8 constant LEVERAGE_DECIMALS = 100;

    // Maximum withdraw fee for pool in percentage math format. 100 = 1%
    uint8 constant MAX_WITHDRAW_FEE = 100;

    uint256 constant CHI_THRESHOLD = 9950;
    uint256 constant HF_CHECK_INTERVAL_DEFAULT = 4;

    uint256 constant NO_SWAP = 0;
    uint256 constant UNISWAP_V2 = 1;
    uint256 constant UNISWAP_V3 = 2;
    uint256 constant CURVE_V1 = 3;
    uint256 constant LP_YEARN = 4;

    uint256 constant EXACT_INPUT = 1;
    uint256 constant EXACT_OUTPUT = 2;
}

// File: contracts/libraries/helpers/Errors.sol



// SPDX-License-Identifier: GPL-2.0-or-later
// Gearbox Protocol. Generalized leverage for DeFi protocols
// (c) Gearbox Holdings, 2021
pragma solidity ^0.7.4;


/// @title Errors library
library Errors {
    //
    // COMMON
    //

    string public constant ZERO_ADDRESS_IS_NOT_ALLOWED = "Z0";
    string public constant NOT_IMPLEMENTED = "NI";
    string public constant INCORRECT_PATH_LENGTH = "PL";
    string public constant INCORRECT_ARRAY_LENGTH = "CR";
    string public constant REGISTERED_CREDIT_ACCOUNT_MANAGERS_ONLY = "CP";
    string public constant REGISTERED_POOLS_ONLY = "RP";
    string public constant INCORRECT_PARAMETER = "IP";

    //
    // MATH
    //

    string public constant MATH_MULTIPLICATION_OVERFLOW = "M1";
    string public constant MATH_ADDITION_OVERFLOW = "M2";
    string public constant MATH_DIVISION_BY_ZERO = "M3";

    //
    // POOL
    //

    string public constant POOL_CONNECTED_CREDIT_MANAGERS_ONLY = "PS0";
    string public constant POOL_INCOMPATIBLE_CREDIT_ACCOUNT_MANAGER = "PS1";
    string public constant POOL_MORE_THAN_EXPECTED_LIQUIDITY_LIMIT = "PS2";
    string public constant POOL_INCORRECT_WITHDRAW_FEE = "SP3";
    string public constant POOL_CANT_ADD_CREDIT_MANAGER_TWICE = "PS4";

    //
    // CREDIT MANAGER
    //

    string public constant CM_NO_OPEN_ACCOUNT = "CM1";
    string
        public constant CM_ZERO_ADDRESS_OR_USER_HAVE_ALREADY_OPEN_CREDIT_ACCOUNT =
        "CM2";

    string public constant CM_INCORRECT_AMOUNT = "CM3";
    string public constant CM_CAN_LIQUIDATE_WITH_SUCH_HEALTH_FACTOR = "CM4";
    string public constant CM_CAN_UPDATE_WITH_SUCH_HEALTH_FACTOR = "CM5";
    string public constant CM_WETH_GATEWAY_ONLY = "CM6";
    string public constant CM_INCORRECT_PARAMS = "CM7";
    string public constant CM_INCORRECT_FEES = "CM8";
    string public constant CM_MAX_LEVERAGE_IS_TOO_HIGH = "CM9";
    string public constant CM_CANT_CLOSE_WITH_LOSS = "CMA";
    string public constant CM_TARGET_CONTRACT_iS_NOT_ALLOWED = "CMB";
    string public constant CM_TRANSFER_FAILED = "CMC";
    string public constant CM_INCORRECT_NEW_OWNER = "CME";

    //
    // ACCOUNT FACTORY
    //

    string public constant AF_CANT_CLOSE_CREDIT_ACCOUNT_IN_THE_SAME_BLOCK =
        "AF1";
    string public constant AF_MINING_IS_FINISHED = "AF2";
    string public constant AF_CREDIT_ACCOUNT_NOT_IN_STOCK = "AF3";
    string public constant AF_EXTERNAL_ACCOUNTS_ARE_FORBIDDEN = "AF4";

    //
    // ADDRESS PROVIDER
    //

    string public constant AS_ADDRESS_NOT_FOUND = "AP1";

    //
    // CONTRACTS REGISTER
    //

    string public constant CR_POOL_ALREADY_ADDED = "CR1";
    string public constant CR_CREDIT_MANAGER_ALREADY_ADDED = "CR2";

    //
    // CREDIT_FILTER
    //

    string public constant CF_UNDERLYING_TOKEN_FILTER_CONFLICT = "CF0";
    string public constant CF_INCORRECT_LIQUIDATION_THRESHOLD = "CF1";
    string public constant CF_TOKEN_IS_NOT_ALLOWED = "CF2";
    string public constant CF_CREDIT_MANAGERS_ONLY = "CF3";
    string public constant CF_ADAPTERS_ONLY = "CF4";
    string public constant CF_OPERATION_LOW_HEALTH_FACTOR = "CF5";
    string public constant CF_TOO_MUCH_ALLOWED_TOKENS = "CF6";
    string public constant CF_INCORRECT_CHI_THRESHOLD = "CF7";
    string public constant CF_INCORRECT_FAST_CHECK = "CF8";
    string public constant CF_NON_TOKEN_CONTRACT = "CF9";
    string public constant CF_CONTRACT_IS_NOT_IN_ALLOWED_LIST = "CFA";
    string public constant CF_FAST_CHECK_NOT_COVERED_COLLATERAL_DROP = "CFB";
    string public constant CF_SOME_LIQUIDATION_THRESHOLD_MORE_THAN_NEW_ONE =
        "CFC";
    string public constant CF_ADAPTER_CAN_BE_USED_ONLY_ONCE = "CFD";
    string public constant CF_INCORRECT_PRICEFEED = "CFE";
    string public constant CF_TRANSFER_IS_NOT_ALLOWED = "CFF";
    string public constant CF_CREDIT_MANAGER_IS_ALREADY_SET = "CFG";

    //
    // CREDIT ACCOUNT
    //

    string public constant CA_CONNECTED_CREDIT_MANAGER_ONLY = "CA1";
    string public constant CA_FACTORY_ONLY = "CA2";

    //
    // PRICE ORACLE
    //

    string public constant PO_PRICE_FEED_DOESNT_EXIST = "PO0";
    string public constant PO_TOKENS_WITH_DECIMALS_MORE_18_ISNT_ALLOWED = "PO1";
    string public constant PO_AGGREGATOR_DECIMALS_SHOULD_BE_18 = "PO2";

    //
    // ACL
    //

    string public constant ACL_CALLER_NOT_PAUSABLE_ADMIN = "ACL1";
    string public constant ACL_CALLER_NOT_CONFIGURATOR = "ACL2";

    //
    // WETH GATEWAY
    //

    string public constant WG_DESTINATION_IS_NOT_WETH_COMPATIBLE = "WG1";
    string public constant WG_RECEIVE_IS_NOT_ALLOWED = "WG2";
    string public constant WG_NOT_ENOUGH_FUNDS = "WG3";

    //
    // LEVERAGED ACTIONS
    //

    string public constant LA_INCORRECT_VALUE = "LA1";
    string public constant LA_HAS_VALUE_WITH_TOKEN_TRANSFER = "LA2";
    string public constant LA_UNKNOWN_SWAP_INTERFACE = "LA3";
    string public constant LA_UNKNOWN_LP_INTERFACE = "LA4";
    string public constant LA_LOWER_THAN_AMOUNT_MIN = "LA5";
    string public constant LA_TOKEN_OUT_IS_NOT_COLLATERAL = "LA6";

    //
    // YEARN PRICE FEED
    //
    string public constant YPF_PRICE_PER_SHARE_OUT_OF_RANGE = "YP1";
    string public constant YPF_INCORRECT_LIMITER_PARAMETERS = "YP2";

    //
    // TOKEN DISTRIBUTOR
    //
    string public constant TD_WALLET_IS_ALREADY_CONNECTED_TO_VC = "TD1";
    string public constant TD_INCORRECT_WEIGHTS = "TD2";
    string public constant TD_NON_ZERO_BALANCE_AFTER_DISTRIBUTION = "TD3";
    string public constant TD_CONTRIBUTOR_IS_NOT_REGISTERED = "TD4";
}

// File: @openzeppelin/contracts/utils/Context.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/*
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with GSN meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address payable) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

// File: @openzeppelin/contracts/math/SafeMath.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @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, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        uint256 c = a + b;
        if (c < a) return (false, 0);
        return (true, c);
    }

    /**
     * @dev Returns the substraction of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        if (b > a) return (false, 0);
        return (true, a - b);
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryMul(uint256 a, uint256 b) internal pure returns (bool, 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 (true, 0);
        uint256 c = a * b;
        if (c / a != b) return (false, 0);
        return (true, c);
    }

    /**
     * @dev Returns the division of two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        if (b == 0) return (false, 0);
        return (true, a / b);
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        if (b == 0) return (false, 0);
        return (true, a % b);
    }

    /**
     * @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");
        return a - b;
    }

    /**
     * @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) {
        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, reverting 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) {
        require(b > 0, "SafeMath: division by zero");
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting 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;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {trySub}.
     *
     * 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);
        return a - b;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryDiv}.
     *
     * 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) {
        require(b > 0, errorMessage);
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting with custom message when dividing by zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryMod}.
     *
     * 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;
    }
}

// File: contracts/libraries/math/PercentageMath.sol



// SPDX-License-Identifier: agpl-3.0
pragma solidity ^0.7.4;

import {Errors} from "../helpers/Errors.sol";

/**
 * @title PercentageMath library
 * @author Aave
 * @notice Provides functions to perform percentage calculations
 * @dev Percentages are defined by default with 2 decimals of precision (100.00). The precision is indicated by PERCENTAGE_FACTOR
 * @dev Operations are rounded half up
 **/

library PercentageMath {
    uint256 constant PERCENTAGE_FACTOR = 1e4; //percentage plus two decimals
    uint256 constant HALF_PERCENT = PERCENTAGE_FACTOR / 2;

    /**
     * @dev Executes a percentage multiplication
     * @param value The value of which the percentage needs to be calculated
     * @param percentage The percentage of the value to be calculated
     * @return The percentage of value
     **/
    function percentMul(uint256 value, uint256 percentage)
        internal
        pure
        returns (uint256)
    {
        if (value == 0 || percentage == 0) {
            return 0; // T:[PM-1]
        }

        require(
            value <= (type(uint256).max - HALF_PERCENT) / percentage,
            Errors.MATH_MULTIPLICATION_OVERFLOW
        ); // T:[PM-1]

        return (value * percentage + HALF_PERCENT) / PERCENTAGE_FACTOR; // T:[PM-1]
    }

    /**
     * @dev Executes a percentage division
     * @param value The value of which the percentage needs to be calculated
     * @param percentage The percentage of the value to be calculated
     * @return The value divided the percentage
     **/
    function percentDiv(uint256 value, uint256 percentage)
        internal
        pure
        returns (uint256)
    {
        require(percentage != 0, Errors.MATH_DIVISION_BY_ZERO); // T:[PM-2]
        uint256 halfPercentage = percentage / 2; // T:[PM-2]

        require(
            value <= (type(uint256).max - halfPercentage) / PERCENTAGE_FACTOR,
            Errors.MATH_MULTIPLICATION_OVERFLOW
        ); // T:[PM-2]

        return (value * PERCENTAGE_FACTOR + halfPercentage) / percentage;
    }
}