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



// SPDX-License-Identifier: MIT

pragma solidity ^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/extensions/IERC20Metadata.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "../IERC20.sol";

/**
 * @dev Interface for the optional metadata functions from the ERC20 standard.
 *
 * _Available since v4.1._
 */
interface IERC20Metadata is IERC20 {
    /**
     * @dev Returns the name of the token.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the symbol of the token.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the decimals places of the token.
     */
    function decimals() external view returns (uint8);
}

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



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "../IERC20.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 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) + value;
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        unchecked {
            uint256 oldAllowance = token.allowance(address(this), spender);
            require(oldAllowance >= value, "SafeERC20: decreased allowance below zero");
            uint256 newAllowance = oldAllowance - 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. 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: @openzeppelin/contracts/utils/Address.sol



// SPDX-License-Identifier: MIT

pragma solidity ^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/utils/Context.sol



// SPDX-License-Identifier: MIT

pragma solidity ^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 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) {
        return msg.sender;
    }

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

// File: @uniswap/v2-periphery/contracts/interfaces/IUniswapV2Router01.sol



pragma solidity >=0.6.2;

interface IUniswapV2Router01 {
    function factory() external pure returns (address);
    function WETH() external pure returns (address);

    function addLiquidity(
        address tokenA,
        address tokenB,
        uint amountADesired,
        uint amountBDesired,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB, uint liquidity);
    function addLiquidityETH(
        address token,
        uint amountTokenDesired,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external payable returns (uint amountToken, uint amountETH, uint liquidity);
    function removeLiquidity(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB);
    function removeLiquidityETH(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external returns (uint amountToken, uint amountETH);
    function removeLiquidityWithPermit(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountA, uint amountB);
    function removeLiquidityETHWithPermit(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountToken, uint amountETH);
    function swapExactTokensForTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
    function swapTokensForExactTokens(
        uint amountOut,
        uint amountInMax,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
    function swapExactETHForTokens(uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);
    function swapTokensForExactETH(uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
        external
        returns (uint[] memory amounts);
    function swapExactTokensForETH(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        returns (uint[] memory amounts);
    function swapETHForExactTokens(uint amountOut, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);

    function quote(uint amountA, uint reserveA, uint reserveB) external pure returns (uint amountB);
    function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut) external pure returns (uint amountOut);
    function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut) external pure returns (uint amountIn);
    function getAmountsOut(uint amountIn, address[] calldata path) external view returns (uint[] memory amounts);
    function getAmountsIn(uint amountOut, address[] calldata path) external view returns (uint[] memory amounts);
}

// File: @uniswap/v2-periphery/contracts/interfaces/IUniswapV2Router02.sol



pragma solidity >=0.6.2;

import './IUniswapV2Router01.sol';

interface IUniswapV2Router02 is IUniswapV2Router01 {
    function removeLiquidityETHSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external returns (uint amountETH);
    function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountETH);

    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
    function swapExactETHForTokensSupportingFeeOnTransferTokens(
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external payable;
    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
}

// File: contracts/dependencies/openzeppelin/contracts/utils/structs/EnumerableSet.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Library for managing
 * https://en.wikipedia.org/wiki/Set_(abstract_data_type)[sets] of primitive
 * types.
 *
 * Sets have the following properties:
 *
 * - Elements are added, removed, and checked for existence in constant time
 * (O(1)).
 * - Elements are enumerated in O(n). No guarantees are made on the ordering.
 *
 * ```
 * contract Example {
 *     // Add the library methods
 *     using EnumerableSet for EnumerableSet.AddressSet;
 *
 *     // Declare a set state variable
 *     EnumerableSet.AddressSet private mySet;
 * }
 * ```
 *
 * As of v3.3.0, sets of type `bytes32` (`Bytes32Set`), `address` (`AddressSet`)
 * and `uint256` (`UintSet`) are supported.
 */
library EnumerableSet {
    // To implement this library for multiple types with as little code
    // repetition as possible, we write it in terms of a generic Set type with
    // bytes32 values.
    // The Set implementation uses private functions, and user-facing
    // implementations (such as AddressSet) are just wrappers around the
    // underlying Set.
    // This means that we can only create new EnumerableSets for types that fit
    // in bytes32.

    struct Set {
        // Storage of set values
        bytes32[] _values;
        // Position of the value in the `values` array, plus 1 because index 0
        // means a value is not in the set.
        mapping(bytes32 => uint256) _indexes;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function _add(Set storage set, bytes32 value) private returns (bool) {
        if (!_contains(set, value)) {
            set._values.push(value);
            // The value is stored at length-1, but we add 1 to all indexes
            // and use 0 as a sentinel value
            set._indexes[value] = set._values.length;
            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function _remove(Set storage set, bytes32 value) private returns (bool) {
        // We read and store the value's index to prevent multiple reads from the same storage slot
        uint256 valueIndex = set._indexes[value];

        if (valueIndex != 0) {
            // Equivalent to contains(set, value)
            // To delete an element from the _values array in O(1), we swap the element to delete with the last one in
            // the array, and then remove the last element (sometimes called as 'swap and pop').
            // This modifies the order of the array, as noted in {at}.

            uint256 toDeleteIndex = valueIndex - 1;
            uint256 lastIndex = set._values.length - 1;

            if (lastIndex != toDeleteIndex) {
                bytes32 lastvalue = set._values[lastIndex];

                // Move the last value to the index where the value to delete is
                set._values[toDeleteIndex] = lastvalue;
                // Update the index for the moved value
                set._indexes[lastvalue] = valueIndex; // Replace lastvalue's index to valueIndex
            }

            // Delete the slot where the moved value was stored
            set._values.pop();

            // Delete the index for the deleted slot
            delete set._indexes[value];

            return true;
        } else {
            return false;
        }
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function _contains(Set storage set, bytes32 value) private view returns (bool) {
        return set._indexes[value] != 0;
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function _length(Set storage set) private view returns (uint256) {
        return set._values.length;
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function _at(Set storage set, uint256 index) private view returns (bytes32) {
        return set._values[index];
    }

    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function _values(Set storage set) private view returns (bytes32[] memory) {
        return set._values;
    }

    // Bytes32Set

    struct Bytes32Set {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _add(set._inner, value);
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(Bytes32Set storage set, bytes32 value) internal returns (bool) {
        return _remove(set._inner, value);
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(Bytes32Set storage set, bytes32 value) internal view returns (bool) {
        return _contains(set._inner, value);
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(Bytes32Set storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(Bytes32Set storage set, uint256 index) internal view returns (bytes32) {
        return _at(set._inner, index);
    }

    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function values(Bytes32Set storage set) internal view returns (bytes32[] memory) {
        return _values(set._inner);
    }

    // AddressSet

    struct AddressSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(AddressSet storage set, address value) internal returns (bool) {
        return _add(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(AddressSet storage set, address value) internal returns (bool) {
        return _remove(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(AddressSet storage set, address value) internal view returns (bool) {
        return _contains(set._inner, bytes32(uint256(uint160(value))));
    }

    /**
     * @dev Returns the number of values in the set. O(1).
     */
    function length(AddressSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(AddressSet storage set, uint256 index) internal view returns (address) {
        return address(uint160(uint256(_at(set._inner, index))));
    }

    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function values(AddressSet storage set) internal view returns (address[] memory) {
        bytes32[] memory store = _values(set._inner);
        address[] memory result;

        assembly {
            result := store
        }

        return result;
    }

    // UintSet

    struct UintSet {
        Set _inner;
    }

    /**
     * @dev Add a value to a set. O(1).
     *
     * Returns true if the value was added to the set, that is if it was not
     * already present.
     */
    function add(UintSet storage set, uint256 value) internal returns (bool) {
        return _add(set._inner, bytes32(value));
    }

    /**
     * @dev Removes a value from a set. O(1).
     *
     * Returns true if the value was removed from the set, that is if it was
     * present.
     */
    function remove(UintSet storage set, uint256 value) internal returns (bool) {
        return _remove(set._inner, bytes32(value));
    }

    /**
     * @dev Returns true if the value is in the set. O(1).
     */
    function contains(UintSet storage set, uint256 value) internal view returns (bool) {
        return _contains(set._inner, bytes32(value));
    }

    /**
     * @dev Returns the number of values on the set. O(1).
     */
    function length(UintSet storage set) internal view returns (uint256) {
        return _length(set._inner);
    }

    /**
     * @dev Returns the value stored at position `index` in the set. O(1).
     *
     * Note that there are no guarantees on the ordering of values inside the
     * array, and it may change when more values are added or removed.
     *
     * Requirements:
     *
     * - `index` must be strictly less than {length}.
     */
    function at(UintSet storage set, uint256 index) internal view returns (uint256) {
        return uint256(_at(set._inner, index));
    }

    /**
     * @dev Return the entire set in an array
     *
     * WARNING: This operation will copy the entire storage to memory, which can be quite expensive. This is designed
     * to mostly be used by view accessors that are queried without any gas fees. Developers should keep in mind that
     * this function has an unbounded cost, and using it as part of a state-changing function may render the function
     * uncallable if the set grows to a point where copying to memory consumes too much gas to fit in a block.
     */
    function values(UintSet storage set) internal view returns (uint256[] memory) {
        bytes32[] memory store = _values(set._inner);
        uint256[] memory result;

        assembly {
            result := store
        }

        return result;
    }
}

// File: contracts/interfaces/bloq/ISwapManager.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.8.3;

/* solhint-disable func-name-mixedcase */

import "@uniswap/v2-periphery/contracts/interfaces/IUniswapV2Router02.sol";

interface ISwapManager {
    event OracleCreated(address indexed _sender, address indexed _newOracle, uint256 _period);

    function N_DEX() external view returns (uint256);

    function ROUTERS(uint256 i) external view returns (IUniswapV2Router02);

    function bestOutputFixedInput(
        address _from,
        address _to,
        uint256 _amountIn
    )
        external
        view
        returns (
            address[] memory path,
            uint256 amountOut,
            uint256 rIdx
        );

    function bestPathFixedInput(
        address _from,
        address _to,
        uint256 _amountIn,
        uint256 _i
    ) external view returns (address[] memory path, uint256 amountOut);

    function bestInputFixedOutput(
        address _from,
        address _to,
        uint256 _amountOut
    )
        external
        view
        returns (
            address[] memory path,
            uint256 amountIn,
            uint256 rIdx
        );

    function bestPathFixedOutput(
        address _from,
        address _to,
        uint256 _amountOut,
        uint256 _i
    ) external view returns (address[] memory path, uint256 amountIn);

    function safeGetAmountsOut(
        uint256 _amountIn,
        address[] memory _path,
        uint256 _i
    ) external view returns (uint256[] memory result);

    function unsafeGetAmountsOut(
        uint256 _amountIn,
        address[] memory _path,
        uint256 _i
    ) external view returns (uint256[] memory result);

    function safeGetAmountsIn(
        uint256 _amountOut,
        address[] memory _path,
        uint256 _i
    ) external view returns (uint256[] memory result);

    function unsafeGetAmountsIn(
        uint256 _amountOut,
        address[] memory _path,
        uint256 _i
    ) external view returns (uint256[] memory result);

    function comparePathsFixedInput(
        address[] memory pathA,
        address[] memory pathB,
        uint256 _amountIn,
        uint256 _i
    ) external view returns (address[] memory path, uint256 amountOut);

    function comparePathsFixedOutput(
        address[] memory pathA,
        address[] memory pathB,
        uint256 _amountOut,
        uint256 _i
    ) external view returns (address[] memory path, uint256 amountIn);

    function ours(address a) external view returns (bool);

    function oracleCount() external view returns (uint256);

    function oracleAt(uint256 idx) external view returns (address);

    function getOracle(
        address _tokenA,
        address _tokenB,
        uint256 _period,
        uint256 _i
    ) external view returns (address);

    function createOrUpdateOracle(
        address _tokenA,
        address _tokenB,
        uint256 _period,
        uint256 _i
    ) external returns (address oracleAddr);

    function consultForFree(
        address _from,
        address _to,
        uint256 _amountIn,
        uint256 _period,
        uint256 _i
    ) external view returns (uint256 amountOut, uint256 lastUpdatedAt);

    /// get the data we want and pay the gas to update
    function consult(
        address _from,
        address _to,
        uint256 _amountIn,
        uint256 _period,
        uint256 _i
    )
        external
        returns (
            uint256 amountOut,
            uint256 lastUpdatedAt,
            bool updated
        );

    function updateOracles() external returns (uint256 updated, uint256 expected);

    function updateOracles(address[] memory _oracleAddrs) external returns (uint256 updated, uint256 expected);
}

// File: contracts/interfaces/vesper/ICollateralManager.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.8.3;

interface ICollateralManager {
    function addGemJoin(address[] calldata _gemJoins) external;

    function borrow(uint256 _amount) external;

    function createVault(bytes32 _collateralType) external returns (uint256 _vaultNum);

    function depositCollateral(uint256 _amount) external;

    function payback(uint256 _amount) external;

    function transferVaultOwnership(address _newOwner) external;

    function withdrawCollateral(uint256 _amount) external;

    function getVaultBalance(address _vaultOwner) external view returns (uint256 collateralLocked);

    function getVaultDebt(address _vaultOwner) external view returns (uint256 daiDebt);

    function getVaultInfo(address _vaultOwner)
        external
        view
        returns (
            uint256 collateralLocked,
            uint256 daiDebt,
            uint256 collateralUsdRate,
            uint256 collateralRatio,
            uint256 minimumDebt
        );

    function mcdManager() external view returns (address);

    function vaultNum(address _vaultOwner) external view returns (uint256 _vaultNum);

    function whatWouldWithdrawDo(address _vaultOwner, uint256 _amount)
        external
        view
        returns (
            uint256 collateralLocked,
            uint256 daiDebt,
            uint256 collateralUsdRate,
            uint256 collateralRatio,
            uint256 minimumDebt
        );
}

// File: contracts/interfaces/vesper/IPoolRewards.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.8.3;

interface IPoolRewards {
    /// Emitted after reward added
    event RewardAdded(address indexed rewardToken, uint256 reward, uint256 rewardDuration);
    /// Emitted whenever any user claim rewards
    event RewardPaid(address indexed user, address indexed rewardToken, uint256 reward);
    /// Emitted after adding new rewards token into rewardTokens array
    event RewardTokenAdded(address indexed rewardToken, address[] existingRewardTokens);

    function claimReward(address) external;

    function notifyRewardAmount(
        address _rewardToken,
        uint256 _rewardAmount,
        uint256 _rewardDuration
    ) external;

    function notifyRewardAmount(
        address[] memory _rewardTokens,
        uint256[] memory _rewardAmounts,
        uint256[] memory _rewardDurations
    ) external;

    function updateReward(address) external;

    function claimable(address _account)
        external
        view
        returns (address[] memory _rewardTokens, uint256[] memory _claimableAmounts);

    function lastTimeRewardApplicable(address _rewardToken) external view returns (uint256);

    function rewardForDuration()
        external
        view
        returns (address[] memory _rewardTokens, uint256[] memory _rewardForDuration);

    function rewardPerToken()
        external
        view
        returns (address[] memory _rewardTokens, uint256[] memory _rewardPerTokenRate);
}

// File: contracts/interfaces/vesper/IStrategy.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.8.3;

interface IStrategy {
    function rebalance() external;

    function sweepERC20(address _fromToken) external;

    function withdraw(uint256 _amount) external;

    function feeCollector() external view returns (address);

    function isReservedToken(address _token) external view returns (bool);

    function keepers() external view returns (address[] memory);

    function migrate(address _newStrategy) external;

    function token() external view returns (address);

    function totalValue() external view returns (uint256);

    function totalValueCurrent() external returns (uint256);

    function pool() external view returns (address);
}

// File: contracts/interfaces/vesper/IVesperPool.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.8.3;
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";

interface IVesperPool is IERC20 {
    function deposit() external payable;

    function deposit(uint256 _share) external;

    function multiTransfer(address[] memory _recipients, uint256[] memory _amounts) external returns (bool);

    function excessDebt(address _strategy) external view returns (uint256);

    function permit(
        address,
        address,
        uint256,
        uint256,
        uint8,
        bytes32,
        bytes32
    ) external;

    function poolRewards() external returns (address);

    function reportEarning(
        uint256 _profit,
        uint256 _loss,
        uint256 _payback
    ) external;

    function reportLoss(uint256 _loss) external;

    function resetApproval() external;

    function sweepERC20(address _fromToken) external;

    function withdraw(uint256 _amount) external;

    function withdrawETH(uint256 _amount) external;

    function whitelistedWithdraw(uint256 _amount) external;

    function governor() external view returns (address);

    function keepers() external view returns (address[] memory);

    function isKeeper(address _address) external view returns (bool);

    function maintainers() external view returns (address[] memory);

    function isMaintainer(address _address) external view returns (bool);

    function feeCollector() external view returns (address);

    function pricePerShare() external view returns (uint256);

    function strategy(address _strategy)
        external
        view
        returns (
            bool _active,
            uint256 _interestFee,
            uint256 _debtRate,
            uint256 _lastRebalance,
            uint256 _totalDebt,
            uint256 _totalLoss,
            uint256 _totalProfit,
            uint256 _debtRatio
        );

    function stopEverything() external view returns (bool);

    function token() external view returns (IERC20);

    function tokensHere() external view returns (uint256);

    function totalDebtOf(address _strategy) external view returns (uint256);

    function totalValue() external view returns (uint256);

    function withdrawFee() external view returns (uint256);

    // Function to get pricePerShare from V2 pools
    function getPricePerShare() external view returns (uint256);
}

// File: contracts/strategies/Strategy.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.8.3;

import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "@openzeppelin/contracts/utils/Context.sol";
import "../dependencies/openzeppelin/contracts/utils/structs/EnumerableSet.sol";
import "../interfaces/bloq/ISwapManager.sol";
import "../interfaces/vesper/IStrategy.sol";
import "../interfaces/vesper/IVesperPool.sol";

abstract contract Strategy is IStrategy, Context {
    using SafeERC20 for IERC20;
    using EnumerableSet for EnumerableSet.AddressSet;

    address internal constant ETH = 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE;
    uint256 internal constant MAX_UINT_VALUE = type(uint256).max;

    // solhint-disable-next-line  var-name-mixedcase
    address internal WETH = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;
    IERC20 public immutable collateralToken;
    address public receiptToken;
    address public immutable override pool;
    address public override feeCollector;
    ISwapManager public swapManager;

    uint256 public oraclePeriod = 3600; // 1h
    uint256 public oracleRouterIdx = 0; // Uniswap V2
    uint256 public swapSlippage = 10000; // 100% Don't use oracles by default

    EnumerableSet.AddressSet private _keepers;

    event UpdatedFeeCollector(address indexed previousFeeCollector, address indexed newFeeCollector);
    event UpdatedSwapManager(address indexed previousSwapManager, address indexed newSwapManager);
    event UpdatedSwapSlippage(uint256 oldSwapSlippage, uint256 newSwapSlippage);
    event UpdatedOracleConfig(uint256 oldPeriod, uint256 newPeriod, uint256 oldRouterIdx, uint256 newRouterIdx);

    constructor(
        address _pool,
        address _swapManager,
        address _receiptToken
    ) {
        require(_pool != address(0), "pool-address-is-zero");
        require(_swapManager != address(0), "sm-address-is-zero");
        swapManager = ISwapManager(_swapManager);
        pool = _pool;
        collateralToken = IVesperPool(_pool).token();
        receiptToken = _receiptToken;
        require(_keepers.add(_msgSender()), "add-keeper-failed");
    }

    modifier onlyGovernor {
        require(_msgSender() == IVesperPool(pool).governor(), "caller-is-not-the-governor");
        _;
    }

    modifier onlyKeeper() {
        require(_keepers.contains(_msgSender()), "caller-is-not-a-keeper");
        _;
    }

    modifier onlyPool() {
        require(_msgSender() == pool, "caller-is-not-vesper-pool");
        _;
    }

    /**
     * @notice Add given address in keepers list.
     * @param _keeperAddress keeper address to add.
     */
    function addKeeper(address _keeperAddress) external onlyGovernor {
        require(_keepers.add(_keeperAddress), "add-keeper-failed");
    }

    /// @notice Return list of keepers
    function keepers() external view override returns (address[] memory) {
        return _keepers.values();
    }

    /**
     * @notice Migrate all asset and vault ownership,if any, to new strategy
     * @dev _beforeMigration hook can be implemented in child strategy to do extra steps.
     * @param _newStrategy Address of new strategy
     */
    function migrate(address _newStrategy) external virtual override onlyPool {
        require(_newStrategy != address(0), "new-strategy-address-is-zero");
        require(IStrategy(_newStrategy).pool() == pool, "not-valid-new-strategy");
        _beforeMigration(_newStrategy);
        IERC20(receiptToken).safeTransfer(_newStrategy, IERC20(receiptToken).balanceOf(address(this)));
        collateralToken.safeTransfer(_newStrategy, collateralToken.balanceOf(address(this)));
    }

    /**
     * @notice Remove given address from keepers list.
     * @param _keeperAddress keeper address to remove.
     */
    function removeKeeper(address _keeperAddress) external onlyGovernor {
        require(_keepers.remove(_keeperAddress), "remove-keeper-failed");
    }

    /**
     * @notice Update fee collector
     * @param _feeCollector fee collector address
     */
    function updateFeeCollector(address _feeCollector) external onlyGovernor {
        require(_feeCollector != address(0), "fee-collector-address-is-zero");
        require(_feeCollector != feeCollector, "fee-collector-is-same");
        emit UpdatedFeeCollector(feeCollector, _feeCollector);
        feeCollector = _feeCollector;
    }

    /**
     * @notice Update swap manager address
     * @param _swapManager swap manager address
     */
    function updateSwapManager(address _swapManager) external onlyGovernor {
        require(_swapManager != address(0), "sm-address-is-zero");
        require(_swapManager != address(swapManager), "sm-is-same");
        emit UpdatedSwapManager(address(swapManager), _swapManager);
        swapManager = ISwapManager(_swapManager);
    }

    function updateSwapSlippage(uint256 _newSwapSlippage) external onlyGovernor {
        require(_newSwapSlippage <= 10000, "invalid-slippage-value");
        emit UpdatedSwapSlippage(swapSlippage, _newSwapSlippage);
        swapSlippage = _newSwapSlippage;
    }

    function updateOracleConfig(uint256 _newPeriod, uint256 _newRouterIdx) external onlyGovernor {
        require(_newRouterIdx < swapManager.N_DEX(), "invalid-router-index");
        if (_newPeriod == 0) _newPeriod = oraclePeriod;
        require(_newPeriod > 59, "invalid-oracle-period");
        emit UpdatedOracleConfig(oraclePeriod, _newPeriod, oracleRouterIdx, _newRouterIdx);
        oraclePeriod = _newPeriod;
        oracleRouterIdx = _newRouterIdx;
    }

    /// @dev Approve all required tokens
    function approveToken() external onlyKeeper {
        _approveToken(0);
        _approveToken(MAX_UINT_VALUE);
    }

    function setupOracles() external onlyKeeper {
        _setupOracles();
    }

    /**
     * @dev Withdraw collateral token from lending pool.
     * @param _amount Amount of collateral token
     */
    function withdraw(uint256 _amount) external override onlyPool {
        _withdraw(_amount);
    }

    /**
     * @dev Rebalance profit, loss and investment of this strategy
     */
    function rebalance() external virtual override onlyKeeper {
        (uint256 _profit, uint256 _loss, uint256 _payback) = _generateReport();
        IVesperPool(pool).reportEarning(_profit, _loss, _payback);
        _reinvest();
    }

    /**
     * @dev sweep given token to feeCollector of strategy
     * @param _fromToken token address to sweep
     */
    function sweepERC20(address _fromToken) external override onlyKeeper {
        require(feeCollector != address(0), "fee-collector-not-set");
        require(_fromToken != address(collateralToken), "not-allowed-to-sweep-collateral");
        require(!isReservedToken(_fromToken), "not-allowed-to-sweep");
        if (_fromToken == ETH) {
            Address.sendValue(payable(feeCollector), address(this).balance);
        } else {
            uint256 _amount = IERC20(_fromToken).balanceOf(address(this));
            IERC20(_fromToken).safeTransfer(feeCollector, _amount);
        }
    }

    /// @notice Returns address of token correspond to collateral token
    function token() external view override returns (address) {
        return receiptToken;
    }

    /**
     * @notice Calculate total value of asset under management
     * @dev Report total value in collateral token
     */
    function totalValue() public view virtual override returns (uint256 _value);

    /**
     * @notice Calculate total value of asset under management (in real-time)
     * @dev Report total value in collateral token
     */
    function totalValueCurrent() external virtual override returns (uint256) {
        return totalValue();
    }

    /// @notice Check whether given token is reserved or not. Reserved tokens are not allowed to sweep.
    function isReservedToken(address _token) public view virtual override returns (bool);

    /**
     * @notice some strategy may want to prepare before doing migration.
        Example In Maker old strategy want to give vault ownership to new strategy
     * @param _newStrategy .
     */
    function _beforeMigration(address _newStrategy) internal virtual;

    /**
     *  @notice Generate report for current profit and loss. Also liquidate asset to payback
     * excess debt, if any.
     * @return _profit Calculate any realized profit and convert it to collateral, if not already.
     * @return _loss Calculate any loss that strategy has made on investment. Convert into collateral token.
     * @return _payback If strategy has any excess debt, we have to liquidate asset to payback excess debt.
     */
    function _generateReport()
        internal
        virtual
        returns (
            uint256 _profit,
            uint256 _loss,
            uint256 _payback
        )
    {
        uint256 _excessDebt = IVesperPool(pool).excessDebt(address(this));
        uint256 _totalDebt = IVesperPool(pool).totalDebtOf(address(this));
        _profit = _realizeProfit(_totalDebt);
        _loss = _realizeLoss(_totalDebt);
        _payback = _liquidate(_excessDebt);
    }

    function _calcAmtOutAfterSlippage(uint256 _amount, uint256 _slippage) internal pure returns (uint256) {
        return (_amount * (10000 - _slippage)) / (10000);
    }

    function _simpleOraclePath(address _from, address _to) internal view returns (address[] memory path) {
        if (_from == WETH || _to == WETH) {
            path = new address[](2);
            path[0] = _from;
            path[1] = _to;
        } else {
            path = new address[](3);
            path[0] = _from;
            path[1] = WETH;
            path[2] = _to;
        }
    }

    function _consultOracle(
        address _from,
        address _to,
        uint256 _amt
    ) internal returns (uint256, bool) {
        for (uint256 i = 0; i < swapManager.N_DEX(); i++) {
            (bool _success, bytes memory _returnData) =
                address(swapManager).call(
                    abi.encodePacked(swapManager.consult.selector, abi.encode(_from, _to, _amt, oraclePeriod, i))
                );
            if (_success) {
                (uint256 rate, uint256 lastUpdate, ) = abi.decode(_returnData, (uint256, uint256, bool));
                if ((lastUpdate > (block.timestamp - oraclePeriod)) && (rate != 0)) return (rate, true);
                return (0, false);
            }
        }
        return (0, false);
    }

    function _getOracleRate(address[] memory path, uint256 _amountIn) internal returns (uint256 amountOut) {
        require(path.length > 1, "invalid-oracle-path");
        amountOut = _amountIn;
        bool isValid;
        for (uint256 i = 0; i < path.length - 1; i++) {
            (amountOut, isValid) = _consultOracle(path[i], path[i + 1], amountOut);
            require(isValid, "invalid-oracle-rate");
        }
    }

    /**
     * @notice Safe swap via Uniswap / Sushiswap (better rate of the two)
     * @dev There are many scenarios when token swap via Uniswap can fail, so this
     * method will wrap Uniswap call in a 'try catch' to make it fail safe.
     * however, this method will throw minAmountOut is not met
     * @param _from address of from token
     * @param _to address of to token
     * @param _amountIn Amount to be swapped
     * @param _minAmountOut minimum amount out
     */
    function _safeSwap(
        address _from,
        address _to,
        uint256 _amountIn,
        uint256 _minAmountOut
    ) internal {
        (address[] memory path, uint256 amountOut, uint256 rIdx) =
            swapManager.bestOutputFixedInput(_from, _to, _amountIn);
        if (_minAmountOut == 0) _minAmountOut = 1;
        if (amountOut != 0) {
            swapManager.ROUTERS(rIdx).swapExactTokensForTokens(
                _amountIn,
                _minAmountOut,
                path,
                address(this),
                block.timestamp
            );
        }
    }

    // These methods can be implemented by the inheriting strategy.
    /* solhint-disable no-empty-blocks */
    function _claimRewardsAndConvertTo(address _toToken) internal virtual {}

    /**
     * @notice Set up any oracles that are needed for this strategy.
     */
    function _setupOracles() internal virtual {}

    /* solhint-enable */

    // These methods must be implemented by the inheriting strategy
    function _withdraw(uint256 _amount) internal virtual;

    function _approveToken(uint256 _amount) internal virtual;

    /**
     * @notice Withdraw collateral to payback excess debt in pool.
     * @param _excessDebt Excess debt of strategy in collateral token
     * @return _payback amount in collateral token. Usually it is equal to excess debt.
     */
    function _liquidate(uint256 _excessDebt) internal virtual returns (uint256 _payback);

    /**
     * @notice Calculate earning and withdraw/convert it into collateral token.
     * @param _totalDebt Total collateral debt of this strategy
     * @return _profit Profit in collateral token
     */
    function _realizeProfit(uint256 _totalDebt) internal virtual returns (uint256 _profit);

    /**
     * @notice Calculate loss
     * @param _totalDebt Total collateral debt of this strategy
     * @return _loss Realized loss in collateral token
     */
    function _realizeLoss(uint256 _totalDebt) internal virtual returns (uint256 _loss);

    /**
     * @notice Reinvest collateral.
     * @dev Once we file report back in pool, we might have some collateral in hand
     * which we want to reinvest aka deposit in lender/provider.
     */
    function _reinvest() internal virtual;
}

// File: contracts/strategies/maker/MakerStrategy.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.8.3;

import "@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol";
import "../Strategy.sol";
import "../../interfaces/vesper/ICollateralManager.sol";

/// @dev This strategy will deposit collateral token in Maker, borrow Dai and
/// deposit borrowed DAI in other lending pool to earn interest.
abstract contract MakerStrategy is Strategy {
    using SafeERC20 for IERC20;

    // solhint-disable-next-line var-name-mixedcase
    string public NAME;
    string public constant VERSION = "4.0.0";

    address internal constant DAI = 0x6B175474E89094C44Da98b954EedeAC495271d0F;
    ICollateralManager public immutable cm;
    bytes32 public immutable collateralType;
    uint256 public highWater;
    uint256 public lowWater;
    uint256 public decimalConversionFactor;
    uint256 private constant WAT = 10**16;

    constructor(
        address _pool,
        address _cm,
        address _swapManager,
        address _receiptToken,
        bytes32 _collateralType,
        string memory _name
    ) Strategy(_pool, _swapManager, _receiptToken) {
        require(_cm != address(0), "cm-address-is-zero");
        collateralType = _collateralType;
        cm = ICollateralManager(_cm);
        // Assuming token supports 18 or less decimals.
        uint256 _decimals = IERC20Metadata(address(IVesperPool(_pool).token())).decimals();
        decimalConversionFactor = 10**(18 - _decimals);
        NAME = _name;
    }

    /// @notice Create new Maker vault
    function createVault() external onlyGovernor {
        cm.createVault(collateralType);
    }

    /**
     * @dev If pool is underwater this function will resolve underwater condition.
     * If Debt in Maker is greater than Dai balance in lender then pool is underwater.
     * Lowering DAI debt in Maker will resolve underwater condition.
     * Resolve: Calculate required collateral token to lower DAI debt. Withdraw required
     * collateral token from Maker and convert those to DAI via Uniswap.
     * Finally payback debt in Maker using DAI.
     * @dev Also report loss in pool.
     */
    function resurface() external onlyKeeper {
        _resurface();
    }

    /**
     * @notice Update balancing factors aka high water and low water values.
     * Water mark values represent Collateral Ratio in Maker. For example 300 as high water
     * means 300% collateral ratio.
     * @param _highWater Value for high water mark.
     * @param _lowWater Value for low water mark.
     */
    function updateBalancingFactor(uint256 _highWater, uint256 _lowWater) external onlyGovernor {
        require(_lowWater != 0, "lowWater-is-zero");
        require(_highWater > _lowWater, "highWater-less-than-lowWater");
        highWater = _highWater * WAT;
        lowWater = _lowWater * WAT;
    }

    /// @dev Convert from 18 decimals to token defined decimals.
    function convertFrom18(uint256 _amount) public view returns (uint256) {
        return _amount / decimalConversionFactor;
    }

    /**
     * @notice Report total value of this strategy
     * @dev Make sure to return value in collateral token and in order to do that
     * we are using Uniswap to get collateral amount for earned DAI.
     */
    function totalValue() public view virtual override returns (uint256 _totalValue) {
        uint256 _daiBalance = _getDaiBalance();
        uint256 _debt = cm.getVaultDebt(address(this));
        if (_daiBalance > _debt) {
            uint256 _daiEarned = _daiBalance - _debt;
            (, _totalValue) = swapManager.bestPathFixedInput(DAI, address(collateralToken), _daiEarned, 0);
        }
        _totalValue += convertFrom18(cm.getVaultBalance(address(this)));
    }

    function vaultNum() external view returns (uint256) {
        return cm.vaultNum(address(this));
    }

    /// @dev Check whether given token is reserved or not. Reserved tokens are not allowed to sweep.
    function isReservedToken(address _token) public view virtual override returns (bool) {
        return _token == receiptToken;
    }

    /**
     * @notice Returns true if pool is underwater.
     * @notice Underwater - If debt is greater than (earning of pool + DAI in pool + some wei buffer).
     * @notice Earning - Sum of DAI balance and DAI from accrued reward, if any, in lending pool.
     */
    function isUnderwater() public view virtual returns (bool) {
        return cm.getVaultDebt(address(this)) > (_getDaiBalance() + IERC20(DAI).balanceOf(address(this)) + 1_000);
    }

    /**
     * @notice Before migration hook. It will be called during migration
     * @dev Transfer Maker vault ownership to new strategy
     * @param _newStrategy Address of new strategy.
     */
    function _beforeMigration(address _newStrategy) internal virtual override {
        require(MakerStrategy(_newStrategy).collateralType() == collateralType, "collateral-type-must-be-the-same");
        cm.transferVaultOwnership(_newStrategy);
    }

    function _approveToken(uint256 _amount) internal virtual override {
        IERC20(DAI).safeApprove(address(cm), _amount);
        collateralToken.safeApprove(address(cm), _amount);
        collateralToken.safeApprove(pool, _amount);
        for (uint256 i = 0; i < swapManager.N_DEX(); i++) {
            collateralToken.safeApprove(address(swapManager.ROUTERS(i)), _amount);
            IERC20(DAI).safeApprove(address(swapManager.ROUTERS(i)), _amount);
        }
    }

    function _moveDaiToMaker(uint256 _amount) internal {
        if (_amount != 0) {
            _withdrawDaiFromLender(_amount);
            cm.payback(_amount);
        }
    }

    function _moveDaiFromMaker(uint256 _amount) internal virtual {
        cm.borrow(_amount);
        _amount = IERC20(DAI).balanceOf(address(this));
        _depositDaiToLender(_amount);
    }

    /**
     * @notice Withdraw collateral to payback excess debt in pool.
     * @param _excessDebt Excess debt of strategy in collateral token
     * @return payback amount in collateral token. Usually it is equal to excess debt.
     */
    function _liquidate(uint256 _excessDebt) internal virtual override returns (uint256) {
        _withdrawHere(_excessDebt);
        return _excessDebt;
    }

    /**
     * @notice Calculate earning and convert it to collateral token
     * @dev Also claim rewards if available.
     *      Withdraw excess DAI from lender.
     *      Swap net earned DAI to collateral token
     * @return profit in collateral token
     */
    function _realizeProfit(
        uint256 /*_totalDebt*/
    ) internal virtual override returns (uint256) {
        _claimRewardsAndConvertTo(DAI);
        _rebalanceDaiInLender();
        uint256 _daiBalance = IERC20(DAI).balanceOf(address(this));
        if (_daiBalance != 0) {
            _safeSwap(DAI, address(collateralToken), _daiBalance, 1);
        }
        return collateralToken.balanceOf(address(this));
    }

    /**
     * @notice Calculate collateral loss from resurface, if any
     * @dev Difference of total debt of strategy in pool and collateral locked
     *      in Maker vault is the loss.
     * @return loss in collateral token
     */
    function _realizeLoss(uint256 _totalDebt) internal virtual override returns (uint256) {
        uint256 _collateralLocked = convertFrom18(cm.getVaultBalance(address(this)));
        return _totalDebt > _collateralLocked ? _totalDebt - _collateralLocked : 0;
    }

    /**
     * @notice Deposit collateral in Maker and rebalance collateral and debt in Maker.
     * @dev Based on defined risk parameter either borrow more DAI from Maker or
     * payback some DAI in Maker. It will try to mitigate risk of liquidation.
     */
    function _reinvest() internal virtual override {
        uint256 _collateralBalance = collateralToken.balanceOf(address(this));
        if (_collateralBalance != 0) {
            cm.depositCollateral(_collateralBalance);
        }

        (
            uint256 _collateralLocked,
            uint256 _currentDebt,
            uint256 _collateralUsdRate,
            uint256 _collateralRatio,
            uint256 _minimumAllowedDebt
        ) = cm.getVaultInfo(address(this));
        uint256 _maxDebt = (_collateralLocked * _collateralUsdRate) / highWater;
        if (_maxDebt < _minimumAllowedDebt) {
            // Dusting Scenario:: Based on collateral locked, if our max debt is less
            // than Maker defined minimum debt then payback whole debt and wind up.
            _moveDaiToMaker(_currentDebt);
        } else {
            if (_collateralRatio > highWater) {
                require(!isUnderwater(), "pool-is-underwater");
                // Safe to borrow more DAI
                _moveDaiFromMaker(_maxDebt - _currentDebt);
            } else if (_collateralRatio < lowWater) {
                // Being below low water brings risk of liquidation in Maker.
                // Withdraw DAI from Lender and deposit in Maker
                _moveDaiToMaker(_currentDebt - _maxDebt);
            }
        }
    }

    function _resurface() internal virtual {
        require(isUnderwater(), "pool-is-above-water");
        uint256 _daiNeeded = cm.getVaultDebt(address(this)) - _getDaiBalance();
        (address[] memory _path, uint256 _collateralNeeded, uint256 rIdx) =
            swapManager.bestInputFixedOutput(address(collateralToken), DAI, _daiNeeded);
        if (_collateralNeeded != 0) {
            cm.withdrawCollateral(_collateralNeeded);
            swapManager.ROUTERS(rIdx).swapExactTokensForTokens(
                _collateralNeeded,
                1,
                _path,
                address(this),
                block.timestamp
            );
            cm.payback(IERC20(DAI).balanceOf(address(this)));
            IVesperPool(pool).reportLoss(_collateralNeeded);
        }
    }

    function _withdraw(uint256 _amount) internal override {
        _withdrawHere(_amount);
        collateralToken.safeTransfer(pool, collateralToken.balanceOf(address(this)));
    }

    // TODO do we need a safe withdraw
    function _withdrawHere(uint256 _amount) internal {
        (
            uint256 collateralLocked,
            uint256 debt,
            uint256 collateralUsdRate,
            uint256 collateralRatio,
            uint256 minimumDebt
        ) = cm.whatWouldWithdrawDo(address(this), _amount);
        if (debt != 0 && collateralRatio < lowWater) {
            // If this withdraw results in Low Water scenario.
            uint256 maxDebt = (collateralLocked * collateralUsdRate) / highWater;
            if (maxDebt < minimumDebt) {
                // This is Dusting scenario
                _moveDaiToMaker(debt);
            } else if (maxDebt < debt) {
                _moveDaiToMaker(debt - maxDebt);
            }
        }
        cm.withdrawCollateral(_amount);
    }

    function _depositDaiToLender(uint256 _amount) internal virtual;

    function _rebalanceDaiInLender() internal virtual;

    function _withdrawDaiFromLender(uint256 _amount) internal virtual;

    function _getDaiBalance() internal view virtual returns (uint256);
}

// File: contracts/strategies/maker/VesperMakerStrategy.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.8.3;

import "./MakerStrategy.sol";
import "../../interfaces/vesper/IPoolRewards.sol";

/// @dev This strategy will deposit collateral token in Maker, borrow Dai and
/// deposit borrowed DAI in Vesper DAI pool to earn interest.
contract VesperMakerStrategy is MakerStrategy {
    using SafeERC20 for IERC20;
    address internal constant VSP = 0x1b40183EFB4Dd766f11bDa7A7c3AD8982e998421;

    constructor(
        address _pool,
        address _cm,
        address _swapManager,
        address _vPool,
        bytes32 _collateralType,
        string memory _name
    ) MakerStrategy(_pool, _cm, _swapManager, _vPool, _collateralType, _name) {
        require(address(IVesperPool(_vPool).token()) == DAI, "not-a-valid-dai-pool");
    }

    function _approveToken(uint256 _amount) internal override {
        super._approveToken(_amount);
        IERC20(DAI).safeApprove(address(receiptToken), _amount);
        for (uint256 i = 0; i < swapManager.N_DEX(); i++) {
            IERC20(VSP).safeApprove(address(swapManager.ROUTERS(i)), _amount);
        }
    }

    function _getDaiBalance() internal view override returns (uint256) {
        return (IVesperPool(receiptToken).pricePerShare() * IVesperPool(receiptToken).balanceOf(address(this))) / 1e18;
    }

    function _depositDaiToLender(uint256 _amount) internal override {
        IVesperPool(receiptToken).deposit(_amount);
    }

    function _withdrawDaiFromLender(uint256 _amount) internal override {
        uint256 _pricePerShare = IVesperPool(receiptToken).pricePerShare();
        uint256 _share = (_amount * 1e18) / _pricePerShare;
        // Should not withdraw less than requested amount
        _share = _amount > ((_share * _pricePerShare) / 1e18) ? _share + 1 : _share;
        IVesperPool(receiptToken).whitelistedWithdraw(_share);
    }

    function _rebalanceDaiInLender() internal virtual override {
        uint256 _daiDebt = cm.getVaultDebt(address(this));
        uint256 _daiBalance = _getDaiBalance();
        if (_daiBalance > _daiDebt) {
            _withdrawDaiFromLender(_daiBalance - _daiDebt);
        }
    }

    /// @notice Claim rewardToken from lender and convert it into DAI
    function _claimRewardsAndConvertTo(address _toToken) internal virtual override {
        uint256 _vspAmount = IERC20(VSP).balanceOf(address(this));
        if (_vspAmount > 0) {
            _safeSwap(VSP, _toToken, _vspAmount, 1);
        }
    }
}