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



// SPDX-License-Identifier: MIT

pragma solidity 0.8.9;

interface IStrategy {
    function rebalance()
        external
        returns (
            uint256 _profit,
            uint256 _loss,
            uint256 _payback
        );

    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 pool() external view returns (address);

    // solhint-disable-next-line func-name-mixedcase
    function VERSION() external view returns (string memory);

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

// File: vesper-pools/contracts/dependencies/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: vesper-pools/contracts/dependencies/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: vesper-pools/contracts/dependencies/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: vesper-pools/contracts/dependencies/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: vesper-pools/contracts/dependencies/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: vesper-pools/contracts/dependencies/openzeppelin/contracts/utils/math/Math.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Standard math utilities missing in the Solidity language.
 */
library Math {
    /**
     * @dev Returns the largest of two numbers.
     */
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a >= b ? a : b;
    }

    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }

    /**
     * @dev Returns the average of two numbers. The result is rounded towards
     * zero.
     */
    function average(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b) / 2 can overflow, so we distribute
        return (a / 2) + (b / 2) + ((a % 2 + b % 2) / 2);
    }
}

// File: vesper-pools/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: vesper-pools/contracts/interfaces/token/IToken.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.8.9;

import "../../dependencies/openzeppelin/contracts/token/ERC20/IERC20.sol";

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

    function withdraw(uint256) external;
}

// File: vesper-pools/contracts/interfaces/vesper/IGovernable.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.8.9;

/**
 * @notice Governable interface
 */
interface IGovernable {
    function governor() external view returns (address _governor);

    function transferGovernorship(address _proposedGovernor) external;
}

// File: vesper-pools/contracts/interfaces/vesper/IPausable.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.8.9;

/**
 * @notice Pausable interface
 */
interface IPausable {
    function paused() external view returns (bool);

    function stopEverything() external view returns (bool);

    function pause() external;

    function unpause() external;

    function shutdown() external;

    function open() external;
}

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



// SPDX-License-Identifier: MIT

pragma solidity 0.8.9;

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: vesper-pools/contracts/interfaces/vesper/IVesperPool.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.8.9;

import "../../dependencies/openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol";
import "./IGovernable.sol";
import "./IPausable.sol";

interface IVesperPool is IGovernable, IPausable, IERC20Metadata {
    function calculateUniversalFee(uint256 _profit) external view returns (uint256 _fee);

    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 poolAccountant() external view returns (address);

    function poolRewards() external view returns (address);

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

    function reportLoss(uint256 _loss) external;

    function sweepERC20(address _fromToken) external;

    function withdraw(uint256 _amount) external;

    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 pricePerShare() external view returns (uint256);

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

    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 totalDebt() external view returns (uint256);
}

// File: vesper-strategies/contracts/interfaces/compound/ICompound.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.8.9;

interface CToken {
    function accrueInterest() external returns (uint256);

    function balanceOf(address owner) external view returns (uint256);

    function balanceOfUnderlying(address owner) external returns (uint256);

    function borrowBalanceCurrent(address account) external returns (uint256);

    function borrowBalanceStored(address account) external view returns (uint256);

    function exchangeRateCurrent() external returns (uint256);

    function exchangeRateStored() external view returns (uint256);

    function getAccountSnapshot(address account)
        external
        view
        returns (
            uint256,
            uint256,
            uint256,
            uint256
        );

    function borrow(uint256 borrowAmount) external returns (uint256);

    function mint() external payable; // For ETH

    function mint(uint256 mintAmount) external returns (uint256); // For ERC20

    function redeem(uint256 redeemTokens) external returns (uint256);

    function redeemUnderlying(uint256 redeemAmount) external returns (uint256);

    function repayBorrow() external payable; // For ETH

    function repayBorrow(uint256 repayAmount) external returns (uint256); // For ERC20

    function transfer(address user, uint256 amount) external returns (bool);

    function getCash() external view returns (uint256);

    function transferFrom(
        address owner,
        address user,
        uint256 amount
    ) external returns (bool);

    function underlying() external view returns (address);

    function comptroller() external view returns (address);

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

interface Comptroller {
    function claimComp(address holder, address[] memory) external;

    function enterMarkets(address[] memory cTokens) external returns (uint256[] memory);

    function exitMarket(address cToken) external returns (uint256);

    function compAccrued(address holder) external view returns (uint256);

    function getAccountLiquidity(address account)
        external
        view
        returns (
            uint256,
            uint256,
            uint256
        );

    function markets(address market)
        external
        view
        returns (
            bool isListed,
            uint256 collateralFactorMantissa,
            bool isCompted
        );

    function oracle() external view returns (address);

    function borrowCaps(address market) external view returns (uint256);

    function compSupplySpeeds(address cToken) external view returns (uint256);
}

interface VenusComptroller is Comptroller {
    function claimVenus(address holder, address[] memory) external;
}

interface Oracle {
    function getUnderlyingPrice(address cToken) external view returns (uint256);

    function price(string memory symbol) external view returns (uint256);
}

// File: vesper-strategies/contracts/interfaces/swapper/IRoutedSwapper.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.8.9;

/**
 * @notice Routed Swapper interface
 * @dev This contract doesn't support native coins (e.g. ETH, AVAX, MATIC, etc) use wrapper tokens instead
 */
interface IRoutedSwapper {
    /**
     * @notice The list of supported DEXes
     * @dev This function is gas intensive
     */
    function getAllExchanges() external view returns (address[] memory);

    /**
     * @notice Get *spot* quote
     * It will return the swap amount based on the current reserves of the best pair/path found (i.e. spot price).
     * @dev It shouldn't be used as oracle!!!
     */
    function getAmountIn(
        address tokenIn_,
        address tokenOut_,
        uint256 amountOut_
    ) external returns (uint256 _amountIn);

    /**
     * @notice Get *spot* quote
     * It will return the swap amount based on the current reserves of the best pair/path found (i.e. spot price).
     * @dev It shouldn't be used as oracle!!!
     */
    function getAmountOut(
        address tokenIn_,
        address tokenOut_,
        uint256 amountIn_
    ) external returns (uint256 _amountOut);

    /**
     * @notice Perform an exact input swap - will revert if there is no default routing
     */
    function swapExactInput(
        address tokenIn_,
        address tokenOut_,
        uint256 amountIn_,
        uint256 amountOutMin_,
        address _receiver
    ) external returns (uint256 _amountOut);

    /**
     * @notice Perform an exact output swap - will revert if there is no default routing
     */
    function swapExactOutput(
        address tokenIn_,
        address tokenOut_,
        uint256 amountOut_,
        uint256 amountInMax_,
        address receiver_
    ) external returns (uint256 _amountIn);
}

// File: vesper-strategies/contracts/strategies/Strategy.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.8.9;

import "vesper-pools/contracts/interfaces/vesper/IVesperPool.sol";
import "vesper-pools/contracts/dependencies/openzeppelin/contracts/token/ERC20/IERC20.sol";
import "vesper-pools/contracts/dependencies/openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "vesper-pools/contracts/dependencies/openzeppelin/contracts/utils/Context.sol";
import "vesper-pools/contracts/dependencies/openzeppelin/contracts/utils/structs/EnumerableSet.sol";
import "vesper-pools/contracts/dependencies/openzeppelin/contracts/utils/math/Math.sol";
import "vesper-commons/contracts/interfaces/vesper/IStrategy.sol";
import "../interfaces/swapper/IRoutedSwapper.sol";

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

    IERC20 public immutable collateralToken;
    address public receiptToken;
    address public immutable override pool;
    address public override feeCollector;
    IRoutedSwapper public swapper;
    address internal constant ETH = 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE;
    uint256 internal constant MAX_UINT_VALUE = type(uint256).max;

    EnumerableSet.AddressSet private _keepers;

    event UpdatedFeeCollector(address indexed previousFeeCollector, address indexed newFeeCollector);
    event UpdatedSwapper(IRoutedSwapper indexed oldSwapper, IRoutedSwapper indexed newSwapper);

    constructor(
        address _pool,
        address _swapper,
        address _receiptToken
    ) {
        require(_pool != address(0), "pool-address-is-zero");
        require(_swapper != address(0), "swapper-address-is-zero");
        swapper = IRoutedSwapper(_swapper);
        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");
    }

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

    /// @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 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 OnlyKeeper: Rebalance profit, loss and investment of this strategy.
     *  Calculate profit, loss and payback of this strategy and realize profit/loss and
     *  withdraw fund for payback, if any, and submit this report to pool.
     * @return _profit Realized profit in collateral.
     * @return _loss Realized loss, if any, in collateral.
     * @return _payback If strategy has any excess debt, we have to liquidate asset to payback excess debt.
     */
    function rebalance()
        external
        onlyKeeper
        returns (
            uint256 _profit,
            uint256 _loss,
            uint256 _payback
        )
    {
        return _rebalance();
    }

    /**
     * @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 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 receipt token
    function token() external view override returns (address) {
        return receiptToken;
    }

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

    /// @notice Returns total collateral locked in the strategy
    function tvl() external view virtual returns (uint256);

    /**
     * @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 swapper
     * @param _swapper swapper address
     */
    function updateSwapper(IRoutedSwapper _swapper) external onlyGovernor {
        require(address(_swapper) != address(0), "swapper-address-is-zero");
        require(_swapper != swapper, "swapper-is-same");
        emit UpdatedSwapper(swapper, _swapper);
        swapper = _swapper;
    }

    /**
     * @notice Withdraw collateral token from end protocol.
     * @param _amount Amount of collateral token
     */
    function withdraw(uint256 _amount) external override onlyPool {
        uint256 _collateralHere = collateralToken.balanceOf(address(this));
        if (_collateralHere >= _amount) {
            collateralToken.safeTransfer(pool, _amount);
        } else {
            _withdrawHere(_amount - _collateralHere);
            // Do not assume _withdrawHere() will withdraw exact amount. Check balance again and transfer to pool
            _collateralHere = collateralToken.balanceOf(address(this));
            collateralToken.safeTransfer(pool, Math.min(_amount, _collateralHere));
        }
    }

    function _approveToken(uint256 _amount) internal virtual {
        collateralToken.safeApprove(pool, _amount);
    }

    /**
     * @dev 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;

    function _rebalance()
        internal
        virtual
        returns (
            uint256 _profit,
            uint256 _loss,
            uint256 _payback
        );

    function _swapExactInput(
        address _tokenIn,
        address _tokenOut,
        uint256 _amountIn
    ) internal returns (uint256 _amountOut) {
        _amountOut = swapper.swapExactInput(_tokenIn, _tokenOut, _amountIn, 1, address(this));
    }

    function _safeSwapExactInput(
        address _tokenIn,
        address _tokenOut,
        uint256 _amountIn
    ) internal {
        try swapper.swapExactInput(_tokenIn, _tokenOut, _amountIn, 1, address(this)) {} catch {} //solhint-disable no-empty-blocks
    }

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

// File: vesper-strategies/contracts/strategies/compound/CompoundVesperXy.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.8.9;

import "vesper-pools/contracts/interfaces/vesper/IPoolRewards.sol";
import "./CompoundXy.sol";

/// @title Deposit Collateral in Compound and earn interest by depositing borrowed token in a Vesper Pool.
contract CompoundVesperXy is CompoundXy {
    using SafeERC20 for IERC20;

    // Destination Grow Pool for borrowed Token
    IVesperPool public immutable vPool;
    // VSP token address
    address public immutable vsp;

    constructor(
        address _pool,
        address _swapper,
        address _comptroller,
        address _rewardToken,
        address _receiptToken,
        address _borrowCToken,
        address _vPool,
        address _vsp,
        string memory _name
    ) CompoundXy(_pool, _swapper, _comptroller, _rewardToken, _receiptToken, _borrowCToken, _name) {
        require(_vsp != address(0), "vsp-address-is-zero");
        require(address(IVesperPool(_vPool).token()) == borrowToken, "invalid-grow-pool");
        vPool = IVesperPool(_vPool);
        vsp = _vsp;
    }

    /// @notice Gets amount of borrowed Y collateral in strategy + Y collateral amount deposited in vPool
    function borrowBalance() external view returns (uint256) {
        return _getBorrowBalance();
    }

    /// @notice Claim VSP and convert to collateral token
    function harvestVSP() external {
        address _poolRewards = vPool.poolRewards();
        if (_poolRewards != address(0)) {
            IPoolRewards(_poolRewards).claimReward(address(this));
        }
        uint256 _vspAmount = IERC20(vsp).balanceOf(address(this));
        if (_vspAmount > 0) {
            _swapExactInput(vsp, address(collateralToken), _vspAmount);
        }
    }

    function isReservedToken(address _token) public view virtual override returns (bool) {
        return super.isReservedToken(_token) || _token == address(vPool);
    }

    /// @notice After borrowing Y, deposit to Vesper Pool
    function _afterBorrowY(uint256 _amount) internal override {
        vPool.deposit(_amount);
    }

    function _approveToken(uint256 _amount) internal override {
        super._approveToken(_amount);
        IERC20(borrowToken).safeApprove(address(vPool), _amount);
        IERC20(vsp).safeApprove(address(swapper), _amount);
    }

    /// @notice Before repaying Y, withdraw it from Vesper Pool
    function _beforeRepayY(uint256 _amount) internal override {
        _withdrawFromPool(_amount);
    }

    /// @notice Borrowed Y balance deposited in Vesper Pool
    function _getBorrowBalance() internal view override returns (uint256) {
        return
            IERC20(borrowToken).balanceOf(address(this)) +
            ((vPool.pricePerShare() * vPool.balanceOf(address(this))) / 1e18);
    }

    function _rebalanceBorrow(uint256 _excessBorrow) internal override {
        if (_excessBorrow > 0) {
            uint256 _borrowedHereBefore = IERC20(borrowToken).balanceOf(address(this));
            _withdrawFromPool(_excessBorrow);
            uint256 _borrowedHere = IERC20(borrowToken).balanceOf(address(this)) - _borrowedHereBefore;
            if (_borrowedHere > 0) {
                _safeSwapExactInput(borrowToken, address(collateralToken), _borrowedHere);
            }
        }
    }

    /// @notice Withdraw _shares proportional to collateral _amount from vPool
    function _withdrawFromPool(uint256 _amount) internal {
        uint256 _pricePerShare = vPool.pricePerShare();
        uint256 _shares = (_amount * 1e18) / _pricePerShare;
        _shares = _amount > ((_shares * _pricePerShare) / 1e18) ? _shares + 1 : _shares;

        uint256 _maxShares = vPool.balanceOf(address(this));
        vPool.withdraw(_shares > _maxShares ? _maxShares : _shares);
    }
}

// File: vesper-strategies/contracts/strategies/compound/CompoundXy.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.8.9;

import "vesper-pools/contracts/interfaces/token/IToken.sol";
import "./CompoundXyCore.sol";
import "../../interfaces/compound/ICompound.sol";

/// @title This strategy will deposit collateral token in Compound and based on position it will borrow
/// another token. Supply X borrow Y and keep borrowed amount here. It does handle rewards and handle
/// wrap/unwrap of WETH as ETH is required to interact with Compound.
contract CompoundXy is CompoundXyCore {
    using SafeERC20 for IERC20;

    address public immutable rewardToken;
    address internal constant WETH = 0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2;
    address private constant CETH = 0x4Ddc2D193948926D02f9B1fE9e1daa0718270ED5;

    constructor(
        address _pool,
        address _swapper,
        address _comptroller,
        address _rewardToken,
        address _receiptToken,
        address _borrowCToken,
        string memory _name
    ) CompoundXyCore(_pool, _swapper, _comptroller, _receiptToken, _borrowCToken, _name) {
        require(_rewardToken != address(0), "rewardToken-address-is-zero");
        rewardToken = _rewardToken;
    }

    //solhint-disable-next-line no-empty-blocks
    receive() external payable {}

    function _approveToken(uint256 _amount) internal virtual override {
        super._approveToken(_amount);
        IERC20(rewardToken).safeApprove(address(swapper), _amount);
    }

    /// @dev If borrowToken WETH then wrap borrowed ETH to get WETH
    function _borrowY(uint256 _amount) internal override {
        if (_amount > 0) {
            require(borrowCToken.borrow(_amount) == 0, "borrow-from-compound-failed");
            if (borrowToken == WETH) {
                TokenLike(WETH).deposit{value: address(this).balance}();
            }
            _afterBorrowY(_amount);
        }
    }

    /// @notice Claim rewardToken and convert rewardToken into collateral token.
    function _claimRewardsAndConvertTo(address _toToken) internal virtual override {
        address[] memory _markets = new address[](2);
        _markets[0] = address(supplyCToken);
        _markets[1] = address(borrowCToken);
        comptroller.claimComp(address(this), _markets);
        uint256 _rewardAmount = IERC20(rewardToken).balanceOf(address(this));
        if (_rewardAmount > 0) {
            _safeSwapExactInput(rewardToken, _toToken, _rewardAmount);
        }
    }

    /// @dev Native Compound cETH doesn't has underlying method
    function _getUnderlyingToken(address _cToken) internal view virtual override returns (address) {
        if (_cToken == CETH) {
            return WETH;
        }
        return CToken(_cToken).underlying();
    }

    /// @dev If borrowToken is WETH then unwrap WETH to get ETH and repay borrow using ETH.
    function _repayY(uint256 _amount) internal override {
        _beforeRepayY(_amount);
        if (borrowToken == WETH) {
            TokenLike(WETH).withdraw(_amount);
            borrowCToken.repayBorrow{value: _amount}();
        } else {
            require(borrowCToken.repayBorrow(_amount) == 0, "repay-to-compound-failed");
        }
    }
}

// File: vesper-strategies/contracts/strategies/compound/CompoundXyCore.sol



// SPDX-License-Identifier: MIT

pragma solidity 0.8.9;

import "vesper-pools/contracts/dependencies/openzeppelin/contracts/utils/math/Math.sol";
import "../Strategy.sol";
import "../../interfaces/compound/ICompound.sol";

// solhint-disable no-empty-blocks

/// @title This strategy will deposit collateral token in Compound and based on position it will
/// borrow another token. Supply X borrow Y and keep borrowed amount here.
/// It does not handle rewards and ETH as collateral
abstract contract CompoundXyCore is Strategy {
    using SafeERC20 for IERC20;
    // solhint-disable-next-line var-name-mixedcase
    string public NAME;
    string public constant VERSION = "5.0.0";

    uint256 internal constant MAX_BPS = 10_000; //100%
    uint32 internal constant TWAP_PERIOD = 3_600;
    uint256 public minBorrowLimit = 7_000; // 70% of actual collateral factor of protocol
    uint256 public maxBorrowLimit = 8_500; // 85% of actual collateral factor of protocol
    address public borrowToken;

    Comptroller public comptroller;

    CToken public immutable supplyCToken;
    CToken public immutable borrowCToken;

    event UpdatedBorrowLimit(
        uint256 previousMinBorrowLimit,
        uint256 newMinBorrowLimit,
        uint256 previousMaxBorrowLimit,
        uint256 newMaxBorrowLimit
    );

    constructor(
        address _pool,
        address _swapper,
        address _comptroller,
        address _receiptToken,
        address _borrowCToken,
        string memory _name
    ) Strategy(_pool, _swapper, _receiptToken) {
        require(_receiptToken != address(0), "cToken-address-is-zero");
        require(_comptroller != address(0), "comptroller-address-is-zero");

        NAME = _name;

        comptroller = Comptroller(_comptroller);
        supplyCToken = CToken(_receiptToken);
        borrowCToken = CToken(_borrowCToken);
        borrowToken = _getUnderlyingToken(_borrowCToken);

        address[] memory _cTokens = new address[](2);
        _cTokens[0] = _receiptToken;
        _cTokens[1] = _borrowCToken;
        comptroller.enterMarkets(_cTokens);
    }

    function isReservedToken(address _token) public view virtual override returns (bool) {
        return _token == address(supplyCToken) || _token == address(collateralToken) || _token == borrowToken;
    }

    /// @notice Returns total collateral locked in the strategy
    function tvl() external view override returns (uint256) {
        uint256 _collateralInCompound = (supplyCToken.balanceOf(address(this)) * supplyCToken.exchangeRateStored()) /
            1e18;
        return _collateralInCompound + collateralToken.balanceOf(address(this));
    }

    /// @dev Hook that executes after collateral borrow.
    function _afterBorrowY(uint256 _amount) internal virtual {}

    /// @notice Approve all required tokens
    function _approveToken(uint256 _amount) internal virtual override {
        super._approveToken(_amount);
        collateralToken.safeApprove(address(supplyCToken), _amount);
        collateralToken.safeApprove(address(swapper), _amount);
        IERC20(borrowToken).safeApprove(address(borrowCToken), _amount);
        IERC20(borrowToken).safeApprove(address(swapper), _amount);
    }

    /**
     * @notice Claim rewardToken and transfer to new strategy
     * @param _newStrategy Address of new strategy.
     */
    function _beforeMigration(address _newStrategy) internal override {
        require(IStrategy(_newStrategy).token() == address(supplyCToken), "wrong-receipt-token");
        _repay(borrowCToken.borrowBalanceCurrent(address(this)), false);
    }

    /// @dev Hook that executes before repaying borrowed collateral
    function _beforeRepayY(uint256 _amount) internal virtual {}

    /// @dev Borrow Y from Compound. _afterBorrowY hook can be used to do anything with borrowed amount.
    /// @dev Override to handle ETH
    function _borrowY(uint256 _amount) internal virtual {
        if (_amount > 0) {
            require(borrowCToken.borrow(_amount) == 0, "borrow-failed");
            _afterBorrowY(_amount);
        }
    }

    /**
     * @notice Calculate borrow and repay amount based on current collateral and new deposit/withdraw amount.
     * @param _depositAmount deposit amount
     * @param _withdrawAmount withdraw amount
     * @return _borrowAmount borrow more amount
     * @return _repayAmount repay amount to keep ltv within limit
     */
    function _calculateBorrowPosition(uint256 _depositAmount, uint256 _withdrawAmount)
        internal
        returns (uint256 _borrowAmount, uint256 _repayAmount)
    {
        require(_depositAmount == 0 || _withdrawAmount == 0, "all-input-gt-zero");
        uint256 _borrowed = borrowCToken.borrowBalanceCurrent(address(this));
        // If maximum borrow limit set to 0 then repay borrow
        if (maxBorrowLimit == 0) {
            return (0, _borrowed);
        }

        uint256 _collateral = supplyCToken.balanceOfUnderlying(address(this));
        uint256 _collateralFactor = _getCollateralFactor(address(supplyCToken));
        // In case of withdraw, _amount can be greater than _supply
        uint256 _hypotheticalCollateral;
        if (_depositAmount > 0) {
            _hypotheticalCollateral = _collateral + _depositAmount;
        } else if (_collateral > _withdrawAmount) {
            _hypotheticalCollateral = _collateral - _withdrawAmount;
        }

        // Calculate max borrow based on collateral factor
        uint256 _maxCollateralForBorrow = (_hypotheticalCollateral * _collateralFactor) / 1e18;
        Oracle _oracle = Oracle(comptroller.oracle());

        // Compound "UnderlyingPrice" decimal = (30 + 6 - tokenDecimal)
        // Rari "UnderlyingPrice" decimal = (30 + 6 - tokenDecimal)
        // Iron "UnderlyingPrice" decimal = (18 + 8 - tokenDecimal)
        uint256 _collateralTokenPrice = _oracle.getUnderlyingPrice(address(supplyCToken));
        uint256 _borrowTokenPrice = _oracle.getUnderlyingPrice(address(borrowCToken));
        // Max borrow limit in borrow token
        uint256 _maxBorrowPossible = (_maxCollateralForBorrow * _collateralTokenPrice) / _borrowTokenPrice;
        // If maxBorrow is zero, we should repay total amount of borrow
        if (_maxBorrowPossible == 0) {
            return (0, _borrowed);
        }

        // Safe buffer to avoid liquidation due to price variations.
        uint256 _borrowUpperBound = (_maxBorrowPossible * maxBorrowLimit) / MAX_BPS;

        // Borrow up to _borrowLowerBound and keep buffer of _borrowUpperBound - _borrowLowerBound for price variation
        uint256 _borrowLowerBound = (_maxBorrowPossible * minBorrowLimit) / MAX_BPS;

        // If current borrow is greater than max borrow, then repay to achieve safe position else borrow more.
        if (_borrowed > _borrowUpperBound) {
            // If borrow > upperBound then it is greater than lowerBound too.
            _repayAmount = _borrowed - _borrowLowerBound;
        } else if (_borrowLowerBound > _borrowed) {
            _borrowAmount = _borrowLowerBound - _borrowed;
            uint256 _availableLiquidity = _getAvailableLiquidity();
            if (_borrowAmount > _availableLiquidity) {
                _borrowAmount = _availableLiquidity;
            }
        }
    }

    function _claimRewardsAndConvertTo(address _toToken) internal virtual;

    /// @dev Deposit collateral in Compound and adjust borrow position
    function _deposit() internal {
        uint256 _collateralBalance = collateralToken.balanceOf(address(this));
        (uint256 _borrowAmount, uint256 _repayAmount) = _calculateBorrowPosition(_collateralBalance, 0);
        if (_repayAmount > 0) {
            // Repay to maintain safe position
            _repay(_repayAmount, false);
            _mintX(collateralToken.balanceOf(address(this)));
        } else {
            // Happy path, mint more borrow more
            _mintX(_collateralBalance);
            _borrowY(_borrowAmount);
        }
    }

    function _getAvailableLiquidity() internal view virtual returns (uint256) {
        return borrowCToken.getCash();
    }

    /// @dev Get the borrow balance strategy is holding. Override to handle vToken balance.
    function _getBorrowBalance() internal view virtual returns (uint256) {
        return IERC20(borrowToken).balanceOf(address(this));
    }

    /// @dev TraderJoe Compound fork has different markets API so allow this method to override.
    function _getCollateralFactor(address _cToken) internal view virtual returns (uint256 _collateralFactor) {
        (, _collateralFactor, ) = comptroller.markets(_cToken);
    }

    /// @dev Get underlying token. Compound handle ETH differently hence allow this method to override
    function _getUnderlyingToken(address _cToken) internal view virtual returns (address) {
        return CToken(_cToken).underlying();
    }

    /// @dev Deposit collateral aka X in Compound. Override to handle ETH
    function _mintX(uint256 _amount) internal virtual {
        if (_amount > 0) {
            require(supplyCToken.mint(_amount) == 0, "supply-failed");
        }
    }

    function _rebalance()
        internal
        override
        returns (
            uint256 _profit,
            uint256 _loss,
            uint256 _payback
        )
    {
        uint256 _excessDebt = IVesperPool(pool).excessDebt(address(this));
        uint256 _totalDebt = IVesperPool(pool).totalDebtOf(address(this));
        // Claim any reward we have.
        _claimRewardsAndConvertTo(address(collateralToken));
        uint256 _borrow = borrowCToken.borrowBalanceCurrent(address(this));
        uint256 _borrowBalanceHere = _getBorrowBalance();
        // _borrow increases every block. Convert collateral to borrowToken.
        if (_borrow > _borrowBalanceHere) {
            _swapToBorrowToken(_borrow - _borrowBalanceHere);
        } else {
            // When _borrowBalanceHere exceeds _borrow balance from Compound
            // Customize this hook to handle the excess borrowToken profit
            _rebalanceBorrow(_borrowBalanceHere - _borrow);
        }

        uint256 _collateralHere = collateralToken.balanceOf(address(this));
        uint256 _collateralInCompound = supplyCToken.balanceOfUnderlying(address(this));
        uint256 _totalCollateral = _collateralInCompound + _collateralHere;

        if (_totalCollateral > _totalDebt) {
            _profit = _totalCollateral - _totalDebt;
        } else {
            _loss = _totalDebt - _totalCollateral;
        }
        uint256 _profitAndExcessDebt = _profit + _excessDebt;
        if (_collateralHere < _profitAndExcessDebt) {
            uint256 _totalAmountToWithdraw = Math.min((_profitAndExcessDebt - _collateralHere), _collateralInCompound);
            if (_totalAmountToWithdraw > 0) {
                _withdrawHere(_totalAmountToWithdraw);
                _collateralHere = collateralToken.balanceOf(address(this));
            }
        }

        // Set actual payback first and then profit. Make sure _collateralHere >= _payback + profit.
        _payback = Math.min(_collateralHere, _excessDebt);
        _profit = _collateralHere > _payback ? Math.min((_collateralHere - _payback), _profit) : 0;

        IVesperPool(pool).reportEarning(_profit, _loss, _payback);
        _deposit();
    }

    /// @dev Hook to handle profit scenario i.e. actual borrowed balance > Compound borrow account.
    function _rebalanceBorrow(uint256 _excessBorrow) internal virtual {}

    /// @dev Withdraw collateral aka X from Compound. Override to handle ETH
    function _redeemX(uint256 _amount) internal virtual {
        require(supplyCToken.redeemUnderlying(_amount) == 0, "withdraw-failed");
    }

    /**
     * @dev Repay borrow amount
     * @dev Claim rewardToken and convert to collateral. Swap collateral to borrowToken as needed.
     * @param _repayAmount BorrowToken amount that we should repay to maintain safe position.
     * @param _shouldClaimComp Flag indicating should we claim rewardToken and convert to collateral or not.
     */
    function _repay(uint256 _repayAmount, bool _shouldClaimComp) internal {
        if (_repayAmount > 0) {
            uint256 _borrowBalanceHere = _getBorrowBalance();
            // Liability is more than what we have.
            // To repay loan - convert all rewards to collateral, if asked, and redeem collateral(if needed).
            // This scenario is rare and if system works okay it will/might happen during final repay only.
            if (_repayAmount > _borrowBalanceHere) {
                if (_shouldClaimComp) {
                    // Claim rewardToken and convert those to collateral.
                    _claimRewardsAndConvertTo(address(collateralToken));
                }

                uint256 _currentBorrow = borrowCToken.borrowBalanceCurrent(address(this));
                // For example this is final repay and 100 blocks has passed since last withdraw/rebalance,
                // _currentBorrow is increasing due to interest. Now if _repayAmount > _borrowBalanceHere is true
                // _currentBorrow > _borrowBalanceHere is also true.
                // To maintain safe position we always try to keep _currentBorrow = _borrowBalanceHere

                // Swap collateral to borrowToken to repay borrow and also maintain safe position
                // Here borrowToken amount needed is (_currentBorrow - _borrowBalanceHere)
                _swapToBorrowToken(_currentBorrow - _borrowBalanceHere);
            }
            _repayY(_repayAmount);
        }
    }

    /// @dev Repay Y to Compound. _beforeRepayY hook can be used for pre-repay actions.
    /// @dev Override this to handle ETH
    function _repayY(uint256 _amount) internal virtual {
        _beforeRepayY(_amount);
        require(borrowCToken.repayBorrow(_amount) == 0, "repay-failed");
    }

    /**
     * @dev Swap given token to borrowToken
     * @param _shortOnBorrow Expected output of this swap
     */
    function _swapToBorrowToken(uint256 _shortOnBorrow) internal {
        // Looking for _amountIn using fixed output amount
        uint256 _amountIn = swapper.getAmountIn(address(collateralToken), borrowToken, _shortOnBorrow);
        if (_amountIn > 0) {
            uint256 _collateralHere = collateralToken.balanceOf(address(this));
            // If we do not have enough _from token to get expected output, either get
            // some _from token or adjust expected output.
            if (_amountIn > _collateralHere) {
                // Redeem some collateral, so that we have enough collateral to get expected output
                _redeemX(_amountIn - _collateralHere);
            }
            swapper.swapExactOutput(address(collateralToken), borrowToken, _shortOnBorrow, _amountIn, address(this));
        }
    }

    /// @dev Withdraw collateral here. Do not transfer to pool
    function _withdrawHere(uint256 _amount) internal override {
        (, uint256 _repayAmount) = _calculateBorrowPosition(0, _amount);
        _repay(_repayAmount, true);
        uint256 _supply = supplyCToken.balanceOfUnderlying(address(this));
        _redeemX(_supply > _amount ? _amount : _supply);
    }

    /************************************************************************************************
     *                          Governor/admin/keeper function                                      *
     ***********************************************************************************************/
    /**
     * @notice Recover extra borrow tokens from strategy
     * @dev If we get liquidation in Compound, we will have borrowToken sitting in strategy.
     * This function allows to recover idle borrow token amount.
     * @param _amountToRecover Amount of borrow token we want to recover in 1 call.
     *      Set it 0 to recover all available borrow tokens
     */
    function recoverBorrowToken(uint256 _amountToRecover) external onlyKeeper {
        uint256 _borrowBalanceHere = IERC20(borrowToken).balanceOf(address(this));
        uint256 _borrowInCompound = borrowCToken.borrowBalanceStored(address(this));

        if (_borrowBalanceHere > _borrowInCompound) {
            uint256 _extraBorrowBalance = _borrowBalanceHere - _borrowInCompound;
            uint256 _recoveryAmount = (_amountToRecover > 0 && _extraBorrowBalance > _amountToRecover)
                ? _amountToRecover
                : _extraBorrowBalance;
            // Do swap and transfer
            uint256 _collateralBefore = collateralToken.balanceOf(address(this));
            _safeSwapExactInput(borrowToken, address(collateralToken), _recoveryAmount);
            collateralToken.transfer(pool, collateralToken.balanceOf(address(this)) - _collateralBefore);
        }
    }

    /**
     * @notice Repay all borrow amount and set min borrow limit to 0.
     * @dev This action usually done when loss is detected in strategy.
     * @dev 0 borrow limit make sure that any future rebalance do not borrow again.
     */
    function repayAll() external onlyKeeper {
        _repay(borrowCToken.borrowBalanceCurrent(address(this)), true);
        minBorrowLimit = 0;
        maxBorrowLimit = 0;
    }

    /**
     * @notice Update upper and lower borrow limit. Usually maxBorrowLimit < 100% of actual collateral factor of protocol.
     * @dev It is possible to set 0 as _minBorrowLimit to not borrow anything
     * @param _minBorrowLimit It is % of actual collateral factor of protocol
     * @param _maxBorrowLimit It is % of actual collateral factor of protocol
     */
    function updateBorrowLimit(uint256 _minBorrowLimit, uint256 _maxBorrowLimit) external onlyGovernor {
        require(_maxBorrowLimit < MAX_BPS, "invalid-max-borrow-limit");
        // set _maxBorrowLimit and _minBorrowLimit to zero to disable borrow;
        require(
            (_maxBorrowLimit == 0 && _minBorrowLimit == 0) || _maxBorrowLimit > _minBorrowLimit,
            "max-should-be-higher-than-min"
        );
        emit UpdatedBorrowLimit(minBorrowLimit, _minBorrowLimit, maxBorrowLimit, _maxBorrowLimit);
        // To avoid liquidation due to price variations maxBorrowLimit is a collateral factor that is less than actual collateral factor of protocol
        minBorrowLimit = _minBorrowLimit;
        maxBorrowLimit = _maxBorrowLimit;
    }
}