Farming of Trade WETH v3

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @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
     *
     * Furthermore, `isContract` will also return true if the target contract within
     * the same transaction is already scheduled for destruction by `SELFDESTRUCT`,
     * which only has an effect at the end of a transaction.
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 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://consensys.net/diligence/blog/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/v0.8.0/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");

        (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 functionCallWithValue(target, data, 0, "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");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, 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) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, 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) {
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
     * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
     *
     * _Available since v4.8._
     */
    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        if (success) {
            if (returndata.length == 0) {
                // only check isContract if the call was successful and the return data is empty
                // otherwise we already know that it was a contract
                require(isContract(target), "Address: call to non-contract");
            }
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    /**
     * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason or using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    function _revert(bytes memory returndata, string memory errorMessage) private pure {
        // 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
            /// @solidity memory-safe-assembly
            assembly {
                let returndata_size := mload(returndata)
                revert(add(32, returndata), returndata_size)
            }
        } else {
            revert(errorMessage);
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

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) {
        return msg.data;
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/ERC20.sol)

pragma solidity ^0.8.0;

import "./IERC20.sol";
import "./extensions/IERC20Metadata.sol";
import "../../utils/Context.sol";

/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20PresetMinterPauser}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.openzeppelin.com/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * The default value of {decimals} is 18. To change this, you should override
 * this function so it returns a different value.
 *
 * We have followed general OpenZeppelin Contracts guidelines: functions revert
 * instead returning `false` on failure. This behavior is nonetheless
 * conventional and does not conflict with the expectations of ERC20
 * applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20 is Context, IERC20, IERC20Metadata {
    mapping(address => uint256) private _balances;

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

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;

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

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

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

    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5.05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei. This is the default value returned by this function, unless
     * it's overridden.
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view virtual override returns (uint8) {
        return 18;
    }

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

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

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

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

    /**
     * @dev See {IERC20-approve}.
     *
     * NOTE: If `amount` is the maximum `uint256`, the allowance is not updated on
     * `transferFrom`. This is semantically equivalent to an infinite approval.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, amount);
        return true;
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20}.
     *
     * NOTE: Does not update the allowance if the current allowance
     * is the maximum `uint256`.
     *
     * Requirements:
     *
     * - `from` and `to` cannot be the zero address.
     * - `from` must have a balance of at least `amount`.
     * - the caller must have allowance for ``from``'s tokens of at least
     * `amount`.
     */
    function transferFrom(address from, address to, uint256 amount) public virtual override returns (bool) {
        address spender = _msgSender();
        _spendAllowance(from, spender, amount);
        _transfer(from, to, amount);
        return true;
    }

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

    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        address owner = _msgSender();
        uint256 currentAllowance = allowance(owner, spender);
        require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
        unchecked {
            _approve(owner, spender, currentAllowance - subtractedValue);
        }

        return true;
    }

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

        _beforeTokenTransfer(from, to, amount);

        uint256 fromBalance = _balances[from];
        require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
        unchecked {
            _balances[from] = fromBalance - amount;
            // Overflow not possible: the sum of all balances is capped by totalSupply, and the sum is preserved by
            // decrementing then incrementing.
            _balances[to] += amount;
        }

        emit Transfer(from, to, amount);

        _afterTokenTransfer(from, to, amount);
    }

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

        _beforeTokenTransfer(address(0), account, amount);

        _totalSupply += amount;
        unchecked {
            // Overflow not possible: balance + amount is at most totalSupply + amount, which is checked above.
            _balances[account] += amount;
        }
        emit Transfer(address(0), account, amount);

        _afterTokenTransfer(address(0), account, amount);
    }

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

        _beforeTokenTransfer(account, address(0), amount);

        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
        unchecked {
            _balances[account] = accountBalance - amount;
            // Overflow not possible: amount <= accountBalance <= totalSupply.
            _totalSupply -= amount;
        }

        emit Transfer(account, address(0), amount);

        _afterTokenTransfer(account, address(0), amount);
    }

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

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

    /**
     * @dev Updates `owner` s allowance for `spender` based on spent `amount`.
     *
     * Does not update the allowance amount in case of infinite allowance.
     * Revert if not enough allowance is available.
     *
     * Might emit an {Approval} event.
     */
    function _spendAllowance(address owner, address spender, uint256 amount) internal virtual {
        uint256 currentAllowance = allowance(owner, spender);
        if (currentAllowance != type(uint256).max) {
            require(currentAllowance >= amount, "ERC20: insufficient allowance");
            unchecked {
                _approve(owner, spender, currentAllowance - amount);
            }
        }
    }

    /**
     * @dev Hook that is called before any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * will be transferred to `to`.
     * - when `from` is zero, `amount` tokens will be minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual {}

    /**
     * @dev Hook that is called after any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * has been transferred to `to`.
     * - when `from` is zero, `amount` tokens have been minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens have been burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _afterTokenTransfer(address from, address to, uint256 amount) internal virtual {}
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import { Math } from "@openzeppelin/contracts/utils/math/Math.sol";

library FarmAccounting {
    error ZeroDuration();
    error DurationTooLarge();
    error AmountTooLarge();

    struct Info {
        uint40 finished;
        uint32 duration;
        uint184 reward;
        uint256 balance;
    }

    uint256 internal constant _MAX_REWARD_AMOUNT = 1e32;  // 108 bits
    uint256 internal constant _SCALE = 1e18;  // 60 bits

    /// @dev Requires extra 18 decimals for precision, result fits in 168 bits
    function farmedSinceCheckpointScaled(Info storage info, uint256 checkpoint) internal view returns(uint256 amount) {
        unchecked {
            (uint40 finished, uint32 duration, uint184 reward) = (info.finished, info.duration, info.reward);
            if (duration > 0) {
                uint256 elapsed = Math.min(block.timestamp, finished) - Math.min(checkpoint, finished);
                // size of (type(uint32).max * _MAX_REWARD_AMOUNT * _SCALE) is less than 200 bits, so there is no overflow
                return elapsed * reward * _SCALE / duration;
            }
        }
    }

    function startFarming(Info storage info, uint256 amount, uint256 period) internal returns(uint256) {
        if (period == 0) revert ZeroDuration();
        if (period > type(uint32).max) revert DurationTooLarge();

        // If something left from prev farming add it to the new farming
        (uint40 finished, uint32 duration, uint184 reward, uint256 balance) = (info.finished, info.duration, info.reward, info.balance);
        if (block.timestamp < finished) {
            amount += reward - farmedSinceCheckpointScaled(info, finished - duration) / _SCALE;
        }

        if (amount > _MAX_REWARD_AMOUNT) revert AmountTooLarge();

        (info.finished, info.duration, info.reward, info.balance) = (
            uint40(block.timestamp + period),
            uint32(period),
            uint184(amount),
            balance + amount
        );
        return amount;
    }

    function stopFarming(Info storage info) internal returns(uint256 leftover) {
        leftover = info.reward - farmedSinceCheckpointScaled(info, info.finished - info.duration) / _SCALE;
        (info.finished, info.duration, info.reward, info.balance) = (
            uint40(block.timestamp),
            uint32(0),
            uint184(0),
            info.balance - leftover
        );
    }

    function claim(Info storage info, uint256 amount) internal {
        info.balance -= amount;
    }
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import { FarmAccounting } from "./accounting/FarmAccounting.sol";
import { UserAccounting } from "./accounting/UserAccounting.sol";

/// @title FarmingLib
/// @dev A library for farming logic, using FarmAccounting and UserAccounting.
library FarmingLib {
    using FarmAccounting for FarmAccounting.Info;
    using UserAccounting for UserAccounting.Info;
    using FarmingLib for FarmingLib.Info;

    /// @dev Struct containing farm and user detailed info for farming operations. See {FarmAccounting.Info} and {UserAccounting.Info} for.
    struct Data {
        FarmAccounting.Info farmInfo;
        UserAccounting.Info userInfo;
    }

    /// @dev Struct containing the total supply function and a data slot for EVM storage.
    struct Info {
        function() internal view returns(uint256) getTotalSupply;
        bytes32 dataSlot;
    }

    /**
     * @notice Creates a new Info struct.
     * @param getTotalSupply The function to get the total supply.
     * @param data The data struct for storage.
     * @return info The created Info struct.
     */
    function makeInfo(function() internal view returns(uint256) getTotalSupply, Data storage data) internal pure returns(Info memory info) {
        info.getTotalSupply = getTotalSupply;
        bytes32 dataSlot;
        assembly ("memory-safe") {  // solhint-disable-line no-inline-assembly
            dataSlot := data.slot
        }
        info.dataSlot = dataSlot;
    }

    /**
     * @notice Retrieves the Data struct from an Info struct.
     * @param self The Info struct.
     * @return data The retrieved Data struct.
     */
    function getData(Info memory self) internal pure returns(Data storage data) {
        bytes32 dataSlot = self.dataSlot;
        assembly ("memory-safe") {  // solhint-disable-line no-inline-assembly
            data.slot := dataSlot
        }
    }

    /**
     * @notice Begins farming for a specified period.
     * @param self The Info struct.
     * @param amount The amount to farm.
     * @param period The farming period.
     * @return reward The farming reward.
     */
    function startFarming(Info memory self, uint256 amount, uint256 period) internal returns(uint256 reward) {
        Data storage data = self.getData();
        data.userInfo.updateFarmedPerToken(_farmedPerToken(self));
        reward = data.farmInfo.startFarming(amount, period);
    }

    /**
     * @notice Stops farming immediately.
     * @param self The FarmingLib.Info struct to retrieve data from storage.
     * @return leftover Amount of reward tokens remaining after farming.
     */
    function stopFarming(Info memory self) internal returns(uint256 leftover) {
        Data storage data = self.getData();
        data.userInfo.updateFarmedPerToken(_farmedPerToken(self));
        leftover = data.farmInfo.stopFarming();
    }

    /**
     * @notice Gets the farmed amount for an account.
     * @param self The Info struct.
     * @param account The account to check.
     * @param balance The account balance.
     * @return result The farmed amount.
     */
    function farmed(Info memory self, address account, uint256 balance) internal view returns(uint256) {
        return self.getData().userInfo.farmed(account, balance, _farmedPerToken(self));
    }

    /**
     * @notice Claims the farmed amount for an account.
     * @param self The Info struct.
     * @param account The account to claim for.
     * @param balance The account balance.
     * @return amount The claimed amount.
     */
    function claim(Info memory self, address account, uint256 balance) internal returns(uint256 amount) {
        Data storage data = self.getData();
        uint256 fpt = _farmedPerToken(self);
        amount = data.userInfo.farmed(account, balance, fpt);
        if (amount > 0) {
            data.userInfo.eraseFarmed(account, balance, fpt);
            data.farmInfo.claim(amount);
        }
    }

    /**
     * @notice Updates the balances of two accounts.
     * @param self The Info struct.
     * @param from The account to transfer from.
     * @param to The account to transfer to.
     * @param amount The amount to transfer.
     */
    function updateBalances(Info memory self, address from, address to, uint256 amount) internal {
        self.getData().userInfo.updateBalances(from, to, amount, _farmedPerToken(self));
    }

    function _farmedPerToken(Info memory self) private view returns (uint256) {
        return self.getData().userInfo.farmedPerToken(_infoToContext(self), _lazyGetSupply, _lazyGetFarmed);
    }

    // UserAccounting bindings

    function _lazyGetSupply(bytes32 context) private view returns(uint256) {
        Info memory self = _contextToInfo(context);
        return self.getTotalSupply();
    }

    function _lazyGetFarmed(bytes32 context, uint256 checkpoint) private view returns(uint256) {
        Info memory self = _contextToInfo(context);
        return self.getData().farmInfo.farmedSinceCheckpointScaled(checkpoint);
    }

    function _contextToInfo(bytes32 context) private pure returns(Info memory self) {
        assembly ("memory-safe") {  // solhint-disable-line no-inline-assembly
            self := context
        }
    }

    function _infoToContext(Info memory self) private pure returns(bytes32 context) {
        assembly ("memory-safe") {  // solhint-disable-line no-inline-assembly
            context := self
        }
    }
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import { Ownable } from "@openzeppelin/contracts/access/Ownable.sol";
import { IERC20, ERC20 } from "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import { IERC20Metadata } from "@openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol";
import { Address } from "@openzeppelin/contracts/utils/Address.sol";
import { SafeERC20 } from "@1inch/solidity-utils/contracts/libraries/SafeERC20.sol";

import { IFarmingPool } from "./interfaces/IFarmingPool.sol";
import { FarmAccounting, FarmingLib } from "./FarmingLib.sol";

contract FarmingPool is IFarmingPool, Ownable, ERC20 {
    using SafeERC20 for IERC20;
    using Address for address payable;
    using FarmingLib for FarmingLib.Info;

    error SameStakingAndRewardsTokens();
    error ZeroStakingTokenAddress();
    error ZeroRewardsTokenAddress();
    error ZeroDistributorAddress();
    error SameDistributor();
    error AccessDenied();
    error InsufficientFunds();
    error MaxBalanceExceeded();

    uint256 internal constant _MAX_BALANCE = 1e32;

    IERC20 public immutable stakingToken;
    IERC20 public immutable rewardsToken;

    address private _distributor;
    FarmingLib.Data private _farm;

    modifier onlyDistributor {
        if (msg.sender != _distributor) revert AccessDenied();
        _;
    }

    constructor(IERC20Metadata stakingToken_, IERC20 rewardsToken_)
        ERC20(
            string(abi.encodePacked("Farming of ", stakingToken_.name())),
            string(abi.encodePacked("farm", stakingToken_.symbol()))
        )
    {
        if (stakingToken_ == rewardsToken_) revert SameStakingAndRewardsTokens();
        if (address(stakingToken_) == address(0)) revert ZeroStakingTokenAddress();
        if (address(rewardsToken_) == address(0)) revert ZeroRewardsTokenAddress();
        stakingToken = stakingToken_;
        rewardsToken = rewardsToken_;
    }

    function decimals() public view virtual override returns (uint8) {
        return IERC20Metadata(address(stakingToken)).decimals();
    }

    function farmInfo() public view returns(FarmAccounting.Info memory) {
        return _farm.farmInfo;
    }

    function distributor() public view virtual returns (address) {
        return _distributor;
    }

    function setDistributor(address distributor_) public virtual onlyOwner {
        if (distributor_ == address(0)) revert ZeroDistributorAddress();
        address oldDistributor = _distributor;
        if (distributor_ == oldDistributor) revert SameDistributor();
        emit DistributorChanged(oldDistributor, distributor_);
        _distributor = distributor_;
    }

    function startFarming(uint256 amount, uint256 period) public virtual onlyDistributor {
        uint256 reward = _makeInfo().startFarming(amount, period);
        emit RewardUpdated(reward, period);
        rewardsToken.safeTransferFrom(msg.sender, address(this), amount);
    }

    function stopFarming() public virtual onlyDistributor {
        uint256 leftover = _makeInfo().stopFarming();
        emit RewardUpdated(0, 0);
        if (leftover > 0) {
            rewardsToken.safeTransfer(msg.sender, leftover);
        }
    }

    function farmed(address account) public view virtual returns (uint256) {
        return _makeInfo().farmed(account, balanceOf(account));
    }

    function deposit(uint256 amount) public virtual {
        _mint(msg.sender, amount);
        if (balanceOf(msg.sender) > _MAX_BALANCE) revert MaxBalanceExceeded();
        stakingToken.safeTransferFrom(msg.sender, address(this), amount);
    }

    function withdraw(uint256 amount) public virtual {
        _burn(msg.sender, amount);
        stakingToken.safeTransfer(msg.sender, amount);
    }

    function claim() public virtual {
        uint256 amount = _makeInfo().claim(msg.sender, balanceOf(msg.sender));
        if (amount > 0) {
            _transferReward(rewardsToken, msg.sender, amount);
        }
    }

    function _transferReward(IERC20 reward, address to, uint256 amount) internal virtual {
        reward.safeTransfer(to, amount);
    }

    function exit() public virtual {
        withdraw(balanceOf(msg.sender));
        claim();
    }

    function rescueFunds(IERC20 token, uint256 amount) public virtual onlyDistributor {
        if (token == IERC20(address(0))) {
            payable(_distributor).sendValue(amount);
        } else {
            if (token == stakingToken) {
                if (stakingToken.balanceOf(address(this)) < totalSupply() + amount) revert InsufficientFunds();
            } else if (token == rewardsToken) {
                if (rewardsToken.balanceOf(address(this)) < _farm.farmInfo.balance + amount) revert InsufficientFunds();
            }

            token.safeTransfer(_distributor, amount);
        }
    }

    function _makeInfo() private view returns(FarmingLib.Info memory) {
        return FarmingLib.makeInfo(totalSupply, _farm);
    }

    // ERC20 overrides

    function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual override {
        super._beforeTokenTransfer(from, to, amount);

        if (amount > 0 && from != to) {
            _makeInfo().updateBalances(from, to, amount);
        }
    }
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

interface IDaiLikePermit {
    function permit(
        address holder,
        address spender,
        uint256 nonce,
        uint256 expiry,
        bool allowed,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

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

    /**
     * @dev 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 `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, 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 `from` to `to` 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 from, address to, uint256 amount) external returns (bool);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)

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);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/extensions/IERC20Permit.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 Permit extension allowing approvals to be made via signatures, as defined in
 * https://eips.ethereum.org/EIPS/eip-2612[EIP-2612].
 *
 * Adds the {permit} method, which can be used to change an account's ERC20 allowance (see {IERC20-allowance}) by
 * presenting a message signed by the account. By not relying on {IERC20-approve}, the token holder account doesn't
 * need to send a transaction, and thus is not required to hold Ether at all.
 */
interface IERC20Permit {
    /**
     * @dev Sets `value` as the allowance of `spender` over ``owner``'s tokens,
     * given ``owner``'s signed approval.
     *
     * IMPORTANT: The same issues {IERC20-approve} has related to transaction
     * ordering also apply here.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `deadline` must be a timestamp in the future.
     * - `v`, `r` and `s` must be a valid `secp256k1` signature from `owner`
     * over the EIP712-formatted function arguments.
     * - the signature must use ``owner``'s current nonce (see {nonces}).
     *
     * For more information on the signature format, see the
     * https://eips.ethereum.org/EIPS/eip-2612#specification[relevant EIP
     * section].
     */
    function permit(
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external;

    /**
     * @dev Returns the current nonce for `owner`. This value must be
     * included whenever a signature is generated for {permit}.
     *
     * Every successful call to {permit} increases ``owner``'s nonce by one. This
     * prevents a signature from being used multiple times.
     */
    function nonces(address owner) external view returns (uint256);

    /**
     * @dev Returns the domain separator used in the encoding of the signature for {permit}, as defined by {EIP712}.
     */
    // solhint-disable-next-line func-name-mixedcase
    function DOMAIN_SEPARATOR() external view returns (bytes32);
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import { IERC20 } from "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import { FarmAccounting } from "../accounting/FarmAccounting.sol";

interface IFarmingPool is IERC20 {
    event DistributorChanged(address oldDistributor, address newDistributor);
    event RewardUpdated(uint256 reward, uint256 duration);

    // View functions
    function distributor() external view returns(address);
    function farmInfo() external view returns(FarmAccounting.Info memory);
    function farmed(address account) external view returns(uint256);

    // User functions
    function deposit(uint256 amount) external;
    function withdraw(uint256 amount) external;
    function claim() external;
    function exit() external;

    // Owner functions
    function setDistributor(address distributor_) external;

    // Distributor functions
    function startFarming(uint256 amount, uint256 period) external;
    function rescueFunds(IERC20 token, uint256 amount) external;
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

interface IPermit2 {
    struct PermitDetails {
        // ERC20 token address
        address token;
        // the maximum amount allowed to spend
        uint160 amount;
        // timestamp at which a spender's token allowances become invalid
        uint48 expiration;
        // an incrementing value indexed per owner,token,and spender for each signature
        uint48 nonce;
    }
    /// @notice The permit message signed for a single token allownce
    struct PermitSingle {
        // the permit data for a single token alownce
        PermitDetails details;
        // address permissioned on the allowed tokens
        address spender;
        // deadline on the permit signature
        uint256 sigDeadline;
    }
    /// @notice Packed allowance
    struct PackedAllowance {
        // amount allowed
        uint160 amount;
        // permission expiry
        uint48 expiration;
        // an incrementing value indexed per owner,token,and spender for each signature
        uint48 nonce;
    }

    function transferFrom(address user, address spender, uint160 amount, address token) external;

    function permit(address owner, PermitSingle memory permitSingle, bytes calldata signature) external;

    function allowance(address user, address token, address spender) external view returns (PackedAllowance memory);
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

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

interface IWETH is IERC20 {
    event Deposit(address indexed dst, uint wad);

    event Withdrawal(address indexed src, uint wad);

    function deposit() external payable;

    function withdraw(uint256 amount) external;
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (utils/math/Math.sol)

pragma solidity ^0.8.0;

/**
 * @dev Standard math utilities missing in the Solidity language.
 */
library Math {
    enum Rounding {
        Down, // Toward negative infinity
        Up, // Toward infinity
        Zero // Toward zero
    }

    /**
     * @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.
        return (a & b) + (a ^ b) / 2;
    }

    /**
     * @dev Returns the ceiling of the division of two numbers.
     *
     * This differs from standard division with `/` in that it rounds up instead
     * of rounding down.
     */
    function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b - 1) / b can overflow on addition, so we distribute.
        return a == 0 ? 0 : (a - 1) / b + 1;
    }

    /**
     * @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or denominator == 0
     * @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv)
     * with further edits by Uniswap Labs also under MIT license.
     */
    function mulDiv(uint256 x, uint256 y, uint256 denominator) internal pure returns (uint256 result) {
        unchecked {
            // 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use
            // use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256
            // variables such that product = prod1 * 2^256 + prod0.
            uint256 prod0; // Least significant 256 bits of the product
            uint256 prod1; // Most significant 256 bits of the product
            assembly {
                let mm := mulmod(x, y, not(0))
                prod0 := mul(x, y)
                prod1 := sub(sub(mm, prod0), lt(mm, prod0))
            }

            // Handle non-overflow cases, 256 by 256 division.
            if (prod1 == 0) {
                // Solidity will revert if denominator == 0, unlike the div opcode on its own.
                // The surrounding unchecked block does not change this fact.
                // See https://docs.soliditylang.org/en/latest/control-structures.html#checked-or-unchecked-arithmetic.
                return prod0 / denominator;
            }

            // Make sure the result is less than 2^256. Also prevents denominator == 0.
            require(denominator > prod1, "Math: mulDiv overflow");

            ///////////////////////////////////////////////
            // 512 by 256 division.
            ///////////////////////////////////////////////

            // Make division exact by subtracting the remainder from [prod1 prod0].
            uint256 remainder;
            assembly {
                // Compute remainder using mulmod.
                remainder := mulmod(x, y, denominator)

                // Subtract 256 bit number from 512 bit number.
                prod1 := sub(prod1, gt(remainder, prod0))
                prod0 := sub(prod0, remainder)
            }

            // Factor powers of two out of denominator and compute largest power of two divisor of denominator. Always >= 1.
            // See https://cs.stackexchange.com/q/138556/92363.

            // Does not overflow because the denominator cannot be zero at this stage in the function.
            uint256 twos = denominator & (~denominator + 1);
            assembly {
                // Divide denominator by twos.
                denominator := div(denominator, twos)

                // Divide [prod1 prod0] by twos.
                prod0 := div(prod0, twos)

                // Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.
                twos := add(div(sub(0, twos), twos), 1)
            }

            // Shift in bits from prod1 into prod0.
            prod0 |= prod1 * twos;

            // Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such
            // that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for
            // four bits. That is, denominator * inv = 1 mod 2^4.
            uint256 inverse = (3 * denominator) ^ 2;

            // Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also works
            // in modular arithmetic, doubling the correct bits in each step.
            inverse *= 2 - denominator * inverse; // inverse mod 2^8
            inverse *= 2 - denominator * inverse; // inverse mod 2^16
            inverse *= 2 - denominator * inverse; // inverse mod 2^32
            inverse *= 2 - denominator * inverse; // inverse mod 2^64
            inverse *= 2 - denominator * inverse; // inverse mod 2^128
            inverse *= 2 - denominator * inverse; // inverse mod 2^256

            // Because the division is now exact we can divide by multiplying with the modular inverse of denominator.
            // This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is
            // less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1
            // is no longer required.
            result = prod0 * inverse;
            return result;
        }
    }

    /**
     * @notice Calculates x * y / denominator with full precision, following the selected rounding direction.
     */
    function mulDiv(uint256 x, uint256 y, uint256 denominator, Rounding rounding) internal pure returns (uint256) {
        uint256 result = mulDiv(x, y, denominator);
        if (rounding == Rounding.Up && mulmod(x, y, denominator) > 0) {
            result += 1;
        }
        return result;
    }

    /**
     * @dev Returns the square root of a number. If the number is not a perfect square, the value is rounded down.
     *
     * Inspired by Henry S. Warren, Jr.'s "Hacker's Delight" (Chapter 11).
     */
    function sqrt(uint256 a) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }

        // For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.
        //
        // We know that the "msb" (most significant bit) of our target number `a` is a power of 2 such that we have
        // `msb(a) <= a < 2*msb(a)`. This value can be written `msb(a)=2**k` with `k=log2(a)`.
        //
        // This can be rewritten `2**log2(a) <= a < 2**(log2(a) + 1)`
        // → `sqrt(2**k) <= sqrt(a) < sqrt(2**(k+1))`
        // → `2**(k/2) <= sqrt(a) < 2**((k+1)/2) <= 2**(k/2 + 1)`
        //
        // Consequently, `2**(log2(a) / 2)` is a good first approximation of `sqrt(a)` with at least 1 correct bit.
        uint256 result = 1 << (log2(a) >> 1);

        // At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,
        // since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at
        // every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision
        // into the expected uint128 result.
        unchecked {
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            return min(result, a / result);
        }
    }

    /**
     * @notice Calculates sqrt(a), following the selected rounding direction.
     */
    function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = sqrt(a);
            return result + (rounding == Rounding.Up && result * result < a ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 2, rounded down, of a positive value.
     * Returns 0 if given 0.
     */
    function log2(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >> 128 > 0) {
                value >>= 128;
                result += 128;
            }
            if (value >> 64 > 0) {
                value >>= 64;
                result += 64;
            }
            if (value >> 32 > 0) {
                value >>= 32;
                result += 32;
            }
            if (value >> 16 > 0) {
                value >>= 16;
                result += 16;
            }
            if (value >> 8 > 0) {
                value >>= 8;
                result += 8;
            }
            if (value >> 4 > 0) {
                value >>= 4;
                result += 4;
            }
            if (value >> 2 > 0) {
                value >>= 2;
                result += 2;
            }
            if (value >> 1 > 0) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 2, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log2(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log2(value);
            return result + (rounding == Rounding.Up && 1 << result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 10, rounded down, of a positive value.
     * Returns 0 if given 0.
     */
    function log10(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >= 10 ** 64) {
                value /= 10 ** 64;
                result += 64;
            }
            if (value >= 10 ** 32) {
                value /= 10 ** 32;
                result += 32;
            }
            if (value >= 10 ** 16) {
                value /= 10 ** 16;
                result += 16;
            }
            if (value >= 10 ** 8) {
                value /= 10 ** 8;
                result += 8;
            }
            if (value >= 10 ** 4) {
                value /= 10 ** 4;
                result += 4;
            }
            if (value >= 10 ** 2) {
                value /= 10 ** 2;
                result += 2;
            }
            if (value >= 10 ** 1) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 10, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log10(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log10(value);
            return result + (rounding == Rounding.Up && 10 ** result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 256, rounded down, of a positive value.
     * Returns 0 if given 0.
     *
     * Adding one to the result gives the number of pairs of hex symbols needed to represent `value` as a hex string.
     */
    function log256(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >> 128 > 0) {
                value >>= 128;
                result += 16;
            }
            if (value >> 64 > 0) {
                value >>= 64;
                result += 8;
            }
            if (value >> 32 > 0) {
                value >>= 32;
                result += 4;
            }
            if (value >> 16 > 0) {
                value >>= 16;
                result += 2;
            }
            if (value >> 8 > 0) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 256, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log256(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log256(value);
            return result + (rounding == Rounding.Up && 1 << (result << 3) < value ? 1 : 0);
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (access/Ownable.sol)

pragma solidity ^0.8.0;

import "../utils/Context.sol";

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

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

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

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

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby disabling any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/// @title Revert reason forwarder.
library RevertReasonForwarder {
    /// @dev Forwards latest externall call revert.
    function reRevert() internal pure {
        // bubble up revert reason from latest external call
        assembly ("memory-safe") { // solhint-disable-line no-inline-assembly
            let ptr := mload(0x40)
            returndatacopy(ptr, 0, returndatasize())
            revert(ptr, returndatasize())
        }
    }
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/extensions/draft-IERC20Permit.sol";
import "../interfaces/IDaiLikePermit.sol";
import "../interfaces/IPermit2.sol";
import "../interfaces/IWETH.sol";
import "../libraries/RevertReasonForwarder.sol";

/**
 * @title Implements efficient safe methods for ERC20 interface.
 * @notice Compared to the standard ERC20, this implementation offers several enhancements:
 * 1. more gas-efficient, providing significant savings in transaction costs.
 * 2. support for different permit implementations
 * 3. forceApprove functionality
 * 4. support for WETH deposit and withdraw
 */
library SafeERC20 {
    error SafeTransferFailed();
    error SafeTransferFromFailed();
    error ForceApproveFailed();
    error SafeIncreaseAllowanceFailed();
    error SafeDecreaseAllowanceFailed();
    error SafePermitBadLength();
    error Permit2TransferAmountTooHigh();

    // Uniswap Permit2 address
    address private constant _PERMIT2 = 0x000000000022D473030F116dDEE9F6B43aC78BA3;
    bytes4 private constant _PERMIT_LENGTH_ERROR = 0x68275857;  // SafePermitBadLength.selector
    uint256 private constant _RAW_CALL_GAS_LIMIT = 5000;

    /**
     * @notice Fetches the balance of a specific ERC20 token held by an account.
     * Consumes less gas then regular `ERC20.balanceOf`.
     * @param token The IERC20 token contract for which the balance will be fetched.
     * @param account The address of the account whose token balance will be fetched.
     * @return tokenBalance The balance of the specified ERC20 token held by the account.
     */
    function safeBalanceOf(
        IERC20 token,
        address account
    ) internal view returns(uint256 tokenBalance) {
        bytes4 selector = IERC20.balanceOf.selector;
        assembly ("memory-safe") { // solhint-disable-line no-inline-assembly
            mstore(0x00, selector)
            mstore(0x04, account)
            let success := staticcall(gas(), token, 0x00, 0x24, 0x00, 0x20)
            tokenBalance := mload(0)

            if or(iszero(success), lt(returndatasize(), 0x20)) {
                let ptr := mload(0x40)
                returndatacopy(ptr, 0, returndatasize())
                revert(ptr, returndatasize())
            }
        }
    }

    /**
     * @notice Attempts to safely transfer tokens from one address to another.
     * @dev If permit2 is true, uses the Permit2 standard; otherwise uses the standard ERC20 transferFrom. 
     * Either requires `true` in return data, or requires target to be smart-contract and empty return data.
     * @param token The IERC20 token contract from which the tokens will be transferred.
     * @param from The address from which the tokens will be transferred.
     * @param to The address to which the tokens will be transferred.
     * @param amount The amount of tokens to transfer.
     * @param permit2 If true, uses the Permit2 standard for the transfer; otherwise uses the standard ERC20 transferFrom.
     */
    function safeTransferFromUniversal(
        IERC20 token,
        address from,
        address to,
        uint256 amount,
        bool permit2
    ) internal {
        if (permit2) {
            safeTransferFromPermit2(token, from, to, amount);
        } else {
            safeTransferFrom(token, from, to, amount);
        }
    }

    /**
     * @notice Attempts to safely transfer tokens from one address to another using the ERC20 standard.
     * @dev Either requires `true` in return data, or requires target to be smart-contract and empty return data.
     * @param token The IERC20 token contract from which the tokens will be transferred.
     * @param from The address from which the tokens will be transferred.
     * @param to The address to which the tokens will be transferred.
     * @param amount The amount of tokens to transfer.
     */
    function safeTransferFrom(
        IERC20 token,
        address from,
        address to,
        uint256 amount
    ) internal {
        bytes4 selector = token.transferFrom.selector;
        bool success;
        assembly ("memory-safe") { // solhint-disable-line no-inline-assembly
            let data := mload(0x40)

            mstore(data, selector)
            mstore(add(data, 0x04), from)
            mstore(add(data, 0x24), to)
            mstore(add(data, 0x44), amount)
            success := call(gas(), token, 0, data, 100, 0x0, 0x20)
            if success {
                switch returndatasize()
                case 0 {
                    success := gt(extcodesize(token), 0)
                }
                default {
                    success := and(gt(returndatasize(), 31), eq(mload(0), 1))
                }
            }
        }
        if (!success) revert SafeTransferFromFailed();
    }

    /**
     * @notice Attempts to safely transfer tokens from one address to another using the Permit2 standard.
     * @dev Either requires `true` in return data, or requires target to be smart-contract and empty return data.
     * @param token The IERC20 token contract from which the tokens will be transferred.
     * @param from The address from which the tokens will be transferred.
     * @param to The address to which the tokens will be transferred.
     * @param amount The amount of tokens to transfer.
     */
    function safeTransferFromPermit2(
        IERC20 token,
        address from,
        address to,
        uint256 amount
    ) internal {
        if (amount > type(uint160).max) revert Permit2TransferAmountTooHigh();
        bytes4 selector = IPermit2.transferFrom.selector;
        bool success;
        assembly ("memory-safe") { // solhint-disable-line no-inline-assembly
            let data := mload(0x40)

            mstore(data, selector)
            mstore(add(data, 0x04), from)
            mstore(add(data, 0x24), to)
            mstore(add(data, 0x44), amount)
            mstore(add(data, 0x64), token)
            success := call(gas(), _PERMIT2, 0, data, 0x84, 0x0, 0x0)
            if success {
                success := gt(extcodesize(_PERMIT2), 0)
            }
        }
        if (!success) revert SafeTransferFromFailed();
    }

    /**
     * @notice Attempts to safely transfer tokens to another address.
     * @dev Either requires `true` in return data, or requires target to be smart-contract and empty return data.
     * @param token The IERC20 token contract from which the tokens will be transferred.
     * @param to The address to which the tokens will be transferred.
     * @param value The amount of tokens to transfer.
     */
    function safeTransfer(
        IERC20 token,
        address to,
        uint256 value
    ) internal {
        if (!_makeCall(token, token.transfer.selector, to, value)) {
            revert SafeTransferFailed();
        }
    }

    /**
     * @notice Attempts to approve a spender to spend a certain amount of tokens.
     * @dev If `approve(from, to, amount)` fails, it tries to set the allowance to zero, and retries the `approve` call.
     * @param token The IERC20 token contract on which the call will be made.
     * @param spender The address which will spend the funds.
     * @param value The amount of tokens to be spent.
     */
    function forceApprove(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        if (!_makeCall(token, token.approve.selector, spender, value)) {
            if (
                !_makeCall(token, token.approve.selector, spender, 0) ||
                !_makeCall(token, token.approve.selector, spender, value)
            ) {
                revert ForceApproveFailed();
            }
        }
    }

    /**
     * @notice Safely increases the allowance of a spender.
     * @dev Increases with safe math check. Checks if the increased allowance will overflow, if yes, then it reverts the transaction.
     * Then uses `forceApprove` to increase the allowance.
     * @param token The IERC20 token contract on which the call will be made.
     * @param spender The address which will spend the funds.
     * @param value The amount of tokens to increase the allowance by.
     */
    function safeIncreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 allowance = token.allowance(address(this), spender);
        if (value > type(uint256).max - allowance) revert SafeIncreaseAllowanceFailed();
        forceApprove(token, spender, allowance + value);
    }

    /**
     * @notice Safely decreases the allowance of a spender.
     * @dev Decreases with safe math check. Checks if the decreased allowance will underflow, if yes, then it reverts the transaction.
     * Then uses `forceApprove` to increase the allowance.
     * @param token The IERC20 token contract on which the call will be made.
     * @param spender The address which will spend the funds.
     * @param value The amount of tokens to decrease the allowance by.
     */
    function safeDecreaseAllowance(
        IERC20 token,
        address spender,
        uint256 value
    ) internal {
        uint256 allowance = token.allowance(address(this), spender);
        if (value > allowance) revert SafeDecreaseAllowanceFailed();
        forceApprove(token, spender, allowance - value);
    }

    /**
     * @notice Attempts to execute the `permit` function on the provided token with the sender and contract as parameters.
     * Permit type is determined automatically based on permit calldata (IERC20Permit, IDaiLikePermit, and IPermit2).
     * @dev Wraps `tryPermit` function and forwards revert reason if permit fails.
     * @param token The IERC20 token to execute the permit function on.
     * @param permit The permit data to be used in the function call.
     */
    function safePermit(IERC20 token, bytes calldata permit) internal {
        if (!tryPermit(token, msg.sender, address(this), permit)) RevertReasonForwarder.reRevert();
    }

    /**
     * @notice Attempts to execute the `permit` function on the provided token with custom owner and spender parameters. 
     * Permit type is determined automatically based on permit calldata (IERC20Permit, IDaiLikePermit, and IPermit2).
     * @dev Wraps `tryPermit` function and forwards revert reason if permit fails.
     * @param token The IERC20 token to execute the permit function on.
     * @param owner The owner of the tokens for which the permit is made.
     * @param spender The spender allowed to spend the tokens by the permit.
     * @param permit The permit data to be used in the function call.
     */
    function safePermit(IERC20 token, address owner, address spender, bytes calldata permit) internal {
        if (!tryPermit(token, owner, spender, permit)) RevertReasonForwarder.reRevert();
    }

    /**
     * @notice Attempts to execute the `permit` function on the provided token with the sender and contract as parameters.
     * @dev Invokes `tryPermit` with sender as owner and contract as spender.
     * @param token The IERC20 token to execute the permit function on.
     * @param permit The permit data to be used in the function call.
     * @return success Returns true if the permit function was successfully executed, false otherwise.
     */
    function tryPermit(IERC20 token, bytes calldata permit) internal returns(bool success) {
        return tryPermit(token, msg.sender, address(this), permit);
    }

    /**
     * @notice The function attempts to call the permit function on a given ERC20 token.
     * @dev The function is designed to support a variety of permit functions, namely: IERC20Permit, IDaiLikePermit, and IPermit2.
     * It accommodates both Compact and Full formats of these permit types.
     * Please note, it is expected that the `expiration` parameter for the compact Permit2 and the `deadline` parameter 
     * for the compact Permit are to be incremented by one before invoking this function. This approach is motivated by
     * gas efficiency considerations; as the unlimited expiration period is likely to be the most common scenario, and 
     * zeros are cheaper to pass in terms of gas cost. Thus, callers should increment the expiration or deadline by one
     * before invocation for optimized performance.
     * @param token The address of the ERC20 token on which to call the permit function.
     * @param owner The owner of the tokens. This address should have signed the off-chain permit.
     * @param spender The address which will be approved for transfer of tokens.
     * @param permit The off-chain permit data, containing different fields depending on the type of permit function.
     * @return success A boolean indicating whether the permit call was successful.
     */
    function tryPermit(IERC20 token, address owner, address spender, bytes calldata permit) internal returns(bool success) {
        // load function selectors for different permit standards
        bytes4 permitSelector = IERC20Permit.permit.selector;
        bytes4 daiPermitSelector = IDaiLikePermit.permit.selector;
        bytes4 permit2Selector = IPermit2.permit.selector;
        assembly ("memory-safe") { // solhint-disable-line no-inline-assembly
            let ptr := mload(0x40)

            // Switch case for different permit lengths, indicating different permit standards
            switch permit.length
            // Compact IERC20Permit
            case 100 {
                mstore(ptr, permitSelector)     // store selector
                mstore(add(ptr, 0x04), owner)   // store owner
                mstore(add(ptr, 0x24), spender) // store spender

                // Compact IERC20Permit.permit(uint256 value, uint32 deadline, uint256 r, uint256 vs)
                {  // stack too deep
                    let deadline := shr(224, calldataload(add(permit.offset, 0x20))) // loads permit.offset 0x20..0x23
                    let vs := calldataload(add(permit.offset, 0x44))                 // loads permit.offset 0x44..0x63

                    calldatacopy(add(ptr, 0x44), permit.offset, 0x20)            // store value     = copy permit.offset 0x00..0x19
                    mstore(add(ptr, 0x64), sub(deadline, 1))                     // store deadline  = deadline - 1
                    mstore(add(ptr, 0x84), add(27, shr(255, vs)))                // store v         = most significant bit of vs + 27 (27 or 28)
                    calldatacopy(add(ptr, 0xa4), add(permit.offset, 0x24), 0x20) // store r         = copy permit.offset 0x24..0x43
                    mstore(add(ptr, 0xc4), shr(1, shl(1, vs)))                   // store s         = vs without most significant bit
                }
                // IERC20Permit.permit(address owner, address spender, uint256 value, uint256 deadline, uint8 v, bytes32 r, bytes32 s)
                success := call(gas(), token, 0, ptr, 0xe4, 0, 0)
            }
            // Compact IDaiLikePermit
            case 72 {
                mstore(ptr, daiPermitSelector)  // store selector
                mstore(add(ptr, 0x04), owner)   // store owner
                mstore(add(ptr, 0x24), spender) // store spender

                // Compact IDaiLikePermit.permit(uint32 nonce, uint32 expiry, uint256 r, uint256 vs)
                {  // stack too deep
                    let expiry := shr(224, calldataload(add(permit.offset, 0x04))) // loads permit.offset 0x04..0x07
                    let vs := calldataload(add(permit.offset, 0x28))               // loads permit.offset 0x28..0x47

                    mstore(add(ptr, 0x44), shr(224, calldataload(permit.offset))) // store nonce   = copy permit.offset 0x00..0x03
                    mstore(add(ptr, 0x64), sub(expiry, 1))                        // store expiry  = expiry - 1
                    mstore(add(ptr, 0x84), true)                                  // store allowed = true
                    mstore(add(ptr, 0xa4), add(27, shr(255, vs)))                 // store v       = most significant bit of vs + 27 (27 or 28)
                    calldatacopy(add(ptr, 0xc4), add(permit.offset, 0x08), 0x20)  // store r       = copy permit.offset 0x08..0x27
                    mstore(add(ptr, 0xe4), shr(1, shl(1, vs)))                    // store s       = vs without most significant bit
                }
                // IDaiLikePermit.permit(address holder, address spender, uint256 nonce, uint256 expiry, bool allowed, uint8 v, bytes32 r, bytes32 s)
                success := call(gas(), token, 0, ptr, 0x104, 0, 0)
            }
            // IERC20Permit
            case 224 {
                mstore(ptr, permitSelector)
                calldatacopy(add(ptr, 0x04), permit.offset, permit.length) // copy permit calldata
                // IERC20Permit.permit(address owner, address spender, uint256 value, uint256 deadline, uint8 v, bytes32 r, bytes32 s)
                success := call(gas(), token, 0, ptr, 0xe4, 0, 0)
            }
            // IDaiLikePermit
            case 256 {
                mstore(ptr, daiPermitSelector)
                calldatacopy(add(ptr, 0x04), permit.offset, permit.length) // copy permit calldata
                // IDaiLikePermit.permit(address holder, address spender, uint256 nonce, uint256 expiry, bool allowed, uint8 v, bytes32 r, bytes32 s)
                success := call(gas(), token, 0, ptr, 0x104, 0, 0)
            }
            // Compact IPermit2
            case 96 {
                // Compact IPermit2.permit(uint160 amount, uint32 expiration, uint32 nonce, uint32 sigDeadline, uint256 r, uint256 vs)
                mstore(ptr, permit2Selector)  // store selector
                mstore(add(ptr, 0x04), owner) // store owner
                mstore(add(ptr, 0x24), token) // store token

                calldatacopy(add(ptr, 0x50), permit.offset, 0x14)             // store amount = copy permit.offset 0x00..0x13
                // and(0xffffffffffff, ...) - conversion to uint48 
                mstore(add(ptr, 0x64), and(0xffffffffffff, sub(shr(224, calldataload(add(permit.offset, 0x14))), 1))) // store expiration = ((permit.offset 0x14..0x17 - 1) & 0xffffffffffff)
                mstore(add(ptr, 0x84), shr(224, calldataload(add(permit.offset, 0x18)))) // store nonce = copy permit.offset 0x18..0x1b
                mstore(add(ptr, 0xa4), spender)                               // store spender
                // and(0xffffffffffff, ...) - conversion to uint48
                mstore(add(ptr, 0xc4), and(0xffffffffffff, sub(shr(224, calldataload(add(permit.offset, 0x1c))), 1))) // store sigDeadline = ((permit.offset 0x1c..0x1f - 1) & 0xffffffffffff)
                mstore(add(ptr, 0xe4), 0x100)                                 // store offset = 256
                mstore(add(ptr, 0x104), 0x40)                                 // store length = 64
                calldatacopy(add(ptr, 0x124), add(permit.offset, 0x20), 0x20) // store r      = copy permit.offset 0x20..0x3f
                calldatacopy(add(ptr, 0x144), add(permit.offset, 0x40), 0x20) // store vs     = copy permit.offset 0x40..0x5f
                // IPermit2.permit(address owner, PermitSingle calldata permitSingle, bytes calldata signature)
                success := call(gas(), _PERMIT2, 0, ptr, 0x164, 0, 0)
            }
            // IPermit2
            case 352 {
                mstore(ptr, permit2Selector)
                calldatacopy(add(ptr, 0x04), permit.offset, permit.length) // copy permit calldata
                // IPermit2.permit(address owner, PermitSingle calldata permitSingle, bytes calldata signature)
                success := call(gas(), _PERMIT2, 0, ptr, 0x164, 0, 0)
            }
            // Unknown
            default {
                mstore(ptr, _PERMIT_LENGTH_ERROR)
                revert(ptr, 4)
            }
        }
    }

    /**
     * @dev Executes a low level call to a token contract, making it resistant to reversion and erroneous boolean returns.
     * @param token The IERC20 token contract on which the call will be made.
     * @param selector The function signature that is to be called on the token contract.
     * @param to The address to which the token amount will be transferred.
     * @param amount The token amount to be transferred.
     * @return success A boolean indicating if the call was successful. Returns 'true' on success and 'false' on failure. 
     * In case of success but no returned data, validates that the contract code exists.
     * In case of returned data, ensures that it's a boolean `true`.
     */
    function _makeCall(
        IERC20 token,
        bytes4 selector,
        address to,
        uint256 amount
    ) private returns (bool success) {
        assembly ("memory-safe") { // solhint-disable-line no-inline-assembly
            let data := mload(0x40)

            mstore(data, selector)
            mstore(add(data, 0x04), to)
            mstore(add(data, 0x24), amount)
            success := call(gas(), token, 0, data, 0x44, 0x0, 0x20)
            if success {
                switch returndatasize()
                case 0 {
                    success := gt(extcodesize(token), 0)
                }
                default {
                    success := and(gt(returndatasize(), 31), eq(mload(0), 1))
                }
            }
        }
    }

    /**
     * @notice Safely deposits a specified amount of Ether into the IWETH contract. Consumes less gas then regular `IWETH.deposit`.
     * @param weth The IWETH token contract.
     * @param amount The amount of Ether to deposit into the IWETH contract.
     */
    function safeDeposit(IWETH weth, uint256 amount) internal {
        if (amount > 0) {
            bytes4 selector = IWETH.deposit.selector;
            assembly ("memory-safe") { // solhint-disable-line no-inline-assembly
                mstore(0, selector)
                if iszero(call(gas(), weth, amount, 0, 4, 0, 0)) {
                    returndatacopy(0, 0, returndatasize())
                    revert(0, returndatasize())
                }
            }
        }
    }

    /**
     * @notice Safely withdraws a specified amount of wrapped Ether from the IWETH contract. Consumes less gas then regular `IWETH.withdraw`.
     * @dev Uses inline assembly to interact with the IWETH contract.
     * @param weth The IWETH token contract.
     * @param amount The amount of wrapped Ether to withdraw from the IWETH contract.
     */
    function safeWithdraw(IWETH weth, uint256 amount) internal {
        bytes4 selector = IWETH.withdraw.selector;
        assembly ("memory-safe") {  // solhint-disable-line no-inline-assembly
            mstore(0, selector)
            mstore(4, amount)
            if iszero(call(gas(), weth, 0, 0, 0x24, 0, 0)) {
                let ptr := mload(0x40)
                returndatacopy(ptr, 0, returndatasize())
                revert(ptr, returndatasize())
            }
        }
    }

    /**
     * @notice Safely withdraws a specified amount of wrapped Ether from the IWETH contract to a specified recipient.
     * Consumes less gas then regular `IWETH.withdraw`.
     * @param weth The IWETH token contract.
     * @param amount The amount of wrapped Ether to withdraw from the IWETH contract.
     * @param to The recipient of the withdrawn Ether.
     */
    function safeWithdrawTo(IWETH weth, uint256 amount, address to) internal {
        safeWithdraw(weth, amount);
        if (to != address(this)) {
            assembly ("memory-safe") {  // solhint-disable-line no-inline-assembly
                if iszero(call(_RAW_CALL_GAS_LIMIT, to, amount, 0, 0, 0, 0)) {
                    let ptr := mload(0x40)
                    returndatacopy(ptr, 0, returndatasize())
                    revert(ptr, returndatasize())
                }
            }
        }
    }
}

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import { FarmAccounting } from "./FarmAccounting.sol";

library UserAccounting {
    struct Info {
        uint40 checkpoint;
        uint216 farmedPerTokenStored;
        mapping(address => int256) corrections;
    }

    function farmedPerToken(
        Info storage info,
        bytes32 context,
        function(bytes32) internal view returns(uint256) lazyGetSupply,
        function(bytes32, uint256) internal view returns(uint256) lazyGetFarmed
    ) internal view returns(uint256) {
        (uint256 checkpoint, uint256 fpt) = (info.checkpoint, info.farmedPerTokenStored);
        if (block.timestamp != checkpoint) {
            uint256 supply = lazyGetSupply(context);
            if (supply > 0) {
                // fpt increases by 168 bit / supply
                unchecked { fpt += lazyGetFarmed(context, checkpoint) / supply; }
            }
        }
        return fpt;
    }

    function farmed(Info storage info, address account, uint256 balance, uint256 fpt) internal view returns(uint256) {
        // balance * fpt is less than 168 bit
        return uint256(int256(balance * fpt) - info.corrections[account]) / FarmAccounting._SCALE;
    }

    function eraseFarmed(Info storage info, address account, uint256 balance, uint256 fpt) internal {
        // balance * fpt is less than 168 bit
        info.corrections[account] = int256(balance * fpt);
    }

    function updateFarmedPerToken(Info storage info, uint256 fpt) internal {
        (info.checkpoint, info.farmedPerTokenStored) = (uint40(block.timestamp), uint216(fpt));
    }

    function updateBalances(Info storage info, address from, address to, uint256 amount, uint256 fpt) internal {
        bool fromZero = (from == address(0));
        bool toZero = (to == address(0));
        if (amount > 0 && from != to) {
            if (fromZero || toZero) {
                updateFarmedPerToken(info, fpt);
            }

            // fpt is less than 168 bit, so amount should be less 98 bit
            int256 diff = int256(amount * fpt);
            if (!fromZero) {
                info.corrections[from] -= diff;
            }
            if (!toZero) {
                info.corrections[to] += diff;
            }
        }
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.9.0) (token/ERC20/extensions/draft-IERC20Permit.sol)

pragma solidity ^0.8.0;

// EIP-2612 is Final as of 2022-11-01. This file is deprecated.

import "./IERC20Permit.sol";

{
  "compilationTarget": {
    "contracts/FarmingPool.sol": "FarmingPool"
  },
  "evmVersion": "london",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs"
  },
  "optimizer": {
    "enabled": true,
    "runs": 1000
  },
  "remappings": [
    ":@1inch/=node_modules/@1inch/",
    ":@chainlink/=node_modules/@chainlink/",
    ":@eth-optimism/=node_modules/@eth-optimism/",
    ":@gearbox-protocol/=node_modules/@gearbox-protocol/",
    ":@openzeppelin/=node_modules/@openzeppelin/",
    ":@redstone-finance/=node_modules/@redstone-finance/",
    ":ds-test/=lib/forge-std/lib/ds-test/src/",
    ":eth-gas-reporter/=node_modules/eth-gas-reporter/",
    ":forge-std/=lib/forge-std/src/"
  ],
  "viaIR": true
}