// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (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
     * ====
     *
     * [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://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");

        (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-FileCopyrightText: © 2017, 2018, 2019 dbrock, rain, mrchico
// SPDX-FileCopyrightText: © 2023 Dai Foundation <www.daifoundation.org>
// SPDX-License-Identifier: AGPL-3.0-or-later
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.
pragma solidity ^0.8.16;

interface DssVestWithGemLike {
    function valid(uint256 _id) external view returns (bool);

    function usr(uint256 id) external view returns (address);

    function bgn(uint256 id) external view returns (uint256);

    function clf(uint256 id) external view returns (uint256);

    function fin(uint256 id) external view returns (uint256);

    function mgr(uint256 id) external view returns (address);

    function res(uint256 id) external view returns (uint256);

    function tot(uint256 id) external view returns (uint256);

    function rxd(uint256 id) external view returns (uint256);

    function accrued(uint256 id) external view returns (uint256);

    function unpaid(uint256 _id) external view returns (uint256);

    // @dev This function is not part of the DssVest interface, it's only present in the concrete implementations
    // DssVestMintable and DssVestTransferable.
    function gem() external view returns (address);

    function rely(address who) external;

    function deny(address who) external;

    function file(bytes32 what, uint256 data) external;

    function create(
        address _usr,
        uint256 _tot,
        uint256 _bgn,
        uint256 _tau,
        uint256 _eta,
        address _mgr
    ) external returns (uint256 id);

    function restrict(uint256 _id) external;

    function unrestrict(uint256 _id) external;

    function vest(uint256 id) external;

    function vest(uint256 id, uint256 _maxAmt) external;
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (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-FileCopyrightText: © 2019-2021 Synthetix
// SPDX-FileCopyrightText: © 2023 Dai Foundation <www.daifoundation.org>
// SPDX-License-Identifier: MIT AND AGPL-3.0-or-later
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.
pragma solidity ^0.8.16;

import {IERC20} from "openzeppelin-contracts/token/ERC20/utils/SafeERC20.sol";

// https://docs.synthetix.io/contracts/source/interfaces/istakingrewards
interface IStakingRewards {
    // Views

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

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

    function getRewardForDuration() external view returns (uint256);

    function lastTimeRewardApplicable() external view returns (uint256);

    function rewardPerToken() external view returns (uint256);

    function rewardsDistribution() external view returns (address);

    function rewardsToken() external view returns (IERC20);

    function stakingToken() external view returns (IERC20);

    function totalSupply() external view returns (uint256);

    // Mutative

    function exit() external;

    function getReward() external;

    function stake(uint256 amount) external;

    function stake(uint256 amount, uint16 referral) external;

    function withdraw(uint256 amount) external;

    function notifyRewardAmount(uint256 reward) external;

    function setRewardsDistribution(address _rewardsDistribution) external;

    function setRewardsDuration(uint256 _rewardsDuration) external;

    function recoverERC20(address tokenAddress, uint256 tokenAmount) external;
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";
import "../extensions/draft-IERC20Permit.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'
        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));
        }
    }

    function safePermit(
        IERC20Permit token,
        address owner,
        address spender,
        uint256 value,
        uint256 deadline,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal {
        uint256 nonceBefore = token.nonces(owner);
        token.permit(owner, spender, value, deadline, v, r, s);
        uint256 nonceAfter = token.nonces(owner);
        require(nonceAfter == nonceBefore + 1, "SafeERC20: permit did not succeed");
    }

    /**
     * @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
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

// SPDX-FileCopyrightText: © 2023 Dai Foundation <www.daifoundation.org>
// SPDX-License-Identifier: AGPL-3.0-or-later
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.
pragma solidity ^0.8.16;

import {IStakingRewards} from "./synthetix/interfaces/IStakingRewards.sol";
import {DssVestWithGemLike} from "./interfaces/DssVestWithGemLike.sol";
import {IERC20} from "openzeppelin-contracts/token/ERC20/IERC20.sol";

/**
 * @title VestedRewardsDistribution: A permissionless bridge between {DssVest} and {StakingRewards}.
 * @author @amusingaxl
 */
contract VestedRewardsDistribution {
    /// @notice Addresses with owner access on this contract. `wards[usr]`
    mapping(address => uint256) public wards;

    /// @notice DssVest instance for token rewards.
    DssVestWithGemLike public immutable dssVest;
    /// @notice StakingRewards instance to enable farming.
    IStakingRewards public immutable stakingRewards;
    /// @notice Token in which rewards are being paid.
    IERC20 public immutable gem;

    /// @dev Vest IDs are sequential, but they are incremented before usage, meaning `0` is not a valid vest ID.
    uint256 internal constant INVALID_VEST_ID = 0;
    /// @notice The vest ID managed by this contract.
    /// @dev It is initialized to an invalid value to prevent calls before the vest ID being set.
    /// The reason this is not a required constructor parameter is that there is a circular dependency
    /// between this contract and the creation of the vest: the address of this contract must be the vest `usr`.
    uint256 public vestId = INVALID_VEST_ID;
    /// @notice Tracks the last time a distribution was made.
    uint256 public lastDistributedAt;

    /**
     * @dev `usr` was granted owner access.
     * @param usr The user address.
     */
    event Rely(address indexed usr);
    /**
     * @notice `usr` owner access was revoked.
     * @param usr The user address.
     */
    event Deny(address indexed usr);
    /**
     * @notice A contract parameter was updated.
     * @param what The changed parameter name. Currently the supported values are: "vestID"
     * @param data The new value of the parameter.
     */
    event File(bytes32 indexed what, uint256 data);
    /**
     * @notice A distribution of tokens was made.
     * @param amount The total tokens in the current distribution.
     */
    event Distribute(uint256 amount);

    modifier auth() {
        require(wards[msg.sender] == 1, "VestedRewardsDistribution/not-authorized");
        _;
    }

    /**
     * @dev The token `gem` used in DssVest must be the same as `rewardsToken` in StakingRewards.
     * @param _dssVest The DssVest instance as the source of the funds.
     * @param _stakingRewards The farming contract.
     */
    constructor(address _dssVest, address _stakingRewards) {
        address _gem = DssVestWithGemLike(_dssVest).gem();
        require(
            _gem == address(IStakingRewards(_stakingRewards).rewardsToken()),
            "VestedRewardsDistribution/invalid-gem"
        );

        dssVest = DssVestWithGemLike(_dssVest);
        stakingRewards = IStakingRewards(_stakingRewards);
        gem = IERC20(_gem);

        wards[msg.sender] = 1;
        emit Rely(msg.sender);
    }

    // --- Administration ---

    /**
     * @notice Grants `usr` admin access to this contract.
     * @param usr The user address.
     */
    function rely(address usr) external auth {
        wards[usr] = 1;
        emit Rely(usr);
    }

    /**
     * @notice Revokes `usr` admin access from this contract.
     * @param usr The user address.
     */
    function deny(address usr) external auth {
        wards[usr] = 0;
        emit Deny(usr);
    }

    /**
     * @notice Updates a contract parameter.
     * @param what The changed parameter name. `"vestId"
     * @param data The new value of the parameter.
     */
    function file(bytes32 what, uint256 data) external auth {
        if (what == "vestId") {
            _setVestId(data);
        } else {
            revert("VestedRewardsDistribution/file-unrecognized-param");
        }

        emit File(what, data);
    }

    /**
     * @notice Updates the `vestId` managed by this contract.
     * @dev The `_vestId` must be valid, in favor of this contract.
     * @dev Vesting streams whose `clf > bgn` are not supported.
     * @dev Unrestricted vesting streams are not supported.
     * @param _vestId The new vest ID.
     */
    function _setVestId(uint256 _vestId) internal {
        require(dssVest.valid(_vestId), "VestedRewardsDistribution/invalid-vest-id");
        require(dssVest.res(_vestId) == 1, "VestedRewardsDistribution/invalid-vest-res");
        require(dssVest.usr(_vestId) == address(this), "VestedRewardsDistribution/invalid-vest-usr");
        require(dssVest.clf(_vestId) == dssVest.bgn(_vestId), "VestedRewardsDistribution/invalid-vest-cliff");

        vestId = _vestId;
        lastDistributedAt = 0;
    }

    /**
     * @notice Distributes the amount of rewards due since the last distribution.
     * @dev Notice we don't need to wait for the current distribution `periodFinish` to be over in the
     * `RewardsDistribution` contract because it can handle new rewards being sent at any given time.
     * @return amount The amount being distributed.
     */
    function distribute() external returns (uint256 amount) {
        require(vestId != INVALID_VEST_ID, "VestedRewardsDistribution/invalid-vest-id");

        amount = dssVest.unpaid(vestId);
        require(amount > 0, "VestedRewardsDistribution/no-pending-amount");

        lastDistributedAt = block.timestamp;
        dssVest.vest(vestId, amount);

        require(gem.transfer(address(stakingRewards), amount), "VestedRewardsDistribution/transfer-failed");
        stakingRewards.notifyRewardAmount(amount);

        emit Distribute(amount);
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/draft-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);
}

{
  "compilationTarget": {
    "src/VestedRewardsDistribution.sol": "VestedRewardsDistribution"
  },
  "evmVersion": "london",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs"
  },
  "optimizer": {
    "enabled": true,
    "runs": 200
  },
  "remappings": [
    ":ds-test/=lib/forge-std/lib/ds-test/src/",
    ":dss-interfaces/=lib/dss-test/lib/dss-interfaces/src/",
    ":dss-test/=lib/dss-test/src/",
    ":dss-vest/=lib-0_6_x/dss-vest/src/",
    ":forge-std/=lib/forge-std/src/",
    ":openzeppelin-contracts/=lib/openzeppelin-contracts/contracts/",
    ":token-tests/=lib/token-tests/src/"
  ]
}