// SPDX-License-Identifier: MIT
pragma solidity >=0.6.11 <0.9.0;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        // solhint-disable-next-line no-inline-assembly
        assembly { size := extcodesize(account) }
        return size > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (bool success, ) = recipient.call{ value: amount }("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

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

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

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

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

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

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

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

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

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

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

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

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

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

// SPDX-License-Identifier: MIT
pragma solidity >=0.6.11;

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

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

// SPDX-License-Identifier: MIT
pragma solidity >=0.6.11;

import "../Common/Context.sol";
import "./IERC20.sol";
import "../Math/SafeMath.sol";
import "../Utils/Address.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 {ERC20Mintable}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * We have followed general OpenZeppelin guidelines: functions revert instead
 * of 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 {
    using SafeMath for uint256;

    mapping (address => uint256) private _balances;

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

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;
    uint8 private _decimals;
    
    /**
     * @dev Sets the values for {name} and {symbol}, initializes {decimals} with
     * a default value of 18.
     *
     * To select a different value for {decimals}, use {_setupDecimals}.
     *
     * All three of these values are immutable: they can only be set once during
     * construction.
     */
    constructor (string memory __name, string memory __symbol) public {
        _name = __name;
        _symbol = __symbol;
        _decimals = 18;
    }

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

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view 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 value {ERC20} uses, unless {_setupDecimals} is
     * called.
     *
     * 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 returns (uint8) {
        return _decimals;
    }

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

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

    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `recipient` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address recipient, uint256 amount) public virtual override returns (bool) {
        _transfer(_msgSender(), recipient, 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}.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.approve(address spender, uint256 amount)
     */
    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        _approve(_msgSender(), 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};
     *
     * Requirements:
     * - `sender` and `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     * - the caller must have allowance for `sender`'s tokens of at least
     * `amount`.
     */
    function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(sender, _msgSender(), _allowances[sender][_msgSender()].sub(amount, "ERC20: transfer amount exceeds allowance"));
        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) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].add(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) {
        _approve(_msgSender(), spender, _allowances[_msgSender()][spender].sub(subtractedValue, "ERC20: decreased allowance below zero"));
        return true;
    }

    /**
     * @dev Moves tokens `amount` from `sender` to `recipient`.
     *
     * This is 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:
     *
     * - `sender` cannot be the zero address.
     * - `recipient` cannot be the zero address.
     * - `sender` must have a balance of at least `amount`.
     */
    function _transfer(address sender, address recipient, uint256 amount) internal virtual {
        require(sender != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");

        _beforeTokenTransfer(sender, recipient, amount);

        _balances[sender] = _balances[sender].sub(amount, "ERC20: transfer amount exceeds balance");
        _balances[recipient] = _balances[recipient].add(amount);
        emit Transfer(sender, recipient, 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
     *
     * - `to` 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 = _totalSupply.add(amount);
        _balances[account] = _balances[account].add(amount);
        emit Transfer(address(0), account, amount);
    }

    /**
     * @dev Destroys `amount` tokens from the caller.
     *
     * See {ERC20-_burn}.
     */
    function burn(uint256 amount) public virtual {
        _burn(_msgSender(), amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, deducting from the caller's
     * allowance.
     *
     * See {ERC20-_burn} and {ERC20-allowance}.
     *
     * Requirements:
     *
     * - the caller must have allowance for `accounts`'s tokens of at least
     * `amount`.
     */
    function burnFrom(address account, uint256 amount) public virtual {
        uint256 decreasedAllowance = allowance(account, _msgSender()).sub(amount, "ERC20: burn amount exceeds allowance");

        _approve(account, _msgSender(), decreasedAllowance);
        _burn(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);

        _balances[account] = _balances[account].sub(amount, "ERC20: burn amount exceeds balance");
        _totalSupply = _totalSupply.sub(amount);
        emit Transfer(account, address(0), amount);
    }

    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner`s tokens.
     *
     * This is 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 Destroys `amount` tokens from `account`.`amount` is then deducted
     * from the caller's allowance.
     *
     * See {_burn} and {_approve}.
     */
    function _burnFrom(address account, uint256 amount) internal virtual {
        _burn(account, amount);
        _approve(account, _msgSender(), _allowances[account][_msgSender()].sub(amount, "ERC20: burn amount exceeds allowance"));
    }

    /**
     * @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 to 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:using-hooks.adoc[Using Hooks].
     */
    function _beforeTokenTransfer(address from, address to, uint256 amount) internal virtual { }
}

// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.6.11;

// ====================================================================
// |     ______                   _______                             |
// |    / _____________ __  __   / ____(_____  ____ _____  ________   |
// |   / /_  / ___/ __ `| |/_/  / /_  / / __ \/ __ `/ __ \/ ___/ _ \  |
// |  / __/ / /  / /_/ _>  <   / __/ / / / / / /_/ / / / / /__/  __/  |
// | /_/   /_/   \__,_/_/|_|  /_/   /_/_/ /_/\__,_/_/ /_/\___/\___/   |
// |                                                                  |
// ====================================================================
// ================== FraxGaugeFXSRewardsDistributor ==================
// ====================================================================
// Looks at the gauge controller contract and pushes out FXS rewards once
// a week to the gauges (farms)

// Frax Finance: https://github.com/FraxFinance

// Primary Author(s)
// Travis Moore: https://github.com/FortisFortuna

// Reviewer(s) / Contributor(s)
// Jason Huan: https://github.com/jasonhuan
// Sam Kazemian: https://github.com/samkazemian

import "../Math/Math.sol";
import "../Math/SafeMath.sol";
import "../ERC20/ERC20.sol";
import "../ERC20/SafeERC20.sol";
import "./IFraxGaugeController.sol";
import "./FraxMiddlemanGauge.sol";
import '../Uniswap/TransferHelper.sol';
import "../Staking/Owned.sol";

contract FraxGaugeFXSRewardsDistributor is Owned {
    using SafeMath for uint256;
    using SafeERC20 for ERC20;

    /* ========== STATE VARIABLES ========== */

    // Instances and addresses
    address private reward_token_address;
    IFraxGaugeController private gauge_controller;

    // Admin addresses
    address public timelock_address;
    address public curator_address;

    // Constants
    uint256 private constant MULTIPLIER_PRECISION = 1e18;
    uint256 private constant ONE_WEEK = 604800;

    // Gauge controller related
    mapping(address => bool) public gauge_whitelist;
    mapping(address => bool) public is_middleman; // For cross-chain farms, use a middleman contract to push to a bridge
    mapping(address => uint256) public last_time_gauge_paid;

    // Booleans
    bool public distributionsOn;

    /* ========== MODIFIERS ========== */

    modifier onlyByOwnerOrGovernance() {
        require(msg.sender == owner || msg.sender == timelock_address, "Not owner or timelock");
        _;
    }

    modifier onlyByOwnerOrCuratorOrGovernance() {
        require(msg.sender == owner || msg.sender == curator_address || msg.sender == timelock_address, "Not owner, curator, or timelock");
        _;
    }

    modifier isDistributing() {
        require(distributionsOn == true, "Distributions are off");
        _;
    }

    /* ========== CONSTRUCTOR ========== */

    constructor(
        address _owner,
        address _timelock_address,
        address _curator_address,
        address _reward_token_address,
        address _gauge_controller_address
    ) Owned(_owner) {
        curator_address = _curator_address;
        timelock_address = _timelock_address;

        reward_token_address = _reward_token_address;
        gauge_controller = IFraxGaugeController(_gauge_controller_address);

        distributionsOn = true;

    }

    /* ========== VIEWS ========== */

    // Current weekly reward amount
    function currentReward(address gauge_address) public view returns (uint256 reward_amount) {
        uint256 rel_weight = gauge_controller.gauge_relative_weight(gauge_address, block.timestamp);
        uint256 rwd_rate = (gauge_controller.global_emission_rate()).mul(rel_weight).div(1e18);
        reward_amount = rwd_rate.mul(ONE_WEEK);
    }

    /* ========== MUTATIVE FUNCTIONS ========== */

    // Callable by anyone
    function distributeReward(address gauge_address) public isDistributing returns (uint256 weeks_elapsed, uint256 reward_tally) {
        require(gauge_whitelist[gauge_address], "Gauge not whitelisted");
        
        // Calculate the elapsed time in weeks. Truncation desired
        uint256 last_time_paid = last_time_gauge_paid[gauge_address];

        // Edge case for first reward for this gauge
        if (last_time_paid == 0){
            weeks_elapsed = 1;
        }
        else {
            weeks_elapsed = (block.timestamp).sub(last_time_gauge_paid[gauge_address]) / ONE_WEEK;

            // Return early here for 0 weeks instead of throwing, as it could have bad effects in other contracts
            if (weeks_elapsed == 0) {
                return (0, 0);
            }
        }

        // NOTE: This will always use the current global_emission_rate()
        reward_tally = 0;
        for (uint i = 0; i < (weeks_elapsed); i++){ 
            uint256 rel_weight_at_week;
            if (i == 0) {
                // Mutative, for the current week. Makes sure the weight is checkpointed. Also returns the weight.
                rel_weight_at_week = gauge_controller.gauge_relative_weight_write(gauge_address, block.timestamp);
            }
            else {
                // View
                rel_weight_at_week = gauge_controller.gauge_relative_weight(gauge_address, (block.timestamp).sub(ONE_WEEK * i));
            }
            uint256 rwd_rate_at_week = (gauge_controller.global_emission_rate()).mul(rel_weight_at_week).div(1e18);
            reward_tally = reward_tally.add(rwd_rate_at_week.mul(ONE_WEEK));
        }

        // Update the last time paid
        last_time_gauge_paid[gauge_address] = block.timestamp;

        if (is_middleman[gauge_address]){
            // Cross chain: Pay out the rewards to the middleman contract
            // Approve for the middleman first
            ERC20(reward_token_address).approve(gauge_address, reward_tally);

            // Trigger the middleman
            FraxMiddlemanGauge(gauge_address).pullAndBridge(reward_tally);
        }
        else {
            // Mainnet: Pay out the rewards directly to the gauge
            TransferHelper.safeTransfer(reward_token_address, gauge_address, reward_tally);
        }


        emit RewardDistributed(gauge_address, reward_tally);
    }

    /* ========== RESTRICTED FUNCTIONS - Curator / migrator callable ========== */

    // For emergency situations
    function toggleDistributions() external onlyByOwnerOrCuratorOrGovernance {
        distributionsOn = !distributionsOn;

        emit DistributionsToggled(distributionsOn);
    }

    /* ========== RESTRICTED FUNCTIONS - Owner or timelock only ========== */
    
    // Added to support recovering LP Rewards and other mistaken tokens from other systems to be distributed to holders
    function recoverERC20(address tokenAddress, uint256 tokenAmount) external onlyByOwnerOrGovernance {
        // Only the owner address can ever receive the recovery withdrawal
        TransferHelper.safeTransfer(tokenAddress, owner, tokenAmount);
        emit RecoveredERC20(tokenAddress, tokenAmount);
    }

    function setGaugeState(address _gauge_address, bool _is_middleman, bool _is_active) external onlyByOwnerOrGovernance {
        is_middleman[_gauge_address] = _is_middleman;
        gauge_whitelist[_gauge_address] = _is_active;

        emit GaugeStateChanged(_gauge_address, _is_middleman, _is_active);
    }

    function setTimelock(address _new_timelock) external onlyByOwnerOrGovernance {
        timelock_address = _new_timelock;
    }

    function setCurator(address _new_curator_address) external onlyByOwnerOrGovernance {
        curator_address = _new_curator_address;
    }

    function setGaugeController(address _gauge_controller_address) external onlyByOwnerOrGovernance {
        gauge_controller = IFraxGaugeController(_gauge_controller_address);
    }

    /* ========== EVENTS ========== */

    event RewardDistributed(address indexed gauge_address, uint256 reward_amount);
    event RecoveredERC20(address token, uint256 amount);
    event GaugeStateChanged(address gauge_address, bool is_middleman, bool is_active);
    event DistributionsToggled(bool distibutions_state);
}

// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.6.11;

// ====================================================================
// |     ______                   _______                             |
// |    / _____________ __  __   / ____(_____  ____ _____  ________   |
// |   / /_  / ___/ __ `| |/_/  / /_  / / __ \/ __ `/ __ \/ ___/ _ \  |
// |  / __/ / /  / /_/ _>  <   / __/ / / / / / /_/ / / / / /__/  __/  |
// | /_/   /_/   \__,_/_/|_|  /_/   /_/_/ /_/\__,_/_/ /_/\___/\___/   |
// |                                                                  |
// ====================================================================
// ======================== FraxMiddlemanGauge ========================
// ====================================================================
// Looks at the gauge controller contract and pushes out FXS rewards once
// a week to the gauges (farms).
// This contract is what gets added to the gauge as a 'slice'

// Frax Finance: https://github.com/FraxFinance

// Primary Author(s)
// Travis Moore: https://github.com/FortisFortuna

// Reviewer(s) / Contributor(s)
// Jason Huan: https://github.com/jasonhuan
// Sam Kazemian: https://github.com/samkazemian

import "../Math/Math.sol";
import "../Math/SafeMath.sol";
import "../ERC20/ERC20.sol";
import "../ERC20/SafeERC20.sol";
import "./FraxGaugeFXSRewardsDistributor.sol";
import "../Misc_AMOs/polygon/IRootChainManager.sol";
import "../Misc_AMOs/solana/IWormhole.sol";
import '../Uniswap/TransferHelper.sol';
import "../Staking/Owned.sol";

contract FraxMiddlemanGauge is Owned {
    using SafeMath for uint256;
    using SafeERC20 for ERC20;

    /* ========== STATE VARIABLES ========== */

    // Instances and addresses
    address public reward_token_address = 0x3432B6A60D23Ca0dFCa7761B7ab56459D9C964D0; // FXS
    address public rewards_distributor_address;

    // Informational
    string public name;

    // Admin addresses
    address public timelock_address;

    // Gauge-related
    address public bridge_address;
    uint256 public bridge_type;
    address public destination_address_override;
    string public non_evm_destination_address;

    // Tracking
    uint32 public fake_nonce;

    /* ========== MODIFIERS ========== */

    modifier onlyByOwnerOrGovernance() {
        require(msg.sender == owner || msg.sender == timelock_address, "Not owner or timelock");
        _;
    }

    modifier onlyRewardsDistributor() {
        require(msg.sender == rewards_distributor_address, "Not rewards distributor");
        _;
    }

    /* ========== CONSTRUCTOR ========== */

    constructor(
        address _owner,
        address _timelock_address,
        address _rewards_distributor_address,
        address _bridge_address,
        uint256 _bridge_type,
        address _destination_address_override,
        string memory _non_evm_destination_address,
        string memory _name
    ) Owned(_owner) {
        timelock_address = _timelock_address;

        rewards_distributor_address = _rewards_distributor_address;

        bridge_address = _bridge_address;
        bridge_type = _bridge_type;
        destination_address_override = _destination_address_override;
        non_evm_destination_address = _non_evm_destination_address;

        name = _name;

        fake_nonce = 0;
    }

    /* ========== MUTATIVE FUNCTIONS ========== */

    // Callable only by the rewards distributor
    function pullAndBridge(uint256 reward_amount) external onlyRewardsDistributor {
        require(bridge_address != address(0), "Invalid bridge address");

        // Pull in the rewards from the rewards distributor
        TransferHelper.safeTransferFrom(reward_token_address, rewards_distributor_address, address(this), reward_amount);

        address address_to_send_to = address(this);
        if (destination_address_override != address(0)) address_to_send_to = destination_address_override;

        if (bridge_type == 0) {
            // Avalanche [Anyswap]
            TransferHelper.safeTransfer(reward_token_address, address_to_send_to, reward_amount);
        }
        else if (bridge_type == 1) {
            // BSC
            TransferHelper.safeTransfer(reward_token_address, address_to_send_to, reward_amount);
        }
        else if (bridge_type == 2) {
            // Fantom [Anyswap]
            TransferHelper.safeTransfer(reward_token_address, address_to_send_to, reward_amount);
        }
        else if (bridge_type == 3) {
            // Polygon
            // Bridge is 0xA0c68C638235ee32657e8f720a23ceC1bFc77C77
            // Interesting info https://blog.cryption.network/cryption-network-launches-cross-chain-staking-6cf000c25477

            // Approve
            IRootChainManager rootChainMgr = IRootChainManager(bridge_address);
            bytes32 tokenType = rootChainMgr.tokenToType(reward_token_address);
            address predicate = rootChainMgr.typeToPredicate(tokenType);
            ERC20(reward_token_address).approve(predicate, reward_amount);
            
            // DepositFor
            bytes memory depositData = abi.encode(reward_amount);
            rootChainMgr.depositFor(address_to_send_to, reward_token_address, depositData);
        }
        else if (bridge_type == 4) {
            // Solana
            // Wormhole Bridge is 0xf92cD566Ea4864356C5491c177A430C222d7e678

            revert("Not supported yet");

            // // Approve
            // ERC20(reward_token_address).approve(bridge_address, reward_amount);

            // // lockAssets
            // require(non_evm_destination_address != 0, "Invalid destination");
            // // non_evm_destination_address = base58 -> hex
            // // https://www.appdevtools.com/base58-encoder-decoder
            // IWormhole(bridge_address).lockAssets(
            //     reward_token_address,
            //     reward_amount,
            //     non_evm_destination_address,
            //     1,
            //     fake_nonce,
            //     false
            // );
        }

        fake_nonce += 1;
    }

    /* ========== RESTRICTED FUNCTIONS - Owner or timelock only ========== */
    
    // Added to support recovering LP Rewards and other mistaken tokens from other systems to be distributed to holders
    function recoverERC20(address tokenAddress, uint256 tokenAmount) external onlyByOwnerOrGovernance {
        // Only the owner address can ever receive the recovery withdrawal
        TransferHelper.safeTransfer(tokenAddress, owner, tokenAmount);
        emit RecoveredERC20(tokenAddress, tokenAmount);
    }

    function setTimelock(address _new_timelock) external onlyByOwnerOrGovernance {
        timelock_address = _new_timelock;
    }

    function setBridgeInfo(address _bridge_address, uint256 _bridge_type, address _destination_address_override, string memory _non_evm_destination_address) external onlyByOwnerOrGovernance {
        _bridge_address = bridge_address;
        
        // 0: Avalanche
        // 1: BSC
        // 2: Fantom
        // 3: Polygon
        // 4: Solana
        bridge_type = _bridge_type;

        // Overridden cross-chain destination address
        destination_address_override = _destination_address_override;

        // Set bytes32 / non-EVM address on the other chain, if applicable
        non_evm_destination_address = _non_evm_destination_address;
        
        emit BridgeInfoChanged(_bridge_address, _bridge_type, _destination_address_override, _non_evm_destination_address);
    }

    function setRewardsDistributor(address _rewards_distributor_address) external onlyByOwnerOrGovernance {
        rewards_distributor_address = _rewards_distributor_address;
    }

    /* ========== EVENTS ========== */

    event RecoveredERC20(address token, uint256 amount);
    event BridgeInfoChanged(address bridge_address, uint256 bridge_type, address destination_address_override, string non_evm_destination_address);
}

// SPDX-License-Identifier: MIT
pragma solidity >=0.6.11;

import "../Common/Context.sol";
import "../Math/SafeMath.sol";

/**
 * @dev Interface of the ERC20 standard as defined in the EIP. Does not include
 * the optional functions; to access them see {ERC20Detailed}.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

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

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

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

pragma solidity >=0.6.11;

// https://github.com/swervefi/swerve/edit/master/packages/swerve-contracts/interfaces/IGaugeController.sol

interface IFraxGaugeController {
    struct Point {
        uint256 bias;
        uint256 slope;
    }

    struct VotedSlope {
        uint256 slope;
        uint256 power;
        uint256 end;
    }

    // Public variables
    function admin() external view returns (address);
    function future_admin() external view returns (address);
    function token() external view returns (address);
    function voting_escrow() external view returns (address);
    function n_gauge_types() external view returns (int128);
    function n_gauges() external view returns (int128);
    function gauge_type_names(int128) external view returns (string memory);
    function gauges(uint256) external view returns (address);
    function vote_user_slopes(address, address)
        external
        view
        returns (VotedSlope memory);
    function vote_user_power(address) external view returns (uint256);
    function last_user_vote(address, address) external view returns (uint256);
    function points_weight(address, uint256)
        external
        view
        returns (Point memory);
    function time_weight(address) external view returns (uint256);
    function points_sum(int128, uint256) external view returns (Point memory);
    function time_sum(uint256) external view returns (uint256);
    function points_total(uint256) external view returns (uint256);
    function time_total() external view returns (uint256);
    function points_type_weight(int128, uint256)
        external
        view
        returns (uint256);
    function time_type_weight(uint256) external view returns (uint256);

    // Getter functions
    function gauge_types(address) external view returns (int128);
    function gauge_relative_weight(address, uint256)
        external
        view
        returns (uint256);
    function get_gauge_weight(address) external view returns (uint256);
    function get_type_weight(int128) external view returns (uint256);
    function get_total_weight() external view returns (uint256);
    function get_weights_sum_per_type(int128) external view returns (uint256);

    // External functions
    function commit_transfer_ownership(address) external;
    function apply_transfer_ownership() external;
    function add_gauge(
        address,
        int128,
        uint256
    ) external;
    function checkpoint() external;
    function checkpoint_gauge(address) external;
    function global_emission_rate() external view returns (uint256);
    function gauge_relative_weight_write(address, uint256)
        external
        returns (uint256);
    function add_type(string memory, uint256) external;
    function change_type_weight(int128, uint256) external;
    function change_gauge_weight(address, uint256) external;
    function change_global_emission_rate(uint256) external;
    function vote_for_gauge_weights(address, uint256) external;
}

// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.6.11;
pragma experimental ABIEncoderV2;

interface IRootChainManager {
  function depositFor (address user, address rootToken, bytes memory depositData) external;
  function tokenToType (address) external view returns (bytes32);
  function typeToPredicate (bytes32) external view returns (address);

}

// interface GeneratedInterface {
//   function DEFAULT_ADMIN_ROLE (  ) external view returns ( bytes32 );
//   function DEPOSIT (  ) external view returns ( bytes32 );
//   function ERC712_VERSION (  ) external view returns ( string );
//   function ETHER_ADDRESS (  ) external view returns ( address );
//   function MAPPER_ROLE (  ) external view returns ( bytes32 );
//   function MAP_TOKEN (  ) external view returns ( bytes32 );
//   function checkpointManagerAddress (  ) external view returns ( address );
//   function childChainManagerAddress (  ) external view returns ( address );
//   function childToRootToken ( address ) external view returns ( address );
//   function cleanMapToken ( address rootToken, address childToken ) external;
//   function depositEtherFor ( address user ) external;
//   function depositFor ( address user, address rootToken, bytes depositData ) external;
//   function executeMetaTransaction ( address userAddress, bytes functionSignature, bytes32 sigR, bytes32 sigS, uint8 sigV ) external returns ( bytes );
//   function exit ( bytes inputData ) external;
//   function getChainId (  ) external pure returns ( uint256 );
//   function getDomainSeperator (  ) external view returns ( bytes32 );
//   function getNonce ( address user ) external view returns ( uint256 nonce );
//   function getRoleAdmin ( bytes32 role ) external view returns ( bytes32 );
//   function getRoleMember ( bytes32 role, uint256 index ) external view returns ( address );
//   function getRoleMemberCount ( bytes32 role ) external view returns ( uint256 );
//   function grantRole ( bytes32 role, address account ) external;
//   function hasRole ( bytes32 role, address account ) external view returns ( bool );
//   function initialize ( address _owner ) external;
//   function initializeEIP712 (  ) external;
//   function mapToken ( address rootToken, address childToken, bytes32 tokenType ) external;
//   function processedExits ( bytes32 ) external view returns ( bool );
//   function registerPredicate ( bytes32 tokenType, address predicateAddress ) external;
//   function remapToken ( address rootToken, address childToken, bytes32 tokenType ) external;
//   function renounceRole ( bytes32 role, address account ) external;
//   function revokeRole ( bytes32 role, address account ) external;
//   function rootToChildToken ( address ) external view returns ( address );
//   function setCheckpointManager ( address newCheckpointManager ) external;
//   function setChildChainManagerAddress ( address newChildChainManager ) external;
//   function setStateSender ( address newStateSender ) external;
//   function setupContractId (  ) external;
//   function stateSenderAddress (  ) external view returns ( address );
//   function tokenToType ( address ) external view returns ( bytes32 );
//   function typeToPredicate ( bytes32 ) external view returns ( address );
// }

// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.6.11;
pragma experimental ABIEncoderV2;

interface IWormhole {
  function guardian_set_expirity () external view returns (uint32);
  function guardian_set_index () external view returns (uint32);
  function guardian_sets (uint32) external view returns (uint32 expiration_time);
  function isWrappedAsset (address) external view returns (bool);
  function lockAssets (address asset, uint256 amount, bytes32 recipient, uint8 target_chain, uint32 nonce, bool refund_dust) external;
  function lockETH (bytes32 recipient, uint8 target_chain, uint32 nonce) external;
  function wrappedAssetMaster () external view returns (address);
  function wrappedAssets (bytes32) external view returns (address);
}

// SPDX-License-Identifier: MIT
pragma solidity >=0.6.11;

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

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

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

    // babylonian method (https://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Babylonian_method)
    function sqrt(uint y) internal pure returns (uint z) {
        if (y > 3) {
            z = y;
            uint x = y / 2 + 1;
            while (x < z) {
                z = x;
                x = (y / x + x) / 2;
            }
        } else if (y != 0) {
            z = 1;
        }
    }
}

// SPDX-License-Identifier: GPL-2.0-or-later
pragma solidity >=0.6.11;

// https://docs.synthetix.io/contracts/Owned
contract Owned {
    address public owner;
    address public nominatedOwner;

    constructor(address _owner) public {
        require(_owner != address(0), "Owner address cannot be 0");
        owner = _owner;
        emit OwnerChanged(address(0), _owner);
    }

    function nominateNewOwner(address _owner) external onlyOwner {
        nominatedOwner = _owner;
        emit OwnerNominated(_owner);
    }

    function acceptOwnership() external {
        require(msg.sender == nominatedOwner, "You must be nominated before you can accept ownership");
        emit OwnerChanged(owner, nominatedOwner);
        owner = nominatedOwner;
        nominatedOwner = address(0);
    }

    modifier onlyOwner {
        require(msg.sender == owner, "Only the contract owner may perform this action");
        _;
    }

    event OwnerNominated(address newOwner);
    event OwnerChanged(address oldOwner, address newOwner);
}

// SPDX-License-Identifier: MIT
pragma solidity >=0.6.11;

import "./IERC20.sol";
import "../Math/SafeMath.sol";
import "../Utils/Address.sol";

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using SafeMath for uint256;
    using Address for address;

    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(IERC20 token, address spender, uint256 value) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        // solhint-disable-next-line max-line-length
        require((value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).add(value);
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        if (returndata.length > 0) { // Return data is optional
            // solhint-disable-next-line max-line-length
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

// SPDX-License-Identifier: MIT
pragma solidity >=0.6.11;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     *
     * _Available since v2.4.0._
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     *
     * _Available since v2.4.0._
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     *
     * _Available since v2.4.0._
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

// SPDX-License-Identifier: MIT
pragma solidity >=0.6.11;

// helper methods for interacting with ERC20 tokens and sending ETH that do not consistently return true/false
library TransferHelper {
    function safeApprove(address token, address to, uint value) internal {
        // bytes4(keccak256(bytes('approve(address,uint256)')));
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x095ea7b3, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), 'TransferHelper: APPROVE_FAILED');
    }

    function safeTransfer(address token, address to, uint value) internal {
        // bytes4(keccak256(bytes('transfer(address,uint256)')));
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0xa9059cbb, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), 'TransferHelper: TRANSFER_FAILED');
    }

    function safeTransferFrom(address token, address from, address to, uint value) internal {
        // bytes4(keccak256(bytes('transferFrom(address,address,uint256)')));
        (bool success, bytes memory data) = token.call(abi.encodeWithSelector(0x23b872dd, from, to, value));
        require(success && (data.length == 0 || abi.decode(data, (bool))), 'TransferHelper: TRANSFER_FROM_FAILED');
    }

    function safeTransferETH(address to, uint value) internal {
        (bool success,) = to.call{value:value}(new bytes(0));
        require(success, 'TransferHelper: ETH_TRANSFER_FAILED');
    }
}

{
  "compilationTarget": {
    "contracts/Curve/FraxGaugeFXSRewardsDistributor.sol": "FraxGaugeFXSRewardsDistributor"
  },
  "evmVersion": "istanbul",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs",
    "useLiteralContent": true
  },
  "optimizer": {
    "enabled": true,
    "runs": 100000
  },
  "remappings": []
}