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pragma solidity ^0.5.16;

import "./XVSVaultStorage.sol";
import "./XVSVaultErrorReporter.sol";

contract XVSVaultProxy is XVSVaultAdminStorage, XVSVaultErrorReporter {

    /**
      * @notice Emitted when pendingXVSVaultImplementation is changed
      */
    event NewPendingImplementation(address oldPendingImplementation, address newPendingImplementation);

    /**
      * @notice Emitted when pendingXVSVaultImplementation is accepted, which means XVS Vault implementation is updated
      */
    event NewImplementation(address oldImplementation, address newImplementation);

    /**
      * @notice Emitted when pendingAdmin is changed
      */
    event NewPendingAdmin(address oldPendingAdmin, address newPendingAdmin);

    /**
      * @notice Emitted when pendingAdmin is accepted, which means admin is updated
      */
    event NewAdmin(address oldAdmin, address newAdmin);

    constructor() public {
        // Set admin to caller
        admin = msg.sender;
    }

    /*** Admin Functions ***/
    function _setPendingImplementation(address newPendingImplementation) public returns (uint) {

        if (msg.sender != admin) {
            return fail(Error.UNAUTHORIZED, FailureInfo.SET_PENDING_IMPLEMENTATION_OWNER_CHECK);
        }

        address oldPendingImplementation = pendingXVSVaultImplementation;

        pendingXVSVaultImplementation = newPendingImplementation;

        emit NewPendingImplementation(oldPendingImplementation, pendingXVSVaultImplementation);

        return uint(Error.NO_ERROR);
    }

    /**
    * @notice Accepts new implementation of XVS Vault. msg.sender must be pendingImplementation
    * @dev Admin function for new implementation to accept it's role as implementation
    * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
    */
    function _acceptImplementation() public returns (uint) {
        // Check caller is pendingImplementation
        if (msg.sender != pendingXVSVaultImplementation) {
            return fail(Error.UNAUTHORIZED, FailureInfo.ACCEPT_PENDING_IMPLEMENTATION_ADDRESS_CHECK);
        }

        // Save current values for inclusion in log
        address oldImplementation = implementation;
        address oldPendingImplementation = pendingXVSVaultImplementation;

        implementation = pendingXVSVaultImplementation;

        pendingXVSVaultImplementation = address(0);

        emit NewImplementation(oldImplementation, implementation);
        emit NewPendingImplementation(oldPendingImplementation, pendingXVSVaultImplementation);

        return uint(Error.NO_ERROR);
    }


    /**
      * @notice Begins transfer of admin rights. The newPendingAdmin must call `_acceptAdmin` to finalize the transfer.
      * @dev Admin function to begin change of admin. The newPendingAdmin must call `_acceptAdmin` to finalize the transfer.
      * @param newPendingAdmin New pending admin.
      * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
      */
    function _setPendingAdmin(address newPendingAdmin) public returns (uint) {
        // Check caller = admin
        if (msg.sender != admin) {
            return fail(Error.UNAUTHORIZED, FailureInfo.SET_PENDING_ADMIN_OWNER_CHECK);
        }

        // Save current value, if any, for inclusion in log
        address oldPendingAdmin = pendingAdmin;

        // Store pendingAdmin with value newPendingAdmin
        pendingAdmin = newPendingAdmin;

        // Emit NewPendingAdmin(oldPendingAdmin, newPendingAdmin)
        emit NewPendingAdmin(oldPendingAdmin, newPendingAdmin);

        return uint(Error.NO_ERROR);
    }

    /**
      * @notice Accepts transfer of admin rights. msg.sender must be pendingAdmin
      * @dev Admin function for pending admin to accept role and update admin
      * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
      */
    function _acceptAdmin() public returns (uint) {
        // Check caller is pendingAdmin
        if (msg.sender != pendingAdmin) {
            return fail(Error.UNAUTHORIZED, FailureInfo.ACCEPT_ADMIN_PENDING_ADMIN_CHECK);
        }

        // Save current values for inclusion in log
        address oldAdmin = admin;
        address oldPendingAdmin = pendingAdmin;

        // Store admin with value pendingAdmin
        admin = pendingAdmin;

        // Clear the pending value
        pendingAdmin = address(0);

        emit NewAdmin(oldAdmin, admin);
        emit NewPendingAdmin(oldPendingAdmin, pendingAdmin);

        return uint(Error.NO_ERROR);
    }

    /**
     * @dev Delegates execution to an implementation contract.
     * It returns to the external caller whatever the implementation returns
     * or forwards reverts.
     */
    function () external payable {
        // delegate all other functions to current implementation
        (bool success, ) = implementation.delegatecall(msg.data);

        assembly {
              let free_mem_ptr := mload(0x40)
              returndatacopy(free_mem_ptr, 0, returndatasize)

              switch success
              case 0 { revert(free_mem_ptr, returndatasize) }
              default { return(free_mem_ptr, returndatasize) }
        }
    }
}

pragma solidity ^0.5.16;
pragma experimental ABIEncoderV2;

import "../Utils/ECDSA.sol";
import "../Utils/SafeBEP20.sol";
import "../Utils/IBEP20.sol";
import "./XVSVaultProxy.sol";
import "./XVSVaultStorage.sol";
import "./XVSVaultErrorReporter.sol";

interface IXVSStore {
    function safeRewardTransfer(address _token, address _to, uint256 _amount) external;
    function setRewardToken(address _tokenAddress, bool status) external;
}

contract XVSVault is XVSVaultStorage, ECDSA {
    using SafeMath for uint256;
    using SafeBEP20 for IBEP20;

    /// @notice Event emitted when deposit
    event Deposit(address indexed user, address indexed rewardToken, uint256 indexed pid, uint256 amount);

    /// @notice Event emitted when execute withrawal
    event ExecutedWithdrawal(address indexed user, address indexed rewardToken, uint256 indexed pid, uint256 amount);

    /// @notice Event emitted when request withrawal
    event ReqestedWithdrawal(address indexed user, address indexed rewardToken, uint256 indexed pid, uint256 amount);

    /// @notice Event emitted when admin changed
    event AdminTransferred(address indexed oldAdmin, address indexed newAdmin);

    /// @notice An event thats emitted when an account changes its delegate
    event DelegateChanged(address indexed delegator, address indexed fromDelegate, address indexed toDelegate);

    /// @notice An event thats emitted when a delegate account's vote balance changes
    event DelegateVotesChanged(address indexed delegate, uint previousBalance, uint newBalance);

    /// @notice An event emitted when the reward store address is updated
    event StoreUpdated(address oldXvs, address oldStore, address newXvs, address newStore);

    /// @notice An event emitted when the withdrawal locking period is updated for a pool
    event WithdrawalLockingPeriodUpdated(
        address indexed rewardToken,
        uint indexed pid,
        uint oldPeriod,
        uint newPeriod
    );

    /// @notice An event emitted when the reward amount per block is modified for a pool
    event RewardAmountUpdated(address indexed rewardToken, uint oldReward, uint newReward);

    /// @notice An event emitted when a new pool is added
    event PoolAdded(
        address indexed rewardToken,
        uint indexed pid,
        address indexed token,
        uint allocPoints,
        uint rewardPerBlock,
        uint lockPeriod
    );

    /// @notice An event emitted when a pool allocation points are updated
    event PoolUpdated(
        address indexed rewardToken,
        uint indexed pid,
        uint oldAllocPoints,
        uint newAllocPoints
    );

    constructor() public {
        admin = msg.sender;
    }

    modifier onlyAdmin() {
        require(msg.sender == admin, "only admin can");
        _;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     */
    modifier nonReentrant() {
        require(_notEntered, "re-entered");
        _notEntered = false;
        _;
        _notEntered = true; // get a gas-refund post-Istanbul
    }

    function poolLength(address rewardToken) external view returns (uint256) {
        return poolInfos[rewardToken].length;
    }

    /**
     * @notice Add a new token pool. Can only be called by the admin.
     * @dev This vault DOES NOT support deflationary tokens — it expects that
     *   the amount of transferred tokens would equal the actually deposited
     *   amount. In practice this means that this vault DOES NOT support USDT
     *   and similar tokens (that do not provide these guarantees).
     */
    function add(
        address _rewardToken,
        uint256 _allocPoint,
        IBEP20 _token,
        uint256 _rewardPerBlock,
        uint256 _lockPeriod
    )
        external
        onlyAdmin
    {
        require(address(xvsStore) != address(0), "Store contract addres is empty");

        massUpdatePools(_rewardToken);

        PoolInfo[] storage poolInfo = poolInfos[_rewardToken];

        uint256 length = poolInfo.length;
        for (uint256 pid = 0; pid < length; ++pid) {
            require(poolInfo[pid].token != _token, "Error pool already added");
        }

        totalAllocPoints[_rewardToken] = totalAllocPoints[_rewardToken].add(_allocPoint);

        rewardTokenAmountsPerBlock[_rewardToken] = _rewardPerBlock;

        poolInfo.push(
            PoolInfo({
                token: _token,
                allocPoint: _allocPoint,
                lastRewardBlock: block.number,
                accRewardPerShare: 0,
                lockPeriod: _lockPeriod
            })
        );

        IXVSStore(xvsStore).setRewardToken(_rewardToken, true);

        emit PoolAdded(
            _rewardToken,
            poolInfo.length - 1,
            address(_token),
            _allocPoint,
            _rewardPerBlock,
            _lockPeriod
        );
    }

    // Update the given pool's reward allocation point. Can only be called by the admin.
    function set(
        address _rewardToken,
        uint256 _pid,
        uint256 _allocPoint
    )
        external
        onlyAdmin
    {
        _ensureValidPool(_rewardToken, _pid);
        massUpdatePools(_rewardToken);

        PoolInfo[] storage poolInfo = poolInfos[_rewardToken];
        totalAllocPoints[_rewardToken] = totalAllocPoints[_rewardToken].sub(poolInfo[_pid].allocPoint).add(
            _allocPoint
        );
        uint256 oldAllocPoints = poolInfo[_pid].allocPoint;
        poolInfo[_pid].allocPoint = _allocPoint;

        emit PoolUpdated(_rewardToken, _pid, oldAllocPoints, _allocPoint);
    }

    // Update the given reward token's amount per block
    function setRewardAmountPerBlock(
        address _rewardToken,
        uint256 _rewardAmount
    )
        external
        onlyAdmin
    {
        massUpdatePools(_rewardToken);
        uint256 oldReward = rewardTokenAmountsPerBlock[_rewardToken];
        rewardTokenAmountsPerBlock[_rewardToken] = _rewardAmount;

        emit RewardAmountUpdated(_rewardToken, oldReward, _rewardAmount);
    }

    // Update the given reward token's amount per block
    function setWithdrawalLockingPeriod(
        address _rewardToken,
        uint256 _pid,
        uint256 _newPeriod
    )
        external
        onlyAdmin
    {
        _ensureValidPool(_rewardToken, _pid);
        require(_newPeriod > 0, "Invalid new locking period");
        PoolInfo storage pool = poolInfos[_rewardToken][_pid];
        uint256 oldPeriod = pool.lockPeriod;
        pool.lockPeriod = _newPeriod;

        emit WithdrawalLockingPeriodUpdated(_rewardToken, _pid, oldPeriod, _newPeriod);
    }

    /**
     * @notice Deposit XVSVault for XVS allocation
     * @param _rewardToken The Reward Token Address
     * @param _pid The Pool Index
     * @param _amount The amount to deposit to vault
     */
    function deposit(address _rewardToken, uint256 _pid, uint256 _amount)
        external
        nonReentrant
    {
        _ensureValidPool(_rewardToken, _pid);
        PoolInfo storage pool = poolInfos[_rewardToken][_pid];
        UserInfo storage user = userInfos[_rewardToken][_pid][msg.sender];
        _updatePool(_rewardToken, _pid);
        if (user.amount > 0) {
            uint256 pending =
                user.amount.mul(pool.accRewardPerShare).div(1e12).sub(
                    user.rewardDebt
                );
            IXVSStore(xvsStore).safeRewardTransfer(_rewardToken, msg.sender, pending);
        }
        pool.token.safeTransferFrom(
            address(msg.sender),
            address(this),
            _amount
        );
        user.amount = user.amount.add(_amount);
        user.rewardDebt = user.amount.mul(pool.accRewardPerShare).div(1e12);

        // Update Delegate Amount
        if (address(pool.token) == address(xvsAddress)) {
            uint256 updatedAmount = user.amount.sub(user.pendingWithdrawals);
            _updateDelegate(address(msg.sender), uint96(updatedAmount));
        }

        emit Deposit(msg.sender, _rewardToken, _pid, _amount);
    }

    /**
     * @notice Pushes withdrawal request to the requests array and updates
     *   the pending withdrawals amount. The requests are always sorted
     *   by unlock time (descending) so that the earliest to execute requests
     *   are always at the end of the array.
     * @param _user The user struct storage pointer
     * @param _requests The user's requests array storage pointer
     * @param _amount The amount being requested
     */
    function pushWithdrawalRequest(
        UserInfo storage _user,
        WithdrawalRequest[] storage _requests,
        uint _amount,
        uint _lockedUntil
    )
        internal
    {
        uint i = _requests.length;
        _requests.push(WithdrawalRequest(0, 0));
        // Keep it sorted so that the first to get unlocked request is always at the end
        for (; i > 0 && _requests[i - 1].lockedUntil <= _lockedUntil; --i) {
            _requests[i] = _requests[i - 1];
        }
        _requests[i] = WithdrawalRequest(_amount, _lockedUntil);
        _user.pendingWithdrawals = _user.pendingWithdrawals.add(_amount);
    }

    /**
     * @notice Pops the requests with unlock time < now from the requests
     *   array and deducts the computed amount from the user's pending
     *   withdrawals counter. Assumes that the requests array is sorted
     *   by unclock time (descending).
     * @dev This function **removes** the eligible requests from the requests
     *   array. If this function is called, the withdrawal should actually
     *   happen (or the transaction should be reverted).
     * @param _user The user struct storage pointer
     * @param _requests The user's requests array storage pointer
     * @return The amount eligible for withdrawal (this amount should be
     *   sent to the user, otherwise the state would be inconsistent).
     */
    function popEligibleWithdrawalRequests(
        UserInfo storage _user,
        WithdrawalRequest[] storage _requests
    )
        internal
        returns (uint withdrawalAmount)
    {
        // Since the requests are sorted by their unlock time, we can just
        // pop them from the array and stop at the first not-yet-eligible one
        for (uint i = _requests.length; i > 0 && isUnlocked(_requests[i - 1]); --i) {
            withdrawalAmount = withdrawalAmount.add(_requests[i - 1].amount);
            _requests.pop();
        }
        _user.pendingWithdrawals = _user.pendingWithdrawals.sub(withdrawalAmount);
        return withdrawalAmount;
    }

    /**
     * @notice Checks if the request is eligible for withdrawal.
     * @param _request The request struct storage pointer
     * @return True if the request is eligible for withdrawal, false otherwise
     */
    function isUnlocked(WithdrawalRequest storage _request) private view returns (bool) {
        return _request.lockedUntil <= block.timestamp;
    }

    /**
     * @notice Execute withdrawal to XVSVault for XVS allocation
     * @param _rewardToken The Reward Token Address
     * @param _pid The Pool Index
     */
    function executeWithdrawal(address _rewardToken, uint256 _pid)
        external
        nonReentrant
    {
        _ensureValidPool(_rewardToken, _pid);
        PoolInfo storage pool = poolInfos[_rewardToken][_pid];
        UserInfo storage user = userInfos[_rewardToken][_pid][msg.sender];
        WithdrawalRequest[] storage requests = withdrawalRequests[_rewardToken][_pid][msg.sender];

        uint256 _amount = popEligibleWithdrawalRequests(user, requests);
        require(_amount > 0, "nothing to withdraw");

        _updatePool(_rewardToken, _pid);
        uint256 pending =
            user.amount.mul(pool.accRewardPerShare).div(1e12).sub(
                user.rewardDebt
            );
        IXVSStore(xvsStore).safeRewardTransfer(_rewardToken, msg.sender, pending);
        user.amount = user.amount.sub(_amount);
        user.rewardDebt = user.amount.mul(pool.accRewardPerShare).div(1e12);
        pool.token.safeTransfer(address(msg.sender), _amount);

        emit ExecutedWithdrawal(msg.sender, _rewardToken, _pid, _amount);
    }

    /**
     * @notice Request withdrawal to XVSVault for XVS allocation
     * @param _rewardToken The Reward Token Address
     * @param _pid The Pool Index
     * @param _amount The amount to withdraw to vault
     */
    function requestWithdrawal(address _rewardToken, uint256 _pid, uint256 _amount)
        external
        nonReentrant
    {
        _ensureValidPool(_rewardToken, _pid);
        require(_amount > 0, "requested amount cannot be zero");
        UserInfo storage user = userInfos[_rewardToken][_pid][msg.sender];
        require(user.amount >= user.pendingWithdrawals.add(_amount), "requested amount is invalid");

        PoolInfo storage pool = poolInfos[_rewardToken][_pid];
        WithdrawalRequest[] storage requests = withdrawalRequests[_rewardToken][_pid][msg.sender];
        uint lockedUntil = pool.lockPeriod.add(block.timestamp);

        pushWithdrawalRequest(user, requests, _amount, lockedUntil);

        // Update Delegate Amount
        if (_rewardToken == address(xvsAddress)) {
            uint256 updatedAmount = user.amount.sub(user.pendingWithdrawals);
            _updateDelegate(address(msg.sender), uint96(updatedAmount));
        }

        emit ReqestedWithdrawal(msg.sender, _rewardToken, _pid, _amount);
    }

    /**
     * @notice Get unlocked withdrawal amount
     * @param _rewardToken The Reward Token Address
     * @param _pid The Pool Index
     * @param _user The User Address
     */
    function getEligibleWithdrawalAmount(address _rewardToken, uint256 _pid, address _user)
        external
        view
        returns (uint withdrawalAmount)
    {
        _ensureValidPool(_rewardToken, _pid);
        WithdrawalRequest[] storage requests = withdrawalRequests[_rewardToken][_pid][_user];
        // Since the requests are sorted by their unlock time, we can take
        // the entries from the end of the array and stop at the first
        // not-yet-eligible one
        for (uint i = requests.length; i > 0 && isUnlocked(requests[i - 1]); --i) {
            withdrawalAmount = withdrawalAmount.add(requests[i - 1].amount);
        }
        return withdrawalAmount;
    }

    /**
     * @notice Get requested amount
     * @param _rewardToken The Reward Token Address
     * @param _pid The Pool Index
     * @param _user The User Address
     */
    function getRequestedAmount(address _rewardToken, uint256 _pid, address _user)
        external
        view
        returns (uint256)
    {
        _ensureValidPool(_rewardToken, _pid);
        UserInfo storage user = userInfos[_rewardToken][_pid][_user];
        return user.pendingWithdrawals;
    }

    /**
     * @notice Returns the array of withdrawal requests that have not been executed yet
     * @param _rewardToken The Reward Token Address
     * @param _pid The Pool Index
     * @param _user The User Address
     */
    function getWithdrawalRequests(address _rewardToken, uint256 _pid, address _user)
        external
        view
        returns (WithdrawalRequest[] memory)
    {
        _ensureValidPool(_rewardToken, _pid);
        return withdrawalRequests[_rewardToken][_pid][_user];
    }

    // View function to see pending XVSs on frontend.
    function pendingReward(address _rewardToken, uint256 _pid, address _user)
        external
        view
        returns (uint256)
    {
        _ensureValidPool(_rewardToken, _pid);
        PoolInfo storage pool = poolInfos[_rewardToken][_pid];
        UserInfo storage user = userInfos[_rewardToken][_pid][_user];
        uint256 accRewardPerShare = pool.accRewardPerShare;
        uint256 supply = pool.token.balanceOf(address(this));
        uint256 curBlockNumber = block.number;
        uint256 rewardTokenPerBlock = rewardTokenAmountsPerBlock[_rewardToken];
        if (curBlockNumber > pool.lastRewardBlock && supply != 0) {
            uint256 multiplier = curBlockNumber.sub(pool.lastRewardBlock);
            uint256 reward =
                multiplier.mul(rewardTokenPerBlock).mul(pool.allocPoint).div(
                    totalAllocPoints[_rewardToken]
                );
            accRewardPerShare = accRewardPerShare.add(
                reward.mul(1e12).div(supply)
            );
        }
        return user.amount.mul(accRewardPerShare).div(1e12).sub(user.rewardDebt);
    }

    // Update reward vairables for all pools. Be careful of gas spending!
    function massUpdatePools(address _rewardToken) public {
        uint256 length = poolInfos[_rewardToken].length;
        for (uint256 pid = 0; pid < length; ++pid) {
            _updatePool(_rewardToken, pid);
        }
    }

    function updatePool(address _rewardToken, uint256 _pid)
        external
    {
        _ensureValidPool(_rewardToken, _pid);
        _updatePool(_rewardToken, _pid);
    }

    // Update reward variables of the given pool to be up-to-date.
    function _updatePool(address _rewardToken, uint256 _pid)
        internal
    {
        PoolInfo storage pool = poolInfos[_rewardToken][_pid];
        if (block.number <= pool.lastRewardBlock) {
            return;
        }
        uint256 supply = pool.token.balanceOf(address(this));
        if (supply == 0) {
            pool.lastRewardBlock = block.number;
            return;
        }
        uint256 curBlockNumber = block.number;
        uint256 multiplier = curBlockNumber.sub(pool.lastRewardBlock);
        uint256 reward =
            multiplier.mul(rewardTokenAmountsPerBlock[_rewardToken]).mul(pool.allocPoint).div(
                totalAllocPoints[_rewardToken]
            );
        pool.accRewardPerShare = pool.accRewardPerShare.add(
            reward.mul(1e12).div(supply)
        );
        pool.lastRewardBlock = block.number;
    }

    function _ensureValidPool(address rewardToken, uint256 pid) internal view {
        require(pid < poolInfos[rewardToken].length , "vault: pool exists?");
    }

    // Get user info with reward token address and pid
    function getUserInfo(
        address _rewardToken,
        uint256 _pid,
        address _user
    )
        external
        view
        returns (uint256 amount, uint256 rewardDebt, uint256 pendingWithdrawals)
    {
        _ensureValidPool(_rewardToken, _pid);
        UserInfo storage user = userInfos[_rewardToken][_pid][_user];
        amount = user.amount;
        rewardDebt = user.rewardDebt;
        pendingWithdrawals = user.pendingWithdrawals;
    }

    /**
     * @notice Get the XVS stake balance of an account (excluding the pending withdrawals)
     * @param account The address of the account to check
     * @return The balance that user staked
     */
    function getStakeAmount(address account) internal view returns (uint96) {
        require(xvsAddress != address(0), "XVSVault::getStakeAmount: xvs address is not set");

        PoolInfo[] storage poolInfo = poolInfos[xvsAddress];

        uint256 length = poolInfo.length;
        for (uint256 pid = 0; pid < length; ++pid) {
            if (address(poolInfo[pid].token) == address(xvsAddress)) {
                UserInfo storage user = userInfos[xvsAddress][pid][account];
                return uint96(user.amount.sub(user.pendingWithdrawals));
            }
        }
        return uint96(0);
    }

    /**
     * @notice Update Delegates - voting power
     * @param delegator The address of Delegator
     * @param amount Updated delegate amount
     */
    function _updateDelegate(address delegator, uint96 amount) internal {
        address currentDelegate = delegates[delegator];

        if (currentDelegate != address(0)) {
            uint32 delegateRepNum = numCheckpoints[currentDelegate];
            uint96 delegateRepOld = delegateRepNum > 0 ? checkpoints[currentDelegate][delegateRepNum - 1].votes : 0;
            _writeCheckpoint(currentDelegate, delegateRepNum, delegateRepOld, amount);
        }
    }

    /**
     * @notice Delegate votes from `msg.sender` to `delegatee`
     * @param delegatee The address to delegate votes to
     */
    function delegate(address delegatee) external {
        return _delegate(msg.sender, delegatee);
    }

    /**
     * @notice Delegates votes from signatory to `delegatee`
     * @param delegatee The address to delegate votes to
     * @param nonce The contract state required to match the signature
     * @param expiry The time at which to expire the signature
     * @param v The recovery byte of the signature
     * @param r Half of the ECDSA signature pair
     * @param s Half of the ECDSA signature pair
     */
    function delegateBySig(address delegatee, uint nonce, uint expiry, uint8 v, bytes32 r, bytes32 s)
        external
    {
        bytes32 domainSeparator = keccak256(abi.encode(DOMAIN_TYPEHASH, keccak256(bytes("XVSVault")), getChainId(), address(this)));
        bytes32 structHash = keccak256(abi.encode(DELEGATION_TYPEHASH, delegatee, nonce, expiry));
        bytes32 digest = keccak256(abi.encodePacked("\x19\x01", domainSeparator, structHash));
        address signatory = ECDSA.recover(digest, v, r, s);
        require(nonce == nonces[signatory]++, "XVSVault::delegateBySig: invalid nonce");
        require(block.timestamp <= expiry, "XVSVault::delegateBySig: signature expired");
        return _delegate(signatory, delegatee);
    }

    /**
     * @notice Gets the current votes balance for `account`
     * @param account The address to get votes balance
     * @return The number of current votes for `account`
     */
    function getCurrentVotes(address account) external view returns (uint96) {
        uint32 nCheckpoints = numCheckpoints[account];
        return nCheckpoints > 0 ? checkpoints[account][nCheckpoints - 1].votes : 0;
    }

    function _delegate(address delegator, address delegatee) internal {
        address currentDelegate = delegates[delegator];
        uint96 delegatorBalance = getStakeAmount(delegator);
        delegates[delegator] = delegatee;

        emit DelegateChanged(delegator, currentDelegate, delegatee);

        _moveDelegates(currentDelegate, delegatee, delegatorBalance);
    }

    function _moveDelegates(address srcRep, address dstRep, uint96 amount) internal {
        if (srcRep != dstRep && amount > 0) {
            if (srcRep != address(0)) {
                uint32 srcRepNum = numCheckpoints[srcRep];
                uint96 srcRepOld = srcRepNum > 0 ? checkpoints[srcRep][srcRepNum - 1].votes : 0;
                uint96 srcRepNew = sub96(srcRepOld, amount, "XVSVault::_moveVotes: vote amount underflows");
                _writeCheckpoint(srcRep, srcRepNum, srcRepOld, srcRepNew);
            }

            if (dstRep != address(0)) {
                uint32 dstRepNum = numCheckpoints[dstRep];
                uint96 dstRepOld = dstRepNum > 0 ? checkpoints[dstRep][dstRepNum - 1].votes : 0;
                uint96 dstRepNew = add96(dstRepOld, amount, "XVSVault::_moveVotes: vote amount overflows");
                _writeCheckpoint(dstRep, dstRepNum, dstRepOld, dstRepNew);
            }
        }
    }

    function _writeCheckpoint(address delegatee, uint32 nCheckpoints, uint96 oldVotes, uint96 newVotes) internal {
        uint32 blockNumber = safe32(block.number, "XVSVault::_writeCheckpoint: block number exceeds 32 bits");

        if (nCheckpoints > 0 && checkpoints[delegatee][nCheckpoints - 1].fromBlock == blockNumber) {
            checkpoints[delegatee][nCheckpoints - 1].votes = newVotes;
        } else {
            checkpoints[delegatee][nCheckpoints] = Checkpoint(blockNumber, newVotes);
            numCheckpoints[delegatee] = nCheckpoints + 1;
        }

        emit DelegateVotesChanged(delegatee, oldVotes, newVotes);
    }

    function safe32(uint n, string memory errorMessage) internal pure returns (uint32) {
        require(n < 2**32, errorMessage);
        return uint32(n);
    }

    function safe96(uint n, string memory errorMessage) internal pure returns (uint96) {
        require(n < 2**96, errorMessage);
        return uint96(n);
    }

    function add96(uint96 a, uint96 b, string memory errorMessage) internal pure returns (uint96) {
        uint96 c = a + b;
        require(c >= a, errorMessage);
        return c;
    }

    function sub96(uint96 a, uint96 b, string memory errorMessage) internal pure returns (uint96) {
        require(b <= a, errorMessage);
        return a - b;
    }

    function getChainId() internal pure returns (uint) {
        uint256 chainId;
        assembly { chainId := chainid() }
        return chainId;
    }

    /**
     * @notice Determine the xvs stake balance for an account
     * @param account The address of the account to check
     * @param blockNumber The block number to get the vote balance at
     * @return The balance that user staked
     */
    function getPriorVotes(address account, uint256 blockNumber) external view returns (uint96) {
        require(blockNumber < block.number, "XVSVault::getPriorVotes: not yet determined");

        uint32 nCheckpoints = numCheckpoints[account];
        if (nCheckpoints == 0) {
            return 0;
        }

        // First check most recent balance
        if (checkpoints[account][nCheckpoints - 1].fromBlock <= blockNumber) {
            return checkpoints[account][nCheckpoints - 1].votes;
        }

        // Next check implicit zero balance
        if (checkpoints[account][0].fromBlock > blockNumber) {
            return 0;
        }

        uint32 lower = 0;
        uint32 upper = nCheckpoints - 1;
        while (upper > lower) {
            uint32 center = upper - (upper - lower) / 2; // ceil, avoiding overflow
            Checkpoint memory cp = checkpoints[account][center];
            if (cp.fromBlock == blockNumber) {
                return cp.votes;
            } else if (cp.fromBlock < blockNumber) {
                lower = center;
            } else {
                upper = center - 1;
            }
        }
        return checkpoints[account][lower].votes;
    }

    /**
     * @dev Returns the address of the current admin
     */
    function getAdmin() external view returns (address) {
        return admin;
    }

    /**
     * @dev Burn the current admin
     */
    function burnAdmin() external onlyAdmin {
        emit AdminTransferred(admin, address(0));
        admin = address(0);
    }

    /*** Admin Functions ***/

    function _become(XVSVaultProxy xvsVaultProxy) external {
        require(msg.sender == xvsVaultProxy.admin(), "only proxy admin can change brains");
        require(xvsVaultProxy._acceptImplementation() == 0, "change not authorized");
    }

    function setXvsStore(address _xvs, address _xvsStore) external onlyAdmin {
        address oldXvsContract = xvsAddress;
        address oldStore = xvsStore;
        xvsAddress = _xvs;
        xvsStore = _xvsStore;

        _notEntered = true;

        emit StoreUpdated(oldXvsContract, oldStore, _xvs, _xvsStore);
    }
}

pragma solidity ^0.5.16;

contract XVSVaultErrorReporter {
    enum Error {
        NO_ERROR,
        UNAUTHORIZED
    }

    enum FailureInfo {
        ACCEPT_ADMIN_PENDING_ADMIN_CHECK,
        ACCEPT_PENDING_IMPLEMENTATION_ADDRESS_CHECK,
        SET_PENDING_ADMIN_OWNER_CHECK,
        SET_PENDING_IMPLEMENTATION_OWNER_CHECK
    }

    /**
      * @dev `error` corresponds to enum Error; `info` corresponds to enum FailureInfo, and `detail` is an arbitrary
      * contract-specific code that enables us to report opaque error codes from upgradeable contracts.
      **/
    event Failure(uint error, uint info, uint detail);

    /**
      * @dev use this when reporting a known error from the money market or a non-upgradeable collaborator
      */
    function fail(Error err, FailureInfo info) internal returns (uint) {
        emit Failure(uint(err), uint(info), 0);

        return uint(err);
    }

    /**
      * @dev use this when reporting an opaque error from an upgradeable collaborator contract
      */
    function failOpaque(Error err, FailureInfo info, uint opaqueError) internal returns (uint) {
        emit Failure(uint(err), uint(info), opaqueError);

        return uint(err);
    }
}

pragma solidity ^0.5.16;
import "../Utils/SafeMath.sol";
import "../Utils/IBEP20.sol";

contract XVSVaultAdminStorage {
    /**
    * @notice Administrator for this contract
    */
    address public admin;

    /**
    * @notice Pending administrator for this contract
    */
    address public pendingAdmin;

    /**
    * @notice Active brains of XVS Vault
    */
    address public implementation;

    /**
    * @notice Pending brains of XVS Vault
    */
    address public pendingXVSVaultImplementation;
}

contract XVSVaultStorage is XVSVaultAdminStorage {
    /// @notice Guard variable for re-entrancy checks
    bool internal _notEntered;

    /// @notice The reward token store
    address public xvsStore;

    /// @notice The xvs token address
    address public xvsAddress;

    // Reward tokens created per block indentified by reward token address.
    mapping(address => uint256) public rewardTokenAmountsPerBlock;

    /// @notice Info of each user.
    struct UserInfo {
        uint256 amount;
        uint256 rewardDebt;
        uint256 pendingWithdrawals;
    }

    // Info of each pool.
    struct PoolInfo {
        IBEP20 token;               // Address of token contract to stake.
        uint256 allocPoint;         // How many allocation points assigned to this pool.
        uint256 lastRewardBlock;    // Last block number that reward tokens distribution occurs.
        uint256 accRewardPerShare;  // Accumulated per share, times 1e12. See below.
        uint256 lockPeriod;         // Min time between withdrawal request and its execution.
    }

    // Infomation about a withdrawal request
    struct WithdrawalRequest {
        uint256 amount;
        uint256 lockedUntil;
    }

    // Info of each user that stakes tokens.
    mapping(address => mapping(uint256 => mapping(address => UserInfo))) userInfos;

    // Info of each pool.
    mapping(address => PoolInfo[]) public poolInfos;

    // Total allocation points. Must be the sum of all allocation points in all pools.
    mapping(address => uint256) public totalAllocPoints;

    // Info of requested but not yet executed withdrawals
    mapping(address => mapping(uint256 => mapping(address => WithdrawalRequest[]))) withdrawalRequests;

    /// @notice A record of each accounts delegate
    mapping (address => address) public delegates;

    /// @notice A checkpoint for marking number of votes from a given block
    struct Checkpoint {
        uint32 fromBlock;
        uint96 votes;
    }

    /// @notice A record of votes checkpoints for each account, by index
    mapping (address => mapping (uint32 => Checkpoint)) public checkpoints;

    /// @notice The number of checkpoints for each account
    mapping (address => uint32) public numCheckpoints;

    /// @notice A record of states for signing / validating signatures
    mapping (address => uint) public nonces;

    /// @notice The EIP-712 typehash for the contract's domain
    bytes32 public constant DOMAIN_TYPEHASH = keccak256("EIP712Domain(string name,uint256 chainId,address verifyingContract)");

    /// @notice The EIP-712 typehash for the delegation struct used by the contract
    bytes32 public constant DELEGATION_TYPEHASH = keccak256("Delegation(address delegatee,uint256 nonce,uint256 expiry)");

}

pragma solidity ^0.5.0;

/**
 * @dev Interface of the BEP20 standard as defined in the EIP. Does not include
 * the optional functions; to access them see {BEP20Detailed}.
 */
interface IBEP20 {
    /**
     * @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 ^0.5.0;

import "./IBEP20.sol";
import "./SafeMath.sol";
import "./Address.sol";

/**
 * @title SafeBEP20
 * @dev Wrappers around BEP20 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 SafeBEP20 for BEP20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeBEP20 {
    using SafeMath for uint256;
    using Address for address;

    function safeTransfer(IBEP20 token, address to, uint256 value) internal {
        callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(IBEP20 token, address from, address to, uint256 value) internal {
        callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    function safeApprove(IBEP20 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),
            "SafeBEP20: approve from non-zero to non-zero allowance"
        );
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(IBEP20 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(IBEP20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeBEP20: 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(IBEP20 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.

        // A Solidity high level call has three parts:
        //  1. The target address is checked to verify it contains contract code
        //  2. The call itself is made, and success asserted
        //  3. The return value is decoded, which in turn checks the size of the returned data.
        // solhint-disable-next-line max-line-length
        require(address(token).isContract(), "SafeBEP20: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = address(token).call(data);
        require(success, "SafeBEP20: low-level call failed");

        if (returndata.length > 0) { // Return data is optional
            // solhint-disable-next-line max-line-length
            require(abi.decode(returndata, (bool)), "SafeBEP20: BEP20 operation did not succeed");
        }
    }
}

// SPDX-License-Identifier: MIT
// Adapted from OpenZeppelin Contracts v4.3.2 (utils/cryptography/ECDSA.sol)

// SPDX-Copyright-Text: OpenZeppelin, 2021
// SPDX-Copyright-Text: Venus, 2021

pragma solidity ^0.5.16;

/**
 * @dev Elliptic Curve Digital Signature Algorithm (ECDSA) operations.
 *
 * These functions can be used to verify that a message was signed by the holder
 * of the private keys of a given address.
 */
contract ECDSA {
    enum RecoverError {
        NoError,
        InvalidSignature,
        InvalidSignatureLength,
        InvalidSignatureS,
        InvalidSignatureV
    }

    function _throwError(RecoverError error) private pure {
        if (error == RecoverError.NoError) {
            return; // no error: do nothing
        } else if (error == RecoverError.InvalidSignature) {
            revert("ECDSA: invalid signature");
        } else if (error == RecoverError.InvalidSignatureLength) {
            revert("ECDSA: invalid signature length");
        } else if (error == RecoverError.InvalidSignatureS) {
            revert("ECDSA: invalid signature 's' value");
        } else if (error == RecoverError.InvalidSignatureV) {
            revert("ECDSA: invalid signature 'v' value");
        }
    }

    /**
     * @dev Returns the address that signed a hashed message (`hash`) with
     * `signature`. This address can then be used for verification purposes.
     *
     * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     * this is by receiving a hash of the original message (which may otherwise
     * be too long), and then calling {toEthSignedMessageHash} on it.
     */
    function recover(
        bytes32 hash,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal pure returns (address) {
        (address recovered, RecoverError error) = tryRecover(hash, v, r, s);
        _throwError(error);
        return recovered;
    }

    /**
     * @dev Returns the address that signed a hashed message (`hash`) with
     * `signature` or error string. This address can then be used for verification purposes.
     *
     * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     * this is by receiving a hash of the original message (which may otherwise
     * be too long), and then calling {toEthSignedMessageHash} on it.
     *
     * Documentation for signature generation:
     * - with https://web3js.readthedocs.io/en/v1.3.4/web3-eth-accounts.html#sign[Web3.js]
     * - with https://docs.ethers.io/v5/api/signer/#Signer-signMessage[ethers]
     *
     * _Available since v4.3._
     */
    function tryRecover(
        bytes32 hash,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal pure returns (address, RecoverError) {
        // EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
        // unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
        // the valid range for s in (301): 0 < s < secp256k1n ÷ 2 + 1, and for v in (302): v ∈ {27, 28}. Most
        // signatures from current libraries generate a unique signature with an s-value in the lower half order.
        //
        // If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
        // with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
        // vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
        // these malleable signatures as well.
        if (uint256(s) > 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0) {
            return (address(0), RecoverError.InvalidSignatureS);
        }
        if (v != 27 && v != 28) {
            return (address(0), RecoverError.InvalidSignatureV);
        }

        // If the signature is valid (and not malleable), return the signer address
        address signer = ecrecover(hash, v, r, s);
        if (signer == address(0)) {
            return (address(0), RecoverError.InvalidSignature);
        }

        return (signer, RecoverError.NoError);
    }
}

pragma solidity ^0.5.0;

/**
 * @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;
    }
}

pragma solidity ^0.5.5;

/**
 * @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) {
        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
        // for accounts without code, i.e. `keccak256('')`
        bytes32 codehash;
        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly { codehash := extcodehash(account) }
        return (codehash != accountHash && codehash != 0x0);
    }

    /**
     * @dev Converts an `address` into `address payable`. Note that this is
     * simply a type cast: the actual underlying value is not changed.
     *
     * _Available since v2.4.0._
     */
    function toPayable(address account) internal pure returns (address payable) {
        return address(uint160(account));
    }

    /**
     * @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].
     *
     * _Available since v2.4.0._
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        // solhint-disable-next-line avoid-call-value
        // solium-disable-next-line security/no-call-value
        (bool success, ) = recipient.call.value(amount)("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }
}

{
  "optimizer": {
    "enabled": true,
    "runs": 200
  },
  "outputSelection": {
    "*": {
      "*": [
        "evm.bytecode",
        "evm.deployedBytecode",
        "devdoc",
        "userdoc",
        "metadata",
        "abi"
      ]
    }
  }
}

• No Contract Security Audit Submitted- Submit Audit Here

[{"inputs":[],"payable":false,"stateMutability":"nonpayable","type":"constructor"},{"anonymous":false,"inputs":[{"indexed":false,"internalType":"uint256","name":"error","type":"uint256"},{"indexed":false,"internalType":"uint256","name":"info","type":"uint256"},{"indexed":false,"internalType":"uint256","name":"detail","type":"uint256"}],"name":"Failure","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"internalType":"address","name":"oldAdmin","type":"address"},{"indexed":false,"internalType":"address","name":"newAdmin","type":"address"}],"name":"NewAdmin","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"internalType":"address","name":"oldImplementation","type":"address"},{"indexed":false,"internalType":"address","name":"newImplementation","type":"address"}],"name":"NewImplementation","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"internalType":"address","name":"oldPendingAdmin","type":"address"},{"indexed":false,"internalType":"address","name":"newPendingAdmin","type":"address"}],"name":"NewPendingAdmin","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"internalType":"address","name":"oldPendingImplementation","type":"address"},{"indexed":false,"internalType":"address","name":"newPendingImplementation","type":"address"}],"name":"NewPendingImplementation","type":"event"},{"payable":true,"stateMutability":"payable","type":"fallback"},{"constant":false,"inputs":[],"name":"_acceptAdmin","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[],"name":"_acceptImplementation","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"newPendingAdmin","type":"address"}],"name":"_setPendingAdmin","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"internalType":"address","name":"newPendingImplementation","type":"address"}],"name":"_setPendingImplementation","outputs":[{"internalType":"uint256","name":"","type":"uint256"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"admin","outputs":[{"internalType":"address","name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"implementation","outputs":[{"internalType":"address","name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"pendingAdmin","outputs":[{"internalType":"address","name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"pendingXVSVaultImplementation","outputs":[{"internalType":"address","name":"","type":"address"}],"payable":false,"stateMutability":"view","type":"function"}]

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