// File: contracts/eip/interface/IERC20.sol



// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.0;

/**
 * @title ERC20 interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
interface IERC20 {
    function totalSupply() external view returns (uint256);

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

    function allowance(address owner, address spender) external view returns (uint256);

    function transfer(address to, uint256 value) external returns (bool);

    function approve(address spender, uint256 value) external returns (bool);

    function transferFrom(
        address from,
        address to,
        uint256 value
    ) external returns (bool);

    event Transfer(address indexed from, address indexed to, uint256 value);

    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// File: contracts/eip/interface/IERC20Metadata.sol



// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.0;

/**
 * @title ERC20Metadata interface
 * @dev see https://github.com/ethereum/EIPs/issues/20
 */
interface IERC20Metadata {
    function name() external view returns (string memory);

    function symbol() external view returns (string memory);

    function decimals() external view returns (uint8);
}

// File: contracts/extension/ContractMetadata.sol



// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.0;

import "./interface/IContractMetadata.sol";

/**
 *  @title   Contract Metadata
 *  @notice  Thirdweb's `ContractMetadata` is a contract extension for any base contracts. It lets you set a metadata URI
 *           for you contract.
 *           Additionally, `ContractMetadata` is necessary for NFT contracts that want royalties to get distributed on OpenSea.
 */

abstract contract ContractMetadata is IContractMetadata {
    /// @notice Returns the contract metadata URI.
    string public override contractURI;

    /**
     *  @notice         Lets a contract admin set the URI for contract-level metadata.
     *  @dev            Caller should be authorized to setup contractURI, e.g. contract admin.
     *                  See {_canSetContractURI}.
     *                  Emits {ContractURIUpdated Event}.
     *
     *  @param _uri     keccak256 hash of the role. e.g. keccak256("TRANSFER_ROLE")
     */
    function setContractURI(string memory _uri) external override {
        if (!_canSetContractURI()) {
            revert("Not authorized");
        }

        _setupContractURI(_uri);
    }

    /// @dev Lets a contract admin set the URI for contract-level metadata.
    function _setupContractURI(string memory _uri) internal {
        string memory prevURI = contractURI;
        contractURI = _uri;

        emit ContractURIUpdated(prevURI, _uri);
    }

    /// @dev Returns whether contract metadata can be set in the given execution context.
    function _canSetContractURI() internal view virtual returns (bool);
}

// File: contracts/extension/Permissions.sol



// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.0;

import "./interface/IPermissions.sol";
import "../lib/TWStrings.sol";

/**
 *  @title   Permissions
 *  @dev     This contracts provides extending-contracts with role-based access control mechanisms
 */
contract Permissions is IPermissions {
    /// @dev Map from keccak256 hash of a role => a map from address => whether address has role.
    mapping(bytes32 => mapping(address => bool)) private _hasRole;

    /// @dev Map from keccak256 hash of a role to role admin. See {getRoleAdmin}.
    mapping(bytes32 => bytes32) private _getRoleAdmin;

    /// @dev Default admin role for all roles. Only accounts with this role can grant/revoke other roles.
    bytes32 public constant DEFAULT_ADMIN_ROLE = 0x00;

    /// @dev Modifier that checks if an account has the specified role; reverts otherwise.
    modifier onlyRole(bytes32 role) {
        _checkRole(role, msg.sender);
        _;
    }

    /**
     *  @notice         Checks whether an account has a particular role.
     *  @dev            Returns `true` if `account` has been granted `role`.
     *
     *  @param role     keccak256 hash of the role. e.g. keccak256("TRANSFER_ROLE")
     *  @param account  Address of the account for which the role is being checked.
     */
    function hasRole(bytes32 role, address account) public view override returns (bool) {
        return _hasRole[role][account];
    }

    /**
     *  @notice         Checks whether an account has a particular role;
     *                  role restrictions can be swtiched on and off.
     *
     *  @dev            Returns `true` if `account` has been granted `role`.
     *                  Role restrictions can be swtiched on and off:
     *                      - If address(0) has ROLE, then the ROLE restrictions
     *                        don't apply.
     *                      - If address(0) does not have ROLE, then the ROLE
     *                        restrictions will apply.
     *
     *  @param role     keccak256 hash of the role. e.g. keccak256("TRANSFER_ROLE")
     *  @param account  Address of the account for which the role is being checked.
     */
    function hasRoleWithSwitch(bytes32 role, address account) public view returns (bool) {
        if (!_hasRole[role][address(0)]) {
            return _hasRole[role][account];
        }

        return true;
    }

    /**
     *  @notice         Returns the admin role that controls the specified role.
     *  @dev            See {grantRole} and {revokeRole}.
     *                  To change a role's admin, use {_setRoleAdmin}.
     *
     *  @param role     keccak256 hash of the role. e.g. keccak256("TRANSFER_ROLE")
     */
    function getRoleAdmin(bytes32 role) external view override returns (bytes32) {
        return _getRoleAdmin[role];
    }

    /**
     *  @notice         Grants a role to an account, if not previously granted.
     *  @dev            Caller must have admin role for the `role`.
     *                  Emits {RoleGranted Event}.
     *
     *  @param role     keccak256 hash of the role. e.g. keccak256("TRANSFER_ROLE")
     *  @param account  Address of the account to which the role is being granted.
     */
    function grantRole(bytes32 role, address account) public virtual override {
        _checkRole(_getRoleAdmin[role], msg.sender);
        if (_hasRole[role][account]) {
            revert("Can only grant to non holders");
        }
        _setupRole(role, account);
    }

    /**
     *  @notice         Revokes role from an account.
     *  @dev            Caller must have admin role for the `role`.
     *                  Emits {RoleRevoked Event}.
     *
     *  @param role     keccak256 hash of the role. e.g. keccak256("TRANSFER_ROLE")
     *  @param account  Address of the account from which the role is being revoked.
     */
    function revokeRole(bytes32 role, address account) public virtual override {
        _checkRole(_getRoleAdmin[role], msg.sender);
        _revokeRole(role, account);
    }

    /**
     *  @notice         Revokes role from the account.
     *  @dev            Caller must have the `role`, with caller being the same as `account`.
     *                  Emits {RoleRevoked Event}.
     *
     *  @param role     keccak256 hash of the role. e.g. keccak256("TRANSFER_ROLE")
     *  @param account  Address of the account from which the role is being revoked.
     */
    function renounceRole(bytes32 role, address account) public virtual override {
        if (msg.sender != account) {
            revert("Can only renounce for self");
        }
        _revokeRole(role, account);
    }

    /// @dev Sets `adminRole` as `role`'s admin role.
    function _setRoleAdmin(bytes32 role, bytes32 adminRole) internal virtual {
        bytes32 previousAdminRole = _getRoleAdmin[role];
        _getRoleAdmin[role] = adminRole;
        emit RoleAdminChanged(role, previousAdminRole, adminRole);
    }

    /// @dev Sets up `role` for `account`
    function _setupRole(bytes32 role, address account) internal virtual {
        _hasRole[role][account] = true;
        emit RoleGranted(role, account, msg.sender);
    }

    /// @dev Revokes `role` from `account`
    function _revokeRole(bytes32 role, address account) internal virtual {
        _checkRole(role, account);
        delete _hasRole[role][account];
        emit RoleRevoked(role, account, msg.sender);
    }

    /// @dev Checks `role` for `account`. Reverts with a message including the required role.
    function _checkRole(bytes32 role, address account) internal view virtual {
        if (!_hasRole[role][account]) {
            revert(
                string(
                    abi.encodePacked(
                        "Permissions: account ",
                        TWStrings.toHexString(uint160(account), 20),
                        " is missing role ",
                        TWStrings.toHexString(uint256(role), 32)
                    )
                )
            );
        }
    }

    /// @dev Checks `role` for `account`. Reverts with a message including the required role.
    function _checkRoleWithSwitch(bytes32 role, address account) internal view virtual {
        if (!hasRoleWithSwitch(role, account)) {
            revert(
                string(
                    abi.encodePacked(
                        "Permissions: account ",
                        TWStrings.toHexString(uint160(account), 20),
                        " is missing role ",
                        TWStrings.toHexString(uint256(role), 32)
                    )
                )
            );
        }
    }
}

// File: contracts/extension/PermissionsEnumerable.sol



// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.0;

import "./interface/IPermissionsEnumerable.sol";
import "./Permissions.sol";

/**
 *  @title   PermissionsEnumerable
 *  @dev     This contracts provides extending-contracts with role-based access control mechanisms.
 *           Also provides interfaces to view all members with a given role, and total count of members.
 */
contract PermissionsEnumerable is IPermissionsEnumerable, Permissions {
    /**
     *  @notice A data structure to store data of members for a given role.
     *
     *  @param index    Current index in the list of accounts that have a role.
     *  @param members  map from index => address of account that has a role
     *  @param indexOf  map from address => index which the account has.
     */
    struct RoleMembers {
        uint256 index;
        mapping(uint256 => address) members;
        mapping(address => uint256) indexOf;
    }

    /// @dev map from keccak256 hash of a role to its members' data. See {RoleMembers}.
    mapping(bytes32 => RoleMembers) private roleMembers;

    /**
     *  @notice         Returns the role-member from a list of members for a role,
     *                  at a given index.
     *  @dev            Returns `member` who has `role`, at `index` of role-members list.
     *                  See struct {RoleMembers}, and mapping {roleMembers}
     *
     *  @param role     keccak256 hash of the role. e.g. keccak256("TRANSFER_ROLE")
     *  @param index    Index in list of current members for the role.
     *
     *  @return member  Address of account that has `role`
     */
    function getRoleMember(bytes32 role, uint256 index) external view override returns (address member) {
        uint256 currentIndex = roleMembers[role].index;
        uint256 check;

        for (uint256 i = 0; i < currentIndex; i += 1) {
            if (roleMembers[role].members[i] != address(0)) {
                if (check == index) {
                    member = roleMembers[role].members[i];
                    return member;
                }
                check += 1;
            } else if (hasRole(role, address(0)) && i == roleMembers[role].indexOf[address(0)]) {
                check += 1;
            }
        }
    }

    /**
     *  @notice         Returns total number of accounts that have a role.
     *  @dev            Returns `count` of accounts that have `role`.
     *                  See struct {RoleMembers}, and mapping {roleMembers}
     *
     *  @param role     keccak256 hash of the role. e.g. keccak256("TRANSFER_ROLE")
     *
     *  @return count   Total number of accounts that have `role`
     */
    function getRoleMemberCount(bytes32 role) external view override returns (uint256 count) {
        uint256 currentIndex = roleMembers[role].index;

        for (uint256 i = 0; i < currentIndex; i += 1) {
            if (roleMembers[role].members[i] != address(0)) {
                count += 1;
            }
        }
        if (hasRole(role, address(0))) {
            count += 1;
        }
    }

    /// @dev Revokes `role` from `account`, and removes `account` from {roleMembers}
    ///      See {_removeMember}
    function _revokeRole(bytes32 role, address account) internal override {
        super._revokeRole(role, account);
        _removeMember(role, account);
    }

    /// @dev Grants `role` to `account`, and adds `account` to {roleMembers}
    ///      See {_addMember}
    function _setupRole(bytes32 role, address account) internal override {
        super._setupRole(role, account);
        _addMember(role, account);
    }

    /// @dev adds `account` to {roleMembers}, for `role`
    function _addMember(bytes32 role, address account) internal {
        uint256 idx = roleMembers[role].index;
        roleMembers[role].index += 1;

        roleMembers[role].members[idx] = account;
        roleMembers[role].indexOf[account] = idx;
    }

    /// @dev removes `account` from {roleMembers}, for `role`
    function _removeMember(bytes32 role, address account) internal {
        uint256 idx = roleMembers[role].indexOf[account];

        delete roleMembers[role].members[idx];
        delete roleMembers[role].indexOf[account];
    }
}

// File: contracts/extension/Staking20Upgradeable.sol



// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.11;

import "@openzeppelin/contracts-upgradeable/security/ReentrancyGuardUpgradeable.sol";
import "../openzeppelin-presets/utils/math/SafeMath.sol";
import "../eip/interface/IERC20.sol";
import "../lib/CurrencyTransferLib.sol";

import "./interface/IStaking20.sol";

abstract contract Staking20Upgradeable is ReentrancyGuardUpgradeable, IStaking20 {
    /*///////////////////////////////////////////////////////////////
                            State variables / Mappings
    //////////////////////////////////////////////////////////////*/

    /// @dev The address of the native token wrapper contract.
    address internal immutable nativeTokenWrapper;

    ///@dev Address of ERC20 contract -- staked tokens belong to this contract.
    address public stakingToken;

    /// @dev Decimals of staking token.
    uint256 public stakingTokenDecimals;

    /// @dev Decimals of reward token.
    uint256 public rewardTokenDecimals;

    /// @dev List of accounts that have staked that token-id.
    address[] public stakersArray;

    /// @dev Total amount of tokens staked in the contract.
    uint256 public stakingTokenBalance;

    ///@dev Next staking condition Id. Tracks number of conditon updates so far.
    uint256 private nextConditionId;

    ///@dev Mapping staker address to Staker struct. See {struct IStaking20.Staker}.
    mapping(address => Staker) public stakers;

    ///@dev Mapping from condition Id to staking condition. See {struct IStaking721.StakingCondition}
    mapping(uint256 => StakingCondition) private stakingConditions;

    constructor(address _nativeTokenWrapper) {
        require(_nativeTokenWrapper != address(0), "address 0");

        nativeTokenWrapper = _nativeTokenWrapper;
    }

    function __Staking20_init(
        address _stakingToken,
        uint256 _stakingTokenDecimals,
        uint256 _rewardTokenDecimals
    ) internal onlyInitializing {
        __ReentrancyGuard_init();

        require(address(_stakingToken) != address(0), "token address 0");
        require(_stakingTokenDecimals != 0 && _rewardTokenDecimals != 0, "decimals 0");

        stakingToken = _stakingToken;
        stakingTokenDecimals = _stakingTokenDecimals;
        rewardTokenDecimals = _rewardTokenDecimals;
    }

    /*///////////////////////////////////////////////////////////////
                        External/Public Functions
    //////////////////////////////////////////////////////////////*/

    /**
     *  @notice    Stake ERC20 Tokens.
     *
     *  @dev       See {_stake}. Override that to implement custom logic.
     *
     *  @param _amount    Amount to stake.
     */
    function stake(uint256 _amount) external payable nonReentrant {
        _stake(_amount);
    }

    /**
     *  @notice    Withdraw staked ERC20 tokens.
     *
     *  @dev       See {_withdraw}. Override that to implement custom logic.
     *
     *  @param _amount    Amount to withdraw.
     */
    function withdraw(uint256 _amount) external nonReentrant {
        _withdraw(_amount);
    }

    /**
     *  @notice    Claim accumulated rewards.
     *
     *  @dev       See {_claimRewards}. Override that to implement custom logic.
     *             See {_calculateRewards} for reward-calculation logic.
     */
    function claimRewards() external nonReentrant {
        _claimRewards();
    }

    /**
     *  @notice  Set time unit. Set as a number of seconds.
     *           Could be specified as -- x * 1 hours, x * 1 days, etc.
     *
     *  @dev     Only admin/authorized-account can call it.
     *
     *  @param _timeUnit    New time unit.
     */
    function setTimeUnit(uint256 _timeUnit) external virtual {
        if (!_canSetStakeConditions()) {
            revert("Not authorized");
        }

        StakingCondition memory condition = stakingConditions[nextConditionId - 1];
        require(_timeUnit != condition.timeUnit, "Time-unit unchanged.");

        _setStakingCondition(_timeUnit, condition.rewardRatioNumerator, condition.rewardRatioDenominator);

        emit UpdatedTimeUnit(condition.timeUnit, _timeUnit);
    }

    /**
     *  @notice  Set rewards per unit of time.
     *           Interpreted as (numerator/denominator) rewards per second/per day/etc based on time-unit.
     *
     *           For e.g., ratio of 1/20 would mean 1 reward token for every 20 tokens staked.
     *
     *  @dev     Only admin/authorized-account can call it.
     *
     *  @param _numerator    Reward ratio numerator.
     *  @param _denominator  Reward ratio denominator.
     */
    function setRewardRatio(uint256 _numerator, uint256 _denominator) external virtual {
        if (!_canSetStakeConditions()) {
            revert("Not authorized");
        }

        StakingCondition memory condition = stakingConditions[nextConditionId - 1];
        require(
            _numerator != condition.rewardRatioNumerator || _denominator != condition.rewardRatioDenominator,
            "Reward ratio unchanged."
        );
        _setStakingCondition(condition.timeUnit, _numerator, _denominator);

        emit UpdatedRewardRatio(
            condition.rewardRatioNumerator,
            _numerator,
            condition.rewardRatioDenominator,
            _denominator
        );
    }

    /**
     *  @notice View amount staked and rewards for a user.
     *
     *  @param _staker          Address for which to calculated rewards.
     *  @return _tokensStaked   Amount of tokens staked.
     *  @return _rewards        Available reward amount.
     */
    function getStakeInfo(address _staker) external view virtual returns (uint256 _tokensStaked, uint256 _rewards) {
        _tokensStaked = stakers[_staker].amountStaked;
        _rewards = _availableRewards(_staker);
    }

    function getTimeUnit() public view returns (uint256 _timeUnit) {
        _timeUnit = stakingConditions[nextConditionId - 1].timeUnit;
    }

    function getRewardRatio() public view returns (uint256 _numerator, uint256 _denominator) {
        _numerator = stakingConditions[nextConditionId - 1].rewardRatioNumerator;
        _denominator = stakingConditions[nextConditionId - 1].rewardRatioDenominator;
    }

    /*///////////////////////////////////////////////////////////////
                            Internal Functions
    //////////////////////////////////////////////////////////////*/

    /// @dev Staking logic. Override to add custom logic.
    function _stake(uint256 _amount) internal virtual {
        require(_amount != 0, "Staking 0 tokens");

        address _stakingToken;
        if (stakingToken == CurrencyTransferLib.NATIVE_TOKEN) {
            _stakingToken = nativeTokenWrapper;
        } else {
            require(msg.value == 0, "Value not 0");
            _stakingToken = stakingToken;
        }

        if (stakers[_stakeMsgSender()].amountStaked > 0) {
            _updateUnclaimedRewardsForStaker(_stakeMsgSender());
        } else {
            stakersArray.push(_stakeMsgSender());
            stakers[_stakeMsgSender()].timeOfLastUpdate = block.timestamp;
            stakers[_stakeMsgSender()].conditionIdOflastUpdate = nextConditionId - 1;
        }

        uint256 balanceBefore = IERC20(_stakingToken).balanceOf(address(this));
        CurrencyTransferLib.transferCurrencyWithWrapper(
            stakingToken,
            _stakeMsgSender(),
            address(this),
            _amount,
            nativeTokenWrapper
        );
        uint256 actualAmount = IERC20(_stakingToken).balanceOf(address(this)) - balanceBefore;

        stakers[_stakeMsgSender()].amountStaked += actualAmount;
        stakingTokenBalance += actualAmount;

        emit TokensStaked(_stakeMsgSender(), actualAmount);
    }

    /// @dev Withdraw logic. Override to add custom logic.
    function _withdraw(uint256 _amount) internal virtual {
        uint256 _amountStaked = stakers[_stakeMsgSender()].amountStaked;
        require(_amount != 0, "Withdrawing 0 tokens");
        require(_amountStaked >= _amount, "Withdrawing more than staked");

        _updateUnclaimedRewardsForStaker(_stakeMsgSender());

        if (_amountStaked == _amount) {
            address[] memory _stakersArray = stakersArray;
            for (uint256 i = 0; i < _stakersArray.length; ++i) {
                if (_stakersArray[i] == _stakeMsgSender()) {
                    stakersArray[i] = _stakersArray[_stakersArray.length - 1];
                    stakersArray.pop();
                    break;
                }
            }
        }
        stakers[_stakeMsgSender()].amountStaked -= _amount;
        stakingTokenBalance -= _amount;

        CurrencyTransferLib.transferCurrencyWithWrapper(
            stakingToken,
            address(this),
            _stakeMsgSender(),
            _amount,
            nativeTokenWrapper
        );

        emit TokensWithdrawn(_stakeMsgSender(), _amount);
    }

    /// @dev Logic for claiming rewards. Override to add custom logic.
    function _claimRewards() internal virtual {
        uint256 rewards = stakers[_stakeMsgSender()].unclaimedRewards + _calculateRewards(_stakeMsgSender());

        require(rewards != 0, "No rewards");

        stakers[_stakeMsgSender()].timeOfLastUpdate = block.timestamp;
        stakers[_stakeMsgSender()].unclaimedRewards = 0;
        stakers[_stakeMsgSender()].conditionIdOflastUpdate = nextConditionId - 1;

        _mintRewards(_stakeMsgSender(), rewards);

        emit RewardsClaimed(_stakeMsgSender(), rewards);
    }

    /// @dev View available rewards for a user.
    function _availableRewards(address _staker) internal view virtual returns (uint256 _rewards) {
        if (stakers[_staker].amountStaked == 0) {
            _rewards = stakers[_staker].unclaimedRewards;
        } else {
            _rewards = stakers[_staker].unclaimedRewards + _calculateRewards(_staker);
        }
    }

    /// @dev Update unclaimed rewards for a users. Called for every state change for a user.
    function _updateUnclaimedRewardsForStaker(address _staker) internal virtual {
        uint256 rewards = _calculateRewards(_staker);
        stakers[_staker].unclaimedRewards += rewards;
        stakers[_staker].timeOfLastUpdate = block.timestamp;
        stakers[_staker].conditionIdOflastUpdate = nextConditionId - 1;
    }

    /// @dev Set staking conditions.
    function _setStakingCondition(
        uint256 _timeUnit,
        uint256 _numerator,
        uint256 _denominator
    ) internal virtual {
        require(_denominator != 0, "divide by 0");
        require(_timeUnit != 0, "time-unit can't be 0");
        uint256 conditionId = nextConditionId;
        nextConditionId += 1;

        stakingConditions[conditionId] = StakingCondition({
            timeUnit: _timeUnit,
            rewardRatioNumerator: _numerator,
            rewardRatioDenominator: _denominator,
            startTimestamp: block.timestamp,
            endTimestamp: 0
        });

        if (conditionId > 0) {
            stakingConditions[conditionId - 1].endTimestamp = block.timestamp;
        }
    }

    /// @dev Calculate rewards for a staker.
    function _calculateRewards(address _staker) internal view virtual returns (uint256 _rewards) {
        Staker memory staker = stakers[_staker];

        uint256 _stakerConditionId = staker.conditionIdOflastUpdate;
        uint256 _nextConditionId = nextConditionId;

        for (uint256 i = _stakerConditionId; i < _nextConditionId; i += 1) {
            StakingCondition memory condition = stakingConditions[i];

            uint256 startTime = i != _stakerConditionId ? condition.startTimestamp : staker.timeOfLastUpdate;
            uint256 endTime = condition.endTimestamp != 0 ? condition.endTimestamp : block.timestamp;

            (bool noOverflowProduct, uint256 rewardsProduct) = SafeMath.tryMul(
                (endTime - startTime) * staker.amountStaked,
                condition.rewardRatioNumerator
            );
            (bool noOverflowSum, uint256 rewardsSum) = SafeMath.tryAdd(
                _rewards,
                (rewardsProduct / condition.timeUnit) / condition.rewardRatioDenominator
            );

            _rewards = noOverflowProduct && noOverflowSum ? rewardsSum : _rewards;
        }

        (, _rewards) = SafeMath.tryMul(_rewards, 10**rewardTokenDecimals);

        _rewards /= (10**stakingTokenDecimals);
    }

    /*////////////////////////////////////////////////////////////////////
        Optional hooks that can be implemented in the derived contract
    ///////////////////////////////////////////////////////////////////*/

    /// @dev Exposes the ability to override the msg sender -- support ERC2771.
    function _stakeMsgSender() internal virtual returns (address) {
        return msg.sender;
    }

    /*///////////////////////////////////////////////////////////////
        Virtual functions to be implemented in derived contract
    //////////////////////////////////////////////////////////////*/

    /**
     *  @notice View total rewards available in the staking contract.
     *
     */
    function getRewardTokenBalance() external view virtual returns (uint256 _rewardsAvailableInContract);

    /**
     *  @dev    Mint/Transfer ERC20 rewards to the staker. Must override.
     *
     *  @param _staker    Address for which to calculated rewards.
     *  @param _rewards   Amount of tokens to be given out as reward.
     *
     *  For example, override as below to mint ERC20 rewards:
     *
     * ```
     *  function _mintRewards(address _staker, uint256 _rewards) internal override {
     *
     *      TokenERC20(rewardTokenAddress).mintTo(_staker, _rewards);
     *
     *  }
     * ```
     */
    function _mintRewards(address _staker, uint256 _rewards) internal virtual;

    /**
     *  @dev    Returns whether staking restrictions can be set in given execution context.
     *          Must override.
     *
     *
     *  For example, override as below to restrict access to admin:
     *
     * ```
     *  function _canSetStakeConditions() internal override {
     *
     *      return msg.sender == adminAddress;
     *
     *  }
     * ```
     */
    function _canSetStakeConditions() internal view virtual returns (bool);
}

// File: contracts/extension/interface/IContractMetadata.sol



// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.0;

/**
 *  Thirdweb's `ContractMetadata` is a contract extension for any base contracts. It lets you set a metadata URI
 *  for you contract.
 *
 *  Additionally, `ContractMetadata` is necessary for NFT contracts that want royalties to get distributed on OpenSea.
 */

interface IContractMetadata {
    /// @dev Returns the metadata URI of the contract.
    function contractURI() external view returns (string memory);

    /**
     *  @dev Sets contract URI for the storefront-level metadata of the contract.
     *       Only module admin can call this function.
     */
    function setContractURI(string calldata _uri) external;

    /// @dev Emitted when the contract URI is updated.
    event ContractURIUpdated(string prevURI, string newURI);
}

// File: contracts/extension/interface/IPermissions.sol



// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.0;

/**
 * @dev External interface of AccessControl declared to support ERC165 detection.
 */
interface IPermissions {
    /**
     * @dev Emitted when `newAdminRole` is set as ``role``'s admin role, replacing `previousAdminRole`
     *
     * `DEFAULT_ADMIN_ROLE` is the starting admin for all roles, despite
     * {RoleAdminChanged} not being emitted signaling this.
     *
     * _Available since v3.1._
     */
    event RoleAdminChanged(bytes32 indexed role, bytes32 indexed previousAdminRole, bytes32 indexed newAdminRole);

    /**
     * @dev Emitted when `account` is granted `role`.
     *
     * `sender` is the account that originated the contract call, an admin role
     * bearer except when using {AccessControl-_setupRole}.
     */
    event RoleGranted(bytes32 indexed role, address indexed account, address indexed sender);

    /**
     * @dev Emitted when `account` is revoked `role`.
     *
     * `sender` is the account that originated the contract call:
     *   - if using `revokeRole`, it is the admin role bearer
     *   - if using `renounceRole`, it is the role bearer (i.e. `account`)
     */
    event RoleRevoked(bytes32 indexed role, address indexed account, address indexed sender);

    /**
     * @dev Returns `true` if `account` has been granted `role`.
     */
    function hasRole(bytes32 role, address account) external view returns (bool);

    /**
     * @dev Returns the admin role that controls `role`. See {grantRole} and
     * {revokeRole}.
     *
     * To change a role's admin, use {AccessControl-_setRoleAdmin}.
     */
    function getRoleAdmin(bytes32 role) external view returns (bytes32);

    /**
     * @dev Grants `role` to `account`.
     *
     * If `account` had not been already granted `role`, emits a {RoleGranted}
     * event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function grantRole(bytes32 role, address account) external;

    /**
     * @dev Revokes `role` from `account`.
     *
     * If `account` had been granted `role`, emits a {RoleRevoked} event.
     *
     * Requirements:
     *
     * - the caller must have ``role``'s admin role.
     */
    function revokeRole(bytes32 role, address account) external;

    /**
     * @dev Revokes `role` from the calling account.
     *
     * Roles are often managed via {grantRole} and {revokeRole}: this function's
     * purpose is to provide a mechanism for accounts to lose their privileges
     * if they are compromised (such as when a trusted device is misplaced).
     *
     * If the calling account had been granted `role`, emits a {RoleRevoked}
     * event.
     *
     * Requirements:
     *
     * - the caller must be `account`.
     */
    function renounceRole(bytes32 role, address account) external;
}

// File: contracts/extension/interface/IPermissionsEnumerable.sol



// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.0;

import "./IPermissions.sol";

/**
 * @dev External interface of AccessControlEnumerable declared to support ERC165 detection.
 */
interface IPermissionsEnumerable is IPermissions {
    /**
     * @dev Returns one of the accounts that have `role`. `index` must be a
     * value between 0 and {getRoleMemberCount}, non-inclusive.
     *
     * Role bearers are not sorted in any particular way, and their ordering may
     * change at any point.
     *
     * WARNING: When using {getRoleMember} and {getRoleMemberCount}, make sure
     * you perform all queries on the same block. See the following
     * [forum post](https://forum.openzeppelin.com/t/iterating-over-elements-on-enumerableset-in-openzeppelin-contracts/2296)
     * for more information.
     */
    function getRoleMember(bytes32 role, uint256 index) external view returns (address);

    /**
     * @dev Returns the number of accounts that have `role`. Can be used
     * together with {getRoleMember} to enumerate all bearers of a role.
     */
    function getRoleMemberCount(bytes32 role) external view returns (uint256);
}

// File: contracts/extension/interface/IStaking20.sol



// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.11;

interface IStaking20 {
    /// @dev Emitted when tokens are staked.
    event TokensStaked(address indexed staker, uint256 amount);

    /// @dev Emitted when a tokens are withdrawn.
    event TokensWithdrawn(address indexed staker, uint256 amount);

    /// @dev Emitted when a staker claims staking rewards.
    event RewardsClaimed(address indexed staker, uint256 rewardAmount);

    /// @dev Emitted when contract admin updates timeUnit.
    event UpdatedTimeUnit(uint256 oldTimeUnit, uint256 newTimeUnit);

    /// @dev Emitted when contract admin updates rewardsPerUnitTime.
    event UpdatedRewardRatio(
        uint256 oldNumerator,
        uint256 newNumerator,
        uint256 oldDenominator,
        uint256 newDenominator
    );

    /// @dev Emitted when contract admin updates minimum staking amount.
    event UpdatedMinStakeAmount(uint256 oldAmount, uint256 newAmount);

    /**
     *  @notice Staker Info.
     *
     *  @param amountStaked             Total number of tokens staked by the staker.
     *
     *  @param timeOfLastUpdate         Last reward-update timestamp.
     *
     *  @param unclaimedRewards         Rewards accumulated but not claimed by user yet.
     *
     *  @param conditionIdOflastUpdate  Condition-Id when rewards were last updated for user.
     */
    struct Staker {
        uint256 amountStaked;
        uint256 timeOfLastUpdate;
        uint256 unclaimedRewards;
        uint256 conditionIdOflastUpdate;
    }

    /**
     *  @notice Staking Condition.
     *
     *  @param timeUnit                 Unit of time specified in number of seconds. Can be set as 1 seconds, 1 days, 1 hours, etc.
     *
     *  @param rewardRatioNumerator     Rewards ratio is the number of reward tokens for a number of staked tokens,
     *                                  per unit of time.
     *
     *  @param rewardRatioDenominator   Rewards ratio is the number of reward tokens for a number of staked tokens,
     *                                  per unit of time.
     *
     *  @param startTimestamp           Condition start timestamp.
     *
     *  @param endTimestamp             Condition end timestamp.
     */
    struct StakingCondition {
        uint256 timeUnit;
        uint256 rewardRatioNumerator;
        uint256 rewardRatioDenominator;
        uint256 startTimestamp;
        uint256 endTimestamp;
    }

    /**
     *  @notice Stake ERC721 Tokens.
     *
     *  @param amount    Amount to stake.
     */
    function stake(uint256 amount) external payable;

    /**
     *  @notice Withdraw staked tokens.
     *
     *  @param amount    Amount to withdraw.
     */
    function withdraw(uint256 amount) external;

    /**
     *  @notice Claim accumulated rewards.
     *
     */
    function claimRewards() external;

    /**
     *  @notice View amount staked and total rewards for a user.
     *
     *  @param staker    Address for which to calculated rewards.
     */
    function getStakeInfo(address staker) external view returns (uint256 _tokensStaked, uint256 _rewards);
}

// File: contracts/interfaces/IWETH.sol



// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.0;

interface IWETH {
    function deposit() external payable;

    function withdraw(uint256 amount) external;

    function transfer(address to, uint256 value) external returns (bool);
}

// File: contracts/interfaces/staking/ITokenStake.sol



// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.11;

/**
 *  Thirdweb's TokenStake smart contract allows users to stake their ERC-20 Tokens
 *  and earn rewards in form of a different ERC-20 token.
 *
 *  note:
 *  - Reward token and staking token can't be changed after deployment.
 *    Reward token contract can't be same as the staking token contract.
 *
 *  - ERC20 tokens from only the specified contract can be staked.
 *
 *  - All token transfers require approval on their respective token-contracts.
 *
 *  - Admin must deposit reward tokens using the `depositRewardTokens` function only.
 *    Any direct transfers may cause unintended consequences, such as locking of tokens.
 *
 *  - Users must stake tokens using the `stake` function only.
 *    Any direct transfers may cause unintended consequences, such as locking of tokens.
 */

interface ITokenStake {
    /// @dev Emitted when contract admin withdraws reward tokens.
    event RewardTokensWithdrawnByAdmin(uint256 _amount);

    /// @dev Emitted when contract admin deposits reward tokens.
    event RewardTokensDepositedByAdmin(uint256 _amount);

    /**
     *  @notice Lets a contract admin (account with `DEFAULT_ADMIN_ROLE`) deposit reward-tokens.
     *
     *          note: Tokens should be approved on the reward-token contract before depositing.
     *
     *  @param _amount     Amount of tokens to deposit.
     */
    function depositRewardTokens(uint256 _amount) external payable;

    /**
     *  @notice Lets a contract admin (account with `DEFAULT_ADMIN_ROLE`) withdraw reward-tokens.
     *          Useful for removing excess balance, thus preventing locking of tokens.
     *
     *  @param _amount     Amount of tokens to deposit.
     */
    function withdrawRewardTokens(uint256 _amount) external;
}

// File: contracts/lib/CurrencyTransferLib.sol



// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.0;

// Helper interfaces
import { IWETH } from "../interfaces/IWETH.sol";

import "../openzeppelin-presets/token/ERC20/utils/SafeERC20.sol";

library CurrencyTransferLib {
    using SafeERC20 for IERC20;

    /// @dev The address interpreted as native token of the chain.
    address public constant NATIVE_TOKEN = 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE;

    /// @dev Transfers a given amount of currency.
    function transferCurrency(
        address _currency,
        address _from,
        address _to,
        uint256 _amount
    ) internal {
        if (_amount == 0) {
            return;
        }

        if (_currency == NATIVE_TOKEN) {
            safeTransferNativeToken(_to, _amount);
        } else {
            safeTransferERC20(_currency, _from, _to, _amount);
        }
    }

    /// @dev Transfers a given amount of currency. (With native token wrapping)
    function transferCurrencyWithWrapper(
        address _currency,
        address _from,
        address _to,
        uint256 _amount,
        address _nativeTokenWrapper
    ) internal {
        if (_amount == 0) {
            return;
        }

        if (_currency == NATIVE_TOKEN) {
            if (_from == address(this)) {
                // withdraw from weth then transfer withdrawn native token to recipient
                IWETH(_nativeTokenWrapper).withdraw(_amount);
                safeTransferNativeTokenWithWrapper(_to, _amount, _nativeTokenWrapper);
            } else if (_to == address(this)) {
                // store native currency in weth
                require(_amount == msg.value, "msg.value != amount");
                IWETH(_nativeTokenWrapper).deposit{ value: _amount }();
            } else {
                safeTransferNativeTokenWithWrapper(_to, _amount, _nativeTokenWrapper);
            }
        } else {
            safeTransferERC20(_currency, _from, _to, _amount);
        }
    }

    /// @dev Transfer `amount` of ERC20 token from `from` to `to`.
    function safeTransferERC20(
        address _currency,
        address _from,
        address _to,
        uint256 _amount
    ) internal {
        if (_from == _to) {
            return;
        }

        if (_from == address(this)) {
            IERC20(_currency).safeTransfer(_to, _amount);
        } else {
            IERC20(_currency).safeTransferFrom(_from, _to, _amount);
        }
    }

    /// @dev Transfers `amount` of native token to `to`.
    function safeTransferNativeToken(address to, uint256 value) internal {
        // solhint-disable avoid-low-level-calls
        // slither-disable-next-line low-level-calls
        (bool success, ) = to.call{ value: value }("");
        require(success, "native token transfer failed");
    }

    /// @dev Transfers `amount` of native token to `to`. (With native token wrapping)
    function safeTransferNativeTokenWithWrapper(
        address to,
        uint256 value,
        address _nativeTokenWrapper
    ) internal {
        // solhint-disable avoid-low-level-calls
        // slither-disable-next-line low-level-calls
        (bool success, ) = to.call{ value: value }("");
        if (!success) {
            IWETH(_nativeTokenWrapper).deposit{ value: value }();
            IERC20(_nativeTokenWrapper).safeTransfer(to, value);
        }
    }
}

// File: contracts/lib/TWAddress.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (utils/Address.sol)

pragma solidity ^0.8.0;

/**
 * @dev Collection of functions related to the address type
 */
library TWAddress {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 0;
    }

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

        (bool success, ) = recipient.call{ value: amount }("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

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

        (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");

        (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");

        (bool success, bytes memory returndata) = target.delegatecall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

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

                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// File: contracts/lib/TWStrings.sol



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

pragma solidity ^0.8.0;

/**
 * @dev String operations.
 */
library TWStrings {
    bytes16 private constant _HEX_SYMBOLS = "0123456789abcdef";

    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        // Inspired by OraclizeAPI's implementation - MIT licence
        // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol

        if (value == 0) {
            return "0";
        }
        uint256 temp = value;
        uint256 digits;
        while (temp != 0) {
            digits++;
            temp /= 10;
        }
        bytes memory buffer = new bytes(digits);
        while (value != 0) {
            digits -= 1;
            buffer[digits] = bytes1(uint8(48 + uint256(value % 10)));
            value /= 10;
        }
        return string(buffer);
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        if (value == 0) {
            return "0x00";
        }
        uint256 temp = value;
        uint256 length = 0;
        while (temp != 0) {
            length++;
            temp >>= 8;
        }
        return toHexString(value, length);
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
            buffer[i] = _HEX_SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }
}

// File: contracts/openzeppelin-presets/metatx/ERC2771ContextUpgradeable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.0 (metatx/ERC2771Context.sol)

pragma solidity ^0.8.11;

import "@openzeppelin/contracts-upgradeable/utils/ContextUpgradeable.sol";
import "@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol";

/**
 * @dev Context variant with ERC2771 support.
 */
abstract contract ERC2771ContextUpgradeable is Initializable, ContextUpgradeable {
    mapping(address => bool) private _trustedForwarder;

    function __ERC2771Context_init(address[] memory trustedForwarder) internal onlyInitializing {
        __Context_init_unchained();
        __ERC2771Context_init_unchained(trustedForwarder);
    }

    function __ERC2771Context_init_unchained(address[] memory trustedForwarder) internal onlyInitializing {
        for (uint256 i = 0; i < trustedForwarder.length; i++) {
            _trustedForwarder[trustedForwarder[i]] = true;
        }
    }

    function isTrustedForwarder(address forwarder) public view virtual returns (bool) {
        return _trustedForwarder[forwarder];
    }

    function _msgSender() internal view virtual override returns (address sender) {
        if (isTrustedForwarder(msg.sender)) {
            // The assembly code is more direct than the Solidity version using `abi.decode`.
            assembly {
                sender := shr(96, calldataload(sub(calldatasize(), 20)))
            }
        } else {
            return super._msgSender();
        }
    }

    function _msgData() internal view virtual override returns (bytes calldata) {
        if (isTrustedForwarder(msg.sender)) {
            return msg.data[:msg.data.length - 20];
        } else {
            return super._msgData();
        }
    }

    uint256[49] private __gap;
}

// File: contracts/openzeppelin-presets/token/ERC20/utils/SafeERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.0;

import "../../../../eip/interface/IERC20.sol";
import "../../../../lib/TWAddress.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 TWAddress for address;

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

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

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

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

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

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

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

// File: contracts/openzeppelin-presets/utils/math/SafeMath.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (utils/math/SafeMath.sol)

pragma solidity ^0.8.0;

// CAUTION
// This version of SafeMath should only be used with Solidity 0.8 or later,
// because it relies on the compiler's built in overflow checks.

/**
 * @dev Wrappers over Solidity's arithmetic operations.
 *
 * NOTE: `SafeMath` is generally not needed starting with Solidity 0.8, since the compiler
 * now has built in overflow checking.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            uint256 c = a + b;
            if (c < a) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b > a) return (false, 0);
            return (true, a - b);
        }
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            // 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 (true, 0);
            uint256 c = a * b;
            if (c / a != b) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the division of two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a / b);
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a % b);
        }
    }

    /**
     * @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) {
        return a + b;
    }

    /**
     * @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 a - b;
    }

    /**
     * @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) {
        return a * b;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator.
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting 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 a % b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {trySub}.
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b <= a, errorMessage);
            return a - b;
        }
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting 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.
     */
    function div(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a / b;
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting with custom message when dividing by zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryMod}.
     *
     * 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,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a % b;
        }
    }
}

// File: contracts/staking/TokenStake.sol



// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.11;

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

// Meta transactions
import "../openzeppelin-presets/metatx/ERC2771ContextUpgradeable.sol";

// Utils
import "@openzeppelin/contracts-upgradeable/utils/MulticallUpgradeable.sol";
import { CurrencyTransferLib } from "../lib/CurrencyTransferLib.sol";
import "../eip/interface/IERC20Metadata.sol";

//  ==========  Features    ==========

import "../extension/ContractMetadata.sol";
import "../extension/PermissionsEnumerable.sol";
import { Staking20Upgradeable } from "../extension/Staking20Upgradeable.sol";
import "../interfaces/staking/ITokenStake.sol";

contract TokenStake is
    Initializable,
    ContractMetadata,
    PermissionsEnumerable,
    ERC2771ContextUpgradeable,
    MulticallUpgradeable,
    Staking20Upgradeable,
    ITokenStake
{
    bytes32 private constant MODULE_TYPE = bytes32("TokenStake");
    uint256 private constant VERSION = 1;

    /// @dev ERC20 Reward Token address. See {_mintRewards} below.
    address public rewardToken;

    /// @dev Total amount of reward tokens in the contract.
    uint256 private rewardTokenBalance;

    constructor(address _nativeTokenWrapper) initializer Staking20Upgradeable(_nativeTokenWrapper) {}

    /// @dev Initiliazes the contract, like a constructor.
    function initialize(
        address _defaultAdmin,
        string memory _contractURI,
        address[] memory _trustedForwarders,
        address _rewardToken,
        address _stakingToken,
        uint256 _timeUnit,
        uint256 _rewardRatioNumerator,
        uint256 _rewardRatioDenominator
    ) external initializer {
        __ERC2771Context_init_unchained(_trustedForwarders);

        require(_rewardToken != _stakingToken, "Reward Token and Staking Token can't be same.");
        rewardToken = _rewardToken;

        uint256 _stakingTokenDecimals = _stakingToken == CurrencyTransferLib.NATIVE_TOKEN
            ? 18
            : IERC20Metadata(_stakingToken).decimals();
        uint256 _rewardTokenDecimals = _rewardToken == CurrencyTransferLib.NATIVE_TOKEN
            ? 18
            : IERC20Metadata(_rewardToken).decimals();

        __Staking20_init(_stakingToken, _stakingTokenDecimals, _rewardTokenDecimals);
        _setStakingCondition(_timeUnit, _rewardRatioNumerator, _rewardRatioDenominator);

        _setupContractURI(_contractURI);
        _setupRole(DEFAULT_ADMIN_ROLE, _defaultAdmin);
    }

    /// @dev Returns the module type of the contract.
    function contractType() external pure virtual returns (bytes32) {
        return MODULE_TYPE;
    }

    /// @dev Returns the version of the contract.
    function contractVersion() external pure virtual returns (uint8) {
        return uint8(VERSION);
    }

    /// @dev Lets the contract receive ether to unwrap native tokens.
    receive() external payable {
        require(msg.sender == nativeTokenWrapper, "caller not native token wrapper.");
    }

    /// @dev Admin deposits reward tokens.
    function depositRewardTokens(uint256 _amount) external payable nonReentrant {
        require(hasRole(DEFAULT_ADMIN_ROLE, _msgSender()), "Not authorized");

        address _rewardToken = rewardToken == CurrencyTransferLib.NATIVE_TOKEN ? nativeTokenWrapper : rewardToken;

        uint256 balanceBefore = IERC20(_rewardToken).balanceOf(address(this));
        CurrencyTransferLib.transferCurrencyWithWrapper(
            rewardToken,
            _msgSender(),
            address(this),
            _amount,
            nativeTokenWrapper
        );
        uint256 actualAmount = IERC20(_rewardToken).balanceOf(address(this)) - balanceBefore;

        rewardTokenBalance += actualAmount;

        emit RewardTokensDepositedByAdmin(actualAmount);
    }

    /// @dev Admin can withdraw excess reward tokens.
    function withdrawRewardTokens(uint256 _amount) external nonReentrant {
        require(hasRole(DEFAULT_ADMIN_ROLE, _msgSender()), "Not authorized");

        // to prevent locking of direct-transferred tokens
        rewardTokenBalance = _amount > rewardTokenBalance ? 0 : rewardTokenBalance - _amount;

        CurrencyTransferLib.transferCurrencyWithWrapper(
            rewardToken,
            address(this),
            _msgSender(),
            _amount,
            nativeTokenWrapper
        );

        // The withdrawal shouldn't reduce staking token balance. `>=` accounts for any accidental transfers.
        address _stakingToken = stakingToken == CurrencyTransferLib.NATIVE_TOKEN ? nativeTokenWrapper : stakingToken;
        require(
            IERC20(_stakingToken).balanceOf(address(this)) >= stakingTokenBalance,
            "Staking token balance reduced."
        );

        emit RewardTokensWithdrawnByAdmin(_amount);
    }

    /// @notice View total rewards available in the staking contract.
    function getRewardTokenBalance() external view override returns (uint256) {
        return rewardTokenBalance;
    }

    /*///////////////////////////////////////////////////////////////
                        Transfer Staking Rewards
    //////////////////////////////////////////////////////////////*/

    /// @dev Mint/Transfer ERC20 rewards to the staker.
    function _mintRewards(address _staker, uint256 _rewards) internal override {
        require(_rewards <= rewardTokenBalance, "Not enough reward tokens");
        rewardTokenBalance -= _rewards;
        CurrencyTransferLib.transferCurrencyWithWrapper(
            rewardToken,
            address(this),
            _staker,
            _rewards,
            nativeTokenWrapper
        );
    }

    /*///////////////////////////////////////////////////////////////
                        Internal functions
    //////////////////////////////////////////////////////////////*/

    /// @dev Returns whether staking related restrictions can be set in the given execution context.
    function _canSetStakeConditions() internal view override returns (bool) {
        return hasRole(DEFAULT_ADMIN_ROLE, _msgSender());
    }

    /// @dev Checks whether contract metadata can be set in the given execution context.
    function _canSetContractURI() internal view override returns (bool) {
        return hasRole(DEFAULT_ADMIN_ROLE, _msgSender());
    }

    /*///////////////////////////////////////////////////////////////
                            Miscellaneous
    //////////////////////////////////////////////////////////////*/

    function _stakeMsgSender() internal view virtual override returns (address) {
        return _msgSender();
    }

    function _msgSender() internal view virtual override returns (address sender) {
        return ERC2771ContextUpgradeable._msgSender();
    }

    function _msgData() internal view virtual override returns (bytes calldata) {
        return ERC2771ContextUpgradeable._msgData();
    }
}

// File: node_modules/@openzeppelin/contracts-upgradeable/proxy/utils/Initializable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (proxy/utils/Initializable.sol)

pragma solidity ^0.8.2;

import "../../utils/AddressUpgradeable.sol";

/**
 * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
 * behind a proxy. Since proxied contracts do not make use of a constructor, it's common to move constructor logic to an
 * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
 * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
 *
 * The initialization functions use a version number. Once a version number is used, it is consumed and cannot be
 * reused. This mechanism prevents re-execution of each "step" but allows the creation of new initialization steps in
 * case an upgrade adds a module that needs to be initialized.
 *
 * For example:
 *
 * [.hljs-theme-light.nopadding]
 * ```
 * contract MyToken is ERC20Upgradeable {
 *     function initialize() initializer public {
 *         __ERC20_init("MyToken", "MTK");
 *     }
 * }
 * contract MyTokenV2 is MyToken, ERC20PermitUpgradeable {
 *     function initializeV2() reinitializer(2) public {
 *         __ERC20Permit_init("MyToken");
 *     }
 * }
 * ```
 *
 * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
 * possible by providing the encoded function call as the `_data` argument to {ERC1967Proxy-constructor}.
 *
 * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
 * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
 *
 * [CAUTION]
 * ====
 * Avoid leaving a contract uninitialized.
 *
 * An uninitialized contract can be taken over by an attacker. This applies to both a proxy and its implementation
 * contract, which may impact the proxy. To prevent the implementation contract from being used, you should invoke
 * the {_disableInitializers} function in the constructor to automatically lock it when it is deployed:
 *
 * [.hljs-theme-light.nopadding]
 * ```
 * /// @custom:oz-upgrades-unsafe-allow constructor
 * constructor() {
 *     _disableInitializers();
 * }
 * ```
 * ====
 */
abstract contract Initializable {
    /**
     * @dev Indicates that the contract has been initialized.
     * @custom:oz-retyped-from bool
     */
    uint8 private _initialized;

    /**
     * @dev Indicates that the contract is in the process of being initialized.
     */
    bool private _initializing;

    /**
     * @dev Triggered when the contract has been initialized or reinitialized.
     */
    event Initialized(uint8 version);

    /**
     * @dev A modifier that defines a protected initializer function that can be invoked at most once. In its scope,
     * `onlyInitializing` functions can be used to initialize parent contracts. Equivalent to `reinitializer(1)`.
     */
    modifier initializer() {
        bool isTopLevelCall = !_initializing;
        require(
            (isTopLevelCall && _initialized < 1) || (!AddressUpgradeable.isContract(address(this)) && _initialized == 1),
            "Initializable: contract is already initialized"
        );
        _initialized = 1;
        if (isTopLevelCall) {
            _initializing = true;
        }
        _;
        if (isTopLevelCall) {
            _initializing = false;
            emit Initialized(1);
        }
    }

    /**
     * @dev A modifier that defines a protected reinitializer function that can be invoked at most once, and only if the
     * contract hasn't been initialized to a greater version before. In its scope, `onlyInitializing` functions can be
     * used to initialize parent contracts.
     *
     * `initializer` is equivalent to `reinitializer(1)`, so a reinitializer may be used after the original
     * initialization step. This is essential to configure modules that are added through upgrades and that require
     * initialization.
     *
     * Note that versions can jump in increments greater than 1; this implies that if multiple reinitializers coexist in
     * a contract, executing them in the right order is up to the developer or operator.
     */
    modifier reinitializer(uint8 version) {
        require(!_initializing && _initialized < version, "Initializable: contract is already initialized");
        _initialized = version;
        _initializing = true;
        _;
        _initializing = false;
        emit Initialized(version);
    }

    /**
     * @dev Modifier to protect an initialization function so that it can only be invoked by functions with the
     * {initializer} and {reinitializer} modifiers, directly or indirectly.
     */
    modifier onlyInitializing() {
        require(_initializing, "Initializable: contract is not initializing");
        _;
    }

    /**
     * @dev Locks the contract, preventing any future reinitialization. This cannot be part of an initializer call.
     * Calling this in the constructor of a contract will prevent that contract from being initialized or reinitialized
     * to any version. It is recommended to use this to lock implementation contracts that are designed to be called
     * through proxies.
     */
    function _disableInitializers() internal virtual {
        require(!_initializing, "Initializable: contract is initializing");
        if (_initialized < type(uint8).max) {
            _initialized = type(uint8).max;
            emit Initialized(type(uint8).max);
        }
    }
}

// File: node_modules/@openzeppelin/contracts-upgradeable/security/ReentrancyGuardUpgradeable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (security/ReentrancyGuard.sol)

pragma solidity ^0.8.0;
import "../proxy/utils/Initializable.sol";

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
abstract contract ReentrancyGuardUpgradeable is Initializable {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant _NOT_ENTERED = 1;
    uint256 private constant _ENTERED = 2;

    uint256 private _status;

    function __ReentrancyGuard_init() internal onlyInitializing {
        __ReentrancyGuard_init_unchained();
    }

    function __ReentrancyGuard_init_unchained() internal onlyInitializing {
        _status = _NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and making it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_status != _ENTERED, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _status = _ENTERED;

        _;

        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = _NOT_ENTERED;
    }

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[49] private __gap;
}

// File: node_modules/@openzeppelin/contracts-upgradeable/utils/AddressUpgradeable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @dev Collection of functions related to the address type
 */
library AddressUpgradeable {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 0;
    }

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

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

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

        (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");

        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verifies that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly
                /// @solidity memory-safe-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// File: node_modules/@openzeppelin/contracts-upgradeable/utils/ContextUpgradeable.sol



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

pragma solidity ^0.8.0;
import "../proxy/utils/Initializable.sol";

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

    function __Context_init_unchained() internal onlyInitializing {
    }
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[50] private __gap;
}

// File: node_modules/@openzeppelin/contracts-upgradeable/utils/MulticallUpgradeable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.5.0) (utils/Multicall.sol)

pragma solidity ^0.8.0;

import "./AddressUpgradeable.sol";
import "../proxy/utils/Initializable.sol";

/**
 * @dev Provides a function to batch together multiple calls in a single external call.
 *
 * _Available since v4.1._
 */
abstract contract MulticallUpgradeable is Initializable {
    function __Multicall_init() internal onlyInitializing {
    }

    function __Multicall_init_unchained() internal onlyInitializing {
    }
    /**
     * @dev Receives and executes a batch of function calls on this contract.
     */
    function multicall(bytes[] calldata data) external virtual returns (bytes[] memory results) {
        results = new bytes[](data.length);
        for (uint256 i = 0; i < data.length; i++) {
            results[i] = _functionDelegateCall(address(this), data[i]);
        }
        return results;
    }

    /**
     * @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) private returns (bytes memory) {
        require(AddressUpgradeable.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 AddressUpgradeable.verifyCallResult(success, returndata, "Address: low-level delegate call failed");
    }

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[50] private __gap;
}

// File: node_modules/@openzeppelin/contracts/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

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

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

    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

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

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

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

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

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