// File: contracts/boardoom/core/VaultBoardroom.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import {IERC20} from '@openzeppelin/contracts/contracts/token/ERC20/IERC20.sol';
import {IVault} from '../../interfaces/IVault.sol';
import {SafeMath} from '@openzeppelin/contracts/contracts/math/SafeMath.sol';
import {ContractGuard} from '../../utils/ContractGuard.sol';
import {BaseBoardroom} from './BaseBoardroom.sol';

// import 'hardhat/console.sol';

contract VaultBoardroom is ContractGuard, BaseBoardroom {
    using SafeMath for uint256;

    // The vault which has state of the stakes.
    IVault public vault;
    uint256 public currentEpoch = 1;

    mapping(address => mapping(uint256 => BondingSnapshot))
        public bondingHistory;

    mapping(address => mapping(uint256 => uint256)) directorBalanceForEpoch;
    mapping(address => uint256) balanceCurrentEpoch;
    mapping(address => uint256) balanceLastEpoch;
    mapping(address => uint256) balanceBeforeLaunch;

    modifier directorExists {
        require(
            vault.balanceOf(msg.sender) > 0,
            'Boardroom: The director does not exist'
        );
        _;
    }

    modifier onlyVault {
        require(msg.sender == address(vault), 'Boardroom: not vault');
        _;
    }

    constructor(
        IERC20 token_,
        IVault vault_,
        address owner,
        address operator
    ) BaseBoardroom(token_) {
        vault = vault_;

        BoardSnapshot memory genesisSnapshot =
            BoardSnapshot({
                number: block.number,
                time: 0,
                rewardReceived: 0,
                rewardPerShare: 0
            });
        boardHistory.push(genesisSnapshot);

        transferOperator(operator);
        transferOwnership(owner);
    }

    function getBoardhistory(uint256 i)
        public
        view
        returns (BoardSnapshot memory)
    {
        return boardHistory[i];
    }

    function getBondingHistory(address who, uint256 epoch)
        public
        view
        returns (BondingSnapshot memory)
    {
        return bondingHistory[who][epoch];
    }

    // returns the balance as per the last epoch; if the user deposits/withdraws
    // in the current epoch, this value will not change unless another epoch passes
    function getBalanceFromLastEpoch(address who)
        public
        view
        returns (uint256)
    {
        // console.log('getBalanceFromLastEpoch who %s', who);
        // console.log('getBalanceFromLastEpoch currentEpoch %s', currentEpoch);
        if (currentEpoch == 1) return 0;

        // console.log(
        //     'getBalanceFromLastEpoch balanceLastEpoch[who] %s',
        //     balanceLastEpoch[who]
        // );
        // console.log(
        //     'getBalanceFromLastEpoch balanceCurrentEpoch[who] %s',
        //     balanceCurrentEpoch[who]
        // );

        if (balanceCurrentEpoch[who] == 0) {
            // console.log(
            //     'getBalanceFromLastEpoch balanceOf(who) %s',
            //     balanceOf(who)
            // );
            return balanceOf(who);
        }

        uint256 currentBalance =
            getBondingHistory(who, balanceCurrentEpoch[who]).balance;

        if (balanceCurrentEpoch[who] == currentEpoch) {
            // if boardroom was disconnected before then just return the old balance
            if (balanceLastEpoch[who] == 0) return balanceBeforeLaunch[who];
            return getBondingHistory(who, balanceLastEpoch[who]).balance;
        }

        if (balanceCurrentEpoch[who] < currentEpoch) {
            return currentBalance;
        }

        return 0;
    }

    function claimAndReinvestReward(IVault _vault) external virtual {
        uint256 reward = _claimReward(msg.sender);
        _vault.bondFor(msg.sender, reward);
    }

    function rewardPerShare() public view override returns (uint256) {
        return getLatestSnapshot().rewardPerShare;
    }

    function balanceOf(address who) public view returns (uint256) {
        uint256 unbondingAmount = vault.getStakedAmount(who);
        return vault.balanceOf(who).sub(unbondingAmount);
    }

    function earned(address director)
        public
        view
        virtual
        override
        returns (uint256)
    {
        uint256 latestRPS = getLatestSnapshot().rewardPerShare;
        uint256 storedRPS = getLastSnapshotOf(director).rewardPerShare;

        return
            getBalanceFromLastEpoch(director)
                .mul(latestRPS.sub(storedRPS))
                .div(1e18)
                .add(directors[director].rewardEarnedCurrEpoch);
    }

    function claimReward()
        public
        virtual
        override
        directorExists
        returns (uint256)
    {
        return _claimReward(msg.sender);
    }

    function allocateSeigniorage(uint256 amount)
        external
        override
        onlyOneBlock
        onlyOperator
    {
        require(amount > 0, 'Boardroom: Cannot allocate 0');

        uint256 totalSupply = vault.totalBondedSupply();

        // 'Boardroom: Cannot allocate when totalSupply is 0'
        if (totalSupply == 0) return;

        // Create & add new snapshot
        uint256 prevRPS = getLatestSnapshot().rewardPerShare;
        uint256 nextRPS = prevRPS.add(amount.mul(1e18).div(totalSupply));

        BoardSnapshot memory snap =
            BoardSnapshot({
                number: block.number,
                time: block.timestamp,
                rewardReceived: amount,
                rewardPerShare: nextRPS
            });
        boardHistory.push(snap);

        // console.log('allocateSeigniorage totalSupply: %s', totalSupply);
        // console.log('allocateSeigniorage time: %s', block.timestamp);
        // console.log('allocateSeigniorage rewardReceived: %s', amount);
        // console.log('allocateSeigniorage rewardPerShare: %s', nextRPS);

        token.transferFrom(msg.sender, address(this), amount);
        currentEpoch = currentEpoch.add(1);
        emit RewardAdded(msg.sender, amount);
    }

    function updateReward(address director)
        external
        virtual
        override
        onlyVault
    {
        _updateBalance(director);
    }

    function _claimReward(address who) internal returns (uint256) {
        _updateReward(who);

        uint256 reward = directors[who].rewardEarnedCurrEpoch;

        if (reward > 0) {
            directors[who].rewardEarnedCurrEpoch = 0;
            token.transfer(who, reward);
            emit RewardPaid(who, reward);

            if (balanceLastEpoch[who] == 0) {
                balanceBeforeLaunch[who] = balanceOf(who);
            }
        }

        return reward;
    }

    function setVault(IVault _vault) external onlyOwner {
        vault = _vault;
    }

    function _updateReward(address director) internal {
        Boardseat memory seat = directors[director];
        seat.rewardEarnedCurrEpoch = earned(director);
        seat.lastSnapshotIndex = latestSnapshotIndex();
        directors[director] = seat;
    }

    function _updateBalance(address who) internal {
        // console.log('updating balance for director at epoch: %s', currentEpoch);

        BondingSnapshot memory snap =
            BondingSnapshot({
                epoch: currentEpoch,
                when: block.timestamp,
                balance: balanceOf(who)
            });

        bondingHistory[who][currentEpoch] = snap;

        // update epoch counters if they need updating
        if (balanceCurrentEpoch[who] != currentEpoch) {
            balanceLastEpoch[who] = balanceCurrentEpoch[who];
            balanceCurrentEpoch[who] = currentEpoch;
        }

        // if (balanceLastEpoch[who] == 0) {
        //     require(
        //         earned(who) == 0,
        //         'Claim rewards once before depositing again'
        //     );
        // }

        if (balanceLastEpoch[who] == 0) {
            balanceLastEpoch[who] = 1;
        }

        _updateReward(who);
    }
}

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



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

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

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

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

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

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

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

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

// File: contracts/interfaces/IVault.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

interface IVault {
    function totalSupply() external view returns (uint256);

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

    function totalBondedSupply() external view returns (uint256);

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

    function bond(uint256 amount) external;

    function bondFor(address who, uint256 amount) external;

    function unbond(uint256 amount) external;

    function withdraw() external;

    function getStakedAmount(address who) external view returns (uint256);
}

// File: @openzeppelin/contracts/contracts/math/SafeMath.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations.
 */
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 substraction 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. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * 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/utils/ContractGuard.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

contract ContractGuard {
    mapping(uint256 => mapping(address => bool)) private _status;

    function checkSameOriginReentranted() internal view returns (bool) {
        return _status[block.number][tx.origin];
    }

    function checkSameSenderReentranted() internal view returns (bool) {
        return _status[block.number][msg.sender];
    }

    modifier onlyOneBlock() {
        require(
            !checkSameOriginReentranted(),
            'ContractGuard: one block, one function'
        );
        require(
            !checkSameSenderReentranted(),
            'ContractGuard: one block, one function'
        );

        _;

        _status[block.number][tx.origin] = true;
        _status[block.number][msg.sender] = true;
    }
}

// File: contracts/boardoom/core/BaseBoardroom.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import {IERC20} from '@openzeppelin/contracts/contracts/token/ERC20/IERC20.sol';
import {IVault} from '../../interfaces/IVault.sol';
import {SafeMath} from '@openzeppelin/contracts/contracts/math/SafeMath.sol';
import {Operator} from '../../owner/Operator.sol';
import {IBoardroom} from '../../interfaces/IBoardroom.sol';

abstract contract BaseBoardroom is Operator, IBoardroom {
    using SafeMath for uint256;

    IERC20 public token;

    BoardSnapshot[] public boardHistory;
    mapping(address => Boardseat) public directors;

    event RewardPaid(address indexed user, uint256 reward);
    event RewardAdded(address indexed user, uint256 reward);

    constructor(IERC20 token_) {
        token = token_;
    }

    function getDirector(address who)
        external
        view
        override
        returns (Boardseat memory)
    {
        return directors[who];
    }

    function getLastSnapshotIndexOf(address director)
        external
        view
        override
        returns (uint256)
    {
        return directors[director].lastSnapshotIndex;
    }

    function getLastSnapshotOf(address director)
        public
        view
        returns (BoardSnapshot memory)
    {
        return boardHistory[directors[director].lastSnapshotIndex];
    }

    function latestSnapshotIndex() public view returns (uint256) {
        return boardHistory.length.sub(1);
    }

    function getLatestSnapshot() public view returns (BoardSnapshot memory) {
        return boardHistory[latestSnapshotIndex()];
    }

    function rewardPerShare() public view virtual returns (uint256) {
        return getLatestSnapshot().rewardPerShare;
    }

    function refundReward() external onlyOwner {
        token.transfer(msg.sender, token.balanceOf(address(this)));
    }
}

// File: contracts/owner/Operator.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import '@openzeppelin/contracts/contracts/GSN/Context.sol';
import '@openzeppelin/contracts/contracts/access/Ownable.sol';
import {IOperator} from '../interfaces/IOperator.sol';

abstract contract Operator is Context, Ownable, IOperator {
    address private _operator;

    event OperatorTransferred(
        address indexed previousOperator,
        address indexed newOperator
    );

    constructor() {
        _operator = _msgSender();

        emit OperatorTransferred(address(0), _operator);
    }

    function operator() public view override returns (address) {
        return _operator;
    }

    modifier onlyOperator() {
        require(
            _operator == msg.sender,
            'operator: caller is not the operator'
        );
        _;
    }

    function isOperator() public view override returns (bool) {
        return _msgSender() == _operator;
    }

    function transferOperator(address newOperator_) public override onlyOwner {
        _transferOperator(newOperator_);
    }

    function _transferOperator(address newOperator_) internal {
        require(
            newOperator_ != address(0),
            'operator: zero address given for new operator'
        );

        emit OperatorTransferred(address(0), newOperator_);

        _operator = newOperator_;
    }
}

// File: contracts/interfaces/IBoardroom.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import {IOperator} from './IOperator.sol';

interface IBoardroom is IOperator {
    struct Boardseat {
        uint256 rewardClaimed;
        uint256 lastRPS;
        uint256 firstRPS;
        uint256 lastBoardSnapshotIndex;
        // // Pending reward from the previous epochs.
        // uint256 rewardPending;
        // Total reward earned in this epoch.
        uint256 rewardEarnedCurrEpoch;
        // Last time reward was claimed(not bound by current epoch).
        uint256 lastClaimedOn;
        // // The reward claimed in vesting period of this epoch.
        // uint256 rewardClaimedCurrEpoch;
        // // Snapshot of boardroom state when last epoch claimed.
        uint256 lastSnapshotIndex;
        // // Rewards claimable now in the current/next claim.
        // uint256 rewardClaimableNow;
        // // keep track of the current rps
        // uint256 claimedRPS;
        bool isFirstVaultActivityBeforeFirstEpoch;
        uint256 firstEpochWhenDoingVaultActivity;
    }

    struct BoardSnapshot {
        // Block number when recording a snapshot.
        uint256 number;
        // Block timestamp when recording a snapshot.
        uint256 time;
        // Amount of funds received.
        uint256 rewardReceived;
        // Equivalent amount per share staked.
        uint256 rewardPerShare;
    }

    struct BondingSnapshot {
        uint256 epoch;
        // Time when first bonding was made.
        uint256 when;
        // The snapshot index of when first bonded.
        uint256 balance;
    }

    // function updateReward(address director) external;

    function allocateSeigniorage(uint256 amount) external;

    function getDirector(address who) external view returns (Boardseat memory);

    function getLastSnapshotIndexOf(address director)
        external
        view
        returns (uint256);

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

    function claimReward() external returns (uint256);

    function updateReward(address director) external;
}

// File: @openzeppelin/contracts/contracts/GSN/Context.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

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

// File: @openzeppelin/contracts/contracts/access/Ownable.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

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

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

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor () {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }

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

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

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

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

// File: contracts/interfaces/IOperator.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

import {IEpoch} from './IEpoch.sol';

interface IOperator {
    function operator() external view returns (address);

    function isOperator() external view returns (bool);

    function transferOperator(address newOperator_) external;
}

// File: @openzeppelin/contracts/contracts/utils/Context.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

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

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

// File: contracts/interfaces/IEpoch.sol



// SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

interface IEpoch {
    function callable() external view returns (bool);

    function getLastEpoch() external view returns (uint256);

    function getCurrentEpoch() external view returns (uint256);

    function getNextEpoch() external view returns (uint256);

    function nextEpochPoint() external view returns (uint256);

    function getPeriod() external view returns (uint256);

    function getStartTime() external view returns (uint256);

    function setPeriod(uint256 _period) external;
}