// File: @openzeppelin/contracts/utils/Context.sol


pragma solidity >=0.6.0 <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 payable) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

// File: @openzeppelin/contracts/access/Ownable.sol


pragma solidity >=0.6.0 <0.8.0;

/**
 * @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 () internal {
        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: @openzeppelin/contracts/math/SafeMath.sol


pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        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) {
        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) {
        // 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) {
        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) {
        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) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");
        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b <= a, "SafeMath: subtraction overflow");
        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) {
        if (a == 0) return 0;
        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");
        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        require(b > 0, "SafeMath: division by zero");
        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) {
        require(b > 0, "SafeMath: modulo by zero");
        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) {
        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.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryDiv}.
     *
     * 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) {
        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) {
        require(b > 0, errorMessage);
        return a % b;
    }
}

// File: @openzeppelin/contracts/token/ERC20/IERC20.sol


pragma solidity >=0.6.0 <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: @api3-contracts/api3-token/contracts/interfaces/IApi3Token.sol

pragma solidity 0.6.12;



interface IApi3Token is IERC20 {
    event MinterStatusUpdated(
        address indexed minterAddress,
        bool minterStatus
        );

    event BurnerStatusUpdated(
        address indexed burnerAddress,
        bool burnerStatus
        );

    function updateMinterStatus(
        address minterAddress,
        bool minterStatus
        )
        external;

    function updateBurnerStatus(bool burnerStatus)
        external;

    function mint(
        address account,
        uint256 amount
        )
        external;

    function burn(uint256 amount)
        external;

    function getMinterStatus(address minterAddress)
        external
        view
        returns(bool minterStatus);

    function getBurnerStatus(address burnerAddress)
        external
        view
        returns(bool burnerStatus);
}

// File: contracts/interfaces/ITimelockManagerReversible.sol

pragma solidity 0.6.12;

interface ITimelockManagerReversible {

    event StoppedVesting(
        address recipient, 
        address destination, 
        uint256 amount
    );

    event TransferredAndLocked(
        address source,
        address indexed recipient,
        uint256 amount,
        uint256 releaseStart,
        uint256 releaseEnd
    );

    event Withdrawn(
        address indexed recipient, 
        uint256 amount
    );

    function stopVesting(
        address recipient, 
        address destination
    ) external;

    function transferAndLock(
        address source,
        address recipient,
        uint256 amount,
        uint256 releaseStart,
        uint256 releaseEnd
    ) external;

    function transferAndLockMultiple(
        address source,
        address[] calldata recipients,
        uint256[] calldata amounts,
        uint256[] calldata releaseStarts,
        uint256[] calldata releaseEnds
    ) external;

    function withdraw() external;

    function getWithdrawable(address recipient)
        external
        view
        returns (
            uint256 withdrawable
        );

    function getTimelock(address recipient)
        external
        view
        returns (
            uint256 totalAmount,
            uint256 remainingAmount,
            uint256 releaseStart,
            uint256 releaseEnd
        );

    function getRemainingAmount(address recipient)
        external
        view
        returns (
            uint256 remainingAmount
        );
}

// File: contracts/TimeLockManagerReversible.sol

pragma solidity 0.6.12;





/// @title Contract that the TimeLockManager Contract Owner uses to timelock API3 tokens
/// @notice The owner of TimelockManager can send tokens to
/// TimelockManager to timelock them. These tokens will then be vested to their
/// recipient linearly, starting from releaseStart and ending at releaseEnd of
/// the respective timelock.

contract TimelockManagerReversible is Ownable, ITimelockManagerReversible {
    using SafeMath for uint256;

    struct Timelock {
        uint256 totalAmount;
        uint256 remainingAmount;
        uint256 releaseStart;
        uint256 releaseEnd;
    }

    IApi3Token public immutable api3Token;
    mapping(address => Timelock) public timelocks;

    /// @param api3TokenAddress Address of the API3 token contract
    /// @param timelockManagerOwner Address that will receive the ownership of
    /// the TimelockManager contract
    constructor(
        address api3TokenAddress, 
        address timelockManagerOwner
        ) 
        public 
    {
        api3Token = IApi3Token(api3TokenAddress);
        transferOwnership(timelockManagerOwner);
    }

    /// @notice Called by the ContractOwner to stop the vesting of
    /// a recipient
    /// @param recipient Original recipient of tokens
    /// @param destination Destination of the excess tokens vested to the addresss
    function stopVesting(
        address recipient, 
        address destination
        )
        external
        override
        onlyOwner
        onlyIfRecipientHasRemainingTokens(recipient)
    {
        uint256 withdrawable = getWithdrawable(recipient);
        uint256 reclaimedTokens =
            timelocks[recipient].remainingAmount.sub(withdrawable);
        timelocks[recipient].remainingAmount = withdrawable;
        timelocks[recipient].releaseEnd = now;
        require(
            api3Token.transfer(destination, reclaimedTokens),
            "API3 token transfer failed"
        );
        emit StoppedVesting(recipient, destination, reclaimedTokens);
    }

    /// @notice Transfers API3 tokens to this contract and timelocks them
    /// @dev source needs to approve() this contract to transfer amount number
    /// of tokens beforehand.
    /// A recipient cannot have multiple timelocks.
    /// @param source Source of tokens
    /// @param recipient Recipient of tokens
    /// @param amount Amount of tokens
    /// @param releaseStart Start of release time
    /// @param releaseEnd End of release time
    function transferAndLock(
        address source,
        address recipient,
        uint256 amount,
        uint256 releaseStart,
        uint256 releaseEnd
        ) 
        public 
        override 
        onlyOwner
    {
        require(
            timelocks[recipient].remainingAmount == 0,
            "Recipient has remaining tokens"
        );
        require(amount != 0, "Amount cannot be 0");
        require(
            releaseEnd > releaseStart,
            "releaseEnd not larger than releaseStart"
        );
        timelocks[recipient] = Timelock({
            totalAmount: amount,
            remainingAmount: amount,
            releaseStart: releaseStart,
            releaseEnd: releaseEnd
        });
        require(
            api3Token.transferFrom(source, address(this), amount),
            "API3 token transferFrom failed"
        );
        emit TransferredAndLocked(
            source,
            recipient,
            amount,
            releaseStart,
            releaseEnd
        );
    }

    /// @notice Convenience function that calls transferAndLock() multiple times
    /// @dev source is expected to be a single address.
    /// source needs to approve() this contract to transfer the sum of the
    /// amounts of tokens to be transferred and locked.
    /// @param source Source of tokens
    /// @param recipients Array of recipients of tokens
    /// @param amounts Array of amounts of tokens
    /// @param releaseStarts Array of starts of release times
    /// @param releaseEnds Array of ends of release times
    function transferAndLockMultiple(
        address source,
        address[] calldata recipients,
        uint256[] calldata amounts,
        uint256[] calldata releaseStarts,
        uint256[] calldata releaseEnds
        ) 
        external 
        override 
        onlyOwner 
    {
        require(
            recipients.length == amounts.length &&
                recipients.length == releaseStarts.length &&
                recipients.length == releaseEnds.length,
            "Parameters are of unequal length"
        );
        require(recipients.length <= 30, "Parameters are longer than 30");
        for (uint256 ind = 0; ind < recipients.length; ind++) {
            transferAndLock(
                source,
                recipients[ind],
                amounts[ind],
                releaseStarts[ind],
                releaseEnds[ind]
            );
        }
    }

    /// @notice Used by the recipient to withdraw tokens
    function withdraw()
        external
        override
        onlyIfRecipientHasRemainingTokens(msg.sender)
    {
        address recipient = msg.sender;
        uint256 withdrawable = getWithdrawable(recipient);
        require(withdrawable != 0, "No withdrawable tokens yet");
        timelocks[recipient].remainingAmount = timelocks[recipient]
            .remainingAmount
            .sub(withdrawable);
        require(
            api3Token.transfer(recipient, withdrawable),
            "API3 token transfer failed"
        );
        emit Withdrawn(recipient, withdrawable);
    }

    /// @notice Returns the amount of tokens a recipient can currently withdraw
    /// @param recipient Address of the recipient
    /// @return withdrawable Amount of tokens withdrawable by the recipient
    function getWithdrawable(address recipient)
        public
        view
        override
        returns (uint256 withdrawable)
    {
        Timelock storage timelock = timelocks[recipient];
        uint256 unlocked = getUnlocked(recipient);
        uint256 withdrawn = timelock.totalAmount.sub(timelock.remainingAmount);
        withdrawable = unlocked.sub(withdrawn);
    }

    /// @notice Returns the amount of tokens that was unlocked for the
    /// recipient to date. Includes both withdrawn and non-withdrawn tokens.
    /// @param recipient Address of the recipient
    /// @return unlocked Amount of tokens unlocked for the recipient
    function getUnlocked(address recipient)
        private
        view
        returns (uint256 unlocked)
    {
        Timelock storage timelock = timelocks[recipient];
        if (now <= timelock.releaseStart) {
            unlocked = 0;
        } else if (now >= timelock.releaseEnd) {
            unlocked = timelock.totalAmount;
        } else {
            uint256 passedTime = now.sub(timelock.releaseStart);
            uint256 totalTime = timelock.releaseEnd.sub(timelock.releaseStart);
            unlocked = timelock.totalAmount.mul(passedTime).div(totalTime);
        }
    }

    /// @notice Returns the details of a timelock
    /// @param recipient Recipient of tokens
    /// @return totalAmount Total amount of tokens
    /// @return remainingAmount Remaining amount of tokens to be withdrawn
    /// @return releaseStart Release start time
    /// @return releaseEnd Release end time
    function getTimelock(address recipient)
        external
        view
        override
        returns (
            uint256 totalAmount,
            uint256 remainingAmount,
            uint256 releaseStart,
            uint256 releaseEnd
        )
    {
        Timelock storage timelock = timelocks[recipient];
        totalAmount = timelock.totalAmount;
        remainingAmount = timelock.remainingAmount;
        releaseStart = timelock.releaseStart;
        releaseEnd = timelock.releaseEnd;
    }

    /// @notice Returns remaining amount of a timelock
    /// @dev Provided separately to be used with Etherscan's "Read"
    /// functionality, in case getTimelock() output is too complicated for the
    /// user.
    /// @param recipient Recipient of tokens
    /// @return remainingAmount Remaining amount of tokens to be withdrawn
    function getRemainingAmount(address recipient)
        external
        view
        override
        returns (uint256 remainingAmount)
    {
        remainingAmount = timelocks[recipient].remainingAmount;
    }

    /// @dev Reverts if the recipient does not have remaining tokens
    modifier onlyIfRecipientHasRemainingTokens(address recipient) {
        require(
            timelocks[recipient].remainingAmount != 0,
            "Recipient does not have remaining tokens"
        );
        _;
    }
}