pragma solidity ^0.5.16;
pragma experimental ABIEncoderV2;

contract StrikeStakingProxyAdminStorage {
    /**
    * @notice Administrator for this contract
    */
    address public admin;

    /**
    * @notice Pending administrator for this contract
    */
    address public pendingAdmin;

    /**
    * @notice Active brains of StrikeStakingProxy
    */
    address public strikeStakingImplementation;

    /**
    * @notice Pending brains of StrikeStakingProxy
    */
    address public pendingStrikeStakingImplementation;
}

contract StrikeStakingG1Storage is StrikeStakingProxyAdminStorage {
}

// File: contracts/Staking/StrikeStakingProxy.sol

pragma solidity ^0.5.16;

/**
 * @title StrikeStakingProxy
 * @dev Storage for the strike staking is at this address, while execution is delegated to the `strikeStakingImplementation`.
 */
contract StrikeStakingProxy is StrikeStakingProxyAdminStorage {

    /**
      * @notice Emitted when pendingStrikeStakingImplementation is changed
      */
    event NewPendingImplementation(address oldPendingImplementation, address newPendingImplementation);

    /**
      * @notice Emitted when pendingStrikeStakingImplementation is accepted, which means strikeStaking implementation is updated
      */
    event NewImplementation(address oldImplementation, address newImplementation);

    /**
      * @notice Emitted when pendingAdmin is changed
      */
    event NewPendingAdmin(address oldPendingAdmin, address newPendingAdmin);

    /**
      * @notice Emitted when pendingAdmin is accepted, which means admin is updated
      */
    event NewAdmin(address oldAdmin, address newAdmin);

    constructor() public {
        // Set admin to caller
        admin = msg.sender;
    }

    /*** Admin Functions ***/
    function _setPendingImplementation(address newPendingImplementation) public {
        require(msg.sender == admin, "SET_PENDING_IMPLEMENTATION_OWNER_CHECK");

        address oldPendingImplementation = pendingStrikeStakingImplementation;

        pendingStrikeStakingImplementation = newPendingImplementation;

        emit NewPendingImplementation(oldPendingImplementation, pendingStrikeStakingImplementation);
    }

    /**
    * @notice Accepts new implementation of strikeStaking. msg.sender must be pendingImplementation
    * @dev Admin function for new implementation to accept it's role as implementation
    */
    function _acceptImplementation() public {
        // Check caller is pendingImplementation and pendingImplementation ≠ address(0)
        require(msg.sender == pendingStrikeStakingImplementation && pendingStrikeStakingImplementation != address(0), "ACCEPT_PENDING_IMPLEMENTATION_ADDRESS_CHECK");

        // Save current values for inclusion in log
        address oldImplementation = strikeStakingImplementation;
        address oldPendingImplementation = pendingStrikeStakingImplementation;

        strikeStakingImplementation = pendingStrikeStakingImplementation;

        pendingStrikeStakingImplementation = address(0);

        emit NewImplementation(oldImplementation, strikeStakingImplementation);
        emit NewPendingImplementation(oldPendingImplementation, pendingStrikeStakingImplementation);
    }

    /**
      * @notice Begins transfer of admin rights. The newPendingAdmin must call `_acceptAdmin` to finalize the transfer.
      * @dev Admin function to begin change of admin. The newPendingAdmin must call `_acceptAdmin` to finalize the transfer.
      * @param newPendingAdmin New pending admin.
      * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
      */
    function _setPendingAdmin(address newPendingAdmin) public {
        require(msg.sender == admin, "SET_PENDING_ADMIN_OWNER_CHECK");

        // Save current value, if any, for inclusion in log
        address oldPendingAdmin = pendingAdmin;

        // Store pendingAdmin with value newPendingAdmin
        pendingAdmin = newPendingAdmin;

        // Emit NewPendingAdmin(oldPendingAdmin, newPendingAdmin)
        emit NewPendingAdmin(oldPendingAdmin, newPendingAdmin);
    }

    /**
      * @notice Accepts transfer of admin rights. msg.sender must be pendingAdmin
      * @dev Admin function for pending admin to accept role and update admin
      * @return uint 0=success, otherwise a failure (see ErrorReporter.sol for details)
      */
    function _acceptAdmin() public {
        require(msg.sender == pendingAdmin && msg.sender != address(0), "ACCEPT_ADMIN_PENDING_ADMIN_CHECK");

        // Save current values for inclusion in log
        address oldAdmin = admin;
        address oldPendingAdmin = pendingAdmin;

        // Store admin with value pendingAdmin
        admin = pendingAdmin;

        // Clear the pending value
        pendingAdmin = address(0);

        emit NewAdmin(oldAdmin, admin);
        emit NewPendingAdmin(oldPendingAdmin, pendingAdmin);
    }

    /**
     * @dev Delegates execution to an implementation contract.
     * It returns to the external caller whatever the implementation returns
     * or forwards reverts.
     */
    function () external payable {
        // delegate all other functions to current implementation
        (bool success, ) = strikeStakingImplementation.delegatecall(msg.data);

        assembly {
              let free_mem_ptr := mload(0x40)
              returndatacopy(free_mem_ptr, 0, returndatasize)

              switch success
              case 0 { revert(free_mem_ptr, returndatasize) }
              default { return(free_mem_ptr, returndatasize) }
        }
    }
}

// File: contracts/Lib/GSN/Context.sol

pragma solidity ^0.5.0;

/*
 * @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.
 */
contract Context {
    // Empty internal constructor, to prevent people from mistakenly deploying
    // an instance of this contract, which should be used via inheritance.
    constructor () internal { }
    // solhint-disable-previous-line no-empty-blocks

    function _msgSender() internal view returns (address payable) {
        return msg.sender;
    }

    function _msgData() internal view returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

// File: contracts/Lib/token/ERC20/IERC20.sol

pragma solidity ^0.5.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP. Does not include
 * the optional functions; to access them see {ERC20Detailed}.
 */
interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

// File: contracts/Lib/math/SafeMath.sol

pragma solidity ^0.5.0;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when an
 * operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     * - Subtraction cannot overflow.
     *
     * _Available since v2.4.0._
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     *
     * _Available since v2.4.0._
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        // Solidity only automatically asserts when dividing by 0
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     * - The divisor cannot be zero.
     *
     * _Available since v2.4.0._
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

// File: contracts/Lib/utils/Address.sol

pragma solidity ^0.5.5;

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following 
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
        // for accounts without code, i.e. `keccak256('')`
        bytes32 codehash;
        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly { codehash := extcodehash(account) }
        return (codehash != accountHash && codehash != 0x0);
    }

    /**
     * @dev Converts an `address` into `address payable`. Note that this is
     * simply a type cast: the actual underlying value is not changed.
     *
     * _Available since v2.4.0._
     */
    function toPayable(address account) internal pure returns (address payable) {
        return address(uint160(account));
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     *
     * _Available since v2.4.0._
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        // solhint-disable-next-line avoid-call-value
        (bool success, ) = recipient.call.value(amount)("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }
}

// File: contracts/Lib/token/ERC20/SafeERC20.sol

pragma solidity ^0.5.0;



/**
 * @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 ERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using SafeMath for uint256;
    using Address for address;

    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    function safeApprove(IERC20 token, address spender, uint256 value) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        // solhint-disable-next-line max-line-length
        require((value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).add(value);
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
        callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves.

        // A Solidity high level call has three parts:
        //  1. The target address is checked to verify it contains contract code
        //  2. The call itself is made, and success asserted
        //  3. The return value is decoded, which in turn checks the size of the returned data.
        // solhint-disable-next-line max-line-length
        require(address(token).isContract(), "SafeERC20: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = address(token).call(data);
        require(success, "SafeERC20: low-level call failed");

        if (returndata.length > 0) { // Return data is optional
            // solhint-disable-next-line max-line-length
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

// File: contracts/Lib/math/Math.sol

pragma solidity ^0.5.0;

/**
 * @dev Standard math utilities missing in the Solidity language.
 */
library Math {
    /**
     * @dev Returns the largest of two numbers.
     */
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a >= b ? a : b;
    }

    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }

    /**
     * @dev Returns the average of two numbers. The result is rounded towards
     * zero.
     */
    function average(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b) / 2 can overflow, so we distribute
        return (a / 2) + (b / 2) + ((a % 2 + b % 2) / 2);
    }
}

// File: contracts/Staking/StrikeStaking.sol

// SPDX-License-Identifier: MIT

pragma solidity ^0.5.16;






// Based on EPS's & Geist's MultiFeeDistribution
contract StrikeStaking is StrikeStakingG1Storage {
    using SafeMath for uint256;
    using SafeERC20 for IERC20;

    modifier onlyOwner() {
        require(admin == msg.sender, "caller is not the admin");
        _;
    }

    function owner() public view returns(address) {
        return admin;
    }

    /* ========== STATE VARIABLES ========== */

    struct Reward {
        uint256 periodFinish;
        uint256 rewardRate;
        uint256 lastUpdateTime;
        uint256 rewardPerTokenStored;
    }
    struct Balances {
        uint256 total;
        uint256 unlocked;
        uint256 locked;
        uint256 earned;
    }
    struct LockedBalance {
        uint256 amount;
        uint256 unlockTime;
    }
    struct RewardData {
        address token;
        uint256 amount;
    }

    IERC20 public stakingToken;
    address[] public rewardTokens;
    mapping(address => Reward) public rewardData;

    // Duration that rewards are streamed over
    uint256 public constant rewardsDuration = 86400 * 14; // 2 weeks

    // Duration of lock/earned penalty period
    uint256 public constant lockDuration = rewardsDuration * 6; // 12 weeks

    // Duration of lock/earned group period
    uint256 public constant groupDuration = 86400 * 7; // 1 weeks

    // Addresses approved to call mint
    mapping(address => bool) public minters;
    address[] public mintersArray;

    // reward token -> distributor -> is approved to add rewards
    mapping(address => mapping(address => bool)) public rewardDistributors;

    // user -> reward token -> amount
    mapping(address => mapping(address => uint256)) public userRewardPerTokenPaid;
    mapping(address => mapping(address => uint256)) public rewards;

    uint256 public totalSupply;
    uint256 public lockedSupply;

    // Private mappings for balance data
    mapping(address => Balances) private balances;
    mapping(address => LockedBalance[]) private userLocks;
    mapping(address => LockedBalance[]) private userEarnings;

    bool private _notEntered;

    /**
      * @notice Emitted when pendingAdmin is changed
      */
    event NewPendingAdmin(address oldPendingAdmin, address newPendingAdmin);

    /**
      * @notice Emitted when pendingAdmin is accepted, which means admin is updated
      */
    event NewAdmin(address oldAdmin, address newAdmin);


    /**
     * @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 make it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        // On the first call to nonReentrant, _notEntered will be true
        require(_notEntered, "ReentrancyGuard: reentrant call");

        // Any calls to nonReentrant after this point will fail
        _notEntered = false;

        _;

        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _notEntered = true;
    }

    /* ========== CONSTRUCTOR ========== */

    constructor() public {
    }

    function initialize(
        address _stakingToken,
        address[] calldata _minters
    ) external {
        require(address(stakingToken) == address(0), "StrikeStaking:initialize: Already initialized");

        _notEntered = true;

        stakingToken = IERC20(_stakingToken);
        for (uint256 i; i < _minters.length; i++) {
            minters[_minters[i]] = true;
            mintersArray.push(_minters[i]);
        }
        // First reward MUST be the staking token or things will break
        // related to the 50% penalty and distribution to locked balances
        rewardTokens.push(_stakingToken);
        rewardData[_stakingToken].lastUpdateTime = block.timestamp;
        rewardData[_stakingToken].periodFinish = block.timestamp;
    }

    /* ========== ADMIN CONFIGURATION ========== */

    // Add a new reward token to be distributed to stakers
    function addReward(address _rewardsToken, address _distributor) public onlyOwner {
        require(rewardData[_rewardsToken].lastUpdateTime == 0, "MultiFeeDistribution::addReward: Invalid");
        rewardTokens.push(_rewardsToken);
        rewardData[_rewardsToken].lastUpdateTime = block.timestamp;
        rewardData[_rewardsToken].periodFinish = block.timestamp;
        rewardDistributors[_rewardsToken][_distributor] = true;
        emit RewardTokenAdded(_rewardsToken);
        emit RewardDistributorApproved(_rewardsToken, _distributor, true);
    }

    // Modify approval for an address to call notifyRewardAmount
    function approveRewardDistributor(
        address _rewardsToken,
        address _distributor,
        bool _approved
    ) external onlyOwner {
        require(rewardData[_rewardsToken].lastUpdateTime > 0, "MultiFeeDistribution::approveRewardDistributor: Invalid");
        rewardDistributors[_rewardsToken][_distributor] = _approved;
        emit RewardDistributorApproved(_rewardsToken, _distributor, _approved);
    }

    /* ========== VIEWS ========== */

    function _rewardPerToken(address _rewardsToken, uint256 _supply) internal view returns (uint256) {
        if (_supply == 0) {
            return rewardData[_rewardsToken].rewardPerTokenStored;
        }
        return
            rewardData[_rewardsToken].rewardPerTokenStored.add(
                lastTimeRewardApplicable(_rewardsToken).sub(rewardData[_rewardsToken].lastUpdateTime).mul(rewardData[_rewardsToken].rewardRate).mul(1e18).div(_supply)
            );
    }

    function _earned(
        address _user,
        address _rewardsToken,
        uint256 _balance,
        uint256 supply
    ) internal view returns (uint256) {
        return _balance.mul(_rewardPerToken(_rewardsToken, supply).sub(userRewardPerTokenPaid[_user][_rewardsToken])).div(1e18).add(rewards[_user][_rewardsToken]);
    }

    function lastTimeRewardApplicable(address _rewardsToken) public view returns (uint256) {
        return Math.min(block.timestamp, rewardData[_rewardsToken].periodFinish);
    }

    function rewardPerToken(address _rewardsToken) external view returns (uint256) {
        uint256 supply = _rewardsToken == address(stakingToken) ? lockedSupply : totalSupply;
        return _rewardPerToken(_rewardsToken, supply);
    }

    function getRewardForDuration(address _rewardsToken) external view returns (uint256) {
        return rewardData[_rewardsToken].rewardRate.mul(rewardsDuration);
    }

    // Address and claimable amount of all reward tokens for the given account
    function claimableRewards(address account) external view returns (RewardData[] memory _rewards) {
        _rewards = new RewardData[](rewardTokens.length);
        for (uint256 i = 0; i < _rewards.length; i++) {
            // If i == 0 this is the stakingReward, distribution is based on locked balances
            uint256 balance = i == 0 ? balances[account].locked : balances[account].total;
            uint256 supply = i == 0 ? lockedSupply : totalSupply;
            _rewards[i].token = rewardTokens[i];
            _rewards[i].amount = _earned(account, _rewards[i].token, balance, supply);
        }
        return _rewards;
    }

    // Total balance of an account, including unlocked, locked and earned tokens
    function totalBalance(address user) external view returns (uint256 amount) {
        return balances[user].total;
    }

    // Total withdrawable balance for an account to which no penalty is applied
    function unlockedBalance(address user) external view returns (uint256 amount) {
        amount = balances[user].unlocked;
        LockedBalance[] storage earnings = userEarnings[user];
        for (uint256 i = 0; i < earnings.length; i++) {
            if (earnings[i].unlockTime > block.timestamp) {
                break;
            }
            amount = amount.add(earnings[i].amount);
        }
        return amount;
    }

    // Information on the "earned" balances of a user
    // Earned balances may be withdrawn immediately for a 50% penalty
    function earnedBalances(address user) external view returns (uint256 total, LockedBalance[] memory earningsData) {
        LockedBalance[] storage earnings = userEarnings[user];
        uint256 idx;
        for (uint256 i = 0; i < earnings.length; i++) {
            if (earnings[i].unlockTime > block.timestamp) {
                if (idx == 0) {
                    earningsData = new LockedBalance[](earnings.length - i);
                }
                earningsData[idx] = earnings[i];
                idx++;
                total = total.add(earnings[i].amount);
            }
        }
        return (total, earningsData);
    }

    // Information on a user's locked balances
    function lockedBalances(address user)
        external
        view
        returns (
            uint256 total,
            uint256 unlockable,
            uint256 locked,
            LockedBalance[] memory lockData
        )
    {
        LockedBalance[] storage locks = userLocks[user];
        uint256 idx;
        for (uint256 i = 0; i < locks.length; i++) {
            if (locks[i].unlockTime > block.timestamp) {
                if (idx == 0) {
                    lockData = new LockedBalance[](locks.length - i);
                }
                lockData[idx] = locks[i];
                idx++;
                locked = locked.add(locks[i].amount);
            } else {
                unlockable = unlockable.add(locks[i].amount);
            }
        }
        return (balances[user].locked, unlockable, locked, lockData);
    }

    // Final balance received and penalty balance paid by user upon calling exit
    function withdrawableBalance(address user) public view returns (uint256 amount, uint256 penaltyAmount) {
        Balances storage bal = balances[user];
        uint256 amountWithoutPenalty;
        if (bal.earned > 0) {
            uint256 length = userEarnings[user].length;
            for (uint256 i = 0; i < length; i++) {
                uint256 earnedAmount = userEarnings[user][i].amount;
                if (earnedAmount == 0) continue;
                if (userEarnings[user][i].unlockTime > block.timestamp) {
                    break;
                }
                amountWithoutPenalty = amountWithoutPenalty.add(earnedAmount);
            }

            penaltyAmount = bal.earned.sub(amountWithoutPenalty).div(2);
        }
        amount = bal.unlocked.add(amountWithoutPenalty).add(penaltyAmount);
        return (amount, penaltyAmount);
    }

    /* ========== MUTATIVE FUNCTIONS ========== */

    // Stake tokens to receive rewards
    // Locked tokens cannot be withdrawn for lockDuration and are eligible to receive stakingReward rewards
    function stake(uint256 amount, bool lock) external nonReentrant updateReward(msg.sender) {
        require(amount > 0, "MultiFeeDistribution::stake: Cannot stake 0");
        require(lock == true, "Only lock enabled");
        totalSupply = totalSupply.add(amount);
        Balances storage bal = balances[msg.sender];
        bal.total = bal.total.add(amount);
        if (lock) {
            lockedSupply = lockedSupply.add(amount);
            bal.locked = bal.locked.add(amount);
            uint256 unlockTime = block.timestamp.div(groupDuration).mul(groupDuration).add(lockDuration);
            uint256 idx = userLocks[msg.sender].length;
            if (idx == 0 || userLocks[msg.sender][idx - 1].unlockTime < unlockTime) {
                userLocks[msg.sender].push(LockedBalance({amount: amount, unlockTime: unlockTime}));
            } else {
                userLocks[msg.sender][idx - 1].amount = userLocks[msg.sender][idx - 1].amount.add(amount);
            }
        } else {
            bal.unlocked = bal.unlocked.add(amount);
        }
        stakingToken.safeTransferFrom(msg.sender, address(this), amount);
        emit Staked(msg.sender, amount);
    }

    // Mint new tokens
    // Minted tokens receive rewards normally but incur a 50% penalty when
    // withdrawn before lockDuration has passed.
    function mint(address user, uint256 amount) external updateReward(user) {
        require(minters[msg.sender], "MultiFeeDistribution::mint: Only minters allowed");

        totalSupply = totalSupply.add(amount);
        Balances storage bal = balances[user];
        bal.total = bal.total.add(amount);
        bal.earned = bal.earned.add(amount);
        uint256 unlockTime = block.timestamp.div(groupDuration).mul(groupDuration).add(lockDuration);
        LockedBalance[] storage earnings = userEarnings[user];
        uint256 idx = earnings.length;

        if (idx == 0 || earnings[idx - 1].unlockTime < unlockTime) {
            earnings.push(LockedBalance({amount: amount, unlockTime: unlockTime}));
        } else {
            earnings[idx - 1].amount = earnings[idx - 1].amount.add(amount);
        }
        emit Staked(user, amount);
    }

    // Withdraw staked tokens
    // First withdraws unlocked tokens, then earned tokens. Withdrawing earned tokens
    // incurs a 50% penalty which is distributed based on locked balances.
    function withdraw(uint256 amount) public nonReentrant updateReward(msg.sender) {
        require(amount > 0, "MultiFeeDistribution::withdraw: Cannot withdraw 0");
        Balances storage bal = balances[msg.sender];
        uint256 penaltyAmount;

        if (amount <= bal.unlocked) {
            bal.unlocked = bal.unlocked.sub(amount);
        } else {
            uint256 remaining = amount.sub(bal.unlocked);
            require(bal.earned >= remaining, "MultiFeeDistribution::withdraw: Insufficient unlocked balance");
            bal.unlocked = 0;
            bal.earned = bal.earned.sub(remaining);
            for (uint256 i = 0; ; i++) {
                uint256 earnedAmount = userEarnings[msg.sender][i].amount;
                if (earnedAmount == 0) continue;
                if (penaltyAmount == 0 && userEarnings[msg.sender][i].unlockTime > block.timestamp) {
                    penaltyAmount = remaining;
                    require(bal.earned >= remaining, "MultiFeeDistribution::withdraw: Insufficient balance after penalty");
                    bal.earned = bal.earned.sub(remaining);
                    if (bal.earned == 0) {
                        delete userEarnings[msg.sender];
                        break;
                    }
                    if (bal.earned == 1) {
                        delete userEarnings[msg.sender];
                        penaltyAmount = penaltyAmount.add(1);
                        break;
                    }
                    remaining = remaining.mul(2);
                }
                if (remaining <= earnedAmount) {
                    userEarnings[msg.sender][i].amount = earnedAmount.sub(remaining);
                    break;
                } else {
                    delete userEarnings[msg.sender][i];
                    remaining = remaining.sub(earnedAmount);
                }
            }
        }

        uint256 adjustedAmount = amount.add(penaltyAmount);
        bal.total = bal.total.sub(adjustedAmount);
        totalSupply = totalSupply.sub(adjustedAmount);
        stakingToken.safeTransfer(msg.sender, amount);
        if (penaltyAmount > 0) {
            _notifyReward(address(stakingToken), penaltyAmount);
        }
        emit Withdrawn(msg.sender, amount);
    }

    // Claim all pending staking rewards
    function getReward() public nonReentrant updateReward(msg.sender) {
        for (uint256 i; i < rewardTokens.length; i++) {
            address _rewardToken = rewardTokens[i];
            uint256 reward = rewards[msg.sender][_rewardToken];
            if (reward > 0) {
                rewards[msg.sender][_rewardToken] = 0;
                IERC20(_rewardToken).safeTransfer(msg.sender, reward);
                emit RewardPaid(msg.sender, _rewardToken, reward);
            }
        }
    }

    // Withdraw full unlocked balance and claim pending rewards
    function emergencyWithdraw() external updateReward(msg.sender) {
        (uint256 amount, uint256 penaltyAmount) = withdrawableBalance(msg.sender);
        delete userEarnings[msg.sender];
        Balances storage bal = balances[msg.sender];
        bal.total = bal.total.sub(bal.unlocked).sub(bal.earned);
        bal.unlocked = 0;
        bal.earned = 0;

        totalSupply = totalSupply.sub(amount.add(penaltyAmount));
        stakingToken.safeTransfer(msg.sender, amount);
        if (penaltyAmount > 0) {
            _notifyReward(address(stakingToken), penaltyAmount);
        }
        getReward();
    }

    // Withdraw all currently locked tokens where the unlock time has passed
    function withdrawExpiredLocks() external {
        LockedBalance[] storage locks = userLocks[msg.sender];
        Balances storage bal = balances[msg.sender];
        uint256 amount;
        uint256 length = locks.length;
        if (locks[length - 1].unlockTime <= block.timestamp) {
            amount = bal.locked;
            delete userLocks[msg.sender];
        } else {
            for (uint256 i = 0; i < length; i++) {
                if (locks[i].unlockTime > block.timestamp) break;
                amount = amount.add(locks[i].amount);
                delete locks[i];
            }
        }
        bal.locked = bal.locked.sub(amount);
        bal.total = bal.total.sub(amount);
        totalSupply = totalSupply.sub(amount);
        lockedSupply = lockedSupply.sub(amount);
        stakingToken.safeTransfer(msg.sender, amount);
    }

    /* ========== RESTRICTED FUNCTIONS ========== */

    function _notifyReward(address _rewardsToken, uint256 reward) internal {
        if (block.timestamp >= rewardData[_rewardsToken].periodFinish) {
            rewardData[_rewardsToken].rewardRate = reward.div(rewardsDuration);
        } else {
            uint256 remaining = rewardData[_rewardsToken].periodFinish.sub(block.timestamp);
            uint256 leftover = remaining.mul(rewardData[_rewardsToken].rewardRate);
            rewardData[_rewardsToken].rewardRate = reward.add(leftover).div(rewardsDuration);
        }

        rewardData[_rewardsToken].lastUpdateTime = block.timestamp;
        rewardData[_rewardsToken].periodFinish = block.timestamp.add(rewardsDuration);
    }

    function notifyRewardAmount(address _rewardsToken, uint256 reward) external updateReward(address(0)) {
        require(rewardDistributors[_rewardsToken][msg.sender], "MultiFeeDistribution::notifyRewardAmount: Only reward distributors allowed");
        require(reward > 0, "MultiFeeDistribution::notifyRewardAmount: No reward");
        // handle the transfer of reward tokens via `transferFrom` to reduce the number
        // of transactions required and ensure correctness of the reward amount
        IERC20(_rewardsToken).safeTransferFrom(msg.sender, address(this), reward);
        _notifyReward(_rewardsToken, reward);
        emit RewardAdded(reward);
    }

    // Added to support recovering LP Rewards from other systems such as BAL to be distributed to holders
    function recoverERC20(address tokenAddress, uint256 tokenAmount) external onlyOwner {
        require(tokenAddress != address(stakingToken), "MultiFeeDistribution::recoverERC20: Cannot withdraw staking token");
        require(rewardData[tokenAddress].lastUpdateTime == 0, "MultiFeeDistribution::recoverERC20: Cannot withdraw reward token");
        IERC20(tokenAddress).safeTransfer(owner(), tokenAmount);
        emit Recovered(tokenAddress, tokenAmount);
    }

    /* ========== MODIFIERS ========== */

    modifier updateReward(address account) {
        address token = address(stakingToken);
        uint256 balance;
        uint256 supply = lockedSupply;
        rewardData[token].rewardPerTokenStored = _rewardPerToken(token, supply);
        rewardData[token].lastUpdateTime = lastTimeRewardApplicable(token);
        if (account != address(0)) {
            // Special case, use the locked balances and supply for stakingReward rewards
            rewards[account][token] = _earned(account, token, balances[account].locked, supply);
            userRewardPerTokenPaid[account][token] = rewardData[token].rewardPerTokenStored;
            balance = balances[account].total;
        }

        supply = totalSupply;
        for (uint256 i = 1; i < rewardTokens.length; i++) {
            token = rewardTokens[i];
            rewardData[token].rewardPerTokenStored = _rewardPerToken(token, supply);
            rewardData[token].lastUpdateTime = lastTimeRewardApplicable(token);
            if (account != address(0)) {
                rewards[account][token] = _earned(account, token, balance, supply);
                userRewardPerTokenPaid[account][token] = rewardData[token].rewardPerTokenStored;
            }
        }
        _;
    }

    /* ========== EVENTS ========== */

    event RewardAdded(uint256 reward);
    event RewardTokenAdded(address indexed rewardTokenAddress);
    event RewardDistributorApproved(address indexed rewardAddress, address indexed distributor, bool approved);
    event Staked(address indexed user, uint256 amount);
    event Withdrawn(address indexed user, uint256 amount);
    event RewardPaid(address indexed user, address indexed rewardsToken, uint256 reward);
    event Recovered(address token, uint256 amount);

    function _become(StrikeStakingProxy stakingProxy) public {
        require(msg.sender == stakingProxy.admin(), "only staking proxy admin can change brains");
        stakingProxy._acceptImplementation();
    }

    /**
      * @notice Accepts transfer of admin rights. msg.sender must be pendingAdmin
      * @dev Admin function for pending admin to accept role and update admin
      * @return uint 0=success, otherwise a failure
      */
    function _acceptAdminInImplementation() public {
        require(msg.sender == pendingAdmin && msg.sender != address(0), "ACCEPT_ADMIN_PENDING_ADMIN_CHECK");

        // Save current values for inclusion in log
        address oldAdmin = admin;
        address oldPendingAdmin = pendingAdmin;

        // Store admin with value pendingAdmin
        admin = pendingAdmin;

        // Clear the pending value
        pendingAdmin = address(0);

        emit NewAdmin(oldAdmin, admin);
        emit NewPendingAdmin(oldPendingAdmin, pendingAdmin);
    }
}