// File: contracts/wrapper/WrappingRewards.sol



// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.7.6;

import "@openzeppelin/contracts/math/SafeMath.sol";
import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";
import "../interfaces/ISovWrapper.sol";
import "../interfaces/IBasketBalancer.sol";
import "../interfaces/IReign.sol";
import "../libraries/LibRewardsDistribution.sol";

contract WrappingRewards {
    // lib
    using SafeMath for uint256;
    using SafeMath for uint128;
    using SafeERC20 for IERC20;

    // state variables

    uint256 public constant NO_VOTE_PENALTY = 3 * 10**16; // -3%
    uint256 private constant BASE_MULTIPLIER = 10**18;

    // addresses
    address public treasury;
    address public rewardsVault;
    address public basketBalancer;

    // contracts
    IERC20 public reignToken;
    ISovWrapper public wrapper;

    uint128 public lastInitializedEpoch;
    uint256 public epochDuration; // init from staking contract
    uint256 public epochStart; // init from staking contract

    mapping(uint128 => uint256) private _sizeAtEpoch;
    mapping(address => uint128) private _lastEpochIdHarvested;

    // events
    event MassHarvest(
        address indexed user,
        uint256 epochsHarvested,
        uint256 totalValue
    );
    event Harvest(
        address indexed user,
        uint128 indexed epochId,
        uint256 amount
    );

    event InitEpoch(address indexed caller, uint128 indexed epochId);

    // constructor
    constructor(
        address _reignTokenAddress,
        address _basketBalancer,
        address _wrappingContract,
        address _rewardsVault,
        address _treasury
    ) {
        reignToken = IERC20(_reignTokenAddress);
        wrapper = ISovWrapper(_wrappingContract);
        rewardsVault = _rewardsVault;
        basketBalancer = _basketBalancer;
        epochDuration = wrapper.epochDuration();
        epochStart = wrapper.epoch1Start() + epochDuration;
        treasury = _treasury;
    }

    // public method to harvest all the unharvested epochs until current epoch - 1
    function massHarvest() external returns (uint256) {
        uint256 totalDistributedValue;
        uint256 epochId = _getEpochId().sub(1); // fails in epoch 0

        for (
            uint128 i = _lastEpochIdHarvested[msg.sender] + 1;
            i <= epochId;
            i++
        ) {
            // i = epochId
            // compute distributed Value and do one single transfer at the end
            totalDistributedValue += _harvest(i);
        }

        if (totalDistributedValue > 0) {
            reignToken.safeTransferFrom(
                rewardsVault,
                msg.sender,
                totalDistributedValue
            );
        }

        emit MassHarvest(
            msg.sender,
            epochId - _lastEpochIdHarvested[msg.sender],
            totalDistributedValue
        );

        return totalDistributedValue;
    }

    //gets the rewards for a single epoch
    function harvest(uint128 epochId) external returns (uint256) {
        // checks for requested epoch
        require(_getEpochId() > epochId, "This epoch is in the future");
        require(
            _lastEpochIdHarvested[msg.sender].add(1) == epochId,
            "Can only harvest in order"
        );

        uint256 userReward = _harvest(epochId);
        if (userReward > 0) {
            reignToken.safeTransferFrom(rewardsVault, msg.sender, userReward);
        }

        emit Harvest(msg.sender, epochId, userReward);
        return userReward;
    }

    // transfer the entire fees collected in this contract to DAO treasury
    function collectFeesToDAO() public {
        uint256 balance = IERC20(reignToken).balanceOf(address(this));
        IERC20(reignToken).safeTransfer(treasury, balance);
    }

    /*
     *   VIEWS
     */

    //returns the current epoch
    function getCurrentEpoch() external view returns (uint256) {
        return _getEpochId();
    }

    // gets the total amount of rewards accrued to a pool during an epoch
    function getRewardsForEpoch() public view returns (uint256) {
        uint256 epochRewards = LibRewardsDistribution
            .wrappingRewardsPerEpochTotal(epochStart); //this accounts for2 year halving already
        return epochRewards;
    }

    // calls to the staking smart contract to retrieve user balance for an epoch
    function getEpochStake(address userAddress, uint128 epochId)
        external
        view
        returns (uint256)
    {
        return _getUserBalancePerEpoch(userAddress, epochId);
    }

    function userLastEpochIdHarvested() external view returns (uint256) {
        return _lastEpochIdHarvested[msg.sender];
    }

    // calls to the staking smart contract to retrieve the epoch total poolLP size
    function getPoolSize(uint128 epochId) external view returns (uint256) {
        return _getPoolSize(epochId);
    }

    // checks if the user has voted that epoch and returns accordingly
    function isBoosted(address user, uint128 epoch) public view returns (bool) {
        IBasketBalancer basketBalancer = IBasketBalancer(basketBalancer);
        address _reign = basketBalancer.reignDiamond();
        // if user or users delegate has voted
        if (
            basketBalancer.hasVotedInEpoch(
                user,
                epoch + 1 // basketBalancer epoch is 1 higher then this
            ) ||
            basketBalancer.hasVotedInEpoch(
                IReign(_reign).userDelegatedTo(user),
                epoch + 1 // basketBalancer epoch is 1 higher then this
            )
        ) {
            return true;
        } else {
            return false; // apply -3%
        }
    }

    function getUserRewardsForEpoch(uint128 epochId)
        public
        view
        returns (uint256)
    {
        // exit if there is no stake on the epoch
        if (_sizeAtEpoch[epochId] == 0) {
            return 0;
        }

        uint256 epochRewards = getRewardsForEpoch();
        bool boost = isBoosted(msg.sender, epochId);

        // get users share of rewards
        uint256 userEpochRewards = epochRewards
            .mul(_getUserBalancePerEpoch(msg.sender, epochId))
            .div(_sizeAtEpoch[epochId]);

        //if user is not boosted pull penalty into this contract and reduce user rewards
        if (!boost) {
            uint256 penalty = userEpochRewards.mul(NO_VOTE_PENALTY).div(
                BASE_MULTIPLIER
            ); // decrease by 3%

            userEpochRewards = userEpochRewards.sub(penalty);
        }

        return userEpochRewards;
    }

    /**
        INTERNAL
     */

    function _harvest(uint128 epochId) internal returns (uint256) {
        // try to initialize an epoch
        if (lastInitializedEpoch < epochId) {
            _initEpoch(epochId);
        }
        // Set user state for last harvested
        _lastEpochIdHarvested[msg.sender] = epochId;

        // exit if there is no stake on the epoch
        if (_sizeAtEpoch[epochId] == 0) {
            return 0;
        }

        uint256 epochRewards = getRewardsForEpoch();
        bool boost = isBoosted(msg.sender, epochId);

        // get users share of rewards
        uint256 userEpochRewards = epochRewards
            .mul(_getUserBalancePerEpoch(msg.sender, epochId))
            .div(_sizeAtEpoch[epochId]);

        //if user is not boosted pull penalty into this contract and reduce user rewards
        if (!boost) {
            uint256 penalty = userEpochRewards.mul(NO_VOTE_PENALTY).div(
                BASE_MULTIPLIER
            ); // decrease by 3%

            userEpochRewards = userEpochRewards.sub(penalty);

            reignToken.safeTransferFrom(rewardsVault, address(this), penalty);
        }

        return userEpochRewards;
    }

    function _initEpoch(uint128 epochId) internal {
        //epochs can only be harvested in order, therfore they can also only be initialised in order
        // i.e it's impossible that we init epoch 5 after 3 as to harvest 5 user needs to first harvets 4
        _sizeAtEpoch[epochId] = _getPoolSize(epochId);
        lastInitializedEpoch = epochId;
        // call the staking smart contract to init the epoch

        emit InitEpoch(msg.sender, epochId);
    }

    function _getPoolSize(uint128 epochId) internal view returns (uint256) {
        // retrieve unilp token balance
        return wrapper.getEpochPoolSize(_wrapperEpochId(epochId));
    }

    function _getUserBalancePerEpoch(address userAddress, uint128 epochId)
        internal
        view
        returns (uint256)
    {
        // retrieve unilp token balance per user per epoch
        return
            wrapper.getEpochUserBalance(userAddress, _wrapperEpochId(epochId));
    }

    // compute epoch id from blocktimestamp and
    function _getEpochId() internal view returns (uint128 epochId) {
        if (block.timestamp < epochStart) {
            return 0;
        }
        epochId = uint128(
            block.timestamp.sub(epochStart).div(epochDuration).add(1)
        );
    }

    // get the staking epoch which is 1 epoch more
    function _wrapperEpochId(uint128 epochId) internal pure returns (uint128) {
        return epochId + 1;
    }
}

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



// SPDX-License-Identifier: MIT

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/SafeERC20.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "./IERC20.sol";
import "../../math/SafeMath.sol";
import "../../utils/Address.sol";

/**
 * @title SafeERC20
 * @dev Wrappers around ERC20 operations that throw on failure (when the token
 * contract returns false). Tokens that return no value (and instead revert or
 * throw on failure) are also supported, non-reverting calls are assumed to be
 * successful.
 * To use this library you can add a `using SafeERC20 for IERC20;` statement to your contract,
 * which allows you to call the safe operations as `token.safeTransfer(...)`, etc.
 */
library SafeERC20 {
    using 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));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(IERC20 token, address spender, uint256 value) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        // 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. We use {Address.functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

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

// File: contracts/interfaces/ISovWrapper.sol



// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.7.6;

interface ISovWrapper {
    function deposit(
        address user,
        uint256 amount,
        uint256 liquidationPrice
    ) external;

    function withdraw(address lpOwner, uint256 amount) external;

    function liquidate(
        address liquidator,
        address from,
        uint256 amount
    ) external;

    function liquidationFee(address) external view returns (uint256);

    function epochDuration() external view returns (uint256);

    function epoch1Start() external view returns (uint256);

    function getEpochUserBalance(address user, uint128 epoch)
        external
        view
        returns (uint256);

    function getEpochPoolSize(uint128 epoch) external view returns (uint256);
}

// File: contracts/interfaces/IBasketBalancer.sol



// SPDX-License-Identifier: Apache-2.0
pragma solidity 0.7.6;

interface IBasketBalancer {
    function addToken(address, uint256) external returns (uint256);

    function hasVotedInEpoch(address, uint128) external view returns (bool);

    function getTargetAllocation(address) external view returns (uint256);

    function full_allocation() external view returns (uint256);

    function updateBasketBalance() external;

    function reignDiamond() external view returns (address);

    function getTokens() external view returns (address[] memory);
}

// File: contracts/interfaces/IReign.sol



// SPDX-License-Identifier: Apache-2.0
pragma solidity 0.7.6;
pragma experimental ABIEncoderV2;

import "../libraries/LibReignStorage.sol";

interface IReign {
    function BASE_MULTIPLIER() external view returns (uint256);

    // deposit allows a user to add more bond to his staked balance
    function deposit(uint256 amount) external;

    // withdraw allows a user to withdraw funds if the balance is not locked
    function withdraw(uint256 amount) external;

    // lock a user's currently staked balance until timestamp & add the bonus to his voting power
    function lock(uint256 timestamp) external;

    // delegate allows a user to delegate his voting power to another user
    function delegate(address to) external;

    // stopDelegate allows a user to take back the delegated voting power
    function stopDelegate() external;

    // lock the balance of a proposal creator until the voting ends; only callable by DAO
    function lockCreatorBalance(address user, uint256 timestamp) external;

    // balanceOf returns the current BOND balance of a user (bonus not included)
    function balanceOf(address user) external view returns (uint256);

    // balanceAtTs returns the amount of BOND that the user currently staked (bonus NOT included)
    function balanceAtTs(address user, uint256 timestamp)
        external
        view
        returns (uint256);

    // stakeAtTs returns the Stake object of the user that was valid at `timestamp`
    function stakeAtTs(address user, uint256 timestamp)
        external
        view
        returns (LibReignStorage.Stake memory);

    // votingPower returns the voting power (bonus included) + delegated voting power for a user at the current block
    function votingPower(address user) external view returns (uint256);

    // votingPowerAtTs returns the voting power (bonus included) + delegated voting power for a user at a point in time
    function votingPowerAtTs(address user, uint256 timestamp)
        external
        view
        returns (uint256);

    // bondStaked returns the total raw amount of BOND staked at the current block
    function reignStaked() external view returns (uint256);

    // reignStakedAtTs returns the total raw amount of BOND users have deposited into the contract
    // it does not include any bonus
    function reignStakedAtTs(uint256 timestamp) external view returns (uint256);

    // delegatedPower returns the total voting power that a user received from other users
    function delegatedPower(address user) external view returns (uint256);

    // delegatedPowerAtTs returns the total voting power that a user received from other users at a point in time
    function delegatedPowerAtTs(address user, uint256 timestamp)
        external
        view
        returns (uint256);

    // stakingBoost calculates the multiplier on the user's stake at the current timestamp
    function stakingBoost(address user) external view returns (uint256);

    // stackingBoostAtTs calculates the multiplier at a given timestamp based on the user's stake a the given timestamp
    function stackingBoostAtTs(address user, uint256 timestamp)
        external
        view
        returns (uint256);

    // userLockedUntil returns the timestamp until the user's balance is locked
    function userLockedUntil(address user) external view returns (uint256);

    // userDidDelegate returns the address to which a user delegated their voting power; address(0) if not delegated
    function userDelegatedTo(address user) external view returns (address);

    // returns the last timestamp in which the user intercated with the staking contarct
    function userLastAction(address user) external view returns (uint256);

    // reignCirculatingSupply returns the current circulating supply of BOND
    function reignCirculatingSupply() external view returns (uint256);

    function getEpochDuration() external view returns (uint256);

    function getEpoch1Start() external view returns (uint256);

    function getCurrentEpoch() external view returns (uint128);

    function stakingBoostAtEpoch(address, uint128)
        external
        view
        returns (uint256);

    function getEpochUserBalance(address, uint128)
        external
        view
        returns (uint256);
}

// File: contracts/libraries/LibRewardsDistribution.sol



// SPDX-License-Identifier: Apache-2.0
pragma solidity 0.7.6;
pragma experimental ABIEncoderV2;
import "@openzeppelin/contracts/math/SafeMath.sol";

library LibRewardsDistribution {
    using SafeMath for uint256;

    uint256 public constant TOTAL_REIGN_SUPPLY = 1_000_000_000 * 10**18;

    uint256 public constant WRAPPING_TOKENS = 500_000_000 * 10**18;
    uint256 public constant TEAM = 140_000_000 * 10**18;
    uint256 public constant TREASURY_SALE = 120_000_000 * 10**18;
    uint256 public constant STAKING_TOKENS = 100_000_000 * 10**18;
    uint256 public constant TREASURY = 50_000_000 * 10**18;
    uint256 public constant DEV_FUND = 50_000_000 * 10**18;
    uint256 public constant LP_REWARDS_TOKENS = 40_000_000 * 10**18;

    uint256 public constant HALVING_PERIOD = 62899200; // 104 Weeks in Seconds
    uint256 public constant EPOCHS_IN_PERIOD = 104; // Weeks in 2 years
    uint256 public constant BLOCKS_IN_PERIOD = 2300000 * 2;
    uint256 public constant BLOCKS_IN_EPOCH = 44230;

    uint256 public constant TOTAL_ALLOCATION = 1000000000;

    /*
     *   WRAPPING
     */

    function wrappingRewardsPerEpochTotal(uint256 epoch1start)
        internal
        view
        returns (uint256)
    {
        return wrappingRewardsPerPeriodTotal(epoch1start) / EPOCHS_IN_PERIOD;
    }

    function wrappingRewardsPerPeriodTotal(uint256 epoch1start)
        internal
        view
        returns (uint256)
    {
        uint256 _timeElapsed = (block.timestamp.sub(epoch1start));
        uint256 _periodNr = (_timeElapsed / HALVING_PERIOD).add(1); // this creates the 2 year step function
        return WRAPPING_TOKENS.div(2 * _periodNr);
    }

    /*
     *   GOV STAKING
     */

    function rewardsPerEpochStaking(uint256 epoch1start)
        internal
        view
        returns (uint256)
    {
        return stakingRewardsPerPeriodTotal(epoch1start) / EPOCHS_IN_PERIOD;
    }

    function stakingRewardsPerPeriodTotal(uint256 epoch1start)
        internal
        view
        returns (uint256)
    {
        if (epoch1start > block.timestamp) {
            return 0;
        }
        uint256 _timeElapsed = (block.timestamp.sub(epoch1start));
        uint256 _periodNr = (_timeElapsed / HALVING_PERIOD).add(1); // this creates the 2 year step function
        return STAKING_TOKENS.div(2 * _periodNr);
    }

    /*
     *   LP REWARDS
     */

    function rewardsPerEpochLPRewards(uint256 totalAmount, uint256 nrOfEpochs)
        internal
        view
        returns (uint256)
    {
        return totalAmount / nrOfEpochs;
    }
}

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



// SPDX-License-Identifier: MIT

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: @openzeppelin/contracts/utils/Address.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.2 <0.8.0;

/**
 * @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) {
        // This method relies on extcodesize, which returns 0 for contracts in
        // construction, since the code is only stored at the end of the
        // constructor execution.

        uint256 size;
        // solhint-disable-next-line no-inline-assembly
        assembly { size := extcodesize(account) }
        return size > 0;
    }

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

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (bool success, ) = recipient.call{ value: amount }("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

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

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        require(isContract(target), "Address: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.call{ value: value }(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data, string memory errorMessage) internal view returns (bytes memory) {
        require(isContract(target), "Address: static call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.staticcall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        require(isContract(target), "Address: delegate call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.delegatecall(data);
        return _verifyCallResult(success, returndata, errorMessage);
    }

    function _verifyCallResult(bool success, bytes memory returndata, string memory errorMessage) private pure returns(bytes memory) {
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

// File: contracts/libraries/LibReignStorage.sol



// SPDX-License-Identifier: Apache-2.0
pragma solidity 0.7.6;
pragma experimental ABIEncoderV2;

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

library LibReignStorage {

    bytes32 constant STORAGE_POSITION = keccak256("org.sovreign.reign.storage");

    struct Checkpoint {
        uint256 timestamp;
        uint256 amount;
    }

    struct EpochBalance {
        uint128 epochId;
        uint128 multiplier;
        uint256 startBalance;
        uint256 newDeposits;
    }

    struct Stake {
        uint256 timestamp;
        uint256 amount;
        uint256 expiryTimestamp;
        address delegatedTo;
        uint256 stakingBoost;
    }

    struct Storage {
        bool initialized;
        // mapping of user address to history of Stake objects
        // every user action creates a new object in the history
        mapping(address => Stake[]) userStakeHistory;
        mapping(address => EpochBalance[]) userBalanceHistory;
        mapping(address => uint128) lastWithdrawEpochId;
        // array of reign staked Checkpoint
        // deposits/withdrawals create a new object in the history (max one per block)
        Checkpoint[] reignStakedHistory;
        // mapping of user address to history of delegated power
        // every delegate/stopDelegate call create a new checkpoint (max one per block)
        mapping(address => Checkpoint[]) delegatedPowerHistory;
        IERC20 reign; // the reign Token
        uint256 epoch1Start;
        uint256 epochDuration;
    }

    function reignStorage() internal pure returns (Storage storage ds) {
        bytes32 position = STORAGE_POSITION;
        assembly {
            ds.slot := position
        }
    }
}