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



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (access/Ownable.sol)

pragma solidity ^0.8.0;

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

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

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

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_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 {
        _transferOwnership(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");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

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



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

pragma solidity ^0.8.0;

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

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

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

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

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

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

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

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

// File: @openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol



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

pragma solidity ^0.8.0;

import "../IERC20.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 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'
        require(
            (value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

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

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

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

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

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



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

pragma solidity ^0.8.1;

/**
 * @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
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 0;
    }

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

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

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

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

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

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

        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResult(success, returndata, errorMessage);
    }

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

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

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

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

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

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

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

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

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



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

pragma solidity ^0.8.0;

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

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

// File: contracts/interfaces/IVotingEscrow.sol



pragma solidity 0.8.12;

interface IVotingEscrow {
    struct Point {
        int128 bias;
        int128 slope; // # -dweight / dt
        uint256 ts;
        uint256 blk; // block
    }

    function locked__end(uint _tokenId) external view returns (uint);

    function ownerOf(uint _tokenId) external view returns (address);

    function user_point_epoch(uint tokenId) external view returns (uint);

    function user_point_history(
        uint tokenId,
        uint loc
    ) external view returns (Point memory);

    function deposit_for(uint tokenId, uint value) external;

    function token() external view returns (address);

    function supply() external view returns (uint256);
}
// File: contracts/VeDistStableAPY.sol



pragma solidity 0.8.12;

import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "./interfaces/IVotingEscrow.sol";

contract VeDistStableAPY is Ownable {
    using SafeERC20 for IERC20;

    struct Reward {
        uint256 timestamp;
        uint256 amount;
        uint256 supply;
    }

    mapping(uint256 => Reward) public rewards;
    mapping(uint256 => uint256) public nextUserRewards; // TokenId => LastReward
    mapping(uint256 => uint256) public userTokenEpoch;
    uint256 public lastReward;

    address public immutable ve;
    address public immutable token;

    address rewardProvider;
    uint256 minRewardAmount;

    uint256 internal constant MAXTIME = 4 * 365 * 86400;

    event RewardDistributed(
        uint256 indexed index,
        uint256 indexed timestamp,
        uint256 amount,
        uint256 supply
    );
    event RewardClaimed(
        uint256 indexed tokenId,
        uint256 indexed index,
        uint256 amount
    );
    event RewardProviderSet(address rewardProvider);
    event MinRewardAmountSet(uint256 minRewardAmount);

    constructor(address _ve, address _rewardProvider, uint256 _minRewardAmount) {
        ve = _ve;
        _setRewardProvider(_rewardProvider);
        _setMinRewardAmount(_minRewardAmount);
        token = IVotingEscrow(ve).token();
        IERC20(token).approve(ve, type(uint256).max);
    }

    function setRewardProvider(address _rewardProvider) external onlyOwner {
        _setRewardProvider(_rewardProvider);
    }

    function setMinRewardAmount(uint256 _minRewardAmount) external onlyOwner {
        _setMinRewardAmount(_minRewardAmount);
    }

    /// @dev Transfer token to this contract as rewards
    function addReward(uint256 amount) external {
        require(amount > 0, "No tokens transfered");
        require(amount >= minRewardAmount, "Reward amount is too low");
        address provider = rewardProvider;
        require(provider == address(0) || provider == msg.sender, "You are not reward provider");
        IERC20(token).safeTransferFrom(msg.sender, address(this), amount);
        uint256 index = lastReward++;
        uint256 supply = _getTotalLocked();
        Reward storage curReward = rewards[index];
        curReward.timestamp = block.timestamp;
        curReward.amount = amount;
        curReward.supply = supply;
        require(supply > 0, "No tokens locked. Reward is useless");
        emit RewardDistributed(index, block.timestamp, amount, supply);
    }

    /// @dev claim all allowed rewards for this tokenId
    function claim(uint256 tokenId) public returns (uint256 reward) {
        address tokenOwner = IVotingEscrow(ve).ownerOf(tokenId);
        require(msg.sender == tokenOwner, "Only owner can claim rewards");
        uint256 nextUserReward = nextUserRewards[tokenId];

        if (nextUserReward == 0) {
            nextUserReward = _skipRoundsBeforeCreation(tokenId);
        }

        uint256 tokenLocked;
        uint256 curUserTokenEpoch = userTokenEpoch[tokenId];
        bool expired;

        for (int i = 0; i < 50; i++) {
            if (nextUserReward >= lastReward) {
                break; // No paiments was done in this point
            }

            Reward memory curReward = rewards[nextUserReward];
            (tokenLocked, curUserTokenEpoch, expired) = _getTokenLocked(
                tokenId,
                curReward.timestamp,
                curUserTokenEpoch
            );

            if (expired) {
                break;
            }
            uint256 curRoundReward = (curReward.amount * tokenLocked) /
                curReward.supply;
            emit RewardClaimed(tokenId, nextUserReward, curRoundReward);

            reward += curRoundReward;
            nextUserReward++;
        }

        userTokenEpoch[tokenId] = curUserTokenEpoch;
        nextUserRewards[tokenId] = nextUserReward;

        if (reward > 0) {
            if (IVotingEscrow(ve).locked__end(tokenId) < block.timestamp) {
                IERC20(token).safeTransfer(tokenOwner, reward);
            } else {
                IVotingEscrow(ve).deposit_for(tokenId, reward);
            }
        }
    }

    function claimMany(
        uint256[] calldata tokensId
    ) external returns (uint256 totalRewards) {
        for (uint256 i = 0; i < tokensId.length; i++) {
            totalRewards += claim(tokensId[i]);
        }
    }

    /// @dev View version of claim function
    function claimable(uint256 tokenId) external view returns (uint256 reward) {
        uint256 nextUserReward = nextUserRewards[tokenId];

        if (nextUserReward == 0) {
            nextUserReward = _skipRoundsBeforeCreation(tokenId);
        }

        uint256 tokenLocked;
        uint256 curUserTokenEpoch = userTokenEpoch[tokenId];
        bool expired;

        for (int i = 0; i < 50; i++) {
            if (nextUserReward >= lastReward) {
                break; // No paiments was done in this point
            }

            Reward memory curReward = rewards[nextUserReward];
            (tokenLocked, curUserTokenEpoch, expired) = _getTokenLocked(
                tokenId,
                curReward.timestamp,
                curUserTokenEpoch
            );

            if (expired) {
                break;
            }

            reward += (curReward.amount * tokenLocked) / curReward.supply;
            nextUserReward++;
        }
    }

    /// @dev Get total amount of CHO locked in ve contract
    function _getTotalLocked() internal view returns (uint256) {
        return IVotingEscrow(ve).supply();
    }

    /// @dev Calculate how many token were locked in lock at the given time
    function _getTokenLocked(
        uint256 tokenId,
        uint256 timestamp,
        uint256 curUserTokenEpoch
    ) internal view returns (uint256, uint256, bool) {
        uint256 maxUserEpoch = IVotingEscrow(ve).user_point_epoch(tokenId);
        uint256 tokenLocked;
        bool finished;
        uint256 duration;

        if (maxUserEpoch == 0) {
            return (0, curUserTokenEpoch, true);
        }

        if (curUserTokenEpoch == 0) {
            curUserTokenEpoch = 1;
        }

        IVotingEscrow.Point memory prevPoint = IVotingEscrow(ve)
            .user_point_history(tokenId, curUserTokenEpoch);

        if (prevPoint.ts > timestamp) {
            return (0, curUserTokenEpoch, false);
        }

        while (curUserTokenEpoch < maxUserEpoch) {
            curUserTokenEpoch++;
            IVotingEscrow.Point memory nextPoint = IVotingEscrow(ve)
                .user_point_history(tokenId, curUserTokenEpoch);

            if (nextPoint.ts > timestamp) {
                curUserTokenEpoch--;
                (tokenLocked, duration) = _calcTokenLocked(
                    uint256(int256(prevPoint.bias)),
                    uint256(int256(prevPoint.slope))
                );
                break;
            } else {
                prevPoint = nextPoint;
            }
        }

        if (curUserTokenEpoch == maxUserEpoch) {
            (tokenLocked, duration) = _calcTokenLocked(
                uint256(int256(prevPoint.bias)),
                uint256(int256(prevPoint.slope))
            );
        }

        finished = prevPoint.ts + duration < timestamp;

        if (finished) {
            tokenLocked = 0;
        }

        return (tokenLocked, curUserTokenEpoch, finished);
    }

    /// @dev Calculate how many tokens was locked based on bias and slope
    ///			Ve contract dont store that information, but we know, that
    ///			if duration of lock was MAXTIME, than 1 locked CHO = 1 veCHO.
    ///			Knowing that and fact, that amount of veCHO decreasing due to
    ///			linear law, we can calculate locked amount using similarity of triangles
    function _calcTokenLocked(
        uint256 bias,
        uint256 slope
    ) internal pure returns (uint256 baseValue, uint256 duration) {
        duration = bias / slope;
        baseValue = (MAXTIME * bias) / duration;
    }

    function _setRewardProvider(address _rewardProvider) internal {
        rewardProvider = _rewardProvider;
        emit RewardProviderSet(_rewardProvider);
    }

    function _setMinRewardAmount(uint256 _minRewardAmount) internal {
        minRewardAmount = _minRewardAmount;
        emit MinRewardAmountSet(_minRewardAmount);
    }

    /// @dev Count what is first reward, that was given after lock creation
    function _skipRoundsBeforeCreation(
        uint256 tokenId
    ) internal view returns (uint256 newRound) {
        IVotingEscrow.Point memory firstPoint = IVotingEscrow(ve)
            .user_point_history(tokenId, 1);

        uint256 left = 0;
        uint256 right = lastReward;
        uint256 mid = (right + left) / 2;

        while (right - left > 1) {
            uint256 curTimestamp = rewards[mid].timestamp;
            if (firstPoint.ts > curTimestamp) {
                left = mid;
                mid = (right + left) / 2;
            } else {
                right = mid;
                mid = (right + left) / 2;
            }
        }

        return left;
    }
}