// File: /contracts/KitsuMintuRaffleContract.sol



// SPDX-License-Identifier: MIT

import "./libs/SafeMath.sol";
import "./libs/SignedSafeMath.sol";

/**
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⣀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣀⡀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣾⠙⠻⢶⣄⡀⠀⠀⠀⢀⣤⠶⠛⠛⡇⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢹⣇⠀⠀⣙⣿⣦⣤⣴⣿⣁⠀⠀⣸⠇⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠙⣡⣾⣿⣿⣿⣿⣿⣿⣿⣷⣌⠋⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣴⣿⣷⣄⡈⢻⣿⡟⢁⣠⣾⣿⣦
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢹⣿⣿⣿⣿⠘⣿⠃⣿⣿⣿⣿⡏⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣀⠀⠈⠛⣰⠿⣆⠛⠁⠀⡀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⣼⣿⣦⠀⠘⠛⠋⠀⣴⣿⠁⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⣀⣤⣶⣾⣿⣿⣿⣿⡇⠀⠀⠀⢸⣿⣏⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⣠⣶⣿⣿⣿⣿⣿⣿⣿⣿⠿⠿⠀⠀⠀⠾⢿⣿⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⣠⣿⣿⣿⣿⣿⣿⡿⠟⠋⣁⣠⣤⣤⡶⠶⠶⣤⣄⠈⠀⠀⠀⠀⠀⠀
⠀⠀⠀⢰⣿⣿⣮⣉⣉⣉⣤⣴⣶⣿⣿⣋⡥⠄⠀⠀⠀⠀⠉⢻⣄⠀⠀⠀⠀⠀
⠀⠀⠀⠸⣿⣿⣿⣿⣿⣿⣿⣿⣿⣟⣋⣁⣤⣀⣀⣤⣤⣤⣤⣄⣿⡄⠀⠀⠀⠀
⠀⠀⠀⠀⠙⠿⣿⣿⣿⣿⣿⣿⣿⡿⠿⠛⠋⠉⠁⠀⠀⠀⠀⠈⠛⠃⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠉⠉⠉⠉⠉⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
*/

//🦊 Made with ❤ by the devs at Kitso Mintu 🦊

// File: @openzeppelin/contracts/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: @openzeppelin/contracts/token/ERC721/IERC721Receiver.sol
pragma solidity ^0.8.0;

interface IERC721Receiver {
    /**
     * @dev Whenever an {IERC721} `tokenId` token is transferred to this contract via {IERC721-safeTransferFrom}
     * by `operator` from `from`, this function is called.
     *
     * It must return its Solidity selector to confirm the token transfer.
     * If any other value is returned or the interface is not implemented by the recipient, the transfer will be reverted.
     *
     * The selector can be obtained in Solidity with `IERC721.onERC721Received.selector`.
     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}

// File: @openzeppelin/contracts/access/Ownable.sol
pragma solidity ^0.8.0;
/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

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

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

    function _setOwner(address newOwner) private {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

pragma solidity ^0.8.9;

interface IERC721Kitsu {
    function safeTransferFrom(address from, address to, uint256 tokenId) external;
    function sendFromVault(address payable dst, uint256 amount) external;
    function availableVaultLiquidity() external view returns(uint256);
    function totalSupply() external view returns (uint256);
}

pragma solidity >=0.7.0 <0.9.0;

contract KitsuMintuRaffleContract is Ownable, IERC721Receiver {
    using SafeMath for uint256;
    using SignedSafeMath for int256;

    struct StakedToken {
        uint256 id;
        address user;
        uint256 timestamp;
        uint256[] tokenIds;
        uint256 rewards;
        uint256 totalRewards;
    }

    mapping(address => StakedToken) public stakes;
    mapping(uint256 => address) public participants;
    uint256 public participantsCount;
    uint256 public lockedRewardAmount;

    address public token;

    // event

    event Stake(address user, uint256[] tokenIds, uint256 id);
    event Unstake(address user, uint256[] tokenIds, uint256 rewards, uint256 id);
    event Raffle(address[] winners, uint256[] rewards);

    constructor(address _tokenAddress) {
        require(_tokenAddress != address(0));
        token = _tokenAddress;
    }

    function totalSupply() public view returns (uint256) {
        return IERC721Kitsu(token).totalSupply();
    }

    function availableVaultLiquidity() external view returns(uint256) {
        return IERC721Kitsu(token).availableVaultLiquidity() - lockedRewardAmount;
    }

    function stake(uint256[] calldata _tokenIds) external {
        uint256 participantId = stakes[msg.sender].id == 0 ? participantsCount++ : stakes[msg.sender].id;

        participants[participantId] = msg.sender;
        stakes[msg.sender].user = msg.sender;
        stakes[msg.sender].timestamp = block.timestamp;
        for (uint256 i = 0; i < _tokenIds.length; i++) {
            IERC721Kitsu(token).safeTransferFrom(msg.sender, address(this), _tokenIds[i]);
            stakes[msg.sender].tokenIds.push(_tokenIds[i]);
        }
        emit Stake(msg.sender, stakes[msg.sender].tokenIds, participantId);
    }

    function raffle(address[] calldata _winners, uint256[] calldata _rewards) external onlyOwner {
        require(_winners.length == _rewards.length, "Incorect raffle");
        for (uint256 i = 0; i < _winners.length; i++) {
            stakes[_winners[i]].rewards += _rewards[i];
            stakes[_winners[i]].totalRewards += _rewards[i];
            lockedRewardAmount += _rewards[i];
        }
        require(lockedRewardAmount < IERC721Kitsu(token).availableVaultLiquidity(), "Amount of total rewards exceed the vault liquidity.");
        emit Raffle(_winners, _rewards);
    }

    function unstake(uint256[] calldata _tokenIds) external {
        require(stakes[msg.sender].user == msg.sender, "Any stake");
        stakes[msg.sender].timestamp = 0; // safe reset
        for (uint256 i = 0; i < _tokenIds.length; i++) {
            uint256 index = indexOfArray(stakes[msg.sender].tokenIds, _tokenIds[i]);
            require(index < stakes[msg.sender].tokenIds.length, "Not staked");

            IERC721Kitsu(token).safeTransferFrom(address(this), msg.sender, stakes[msg.sender].tokenIds[i]);
            removeElementFromArray(stakes[msg.sender].tokenIds, index);
        }
        emit Unstake(msg.sender, stakes[msg.sender].tokenIds, stakes[msg.sender].rewards, stakes[msg.sender].id);
    }

    function claim() external {
        require(stakes[msg.sender].user == msg.sender, "Any stake");
        if (stakes[msg.sender].rewards != 0) { // if he has some rewards sendFromVault total rewarded.
            IERC721Kitsu(token).sendFromVault(payable(msg.sender), stakes[msg.sender].rewards);
            lockedRewardAmount -= stakes[msg.sender].rewards;
        }
        stakes[msg.sender].rewards = 0;
    }

    function getStakes(int256 page, int256 pageSize) external view returns (StakedToken[] memory) {
        uint256 poolLength = participantsCount;
        int256 queryStartPoolIndex = int256(poolLength).sub(pageSize.mul(page.add(1))).add(pageSize);
        require(queryStartPoolIndex >= 0, "Out of bounds");
        int256 queryEndPoolIndex = queryStartPoolIndex.sub(pageSize);
        if (queryEndPoolIndex < 0) {
            queryEndPoolIndex = 0;
        }
        int256 currentPoolIndex = queryStartPoolIndex;
        require(uint256(currentPoolIndex) <= poolLength, "Out of bounds");
        StakedToken[] memory results = new StakedToken[](uint256(currentPoolIndex - queryEndPoolIndex));
        uint256 index = 0;

        for (currentPoolIndex; currentPoolIndex > queryEndPoolIndex; currentPoolIndex--) {
            address user = participants[uint256(currentPoolIndex).sub(1)];
            results[index] = stakes[user];
            index++;
        }
        return results;
    }

    function getStake(address _user) external view returns (StakedToken memory)  {
        return stakes[_user];
    }

    function onERC721Received(
        address /* operator */,
        address /* from */,
        uint256 /* tokenId */,
        bytes calldata /* data */
    ) external pure returns (bytes4) {
        return IERC721Receiver.onERC721Received.selector;
    }

    function indexOfArray(uint[] storage _array, uint _element) internal view returns (uint) {
        for (uint i = 0; i < _array.length; i++) {
            if (_array[i] == _element) {
                return i;
            }
        }
        return _array.length;
    }

    function removeElementFromArray(uint[] storage _array, uint _index) internal {
        require(_index < _array.length);
        for (uint i = _index; i < _array.length - 1; i++) {
            _array[i] = _array[i + 1];
        }
        _array.pop();
    }

}
// File: /contracts/libs/SignedSafeMath.sol



// SPDX-License-Identifier: MIT

/**
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⣀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣀⡀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣾⠙⠻⢶⣄⡀⠀⠀⠀⢀⣤⠶⠛⠛⡇⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢹⣇⠀⠀⣙⣿⣦⣤⣴⣿⣁⠀⠀⣸⠇⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠙⣡⣾⣿⣿⣿⣿⣿⣿⣿⣷⣌⠋⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣴⣿⣷⣄⡈⢻⣿⡟⢁⣠⣾⣿⣦
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢹⣿⣿⣿⣿⠘⣿⠃⣿⣿⣿⣿⡏⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣀⠀⠈⠛⣰⠿⣆⠛⠁⠀⡀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⣼⣿⣦⠀⠘⠛⠋⠀⣴⣿⠁⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⣀⣤⣶⣾⣿⣿⣿⣿⡇⠀⠀⠀⢸⣿⣏⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⣠⣶⣿⣿⣿⣿⣿⣿⣿⣿⠿⠿⠀⠀⠀⠾⢿⣿⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⣠⣿⣿⣿⣿⣿⣿⡿⠟⠋⣁⣠⣤⣤⡶⠶⠶⣤⣄⠈⠀⠀⠀⠀⠀⠀
⠀⠀⠀⢰⣿⣿⣮⣉⣉⣉⣤⣴⣶⣿⣿⣋⡥⠄⠀⠀⠀⠀⠉⢻⣄⠀⠀⠀⠀⠀
⠀⠀⠀⠸⣿⣿⣿⣿⣿⣿⣿⣿⣿⣟⣋⣁⣤⣀⣀⣤⣤⣤⣤⣄⣿⡄⠀⠀⠀⠀
⠀⠀⠀⠀⠙⠿⣿⣿⣿⣿⣿⣿⣿⡿⠿⠛⠋⠉⠁⠀⠀⠀⠀⠈⠛⠃⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠉⠉⠉⠉⠉⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
*/

//🦊 Made with ❤ by the devs at Kitso Mintu 🦊

// OpenZeppelin Contracts v4.4.1 (utils/math/SignedSafeMath.sol)
pragma solidity ^0.8.0;

library SignedSafeMath {
    function mul(int256 a, int256 b) internal pure returns (int256) {
        return a * b;
    }
    function div(int256 a, int256 b) internal pure returns (int256) {
        return a / b;
    }
    function sub(int256 a, int256 b) internal pure returns (int256) {
        return a - b;
    }
    function add(int256 a, int256 b) internal pure returns (int256) {
        return a + b;
    }
}
// File: /contracts/libs/SafeMath.sol



// SPDX-License-Identifier: MIT

/**
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⣀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣀⡀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣾⠙⠻⢶⣄⡀⠀⠀⠀⢀⣤⠶⠛⠛⡇⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢹⣇⠀⠀⣙⣿⣦⣤⣴⣿⣁⠀⠀⣸⠇⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠙⣡⣾⣿⣿⣿⣿⣿⣿⣿⣷⣌⠋⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣴⣿⣷⣄⡈⢻⣿⡟⢁⣠⣾⣿⣦
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢹⣿⣿⣿⣿⠘⣿⠃⣿⣿⣿⣿⡏⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣀⠀⠈⠛⣰⠿⣆⠛⠁⠀⡀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢀⣼⣿⣦⠀⠘⠛⠋⠀⣴⣿⠁⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠀⠀⣀⣤⣶⣾⣿⣿⣿⣿⡇⠀⠀⠀⢸⣿⣏⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⣠⣶⣿⣿⣿⣿⣿⣿⣿⣿⠿⠿⠀⠀⠀⠾⢿⣿⠀⠀⠀⠀⠀⠀
⠀⠀⠀⠀⣠⣿⣿⣿⣿⣿⣿⡿⠟⠋⣁⣠⣤⣤⡶⠶⠶⣤⣄⠈⠀⠀⠀⠀⠀⠀
⠀⠀⠀⢰⣿⣿⣮⣉⣉⣉⣤⣴⣶⣿⣿⣋⡥⠄⠀⠀⠀⠀⠉⢻⣄⠀⠀⠀⠀⠀
⠀⠀⠀⠸⣿⣿⣿⣿⣿⣿⣿⣿⣿⣟⣋⣁⣤⣀⣀⣤⣤⣤⣤⣄⣿⡄⠀⠀⠀⠀
⠀⠀⠀⠀⠙⠿⣿⣿⣿⣿⣿⣿⣿⡿⠿⠛⠋⠉⠁⠀⠀⠀⠀⠈⠛⠃⠀⠀⠀⠀
⠀⠀⠀⠀⠀⠀⠀⠉⠉⠉⠉⠉⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
*/

//🦊 Made with ❤ by the devs at Kitsu Mintu 🦊

pragma solidity ^0.8.0;
/**
 * @dev Wrappers over Solidity's arithmetic operations.
 *
 * NOTE: `SafeMath` is generally not needed starting with Solidity 0.8, since the compiler
 * now has built in overflow checking.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            uint256 c = a + b;
            if (c < a) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b > a) return (false, 0);
            return (true, a - b);
        }
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
            // benefit is lost if 'b' is also tested.
            // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
            if (a == 0) return (true, 0);
            uint256 c = a * b;
            if (c / a != b) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the division of two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a / b);
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a % b);
        }
    }

    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        return a + b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return a - b;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        return a * b;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator.
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return a % b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {trySub}.
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        unchecked {
            require(b <= a, errorMessage);
            return a - b;
        }
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a / b;
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting with custom message when dividing by zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryMod}.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a % b;
        }
    }
}