// File: contracts/BondlyLaunchpad.sol



// SPDX-License-Identifier: UNLICENSED

pragma solidity ^0.7.3;

/////////////////////////////////////////////////
//  ____                        _   _          //
// | __ )    ___    _ __     __| | | |  _   _  //
// |  _ \   / _ \  | '_ \   / _` | | | | | | | //
// | |_) | | (_) | | | | | | (_| | | | | |_| | //
// |____/   \___/  |_| |_|  \__,_| |_|  \__, | //
//                                      |___/  //
/////////////////////////////////////////////////

import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/utils/Strings.sol";
import "@openzeppelin/contracts/utils/Address.sol";
import "@openzeppelin/contracts/math/SafeMath.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC1155/IERC1155.sol";
import "@openzeppelin/contracts/token/ERC1155/IERC1155MetadataURI.sol";

contract BondlyLaunchPad is Ownable {
    using Strings for string;
    using SafeMath for uint256;
    using Address for address;

    uint256 public _currentCardId = 0;
    address payable public _salesperson;
    uint256 public _limitPerWallet;
    bool public _saleStarted = false;

    struct Card {
        uint256 cardId;
        uint256 tokenId;
        uint256 totalAmount;
        uint256 currentAmount;
        uint256 basePrice;
        uint256[] times;
        uint8[] tiers;
        address contractAddress;
        bool isFinished;
    }

    struct History {
        mapping(uint256 => mapping(address => uint8)) purchasedHistories; // tokenId -> wallet -> amount
    }

    // Events
    event CreateCard(
        address indexed _from,
        uint256 _cardId,
        address indexed _contractAddress,
        uint256 _tokenId,
        uint256 _totalAmount,
        uint256 _basePrice
    );

    event PurchaseCard(address indexed _from, uint256 _cardId, uint256 _amount);
    event CardChanged(uint256 _cardId);

    mapping(uint256 => Card) public _cards;
    mapping(address => bool) public _blacklist;
    mapping(uint256 => mapping(address => uint8)) public _whitelist; // tokenId -> wallet -> whitelistLevel

    // whitelist level      | Priority
    // 0: Not available     |    /\
    // 1: selected winners  |    ||
    // 2: bronze            |    ||
    // 3: silver            |    ||
    // 4: gold              |    ||
    // 5: platinum          |    ||

    mapping(address => History) private _history;

    constructor() {
        _salesperson = msg.sender;
        _limitPerWallet = 1;
    }

    function setLimitPerWallet(uint256 limit) external onlyOwner {
        _limitPerWallet = limit;
    }

    function setSalesPerson(address payable newSalesPerson) external onlyOwner {
        _salesperson = newSalesPerson;
    }

    function startSale() external onlyOwner {
        _saleStarted = true;
    }

    function stopSale() external onlyOwner {
        _saleStarted = false;
    }

    function createCard(
        address _contractAddress,
        uint256 _tokenId,
        uint256 _totalAmount,
        uint256 _basePrice
    ) external onlyOwner {
        IERC1155 _contract = IERC1155(_contractAddress);
        require(
            _contract.balanceOf(_salesperson, _tokenId) >= _totalAmount,
            "Initial supply cannot be more than available supply"
        );
        require(
            _contract.isApprovedForAll(_salesperson, address(this)) == true,
            "Contract must be whitelisted by owner"
        );
        uint256 _id = _getNextCardID();
        _incrementCardId();
        Card memory _newCard;
        _newCard.cardId = _id;
        _newCard.contractAddress = _contractAddress;
        _newCard.tokenId = _tokenId;
        _newCard.totalAmount = _totalAmount;
        _newCard.currentAmount = _totalAmount;
        _newCard.basePrice = _basePrice;
        _newCard.isFinished = false;

        _cards[_id] = _newCard;
        emit CreateCard(
            msg.sender,
            _id,
            _contractAddress,
            _tokenId,
            _totalAmount,
            _basePrice
        );
    }

    function isEligbleToBuy(uint256 _cardId) public view returns (uint256) {
        if (_blacklist[msg.sender] == true) return 0;

        if (_saleStarted == false) return 0;

        Card memory _currentCard = _cards[_cardId];

        if (_currentCard.times.length == 0) return 0;

        for (uint256 i = 0; i < _currentCard.times.length; i++) {
            if (
                block.timestamp >= _currentCard.times[i] &&
                _whitelist[_cardId][msg.sender] == _currentCard.tiers[i]
            ) {
                History storage _currentHistory =
                    _history[_currentCard.contractAddress];
                uint256 _currentBoughtAmount =
                    _currentHistory.purchasedHistories[_currentCard.tokenId][
                        msg.sender
                    ];

                if (_currentBoughtAmount >= _limitPerWallet) return 0;

                if (
                    _currentCard.currentAmount <=
                    _limitPerWallet.sub(_currentBoughtAmount)
                ) return _currentCard.currentAmount;

                return _limitPerWallet.sub(_currentBoughtAmount);
            }
        }

        return 0;
    }

    function purchaseNFT(uint256 _cardId, uint256 _amount) external payable {
        require(_blacklist[msg.sender] == false, "you are blocked");

        require(_saleStarted == true, "Sale stopped");

        Card memory _currentCard = _cards[_cardId];
        require(_currentCard.isFinished == false, "Card is finished");

        uint8 currentTier = _whitelist[_cardId][msg.sender];
        require(currentTier != 0, "you are not whitelisted");

        uint256 startTime;
        for (uint256 i = 0; i < _currentCard.tiers.length; i++) {
            if (_currentCard.tiers[i] == currentTier) {
                startTime = _currentCard.times[i];
            }
        }

        require(
            startTime != 0 && startTime <= block.timestamp,
            "wait for sale start"
        );

        IERC1155 _nftContract = IERC1155(_currentCard.contractAddress);
        require(
            _currentCard.currentAmount >= _amount,
            "Order exceeds the max number of available NFTs"
        );

        History storage _currentHistory =
            _history[_currentCard.contractAddress];
        uint256 _currentBoughtAmount =
            _currentHistory.purchasedHistories[_currentCard.tokenId][
                msg.sender
            ];

        require(
            _currentBoughtAmount < _limitPerWallet,
            "Order exceeds the max limit of NFTs per wallet"
        );

        uint256 availableAmount = _limitPerWallet.sub(_currentBoughtAmount);
        if (availableAmount > _amount) {
            availableAmount = _amount;
        }

        uint256 _price = _currentCard.basePrice.mul(availableAmount);

        require(msg.value >= _price, "Not enough funds to purchase");
        uint256 overPrice = msg.value - _price;
        _salesperson.transfer(_price);

        if (overPrice > 0) msg.sender.transfer(overPrice);

        _nftContract.safeTransferFrom(
            _salesperson,
            msg.sender,
            _currentCard.tokenId,
            availableAmount,
            ""
        );
        _cards[_cardId].currentAmount = _cards[_cardId].currentAmount.sub(
            availableAmount
        );

        _currentHistory.purchasedHistories[_currentCard.tokenId][
            msg.sender
        ] = uint8(_currentBoughtAmount.add(availableAmount));

        emit PurchaseCard(msg.sender, _cardId, availableAmount);
    }

    function _getNextCardID() private view returns (uint256) {
        return _currentCardId.add(1);
    }

    function _incrementCardId() private {
        _currentCardId++;
    }

    function cancelCard(uint256 _cardId) external onlyOwner {
        _cards[_cardId].isFinished = true;

        emit CardChanged(_cardId);
    }

    function setTimes(
        uint256 _cardId,
        uint8 _tier,
        uint256 _finalTime
    ) external onlyOwner {
        Card storage _currentCard = _cards[_cardId];

        for (uint256 i = 0; i < _currentCard.tiers.length; i++) {
            if (_currentCard.tiers[i] == _tier) {
                _currentCard.times[i] = _finalTime;
                emit CardChanged(_cardId);
                return;
            }
        }

        _currentCard.tiers.push(_tier);
        _currentCard.times.push(_finalTime);
        emit CardChanged(_cardId);
    }

    function resumeCard(uint256 _cardId) external onlyOwner {
        _cards[_cardId].isFinished = false;

        emit CardChanged(_cardId);
    }

    function setCardPrice(uint256 _cardId, uint256 _newPrice)
        external
        onlyOwner
        returns (bool)
    {
        _cards[_cardId].basePrice = _newPrice;

        emit CardChanged(_cardId);
        return true;
    }

    function addBlackListAddress(address addr) external onlyOwner {
        _blacklist[addr] = true;
    }

    function batchAddBlackListAddress(address[] calldata addr)
        external
        onlyOwner
    {
        for (uint256 i = 0; i < addr.length; i++) {
            _blacklist[addr[i]] = true;
        }
    }

    function removeBlackListAddress(address addr) external onlyOwner {
        _blacklist[addr] = false;
    }

    function batchRemoveBlackListAddress(address[] calldata addr)
        external
        onlyOwner
    {
        for (uint256 i = 0; i < addr.length; i++) {
            _blacklist[addr[i]] = false;
        }
    }

    function addWhiteListAddress(
        uint256 _cardId,
        address _addr,
        uint8 _tier
    ) external onlyOwner {
        _whitelist[_cardId][_addr] = _tier;
    }

    function batchAddWhiteListAddress(
        uint256 _cardId,
        address[] calldata _addr,
        uint8 _tier
    ) external onlyOwner {
        for (uint256 i = 0; i < _addr.length; i++) {
            _whitelist[_cardId][_addr[i]] = _tier;
        }
    }

    function isCardCompleted(uint256 _cardId) public view returns (bool) {
        return _cards[_cardId].isFinished;
    }

    function isCardFree(uint256 _cardId) public view returns (bool) {
        return _cards[_cardId].basePrice == 0;
    }

    function getCardContract(uint256 _cardId) public view returns (address) {
        return _cards[_cardId].contractAddress;
    }

    function getCardTokenId(uint256 _cardId) public view returns (uint256) {
        return _cards[_cardId].tokenId;
    }

    function getCardTime(uint256 _cardId)
        public
        view
        returns (uint256[] memory)
    {
        return _cards[_cardId].times;
    }

    function getCardTotalAmount(uint256 _cardId) public view returns (uint256) {
        return _cards[_cardId].totalAmount;
    }

    function getCardCurrentAmount(uint256 _cardId)
        public
        view
        returns (uint256)
    {
        return _cards[_cardId].currentAmount;
    }

    function getAllCardsPerContract(address _contractAddr)
        public
        view
        returns (uint256[] memory, uint256[] memory)
    {
        uint256 count;
        for (uint256 i = 1; i <= _currentCardId; i++) {
            if (_cards[i].contractAddress == _contractAddr) {
                count++;
            }
        }

        uint256[] memory cardIds = new uint256[](count);
        uint256[] memory tokenIds = new uint256[](count);
        count = 0;

        for (uint256 i = 1; i <= _currentCardId; i++) {
            if (_cards[i].contractAddress == _contractAddr) {
                cardIds[count] = i;
                tokenIds[count] = _cards[i].tokenId;
                count++;
            }
        }

        return (cardIds, tokenIds);
    }

    function getActiveCardsPerContract(address _contractAddr)
        public
        view
        returns (uint256[] memory, uint256[] memory)
    {
        uint256 count;
        for (uint256 i = 1; i <= _currentCardId; i++) {
            if (
                _cards[i].contractAddress == _contractAddr &&
                _cards[i].isFinished == false
            ) {
                count++;
            }
        }

        uint256[] memory cardIds = new uint256[](count);
        uint256[] memory tokenIds = new uint256[](count);
        count = 0;

        for (uint256 i = 1; i <= _currentCardId; i++) {
            if (
                _cards[i].contractAddress == _contractAddr &&
                _cards[i].isFinished == false
            ) {
                cardIds[count] = i;
                tokenIds[count] = _cards[i].tokenId;
                count++;
            }
        }

        return (cardIds, tokenIds);
    }

    function getClosedCardsPerContract(address _contractAddr)
        public
        view
        returns (uint256[] memory, uint256[] memory)
    {
        uint256 count;
        for (uint256 i = 1; i <= _currentCardId; i++) {
            if (
                _cards[i].contractAddress == _contractAddr &&
                _cards[i].isFinished
            ) {
                count++;
            }
        }

        uint256[] memory cardIds = new uint256[](count);
        uint256[] memory tokenIds = new uint256[](count);
        count = 0;

        for (uint256 i = 1; i <= _currentCardId; i++) {
            if (
                _cards[i].contractAddress == _contractAddr &&
                _cards[i].isFinished
            ) {
                cardIds[count] = i;
                tokenIds[count] = _cards[i].tokenId;
                count++;
            }
        }

        return (cardIds, tokenIds);
    }

    function getCardBasePrice(uint256 _cardId) public view returns (uint256) {
        return _cards[_cardId].basePrice;
    }

    function getCardURL(uint256 _cardId) public view returns (string memory) {
        return
            IERC1155MetadataURI(_cards[_cardId].contractAddress).uri(
                _cards[_cardId].tokenId
            );
    }

    function collect(address _token) external onlyOwner {
        if (_token == address(0)) {
            msg.sender.transfer(address(this).balance);
        } else {
            uint256 amount = IERC20(_token).balanceOf(address(this));
            IERC20(_token).transfer(msg.sender, amount);
        }
    }
}

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



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <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 () internal {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

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



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev String operations.
 */
library Strings {
    /**
     * @dev Converts a `uint256` to its ASCII `string` representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        // Inspired by OraclizeAPI's implementation - MIT licence
        // https://github.com/oraclize/ethereum-api/blob/b42146b063c7d6ee1358846c198246239e9360e8/oraclizeAPI_0.4.25.sol

        if (value == 0) {
            return "0";
        }
        uint256 temp = value;
        uint256 digits;
        while (temp != 0) {
            digits++;
            temp /= 10;
        }
        bytes memory buffer = new bytes(digits);
        uint256 index = digits - 1;
        temp = value;
        while (temp != 0) {
            buffer[index--] = bytes1(uint8(48 + temp % 10));
            temp /= 10;
        }
        return string(buffer);
    }
}

// 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: @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/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/token/ERC1155/IERC1155.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.2 <0.8.0;

import "../../introspection/IERC165.sol";

/**
 * @dev Required interface of an ERC1155 compliant contract, as defined in the
 * https://eips.ethereum.org/EIPS/eip-1155[EIP].
 *
 * _Available since v3.1._
 */
interface IERC1155 is IERC165 {
    /**
     * @dev Emitted when `value` tokens of token type `id` are transferred from `from` to `to` by `operator`.
     */
    event TransferSingle(address indexed operator, address indexed from, address indexed to, uint256 id, uint256 value);

    /**
     * @dev Equivalent to multiple {TransferSingle} events, where `operator`, `from` and `to` are the same for all
     * transfers.
     */
    event TransferBatch(address indexed operator, address indexed from, address indexed to, uint256[] ids, uint256[] values);

    /**
     * @dev Emitted when `account` grants or revokes permission to `operator` to transfer their tokens, according to
     * `approved`.
     */
    event ApprovalForAll(address indexed account, address indexed operator, bool approved);

    /**
     * @dev Emitted when the URI for token type `id` changes to `value`, if it is a non-programmatic URI.
     *
     * If an {URI} event was emitted for `id`, the standard
     * https://eips.ethereum.org/EIPS/eip-1155#metadata-extensions[guarantees] that `value` will equal the value
     * returned by {IERC1155MetadataURI-uri}.
     */
    event URI(string value, uint256 indexed id);

    /**
     * @dev Returns the amount of tokens of token type `id` owned by `account`.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     */
    function balanceOf(address account, uint256 id) external view returns (uint256);

    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {balanceOf}.
     *
     * Requirements:
     *
     * - `accounts` and `ids` must have the same length.
     */
    function balanceOfBatch(address[] calldata accounts, uint256[] calldata ids) external view returns (uint256[] memory);

    /**
     * @dev Grants or revokes permission to `operator` to transfer the caller's tokens, according to `approved`,
     *
     * Emits an {ApprovalForAll} event.
     *
     * Requirements:
     *
     * - `operator` cannot be the caller.
     */
    function setApprovalForAll(address operator, bool approved) external;

    /**
     * @dev Returns true if `operator` is approved to transfer ``account``'s tokens.
     *
     * See {setApprovalForAll}.
     */
    function isApprovedForAll(address account, address operator) external view returns (bool);

    /**
     * @dev Transfers `amount` tokens of token type `id` from `from` to `to`.
     *
     * Emits a {TransferSingle} event.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - If the caller is not `from`, it must be have been approved to spend ``from``'s tokens via {setApprovalForAll}.
     * - `from` must have a balance of tokens of type `id` of at least `amount`.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155Received} and return the
     * acceptance magic value.
     */
    function safeTransferFrom(address from, address to, uint256 id, uint256 amount, bytes calldata data) external;

    /**
     * @dev xref:ROOT:erc1155.adoc#batch-operations[Batched] version of {safeTransferFrom}.
     *
     * Emits a {TransferBatch} event.
     *
     * Requirements:
     *
     * - `ids` and `amounts` must have the same length.
     * - If `to` refers to a smart contract, it must implement {IERC1155Receiver-onERC1155BatchReceived} and return the
     * acceptance magic value.
     */
    function safeBatchTransferFrom(address from, address to, uint256[] calldata ids, uint256[] calldata amounts, bytes calldata data) external;
}

// File: @openzeppelin/contracts/token/ERC1155/IERC1155MetadataURI.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.2 <0.8.0;

import "./IERC1155.sol";

/**
 * @dev Interface of the optional ERC1155MetadataExtension interface, as defined
 * in the https://eips.ethereum.org/EIPS/eip-1155#metadata-extensions[EIP].
 *
 * _Available since v3.1._
 */
interface IERC1155MetadataURI is IERC1155 {
    /**
     * @dev Returns the URI for token type `id`.
     *
     * If the `\{id\}` substring is present in the URI, it must be replaced by
     * clients with the actual token type ID.
     */
    function uri(uint256 id) external view returns (string memory);
}

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



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

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

    function _msgData() internal view virtual returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

// File: @openzeppelin/contracts/introspection/IERC165.sol



// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

/**
 * @dev Interface of the ERC165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[EIP].
 *
 * Implementers can declare support of contract interfaces, which can then be
 * queried by others ({ERC165Checker}).
 *
 * For an implementation, see {ERC165}.
 */
interface IERC165 {
    /**
     * @dev Returns true if this contract implements the interface defined by
     * `interfaceId`. See the corresponding
     * https://eips.ethereum.org/EIPS/eip-165#how-interfaces-are-identified[EIP section]
     * to learn more about how these ids are created.
     *
     * This function call must use less than 30 000 gas.
     */
    function supportsInterface(bytes4 interfaceId) external view returns (bool);
}