NFTPurchase

{{
  "language": "Solidity",
  "sources": {
    "nftSale.sol": {
      "content": "// SPDX-License-Identifier: MIT
pragma solidity ^0.8.30;

import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/utils/ReentrancyGuard.sol";
import "@openzeppelin/contracts/utils/Pausable.sol";

/**
 * @title NFTPurchase
 * @dev Contract for purchasing Solana NFTs with USDC/USDT on EVM chains
 * @author Cross-Chain NFT System
 */
contract NFTPurchase is Ownable, ReentrancyGuard, Pausable {
    // Fixed price: 100 USDC/USDT (6 decimals)
    uint256 public NFT_PRICE = 100 * 10 ** 6;

    // Supported stablecoins
    address public immutable USDC;
    address public immutable USDT;

    // Purchase tracking
    uint256 private _purchaseCounter;

    struct Purchase {
        uint256 id;
        address buyer;
        address token;
        uint256 amount;
        string solanaAddress;
        string metadataUri;
        uint256 timestamp;
        bool refunded;
    }

    // Storage
    mapping(uint256 => Purchase) public purchases;
    mapping(address => uint256[]) public userPurchases;
    mapping(address => bool) public supportedTokens;

    // Events
    event NFTPurchased(
        uint256 indexed purchaseId,
        address indexed buyer,
        address indexed token,
        string solanaAddress,
        string metadataUri,
        uint256 amount,
        uint256 timestamp
    );

    event PurchaseRefunded(
        uint256 indexed purchaseId,
        address indexed buyer,
        address token,
        uint256 amount
    );

    event FundsWithdrawn(
        address indexed token,
        address indexed to,
        uint256 amount
    );

    event TokenSupportUpdated(address indexed token, bool supported);

    event PriceChanged(uint256 oldPrice, uint256 newPrice, uint256 timestamp);

    constructor(address _usdc, address _usdt) Ownable(msg.sender)   {
        require(_usdc != address(0), "Invalid USDC address");
        require(_usdt != address(0), "Invalid USDT address");

        USDC = _usdc;
        USDT = _usdt;

        // Mark tokens as supported
        supportedTokens[_usdc] = true;
        supportedTokens[_usdt] = true;

        emit TokenSupportUpdated(_usdc, true);
        emit TokenSupportUpdated(_usdt, true);
    }

    /**
     * @dev Purchase an NFT with USDC or USDT
     * @param token Address of the token to pay with (USDC or USDT)
     * @param solanaAddress Solana wallet address for NFT delivery
     * @param metadataUri IPFS URI for NFT metadata
     */
    function purchaseNFT(
        address token,
        string calldata solanaAddress,
        string calldata metadataUri
    ) external nonReentrant whenNotPaused {
        require(supportedTokens[token], "Token not supported");
        require(bytes(solanaAddress).length > 0, "Solana address required");
        require(bytes(metadataUri).length > 0, "Metadata URI required");
        require(
            _isValidSolanaAddress(solanaAddress),
            "Invalid Solana address format"
        );

        // Transfer tokens from buyer
        IERC20(token).transferFrom(msg.sender, address(this), NFT_PRICE);

        // Create purchase record
        uint256 purchaseId = ++_purchaseCounter;

        purchases[purchaseId] = Purchase({
            id: purchaseId,
            buyer: msg.sender,
            token: token,
            amount: NFT_PRICE,
            solanaAddress: solanaAddress,
            metadataUri: metadataUri,
            timestamp: block.timestamp,
            refunded: false
        });

        userPurchases[msg.sender].push(purchaseId);

        emit NFTPurchased(
            purchaseId,
            msg.sender,
            token,
            solanaAddress,
            metadataUri,
            NFT_PRICE,
            block.timestamp
        );
    }

    function changePrice(uint256 newPrice) external onlyOwner {
        require(newPrice > 0, "Price should be > 0");

        uint256 oldPrice = NFT_PRICE;
        NFT_PRICE = newPrice * 10 ** 6; // Convert to 6 decimals for USDC/USDT

        emit PriceChanged(oldPrice, NFT_PRICE, block.timestamp);
    }

    /**
     * @dev Refund a purchase (owner only, for emergency situations)
     * @param purchaseId ID of the purchase to refund
     */
    function refundPurchase(uint256 purchaseId) external onlyOwner {
        Purchase storage purchase = purchases[purchaseId];
        require(purchase.id != 0, "Purchase not found");
        require(!purchase.refunded, "Already refunded");

        purchase.refunded = true;

        // Transfer tokens back to buyer
        IERC20(purchase.token).transfer(purchase.buyer, purchase.amount);

        emit PurchaseRefunded(
            purchaseId,
            purchase.buyer,
            purchase.token,
            purchase.amount
        );
    }

    /**
     * @dev Withdraw collected funds (owner only)
     * @param token Token address to withdraw
     * @param to Address to send funds to
     */
    function withdrawFunds(address token, address to) external onlyOwner {
        require(to != address(0), "Invalid recipient");
        require(supportedTokens[token], "Token not supported");

        uint256 balance = IERC20(token).balanceOf(address(this));
        require(balance > 0, "No funds to withdraw");

        IERC20(token).transfer(to, balance);

        emit FundsWithdrawn(token, to, balance);
    }

    /**
     * @dev Update token support status (owner only)
     * @param token Token address to update
     * @param supported Whether the token should be supported
     */
    function setSupportedToken(
        address token,
        bool supported
    ) external onlyOwner {
        require(token != address(0), "Invalid token address");
        supportedTokens[token] = supported;
        emit TokenSupportUpdated(token, supported);
    }

    /**
     * @dev Pause the contract (owner only)
     */
    function pause() external onlyOwner {
        _pause();
    }

    /**
     * @dev Unpause the contract (owner only)
     */
    function unpause() external onlyOwner {
        _unpause();
    }

    /**
     * @dev Get user's purchase history
     * @param user Address of the user
     * @return Array of purchase IDs
     */
    function getUserPurchases(
        address user
    ) external view returns (uint256[] memory) {
        return userPurchases[user];
    }

    /**
     * @dev Get total number of purchases
     * @return Total purchase count
     */
    function getTotalPurchases() external view returns (uint256) {
        return _purchaseCounter;
    }

    /**
     * @dev Get contract balance for a specific token
     * @param token Token address to check
     * @return Token balance
     */
    function getTokenBalance(address token) external view returns (uint256) {
        return IERC20(token).balanceOf(address(this));
    }

    /**
     * @dev Basic Solana address validation (44 chars, base58)
     * @param addr Solana address string to validate
     * @return true if format appears valid
     */
    function _isValidSolanaAddress(
        string memory addr
    ) private pure returns (bool) {
        bytes memory b = bytes(addr);

        // Check length (Solana addresses are 44 characters)
        if (b.length != 44) {
            return false;
        }

        // Basic character validation (alphanumeric base58)
        for (uint i = 0; i < b.length; i++) {
            bytes1 char = b[i];
            if (
                !((char >= "1" && char <= "9") || // 1-9
                    (char >= "A" && char <= "H") || // A-H
                    (char >= "J" && char <= "N") || // J-N (no I)
                    (char >= "P" && char <= "Z") || // P-Z (no O)
                    (char >= "a" && char <= "k") || // a-k
                    (char >= "m" && char <= "z")) // m-z (no l)
            ) {
                return false;
            }
        }

        return true;
    }
}"
    },
    "@openzeppelin/contracts/utils/Pausable.sol": {
      "content": "// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.3.0) (utils/Pausable.sol)

pragma solidity ^0.8.20;

import {Context} from "../utils/Context.sol";

/**
 * @dev Contract module which allows children to implement an emergency stop
 * mechanism that can be triggered by an authorized account.
 *
 * This module is used through inheritance. It will make available the
 * modifiers `whenNotPaused` and `whenPaused`, which can be applied to
 * the functions of your contract. Note that they will not be pausable by
 * simply including this module, only once the modifiers are put in place.
 */
abstract contract Pausable is Context {
    bool private _paused;

    /**
     * @dev Emitted when the pause is triggered by `account`.
     */
    event Paused(address account);

    /**
     * @dev Emitted when the pause is lifted by `account`.
     */
    event Unpaused(address account);

    /**
     * @dev The operation failed because the contract is paused.
     */
    error EnforcedPause();

    /**
     * @dev The operation failed because the contract is not paused.
     */
    error ExpectedPause();

    /**
     * @dev Modifier to make a function callable only when the contract is not paused.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    modifier whenNotPaused() {
        _requireNotPaused();
        _;
    }

    /**
     * @dev Modifier to make a function callable only when the contract is paused.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    modifier whenPaused() {
        _requirePaused();
        _;
    }

    /**
     * @dev Returns true if the contract is paused, and false otherwise.
     */
    function paused() public view virtual returns (bool) {
        return _paused;
    }

    /**
     * @dev Throws if the contract is paused.
     */
    function _requireNotPaused() internal view virtual {
        if (paused()) {
            revert EnforcedPause();
        }
    }

    /**
     * @dev Throws if the contract is not paused.
     */
    function _requirePaused() internal view virtual {
        if (!paused()) {
            revert ExpectedPause();
        }
    }

    /**
     * @dev Triggers stopped state.
     *
     * Requirements:
     *
     * - The contract must not be paused.
     */
    function _pause() internal virtual whenNotPaused {
        _paused = true;
        emit Paused(_msgSender());
    }

    /**
     * @dev Returns to normal state.
     *
     * Requirements:
     *
     * - The contract must be paused.
     */
    function _unpause() internal virtual whenPaused {
        _paused = false;
        emit Unpaused(_msgSender());
    }
}
"
    },
    "@openzeppelin/contracts/utils/ReentrancyGuard.sol": {
      "content": "// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.1.0) (utils/ReentrancyGuard.sol)

pragma solidity ^0.8.20;

/**
 * @dev Contract module that helps prevent reentrant calls to a function.
 *
 * Inheriting from `ReentrancyGuard` will make the {nonReentrant} modifier
 * available, which can be applied to functions to make sure there are no nested
 * (reentrant) calls to them.
 *
 * Note that because there is a single `nonReentrant` guard, functions marked as
 * `nonReentrant` may not call one another. This can be worked around by making
 * those functions `private`, and then adding `external` `nonReentrant` entry
 * points to them.
 *
 * TIP: If EIP-1153 (transient storage) is available on the chain you're deploying at,
 * consider using {ReentrancyGuardTransient} instead.
 *
 * TIP: If you would like to learn more about reentrancy and alternative ways
 * to protect against it, check out our blog post
 * https://blog.openzeppelin.com/reentrancy-after-istanbul/[Reentrancy After Istanbul].
 */
abstract contract ReentrancyGuard {
    // Booleans are more expensive than uint256 or any type that takes up a full
    // word because each write operation emits an extra SLOAD to first read the
    // slot's contents, replace the bits taken up by the boolean, and then write
    // back. This is the compiler's defense against contract upgrades and
    // pointer aliasing, and it cannot be disabled.

    // The values being non-zero value makes deployment a bit more expensive,
    // but in exchange the refund on every call to nonReentrant will be lower in
    // amount. Since refunds are capped to a percentage of the total
    // transaction's gas, it is best to keep them low in cases like this one, to
    // increase the likelihood of the full refund coming into effect.
    uint256 private constant NOT_ENTERED = 1;
    uint256 private constant ENTERED = 2;

    uint256 private _status;

    /**
     * @dev Unauthorized reentrant call.
     */
    error ReentrancyGuardReentrantCall();

    constructor() {
        _status = NOT_ENTERED;
    }

    /**
     * @dev Prevents a contract from calling itself, directly or indirectly.
     * Calling a `nonReentrant` function from another `nonReentrant`
     * function is not supported. It is possible to prevent this from happening
     * by making the `nonReentrant` function external, and making it call a
     * `private` function that does the actual work.
     */
    modifier nonReentrant() {
        _nonReentrantBefore();
        _;
        _nonReentrantAfter();
    }

    function _nonReentrantBefore() private {
        // On the first call to nonReentrant, _status will be NOT_ENTERED
        if (_status == ENTERED) {
            revert ReentrancyGuardReentrantCall();
        }

        // Any calls to nonReentrant after this point will fail
        _status = ENTERED;
    }

    function _nonReentrantAfter() private {
        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _status = NOT_ENTERED;
    }

    /**
     * @dev Returns true if the reentrancy guard is currently set to "entered", which indicates there is a
     * `nonReentrant` function in the call stack.
     */
    function _reentrancyGuardEntered() internal view returns (bool) {
        return _status == ENTERED;
    }
}
"
    },
    "@openzeppelin/contracts/access/Ownable.sol": {
      "content": "// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (access/Ownable.sol)

pragma solidity ^0.8.20;

import {Context} from "../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.
 *
 * The initial owner is set to the address provided by the deployer. 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;

    /**
     * @dev The caller account is not authorized to perform an operation.
     */
    error OwnableUnauthorizedAccount(address account);

    /**
     * @dev The owner is not a valid owner account. (eg. `address(0)`)
     */
    error OwnableInvalidOwner(address owner);

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

    /**
     * @dev Initializes the contract setting the address provided by the deployer as the initial owner.
     */
    constructor(address initialOwner) {
        if (initialOwner == address(0)) {
            revert OwnableInvalidOwner(address(0));
        }
        _transferOwnership(initialOwner);
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

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

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        if (owner() != _msgSender()) {
            revert OwnableUnauthorizedAccount(_msgSender());
        }
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby disabling 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 {
        if (newOwner == address(0)) {
            revert OwnableInvalidOwner(address(0));
        }
        _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);
    }
}
"
    },
    "@openzeppelin/contracts/token/ERC20/IERC20.sol": {
      "content": "// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.4.0) (token/ERC20/IERC20.sol)

pragma solidity >=0.4.16;

/**
 * @dev Interface of the ERC-20 standard as defined in the ERC.
 */
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 value of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

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

    /**
     * @dev Moves a `value` amount of 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 value) 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 a `value` amount of tokens 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 value) external returns (bool);

    /**
     * @dev Moves a `value` amount of tokens from `from` to `to` using the
     * allowance mechanism. `value` 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 value) external returns (bool);
}
"
    },
    "@openzeppelin/contracts/utils/Context.sol": {
      "content": "// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.1) (utils/Context.sol)

pragma solidity ^0.8.20;

/**
 * @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;
    }

    function _contextSuffixLength() internal view virtual returns (uint256) {
        return 0;
    }
}
"
    }
  },
  "settings": {
    "optimizer": {
      "enabled": false,
      "runs": 200
    },
    "outputSelection": {
      "*": {
        "*": [
          "evm.bytecode",
          "evm.deployedBytecode",
          "devdoc",
          "userdoc",
          "metadata",
          "abi"
        ]
      }
    },
    "remappings": []
  }
}}