ArtvybeMarketplace

{{
  "language": "Solidity",
  "sources": {
    "@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/interfaces/IERC1363.sol": {
      "content": "// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.4.0) (interfaces/IERC1363.sol)

pragma solidity >=0.6.2;

import {IERC20} from "./IERC20.sol";
import {IERC165} from "./IERC165.sol";

/**
 * @title IERC1363
 * @dev Interface of the ERC-1363 standard as defined in the https://eips.ethereum.org/EIPS/eip-1363[ERC-1363].
 *
 * Defines an extension interface for ERC-20 tokens that supports executing code on a recipient contract
 * after `transfer` or `transferFrom`, or code on a spender contract after `approve`, in a single transaction.
 */
interface IERC1363 is IERC20, IERC165 {
    /*
     * Note: the ERC-165 identifier for this interface is 0xb0202a11.
     * 0xb0202a11 ===
     *   bytes4(keccak256('transferAndCall(address,uint256)')) ^
     *   bytes4(keccak256('transferAndCall(address,uint256,bytes)')) ^
     *   bytes4(keccak256('transferFromAndCall(address,address,uint256)')) ^
     *   bytes4(keccak256('transferFromAndCall(address,address,uint256,bytes)')) ^
     *   bytes4(keccak256('approveAndCall(address,uint256)')) ^
     *   bytes4(keccak256('approveAndCall(address,uint256,bytes)'))
     */

    /**
     * @dev Moves a `value` amount of tokens from the caller's account to `to`
     * and then calls {IERC1363Receiver-onTransferReceived} on `to`.
     * @param to The address which you want to transfer to.
     * @param value The amount of tokens to be transferred.
     * @return A boolean value indicating whether the operation succeeded unless throwing.
     */
    function transferAndCall(address to, uint256 value) external returns (bool);

    /**
     * @dev Moves a `value` amount of tokens from the caller's account to `to`
     * and then calls {IERC1363Receiver-onTransferReceived} on `to`.
     * @param to The address which you want to transfer to.
     * @param value The amount of tokens to be transferred.
     * @param data Additional data with no specified format, sent in call to `to`.
     * @return A boolean value indicating whether the operation succeeded unless throwing.
     */
    function transferAndCall(address to, uint256 value, bytes calldata data) external returns (bool);

    /**
     * @dev Moves a `value` amount of tokens from `from` to `to` using the allowance mechanism
     * and then calls {IERC1363Receiver-onTransferReceived} on `to`.
     * @param from The address which you want to send tokens from.
     * @param to The address which you want to transfer to.
     * @param value The amount of tokens to be transferred.
     * @return A boolean value indicating whether the operation succeeded unless throwing.
     */
    function transferFromAndCall(address from, address to, uint256 value) external returns (bool);

    /**
     * @dev Moves a `value` amount of tokens from `from` to `to` using the allowance mechanism
     * and then calls {IERC1363Receiver-onTransferReceived} on `to`.
     * @param from The address which you want to send tokens from.
     * @param to The address which you want to transfer to.
     * @param value The amount of tokens to be transferred.
     * @param data Additional data with no specified format, sent in call to `to`.
     * @return A boolean value indicating whether the operation succeeded unless throwing.
     */
    function transferFromAndCall(address from, address to, uint256 value, bytes calldata data) external returns (bool);

    /**
     * @dev Sets a `value` amount of tokens as the allowance of `spender` over the
     * caller's tokens and then calls {IERC1363Spender-onApprovalReceived} on `spender`.
     * @param spender The address which will spend the funds.
     * @param value The amount of tokens to be spent.
     * @return A boolean value indicating whether the operation succeeded unless throwing.
     */
    function approveAndCall(address spender, uint256 value) external returns (bool);

    /**
     * @dev Sets a `value` amount of tokens as the allowance of `spender` over the
     * caller's tokens and then calls {IERC1363Spender-onApprovalReceived} on `spender`.
     * @param spender The address which will spend the funds.
     * @param value The amount of tokens to be spent.
     * @param data Additional data with no specified format, sent in call to `spender`.
     * @return A boolean value indicating whether the operation succeeded unless throwing.
     */
    function approveAndCall(address spender, uint256 value, bytes calldata data) external returns (bool);
}
"
    },
    "@openzeppelin/contracts/interfaces/IERC165.sol": {
      "content": "// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.4.0) (interfaces/IERC165.sol)

pragma solidity >=0.4.16;

import {IERC165} from "../utils/introspection/IERC165.sol";
"
    },
    "@openzeppelin/contracts/interfaces/IERC20.sol": {
      "content": "// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.4.0) (interfaces/IERC20.sol)

pragma solidity >=0.4.16;

import {IERC20} from "../token/ERC20/IERC20.sol";
"
    },
    "@openzeppelin/contracts/interfaces/IERC2981.sol": {
      "content": "// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.4.0) (interfaces/IERC2981.sol)

pragma solidity >=0.6.2;

import {IERC165} from "../utils/introspection/IERC165.sol";

/**
 * @dev Interface for the NFT Royalty Standard.
 *
 * A standardized way to retrieve royalty payment information for non-fungible tokens (NFTs) to enable universal
 * support for royalty payments across all NFT marketplaces and ecosystem participants.
 */
interface IERC2981 is IERC165 {
    /**
     * @dev Returns how much royalty is owed and to whom, based on a sale price that may be denominated in any unit of
     * exchange. The royalty amount is denominated and should be paid in that same unit of exchange.
     *
     * NOTE: ERC-2981 allows setting the royalty to 100% of the price. In that case all the price would be sent to the
     * royalty receiver and 0 tokens to the seller. Contracts dealing with royalty should consider empty transfers.
     */
    function royaltyInfo(
        uint256 tokenId,
        uint256 salePrice
    ) external view returns (address receiver, uint256 royaltyAmount);
}
"
    },
    "@openzeppelin/contracts/token/common/ERC2981.sol": {
      "content": "// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.4.0) (token/common/ERC2981.sol)

pragma solidity ^0.8.20;

import {IERC2981} from "../../interfaces/IERC2981.sol";
import {IERC165, ERC165} from "../../utils/introspection/ERC165.sol";

/**
 * @dev Implementation of the NFT Royalty Standard, a standardized way to retrieve royalty payment information.
 *
 * Royalty information can be specified globally for all token ids via {_setDefaultRoyalty}, and/or individually for
 * specific token ids via {_setTokenRoyalty}. The latter takes precedence over the first.
 *
 * Royalty is specified as a fraction of sale price. {_feeDenominator} is overridable but defaults to 10000, meaning the
 * fee is specified in basis points by default.
 *
 * IMPORTANT: ERC-2981 only specifies a way to signal royalty information and does not enforce its payment. See
 * https://eips.ethereum.org/EIPS/eip-2981#optional-royalty-payments[Rationale] in the ERC. Marketplaces are expected to
 * voluntarily pay royalties together with sales, but note that this standard is not yet widely supported.
 */
abstract contract ERC2981 is IERC2981, ERC165 {
    struct RoyaltyInfo {
        address receiver;
        uint96 royaltyFraction;
    }

    RoyaltyInfo private _defaultRoyaltyInfo;
    mapping(uint256 tokenId => RoyaltyInfo) private _tokenRoyaltyInfo;

    /**
     * @dev The default royalty set is invalid (eg. (numerator / denominator) >= 1).
     */
    error ERC2981InvalidDefaultRoyalty(uint256 numerator, uint256 denominator);

    /**
     * @dev The default royalty receiver is invalid.
     */
    error ERC2981InvalidDefaultRoyaltyReceiver(address receiver);

    /**
     * @dev The royalty set for a specific `tokenId` is invalid (eg. (numerator / denominator) >= 1).
     */
    error ERC2981InvalidTokenRoyalty(uint256 tokenId, uint256 numerator, uint256 denominator);

    /**
     * @dev The royalty receiver for `tokenId` is invalid.
     */
    error ERC2981InvalidTokenRoyaltyReceiver(uint256 tokenId, address receiver);

    /// @inheritdoc IERC165
    function supportsInterface(bytes4 interfaceId) public view virtual override(IERC165, ERC165) returns (bool) {
        return interfaceId == type(IERC2981).interfaceId || super.supportsInterface(interfaceId);
    }

    /// @inheritdoc IERC2981
    function royaltyInfo(
        uint256 tokenId,
        uint256 salePrice
    ) public view virtual returns (address receiver, uint256 amount) {
        RoyaltyInfo storage _royaltyInfo = _tokenRoyaltyInfo[tokenId];
        address royaltyReceiver = _royaltyInfo.receiver;
        uint96 royaltyFraction = _royaltyInfo.royaltyFraction;

        if (royaltyReceiver == address(0)) {
            royaltyReceiver = _defaultRoyaltyInfo.receiver;
            royaltyFraction = _defaultRoyaltyInfo.royaltyFraction;
        }

        uint256 royaltyAmount = (salePrice * royaltyFraction) / _feeDenominator();

        return (royaltyReceiver, royaltyAmount);
    }

    /**
     * @dev The denominator with which to interpret the fee set in {_setTokenRoyalty} and {_setDefaultRoyalty} as a
     * fraction of the sale price. Defaults to 10000 so fees are expressed in basis points, but may be customized by an
     * override.
     */
    function _feeDenominator() internal pure virtual returns (uint96) {
        return 10000;
    }

    /**
     * @dev Sets the royalty information that all ids in this contract will default to.
     *
     * Requirements:
     *
     * - `receiver` cannot be the zero address.
     * - `feeNumerator` cannot be greater than the fee denominator.
     */
    function _setDefaultRoyalty(address receiver, uint96 feeNumerator) internal virtual {
        uint256 denominator = _feeDenominator();
        if (feeNumerator > denominator) {
            // Royalty fee will exceed the sale price
            revert ERC2981InvalidDefaultRoyalty(feeNumerator, denominator);
        }
        if (receiver == address(0)) {
            revert ERC2981InvalidDefaultRoyaltyReceiver(address(0));
        }

        _defaultRoyaltyInfo = RoyaltyInfo(receiver, feeNumerator);
    }

    /**
     * @dev Removes default royalty information.
     */
    function _deleteDefaultRoyalty() internal virtual {
        delete _defaultRoyaltyInfo;
    }

    /**
     * @dev Sets the royalty information for a specific token id, overriding the global default.
     *
     * Requirements:
     *
     * - `receiver` cannot be the zero address.
     * - `feeNumerator` cannot be greater than the fee denominator.
     */
    function _setTokenRoyalty(uint256 tokenId, address receiver, uint96 feeNumerator) internal virtual {
        uint256 denominator = _feeDenominator();
        if (feeNumerator > denominator) {
            // Royalty fee will exceed the sale price
            revert ERC2981InvalidTokenRoyalty(tokenId, feeNumerator, denominator);
        }
        if (receiver == address(0)) {
            revert ERC2981InvalidTokenRoyaltyReceiver(tokenId, address(0));
        }

        _tokenRoyaltyInfo[tokenId] = RoyaltyInfo(receiver, feeNumerator);
    }

    /**
     * @dev Resets royalty information for the token id back to the global default.
     */
    function _resetTokenRoyalty(uint256 tokenId) internal virtual {
        delete _tokenRoyaltyInfo[tokenId];
    }
}
"
    },
    "@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/token/ERC20/utils/SafeERC20.sol": {
      "content": "// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.3.0) (token/ERC20/utils/SafeERC20.sol)

pragma solidity ^0.8.20;

import {IERC20} from "../IERC20.sol";
import {IERC1363} from "../../../interfaces/IERC1363.sol";

/**
 * @title SafeERC20
 * @dev Wrappers around ERC-20 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 {
    /**
     * @dev An operation with an ERC-20 token failed.
     */
    error SafeERC20FailedOperation(address token);

    /**
     * @dev Indicates a failed `decreaseAllowance` request.
     */
    error SafeERC20FailedDecreaseAllowance(address spender, uint256 currentAllowance, uint256 requestedDecrease);

    /**
     * @dev Transfer `value` amount of `token` from the calling contract to `to`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     */
    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeCall(token.transfer, (to, value)));
    }

    /**
     * @dev Transfer `value` amount of `token` from `from` to `to`, spending the approval given by `from` to the
     * calling contract. If `token` returns no value, non-reverting calls are assumed to be successful.
     */
    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeCall(token.transferFrom, (from, to, value)));
    }

    /**
     * @dev Variant of {safeTransfer} that returns a bool instead of reverting if the operation is not successful.
     */
    function trySafeTransfer(IERC20 token, address to, uint256 value) internal returns (bool) {
        return _callOptionalReturnBool(token, abi.encodeCall(token.transfer, (to, value)));
    }

    /**
     * @dev Variant of {safeTransferFrom} that returns a bool instead of reverting if the operation is not successful.
     */
    function trySafeTransferFrom(IERC20 token, address from, address to, uint256 value) internal returns (bool) {
        return _callOptionalReturnBool(token, abi.encodeCall(token.transferFrom, (from, to, value)));
    }

    /**
     * @dev Increase the calling contract's allowance toward `spender` by `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful.
     *
     * IMPORTANT: If the token implements ERC-7674 (ERC-20 with temporary allowance), and if the "client"
     * smart contract uses ERC-7674 to set temporary allowances, then the "client" smart contract should avoid using
     * this function. Performing a {safeIncreaseAllowance} or {safeDecreaseAllowance} operation on a token contract
     * that has a non-zero temporary allowance (for that particular owner-spender) will result in unexpected behavior.
     */
    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 oldAllowance = token.allowance(address(this), spender);
        forceApprove(token, spender, oldAllowance + value);
    }

    /**
     * @dev Decrease the calling contract's allowance toward `spender` by `requestedDecrease`. If `token` returns no
     * value, non-reverting calls are assumed to be successful.
     *
     * IMPORTANT: If the token implements ERC-7674 (ERC-20 with temporary allowance), and if the "client"
     * smart contract uses ERC-7674 to set temporary allowances, then the "client" smart contract should avoid using
     * this function. Performing a {safeIncreaseAllowance} or {safeDecreaseAllowance} operation on a token contract
     * that has a non-zero temporary allowance (for that particular owner-spender) will result in unexpected behavior.
     */
    function safeDecreaseAllowance(IERC20 token, address spender, uint256 requestedDecrease) internal {
        unchecked {
            uint256 currentAllowance = token.allowance(address(this), spender);
            if (currentAllowance < requestedDecrease) {
                revert SafeERC20FailedDecreaseAllowance(spender, currentAllowance, requestedDecrease);
            }
            forceApprove(token, spender, currentAllowance - requestedDecrease);
        }
    }

    /**
     * @dev Set the calling contract's allowance toward `spender` to `value`. If `token` returns no value,
     * non-reverting calls are assumed to be successful. Meant to be used with tokens that require the approval
     * to be set to zero before setting it to a non-zero value, such as USDT.
     *
     * NOTE: If the token implements ERC-7674, this function will not modify any temporary allowance. This function
     * only sets the "standard" allowance. Any temporary allowance will remain active, in addition to the value being
     * set here.
     */
    function forceApprove(IERC20 token, address spender, uint256 value) internal {
        bytes memory approvalCall = abi.encodeCall(token.approve, (spender, value));

        if (!_callOptionalReturnBool(token, approvalCall)) {
            _callOptionalReturn(token, abi.encodeCall(token.approve, (spender, 0)));
            _callOptionalReturn(token, approvalCall);
        }
    }

    /**
     * @dev Performs an {ERC1363} transferAndCall, with a fallback to the simple {ERC20} transfer if the target has no
     * code. This can be used to implement an {ERC721}-like safe transfer that rely on {ERC1363} checks when
     * targeting contracts.
     *
     * Reverts if the returned value is other than `true`.
     */
    function transferAndCallRelaxed(IERC1363 token, address to, uint256 value, bytes memory data) internal {
        if (to.code.length == 0) {
            safeTransfer(token, to, value);
        } else if (!token.transferAndCall(to, value, data)) {
            revert SafeERC20FailedOperation(address(token));
        }
    }

    /**
     * @dev Performs an {ERC1363} transferFromAndCall, with a fallback to the simple {ERC20} transferFrom if the target
     * has no code. This can be used to implement an {ERC721}-like safe transfer that rely on {ERC1363} checks when
     * targeting contracts.
     *
     * Reverts if the returned value is other than `true`.
     */
    function transferFromAndCallRelaxed(
        IERC1363 token,
        address from,
        address to,
        uint256 value,
        bytes memory data
    ) internal {
        if (to.code.length == 0) {
            safeTransferFrom(token, from, to, value);
        } else if (!token.transferFromAndCall(from, to, value, data)) {
            revert SafeERC20FailedOperation(address(token));
        }
    }

    /**
     * @dev Performs an {ERC1363} approveAndCall, with a fallback to the simple {ERC20} approve if the target has no
     * code. This can be used to implement an {ERC721}-like safe transfer that rely on {ERC1363} checks when
     * targeting contracts.
     *
     * NOTE: When the recipient address (`to`) has no code (i.e. is an EOA), this function behaves as {forceApprove}.
     * Opposedly, when the recipient address (`to`) has code, this function only attempts to call {ERC1363-approveAndCall}
     * once without retrying, and relies on the returned value to be true.
     *
     * Reverts if the returned value is other than `true`.
     */
    function approveAndCallRelaxed(IERC1363 token, address to, uint256 value, bytes memory data) internal {
        if (to.code.length == 0) {
            forceApprove(token, to, value);
        } else if (!token.approveAndCall(to, value, data)) {
            revert SafeERC20FailedOperation(address(token));
        }
    }

    /**
     * @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).
     *
     * This is a variant of {_callOptionalReturnBool} that reverts if call fails to meet the requirements.
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        uint256 returnSize;
        uint256 returnValue;
        assembly ("memory-safe") {
            let success := call(gas(), token, 0, add(data, 0x20), mload(data), 0, 0x20)
            // bubble errors
            if iszero(success) {
                let ptr := mload(0x40)
                returndatacopy(ptr, 0, returndatasize())
                revert(ptr, returndatasize())
            }
            returnSize := returndatasize()
            returnValue := mload(0)
        }

        if (returnSize == 0 ? address(token).code.length == 0 : returnValue != 1) {
            revert SafeERC20FailedOperation(address(token));
        }
    }

    /**
     * @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).
     *
     * This is a variant of {_callOptionalReturn} that silently catches all reverts and returns a bool instead.
     */
    function _callOptionalReturnBool(IERC20 token, bytes memory data) private returns (bool) {
        bool success;
        uint256 returnSize;
        uint256 returnValue;
        assembly ("memory-safe") {
            success := call(gas(), token, 0, add(data, 0x20), mload(data), 0, 0x20)
            returnSize := returndatasize()
            returnValue := mload(0)
        }
        return success && (returnSize == 0 ? address(token).code.length > 0 : returnValue == 1);
    }
}
"
    },
    "@openzeppelin/contracts/token/ERC721/IERC721.sol": {
      "content": "// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.4.0) (token/ERC721/IERC721.sol)

pragma solidity >=0.6.2;

import {IERC165} from "../../utils/introspection/IERC165.sol";

/**
 * @dev Required interface of an ERC-721 compliant contract.
 */
interface IERC721 is IERC165 {
    /**
     * @dev Emitted when `tokenId` token is transferred from `from` to `to`.
     */
    event Transfer(address indexed from, address indexed to, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables `approved` to manage the `tokenId` token.
     */
    event Approval(address indexed owner, address indexed approved, uint256 indexed tokenId);

    /**
     * @dev Emitted when `owner` enables or disables (`approved`) `operator` to manage all of its assets.
     */
    event ApprovalForAll(address indexed owner, address indexed operator, bool approved);

    /**
     * @dev Returns the number of tokens in ``owner``'s account.
     */
    function balanceOf(address owner) external view returns (uint256 balance);

    /**
     * @dev Returns the owner of the `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function ownerOf(uint256 tokenId) external view returns (address owner);

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon
     *   a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(address from, address to, uint256 tokenId, bytes calldata data) external;

    /**
     * @dev Safely transfers `tokenId` token from `from` to `to`, checking first that contract recipients
     * are aware of the ERC-721 protocol to prevent tokens from being forever locked.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must exist and be owned by `from`.
     * - If the caller is not `from`, it must have been allowed to move this token by either {approve} or
     *   {setApprovalForAll}.
     * - If `to` refers to a smart contract, it must implement {IERC721Receiver-onERC721Received}, which is called upon
     *   a safe transfer.
     *
     * Emits a {Transfer} event.
     */
    function safeTransferFrom(address from, address to, uint256 tokenId) external;

    /**
     * @dev Transfers `tokenId` token from `from` to `to`.
     *
     * WARNING: Note that the caller is responsible to confirm that the recipient is capable of receiving ERC-721
     * or else they may be permanently lost. Usage of {safeTransferFrom} prevents loss, though the caller must
     * understand this adds an external call which potentially creates a reentrancy vulnerability.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `tokenId` token must be owned by `from`.
     * - If the caller is not `from`, it must be approved to move this token by either {approve} or {setApprovalForAll}.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address from, address to, uint256 tokenId) external;

    /**
     * @dev Gives permission to `to` to transfer `tokenId` token to another account.
     * The approval is cleared when the token is transferred.
     *
     * Only a single account can be approved at a time, so approving the zero address clears previous approvals.
     *
     * Requirements:
     *
     * - The caller must own the token or be an approved operator.
     * - `tokenId` must exist.
     *
     * Emits an {Approval} event.
     */
    function approve(address to, uint256 tokenId) external;

    /**
     * @dev Approve or remove `operator` as an operator for the caller.
     * Operators can call {transferFrom} or {safeTransferFrom} for any token owned by the caller.
     *
     * Requirements:
     *
     * - The `operator` cannot be the address zero.
     *
     * Emits an {ApprovalForAll} event.
     */
    function setApprovalForAll(address operator, bool approved) external;

    /**
     * @dev Returns the account approved for `tokenId` token.
     *
     * Requirements:
     *
     * - `tokenId` must exist.
     */
    function getApproved(uint256 tokenId) external view returns (address operator);

    /**
     * @dev Returns if the `operator` is allowed to manage all of the assets of `owner`.
     *
     * See {setApprovalForAll}
     */
    function isApprovedForAll(address owner, address operator) external view returns (bool);
}
"
    },
    "@openzeppelin/contracts/token/ERC721/IERC721Receiver.sol": {
      "content": "// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.4.0) (token/ERC721/IERC721Receiver.sol)

pragma solidity >=0.5.0;

/**
 * @title ERC-721 token receiver interface
 * @dev Interface for any contract that wants to support safeTransfers
 * from ERC-721 asset contracts.
 */
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 `IERC721Receiver.onERC721Received.selector`.
     */
    function onERC721Received(
        address operator,
        address from,
        uint256 tokenId,
        bytes calldata data
    ) external returns (bytes4);
}
"
    },
    "@openzeppelin/contracts/token/ERC721/utils/ERC721Holder.sol": {
      "content": "// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.0.0) (token/ERC721/utils/ERC721Holder.sol)

pragma solidity ^0.8.20;

import {IERC721Receiver} from "../IERC721Receiver.sol";

/**
 * @dev Implementation of the {IERC721Receiver} interface.
 *
 * Accepts all token transfers.
 * Make sure the contract is able to use its token with {IERC721-safeTransferFrom}, {IERC721-approve} or
 * {IERC721-setApprovalForAll}.
 */
abstract contract ERC721Holder is IERC721Receiver {
    /**
     * @dev See {IERC721Receiver-onERC721Received}.
     *
     * Always returns `IERC721Receiver.onERC721Received.selector`.
     */
    function onERC721Received(address, address, uint256, bytes memory) public virtual returns (bytes4) {
        return this.onERC721Received.selector;
    }
}
"
    },
    "@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;
    }
}
"
    },
    "@openzeppelin/contracts/utils/introspection/ERC165.sol": {
      "content": "// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.4.0) (utils/introspection/ERC165.sol)

pragma solidity ^0.8.20;

import {IERC165} from "./IERC165.sol";

/**
 * @dev Implementation of the {IERC165} interface.
 *
 * Contracts that want to implement ERC-165 should inherit from this contract and override {supportsInterface} to check
 * for the additional interface id that will be supported. For example:
 *
 * ```solidity
 * function supportsInterface(bytes4 interfaceId) public view virtual override returns (bool) {
 *     return interfaceId == type(MyInterface).interfaceId || super.supportsInterface(interfaceId);
 * }
 * ```
 */
abstract contract ERC165 is IERC165 {
    /// @inheritdoc IERC165
    function supportsInterface(bytes4 interfaceId) public view virtual returns (bool) {
        return interfaceId == type(IERC165).interfaceId;
    }
}
"
    },
    "@openzeppelin/contracts/utils/introspection/IERC165.sol": {
      "content": "// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.4.0) (utils/introspection/IERC165.sol)

pragma solidity >=0.4.16;

/**
 * @dev Interface of the ERC-165 standard, as defined in the
 * https://eips.ethereum.org/EIPS/eip-165[ERC].
 *
 * 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[ERC 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);
}
"
    },
    "@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;
    }
}
"
    },
    "contracts/ArtvybeMarketplace.sol": {
      "content": "// SPDX-License-Identifier: MIT
pragma solidity 0.8.20;

import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/utils/Pausable.sol";
import "@openzeppelin/contracts/utils/ReentrancyGuard.sol";
import "@openzeppelin/contracts/token/ERC721/IERC721.sol";
import "@openzeppelin/contracts/token/ERC721/utils/ERC721Holder.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
import "@openzeppelin/contracts/token/ERC20/utils/SafeERC20.sol";
import "@openzeppelin/contracts/token/common/ERC2981.sol";
import "./interfaces/IArtvybeMarketplace.sol";

contract ArtvybeMarketplace is 
    Ownable, 
    Pausable, 
    ReentrancyGuard, 
    ERC721Holder,
    IArtvybeMarketplace 
{
    using SafeERC20 for IERC20;

    // Platform configuration
    uint96 public platformFeeBps; 
    address public platformTreasury;
    address public admin;
    
    // Auction configuration
    uint256 public constant MIN_AUCTION_DURATION = 1 hours;
    uint256 public constant MIN_BID_INCREMENT = 0.01 ether;
    
    // Offer configuration
    uint256 public constant MIN_OFFER_DURATION = 1 hours;
    uint256 public constant MAX_OFFER_DURATION = 30 days;
    
    // Storage
    mapping(address => mapping(uint256 => Listing)) public listings;
    mapping(address => mapping(uint256 => mapping(address => Offer))) public offers; // nftContract => tokenId => offerer => Offer
    mapping(address => mapping(uint256 => address[])) public offerers; // nftContract => tokenId => offerer addresses
    
    // Errors
    error ListingNotFound();
    error ListingNotActive();
    error NotListingOwner();
    error InvalidPrice();
    error InvalidDuration();
    error InsufficientBid();
    error AuctionNotEnded();
    error AuctionAlreadyFinalized();
    error TransferFailed();
    error InvalidParameters();
    error InvalidPaymentCurrency();
    error InsufficientAllowance();
    error OfferNotFound();
    error OfferNotActive();
    error NotOfferOwner();
    error OfferExpired();
    error NotNFTOwner();
    error OfferAlreadyExists();
    error NotAdmin();

    // Modifiers
    modifier onlyAdmin() {
        if (msg.sender != admin && msg.sender != owner()) revert NotAdmin();
        _;
    }

    /**
     * @dev Add or update a bidder in the top 5 list
     * @param listing The listing to update
     * @param bidder The bidder address
     * @param bidAmount The bid amount
     * @return success True if bidder was added/updated, false if bid was too low
     * @return refundBidder Address of bidder to refund (if any)
     * @return refundAmount Amount to refund (if any)
     */
    function _addOrUpdateBidder(Listing storage listing, address bidder, uint256 bidAmount) internal returns (bool success, address refundBidder, uint256 refundAmount) {
        // Check if bidder already exists in the list
        int256 existingIndex = _findBidderIndex(listing, bidder);
        
        if (existingIndex >= 0) {
            // Update existing bidder's amount
            listing.topBidders[uint256(existingIndex)].bidAmount = bidAmount;
            success = true;
        } else {
            // Add new bidder
            if (listing.bidderCount < 5) {
                // Add to end if less than 5 bidders
                listing.topBidders[listing.bidderCount] = Bidder(bidder, bidAmount);
                listing.bidderCount++;
                success = true;
            } else {
                // Replace the lowest bidder if new bid is higher
                if (bidAmount > listing.topBidders[4].bidAmount) {
                    // Store info of the bidder being replaced for refund
                    refundBidder = listing.topBidders[4].bidder;
                    refundAmount = listing.topBidders[4].bidAmount;
                    
                    // Replace the lowest bidder
                    listing.topBidders[4] = Bidder(bidder, bidAmount);
                    success = true;
                } else {
                    success = false; // Bid too low, don't add
                }
            }
        }
        
        if (success) {
            // Sort the bidders by bid amount (highest first)
            _sortBidders(listing);
        }
    }

    /**
     * @dev Remove a bidder from the top 5 list
     * @param listing The listing to update
     * @param bidder The bidder address to remove
     */
    function _removeBidder(Listing storage listing, address bidder) internal {
        int256 index = _findBidderIndex(listing, bidder);
        if (index < 0) return; // Bidder not found
        
        uint256 bidderIndex = uint256(index);
        
        // Shift all bidders after the removed one to the left
        for (uint256 i = bidderIndex; i < listing.bidderCount - 1; i++) {
            listing.topBidders[i] = listing.topBidders[i + 1];
        }
        
        // Clear the last position and decrease count
        listing.topBidders[listing.bidderCount - 1] = Bidder(address(0), 0);
        listing.bidderCount--;
    }

    /**
     * @dev Find the index of a bidder in the top 5 list
     * @param listing The listing to search
     * @param bidder The bidder address to find
     * @return The index of the bidder, or -1 if not found
     */
    function _findBidderIndex(Listing storage listing, address bidder) internal view returns (int256) {
        for (uint256 i = 0; i < listing.bidderCount; i++) {
            if (listing.topBidders[i].bidder == bidder) {
                return int256(i);
            }
        }
        return -1;
    }

    /**
     * @dev Sort bidders by bid amount (highest first)
     * @param listing The listing to sort
     */
    function _sortBidders(Listing storage listing) internal {
        // Simple bubble sort for small array (5 elements max)
        for (uint256 i = 0; i < listing.bidderCount - 1; i++) {
            for (uint256 j = 0; j < listing.bidderCount - i - 1; j++) {
                if (listing.topBidders[j].bidAmount < listing.topBidders[j + 1].bidAmount) {
                    Bidder memory temp = listing.topBidders[j];
                    listing.topBidders[j] = listing.topBidders[j + 1];
                    listing.topBidders[j + 1] = temp;
                }
            }
        }
    }

    /**
     * @dev Get the highest bid amount from the top 5 list
     * @param listing The listing to check
     * @return The highest bid amount, or 0 if no bidders
     */
    function _getHighestBid(Listing storage listing) internal view returns (uint256) {
        if (listing.bidderCount == 0) return 0;
        return listing.topBidders[0].bidAmount;
    }

    /**
     * @dev Get the highest bidder from the top 5 list
     * @param listing The listing to check
     * @return The highest bidder address, or address(0) if no bidders
     */
    function _getHighestBidder(Listing storage listing) internal view returns (address) {
        if (listing.bidderCount == 0) return address(0);
        return listing.topBidders[0].bidder;
    }

    /**
     * @dev Refund all bidders in the top 5 list
     * @param listing The listing to refund bidders for
     */
    function _refundAllBidders(Listing storage listing) internal {
        for (uint256 i = 0; i < listing.bidderCount; i++) {
            Bidder memory bidder = listing.topBidders[i];
            if (bidder.bidder != address(0) && bidder.bidAmount > 0) {
                if (listing.paymentCurrency == address(0)) {
                    // Native token refund
                    (bool success, ) = bidder.bidder.call{value: bidder.bidAmount}("");
                    if (!success) revert TransferFailed();
                } else {
                    // ERC20 token refund
                    IERC20 paymentToken = IERC20(listing.paymentCurrency);
                    paymentToken.safeTransfer(bidder.bidder, bidder.bidAmount);
                }
            }
        }
        
        // Clear all bidders
        for (uint256 i = 0; i < listing.bidderCount; i++) {
            listing.topBidders[i] = Bidder(address(0), 0);
        }
        listing.bidderCount = 0;
    }

    constructor(address _platformTreasury, address _owner) Ownable(_owner) {
        if (_platformTreasury == address(0)) revert InvalidParameters();
        if (_owner == address(0)) revert InvalidParameters();
        platformTreasury = _platformTreasury;
        platformFeeBps = 200; // Default 2%
        admin = _owner; // Owner starts as admin
    }

    /**
     * @dev List an NFT for fixed price sale
     */
    function listFixedPrice(
        address nftContract,
        uint256 tokenId,
        uint256 price,
        address paymentCurrency
    ) external whenNotPaused nonReentrant {
        if (price == 0) revert InvalidPrice();
        
        // Transfer NFT to marketplace (escrow)
        IERC721(nftContract).safeTransferFrom(msg.sender, address(this), tokenId);
        
        // Create listing
        listings[nftContract][tokenId] = Listing({
            seller: msg.sender,
            nftContract: nftContract,
            tokenId: tokenId,
            listingType: ListingType.FixedPrice,
            price: price,
            paymentCurrency: paymentCurrency,
            startTime: block.timestamp,
            endTime: 0, // Not used for fixed price
            topBidders: [Bidder(address(0), 0), Bidder(address(0), 0), Bidder(address(0), 0), Bidder(address(0), 0), Bidder(address(0), 0)],
            bidderCount: 0,
            active: true
        });
        
        emit FixedPriceListed(msg.sender, nftContract, tokenId, price, paymentCurrency);
    }

    /**
     * @dev List an NFT for auction
     */
    function listAuction(
        address nftContract,
        uint256 tokenId,
        uint256 reservePrice,
        address paymentCurrency,
        uint256 duration
    ) external whenNotPaused nonReentrant {
        if (reservePrice == 0) revert InvalidPrice();
        if (duration < MIN_AUCTION_DURATION) revert InvalidDuration();
        
        // Transfer NFT to marketplace (escrow)
        IERC721(nftContract).safeTransferFrom(msg.sender, address(this), tokenId);
        
        // Create listing
        listings[nftContract][tokenId] = Listing({
            seller: msg.sender,
            nftContract: nftContract,
            tokenId: tokenId,
            listingType: ListingType.EnglishAuction,
            price: reservePrice,
            paymentCurrency: paymentCurrency,
            startTime: block.timestamp,
            endTime: block.timestamp + duration,
            topBidders: [Bidder(address(0), 0), Bidder(address(0), 0), Bidder(address(0), 0), Bidder(address(0), 0), Bidder(address(0), 0)],
            bidderCount: 0,
            active: true
        });
        
        emit AuctionListed(msg.sender, nftContract, tokenId, reservePrice, paymentCurrency, block.timestamp + duration);
    }

    /**
     * @dev Buy a fixed price listing
     */
    function buyFixed(address nftContract, uint256 tokenId) external payable whenNotPaused nonReentrant {
        Listing storage listing = listings[nftContract][tokenId];
        
        if (!listing.active) revert ListingNotActive();
        if (listing.listingType != ListingType.FixedPrice) revert ListingNotFound();
        
        if (listing.paymentCurrency == address(0)) {
            // Native token payment
            if (msg.value != listing.price) revert InvalidPrice();
        } else {
            // ERC20 token payment
            if (msg.value > 0) revert InvalidPrice(); // Should not send ETH for ERC20 payments
            
            IERC20 paymentToken = IERC20(listing.paymentCurrency);
            if (paymentToken.allowance(msg.sender, address(this)) < listing.price) {
                revert InsufficientAllowance();
            }
            
            // Transfer ERC20 tokens from buyer to marketplace
            paymentToken.safeTransferFrom(msg.sender, address(this), listing.price);
        }
        
        // Mark listing as inactive
        listing.active = false;
        
        // Distribute proceeds
        _distributeProceeds(nftContract, tokenId, listing.price, listing.seller, listing.paymentCurrency);
        
        // Transfer NFT to buyer
        IERC721(nftContract).safeTransferFrom(address(this), msg.sender, tokenId);
        
        emit ItemBought(msg.sender, nftContract, tokenId, listing.price, listing.paymentCurrency);
    }

    /**
     * @dev Place a bid on an auction
     * @param nftContract Address of the NFT contract
     * @param tokenId Token ID to bid on
     * @param bidAmount Amount to bid (only used for ERC20 tokens, ignored for native tokens)
     */
    function placeBid(address nftContract, uint256 tokenId, uint256 bidAmount) external payable whenNotPaused nonReentrant {
        Listing storage listing = listings[nftContract][tokenId];
        
        if (!listing.active) revert ListingNotActive();
        if (listing.listingType != ListingType.EnglishAuction) revert ListingNotFound();
        if (block.timestamp >= listing.endTime) revert AuctionNotEnded();
        
        uint256 highestBid = _getHighestBid(listing);
        uint256 minBid = highestBid == 0 ? listing.price : highestBid + MIN_BID_INCREMENT;
        uint256 actualBid;
        
        if (listing.paymentCurrency == address(0)) {
            // Native token payment
            if (msg.value < minBid) revert InsufficientBid();
            actualBid = msg.value;
        } else {
            // ERC20 token payment
            if (msg.value > 0) revert InvalidPrice(); // Should not send ETH for ERC20 payments
            if (bidAmount < minBid) revert InsufficientBid();
            actualBid = bidAmount;
        }
        
        // Check if bidder already exists and get their previous bid
        int256 existingIndex = _findBidderIndex(listing, msg.sender);
        uint256 previousBid = 0;
        if (existingIndex >= 0) {
            previousBid = listing.topBidders[uint256(existingIndex)].bidAmount;
        }
        
        // Calculate net payment needed
        uint256 netPayment = actualBid - previousBid;
        
        if (listing.paymentCurrency == address(0)) {
            // For native tokens, refund the excess if they sent more than needed
            if (msg.value > netPayment) {
                uint256 excess = msg.value - netPayment;
                (bool success, ) = msg.sender.call{value: excess}("");
                if (!success) revert TransferFailed();
            } else if (msg.value < netPayment) {
                revert InsufficientBid();
            }
        } else {
            // ERC20 token payment
            IERC20 paymentToken = IERC20(listing.paymentCurrency);
            
            // Check allowance for the net payment (not the full bidAmount)
            if (paymentToken.allowance(msg.sender, address(this)) < netPayment) {
                revert InsufficientAllowance();
            }
            
            // Transfer only the net payment (difference) for ERC20 tokens
            paymentToken.safeTransferFrom(msg.sender, address(this), netPayment);
        }
        
        // Add or update bidder in top 5 list
        (bool bidderAdded, address refundBidder, uint256 refundAmount) = _addOrUpdateBidder(listing, msg.sender, actualBid);
        
        if (!bidderAdded) {
            // Bid was too low, refund the bidder
            if (listing.paymentCurrency == address(0)) {
                // Native token refund
                (bool success, ) = msg.sender.call{value: actualBid}("");
                if (!success) revert TransferFailed();
            } else {
                // ERC20 token refund
                IERC20 paymentToken = IERC20(listing.paymentCurrency);
                paymentToken.safeTransfer(msg.sender, actualBid);
            }
            revert InsufficientBid(); // Revert with appropriate error
        }
        
        // Refund the bidder who got pushed out of top 5 (if any)
        if (refundBidder != address(0) && refundAmount > 0) {
            if (listing.paymentCurrency == address(0)) {
                // Native token refund
                (bool success, ) = refundBidder.call{value: refundAmount}("");
                if (!success) revert TransferFailed();
            } else {
                // ERC20 token refund
                IERC20 paymentToken = IERC20(listing.paymentCurrency);
                paymentToken.safeTransfer(refundBidder, refundAmount);
            }
        }
        
        emit BidPlaced(msg.sender, nftContract, tokenId, actualBid, listing.paymentCurrency);
    }

    /**
     * @dev Finalize an auction
     */
    function finalizeAuction(address nftContract, uint256 tokenId) external whenNotPaused nonReentrant {
        Listing storage listing = listings[nftContract][tokenId];
        
        if (!listing.active) revert ListingNotActive();
        if (listing.listingType != ListingType.EnglishAuction) revert ListingNotFound();
        if (block.timestamp < listing.endTime) revert AuctionNotEnded();
        
        // Mark listing as inactive
        listing.active = false;
        
        if (listing.bidderCount == 0) {
            // No bids, return NFT to seller
            IERC721(nftContract).safeTransferFrom(address(this), listing.seller, tokenId);
            emit AuctionFinalized(address(0), nftContract, tokenId, 0, listing.paymentCurrency);
        } else {
            // Get winner (highest bidder)
            address winner = _getHighestBidder(listing);
            uint256 winningBid = _getHighestBid(listing);
            
            // Distribute proceeds to seller
            _distributeProceeds(nftContract, tokenId, winningBid, listing.seller, listing.paymentCurrency);
            
            // Transfer NFT to winner
            IERC721(nftContract).safeTransferFrom(address(this), winner, tokenId);
            
            // Refund bidders 2-5 (if they exist)
            for (uint256 i = 1; i < listing.bidderCount; i++) {
                Bidder memory bidder = listing.topBidders[i];
                if (bidder.bidder != address(0) && bidder.bidAmount > 0) {
                    if (listing.paymentCurrency == address(0)) {
                        // Native token refund
                        (bool success, ) = bidder.bidder.call{value: bidder.bidAmount}("");
                        if (!success) revert TransferFailed();
                    } else {
                        // ERC20 token refund
                        IERC20 paymentToken = IERC20(listing.paymentCurrency);
                        paymentToken.safeTransfer(bidder.bidder, bidder.bidAmount);
                    }
                }
            }
            
            // Clear all bidders
            for (uint256 i = 0; i < listing.bidderCount; i++) {
                listing.topBidders[i] = Bidder(address(0), 0);
            }
            listing.bidderCount = 0;
            
            emit AuctionFinalized(winner, nftContract, tokenId, winningBid, listing.paymentCurrency);
        }
    }

    /**
     * @dev Cancel a bid (only bidder, only if auction hasn't ended)
     */
    function cancelBid(address nftContract, uint256 tokenId) external whenNotPaused nonReentrant {
        Listing storage listing = listings[nftContract][tokenId];
        
        if (!listing.active) revert ListingNotActive();
        if (listing.listingType != ListingType.EnglishAuction) revert ListingNotFound();
        if (block.timestamp >= listing.endTime) revert AuctionNotEnded(); // Can't cancel after auction ends