Cryo Explorer Ethereum Mainnet

// 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);
    }
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.4.0) (interfaces/draft-IERC6093.sol)
pragma solidity >=0.8.4;

/**
 * @dev Standard ERC-20 Errors
 * Interface of the https://eips.ethereum.org/EIPS/eip-6093[ERC-6093] custom errors for ERC-20 tokens.
 */
interface IERC20Errors {
    /**
     * @dev Indicates an error related to the current `balance` of a `sender`. Used in transfers.
     * @param sender Address whose tokens are being transferred.
     * @param balance Current balance for the interacting account.
     * @param needed Minimum amount required to perform a transfer.
     */
    error ERC20InsufficientBalance(address sender, uint256 balance, uint256 needed);

    /**
     * @dev Indicates a failure with the token `sender`. Used in transfers.
     * @param sender Address whose tokens are being transferred.
     */
    error ERC20InvalidSender(address sender);

    /**
     * @dev Indicates a failure with the token `receiver`. Used in transfers.
     * @param receiver Address to which tokens are being transferred.
     */
    error ERC20InvalidReceiver(address receiver);

    /**
     * @dev Indicates a failure with the `spender`’s `allowance`. Used in transfers.
     * @param spender Address that may be allowed to operate on tokens without being their owner.
     * @param allowance Amount of tokens a `spender` is allowed to operate with.
     * @param needed Minimum amount required to perform a transfer.
     */
    error ERC20InsufficientAllowance(address spender, uint256 allowance, uint256 needed);

    /**
     * @dev Indicates a failure with the `approver` of a token to be approved. Used in approvals.
     * @param approver Address initiating an approval operation.
     */
    error ERC20InvalidApprover(address approver);

    /**
     * @dev Indicates a failure with the `spender` to be approved. Used in approvals.
     * @param spender Address that may be allowed to operate on tokens without being their owner.
     */
    error ERC20InvalidSpender(address spender);
}

/**
 * @dev Standard ERC-721 Errors
 * Interface of the https://eips.ethereum.org/EIPS/eip-6093[ERC-6093] custom errors for ERC-721 tokens.
 */
interface IERC721Errors {
    /**
     * @dev Indicates that an address can't be an owner. For example, `address(0)` is a forbidden owner in ERC-20.
     * Used in balance queries.
     * @param owner Address of the current owner of a token.
     */
    error ERC721InvalidOwner(address owner);

    /**
     * @dev Indicates a `tokenId` whose `owner` is the zero address.
     * @param tokenId Identifier number of a token.
     */
    error ERC721NonexistentToken(uint256 tokenId);

    /**
     * @dev Indicates an error related to the ownership over a particular token. Used in transfers.
     * @param sender Address whose tokens are being transferred.
     * @param tokenId Identifier number of a token.
     * @param owner Address of the current owner of a token.
     */
    error ERC721IncorrectOwner(address sender, uint256 tokenId, address owner);

    /**
     * @dev Indicates a failure with the token `sender`. Used in transfers.
     * @param sender Address whose tokens are being transferred.
     */
    error ERC721InvalidSender(address sender);

    /**
     * @dev Indicates a failure with the token `receiver`. Used in transfers.
     * @param receiver Address to which tokens are being transferred.
     */
    error ERC721InvalidReceiver(address receiver);

    /**
     * @dev Indicates a failure with the `operator`’s approval. Used in transfers.
     * @param operator Address that may be allowed to operate on tokens without being their owner.
     * @param tokenId Identifier number of a token.
     */
    error ERC721InsufficientApproval(address operator, uint256 tokenId);

    /**
     * @dev Indicates a failure with the `approver` of a token to be approved. Used in approvals.
     * @param approver Address initiating an approval operation.
     */
    error ERC721InvalidApprover(address approver);

    /**
     * @dev Indicates a failure with the `operator` to be approved. Used in approvals.
     * @param operator Address that may be allowed to operate on tokens without being their owner.
     */
    error ERC721InvalidOperator(address operator);
}

/**
 * @dev Standard ERC-1155 Errors
 * Interface of the https://eips.ethereum.org/EIPS/eip-6093[ERC-6093] custom errors for ERC-1155 tokens.
 */
interface IERC1155Errors {
    /**
     * @dev Indicates an error related to the current `balance` of a `sender`. Used in transfers.
     * @param sender Address whose tokens are being transferred.
     * @param balance Current balance for the interacting account.
     * @param needed Minimum amount required to perform a transfer.
     * @param tokenId Identifier number of a token.
     */
    error ERC1155InsufficientBalance(address sender, uint256 balance, uint256 needed, uint256 tokenId);

    /**
     * @dev Indicates a failure with the token `sender`. Used in transfers.
     * @param sender Address whose tokens are being transferred.
     */
    error ERC1155InvalidSender(address sender);

    /**
     * @dev Indicates a failure with the token `receiver`. Used in transfers.
     * @param receiver Address to which tokens are being transferred.
     */
    error ERC1155InvalidReceiver(address receiver);

    /**
     * @dev Indicates a failure with the `operator`’s approval. Used in transfers.
     * @param operator Address that may be allowed to operate on tokens without being their owner.
     * @param owner Address of the current owner of a token.
     */
    error ERC1155MissingApprovalForAll(address operator, address owner);

    /**
     * @dev Indicates a failure with the `approver` of a token to be approved. Used in approvals.
     * @param approver Address initiating an approval operation.
     */
    error ERC1155InvalidApprover(address approver);

    /**
     * @dev Indicates a failure with the `operator` to be approved. Used in approvals.
     * @param operator Address that may be allowed to operate on tokens without being their owner.
     */
    error ERC1155InvalidOperator(address operator);

    /**
     * @dev Indicates an array length mismatch between ids and values in a safeBatchTransferFrom operation.
     * Used in batch transfers.
     * @param idsLength Length of the array of token identifiers
     * @param valuesLength Length of the array of token amounts
     */
    error ERC1155InvalidArrayLength(uint256 idsLength, uint256 valuesLength);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.4.0) (token/ERC20/ERC20.sol)

pragma solidity ^0.8.20;

import {IERC20} from "./IERC20.sol";
import {IERC20Metadata} from "./extensions/IERC20Metadata.sol";
import {Context} from "../../utils/Context.sol";
import {IERC20Errors} from "../../interfaces/draft-IERC6093.sol";

/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.openzeppelin.com/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * The default value of {decimals} is 18. To change this, you should override
 * this function so it returns a different value.
 *
 * We have followed general OpenZeppelin Contracts guidelines: functions revert
 * instead returning `false` on failure. This behavior is nonetheless
 * conventional and does not conflict with the expectations of ERC-20
 * applications.
 */
abstract contract ERC20 is Context, IERC20, IERC20Metadata, IERC20Errors {
    mapping(address account => uint256) private _balances;

    mapping(address account => mapping(address spender => uint256)) private _allowances;

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;

    /**
     * @dev Sets the values for {name} and {symbol}.
     *
     * Both values are immutable: they can only be set once during construction.
     */
    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    /**
     * @dev Returns the name of the token.
     */
    function name() public view virtual returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view virtual returns (string memory) {
        return _symbol;
    }

    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5.05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei. This is the default value returned by this function, unless
     * it's overridden.
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view virtual returns (uint8) {
        return 18;
    }

    /// @inheritdoc IERC20
    function totalSupply() public view virtual returns (uint256) {
        return _totalSupply;
    }

    /// @inheritdoc IERC20
    function balanceOf(address account) public view virtual returns (uint256) {
        return _balances[account];
    }

    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - the caller must have a balance of at least `value`.
     */
    function transfer(address to, uint256 value) public virtual returns (bool) {
        address owner = _msgSender();
        _transfer(owner, to, value);
        return true;
    }

    /// @inheritdoc IERC20
    function allowance(address owner, address spender) public view virtual returns (uint256) {
        return _allowances[owner][spender];
    }

    /**
     * @dev See {IERC20-approve}.
     *
     * NOTE: If `value` is the maximum `uint256`, the allowance is not updated on
     * `transferFrom`. This is semantically equivalent to an infinite approval.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 value) public virtual returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, value);
        return true;
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Skips emitting an {Approval} event indicating an allowance update. This is not
     * required by the ERC. See {xref-ERC20-_approve-address-address-uint256-bool-}[_approve].
     *
     * NOTE: Does not update the allowance if the current allowance
     * is the maximum `uint256`.
     *
     * Requirements:
     *
     * - `from` and `to` cannot be the zero address.
     * - `from` must have a balance of at least `value`.
     * - the caller must have allowance for ``from``'s tokens of at least
     * `value`.
     */
    function transferFrom(address from, address to, uint256 value) public virtual returns (bool) {
        address spender = _msgSender();
        _spendAllowance(from, spender, value);
        _transfer(from, to, value);
        return true;
    }

    /**
     * @dev Moves a `value` amount of tokens from `from` to `to`.
     *
     * This internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * NOTE: This function is not virtual, {_update} should be overridden instead.
     */
    function _transfer(address from, address to, uint256 value) internal {
        if (from == address(0)) {
            revert ERC20InvalidSender(address(0));
        }
        if (to == address(0)) {
            revert ERC20InvalidReceiver(address(0));
        }
        _update(from, to, value);
    }

    /**
     * @dev Transfers a `value` amount of tokens from `from` to `to`, or alternatively mints (or burns) if `from`
     * (or `to`) is the zero address. All customizations to transfers, mints, and burns should be done by overriding
     * this function.
     *
     * Emits a {Transfer} event.
     */
    function _update(address from, address to, uint256 value) internal virtual {
        if (from == address(0)) {
            // Overflow check required: The rest of the code assumes that totalSupply never overflows
            _totalSupply += value;
        } else {
            uint256 fromBalance = _balances[from];
            if (fromBalance < value) {
                revert ERC20InsufficientBalance(from, fromBalance, value);
            }
            unchecked {
                // Overflow not possible: value <= fromBalance <= totalSupply.
                _balances[from] = fromBalance - value;
            }
        }

        if (to == address(0)) {
            unchecked {
                // Overflow not possible: value <= totalSupply or value <= fromBalance <= totalSupply.
                _totalSupply -= value;
            }
        } else {
            unchecked {
                // Overflow not possible: balance + value is at most totalSupply, which we know fits into a uint256.
                _balances[to] += value;
            }
        }

        emit Transfer(from, to, value);
    }

    /**
     * @dev Creates a `value` amount of tokens and assigns them to `account`, by transferring it from address(0).
     * Relies on the `_update` mechanism
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * NOTE: This function is not virtual, {_update} should be overridden instead.
     */
    function _mint(address account, uint256 value) internal {
        if (account == address(0)) {
            revert ERC20InvalidReceiver(address(0));
        }
        _update(address(0), account, value);
    }

    /**
     * @dev Destroys a `value` amount of tokens from `account`, lowering the total supply.
     * Relies on the `_update` mechanism.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * NOTE: This function is not virtual, {_update} should be overridden instead
     */
    function _burn(address account, uint256 value) internal {
        if (account == address(0)) {
            revert ERC20InvalidSender(address(0));
        }
        _update(account, address(0), value);
    }

    /**
     * @dev Sets `value` as the allowance of `spender` over the `owner`'s tokens.
     *
     * This internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     *
     * Overrides to this logic should be done to the variant with an additional `bool emitEvent` argument.
     */
    function _approve(address owner, address spender, uint256 value) internal {
        _approve(owner, spender, value, true);
    }

    /**
     * @dev Variant of {_approve} with an optional flag to enable or disable the {Approval} event.
     *
     * By default (when calling {_approve}) the flag is set to true. On the other hand, approval changes made by
     * `_spendAllowance` during the `transferFrom` operation set the flag to false. This saves gas by not emitting any
     * `Approval` event during `transferFrom` operations.
     *
     * Anyone who wishes to continue emitting `Approval` events on the`transferFrom` operation can force the flag to
     * true using the following override:
     *
     * ```solidity
     * function _approve(address owner, address spender, uint256 value, bool) internal virtual override {
     *     super._approve(owner, spender, value, true);
     * }
     * ```
     *
     * Requirements are the same as {_approve}.
     */
    function _approve(address owner, address spender, uint256 value, bool emitEvent) internal virtual {
        if (owner == address(0)) {
            revert ERC20InvalidApprover(address(0));
        }
        if (spender == address(0)) {
            revert ERC20InvalidSpender(address(0));
        }
        _allowances[owner][spender] = value;
        if (emitEvent) {
            emit Approval(owner, spender, value);
        }
    }

    /**
     * @dev Updates `owner`'s allowance for `spender` based on spent `value`.
     *
     * Does not update the allowance value in case of infinite allowance.
     * Revert if not enough allowance is available.
     *
     * Does not emit an {Approval} event.
     */
    function _spendAllowance(address owner, address spender, uint256 value) internal virtual {
        uint256 currentAllowance = allowance(owner, spender);
        if (currentAllowance < type(uint256).max) {
            if (currentAllowance < value) {
                revert ERC20InsufficientAllowance(spender, currentAllowance, value);
            }
            unchecked {
                _approve(owner, spender, currentAllowance - value, false);
            }
        }
    }
}

// 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);
}

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v5.4.0) (token/ERC20/extensions/IERC20Metadata.sol)

pragma solidity >=0.6.2;

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

/**
 * @dev Interface for the optional metadata functions from the ERC-20 standard.
 */
interface IERC20Metadata is IERC20 {
    /**
     * @dev Returns the name of the token.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the symbol of the token.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the decimals places of the token.
     */
    function decimals() external view returns (uint8);
}

// 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;
    }
}

// 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;
    }
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;

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

// OpenSea integration interfaces
interface IOpenSeaSeaport {
    function fulfillOrder(
        Order calldata order,
        bytes32 fulfillerConduitKey,
        address recipient,
        uint256 maximumFulfilled
    ) external payable returns (bool fulfilled);
    
    function createOrder(
        OrderParameters calldata parameters,
        bytes calldata signature
    ) external returns (bytes32 orderHash);
    
    function getOrderHash(OrderParameters calldata parameters) external view returns (bytes32);
}

interface IERC721 {
    function safeTransferFrom(address from, address to, uint256 tokenId) external;
    function ownerOf(uint256 tokenId) external view returns (address);
    function approve(address to, uint256 tokenId) external;
    function getApproved(uint256 tokenId) external view returns (address);
    function setApprovalForAll(address operator, bool approved) external;
    function isApprovedForAll(address owner, address operator) external view returns (bool);
}

interface IERC1155 {
    function safeTransferFrom(address from, address to, uint256 id, uint256 amount, bytes calldata data) external;
    function balanceOf(address account, uint256 id) external view returns (uint256);
    function setApprovalForAll(address operator, bool approved) external;
    function isApprovedForAll(address account, address operator) external view returns (bool);
}

// OpenSea Seaport Order structure
struct Order {
    address offerer;
    address zone;
    OfferItem[] offer;
    ConsiderationItem[] consideration;
    OrderType orderType;
    uint256 startTime;
    uint256 endTime;
    bytes32 zoneHash;
    uint256 salt;
    bytes32 conduitKey;
    uint256 totalOriginalConsiderationItems;
}

// OpenSea Seaport OrderParameters structure
struct OrderParameters {
    address offerer;
    address zone;
    OfferItem[] offer;
    ConsiderationItem[] consideration;
    OrderType orderType;
    uint256 startTime;
    uint256 endTime;
    bytes32 zoneHash;
    uint256 salt;
    bytes32 conduitKey;
    uint256 totalOriginalConsiderationItems;
}

struct OfferItem {
    ItemType itemType;
    address token;
    uint256 identifierOrCriteria;
    uint256 startAmount;
    uint256 endAmount;
    address recipient;
}

struct ConsiderationItem {
    ItemType itemType;
    address token;
    uint256 identifierOrCriteria;
    uint256 startAmount;
    uint256 endAmount;
    address recipient;
}

enum OrderType {
    FULL_OPEN,
    PARTIAL_OPEN,
    FULL_RESTRICTED,
    PARTIAL_RESTRICTED
}

enum ItemType {
    NATIVE,
    ERC20,
    ERC721,
    ERC1155,
    ERC721_WITH_CRITERIA,
    ERC1155_WITH_CRITERIA
}

contract OpepenStrategy is ERC20, Ownable, ReentrancyGuard {
	// State variables
	bool public isPresaleActive;
	bool public isUnlocked;
	// Price in wei per whole token (1e18 base units)
	uint256 public presalePrice;
	uint256 public constant TREASURY_FEE_PERCENT = 8;
	uint256 public constant DEV_FEE_PERCENT = 1;
	uint256 public constant BURN_FEE_PERCENT = 1;
	uint256 public constant TOTAL_FEE_PERCENT = 10;
	
	address public treasury;
	address public constant BURN_ADDRESS = 0x000000000000000000000000000000000000dEaD;
	address public devWallet;
	
	// OpenSea integration
	address public openseaSeaport;
	address public opepenContract;
	address public backendAPI;
	
	// Opepen floor configuration
	bool public isOpepenFloorEnabled;
	uint256 public opepenFloorSlippage;

	
	// Enhanced Opepen functionality
	mapping(uint256 => uint256) public buyPrices;
	mapping(uint256 => uint256) public purchaseTimes;
	mapping(uint256 => address) public purchasers;
	mapping(uint256 => bytes32) public purchaseOrderHashes;
	mapping(uint256 => bool) public isTokenOwned;
	mapping(uint256 => bool) public isListed;
	mapping(uint256 => uint256) public listingPrices;
	mapping(uint256 => bytes32) public listingOrderHashes;
	mapping(uint256 => uint256) public listingStartTimes;
	mapping(uint256 => uint256) public listingEndTimes;
	mapping(address => bool) public authorizedCallers;
	
	uint256 public totalPurchased;
	uint256 public totalSpent;
	uint256 public averageBuyPrice;
	
	// Events
	event PresaleActivated(uint256 price);
	event PresaleDeactivated();
	event TokensUnlocked();
	event TokensPurchased(address indexed buyer, uint256 amount, uint256 cost);
	event FeesCollected(uint256 treasuryAmount, uint256 devAmount, uint256 burnAmount);
	event BackendAPICalled(address indexed buyer, uint256 tokenId, bool success);
	event BuyPriceSet(uint256 indexed tokenId, uint256 buyPrice, uint256 timestamp);
	event PurchaseValidated(uint256 indexed tokenId, uint256 price, bool isValid, uint256 timestamp);
	event PurchaseOrderCreated(uint256 indexed tokenId, uint256 price, bytes32 orderHash, uint256 timestamp);
	event ListingCreated(uint256 indexed tokenId, uint256 buyPrice, uint256 listingPrice, uint256 startTime, uint256 endTime, bytes32 orderHash);
	event ListingFulfilled(uint256 indexed tokenId, address indexed buyer, uint256 price, uint256 timestamp);
	event NFTReceived(address indexed from, uint256 indexed tokenId, uint256 amount, uint256 timestamp);
	event ETHReceived(address indexed from, uint256 amount, uint256 timestamp);
	event AuthorizedCallerAdded(address indexed caller);
	event AuthorizedCallerRemoved(address indexed caller);
	event DevWalletUpdated(address indexed oldWallet, address indexed newWallet);
	
	// Modifiers
	modifier presaleActive() {
		require(isPresaleActive, "Presale is not active");
		_;
	}
	
	modifier tokensUnlocked() {
		require(isUnlocked, "Tokens are still locked");
		_;
	}
	
	modifier onlyAuthorized() {
		require(authorizedCallers[msg.sender] || msg.sender == owner(), "Not authorized");
		_;
	}
	
	constructor(
		string memory name,
		string memory symbol,
		uint256 initialSupply,
		address _treasury,
		address _devWallet,
		address _openseaSeaport,
		address _opepenContract,
		address _backendAPI
	) ERC20(name, symbol) Ownable(msg.sender) {
		require(_treasury != address(0), "Treasury address cannot be zero");
		require(_devWallet != address(0), "Dev wallet address cannot be zero");
		require(_openseaSeaport != address(0), "OpenSea Seaport address cannot be zero");
		require(_opepenContract != address(0), "Opepen contract address cannot be zero");
		require(_backendAPI != address(0), "Backend API address cannot be zero");
		
		treasury = _treasury;
		devWallet = _devWallet;
		openseaSeaport = _openseaSeaport;
		opepenContract = _opepenContract;
		backendAPI = _backendAPI;
		
		// Set default presale price to 0.000000011 ETH (11 gwei)
		presalePrice = 11000000000; // 0.000000011 ETH in wei
		
		// Initialize Opepen floor configuration
		isOpepenFloorEnabled = false;
		opepenFloorSlippage = 500; // 5% default slippage (500 basis points)
		
		// Mint initial supply to owner (admin)
		_mint(msg.sender, initialSupply);
	}
	
	/**
	 * @dev Activate presale with specified price per whole token (wei)
	 * @param priceWei Price in wei per 1 whole token (1e18 units)
	 */
	function activatePresale(uint256 priceWei) external onlyOwner {
		require(priceWei > 0, "Price must be greater than zero");
		presalePrice = priceWei;
		isPresaleActive = true;
		emit PresaleActivated(priceWei);
	}
	
	/**
	 * @dev Deactivate presale
	 */
	function deactivatePresale() external onlyOwner {
		isPresaleActive = false;
		emit PresaleDeactivated();
	}
	
	/**
	 * @dev Unlock tokens to allow transfers
	 */
	function unlockTokens() external onlyOwner {
		isUnlocked = true;
		emit TokensUnlocked();
	}
	
	/**
	 * @dev Purchase tokens during presale
	 * @param amount Number of tokens to purchase (in base units, 18 decimals)
	 */
	function purchaseTokens(uint256 amount) external payable presaleActive nonReentrant {
		require(amount > 0, "Amount must be greater than zero");
		// requiredETH = amount * presalePrice / 1e18 (price is per whole token)
		uint256 requiredETH = (amount * presalePrice) / 1e18;
		require(msg.value >= requiredETH, "Insufficient ETH sent");
		
		// Check if owner has enough tokens
		require(balanceOf(owner()) >= amount, "Insufficient tokens available for sale");
		
		// Transfer tokens from owner to buyer
		_transfer(owner(), msg.sender, amount);
		
		// Refund excess ETH
		if (msg.value > requiredETH) {
			payable(msg.sender).transfer(msg.value - requiredETH);
		}
		
		emit TokensPurchased(msg.sender, amount, requiredETH);
	}
	
	/**
	 * @dev Override transfer function to add fees and check unlock status
	 */
	function _update(address from, address to, uint256 amount) internal override {
		// Allow minting (from == address(0)) and burning (to == address(0))
		if (from == address(0) || to == address(0)) {
			super._update(from, to, amount);
			return;
		}
		
		// During presale, only allow transfers from owner (for purchases)
		if (!isUnlocked && from != owner()) {
			revert("Tokens are locked and cannot be transferred");
		}
		
		// Apply fees only for regular transfers (not presale purchases)
		if (isUnlocked && from != owner() && to != owner()) {
			uint256 feeAmount = (amount * TOTAL_FEE_PERCENT) / 100;
			uint256 treasuryFee = (amount * TREASURY_FEE_PERCENT) / 100;
			uint256 devFee = (amount * DEV_FEE_PERCENT) / 100;
			uint256 burnFee = (amount * BURN_FEE_PERCENT) / 100;
			
			// Transfer tokens minus fees
			super._update(from, to, amount - feeAmount);
			
			// Transfer treasury fee (goes to treasury wallet)
			super._update(from, treasury, treasuryFee);
			
			// Transfer dev fee (goes to dev wallet)
			super._update(from, devWallet, devFee);
			
			// Burn tokens (transfer to burn address)
			super._update(from, BURN_ADDRESS, burnFee);
			
			emit FeesCollected(treasuryFee, devFee, burnFee);
		} else {
			// No fees for presale purchases or owner transfers
			super._update(from, to, amount);
		}
	}
	
	/**
	 * @dev Update treasury address
	 */
	function setTreasury(address _treasury) external onlyOwner {
		require(_treasury != address(0), "Treasury address cannot be zero");
		treasury = _treasury;
	}
	
	/**
	 * @dev Update dev wallet address
	 */
	function setDevWallet(address _devWallet) external onlyOwner {
		require(_devWallet != address(0), "Dev wallet address cannot be zero");
		address oldWallet = devWallet;
		devWallet = _devWallet;
		emit DevWalletUpdated(oldWallet, _devWallet);
	}
	
	/**
	 * @dev Withdraw ETH from contract (only owner)
	 */
	function withdrawETH() external onlyOwner {
		uint256 balance = address(this).balance;
		require(balance > 0, "No ETH to withdraw");
		payable(owner()).transfer(balance);
	}
	
	/**
	 * @dev Get presale status
	 */
	function getPresaleStatus() external view returns (bool active, bool unlocked, uint256 price) {
		return (isPresaleActive, isUnlocked, presalePrice);
	}
	
	/**
	 * @dev Get available tokens for presale
	 */
	function getAvailableTokensForPresale() external view returns (uint256) {
		return balanceOf(owner());
	}
	
	/**
	 * @dev Update OpenSea Seaport address
	 */
	function setOpenSeaSeaport(address _seaport) external onlyOwner {
		require(_seaport != address(0), "Seaport address cannot be zero");
		openseaSeaport = _seaport;
	}
	
	/**
	 * @dev Update Opepen contract address
	 */
	function setOpepenContract(address _opepen) external onlyOwner {
		require(_opepen != address(0), "Opepen contract address cannot be zero");
		opepenContract = _opepen;
	}
	
	/**
	 * @dev Update backend API address
	 */
	function setBackendAPI(address _api) external onlyOwner {
		require(_api != address(0), "Backend API address cannot be zero");
		backendAPI = _api;
	}
	
	/**
	 * @dev Enable or disable Opepen floor functionality
	 */
	function setOpepenFloorEnabled(bool _enabled) external onlyOwner {
		isOpepenFloorEnabled = _enabled;
	}
	
	/**
	 * @dev Set Opepen floor slippage (in basis points, e.g., 500 = 5%)
	 */
	function setOpepenFloorSlippage(uint256 _slippage) external onlyOwner {
		require(_slippage <= 10000, "Slippage cannot exceed 100%");
		opepenFloorSlippage = _slippage;
	}
	
	/**
	 * @dev Add authorized caller (backend)
	 */
	function addAuthorizedCaller(address caller) external onlyOwner {
		require(caller != address(0), "Caller address cannot be zero");
		authorizedCallers[caller] = true;
		emit AuthorizedCallerAdded(caller);
	}
	
	/**
	 * @dev Remove authorized caller
	 */
	function removeAuthorizedCaller(address caller) external onlyOwner {
		authorizedCallers[caller] = false;
		emit AuthorizedCallerRemoved(caller);
	}
	
	/**
	 * @dev Receive ETH (for sales)
	 */
	receive() external payable {
		emit ETHReceived(msg.sender, msg.value, block.timestamp);
	}
	
	/**
	 * @dev Fallback function
	 */
	fallback() external payable {
		emit ETHReceived(msg.sender, msg.value, block.timestamp);
	}
	
	/**
	 * @dev Get listing information for a token
	 */
	function getListingInfo(uint256 tokenId) external view returns (
		bool listed,
		uint256 price,
		uint256 startTime,
		uint256 endTime,
		bytes32 orderHash
	) {
		return (
			isListed[tokenId],
			listingPrices[tokenId],
			listingStartTimes[tokenId],
			listingEndTimes[tokenId],
			listingOrderHashes[tokenId]
		);
	}
	
	/**
	 * @dev Check if address is authorized caller
	 */
	function isAuthorizedCaller(address caller) external view returns (bool) {
		return authorizedCallers[caller] || caller == owner();
	}
	
	/**
	 * @dev Get contract's ETH balance
	 */
	function getETHBalance() external view returns (uint256) {
		return address(this).balance;
	}
	
	/**
	 * @dev Emergency function to cancel a listing
	 */
	function cancelListing(uint256 tokenId) external onlyOwner {
		require(isListed[tokenId], "Token not listed");
		isListed[tokenId] = false;
		emit ListingCreated(tokenId, buyPrices[tokenId], 0, 0, 0, bytes32(0)); // Emit with 0 values to indicate cancellation
	}
	
	/**
	 * @dev Create Opepen listing (admin only)
	 * This function creates a listing on OpenSea for an NFT owned by the contract
	 */
	function createListing(
		uint256 tokenId,
		uint256 listingPrice,
		uint256 startTime,
		uint256 endTime,
		uint256 salt
	) external onlyOwner returns (bytes32 orderHash) {
		require(isTokenOwned[tokenId], "Token not owned by contract");
		require(buyPrices[tokenId] > 0, "Buy price not set");
		require(!isListed[tokenId], "Token already listed");
		require(listingPrice > 0, "Listing price must be greater than zero");
		require(endTime > startTime, "End time must be after start time");
		require(startTime >= block.timestamp, "Start time must be in the future");
		
		// Create OpenSea Seaport order parameters
		OrderParameters memory orderParams = OrderParameters({
			offerer: address(this),
			zone: address(0), // No zone restriction
			offer: _createOfferItems(tokenId),
			consideration: _createConsiderationItems(listingPrice),
			orderType: OrderType.FULL_OPEN,
			startTime: startTime,
			endTime: endTime,
			zoneHash: bytes32(0),
			salt: salt,
			conduitKey: bytes32(0),
			totalOriginalConsiderationItems: 1
		});
		
		// Get order hash from OpenSea Seaport
		orderHash = IOpenSeaSeaport(openseaSeaport).getOrderHash(orderParams);
		
		// Update listing status
		isListed[tokenId] = true;
		listingPrices[tokenId] = listingPrice;
		listingOrderHashes[tokenId] = orderHash;
		listingStartTimes[tokenId] = startTime;
		listingEndTimes[tokenId] = endTime;
		
		emit ListingCreated(tokenId, buyPrices[tokenId], listingPrice, startTime, endTime, orderHash);
	}
	
	/**
	 * @dev Fulfill a listing (when someone buys the NFT)
	 */
	function fulfillListing(
		uint256 tokenId,
		address buyer
	) external payable onlyAuthorized nonReentrant {
		require(isListed[tokenId], "Token not listed");
		require(block.timestamp >= listingStartTimes[tokenId], "Listing not started");
		require(block.timestamp <= listingEndTimes[tokenId], "Listing expired");
		require(msg.value >= listingPrices[tokenId], "Insufficient payment");
		
		// Transfer NFT to buyer
		IERC721(opepenContract).safeTransferFrom(address(this), buyer, tokenId);
		
		// Update ownership status
		isTokenOwned[tokenId] = false;
		isListed[tokenId] = false;
		
		// Distribute payment
		uint256 listingPrice = listingPrices[tokenId];
		uint256 excess = msg.value - listingPrice;
		
		// Send excess back to buyer
		if (excess > 0) {
			payable(buyer).transfer(excess);
		}
		
		emit ListingFulfilled(tokenId, buyer, listingPrice, block.timestamp);
	}
	
	/**
	 * @dev Receive NFT from user (for listing)
	 */
	function receiveNFT(
		uint256 tokenId,
		uint256 buyPrice
	) external {
		require(IERC721(opepenContract).ownerOf(tokenId) == address(this), "Contract doesn't own token");
		require(buyPrice > 0, "Buy price must be greater than zero");
		
		isTokenOwned[tokenId] = true;
		buyPrices[tokenId] = buyPrice;
		purchaseTimes[tokenId] = block.timestamp;
		purchasers[tokenId] = msg.sender;
		
		emit NFTReceived(msg.sender, tokenId, 1, block.timestamp);
	}
	
	/**
	 * @dev Create offer items for OpenSea order
	 */
	function _createOfferItems(uint256 tokenId) internal view returns (OfferItem[] memory) {
		OfferItem[] memory offer = new OfferItem[](1);
		offer[0] = OfferItem({
			itemType: ItemType.ERC721,
			token: opepenContract,
			identifierOrCriteria: tokenId,
			startAmount: 1,
			endAmount: 1,
			recipient: address(0)
		});
		return offer;
	}
	
	/**
	 * @dev Create consideration items for OpenSea order
	 */
	function _createConsiderationItems(uint256 price) internal view returns (ConsiderationItem[] memory) {
		ConsiderationItem[] memory consideration = new ConsiderationItem[](1);
		consideration[0] = ConsiderationItem({
			itemType: ItemType.NATIVE,
			token: address(0),
			identifierOrCriteria: 0,
			startAmount: price,
			endAmount: price,
			recipient: payable(address(this))
		});
		return consideration;
	}
	
	/**
	 * @dev Get fee configuration
	 */
	function getFeeConfig() external view returns (
		uint256 treasuryFeePercent,
		uint256 devFeePercent,
		uint256 burnFeePercent,
		uint256 totalFeePercent,
		address treasuryAddress,
		address devWalletAddress
	) {
		return (
			TREASURY_FEE_PERCENT,
			DEV_FEE_PERCENT,
			BURN_FEE_PERCENT,
			TOTAL_FEE_PERCENT,
			treasury,
			devWallet
		);
	}
	
	/**
	 * @dev Get Opepen floor configuration
	 */
	function getOpepenFloorConfig() external view returns (
		bool enabled,
		address seaport,
		address opepen,
		address api,
		uint256 slippage
	) {
		return (
			isOpepenFloorEnabled,
			openseaSeaport,
			opepenContract,
			backendAPI,
			opepenFloorSlippage
		);
	}
	
	/**
	 * @dev Get purchase statistics
	 */
	function getPurchaseStats() external view returns (
		uint256 total,
		uint256 spent,
		uint256 average
	) {
		return (
			totalPurchased,
			totalSpent,
			averageBuyPrice
		);
	}
	
	/**
	 * @dev Get purchase history for a token
	 */
	function getPurchaseHistory(uint256 tokenId) external view returns (
		address purchaser,
		uint256 purchaseTime,
		bool owned
	) {
		return (
			purchasers[tokenId],
			purchaseTimes[tokenId],
			isTokenOwned[tokenId]
		);
	}
}