Contract Address Details

// SPDX-License-Identifier: GPL-3.0
pragma solidity ^0.8.20;

// OpenZeppelin Contracts (last updated v5.4.0) (token/ERC20/IERC20.sol)


/**
 * @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 (last updated v5.5.0) (token/ERC20/ERC20.sol)



// OpenZeppelin Contracts (last updated v5.4.0) (token/ERC20/extensions/IERC20Metadata.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);
}

// OpenZeppelin Contracts (last updated v5.0.1) (utils/Context.sol)


/**
 * @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 (last updated v5.5.0) (interfaces/draft-IERC6093.sol)


/**
 * @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-721.
     * 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);
}


/**
 * @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 sets 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);
            }
        }
    }
}

// OpenZeppelin Contracts (last updated v5.5.0) (utils/ReentrancyGuard.sol)


// OpenZeppelin Contracts (last updated v5.1.0) (utils/StorageSlot.sol)
// This file was procedurally generated from scripts/generate/templates/StorageSlot.js.


/**
 * @dev Library for reading and writing primitive types to specific storage slots.
 *
 * Storage slots are often used to avoid storage conflict when dealing with upgradeable contracts.
 * This library helps with reading and writing to such slots without the need for inline assembly.
 *
 * The functions in this library return Slot structs that contain a `value` member that can be used to read or write.
 *
 * Example usage to set ERC-1967 implementation slot:
 * ```solidity
 * contract ERC1967 {
 *     // Define the slot. Alternatively, use the SlotDerivation library to derive the slot.
 *     bytes32 internal constant _IMPLEMENTATION_SLOT = 0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc;
 *
 *     function _getImplementation() internal view returns (address) {
 *         return StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value;
 *     }
 *
 *     function _setImplementation(address newImplementation) internal {
 *         require(newImplementation.code.length > 0);
 *         StorageSlot.getAddressSlot(_IMPLEMENTATION_SLOT).value = newImplementation;
 *     }
 * }
 * ```
 *
 * TIP: Consider using this library along with {SlotDerivation}.
 */
library StorageSlot {
    struct AddressSlot {
        address value;
    }

    struct BooleanSlot {
        bool value;
    }

    struct Bytes32Slot {
        bytes32 value;
    }

    struct Uint256Slot {
        uint256 value;
    }

    struct Int256Slot {
        int256 value;
    }

    struct StringSlot {
        string value;
    }

    struct BytesSlot {
        bytes value;
    }

    /**
     * @dev Returns an `AddressSlot` with member `value` located at `slot`.
     */
    function getAddressSlot(bytes32 slot) internal pure returns (AddressSlot storage r) {
        assembly ("memory-safe") {
            r.slot := slot
        }
    }

    /**
     * @dev Returns a `BooleanSlot` with member `value` located at `slot`.
     */
    function getBooleanSlot(bytes32 slot) internal pure returns (BooleanSlot storage r) {
        assembly ("memory-safe") {
            r.slot := slot
        }
    }

    /**
     * @dev Returns a `Bytes32Slot` with member `value` located at `slot`.
     */
    function getBytes32Slot(bytes32 slot) internal pure returns (Bytes32Slot storage r) {
        assembly ("memory-safe") {
            r.slot := slot
        }
    }

    /**
     * @dev Returns a `Uint256Slot` with member `value` located at `slot`.
     */
    function getUint256Slot(bytes32 slot) internal pure returns (Uint256Slot storage r) {
        assembly ("memory-safe") {
            r.slot := slot
        }
    }

    /**
     * @dev Returns a `Int256Slot` with member `value` located at `slot`.
     */
    function getInt256Slot(bytes32 slot) internal pure returns (Int256Slot storage r) {
        assembly ("memory-safe") {
            r.slot := slot
        }
    }

    /**
     * @dev Returns a `StringSlot` with member `value` located at `slot`.
     */
    function getStringSlot(bytes32 slot) internal pure returns (StringSlot storage r) {
        assembly ("memory-safe") {
            r.slot := slot
        }
    }

    /**
     * @dev Returns an `StringSlot` representation of the string storage pointer `store`.
     */
    function getStringSlot(string storage store) internal pure returns (StringSlot storage r) {
        assembly ("memory-safe") {
            r.slot := store.slot
        }
    }

    /**
     * @dev Returns a `BytesSlot` with member `value` located at `slot`.
     */
    function getBytesSlot(bytes32 slot) internal pure returns (BytesSlot storage r) {
        assembly ("memory-safe") {
            r.slot := slot
        }
    }

    /**
     * @dev Returns an `BytesSlot` representation of the bytes storage pointer `store`.
     */
    function getBytesSlot(bytes storage store) internal pure returns (BytesSlot storage r) {
        assembly ("memory-safe") {
            r.slot := store.slot
        }
    }
}


/**
 * @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].
 *
 * IMPORTANT: Deprecated. This storage-based reentrancy guard will be removed and replaced
 * by the {ReentrancyGuardTransient} variant in v6.0.
 *
 * @custom:stateless
 */
abstract contract ReentrancyGuard {
    using StorageSlot for bytes32;

    // keccak256(abi.encode(uint256(keccak256("openzeppelin.storage.ReentrancyGuard")) - 1)) & ~bytes32(uint256(0xff))
    bytes32 private constant REENTRANCY_GUARD_STORAGE =
        0x9b779b17422d0df92223018b32b4d1fa46e071723d6817e2486d003becc55f00;

    // 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;

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

    constructor() {
        _reentrancyGuardStorageSlot().getUint256Slot().value = 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();
    }

    /**
     * @dev A `view` only version of {nonReentrant}. Use to block view functions
     * from being called, preventing reading from inconsistent contract state.
     *
     * CAUTION: This is a "view" modifier and does not change the reentrancy
     * status. Use it only on view functions. For payable or non-payable functions,
     * use the standard {nonReentrant} modifier instead.
     */
    modifier nonReentrantView() {
        _nonReentrantBeforeView();
        _;
    }

    function _nonReentrantBeforeView() private view {
        if (_reentrancyGuardEntered()) {
            revert ReentrancyGuardReentrantCall();
        }
    }

    function _nonReentrantBefore() private {
        // On the first call to nonReentrant, _status will be NOT_ENTERED
        _nonReentrantBeforeView();

        // Any calls to nonReentrant after this point will fail
        _reentrancyGuardStorageSlot().getUint256Slot().value = ENTERED;
    }

    function _nonReentrantAfter() private {
        // By storing the original value once again, a refund is triggered (see
        // https://eips.ethereum.org/EIPS/eip-2200)
        _reentrancyGuardStorageSlot().getUint256Slot().value = 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 _reentrancyGuardStorageSlot().getUint256Slot().value == ENTERED;
    }

    function _reentrancyGuardStorageSlot() internal pure virtual returns (bytes32) {
        return REENTRANCY_GUARD_STORAGE;
    }
}

// OpenZeppelin Contracts (last updated v5.3.0) (utils/Pausable.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());
    }
}


/// @title CargoMath — Safe math utilities for AMM calculations
library CargoMath {
    /// @notice Returns the minimum of two uint256 values
    function min(uint256 x, uint256 y) internal pure returns (uint256 z) {
        z = x < y ? x : y;
    }

    /// @notice Babylonian method for integer square root
    /// @dev Accurate for all uint256 inputs, gas-optimized
    function sqrt(uint256 y) internal pure returns (uint256 z) {
        if (y > 3) {
            z = y;
            uint256 x = y;
            if (y > 0xffffffffffffffffffffffffffffffff) { x >>= 128; z >>= 64; }
            if (x > 0xffffffffffffffff) { x >>= 64; z >>= 32; }
            if (x > 0xffffffff) { x >>= 32; z >>= 16; }
            if (x > 0xffff) { x >>= 16; z >>= 8; }
            if (x > 0xff) { x >>= 8; z >>= 4; }
            if (x > 0xf) { x >>= 4; z >>= 2; }
            if (x > 0x3) { z >>= 1; }
            z = (z + y / z) >> 1;
            z = (z + y / z) >> 1;
            z = (z + y / z) >> 1;
            z = (z + y / z) >> 1;
            z = (z + y / z) >> 1;
            z = (z + y / z) >> 1;
            z = (z + y / z) >> 1;
            uint256 z1 = y / z;
            if (z > z1) z = z1;
        } else if (y != 0) {
            z = 1;
        }
    }
}


/// @title ICargoFactory — Factory Interface
/// @notice Interface for CargoFactory fee configuration
interface ICargoFactory {
    function feeTo() external view returns (address);
    function feeToSetter() external view returns (address);
    function allPairsLength() external view returns (uint256);
    function owner() external view returns (address);
}


/// @title CargoPair — AMM Liquidity Pool
/// @notice Uniswap V2 fork with ETH/native token support
/// @dev WARNING: TWAP oracle is for internal use only. Use Chainlink for external pricing.
contract CargoPair is ERC20, ReentrancyGuard, Pausable {
    using CargoMath for uint256;

    // ── Errors ──────────────────────────────────────────────────────────
    error NotInitialized();
    error AlreadyInitialized();
    error Forbidden();
    error Expired();
    error ZeroValue();
    error ZeroAddress();
    error InsufficientInput();
    error InsufficientOutput();
    error InsufficientLiquidity();
    error InsufficientLiquidityMinted();
    error InsufficientLiquidityBurned();
    error InsufficientCargoOut();
    error InsufficientTokenOut();
    error InsufficientTokenAmount();
    error NoLiquidity();
    error StaleReservesSync();
    error CargoTransferFailed();
    error TokenTransferFailed();
    error LiquidityTooLow();
    error PairedContractReverted();

    // ── Events ──────────────────────────────────────────────────────────
    event Mint(address indexed sender, uint256 amountCargo, uint256 amountToken);
    event Burn(address indexed sender, uint256 amountCargo, uint256 amountToken, address indexed to);
    event Swap(
        address indexed sender,
        uint256 amountCargoIn,
        uint256 amountTokenIn,
        uint256 amountCargoOut,
        uint256 amountTokenOut,
        address indexed to
    );
    event Sync(uint256 reserveCargo, uint256 reserveToken);
    event PermanentLiquidityBurned(uint256 amount);
    event Initialized(address indexed token);
    event PairSkimmed(address indexed to, uint256 cargoAmount, uint256 tokenAmount);

    // ── State ───────────────────────────────────────────────────────────
    address public factory;
    address public token;
    bool private _initialized;

    uint256 private constant MINIMUM_LIQUIDITY = 10 ** 3;
    uint256 private constant FEE_NUMERATOR = 997;
    uint256 private constant FEE_DENOMINATOR = 1000;

    uint256 public reserveCargo;
    uint256 public reserveToken;

    uint256 public price0CumulativeLast;
    uint256 public price1CumulativeLast;
    uint256 public kLast;

    uint256 private _blockTimestampLast;

    // ── Modifiers ───────────────────────────────────────────────────────
    modifier onlyFactory() {
        // Allow factory contract OR factory owner
        if (msg.sender != factory && msg.sender != ICargoFactory(factory).owner()) revert Forbidden();
        _;
    }

    modifier initialized() {
        if (!_initialized) revert NotInitialized();
        _;
    }

    modifier checkDeadline(uint256 deadline) {
        if (block.timestamp > deadline) revert Expired();
        _;
    }

    // ── Constructor ─────────────────────────────────────────────────────
    constructor() ERC20("Cargo Liquidity Provider", "CARGO-LP") {
        factory = msg.sender;
    }

    // ── Initialization ──────────────────────────────────────────────────
    function initialize(address _token) external {
        if (_initialized) revert AlreadyInitialized();
        if (_token == address(0)) revert ZeroAddress();
        token = _token;
        _initialized = true;
        emit Initialized(_token);
    }

    // ── View Functions ──────────────────────────────────────────────────
    function getReserves() public view returns (uint256 cargo, uint256 tokenAmt, uint256 ts) {
        cargo = reserveCargo;
        tokenAmt = reserveToken;
        ts = _blockTimestampLast;
    }

    // ── Internal Functions ──────────────────────────────────────────────
    function _update(uint256 balanceCargo, uint256 balanceToken) private {
        uint256 timeElapsed = block.timestamp - _blockTimestampLast;
        if (timeElapsed > 0 && reserveCargo != 0 && reserveToken != 0) {
            unchecked {
                price0CumulativeLast += (reserveToken * timeElapsed) / reserveCargo;
                price1CumulativeLast += (reserveCargo * timeElapsed) / reserveToken;
            }
        }
        reserveCargo = balanceCargo;
        reserveToken = balanceToken;
        _blockTimestampLast = block.timestamp;
        emit Sync(reserveCargo, reserveToken);
    }

    function _mintFee(uint256 _reserveCargo, uint256 _reserveToken) private returns (bool feeOn) {
        address feeTo = ICargoFactory(factory).feeTo();
        feeOn = feeTo != address(0);
        uint256 _kLast = kLast;
        if (feeOn) {
            if (_kLast != 0) {
                uint256 rootK = CargoMath.sqrt(_reserveCargo * _reserveToken);
                uint256 rootKLast = CargoMath.sqrt(_kLast);
                if (rootK > rootKLast) {
                    uint256 numerator = totalSupply() * (rootK - rootKLast);
                    uint256 denominator = rootK * 5 + rootKLast;
                    uint256 liquidity = numerator / denominator;
                    if (liquidity > 0) _mint(feeTo, liquidity);
                }
            }
        } else if (_kLast != 0) {
            kLast = 0;
        }
    }

    function _safeTransfer(address tokenAddr, address to, uint256 value) private {
        (bool success, bytes memory data) = tokenAddr.call(
            abi.encodeWithSelector(IERC20.transfer.selector, to, value)
        );
        if (!success || (data.length != 0 && !abi.decode(data, (bool)))) revert TokenTransferFailed();
    }

    function _safeTransferFrom(address tokenAddr, address from, address to, uint256 value) private {
        (bool success, bytes memory data) = tokenAddr.call(
            abi.encodeWithSelector(IERC20.transferFrom.selector, from, to, value)
        );
        if (!success || (data.length != 0 && !abi.decode(data, (bool)))) revert TokenTransferFailed();
    }

    /// @notice Safe ETH transfer with failure handling
    /// @dev Uses call with success check — reverts on failure to protect users
    function _safeTransferETH(address to, uint256 value) private {
        (bool success, ) = payable(to).call{value: value}("");
        if (!success) revert CargoTransferFailed();
    }

    // ── Liquidity Functions ─────────────────────────────────────────────
    function addLiquidity(
        address to,
        uint256 maxTokenIn,
        uint256 deadline
    ) external payable nonReentrant initialized whenNotPaused checkDeadline(deadline) returns (uint256 liquidity, uint256 tokenUsed) {
        if (to == address(0)) revert ZeroAddress();
        if (msg.value == 0) revert ZeroValue();
        if (maxTokenIn == 0) revert InsufficientInput();

        uint256 _reserveCargo = reserveCargo;
        uint256 _reserveToken = reserveToken;

        if (_reserveCargo == 0 && _reserveToken == 0) {
            require(maxTokenIn > 0, "CargoPair: INITIAL_TOKEN_REQUIRED");
            _safeTransferFrom(token, msg.sender, address(this), maxTokenIn);
            tokenUsed = maxTokenIn;
        } else {
            if (_reserveCargo == 0) revert StaleReservesSync();
            uint256 optimalToken = (msg.value * _reserveToken) / _reserveCargo;
            if (optimalToken > maxTokenIn) revert InsufficientTokenAmount();
            if (optimalToken == 0) revert InsufficientInput();
            _safeTransferFrom(token, msg.sender, address(this), optimalToken);
            tokenUsed = optimalToken;
        }

        uint256 balanceCargo = address(this).balance;
        uint256 balanceToken = IERC20(token).balanceOf(address(this));
        uint256 amountCargo = balanceCargo - _reserveCargo;
        uint256 amountToken = balanceToken - _reserveToken;

        _mintFee(_reserveCargo, _reserveToken);

        uint256 _totalSupply = totalSupply();
        if (_totalSupply == 0) {
            uint256 rootK = CargoMath.sqrt(amountCargo * amountToken);
            if (rootK <= MINIMUM_LIQUIDITY) revert LiquidityTooLow();
            liquidity = rootK - MINIMUM_LIQUIDITY;
            _mint(0x000000000000000000000000000000000000dEaD, MINIMUM_LIQUIDITY);
            emit PermanentLiquidityBurned(MINIMUM_LIQUIDITY);
        } else {
            liquidity = CargoMath.min(
                (amountCargo * _totalSupply) / _reserveCargo,
                (amountToken * _totalSupply) / _reserveToken
            );
        }
        if (liquidity == 0) revert InsufficientLiquidityMinted();

        _mint(to, liquidity);
        _update(balanceCargo, balanceToken);
        kLast = reserveCargo * reserveToken;
        emit Mint(msg.sender, amountCargo, amountToken);
    }

    function removeLiquidity(
        uint256 liquidity,
        address to,
        uint256 deadline
    ) external nonReentrant initialized whenNotPaused checkDeadline(deadline) returns (uint256 amountCargo, uint256 amountToken) {
        if (to == address(0)) revert ZeroAddress();
        if (liquidity == 0) revert InsufficientLiquidityBurned();
        if (balanceOf(msg.sender) < liquidity) revert InsufficientLiquidityBurned();

        uint256 balanceCargo = address(this).balance;
        uint256 balanceToken = IERC20(token).balanceOf(address(this));

        _mintFee(reserveCargo, reserveToken);

        uint256 _totalSupply = totalSupply();
        amountCargo = (liquidity * balanceCargo) / _totalSupply;
        amountToken = (liquidity * balanceToken) / _totalSupply;

        if (amountCargo == 0) revert InsufficientCargoOut();
        if (amountToken == 0) revert InsufficientTokenOut();

        _burn(msg.sender, liquidity);

        _safeTransfer(token, to, amountToken);
        _safeTransferETH(to, amountCargo);

        balanceCargo = address(this).balance;
        balanceToken = IERC20(token).balanceOf(address(this));

        _update(balanceCargo, balanceToken);
        kLast = reserveCargo * reserveToken;
        emit Burn(msg.sender, amountCargo, amountToken, to);
    }

    // ── Swap Functions ──────────────────────────────────────────────────
    function swapExactCargoForTokens(
        uint256 amountOutMin,
        address to,
        uint256 deadline
    ) external payable nonReentrant initialized whenNotPaused checkDeadline(deadline) returns (uint256 amountOut) {
        if (to == address(0)) revert ZeroAddress();
        uint256 amountIn = msg.value;
        if (amountIn == 0) revert ZeroValue();

        uint256 _reserveCargo = reserveCargo;
        uint256 _reserveToken = reserveToken;
        if (_reserveCargo == 0 || _reserveToken == 0) revert NoLiquidity();

        amountOut = (amountIn * FEE_NUMERATOR * _reserveToken) /
            ((_reserveCargo * FEE_DENOMINATOR) + (amountIn * FEE_NUMERATOR));

        if (amountOut < amountOutMin) revert InsufficientOutput();
        if (amountOut >= _reserveToken) revert InsufficientLiquidity();

        _safeTransfer(token, to, amountOut);
        _update(address(this).balance, IERC20(token).balanceOf(address(this)));
        emit Swap(msg.sender, amountIn, 0, 0, amountOut, to);
    }

    function swapExactTokensForCargo(
        uint256 amountIn,
        uint256 amountOutMin,
        address to,
        uint256 deadline
    ) external nonReentrant initialized whenNotPaused checkDeadline(deadline) returns (uint256 amountOut) {
        if (to == address(0)) revert ZeroAddress();
        if (amountIn == 0) revert ZeroValue();

        _safeTransferFrom(token, msg.sender, address(this), amountIn);

        uint256 _reserveCargo = reserveCargo;
        uint256 _reserveToken = reserveToken;
        if (_reserveCargo == 0 || _reserveToken == 0) revert NoLiquidity();

        amountOut = (amountIn * FEE_NUMERATOR * _reserveCargo) /
            ((_reserveToken * FEE_DENOMINATOR) + (amountIn * FEE_NUMERATOR));

        if (amountOut < amountOutMin) revert InsufficientOutput();
        if (amountOut >= _reserveCargo) revert InsufficientLiquidity();

        _safeTransferETH(to, amountOut);

        _update(address(this).balance, IERC20(token).balanceOf(address(this)));
        emit Swap(msg.sender, 0, amountIn, amountOut, 0, to);
    }

    // ── Admin Functions ─────────────────────────────────────────────────
    /// @notice Skim excess tokens/ETH to owner only
    /// @dev Restricted to factory owner to prevent griefing
    function skim(address to) external nonReentrant onlyFactory {
        if (to == address(0)) revert ZeroAddress();
        address _token = token;
        uint256 tokenBalance = IERC20(_token).balanceOf(address(this));
        uint256 cargoBalance = address(this).balance;
        uint256 tExcess = tokenBalance > reserveToken ? tokenBalance - reserveToken : 0;
        uint256 cExcess = cargoBalance > reserveCargo ? cargoBalance - reserveCargo : 0;
        if (tExcess > 0) {
            _safeTransfer(_token, to, tExcess);
        }
        if (cExcess > 0) {
            _safeTransferETH(to, cExcess);
        }
        emit PairSkimmed(to, cExcess, tExcess);
    }

    function sync() external nonReentrant onlyFactory {
        _update(address(this).balance, IERC20(token).balanceOf(address(this)));
    }

    function pause() external onlyFactory {
        _pause();
    }

    function unpause() external onlyFactory {
        _unpause();
    }

    // ── Receive ─────────────────────────────────────────────────────────
    receive() external payable {}
}