// File: lib/openzeppelin-contracts-upgradeable/contracts/access/OwnableUpgradeable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)

pragma solidity ^0.8.0;

import "../utils/ContextUpgradeable.sol";
import "../proxy/utils/Initializable.sol";

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract OwnableUpgradeable is Initializable, ContextUpgradeable {
    address private _owner;

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

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    function __Ownable_init() internal onlyInitializing {
        __Ownable_init_unchained();
    }

    function __Ownable_init_unchained() internal onlyInitializing {
        _transferOwnership(_msgSender());
    }

    /**
     * @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 {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

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

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[49] private __gap;
}

// File: lib/openzeppelin-contracts-upgradeable/contracts/proxy/utils/Initializable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.1) (proxy/utils/Initializable.sol)

pragma solidity ^0.8.2;

import "../../utils/AddressUpgradeable.sol";

/**
 * @dev This is a base contract to aid in writing upgradeable contracts, or any kind of contract that will be deployed
 * behind a proxy. Since proxied contracts do not make use of a constructor, it's common to move constructor logic to an
 * external initializer function, usually called `initialize`. It then becomes necessary to protect this initializer
 * function so it can only be called once. The {initializer} modifier provided by this contract will have this effect.
 *
 * The initialization functions use a version number. Once a version number is used, it is consumed and cannot be
 * reused. This mechanism prevents re-execution of each "step" but allows the creation of new initialization steps in
 * case an upgrade adds a module that needs to be initialized.
 *
 * For example:
 *
 * [.hljs-theme-light.nopadding]
 * ```
 * contract MyToken is ERC20Upgradeable {
 *     function initialize() initializer public {
 *         __ERC20_init("MyToken", "MTK");
 *     }
 * }
 * contract MyTokenV2 is MyToken, ERC20PermitUpgradeable {
 *     function initializeV2() reinitializer(2) public {
 *         __ERC20Permit_init("MyToken");
 *     }
 * }
 * ```
 *
 * TIP: To avoid leaving the proxy in an uninitialized state, the initializer function should be called as early as
 * possible by providing the encoded function call as the `_data` argument to {ERC1967Proxy-constructor}.
 *
 * CAUTION: When used with inheritance, manual care must be taken to not invoke a parent initializer twice, or to ensure
 * that all initializers are idempotent. This is not verified automatically as constructors are by Solidity.
 *
 * [CAUTION]
 * ====
 * Avoid leaving a contract uninitialized.
 *
 * An uninitialized contract can be taken over by an attacker. This applies to both a proxy and its implementation
 * contract, which may impact the proxy. To prevent the implementation contract from being used, you should invoke
 * the {_disableInitializers} function in the constructor to automatically lock it when it is deployed:
 *
 * [.hljs-theme-light.nopadding]
 * ```
 * /// @custom:oz-upgrades-unsafe-allow constructor
 * constructor() {
 *     _disableInitializers();
 * }
 * ```
 * ====
 */
abstract contract Initializable {
    /**
     * @dev Indicates that the contract has been initialized.
     * @custom:oz-retyped-from bool
     */
    uint8 private _initialized;

    /**
     * @dev Indicates that the contract is in the process of being initialized.
     */
    bool private _initializing;

    /**
     * @dev Triggered when the contract has been initialized or reinitialized.
     */
    event Initialized(uint8 version);

    /**
     * @dev A modifier that defines a protected initializer function that can be invoked at most once. In its scope,
     * `onlyInitializing` functions can be used to initialize parent contracts.
     *
     * Similar to `reinitializer(1)`, except that functions marked with `initializer` can be nested in the context of a
     * constructor.
     *
     * Emits an {Initialized} event.
     */
    modifier initializer() {
        bool isTopLevelCall = !_initializing;
        require(
            (isTopLevelCall && _initialized < 1) || (!AddressUpgradeable.isContract(address(this)) && _initialized == 1),
            "Initializable: contract is already initialized"
        );
        _initialized = 1;
        if (isTopLevelCall) {
            _initializing = true;
        }
        _;
        if (isTopLevelCall) {
            _initializing = false;
            emit Initialized(1);
        }
    }

    /**
     * @dev A modifier that defines a protected reinitializer function that can be invoked at most once, and only if the
     * contract hasn't been initialized to a greater version before. In its scope, `onlyInitializing` functions can be
     * used to initialize parent contracts.
     *
     * A reinitializer may be used after the original initialization step. This is essential to configure modules that
     * are added through upgrades and that require initialization.
     *
     * When `version` is 1, this modifier is similar to `initializer`, except that functions marked with `reinitializer`
     * cannot be nested. If one is invoked in the context of another, execution will revert.
     *
     * Note that versions can jump in increments greater than 1; this implies that if multiple reinitializers coexist in
     * a contract, executing them in the right order is up to the developer or operator.
     *
     * WARNING: setting the version to 255 will prevent any future reinitialization.
     *
     * Emits an {Initialized} event.
     */
    modifier reinitializer(uint8 version) {
        require(!_initializing && _initialized < version, "Initializable: contract is already initialized");
        _initialized = version;
        _initializing = true;
        _;
        _initializing = false;
        emit Initialized(version);
    }

    /**
     * @dev Modifier to protect an initialization function so that it can only be invoked by functions with the
     * {initializer} and {reinitializer} modifiers, directly or indirectly.
     */
    modifier onlyInitializing() {
        require(_initializing, "Initializable: contract is not initializing");
        _;
    }

    /**
     * @dev Locks the contract, preventing any future reinitialization. This cannot be part of an initializer call.
     * Calling this in the constructor of a contract will prevent that contract from being initialized or reinitialized
     * to any version. It is recommended to use this to lock implementation contracts that are designed to be called
     * through proxies.
     *
     * Emits an {Initialized} event the first time it is successfully executed.
     */
    function _disableInitializers() internal virtual {
        require(!_initializing, "Initializable: contract is initializing");
        if (_initialized < type(uint8).max) {
            _initialized = type(uint8).max;
            emit Initialized(type(uint8).max);
        }
    }

    /**
     * @dev Returns the highest version that has been initialized. See {reinitializer}.
     */
    function _getInitializedVersion() internal view returns (uint8) {
        return _initialized;
    }

    /**
     * @dev Returns `true` if the contract is currently initializing. See {onlyInitializing}.
     */
    function _isInitializing() internal view returns (bool) {
        return _initializing;
    }
}

// File: lib/openzeppelin-contracts-upgradeable/contracts/token/ERC20/ERC20Upgradeable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (token/ERC20/ERC20.sol)

pragma solidity ^0.8.0;

import "./IERC20Upgradeable.sol";
import "./extensions/IERC20MetadataUpgradeable.sol";
import "../../utils/ContextUpgradeable.sol";
import "../../proxy/utils/Initializable.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}.
 * For a generic mechanism see {ERC20PresetMinterPauser}.
 *
 * 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].
 *
 * 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 ERC20
 * applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
contract ERC20Upgradeable is Initializable, ContextUpgradeable, IERC20Upgradeable, IERC20MetadataUpgradeable {
    mapping(address => uint256) private _balances;

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

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;

    /**
     * @dev Sets the values for {name} and {symbol}.
     *
     * The default value of {decimals} is 18. To select a different value for
     * {decimals} you should overload it.
     *
     * All two of these values are immutable: they can only be set once during
     * construction.
     */
    function __ERC20_init(string memory name_, string memory symbol_) internal onlyInitializing {
        __ERC20_init_unchained(name_, symbol_);
    }

    function __ERC20_init_unchained(string memory name_, string memory symbol_) internal onlyInitializing {
        _name = name_;
        _symbol = symbol_;
    }

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

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view virtual override 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 value {ERC20} uses, unless this function is
     * 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 override returns (uint8) {
        return 18;
    }

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view virtual override 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 `amount`.
     */
    function transfer(address to, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _transfer(owner, to, amount);
        return true;
    }

    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }

    /**
     * @dev See {IERC20-approve}.
     *
     * NOTE: If `amount` 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 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, amount);
        return true;
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20}.
     *
     * 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 `amount`.
     * - the caller must have allowance for ``from``'s tokens of at least
     * `amount`.
     */
    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) public virtual override returns (bool) {
        address spender = _msgSender();
        _spendAllowance(from, spender, amount);
        _transfer(from, to, amount);
        return true;
    }

    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, allowance(owner, spender) + addedValue);
        return true;
    }

    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        address owner = _msgSender();
        uint256 currentAllowance = allowance(owner, spender);
        require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
        unchecked {
            _approve(owner, spender, currentAllowance - subtractedValue);
        }

        return true;
    }

    /**
     * @dev Moves `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.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `from` must have a balance of at least `amount`.
     */
    function _transfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {
        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");

        _beforeTokenTransfer(from, to, amount);

        uint256 fromBalance = _balances[from];
        require(fromBalance >= amount, "ERC20: transfer amount exceeds balance");
        unchecked {
            _balances[from] = fromBalance - amount;
            // Overflow not possible: the sum of all balances is capped by totalSupply, and the sum is preserved by
            // decrementing then incrementing.
            _balances[to] += amount;
        }

        emit Transfer(from, to, amount);

        _afterTokenTransfer(from, to, amount);
    }

    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     */
    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _beforeTokenTransfer(address(0), account, amount);

        _totalSupply += amount;
        unchecked {
            // Overflow not possible: balance + amount is at most totalSupply + amount, which is checked above.
            _balances[account] += amount;
        }
        emit Transfer(address(0), account, amount);

        _afterTokenTransfer(address(0), account, amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");

        _beforeTokenTransfer(account, address(0), amount);

        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
        unchecked {
            _balances[account] = accountBalance - amount;
            // Overflow not possible: amount <= accountBalance <= totalSupply.
            _totalSupply -= amount;
        }

        emit Transfer(account, address(0), amount);

        _afterTokenTransfer(account, address(0), amount);
    }

    /**
     * @dev Sets `amount` 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.
     */
    function _approve(
        address owner,
        address spender,
        uint256 amount
    ) internal virtual {
        require(owner != address(0), "ERC20: approve from the zero address");
        require(spender != address(0), "ERC20: approve to the zero address");

        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
    }

    /**
     * @dev Updates `owner` s allowance for `spender` based on spent `amount`.
     *
     * Does not update the allowance amount in case of infinite allowance.
     * Revert if not enough allowance is available.
     *
     * Might emit an {Approval} event.
     */
    function _spendAllowance(
        address owner,
        address spender,
        uint256 amount
    ) internal virtual {
        uint256 currentAllowance = allowance(owner, spender);
        if (currentAllowance != type(uint256).max) {
            require(currentAllowance >= amount, "ERC20: insufficient allowance");
            unchecked {
                _approve(owner, spender, currentAllowance - amount);
            }
        }
    }

    /**
     * @dev Hook that is called before any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * will be transferred to `to`.
     * - when `from` is zero, `amount` tokens will be minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}

    /**
     * @dev Hook that is called after any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * has been transferred to `to`.
     * - when `from` is zero, `amount` tokens have been minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens have been burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _afterTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[45] private __gap;
}

// File: lib/openzeppelin-contracts-upgradeable/contracts/token/ERC20/extensions/IERC20MetadataUpgradeable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)

pragma solidity ^0.8.0;

import "../IERC20Upgradeable.sol";

/**
 * @dev Interface for the optional metadata functions from the ERC20 standard.
 *
 * _Available since v4.1._
 */
interface IERC20MetadataUpgradeable is IERC20Upgradeable {
    /**
     * @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);
}

// File: lib/openzeppelin-contracts-upgradeable/contracts/token/ERC20/IERC20Upgradeable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20Upgradeable {
    /**
     * @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 amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

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

    /**
     * @dev Moves `amount` tokens from the caller's account to `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `from` to `to` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) external returns (bool);
}

// File: lib/openzeppelin-contracts-upgradeable/contracts/utils/AddressUpgradeable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (utils/Address.sol)

pragma solidity ^0.8.1;

/**
 * @dev Collection of functions related to the address type
 */
library AddressUpgradeable {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     *
     * [IMPORTANT]
     * ====
     * You shouldn't rely on `isContract` to protect against flash loan attacks!
     *
     * Preventing calls from contracts is highly discouraged. It breaks composability, breaks support for smart wallets
     * like Gnosis Safe, and does not provide security since it can be circumvented by calling from a contract
     * constructor.
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // This method relies on extcodesize/address.code.length, which returns 0
        // for contracts in construction, since the code is only stored at the end
        // of the constructor execution.

        return account.code.length > 0;
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        (bool success, ) = recipient.call{value: amount}("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain `call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value
    ) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(
        address target,
        bytes memory data,
        uint256 value,
        string memory errorMessage
    ) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        (bool success, bytes memory returndata) = target.call{value: value}(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(address target, bytes memory data) internal view returns (bytes memory) {
        return functionStaticCall(target, data, "Address: low-level static call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a static call.
     *
     * _Available since v3.3._
     */
    function functionStaticCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        (bool success, bytes memory returndata) = target.staticcall(data);
        return verifyCallResultFromTarget(target, success, returndata, errorMessage);
    }

    /**
     * @dev Tool to verify that a low level call to smart-contract was successful, and revert (either by bubbling
     * the revert reason or using the provided one) in case of unsuccessful call or if target was not a contract.
     *
     * _Available since v4.8._
     */
    function verifyCallResultFromTarget(
        address target,
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal view returns (bytes memory) {
        if (success) {
            if (returndata.length == 0) {
                // only check isContract if the call was successful and the return data is empty
                // otherwise we already know that it was a contract
                require(isContract(target), "Address: call to non-contract");
            }
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    /**
     * @dev Tool to verify that a low level call was successful, and revert if it wasn't, either by bubbling the
     * revert reason or using the provided one.
     *
     * _Available since v4.3._
     */
    function verifyCallResult(
        bool success,
        bytes memory returndata,
        string memory errorMessage
    ) internal pure returns (bytes memory) {
        if (success) {
            return returndata;
        } else {
            _revert(returndata, errorMessage);
        }
    }

    function _revert(bytes memory returndata, string memory errorMessage) private pure {
        // Look for revert reason and bubble it up if present
        if (returndata.length > 0) {
            // The easiest way to bubble the revert reason is using memory via assembly
            /// @solidity memory-safe-assembly
            assembly {
                let returndata_size := mload(returndata)
                revert(add(32, returndata), returndata_size)
            }
        } else {
            revert(errorMessage);
        }
    }
}

// File: lib/openzeppelin-contracts-upgradeable/contracts/utils/ContextUpgradeable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;
import "../proxy/utils/Initializable.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 ContextUpgradeable is Initializable {
    function __Context_init() internal onlyInitializing {
    }

    function __Context_init_unchained() internal onlyInitializing {
    }
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }

    /**
     * @dev This empty reserved space is put in place to allow future versions to add new
     * variables without shifting down storage in the inheritance chain.
     * See https://docs.openzeppelin.com/contracts/4.x/upgradeable#storage_gaps
     */
    uint256[50] private __gap;
}

// File: lib/openzeppelin-contracts/contracts/access/Ownable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)

pragma solidity ^0.8.0;

import "../utils/Context.sol";

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

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

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }

    /**
     * @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 {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

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

// File: lib/openzeppelin-contracts/contracts/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
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 amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

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

    /**
     * @dev Moves `amount` tokens from the caller's account to `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `from` to `to` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) external returns (bool);
}

// File: lib/openzeppelin-contracts/contracts/utils/Context.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with 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;
    }
}

// File: lib/openzeppelin-contracts/contracts/utils/cryptography/ECDSA.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (utils/cryptography/ECDSA.sol)

pragma solidity ^0.8.0;

import "../Strings.sol";

/**
 * @dev Elliptic Curve Digital Signature Algorithm (ECDSA) operations.
 *
 * These functions can be used to verify that a message was signed by the holder
 * of the private keys of a given address.
 */
library ECDSA {
    enum RecoverError {
        NoError,
        InvalidSignature,
        InvalidSignatureLength,
        InvalidSignatureS,
        InvalidSignatureV // Deprecated in v4.8
    }

    function _throwError(RecoverError error) private pure {
        if (error == RecoverError.NoError) {
            return; // no error: do nothing
        } else if (error == RecoverError.InvalidSignature) {
            revert("ECDSA: invalid signature");
        } else if (error == RecoverError.InvalidSignatureLength) {
            revert("ECDSA: invalid signature length");
        } else if (error == RecoverError.InvalidSignatureS) {
            revert("ECDSA: invalid signature 's' value");
        }
    }

    /**
     * @dev Returns the address that signed a hashed message (`hash`) with
     * `signature` or error string. This address can then be used for verification purposes.
     *
     * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     * this is by receiving a hash of the original message (which may otherwise
     * be too long), and then calling {toEthSignedMessageHash} on it.
     *
     * Documentation for signature generation:
     * - with https://web3js.readthedocs.io/en/v1.3.4/web3-eth-accounts.html#sign[Web3.js]
     * - with https://docs.ethers.io/v5/api/signer/#Signer-signMessage[ethers]
     *
     * _Available since v4.3._
     */
    function tryRecover(bytes32 hash, bytes memory signature) internal pure returns (address, RecoverError) {
        if (signature.length == 65) {
            bytes32 r;
            bytes32 s;
            uint8 v;
            // ecrecover takes the signature parameters, and the only way to get them
            // currently is to use assembly.
            /// @solidity memory-safe-assembly
            assembly {
                r := mload(add(signature, 0x20))
                s := mload(add(signature, 0x40))
                v := byte(0, mload(add(signature, 0x60)))
            }
            return tryRecover(hash, v, r, s);
        } else {
            return (address(0), RecoverError.InvalidSignatureLength);
        }
    }

    /**
     * @dev Returns the address that signed a hashed message (`hash`) with
     * `signature`. This address can then be used for verification purposes.
     *
     * The `ecrecover` EVM opcode allows for malleable (non-unique) signatures:
     * this function rejects them by requiring the `s` value to be in the lower
     * half order, and the `v` value to be either 27 or 28.
     *
     * IMPORTANT: `hash` _must_ be the result of a hash operation for the
     * verification to be secure: it is possible to craft signatures that
     * recover to arbitrary addresses for non-hashed data. A safe way to ensure
     * this is by receiving a hash of the original message (which may otherwise
     * be too long), and then calling {toEthSignedMessageHash} on it.
     */
    function recover(bytes32 hash, bytes memory signature) internal pure returns (address) {
        (address recovered, RecoverError error) = tryRecover(hash, signature);
        _throwError(error);
        return recovered;
    }

    /**
     * @dev Overload of {ECDSA-tryRecover} that receives the `r` and `vs` short-signature fields separately.
     *
     * See https://eips.ethereum.org/EIPS/eip-2098[EIP-2098 short signatures]
     *
     * _Available since v4.3._
     */
    function tryRecover(
        bytes32 hash,
        bytes32 r,
        bytes32 vs
    ) internal pure returns (address, RecoverError) {
        bytes32 s = vs & bytes32(0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff);
        uint8 v = uint8((uint256(vs) >> 255) + 27);
        return tryRecover(hash, v, r, s);
    }

    /**
     * @dev Overload of {ECDSA-recover} that receives the `r and `vs` short-signature fields separately.
     *
     * _Available since v4.2._
     */
    function recover(
        bytes32 hash,
        bytes32 r,
        bytes32 vs
    ) internal pure returns (address) {
        (address recovered, RecoverError error) = tryRecover(hash, r, vs);
        _throwError(error);
        return recovered;
    }

    /**
     * @dev Overload of {ECDSA-tryRecover} that receives the `v`,
     * `r` and `s` signature fields separately.
     *
     * _Available since v4.3._
     */
    function tryRecover(
        bytes32 hash,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal pure returns (address, RecoverError) {
        // EIP-2 still allows signature malleability for ecrecover(). Remove this possibility and make the signature
        // unique. Appendix F in the Ethereum Yellow paper (https://ethereum.github.io/yellowpaper/paper.pdf), defines
        // the valid range for s in (301): 0 < s < secp256k1n ÷ 2 + 1, and for v in (302): v ∈ {27, 28}. Most
        // signatures from current libraries generate a unique signature with an s-value in the lower half order.
        //
        // If your library generates malleable signatures, such as s-values in the upper range, calculate a new s-value
        // with 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141 - s1 and flip v from 27 to 28 or
        // vice versa. If your library also generates signatures with 0/1 for v instead 27/28, add 27 to v to accept
        // these malleable signatures as well.
        if (uint256(s) > 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0) {
            return (address(0), RecoverError.InvalidSignatureS);
        }

        // If the signature is valid (and not malleable), return the signer address
        address signer = ecrecover(hash, v, r, s);
        if (signer == address(0)) {
            return (address(0), RecoverError.InvalidSignature);
        }

        return (signer, RecoverError.NoError);
    }

    /**
     * @dev Overload of {ECDSA-recover} that receives the `v`,
     * `r` and `s` signature fields separately.
     */
    function recover(
        bytes32 hash,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) internal pure returns (address) {
        (address recovered, RecoverError error) = tryRecover(hash, v, r, s);
        _throwError(error);
        return recovered;
    }

    /**
     * @dev Returns an Ethereum Signed Message, created from a `hash`. This
     * produces hash corresponding to the one signed with the
     * https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]
     * JSON-RPC method as part of EIP-191.
     *
     * See {recover}.
     */
    function toEthSignedMessageHash(bytes32 hash) internal pure returns (bytes32) {
        // 32 is the length in bytes of hash,
        // enforced by the type signature above
        return keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", hash));
    }

    /**
     * @dev Returns an Ethereum Signed Message, created from `s`. This
     * produces hash corresponding to the one signed with the
     * https://eth.wiki/json-rpc/API#eth_sign[`eth_sign`]
     * JSON-RPC method as part of EIP-191.
     *
     * See {recover}.
     */
    function toEthSignedMessageHash(bytes memory s) internal pure returns (bytes32) {
        return keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n", Strings.toString(s.length), s));
    }

    /**
     * @dev Returns an Ethereum Signed Typed Data, created from a
     * `domainSeparator` and a `structHash`. This produces hash corresponding
     * to the one signed with the
     * https://eips.ethereum.org/EIPS/eip-712[`eth_signTypedData`]
     * JSON-RPC method as part of EIP-712.
     *
     * See {recover}.
     */
    function toTypedDataHash(bytes32 domainSeparator, bytes32 structHash) internal pure returns (bytes32) {
        return keccak256(abi.encodePacked("\x19\x01", domainSeparator, structHash));
    }
}

// File: lib/openzeppelin-contracts/contracts/utils/math/Math.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (utils/math/Math.sol)

pragma solidity ^0.8.0;

/**
 * @dev Standard math utilities missing in the Solidity language.
 */
library Math {
    enum Rounding {
        Down, // Toward negative infinity
        Up, // Toward infinity
        Zero // Toward zero
    }

    /**
     * @dev Returns the largest of two numbers.
     */
    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a > b ? a : b;
    }

    /**
     * @dev Returns the smallest of two numbers.
     */
    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }

    /**
     * @dev Returns the average of two numbers. The result is rounded towards
     * zero.
     */
    function average(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b) / 2 can overflow.
        return (a & b) + (a ^ b) / 2;
    }

    /**
     * @dev Returns the ceiling of the division of two numbers.
     *
     * This differs from standard division with `/` in that it rounds up instead
     * of rounding down.
     */
    function ceilDiv(uint256 a, uint256 b) internal pure returns (uint256) {
        // (a + b - 1) / b can overflow on addition, so we distribute.
        return a == 0 ? 0 : (a - 1) / b + 1;
    }

    /**
     * @notice Calculates floor(x * y / denominator) with full precision. Throws if result overflows a uint256 or denominator == 0
     * @dev Original credit to Remco Bloemen under MIT license (https://xn--2-umb.com/21/muldiv)
     * with further edits by Uniswap Labs also under MIT license.
     */
    function mulDiv(
        uint256 x,
        uint256 y,
        uint256 denominator
    ) internal pure returns (uint256 result) {
        unchecked {
            // 512-bit multiply [prod1 prod0] = x * y. Compute the product mod 2^256 and mod 2^256 - 1, then use
            // use the Chinese Remainder Theorem to reconstruct the 512 bit result. The result is stored in two 256
            // variables such that product = prod1 * 2^256 + prod0.
            uint256 prod0; // Least significant 256 bits of the product
            uint256 prod1; // Most significant 256 bits of the product
            assembly {
                let mm := mulmod(x, y, not(0))
                prod0 := mul(x, y)
                prod1 := sub(sub(mm, prod0), lt(mm, prod0))
            }

            // Handle non-overflow cases, 256 by 256 division.
            if (prod1 == 0) {
                return prod0 / denominator;
            }

            // Make sure the result is less than 2^256. Also prevents denominator == 0.
            require(denominator > prod1);

            ///////////////////////////////////////////////
            // 512 by 256 division.
            ///////////////////////////////////////////////

            // Make division exact by subtracting the remainder from [prod1 prod0].
            uint256 remainder;
            assembly {
                // Compute remainder using mulmod.
                remainder := mulmod(x, y, denominator)

                // Subtract 256 bit number from 512 bit number.
                prod1 := sub(prod1, gt(remainder, prod0))
                prod0 := sub(prod0, remainder)
            }

            // Factor powers of two out of denominator and compute largest power of two divisor of denominator. Always >= 1.
            // See https://cs.stackexchange.com/q/138556/92363.

            // Does not overflow because the denominator cannot be zero at this stage in the function.
            uint256 twos = denominator & (~denominator + 1);
            assembly {
                // Divide denominator by twos.
                denominator := div(denominator, twos)

                // Divide [prod1 prod0] by twos.
                prod0 := div(prod0, twos)

                // Flip twos such that it is 2^256 / twos. If twos is zero, then it becomes one.
                twos := add(div(sub(0, twos), twos), 1)
            }

            // Shift in bits from prod1 into prod0.
            prod0 |= prod1 * twos;

            // Invert denominator mod 2^256. Now that denominator is an odd number, it has an inverse modulo 2^256 such
            // that denominator * inv = 1 mod 2^256. Compute the inverse by starting with a seed that is correct for
            // four bits. That is, denominator * inv = 1 mod 2^4.
            uint256 inverse = (3 * denominator) ^ 2;

            // Use the Newton-Raphson iteration to improve the precision. Thanks to Hensel's lifting lemma, this also works
            // in modular arithmetic, doubling the correct bits in each step.
            inverse *= 2 - denominator * inverse; // inverse mod 2^8
            inverse *= 2 - denominator * inverse; // inverse mod 2^16
            inverse *= 2 - denominator * inverse; // inverse mod 2^32
            inverse *= 2 - denominator * inverse; // inverse mod 2^64
            inverse *= 2 - denominator * inverse; // inverse mod 2^128
            inverse *= 2 - denominator * inverse; // inverse mod 2^256

            // Because the division is now exact we can divide by multiplying with the modular inverse of denominator.
            // This will give us the correct result modulo 2^256. Since the preconditions guarantee that the outcome is
            // less than 2^256, this is the final result. We don't need to compute the high bits of the result and prod1
            // is no longer required.
            result = prod0 * inverse;
            return result;
        }
    }

    /**
     * @notice Calculates x * y / denominator with full precision, following the selected rounding direction.
     */
    function mulDiv(
        uint256 x,
        uint256 y,
        uint256 denominator,
        Rounding rounding
    ) internal pure returns (uint256) {
        uint256 result = mulDiv(x, y, denominator);
        if (rounding == Rounding.Up && mulmod(x, y, denominator) > 0) {
            result += 1;
        }
        return result;
    }

    /**
     * @dev Returns the square root of a number. If the number is not a perfect square, the value is rounded down.
     *
     * Inspired by Henry S. Warren, Jr.'s "Hacker's Delight" (Chapter 11).
     */
    function sqrt(uint256 a) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }

        // For our first guess, we get the biggest power of 2 which is smaller than the square root of the target.
        //
        // We know that the "msb" (most significant bit) of our target number `a` is a power of 2 such that we have
        // `msb(a) <= a < 2*msb(a)`. This value can be written `msb(a)=2**k` with `k=log2(a)`.
        //
        // This can be rewritten `2**log2(a) <= a < 2**(log2(a) + 1)`
        // → `sqrt(2**k) <= sqrt(a) < sqrt(2**(k+1))`
        // → `2**(k/2) <= sqrt(a) < 2**((k+1)/2) <= 2**(k/2 + 1)`
        //
        // Consequently, `2**(log2(a) / 2)` is a good first approximation of `sqrt(a)` with at least 1 correct bit.
        uint256 result = 1 << (log2(a) >> 1);

        // At this point `result` is an estimation with one bit of precision. We know the true value is a uint128,
        // since it is the square root of a uint256. Newton's method converges quadratically (precision doubles at
        // every iteration). We thus need at most 7 iteration to turn our partial result with one bit of precision
        // into the expected uint128 result.
        unchecked {
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            result = (result + a / result) >> 1;
            return min(result, a / result);
        }
    }

    /**
     * @notice Calculates sqrt(a), following the selected rounding direction.
     */
    function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = sqrt(a);
            return result + (rounding == Rounding.Up && result * result < a ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 2, rounded down, of a positive value.
     * Returns 0 if given 0.
     */
    function log2(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >> 128 > 0) {
                value >>= 128;
                result += 128;
            }
            if (value >> 64 > 0) {
                value >>= 64;
                result += 64;
            }
            if (value >> 32 > 0) {
                value >>= 32;
                result += 32;
            }
            if (value >> 16 > 0) {
                value >>= 16;
                result += 16;
            }
            if (value >> 8 > 0) {
                value >>= 8;
                result += 8;
            }
            if (value >> 4 > 0) {
                value >>= 4;
                result += 4;
            }
            if (value >> 2 > 0) {
                value >>= 2;
                result += 2;
            }
            if (value >> 1 > 0) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 2, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log2(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log2(value);
            return result + (rounding == Rounding.Up && 1 << result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 10, rounded down, of a positive value.
     * Returns 0 if given 0.
     */
    function log10(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >= 10**64) {
                value /= 10**64;
                result += 64;
            }
            if (value >= 10**32) {
                value /= 10**32;
                result += 32;
            }
            if (value >= 10**16) {
                value /= 10**16;
                result += 16;
            }
            if (value >= 10**8) {
                value /= 10**8;
                result += 8;
            }
            if (value >= 10**4) {
                value /= 10**4;
                result += 4;
            }
            if (value >= 10**2) {
                value /= 10**2;
                result += 2;
            }
            if (value >= 10**1) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 10, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log10(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log10(value);
            return result + (rounding == Rounding.Up && 10**result < value ? 1 : 0);
        }
    }

    /**
     * @dev Return the log in base 256, rounded down, of a positive value.
     * Returns 0 if given 0.
     *
     * Adding one to the result gives the number of pairs of hex symbols needed to represent `value` as a hex string.
     */
    function log256(uint256 value) internal pure returns (uint256) {
        uint256 result = 0;
        unchecked {
            if (value >> 128 > 0) {
                value >>= 128;
                result += 16;
            }
            if (value >> 64 > 0) {
                value >>= 64;
                result += 8;
            }
            if (value >> 32 > 0) {
                value >>= 32;
                result += 4;
            }
            if (value >> 16 > 0) {
                value >>= 16;
                result += 2;
            }
            if (value >> 8 > 0) {
                result += 1;
            }
        }
        return result;
    }

    /**
     * @dev Return the log in base 10, following the selected rounding direction, of a positive value.
     * Returns 0 if given 0.
     */
    function log256(uint256 value, Rounding rounding) internal pure returns (uint256) {
        unchecked {
            uint256 result = log256(value);
            return result + (rounding == Rounding.Up && 1 << (result * 8) < value ? 1 : 0);
        }
    }
}

// File: lib/openzeppelin-contracts/contracts/utils/Strings.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (utils/Strings.sol)

pragma solidity ^0.8.0;

import "./math/Math.sol";

/**
 * @dev String operations.
 */
library Strings {
    bytes16 private constant _SYMBOLS = "0123456789abcdef";
    uint8 private constant _ADDRESS_LENGTH = 20;

    /**
     * @dev Converts a `uint256` to its ASCII `string` decimal representation.
     */
    function toString(uint256 value) internal pure returns (string memory) {
        unchecked {
            uint256 length = Math.log10(value) + 1;
            string memory buffer = new string(length);
            uint256 ptr;
            /// @solidity memory-safe-assembly
            assembly {
                ptr := add(buffer, add(32, length))
            }
            while (true) {
                ptr--;
                /// @solidity memory-safe-assembly
                assembly {
                    mstore8(ptr, byte(mod(value, 10), _SYMBOLS))
                }
                value /= 10;
                if (value == 0) break;
            }
            return buffer;
        }
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation.
     */
    function toHexString(uint256 value) internal pure returns (string memory) {
        unchecked {
            return toHexString(value, Math.log256(value) + 1);
        }
    }

    /**
     * @dev Converts a `uint256` to its ASCII `string` hexadecimal representation with fixed length.
     */
    function toHexString(uint256 value, uint256 length) internal pure returns (string memory) {
        bytes memory buffer = new bytes(2 * length + 2);
        buffer[0] = "0";
        buffer[1] = "x";
        for (uint256 i = 2 * length + 1; i > 1; --i) {
            buffer[i] = _SYMBOLS[value & 0xf];
            value >>= 4;
        }
        require(value == 0, "Strings: hex length insufficient");
        return string(buffer);
    }

    /**
     * @dev Converts an `address` with fixed length of 20 bytes to its not checksummed ASCII `string` hexadecimal representation.
     */
    function toHexString(address addr) internal pure returns (string memory) {
        return toHexString(uint256(uint160(addr)), _ADDRESS_LENGTH);
    }
}

// File: src/HelloBridge.sol



// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.19;

import {IERC20} from "lib/openzeppelin-contracts/contracts/token/ERC20/IERC20.sol";
import {ECDSA} from "lib/openzeppelin-contracts/contracts/utils/cryptography/ECDSA.sol";
import {Ownable} from "lib/openzeppelin-contracts/contracts/access/Ownable.sol";
import {HelloBridgeStore} from "./HelloBridgeStore.sol";
/* -------------------------------------------------------------------------- */
/*                                   errors                                   */
/* -------------------------------------------------------------------------- */
error SignerNotWithdrawSigner();
error NoAmountToWithdraw();
error CannotBridgeToUnsupportedChain();
error Paused();
error NotPaused();
error ZeroAddress();

///@notice The owner will always be a multisig wallet.


/* -------------------------------------------------------------------------- */
/*                                 HelloBridge                                */
/* -------------------------------------------------------------------------- */
/**
 * @title A cross-chain bridge for HelloToken
 * @author 0xSimon
 * @notice It is recommended to use the provided UI to bridge your tokens from chain A to chain B
 * @dev Assumptions:
 *     - On chains that this contract is deployed to (besides the mainnet), the entire supply of HelloToken will be minted and sent to this contract.
 */
contract HelloBridge is Ownable {
    using ECDSA for bytes32;

    /* -------------------------------------------------------------------------- */
    /*                                   events                                   */
    /* -------------------------------------------------------------------------- */
    event Deposit(address indexed sender, uint256 amount, uint256 chainId);
    event Claim(address indexed sender, uint256 totalDepositedOnOtherChain, uint256 otherChainId);
    event SupportedChainChanged(uint256 chainID, bool isSupported);
    event SupportedChainsChanged(uint256[] chainIDs, bool isSupported);
    event WithdrawSigner1Changed(address signer);
    event WithdrawSigner2Changed(address signer);
    event PausedChanged(bool depositPaused, bool claimPaused);
    event BridgeStoreChanged(address store);

    /* -------------------------------------------------------------------------- */
    /*                                  constants                                 */
    /* -------------------------------------------------------------------------- */
    /**
     * @notice The HelloToken contract
     */
    IERC20 public immutable HELLO_TOKEN;

    /* -------------------------------------------------------------------------- */
    /*                                   states                                   */
    /* -------------------------------------------------------------------------- */
    /**
     * @notice The signer providing signatures for claiming tokens on the destination chain
     */
    address public withdrawSigner1;
    address public withdrawSigner2;

    /**
     * @notice Storage contract for deposits and withdrawals numbers
     */
    HelloBridgeStore public store;

    /**
     * @notice A mapping to store which destination chains are supported
     */
    mapping(uint256 => bool) public supportedChains;

    bool public depositPaused;
    bool public claimPaused;

    /**
     * @notice Deploys the contract and saves the HelloToken contract address
     *  @dev `msg.sender` is assigned to the owner, pay attention if this contract is deployed via another contract
     *  @param _helloToken The address of HelloToken
     */
    constructor(address _helloToken) {
        HELLO_TOKEN = IERC20(_helloToken);
    }

    /* -------------------------------------------------------------------------- */
    /*                                  external                                  */
    /* -------------------------------------------------------------------------- */
    /**
     * @notice Bridge HelloToken to another chain. HelloToken will be transferred to this contract.
     * @notice Ensure approvals for HelloToken has been set and the destination chain is supported.
     * @param amount Amount of HelloToken to bridge to another chain
     * @param chainId The chain ID of the destination chain
     * @dev Reverts if the destination chain is not supported
     */
    function sendToChain(uint256 amount, uint256 chainId) external {
        if (depositPaused) _revert(Paused.selector);

        // check chain
        if (!supportedChains[chainId]) _revert(CannotBridgeToUnsupportedChain.selector);

        // update state
        uint256 _currentDepsosit = store.totalCrossChainDeposits(msg.sender, chainId);
        store.setTotalCrossChainDeposits(msg.sender, chainId, _currentDepsosit + amount);

        // transfer tokens
        HELLO_TOKEN.transferFrom(msg.sender, address(this), amount);

        emit Deposit(msg.sender, amount, chainId);
    }

    /**
     * @notice Claims tokens deposited in the source chain. A signature is required.
     * @notice HelloToken will be transferred from this account to the caller.
     * @param totalDepositedOnOtherChain The total amount you have deposited in the source chain
     * @param otherChainId The chain ID of the source chain
     * @param signature The signature signed by `withdrawSigner`
     * @dev Reverts if there's no amount to claim.
     * @dev Reverts if the signature is invalid
     * @dev Assumptions:
     *     - `otherChainId` is supported, a user would not have been able to deposit if the path from `otherChainId` to this chain is not supported
     *     - `totalDepositedOnOtherChain` is checked on chain with ID `otherChainId` before a signature is generated for this transaction
     */
    function claimFromChain(
        uint256 totalDepositedOnOtherChain,
        uint256 otherChainId,
        bytes memory signature,
        bytes memory signature2
    ) external {
        if (claimPaused) _revert(Paused.selector);

        // note: this can never undeflow as the user would not have been able to withdraw if they had no balance
        uint256 amountToWithdraw =
            totalDepositedOnOtherChain - store.totalCrossChainWithdrawals(msg.sender, otherChainId);

        // check amount
        if (amountToWithdraw == 0) _revert(NoAmountToWithdraw.selector);

        // check signature
        bytes32 hash = keccak256(
            abi.encodePacked(msg.sender, totalDepositedOnOtherChain, otherChainId, block.chainid, address(this))
        );

        if (hash.toEthSignedMessageHash().recover(signature) != withdrawSigner1) {
            _revert(SignerNotWithdrawSigner.selector);
        }

        if (hash.toEthSignedMessageHash().recover(signature2) != withdrawSigner2) {
            _revert(SignerNotWithdrawSigner.selector);
        }

        // update state
        store.setTotalCrossChainWithdrawals(msg.sender, otherChainId, totalDepositedOnOtherChain);

        // transfer tokens
        HELLO_TOKEN.transfer(msg.sender, amountToWithdraw);

        emit Claim(msg.sender, totalDepositedOnOtherChain, otherChainId);
    }

    /* -------------------------------------------------------------------------- */
    /*                                   owners                                   */
    /* -------------------------------------------------------------------------- */
    /**
     * @notice Owner only - Updates the address of the withdrawal signer
     * @param _withdrawSigner Address of the withdrawal signer
     */
    function setWithdrawSigner(address _withdrawSigner) external onlyOwner {
        // check
        if (_withdrawSigner == address(0)) {
            _revert(ZeroAddress.selector);
        }

        // set
        withdrawSigner1 = _withdrawSigner;

        // emit
        emit WithdrawSigner1Changed(_withdrawSigner);
    }

    function setWithdrawSigner2(address _withdrawSigner2) external onlyOwner {
        // check
        if (_withdrawSigner2 == address(0)) {
            _revert(ZeroAddress.selector);
        }

        // set
        withdrawSigner2 = _withdrawSigner2;

        // emit
        emit WithdrawSigner2Changed(_withdrawSigner2);
    }

    /**
     * @notice Owner only - Updates a supported destination chain
     * @param chainId Chain ID of a destination chain
     * @param isSupported Whether the destination chain is supported
     */
    function setSupportedChain(uint256 chainId, bool isSupported) external onlyOwner {
        _setSupportedChain(chainId, isSupported);

        emit SupportedChainChanged(chainId, isSupported);
    }

    /**
     * @notice Owner only - Batch update supported destination chains
     * @param chainIds Chain IDs of the destination chains
     * @param isSupported Whether the destination chains are supported
     */
    function setSupportedChains(uint256[] calldata chainIds, bool isSupported) external onlyOwner {
        for (uint256 i; i < chainIds.length;) {
            _setSupportedChain(chainIds[i], isSupported);
            unchecked {
                ++i;
            }
        }

        emit SupportedChainsChanged(chainIds, isSupported);
    }

    /**
     * @notice Pause / unpause deposit & claim
     * @param depositPaused_ Whether to pause deposit
     * @param depositPaused_ Whether to pause claim
     */
    function setPaused(bool depositPaused_, bool claimPaused_) external onlyOwner {
        depositPaused = depositPaused_;
        claimPaused = claimPaused_;

        emit PausedChanged(depositPaused_, claimPaused_);
    }

    function setBridgeStore(address a_) external onlyOwner {
        // check
        if (a_ == address(0)) {
            _revert(ZeroAddress.selector);
        }

        // set
        store = HelloBridgeStore(a_);

        // emit
        emit BridgeStoreChanged(a_);
    }

    /**
     * @notice Migrates the bridge contract to another. Tokens in this contract will be transferred to the new contract.
     * @dev The new bridge contract should use the data stored in `store`.
     * @param bridgeAddress Address of the new contract
     */
    function migrateBridge(address bridgeAddress) external onlyOwner {
        // check zero
        if (bridgeAddress == address(0)) {
            _revert(ZeroAddress.selector);
        }

        // check paused
        if (!depositPaused || !claimPaused) {
            _revert(NotPaused.selector);
        }

        HELLO_TOKEN.transfer(bridgeAddress, HELLO_TOKEN.balanceOf(address(this)));
    }

    /* -------------------------------------------------------------------------- */
    /*                                  internal                                  */
    /* -------------------------------------------------------------------------- */
    function _setSupportedChain(uint256 chainId, bool isSupported) internal {
        supportedChains[chainId] = isSupported;
    }

    function _revert(bytes4 selector) internal pure {
        assembly {
            mstore(0x0, selector)
            revert(0x0, 0x04)
        }
    }
}

// File: src/HelloBridgeStore.sol



// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.19;

import {Ownable} from "lib/openzeppelin-contracts/contracts/access/Ownable.sol";


///@notice The contract is a storage contract for the bridge contract.
///@notice The owner will always be a multisig wallet.

/* -------------------------------------------------------------------------- */
/*                                   errors                                   */
/* -------------------------------------------------------------------------- */
error SignerNotWithdrawSigner();
error NoAmountToWithdraw();
error CannotBridgeToUnsupportedChain();
error Paused();
error NotPaused();
error ZeroAddress();

contract HelloBridgeStore is Ownable {
    /* -------------------------------------------------------------------------- */
    /*                                   errors                                   */
    /* -------------------------------------------------------------------------- */
    error ErrUnauthorized();
    error ErrZeroAddress();

    /* -------------------------------------------------------------------------- */
    /*                                   events                                   */
    /* -------------------------------------------------------------------------- */
    event BridgeContractChanged(address bridgeContract);

    /* -------------------------------------------------------------------------- */
    /*                                   states                                   */
    /* -------------------------------------------------------------------------- */
    /**
     * @notice A mapping that stores how much HelloToken a user has deposited to bridge to a destination chain
     * @dev Maps from userAddress -> chainID -> amount
     */
    mapping(address => mapping(uint256 => uint256)) public totalCrossChainDeposits;

    /**
     * @notice A mapping that stores how much HelloToken a user has withdrawn from a destination chain
     * @dev Maps from userAddress -> chainID -> amount
     */
    mapping(address => mapping(uint256 => uint256)) public totalCrossChainWithdrawals;

    /**
     * @notice The bridge contract associated with this storage contract.
     * This is the only contract authorized to update `totalCrossChainDeposits` & `totalCrossChainWithdrawals`
     */
    address public bridgeContract;

    /* -------------------------------------------------------------------------- */
    /*                                    owner                                   */
    /* -------------------------------------------------------------------------- */
    /**
     * @notice Updates the bridge contract associated with this storage contract
     */
    function setBridgeContract(address b_) external onlyOwner {
        if (b_ == address(0)) {
            revert ErrZeroAddress();
        }

        bridgeContract = b_;

        emit BridgeContractChanged(b_);
    }

    /* -------------------------------------------------------------------------- */
    /*                                  external                                  */
    /* -------------------------------------------------------------------------- */
    /**
     * @notice Updates totalCrossChainDeposits of a user to a destination chain
     * @param address_ The address to update
     * @param chainID_ The destination chainID of the deposit
     * @param amount_ The amount of token deposited
     */
    function setTotalCrossChainDeposits(address address_, uint256 chainID_, uint256 amount_) external {
        if (msg.sender != bridgeContract) {
            revert ErrUnauthorized();
        }

        totalCrossChainDeposits[address_][chainID_] = amount_;
    }

    /**
     * @notice Updates totalCrossChainWithdrawals of a user from a source chain
     * @param address_ The address to update
     * @param chainID_ The source chainID of the withdrawal
     * @param amount_ The amount of token withdrawn
     */
    function setTotalCrossChainWithdrawals(address address_, uint256 chainID_, uint256 amount_) external {
        if (msg.sender != bridgeContract) {
            revert ErrUnauthorized();
        }

        totalCrossChainWithdrawals[address_][chainID_] = amount_;
    }
}
// File: src/HelloToken.sol



// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.19;

import "lib/openzeppelin-contracts-upgradeable/contracts/access/OwnableUpgradeable.sol";
import "lib/openzeppelin-contracts-upgradeable/contracts/token/ERC20/ERC20Upgradeable.sol";
import "lib/openzeppelin-contracts-upgradeable/contracts/proxy/utils/Initializable.sol";
import {IERC20} from "lib/openzeppelin-contracts/contracts/token/ERC20/IERC20.sol";

///@notice The owner will always be a multisig wallet.

/* -------------------------------------------------------------------------- */
/*                                   errors                                   */
/* -------------------------------------------------------------------------- */
error Blacklisted();
error ZeroAddress();

/* -------------------------------------------------------------------------- */
/*                                 HelloToken                                 */
/* -------------------------------------------------------------------------- */
/**
 * @title Contract for the ERC20 HelloToken on chains other than the mainnet (the chain with main dex LP)
 * @notice The full supply of tokens are minted to the deployer on deploy, and should be transferred to the bridge on this chain.
 * @notice Assumptions:
 *  - The bridge contract is the only entry point for bridged tokens from other chains
 *  - Tokens getting bridge to the chain for which this contract resides in must first be deposited in the
 *    bridge contract on the source chain
 * @author 0xSimon
 */
contract Hello is Initializable, ERC20Upgradeable, OwnableUpgradeable {
    /* -------------------------------------------------------------------------- */
    /*                                   events                                   */
    /* -------------------------------------------------------------------------- */
    event BlacklistedChanged(address wallet, bool status);
    event OnRescueToken(address tokenAddress, uint256 tokens);
    event OnClearStuckBalance(uint256 amountPercentage, address adr);

    /* -------------------------------------------------------------------------- */
    /*                                   states                                   */
    /* -------------------------------------------------------------------------- */
    /**
     * @notice A mapping that stores blacklisted addresses
     */
    mapping(address => bool) public blacklisted;

    /* -------------------------------------------------------------------------- */
    /*                                 constructor                                */
    /* -------------------------------------------------------------------------- */
    /**
     * @notice Deploys the contract and mints the entire supply to the deployer
     * @dev `tx.origin` is used instead of `msg.sender` just in case this contract get deployed via a contract
     *  @custom:oz-upgrades-unsafe-allow constructor

     */
    constructor() {
        _disableInitializers();
    }

    function initialize() public initializer {
        __ERC20_init("Hello", "HELLO");
        __Ownable_init();
        _mint(tx.origin, 1e9 ether);
    }

    /* -------------------------------------------------------------------------- */
    /*                                  overrides                                 */
    /* -------------------------------------------------------------------------- */
    /**
     * @dev Override the _transfer function to support blacklisting
     */
    function _transfer(address sender, address to, uint256 amount) internal override {
        if (blacklisted[sender] || blacklisted[to]) {
            revert Blacklisted();
        }

        super._transfer(sender, to, amount);
    }

    /* -------------------------------------------------------------------------- */
    /*                                   owners                                   */
    /* -------------------------------------------------------------------------- */
    /**
     * @notice Owner only - Updates the blacklist mapping
     * @param _wallet the address to update the blacklist status of
     * @param status whether the address is blacklisted
     */
    function setBlacklisted(address _wallet, bool status) external onlyOwner {
        // check zero
        if (_wallet == address(0)) {
            revert ZeroAddress();
        }

        // update
        blacklisted[_wallet] = status;

        // emit
        emit BlacklistedChanged(_wallet, status);
    }

    function rescueToken(address tokenAddress, uint256 tokens) external onlyOwner {
        IERC20(tokenAddress).transfer(msg.sender, tokens);
        emit OnRescueToken(tokenAddress, tokens);
    }

    function clearStuckBalance(address adr) external onlyOwner {
        if (adr == address(0)) revert ZeroAddress();
        uint256 __balance = address(this).balance;
        (bool success,) = payable(adr).call{value: __balance}("");
        require(success);
        emit OnClearStuckBalance(__balance, adr);
    }
}

// File: src/KillerWhalesS1.sol



// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.19;

import "lib/openzeppelin-contracts/contracts/access/Ownable.sol";
import "lib/openzeppelin-contracts/contracts/utils/cryptography/ECDSA.sol";
import {IERC20} from "lib/openzeppelin-contracts/contracts/token/ERC20/IERC20.sol";

///@notice The owner will always be a multisig wallet.


/* -------------------------------------------------------------------------- */
/*                                   errors                                   */
/* -------------------------------------------------------------------------- */
error InsufficientEth();
error EpisodeDoesNotExist();
error EpisodeAlreadyPurchased();
error NotOwnerOrAdmin();
error SignerCannotBeZeroAddress();
error InvalidSignature();
error VoucherExpired();
error CannotPurchaseWithoutSignerApproval();

/* -------------------------------------------------------------------------- */
/*                               KillerWhalesS1                               */
/* -------------------------------------------------------------------------- */
/**
 * @title Contract for purchasing episodes for Season 1 of KillerWhales using HelloToken
 * @author 0xSimon
 */
contract KillerWhalesS1 is Ownable {
    using ECDSA for bytes32;

    /* -------------------------------------------------------------------------- */
    /*                                   events                                   */
    /* -------------------------------------------------------------------------- */
    /**
     * @notice emits when an episode is purchased by a user
     */
    event EpisodesPurchased(address indexed user, uint256[] episode);
    event SeasonPassPurchased(address indexed user);
    event SignerChanged(address signer);
    event SignerOnlyChanged(bool signerOnly);
    event PricePerEpisodeChanged(uint256 pricePerEpisode);

    /* -------------------------------------------------------------------------- */
    /*                                   statse                                   */
    /* -------------------------------------------------------------------------- */
    /**
     * @dev The max episodeID (i.e. available episodes 0, 1, ..., 4)
     */
    uint256 private constant MAX_EPISODE_ID = 4;

    /**
     * @notice The Bitpos if a user owns the season pass
     */
    uint256 private constant OWNS_SEASON_PASS_BITPOS = (1 << 255);

    /**
     * @notice The HelloToken contract
     */
    IERC20 public immutable HELLO_TOKEN;

    /**
     * @notice The price per episode
     */

    uint256 public pricePerEpisode = 1 ether;

    /**
     * @notice The signer providing signatures for discounts on episodes
     */
    address public signer;

    /**
     * @notice if true, episodes can only be purchased through signatures
     */
    bool public signerOnly;

    /**
     * @notice A mapping that stores purchased episodes for every user
     * @dev Maps between an address to a bitmap that contains purchased episodes
     * @dev Assumptions:
     *     - There are only 5 episodes in Season 1 therefore the bitmap can never overflow
     * Examples:
     *     - If a user has purchased episode 0, the bitmap would look like:
     *                          00000001
     *     - If a user has purchased episodes 1 & 3, the bitmap would look like:
     *                          00001010
     */
    mapping(address => uint256) public episodePurchasedBitmap;

    /* -------------------------------------------------------------------------- */
    /*                                 constructor                                */
    /* -------------------------------------------------------------------------- */
    /**
     * @notice Deploys the contract and saves the HelloToken contract address and the signer
     * @dev `msg.sender` is assigned to the owner, pay attention if this contract is deployed via another contract
     * @param _helloToken The address of HelloToken
     * @param _signer Address of the discount signer
     */
    constructor(address _helloToken, address _signer) {
        HELLO_TOKEN = IERC20(_helloToken);
        if (_signer == address(0)) {
            _revert(SignerCannotBeZeroAddress.selector);
        }
        signer = _signer;
    }

    /* -------------------------------------------------------------------------- */
    /*                                  external                                  */
    /* -------------------------------------------------------------------------- */
    /**
     * @notice Purchase episodes without discount
     * @notice HelloTokens will be transferred to this contract
     * @notice Ensure approvals for HelloToken has been set
     * @param episodeIds the episodeIDs to be purchased
     * @dev Reverts if the any of the episodes in the argument has been purchased already
     * @dev Reverts if the any of the episodes in the argument does not exist (i.e. > MAX_EPISODE_ID)
     */
    function purchaseEpisodesNoDiscount(uint256[] calldata episodeIds) external {
        if (signerOnly) {
            _revert(CannotPurchaseWithoutSignerApproval.selector);
        }

        // calculate total price
        uint256 __totalPrice = episodeIds.length * pricePerEpisode;

        // update state
        _grantEpisodes(msg.sender, episodeIds);

        // transfer tokens
        HELLO_TOKEN.transferFrom(msg.sender, address(this), __totalPrice);
    }

    /**
     * @notice Purchase espidoes with discount
     * @notice HelloTokens will be transferred to this contract
     * @notice Ensure approvals for HelloToken has been set
     * @param episodeIds the episodeIDs to be purchased
     * @param _discount the discount to be applied in basisPoint (e.g. 500 for 5% discount)
     * @param _expirationTimestamp the expiration timestamp for which this discount can be applied
     * @param signature the signature signed by `signer`
     */
    function purchaseEpisodeWithDiscount(
        uint256[] calldata episodeIds,
        uint256 _discount,
        uint256 _expirationTimestamp,
        bytes calldata signature
    ) external {
        if (signerOnly) {
            _revert(CannotPurchaseWithoutSignerApproval.selector);
        }

        // check signature
        _checkDiscountSignature(episodeIds, _discount, _expirationTimestamp, signature);

        // calculate total price - discount
        uint256 __totalPrice = episodeIds.length * pricePerEpisode * (10_000 - _discount) / 10_000;

        // update state
        _grantEpisodes(msg.sender, episodeIds);

        // transfer tokens
        HELLO_TOKEN.transferFrom(msg.sender, address(this), __totalPrice);
    }

    /// @notice Purchase episodes with a total price and signature
    /// @notice HelloTokens will be transferred to this contract
    /// @notice grant episodes to the user
    /// @param episodeIds the episodeIDs to be purchased
    /// @param totalPrice the total price of the episodes
    /// @param _expirationTimestamp the expiration timestamp for which this price is applied
    /// @param signature the signature signed by `signer`
    function purchaseEpisodesSignatureOnly(
        uint256[] calldata episodeIds,
        uint256 totalPrice,
        uint256 _expirationTimestamp,
        bytes calldata signature
    ) external {
        // check signature
        _checkTotalPriceSignature(episodeIds, totalPrice, _expirationTimestamp, signature);

        // update state
        _grantEpisodes(msg.sender, episodeIds);

        // transfer tokens
        HELLO_TOKEN.transferFrom(msg.sender, address(this), totalPrice);
    }

    /* -------------------------------------------------------------------------- */
    /*                                    owner                                   */
    /* -------------------------------------------------------------------------- */
    /**
     * @notice Owner only - Updates the address of the discount signer
     * @param _signer Address of the discount signer
     */
    function setSigner(address _signer) external onlyOwner {
        if (_signer == address(0)) {
            _revert(SignerCannotBeZeroAddress.selector);
        }
        signer = _signer;

        emit SignerChanged(_signer);
    }

    /**
     * @notice Owner only - Updates the signerOnly flag
     * @param _signerOnly if true, episodes can only be purchased through signatures
     */
    function setSignerOnly(bool _signerOnly) external onlyOwner {
        signerOnly = _signerOnly;

        emit SignerOnlyChanged(_signerOnly);
    }

    /**
     * @notice Owner only - Updates the price per episode
     * @param _price Price per episode
     */
    function setPricePerEpisode(uint256 _price) external onlyOwner {
        pricePerEpisode = _price;

        emit PricePerEpisodeChanged(_price);
    }

    /* -------------------------------------------------------------------------- */
    /*                                    views                                   */
    /* -------------------------------------------------------------------------- */
    /**
     * @notice Returns the episodes purchased by the supplied address
     * @param account The address to check
     */
    function episodesOfOwner(address account) external view returns (uint256[] memory) {
        uint256[] memory episodes = new uint256[](MAX_EPISODE_ID+1);
        uint256 map = episodePurchasedBitmap[account];
        uint256 count;
        assembly {
            let i := 0
            let len := add(MAX_EPISODE_ID, 1)
            for {} lt(i, len) { i := add(i, 1) } {
                // Check if the bit is set
                if gt(and(map, shl(i, 1)), 0) {
                    count := add(count, 1)
                    mstore(add(episodes, mul(count, 0x20)), i)
                }
            }
        }

        // Resizing the array according to the count
        assembly {
            mstore(episodes, count)
        }
        return episodes;
    }

    function isSeasonPassHolder(address account) external view returns (bool) {
        return _isSeasonPassHolder(episodePurchasedBitmap[account]);
    }

    function _isSeasonPassHolder(uint256 bitmap) internal pure returns (bool) {
        return (bitmap & OWNS_SEASON_PASS_BITPOS) != 0;
    }

    /**
     * @notice Returns whether an episode has been purchased by the supplied address
     * @param account The address to check
     * @param account The episodeId to check
     * @dev Reverts if an episode does not exist (i.e. > MAX_EPISODE_ID)
     */
    function ownsEpisode(address account, uint256 episodeId) external view returns (bool) {
        if (episodeId > MAX_EPISODE_ID) {
            _revert(EpisodeDoesNotExist.selector);
        }
        uint256 map = episodePurchasedBitmap[account];
        if (_isSeasonPassHolder(map)) {
            return true;
        }
        return (map & (1 << episodeId)) != 0;
    }

    /* -------------------------------------------------------------------------- */
    /*                                  internal                                  */
    /* -------------------------------------------------------------------------- */
    function _revert(bytes4 code) internal pure {
        assembly {
            mstore(0x0, code)
            revert(0x0, 0x04)
        }
    }

    /**
     * @dev Checks whether a signature is valid for discount on purchase
     * @dev Reverts if now > expirationTimestamp
     * @dev Reverts if the signature is invalid
     * @param _discount the discount in basis point (e.g. 500 for 5% discount)
     * @param _expirationTimestamp the expiration timestamp for which this discount can be applied
     * @param signature the signature
     */
    function _checkDiscountSignature(
        uint256[] memory episodeIds,
        uint256 _discount,
        uint256 _expirationTimestamp,
        bytes memory signature
    ) internal view {
        bytes32 hash = keccak256(
            abi.encodePacked(
                msg.sender, episodeIds, _discount, block.chainid, address(this), _expirationTimestamp, "discount"
            )
        );

        if (block.timestamp > _expirationTimestamp) {
            _revert(VoucherExpired.selector);
        }
        if (hash.toEthSignedMessageHash().recover(signature) != signer) {
            _revert(InvalidSignature.selector);
        }
    }

    /**
     * @dev Checks whether a signature is valid for price  on purchase
     * @dev Reverts if now > expirationTimestamp
     * @dev Reverts if the signature is invalid
     * @param _totalPrice the total price for all the episodes
     * @param _expirationTimestamp the expiration timestamp for which this discount can be applied
     * @param signature the signature
     */
    function _checkTotalPriceSignature(
        uint256[] memory episodeIds,
        uint256 _totalPrice,
        uint256 _expirationTimestamp,
        bytes memory signature
    ) internal view {
        bytes32 hash = keccak256(
            abi.encodePacked(
                msg.sender, episodeIds, _totalPrice, block.chainid, address(this), _expirationTimestamp, "totalPrice"
            )
        );

        if (block.timestamp > _expirationTimestamp) {
            _revert(VoucherExpired.selector);
        }
        if (hash.toEthSignedMessageHash().recover(signature) != signer) {
            _revert(InvalidSignature.selector);
        }
    }

    /**
     * @dev Updates episodePurchasedBitmap for a user
     * @dev Reverts if any of the episodes does not exist
     * @dev Reverts if any of the episodes has been been purchased
     * @param user the address to be updated
     * @param episodeIds the IDs of the purchased episodes
     */
    function _grantEpisodes(address user, uint256[] memory episodeIds) internal {
        uint256 existingEpisodeBitmap = episodePurchasedBitmap[user];
        uint256 newEpisodeBitmap = existingEpisodeBitmap;

        // loop, check episodeId
        for (uint256 i; i < episodeIds.length;) {
            uint256 episodeId = episodeIds[i];

            // episode doesn't exist
            if (episodeId > MAX_EPISODE_ID) {
                _revert(EpisodeDoesNotExist.selector);
            }
            uint256 shiftedEpisodeId = 1 << episodeId;

            //buying 5 episodes is equivalent to buying the season pass, therefore, the episode CAN be repurchased only in this specific case.
            if (episodeIds.length != MAX_EPISODE_ID + 1) {
                // episode already purchased
                if ((existingEpisodeBitmap & shiftedEpisodeId) != 0) {
                    _revert(EpisodeAlreadyPurchased.selector);
                }
            }

            // update bitmap
            newEpisodeBitmap |= shiftedEpisodeId;

            // next loop
            unchecked {
                ++i;
            }
        }

        // got all episodes => season pass
        if (episodeIds.length == MAX_EPISODE_ID + 1) {
            newEpisodeBitmap |= OWNS_SEASON_PASS_BITPOS;
            emit SeasonPassPurchased(user);
        }

        // update
        episodePurchasedBitmap[user] = newEpisodeBitmap;

        emit EpisodesPurchased(user, episodeIds);
    }
}