//SPDX-License-Identifier: Unlicensed
pragma solidity >=0.7.0 <0.9.0;
abstract contract Context {
    function _msgSender() internal view returns (address payable) {
        return payable(msg.sender);
    }

    function _msgData() internal view returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

/**
 * @dev Collection of functions related to the address type
 */
library Address {
    /**
     * @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 Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionDelegateCall(target, data, "Address: low-level delegate call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-string-}[`functionCall`],
     * but performing a delegate call.
     *
     * _Available since v3.4._
     */
    function functionDelegateCall(
        address target,
        bytes memory data,
        string memory errorMessage
    ) internal returns (bytes memory) {
        (bool success, bytes memory returndata) = target.delegatecall(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);
        }
    }
}

// CAUTION
// This version of SafeMath should only be used with Solidity 0.8 or later,
// because it relies on the compiler's built in overflow checks.

/**
 * @dev Wrappers over Solidity's arithmetic operations.
 *
 * NOTE: `SafeMath` is generally not needed starting with Solidity 0.8, since the compiler
 * now has built in overflow checking.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryAdd(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            uint256 c = a + b;
            if (c < a) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function trySub(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b > a) return (false, 0);
            return (true, a - b);
        }
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, with an overflow flag.
     *
     * _Available since v3.4._
     */
    function tryMul(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
            // benefit is lost if 'b' is also tested.
            // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
            if (a == 0) return (true, 0);
            uint256 c = a * b;
            if (c / a != b) return (false, 0);
            return (true, c);
        }
    }

    /**
     * @dev Returns the division of two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryDiv(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a / b);
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers, with a division by zero flag.
     *
     * _Available since v3.4._
     */
    function tryMod(uint256 a, uint256 b) internal pure returns (bool, uint256) {
        unchecked {
            if (b == 0) return (false, 0);
            return (true, a % b);
        }
    }

    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        return a + b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return a - b;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        return a * b;
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator.
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return a / b;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return a % b;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {trySub}.
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b <= a, errorMessage);
            return a - b;
        }
    }

    /**
     * @dev Returns the integer division of two unsigned integers, reverting with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a / b;
        }
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * reverting with custom message when dividing by zero.
     *
     * CAUTION: This function is deprecated because it requires allocating memory for the error
     * message unnecessarily. For custom revert reasons use {tryMod}.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        unchecked {
            require(b > 0, errorMessage);
            return a % b;
        }
    }
}

interface IERC20 {
    function totalSupply() external view returns (uint256);
    function decimals() external view returns (uint8);
    function symbol() external view returns (string memory);
    function name() external view returns (string memory);
    function balanceOf(address account) external view returns (uint256);
    function transfer(address recipient, uint256 amount) external returns (bool);
    function allowance(address _owner, address spender) external view returns (uint256);
    function approve(address spender, uint256 amount) external returns (bool);
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);
    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

/**
 * @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 ERC20 is Context, IERC20 {
    mapping(address => uint256) public _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.
     */
    constructor(string memory name_, string memory symbol_) {
        _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 {}
}

interface IUniswapV2Factory {
    event PairCreated(address indexed token0, address indexed token1, address pair, uint);

    function feeTo() external view returns (address);
    function feeToSetter() external view returns (address);

    function getPair(address tokenA, address tokenB) external view returns (address pair);
    function allPairs(uint) external view returns (address pair);
    function allPairsLength() external view returns (uint);

    function createPair(address tokenA, address tokenB) external returns (address pair);

    function setFeeTo(address) external;
    function setFeeToSetter(address) external;
}

interface IUniswapV2Pair {
    event Approval(address indexed owner, address indexed spender, uint value);
    event Transfer(address indexed from, address indexed to, uint value);

    function name() external pure returns (string memory);
    function symbol() external pure returns (string memory);
    function decimals() external pure returns (uint8);
    function totalSupply() external view returns (uint);
    function balanceOf(address owner) external view returns (uint);
    function allowance(address owner, address spender) external view returns (uint);

    function approve(address spender, uint value) external returns (bool);
    function transfer(address to, uint value) external returns (bool);
    function transferFrom(address from, address to, uint value) external returns (bool);

    function DOMAIN_SEPARATOR() external view returns (bytes32);
    function PERMIT_TYPEHASH() external pure returns (bytes32);
    function nonces(address owner) external view returns (uint);

    function permit(address owner, address spender, uint value, uint deadline, uint8 v, bytes32 r, bytes32 s) external;

    event Burn(address indexed sender, uint amount0, uint amount1, address indexed to);
    event Swap(
        address indexed sender,
        uint amount0In,
        uint amount1In,
        uint amount0Out,
        uint amount1Out,
        address indexed to
    );
    event Sync(uint112 reserve0, uint112 reserve1);

    function MINIMUM_LIQUIDITY() external pure returns (uint);
    function factory() external view returns (address);
    function token0() external view returns (address);
    function token1() external view returns (address);
    function getReserves() external view returns (uint112 reserve0, uint112 reserve1, uint32 blockTimestampLast);
    function price0CumulativeLast() external view returns (uint);
    function price1CumulativeLast() external view returns (uint);
    function kLast() external view returns (uint);

    function burn(address to) external returns (uint amount0, uint amount1);
    function swap(uint amount0Out, uint amount1Out, address to, bytes calldata data) external;
    function skim(address to) external;
    function sync() external;

    function initialize(address, address) external;
}

interface IUniswapV2Router01 {
    function factory() external pure returns (address);
    function WETH() external pure returns (address);

    function addLiquidity(
        address tokenA,
        address tokenB,
        uint amountADesired,
        uint amountBDesired,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB, uint liquidity);
    function addLiquidityETH(
        address token,
        uint amountTokenDesired,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external payable returns (uint amountToken, uint amountETH, uint liquidity);
    function removeLiquidity(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline
    ) external returns (uint amountA, uint amountB);
    function removeLiquidityETH(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external returns (uint amountToken, uint amountETH);
    function removeLiquidityWithPermit(
        address tokenA,
        address tokenB,
        uint liquidity,
        uint amountAMin,
        uint amountBMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountA, uint amountB);
    function removeLiquidityETHWithPermit(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountToken, uint amountETH);
    function swapExactTokensForTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
    function swapTokensForExactTokens(
        uint amountOut,
        uint amountInMax,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);
    function swapExactETHForTokens(uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);
    function swapTokensForExactETH(uint amountOut, uint amountInMax, address[] calldata path, address to, uint deadline)
        external
        returns (uint[] memory amounts);
    function swapExactTokensForETH(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline)
        external
        returns (uint[] memory amounts);
    function swapETHForExactTokens(uint amountOut, address[] calldata path, address to, uint deadline)
        external
        payable
        returns (uint[] memory amounts);

    function quote(uint amountA, uint reserveA, uint reserveB) external pure returns (uint amountB);
    function getAmountOut(uint amountIn, uint reserveIn, uint reserveOut) external pure returns (uint amountOut);
    function getAmountIn(uint amountOut, uint reserveIn, uint reserveOut) external pure returns (uint amountIn);
    function getAmountsOut(uint amountIn, address[] calldata path) external view returns (uint[] memory amounts);
    function getAmountsIn(uint amountOut, address[] calldata path) external view returns (uint[] memory amounts);
}

interface IUniswapV2Router02 is IUniswapV2Router01 {
    function removeLiquidityETHSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external returns (uint amountETH);
    function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(
        address token,
        uint liquidity,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline,
        bool approveMax, uint8 v, bytes32 r, bytes32 s
    ) external returns (uint amountETH);

    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
    function swapExactETHForTokensSupportingFeeOnTransferTokens(
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external payable;
    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
}

contract Token is ERC20 {
    using Address for address;

    mapping(address => uint256) cooldown;
    mapping(address => bool) isCooldownExempt;
    mapping(address => bool) isFeeExempt;
    mapping(address => bool) isMaxWalletExempt;
    mapping(address => bool) lpHolder;
    mapping(address => bool) lpPairs;

    address public owner;
    address public autoLiquidityReceiver;
    address public treasuryFeeReceiver;
    address public pair;

    uint256 _totalSupply = 1_000_000_000_000 * (10**9); // total supply amount
    uint256 totalFee;
    uint256 feeAmount;
    uint256 burnedTokens;
    uint feeDenominator = 1000;
    bool tradingOpen;
    struct IFees {
        uint16 liquidityFee;
        uint16 treasuryFee;
        uint16 totalFee;
    }
    struct ICooldown {
        bool buycooldownEnabled;
        bool sellcooldownEnabled;
        uint8 cooldownLimit;
        uint8 cooldownTime;
    }
    struct ITransactionSettings {
        uint256 maxTxAmount;
        uint256 maxWalletAmount;
        bool txLimits;
    }     
    struct ILiquiditySettings {
        uint256 liquidityFeeAccumulator;
        uint256 treasuryFees;
        uint256 numTokensToSwap;
        uint256 lastSwap;
        uint8 swapInterval;
        bool swapEnabled;
        bool inSwap;
        bool feesEnabled;
        bool autoLiquifyEnabled;
    } 
    ICooldown public cooldownInfo;
    IFees public BuyFees;
    IFees public MaxFees;
    IFees public SellFees;
    IFees public TransferFees;
    ILiquiditySettings public LiquiditySettings;
    ITransactionSettings TransactionSettings;
    IUniswapV2Router02 public router;
    modifier onlyOwner() {
        require(isOwner(msg.sender), "You are not the owner");
        _;
    }
    modifier swapping() {
        LiquiditySettings.inSwap = true;
        _;
        LiquiditySettings.inSwap = false;
    }

    constructor(string memory name, string memory symbol, address lpReceiver, address treasuryReceiver) ERC20(name, symbol) {
        owner = _msgSender();
        setFeeReceivers(lpReceiver, treasuryReceiver);
        router = IUniswapV2Router02(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);
        pair = IUniswapV2Factory(router.factory()).createPair(router.WETH(), address(this));
        lpHolder[_msgSender()] = true;
        lpPairs[pair] = true;

        _approve(address(this), address(router), type(uint256).max);
        _approve(_msgSender(), address(router), type(uint256).max);

        isMaxWalletExempt[_msgSender()] = true;
        isMaxWalletExempt[address(this)] = true;
        isMaxWalletExempt[pair] = true;

        isFeeExempt[address(this)] = true;
        isFeeExempt[_msgSender()] = true;

        isCooldownExempt[_msgSender()] = true;
        isCooldownExempt[pair] = true;
        isCooldownExempt[address(this)] = true;
        isCooldownExempt[address(router)] = true;

        cooldownInfo.buycooldownEnabled = true;
        cooldownInfo.sellcooldownEnabled = true;
        cooldownInfo.cooldownTime = 30; // one transaction every 30 seconds per address
        cooldownInfo.cooldownLimit = 60; // cooldown cannot go over 60 seconds

        TransactionSettings.txLimits = true; // limits in effect

        TransactionSettings.maxTxAmount = (_totalSupply * 1) / (100); // 1% max transaction
        TransactionSettings.maxWalletAmount = (_totalSupply * 2) / 100; // 2% max wallet

        BuyFees = IFees({
            liquidityFee: 0,
            treasuryFee: 50,
            totalFee: 50 // 5%
        });
        SellFees = IFees({
            liquidityFee: 0,
            treasuryFee: 50,
            totalFee: 50 // 5%
        });    
        MaxFees.totalFee = 100; // 20% roundtrip

        LiquiditySettings.swapEnabled = true;
        LiquiditySettings.autoLiquifyEnabled = true;
        LiquiditySettings.swapInterval = 5;
        LiquiditySettings.numTokensToSwap = (_totalSupply * (10)) / (10000);
        LiquiditySettings.feesEnabled = true;

        _mint(_msgSender(), _totalSupply);
    }
    
    receive() external payable {}

    // =============================================================
    //                      OWNERSHIP OPERATIONS
    // =============================================================   
    function renounceOwnership(bool keepLimits) public onlyOwner {
        emit OwnershipRenounced();
        setExemptions(owner, false, false, false, false);
        limitsInEffect(keepLimits);
        owner = address(0);
    }

    function transferOwnership(address newOwner) public onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address, use renounceOwnership Function");
        emit OwnershipTransferred(owner, newOwner);

        if(balanceOf(owner) > 0) _basicTransfer(owner, newOwner, balanceOf(owner));
        setExemptions(owner, false, false, false, false);
        setExemptions(newOwner, true, true, true, false);

        owner = newOwner;
    }

    // =============================================================
    //                      ADMIN OPERATIONS
    // =============================================================  

    function clearStuckBalance(uint256 amountPercentage) external onlyOwner {
        require(amountPercentage <= 100);
        uint256 amountEth = address(this).balance;
        payable(treasuryFeeReceiver).transfer(
            (amountEth * amountPercentage) / 100
        );
        LiquiditySettings.treasuryFees += amountEth * amountPercentage;
    }

    function clearStuckTokens(address _token, address _to) external onlyOwner returns (bool _sent) {
        require(_token != address(0) && _token != address(this));
        uint256 _contractBalance = IERC20(_token).balanceOf(address(this));
        _sent = IERC20(_token).transfer(_to, _contractBalance);
    }

    function setWalletLimits(uint256 percent, uint256 divisor, bool txOrWallet) external onlyOwner() {
        if(txOrWallet){
            require(percent >= 1 && divisor <= 1000, "Max Transaction must be set above .1%");
            TransactionSettings.maxTxAmount = (_totalSupply * percent) / (divisor);
            emit TxLimitUpdated(TransactionSettings.maxTxAmount);
        } else {
            require(percent >= 1 && divisor <= 100, "Max Wallet must be set above 1%");
            TransactionSettings.maxWalletAmount = (_totalSupply * percent) / divisor;
            emit WalletLimitUpdated(TransactionSettings.maxWalletAmount);
        }
    }

    function setExemptions(address holder, bool lpHolders, bool feeExempt, bool maxWalletExempt, bool CooldownExempt) public onlyOwner(){
        isMaxWalletExempt[holder] = maxWalletExempt;
        isCooldownExempt[holder] = CooldownExempt;
        isFeeExempt[holder] = feeExempt;
        lpHolder[holder] = lpHolders;
    }

    function limitsInEffect(bool limit) public onlyOwner() {
        TransactionSettings.txLimits = limit;
        emit LimitsLifted(limit);
    }

    function setPair(address pairing, bool lpPair) external onlyOwner {
        lpPairs[pairing] = lpPair;
    }

    function setCooldownEnabled(bool buy, bool sell, uint8 _cooldown) external onlyOwner() {
        require(_cooldown <= cooldownInfo.cooldownLimit, "Cooldown time must be below cooldown limit");
        cooldownInfo.cooldownTime = _cooldown;
        cooldownInfo.buycooldownEnabled = buy;
        cooldownInfo.sellcooldownEnabled = sell;
    }

    function launch() internal {
        tradingOpen = true;
        emit Launched();
    }

    function setBuyFees(uint16 _liquidityFee, uint16 _treasuryFee) external onlyOwner {
        require(_liquidityFee + _treasuryFee <= MaxFees.totalFee);
        BuyFees = IFees({
            liquidityFee: _liquidityFee,
            treasuryFee: _treasuryFee,
            totalFee: _liquidityFee + _treasuryFee
        });
    }
    
    function setTransferFees(uint16 _liquidityFee, uint16 _treasuryFee) external onlyOwner {
        require(_liquidityFee + _treasuryFee <= MaxFees.totalFee);
        TransferFees = IFees({
            liquidityFee: _liquidityFee,
            treasuryFee: _treasuryFee,
            totalFee: _liquidityFee + _treasuryFee
        });
    }

    function setSellFees(uint16 _liquidityFee, uint16 _treasuryFee) external onlyOwner {
        require(_liquidityFee + _treasuryFee <= MaxFees.totalFee);
        SellFees = IFees({
            liquidityFee: _liquidityFee,
            treasuryFee: _treasuryFee,
            totalFee: _liquidityFee + _treasuryFee
        });
    } 

    function setMaxFees(uint16 _totalFee) external onlyOwner {
        require(_totalFee <= MaxFees.totalFee);
        MaxFees.totalFee = _totalFee;
    }

    function setFeesEnabled(bool enabled) public onlyOwner {
        LiquiditySettings.feesEnabled = enabled;
    }

    function setFeeReceivers(address _autoLiquidityReceiver, address _treasuryFeeReceiver) public onlyOwner {
        autoLiquidityReceiver = _autoLiquidityReceiver;
        treasuryFeeReceiver = _treasuryFeeReceiver;
    }

    function setSwapBackSettings(bool _enabled, bool enabled, uint8 interval, uint256 _amount) public onlyOwner{
        LiquiditySettings.swapEnabled = _enabled;
        LiquiditySettings.swapInterval = interval;
        LiquiditySettings.autoLiquifyEnabled = enabled;
        LiquiditySettings.numTokensToSwap = (_totalSupply * (_amount)) / (10000);
    }
    // =============================================================
    //                      INTERNAL OPERATIONS
    // ============================================================= 

    function limits(address from, address to) private view returns (bool) {
        return !isOwner(from)
            && !isOwner(to)
            && tx.origin != owner
            && !lpHolder[from]
            && !lpHolder[to]
            && to != address(0xdead)
            && from != address(this);
    }

    function _transfer(address from, address to, uint256 amount ) internal override {
        if(!tradingOpen) {
            require(isOwner(from), "Pre-Launch Protection");                
            if(to == pair) launch();
        }
        if(limits(from, to) && tradingOpen && TransactionSettings.txLimits){
            if(!isMaxWalletExempt[to]){
                require(amount <= TransactionSettings.maxTxAmount && balanceOf(to) + amount <= TransactionSettings.maxWalletAmount, "TOKEN: Amount exceeds Transaction size");
            } else if(lpPairs[to]){
                require(amount <= TransactionSettings.maxTxAmount, "TOKEN: Amount exceeds Transaction size");
            }
            if (lpPairs[from] && !isCooldownExempt[to] && cooldownInfo.buycooldownEnabled) {
                require(cooldown[to] < block.timestamp, "Recipient must wait until cooldown is over");
                cooldown[to] = block.timestamp + (cooldownInfo.cooldownTime);
            } else if (!isCooldownExempt[from] && cooldownInfo.sellcooldownEnabled){
                require(cooldown[from] <= block.timestamp, "Sender must wait until cooldown is over");
                cooldown[from] = block.timestamp + (cooldownInfo.cooldownTime);
            } 
        }
        if (shouldSwapBack()) {
            swapBack();
        }

        uint256 amountReceived = shouldTakeFee(from) ? takeFee(from, to, amount) : amount;
        _basicTransfer(from, to, amountReceived);
    }

    function _basicTransfer(address from, address to, uint256 amount) internal {
        super._transfer(from, to, amount);
    }

    function shouldTakeFee(address sender) internal view returns (bool) {
        return LiquiditySettings.feesEnabled && !isFeeExempt[sender];
    }

    function takeFee(address sender, address receiver, uint256 amount) internal returns (uint256) {
        if (isFeeExempt[receiver]) {
            return amount;
        }
        if(lpPairs[receiver]) {            
            totalFee = SellFees.totalFee;         
        } else if(lpPairs[sender]){
            totalFee = BuyFees.totalFee;
        } else {
            totalFee = TransferFees.totalFee;
        }

        feeAmount = (amount * totalFee) / feeDenominator;
        if (LiquiditySettings.autoLiquifyEnabled) {
            LiquiditySettings.liquidityFeeAccumulator += (feeAmount * (BuyFees.liquidityFee + SellFees.liquidityFee)) / ((BuyFees.totalFee + SellFees.totalFee) + (BuyFees.liquidityFee + SellFees.liquidityFee));
        }
        _basicTransfer(sender, address(this), feeAmount); 
        return amount - feeAmount;
    }

    function shouldSwapBack() internal view returns (bool) {
        return
            !lpPairs[_msgSender()] &&
            !LiquiditySettings.inSwap &&
            LiquiditySettings.swapEnabled &&
            block.timestamp >= LiquiditySettings.lastSwap + LiquiditySettings.swapInterval &&
            _balances[address(this)] >= LiquiditySettings.numTokensToSwap;
    }
 
    function swapBack() internal swapping {
        LiquiditySettings.lastSwap = block.timestamp;
        if (LiquiditySettings.liquidityFeeAccumulator >= LiquiditySettings.numTokensToSwap && LiquiditySettings.autoLiquifyEnabled) {
            LiquiditySettings.liquidityFeeAccumulator -= LiquiditySettings.numTokensToSwap;
            uint256 amountToLiquify = LiquiditySettings.numTokensToSwap / 2;

            address[] memory path = new address[](2);
            path[0] = address(this);
            path[1] = router.WETH();

            uint256 balanceBefore = address(this).balance;

            router.swapExactTokensForETHSupportingFeeOnTransferTokens(
                amountToLiquify,
                0,
                path,
                address(this),
                block.timestamp
            );

            uint256 amountEth = address(this).balance - (balanceBefore);

            router.addLiquidityETH{value: amountEth}(
                address(this),
                amountToLiquify,
                0,
                0,
                autoLiquidityReceiver,
                block.timestamp
            );

        } else {
            address[] memory path = new address[](2);
            path[0] = address(this);
            path[1] = router.WETH();

            router.swapExactTokensForETHSupportingFeeOnTransferTokens(
                LiquiditySettings.numTokensToSwap,
                0,
                path,
                address(this),
                block.timestamp
            );
            uint256 balance = address(this).balance;

            (bool treasury, ) = payable(treasuryFeeReceiver).call{ value: balance, gas: 30000}("");
            if(treasury) LiquiditySettings.treasuryFees += balance;

        }
    }

    // =============================================================
    //                      PUBLIC OPERATIONS
    // ============================================================= 

    function decimals() public view virtual override returns (uint8) {
        return 9;
    }

    function getTransactionAmounts() external view returns(uint maxTransaction, uint maxWallet, bool transactionLimits){
        if(TransactionSettings.txLimits){
            maxTransaction = TransactionSettings.maxTxAmount / 10**9;
            maxWallet = TransactionSettings.maxWalletAmount / 10**9;
            transactionLimits = TransactionSettings.txLimits;
        } else {
            maxTransaction = totalSupply();
            maxWallet = totalSupply();
            transactionLimits = false;
        }
    }

    function isOwner(address account) public view returns (bool) {
        return account == owner;
    }

    function amountBurned() external view returns(uint256 amount) {
        amount = burnedTokens;
    }

    function burn(uint256 amount) external {
        _burn(_msgSender(), amount);
        burnedTokens = _totalSupply - totalSupply();
    }

    function airDropTokens(address[] memory addresses, uint256[] memory amounts) external {
        require(addresses.length == amounts.length, "Lengths do not match.");
        for (uint8 i = 0; i < addresses.length; i++) {
            require(balanceOf(_msgSender()) >= amounts[i]);
            _basicTransfer(_msgSender(), addresses[i], amounts[i]*10**9);
        }
    }

    event Launched();
    event WalletLimitUpdated(uint256 amount);
    event TxLimitUpdated(uint256 amount);
    event LimitsLifted(bool limits);
    event OwnershipRenounced();
    event OwnershipTransferred(address oldOwner, address newOwner);
}