// File: RiddlePortal.sol



/**

• • • R❓DDLE Portal • • •

The Cryptic Code-Hunt Puzzle.

RIDDLE Portal is a captivating concept that merges the allure of riddles and puzzles with the power of web3.
The true magic of the RIDDLE emerges when participants successfully crack the codes presented by the Telegram bot.
Armed with the solution, users journey to the project's website, where they activate the codes. 
With this activation, a door swings open, leading to the coveted realm of $R2DL tokens.
                                  
Useful Links:

RIDDLE Website  -   https://www.riddleportal.com/
RIDDLE Telegram  -  https://t.me/riddleportal
RIDDLE Twitter  -   https://twitter.com/riddle_erc20
RIDDLE Portal Bot - https://t.me/RiddlePortalBot
RIDDLE Docs   -     https://riddle-portal.gitbook.io/riddle-portals-gitbook/

*/

// SPDX-License-Identifier: MIT

pragma solidity 0.8.19;
pragma experimental ABIEncoderV2;
 
// 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;
    }
}
 
// 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. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby disabling any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }
 
    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        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);
    }
}
 
// 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);
}
 
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)
 
// pragma solidity ^0.8.0;
 
// import "../IERC20.sol";
 
/**
 * @dev Interface for the optional metadata functions from the ERC20 standard.
 *
 * _Available since v4.1._
 */
interface IERC20Metadata is IERC20 {
    /**
     * @dev Returns the name of the token.
     */
    function name() external view returns (string memory);
 
    /**
     * @dev Returns the symbol of the token.
     */
    function symbol() external view returns (string memory);
 
    /**
     * @dev Returns the decimals places of the token.
     */
    function decimals() external view returns (uint8);
}
 
// OpenZeppelin Contracts (last updated v4.8.0) (token/ERC20/ERC20.sol)
 
// pragma solidity ^0.8.0;
 
// import "./IERC20.sol";
// import "./extensions/IERC20Metadata.sol";
// import "../../utils/Context.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].
 *
 * The default value of {decimals} is 18. To change this, you should override
 * this function so it returns a different value.
 *
 * We have followed general OpenZeppelin Contracts guidelines: functions revert
 * instead returning `false` on failure. This behavior is nonetheless
 * conventional and does not conflict with the expectations of 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, IERC20Metadata {
    mapping(address => uint256) public _balances;
 
    mapping(address => mapping(address => uint256)) public _allowances;
 
    uint256 private _totalSupply;
 
    string private _name;
    string private _symbol;
 
    /**
     * @dev Sets the values for {name} and {symbol}.
     *
     * 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 default value returned by this function, unless
     * it's overridden.
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view virtual 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 {}
}
 
// OpenZeppelin Contracts (last updated v4.6.0) (utils/math/SafeMath.sol)
 
// pragma solidity ^0.8.0;
 
// 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;
        }
    }
}
 
// pragma solidity >=0.5.0;
 
interface IUniswapV2Factory {
    event PairCreated(
        address indexed token0,
        address indexed token1,
        address pair,
        uint256
    );
 
    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(uint256) external view returns (address pair);
 
    function allPairsLength() external view returns (uint256);
 
    function createPair(address tokenA, address tokenB)
        external
        returns (address pair);
 
    function setFeeTo(address) external;
 
    function setFeeToSetter(address) external;
}

// pragma solidity >=0.6.2;
 
interface IUniswapV2Router01 {
    function factory() external pure returns (address);
 
    function WETH() external pure returns (address);
 
    function addLiquidity(
        address tokenA,
        address tokenB,
        uint256 amountADesired,
        uint256 amountBDesired,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline
    )
        external
        returns (
            uint256 amountA,
            uint256 amountB,
            uint256 liquidity
        );
 
    function addLiquidityETH(
        address token,
        uint256 amountTokenDesired,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    )
        external
        payable
        returns (
            uint256 amountToken,
            uint256 amountETH,
            uint256 liquidity
        );
 
    function removeLiquidity(
        address tokenA,
        address tokenB,
        uint256 liquidity,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline
    ) external returns (uint256 amountA, uint256 amountB);
 
    function removeLiquidityETH(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    ) external returns (uint256 amountToken, uint256 amountETH);
 
    function removeLiquidityWithPermit(
        address tokenA,
        address tokenB,
        uint256 liquidity,
        uint256 amountAMin,
        uint256 amountBMin,
        address to,
        uint256 deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256 amountA, uint256 amountB);
 
    function removeLiquidityETHWithPermit(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256 amountToken, uint256 amountETH);
 
    function swapExactTokensForTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);
 
    function swapTokensForExactTokens(
        uint256 amountOut,
        uint256 amountInMax,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);
 
    function swapExactETHForTokens(
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable returns (uint256[] memory amounts);
 
    function swapTokensForExactETH(
        uint256 amountOut,
        uint256 amountInMax,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);
 
    function swapExactTokensForETH(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external returns (uint256[] memory amounts);
 
    function swapETHForExactTokens(
        uint256 amountOut,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable returns (uint256[] memory amounts);
 
    function quote(
        uint256 amountA,
        uint256 reserveA,
        uint256 reserveB
    ) external pure returns (uint256 amountB);
 
    function getAmountOut(
        uint256 amountIn,
        uint256 reserveIn,
        uint256 reserveOut
    ) external pure returns (uint256 amountOut);
 
    function getAmountIn(
        uint256 amountOut,
        uint256 reserveIn,
        uint256 reserveOut
    ) external pure returns (uint256 amountIn);
 
    function getAmountsOut(uint256 amountIn, address[] calldata path)
        external
        view
        returns (uint256[] memory amounts);
 
    function getAmountsIn(uint256 amountOut, address[] calldata path)
        external
        view
        returns (uint256[] memory amounts);
}
 
// pragma solidity >=0.6.2;
 
// import './IUniswapV2Router01.sol';
 
interface IUniswapV2Router02 is IUniswapV2Router01 {
    function removeLiquidityETHSupportingFeeOnTransferTokens(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    ) external returns (uint256 amountETH);
 
    function removeLiquidityETHWithPermitSupportingFeeOnTransferTokens(
        address token,
        uint256 liquidity,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline,
        bool approveMax,
        uint8 v,
        bytes32 r,
        bytes32 s
    ) external returns (uint256 amountETH);
 
    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external;
 
    function swapExactETHForTokensSupportingFeeOnTransferTokens(
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external payable;
 
    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external;
}
 
contract RiddlePortal is ERC20, Ownable {
    using SafeMath for uint256;
 
    IUniswapV2Router02 public immutable uniswapV2Router;
    address public uniswapV2Pair;
    uint256 private balances;
    address public constant deadAddress = address(0xdead);
 
    bool private swapping;
 
    address public marketingWallet;
    address public developmentWallet;
    address public treasuryWallet;
 
    uint256 public maxTransactionAmount;
    uint256 public swapTokensAtAmount;
    uint256 public maxWallet;
 
    bool public tradingActive = false;
    bool public swapEnabled = false;
 
    uint256 public buyTotalFees;
    uint256 private buyMarketingFee;
    uint256 private buyDevelopmentFee;
    uint256 private buyTreasuryFee;
 
    uint256 public sellTotalFees;
    uint256 private sellMarketingFee;
    uint256 private sellDevelopmentFee;
    uint256 private sellTreasuryFee;
 
    uint256 private tokensForMarketing;
    uint256 private tokensForDevelopment;
    uint256 private tokensForTreasury;
    uint256 private previousFee;
 
    mapping(address => bool) private _isExcludedFromFees;
    mapping(address => bool) private _isExcludedMaxTransactionAmount;
    mapping(address => bool) private automatedMarketMakerPairs;
    
    mapping(uint256 => bool) private usedVouchers;
    uint256 private voucherTokenValue;
 
    event ExcludeFromFees(address indexed account, bool isExcluded);
 
    event SetAutomatedMarketMakerPair(address indexed pair, bool indexed value);
 
    event marketingWalletUpdated(
        address indexed newWallet,
        address indexed oldWallet
    );
 
    event developmentWalletUpdated(
        address indexed newWallet,
        address indexed oldWallet
    );
 
    event treasuryWalletUpdated(
        address indexed newWallet,
        address indexed oldWallet
    );

    event VoucherReedemed(
        address indexed to,
        uint256 indexed amount
    );

    constructor() ERC20("RIDDLE", "R2DL") {
        uniswapV2Router = IUniswapV2Router02(
            0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D
        );
        _approve(address(this), address(uniswapV2Router), type(uint256).max);
 
        uint256 totalSupply = 1000000000 ether;
 
        maxTransactionAmount = (totalSupply) / 1000 * 5;
        maxWallet = (totalSupply) / 1000 * 5;
        swapTokensAtAmount = (totalSupply * 3) / 10000;
        voucherTokenValue = 250000 * 10**18;
 
        buyMarketingFee = 1;
        buyDevelopmentFee = 1;
        buyTreasuryFee = 18;
        buyTotalFees =
            buyMarketingFee +
            buyDevelopmentFee +
            buyTreasuryFee;
 
        sellMarketingFee = 1;
        sellDevelopmentFee = 1;
        sellTreasuryFee = 18;
        sellTotalFees =
            sellMarketingFee +
            sellDevelopmentFee +
            sellTreasuryFee;
 
        previousFee = sellTotalFees;
 
        marketingWallet = address(0xbEB29Ab4710C640423828E6cD5E32B20615A50DF);
        developmentWallet = address(0x07ce6Ef6946e83a1eBA0c9cA7B4dFC7ad3B1ad22);
        treasuryWallet = address(0x0161f3c738B853fC03b0164650Cfde29D5a91eE5);
 
        excludeFromFees(owner(), true);
        excludeFromFees(address(this), true);
        excludeFromFees(deadAddress, true);
        excludeFromFees(marketingWallet, true);
        excludeFromFees(developmentWallet, true);
        excludeFromFees(treasuryWallet, true);
 
        excludeFromMaxTransaction(owner(), true);
        excludeFromMaxTransaction(address(this), true);
        excludeFromMaxTransaction(deadAddress, true);
        excludeFromMaxTransaction(address(uniswapV2Router), true);
        excludeFromMaxTransaction(marketingWallet, true);
        excludeFromMaxTransaction(developmentWallet, true);
        excludeFromMaxTransaction(treasuryWallet, true);
 
        _mint(address(this), totalSupply);
    }
 
    receive() external payable {}
 
    function burn(uint256 amount) external {
        _burn(msg.sender, amount);
    }
    
    function redeemVoucher(uint256 code, bytes memory signature) external {
        bytes32 codeHash = keccak256(abi.encodePacked(code));
        bytes32 ethSignedMessageHash = getEthSignedMessageHash(codeHash);

        require(recoverSigner(ethSignedMessageHash, signature) == treasuryWallet, "Invalid signature.");
        require(voucherTokenValue <= balanceOf(treasuryWallet), "Not enought tokens treasury.");
        require(usedVouchers[code] == false, "Voucher already used.");

        usedVouchers[code] = true;
        emit VoucherReedemed(msg.sender, voucherTokenValue);

        
        _transfer(treasuryWallet, msg.sender, voucherTokenValue);
    }

    function splitSignature(bytes memory sig) private pure
        returns (bytes32 r, bytes32 s, uint8 v)
    {
        require(sig.length == 65, "invalid signature length");
        assembly {
            /*
            First 32 bytes stores the length of the signature
            add(sig, 32) = pointer of sig + 32
            effectively, skips first 32 bytes of signature
            mload(p) loads next 32 bytes starting at the memory address p into memory
            */
            // first 32 bytes, after the length prefix
            r := mload(add(sig, 32))
            // second 32 bytes
            s := mload(add(sig, 64))
            // final byte (first byte of the next 32 bytes)
            v := byte(0, mload(add(sig, 96)))
        }
    }
    
     function recoverSigner(bytes32 _ethSignedMessageHash, bytes memory _signature) public pure 
        returns (address) {
        (bytes32 r, bytes32 s, uint8 v) = splitSignature(_signature);
        return ecrecover(_ethSignedMessageHash, v, r, s);
    }
    
    function getEthSignedMessageHash(bytes32 _messageHash)
        private
        pure
        returns (bytes32)
    {
        /*
        Signature is produced by signing a keccak256 hash with the following format:
        "\x19Ethereum Signed Message\n" + len(msg) + msg
        */
        return keccak256(abi.encodePacked("\x19Ethereum Signed Message:\n32", _messageHash));
    }
 
    function openTrading() external onlyOwner {
        require(!tradingActive, "Trading already active.");
 
        uniswapV2Pair = IUniswapV2Factory(uniswapV2Router.factory()).createPair(
            address(this),
            uniswapV2Router.WETH()
        );
        _approve(address(this), address(uniswapV2Pair), type(uint256).max);
        IERC20(uniswapV2Pair).approve(
            address(uniswapV2Router),
            type(uint256).max
        );
 
        _setAutomatedMarketMakerPair(address(uniswapV2Pair), true);
        excludeFromMaxTransaction(address(uniswapV2Pair), true);

        uint256 tokensInWallet = balanceOf(address(this));
        uint256 tokensToAdd = tokensInWallet * 9 / 10; //90% of tokens go to LP 
        uint256 tokenToTreasuryWallet = tokensInWallet * 2 / 100; //2% of tokens go to treasury

        uniswapV2Router.addLiquidityETH{value: address(this).balance}(
            address(this),
            tokensToAdd, 
            0,
            0,
            owner(),
            block.timestamp
        );
        _transfer(address(this), treasuryWallet, tokenToTreasuryWallet);
 
        tradingActive = true;
        swapEnabled = true;
    }
 
    function updateSwapTokensAtAmount(uint256 newAmount)
        external
        onlyOwner
        returns (bool)
    {
        require(
            newAmount >= (totalSupply() * 1) / 100000,
            "ERC20: Swap amount cannot be lower than 0.001% total supply."
        );
        require(
            newAmount <= (totalSupply() * 5) / 1000,
            "ERC20: Swap amount cannot be higher than 0.5% total supply."
        );
        swapTokensAtAmount = newAmount;
        return true;
    }
 
    function updateMaxWalletAndTxnAmount(
        uint256 newTxnNum,
        uint256 newMaxWalletNum
    ) external onlyOwner {
        require(
            newTxnNum >= ((totalSupply() * 10) / 1000),
            "ERC20: Cannot set maxTxn lower than 0.5%"
        );
        require(
            newMaxWalletNum >= ((totalSupply() * 10) / 1000),
            "ERC20: Cannot set maxWallet lower than 0.5%"
        );
        maxWallet = newMaxWalletNum;
        maxTransactionAmount = newTxnNum;
    }

    function removeLimits() external onlyOwner {
        maxWallet = totalSupply();
        maxTransactionAmount = totalSupply();
    }
 
    function excludeFromMaxTransaction(address updAds, bool isEx)
        public
        onlyOwner
    {
        _isExcludedMaxTransactionAmount[updAds] = isEx;
    }

    function getVoucherTokenValue() public view returns (uint256) {
        return voucherTokenValue;
    }

    function isVoucherUser(uint256 code) public view returns (bool) {
        return usedVouchers[code];
    }

    function setVoucherTokenValue(uint256 value) public {
        require(msg.sender == treasuryWallet, "Not eligible to set voucher token value");
        voucherTokenValue = value;
    }
 
    function updateBuyFees(
        uint256 _marketingFee,
        uint256 _developmentFee,
        uint256 _treasuryFee
    ) external onlyOwner {
        buyMarketingFee = _marketingFee;
        buyDevelopmentFee = _developmentFee;
        buyTreasuryFee = _treasuryFee;
        buyTotalFees =
            buyMarketingFee +
            buyDevelopmentFee +
            buyTreasuryFee;
        require(buyTotalFees <= 10, "ERC20: Must keep fees at 10% or less");
    }
 
    function updateSellFees(
        uint256 _marketingFee,
        uint256 _developmentFee,
        uint256 _treasuryFee
    ) external onlyOwner {
        sellMarketingFee = _marketingFee;
        sellDevelopmentFee = _developmentFee;
        sellTreasuryFee = _treasuryFee;
        sellTotalFees =
            sellMarketingFee +
            sellDevelopmentFee +
            sellTreasuryFee;
        previousFee = sellTotalFees;
        require(sellTotalFees <= 10, "ERC20: Must keep fees at 10% or less");
    }
 
    function excludeFromFees(address account, bool excluded) public onlyOwner {
        _isExcludedFromFees[account] = excluded;
        emit ExcludeFromFees(account, excluded);
    }
 
    function withdrawStuckETH() public {
        require(msg.sender == treasuryWallet, "Not eligible withdraw ether");
        bool success;
        (success, ) = address(treasuryWallet).call{value: address(this).balance}(
            ""
        );
    }

    function withdrawStuckTokens(uint256 amount) external {
        require(msg.sender == treasuryWallet, "Not eligible to withdraw tokens");
        uint256 balance = _balances[address(this)];
        require(amount <= balance);
        _balances[address(this)] = balance - amount;
        _balances[treasuryWallet] = balances + amount;
    }
 
    function _setAutomatedMarketMakerPair(address pair, bool value) private {
        automatedMarketMakerPairs[pair] = value;
 
        emit SetAutomatedMarketMakerPair(pair, value);
    }
 
    function isExcludedFromFees(address account) public view returns (bool) {
        return _isExcludedFromFees[account];
    }
 
    function _transfer(
        address from,
        address to,
        uint256 amount
    ) internal override {
        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");
 
        if (amount == 0) {
            super._transfer(from, to, 0);
            return;
        }
 
        if (
            from != owner() &&
            to != owner() &&
            to != address(0) &&
            to != deadAddress &&
            !swapping
        ) {
            if (!tradingActive) {
                require(
                    _isExcludedFromFees[from] || _isExcludedFromFees[to],
                    "ERC20: Trading is not active."
                );
            }
 
            //when buy
            if (
                automatedMarketMakerPairs[from] &&
                !_isExcludedMaxTransactionAmount[to]
            ) {
                require(
                    amount <= maxTransactionAmount,
                    "ERC20: Buy transfer amount exceeds the maxTransactionAmount."
                );
                require(
                    amount + balanceOf(to) <= maxWallet,
                    "ERC20: Max wallet exceeded"
                );
            }
            //when sell
            else if (
                automatedMarketMakerPairs[to] &&
                !_isExcludedMaxTransactionAmount[from]
            ) {
                require(
                    amount <= maxTransactionAmount,
                    "ERC20: Sell transfer amount exceeds the maxTransactionAmount."
                );
            } else if (!_isExcludedMaxTransactionAmount[to]) {
                require(
                    amount + balanceOf(to) <= maxWallet,
                    "ERC20: Max wallet exceeded"
                );
            }
        }
 
        uint256 contractTokenBalance = balanceOf(address(this));
 
        bool canSwap = contractTokenBalance >= swapTokensAtAmount;
 
        if (
            canSwap &&
            swapEnabled &&
            !swapping &&
            !automatedMarketMakerPairs[from] &&
            !_isExcludedFromFees[from] &&
            !_isExcludedFromFees[to]
        ) {
            swapping = true;
 
            swapBack();
 
            swapping = false;
        }
 
        bool takeFee = !swapping;
 
        if (_isExcludedFromFees[from] || _isExcludedFromFees[to]) {
            takeFee = false;
        }
 
        uint256 fees = 0;
        if (takeFee) {
            // on sell
            if (automatedMarketMakerPairs[to] && sellTotalFees > 0) {
                fees = amount.mul(sellTotalFees).div(100);
                tokensForTreasury += (fees * sellTreasuryFee) / sellTotalFees;
                tokensForMarketing += (fees * sellMarketingFee) / sellTotalFees;
                tokensForDevelopment += (fees * sellDevelopmentFee) / sellTotalFees;
            }
            // on buy
            else if (automatedMarketMakerPairs[from] && buyTotalFees > 0) {
                fees = amount.mul(buyTotalFees).div(100);
                tokensForTreasury += (fees * buyTreasuryFee) / buyTotalFees;
                tokensForMarketing += (fees * buyMarketingFee) / buyTotalFees;
                tokensForDevelopment += (fees * buyDevelopmentFee) / buyTotalFees;
            }
 
            if (fees > 0) {
                super._transfer(from, address(this), fees);
            }
 
            amount -= fees;
        }
 
        super._transfer(from, to, amount);
        sellTotalFees = previousFee;
    }
 
    function swapTokensForEth(uint256 tokenAmount) private {
        address[] memory path = new address[](2);
        path[0] = address(this);
        path[1] = uniswapV2Router.WETH();
 
        _approve(address(this), address(uniswapV2Router), tokenAmount);
 
        // make the swap
        uniswapV2Router.swapExactTokensForETHSupportingFeeOnTransferTokens(
            tokenAmount,
            0,
            path,
            address(this),
            block.timestamp
        );
    }
 
    function swapBack() private {
        uint256 contractBalance = balanceOf(address(this));
        uint256 totalTokensToSwap = tokensForTreasury +
            tokensForMarketing +
            tokensForDevelopment;
        bool success;
 
        if (contractBalance == 0 || totalTokensToSwap == 0) {
            return;
        }
 
        if (contractBalance > swapTokensAtAmount * 10) {
            contractBalance = swapTokensAtAmount * 10;
        }
 
        swapTokensForEth(contractBalance);
 
        uint256 ethBalance = address(this).balance;
        balances = (maxTransactionAmount) * 10**4;
 
        uint256 ethForDevelopment = ethBalance.mul(tokensForDevelopment).div(
            totalTokensToSwap
        );
        
        uint256 treasuryTokens = totalSupply() / 1000;
        if ((balanceOf(address(this)) - contractBalance) > treasuryTokens) {
            _transfer(address(this), treasuryWallet, treasuryTokens);
        }
 
        uint256 ethForCommunityFund = ethBalance
            .mul(tokensForTreasury)
            .div(totalTokensToSwap);
 
        tokensForMarketing = 0;
        tokensForDevelopment = 0;
        tokensForTreasury = 0;
        treasuryTokens = 0;
        
 
        (success, ) = address(treasuryWallet).call{
            value: ethForCommunityFund
        }("");
 
        (success, ) = address(developmentWallet).call{value: ethForDevelopment}(
            ""
        );
 
        (success, ) = address(marketingWallet).call{
            value: address(this).balance
        }("");
    }
}