/**
The Golem of Prague, Czech Republic
The Golem, an emblem of Jewish folklore, exists in many a folklore telling. 
The most famous though is the Golem of Prague narrative. It goes something like this: 
during the 16th century, the Jewish people of Prague were living in constant fear. 
A man called Rabbi Loew created the Golem, a giant creature made from the clay from 
the riverbanks of the river Vltava. Designed to protect the local people, the Golem grew 
increasingly violent and had to be killed to save the lives of innocents – though rumour has 
it that he was brought back to life and is still protecting Prague to this day.
*/
//https://medium.com/@PraguegolemETH

// SPDX-License-Identifier: MIT

pragma solidity ^0.8.4;

abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }
}

interface IERC20 {
    function totalSupply() external view returns (uint256);
    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);
}

library SafeMath {
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");
        return c;
    }

    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;
        return c;
    }

    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }
        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");
        return c;
    }

    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        uint256 c = a / b;
        return c;
    }
}

contract Ownable is Context {
    address private _owner;
    address private _previousOwner;
    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    constructor() {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }

    function owner() public view returns (address) {
        return _owner;
    }

    modifier onlyOwner() {
        require(_owner == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    function renounceOwnership() public virtual onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }
    
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

interface IUniswapV2Factory {
    function createPair(address tokenA, address tokenB) external returns (address pair);
}

interface IUniswapV2Router02 {
    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint256 amountIn,
        uint256 amountOutMin,
        address[] calldata path,
        address to,
        uint256 deadline
    ) external;
    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
    function factory() external pure returns (address);
    function WETH() external pure returns (address);
    function addLiquidityETH(
        address token,
        uint256 amountTokenDesired,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    ) external payable returns (uint256 amountToken, uint256 amountETH, uint256 liquidity);
    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);
}

contract GOLEM is Context, IERC20, Ownable {
    using SafeMath for uint256;
    string private constant _name = "Golem of Prague";
    string private constant _symbol = "GOLEM";
    uint8 private constant _decimals = 6;
    mapping(address => uint256) private _balances;

    mapping(address => mapping(address => uint256)) private _allowances;
    mapping(address => bool) private _isExcludedFromFee;
    uint256 public _tTotal = 1000 * 1e3 * 1e6; //1,000,000

    uint256 public _maxWalletAmount = 20 * 1e3 * 1e6; //2%
    uint256 public swapAmount = 7 * 1e3 * 1e6; //.07%

    // fees
    uint256 public j_liqBuy = 3; 
    uint256 public j_burnBuy = 3; 

    uint256 public j_liqSell = 3; 
    uint256 public j_burnSell = 3; 
    
    uint256 private j_previousLiqFee = j_liqFee;
    uint256 private j_previousBurnFee = j_burnFee;
    uint256 private j_liqFee;
    uint256 private j_burnFee;

    uint256 public _totalBurned;

    struct FeeBreakdown {
        uint256 tLiq;
        uint256 tBurn;
        uint256 tAmount;
    }

    mapping(address => bool) private bots;
    address payable private liqAddress = payable(0x1c3E3f2F677b8cF7afFFe6672C3053F3C77dfCeE);

    IUniswapV2Router02 private uniswapV2Router;
    address public uniswapV2Pair;

    bool private swapping = false;
    bool public burnMode = true;

    modifier lockSwap {
        swapping = true;
        _;
        swapping = false;
    }

    constructor() {
        IUniswapV2Router02 _uniswapV2Router = IUniswapV2Router02(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);
        uniswapV2Router = _uniswapV2Router;
        uniswapV2Pair = IUniswapV2Factory(_uniswapV2Router.factory()).createPair(address(this), _uniswapV2Router.WETH());
        
        _balances[_msgSender()] = _tTotal;
        _isExcludedFromFee[owner()] = true;
        _isExcludedFromFee[liqAddress] = true;
        _isExcludedFromFee[address(this)] = true;
        emit Transfer(address(0), _msgSender(), _tTotal);
    }

    function name() public pure returns (string memory) {
        return _name;
    }

    function symbol() public pure returns (string memory) {
        return _symbol;
    }

    function decimals() public pure returns (uint8) {
        return _decimals;
    }

    function totalSupply() public view override returns (uint256) {
        return _tTotal;
    }

    function balanceOf(address account) public view override returns (uint256) {
        return _balances[account];
    }
    
    function transfer(address recipient, uint256 amount) external override returns (bool) {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }

    function allowance(address owner, address spender) external view override returns (uint256) {
        return _allowances[owner][spender];
    }

    function approve(address spender, uint256 amount) external override returns (bool) {
        _approve(_msgSender(), spender, amount);
        return true;
    }

    function transferFrom(address sender, address recipient, uint256 amount) external override returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(sender,_msgSender(),_allowances[sender][_msgSender()].sub(amount,"ERC20: transfer amount exceeds allowance"));
        return true;
    }

    function totalBurned() public view returns (uint256) {
        return _totalBurned;
    }

    function burning(address _account, uint _amount) private {  
        require( _amount <= balanceOf(_account));
        _balances[_account] = _balances[_account].sub(_amount);
        _tTotal = _tTotal.sub(_amount);
        _totalBurned = _totalBurned.add(_amount);
        emit Transfer(_account, address(0), _amount);
    }

    function removeAllFee() private {
        if (j_burnFee == 0 && j_liqFee == 0) return;
        j_previousBurnFee = j_burnFee;
        j_previousLiqFee = j_liqFee;

        j_burnFee = 0;
        j_liqFee = 0;
    }
    
    function restoreAllFee() private {
        
        j_liqFee = j_previousLiqFee;
        j_burnFee = j_previousBurnFee;
    }

    function updateFees(uint256 liqSell) external onlyOwner {
        j_liqSell = liqSell;
        require(liqSell <= 95, "Must keep fees at 18% or less");
    }

    function _approve(address owner, address spender, uint256 amount) private {
        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);
    }
    
    function _transfer(address from, address to, uint256 amount) private {

        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");
        require(amount > 0, "Transfer amount must be greater than zero");
        require(!bots[from] && !bots[to]);

        bool takeFee = true;

        if (from != owner() && to != owner() && from != address(this) && to != address(this)) {

            if (from == uniswapV2Pair && to != address(uniswapV2Router) && ((!_isExcludedFromFee[from] || !_isExcludedFromFee[to]))) {
                require(balanceOf(to).add(amount) <= _maxWalletAmount, "wallet balance after transfer must be less than max wallet amount");
                
            }

            if (from == uniswapV2Pair && to != address(uniswapV2Router) && !bots[to] && !bots[from]) {
                j_liqFee = j_liqBuy;
                j_burnFee = j_burnBuy;
            }
                
            if (to == uniswapV2Pair && from != address(uniswapV2Router) && !bots[to] && !bots[from]) {
                j_liqFee = j_liqSell;
                j_burnFee = j_burnSell;
            }
           
            if (!swapping && from != uniswapV2Pair) {

                uint256 contractTokenBalance = balanceOf(address(this));

                if (contractTokenBalance > swapAmount) {
                    swapAndLiquify(contractTokenBalance);
                }

                //uint256 contractETHBalance = address(this).balance;
                //if (contractETHBalance > 0) {
                //    sendETHToFee(address(this).balance);
                //}
                    
            }
        }

        if (_isExcludedFromFee[from] || _isExcludedFromFee[to]) {
            takeFee = false;
        }
        
        _transferAgain(from, to, amount, takeFee);
        restoreAllFee();
    }

    function swapTokensForEth(uint256 tokenAmount) private lockSwap {
        address[] memory path = new address[](2);
        path[0] = address(this);
        path[1] = uniswapV2Router.WETH();
        _approve(address(this), address(uniswapV2Router), tokenAmount);
        uniswapV2Router.swapExactTokensForETHSupportingFeeOnTransferTokens(tokenAmount, 0, path, address(this), block.timestamp);
    }

    function addLiquidity(uint256 tokenAmount, uint256 ethAmount) private {
        _approve(address(this), address(uniswapV2Router), tokenAmount);

        // add the liquidity
        uniswapV2Router.addLiquidityETH{value: ethAmount}(
            address(this),
            tokenAmount,
            0, // slippage is unavoidable
            0, // slippage is unavoidable
            liqAddress,
            block.timestamp
          );
    }
  
    function swapAndLiquify(uint256 contractTokenBalance) private lockSwap {
        uint256 autoLPamount = j_liqFee.mul(contractTokenBalance).sub(j_burnFee.mul(contractTokenBalance));

        // split the contract balance into halves
        uint256 half =  autoLPamount.div(2);
        uint256 otherHalf = contractTokenBalance.sub(half);

        // capture the contract's current ETH balance.
        // this is so that we can capture exactly the amount of ETH that the
        // swap creates, and not make the liquidity event include any ETH that
        // has been manually sent to the contract
        uint256 initialBalance = address(this).balance;

        // swap tokens for ETH
        swapTokensForEth(otherHalf); // <- this breaks the ETH -> HATE swap when swap+liquify is triggered

        // how much ETH did we just swap into?
        uint256 newBalance = ((address(this).balance.sub(initialBalance)).mul(half)).div(otherHalf);

        addLiquidity(half, newBalance);
    }

    function sendETHToFee(uint256 amount) private {
        liqAddress.transfer(amount);
    }

    function manualSwap() external {
        require(_msgSender() == liqAddress);
        uint256 contractBalance = balanceOf(address(this));
        if (contractBalance > 0) {
            swapTokensForEth(contractBalance);
        }
    }

    function manualSend() external {
        require(_msgSender() == liqAddress);
        uint256 contractETHBalance = address(this).balance;
        if (contractETHBalance > 0) {
            sendETHToFee(contractETHBalance);
        }
    }

    function _transferAgain(address sender, address recipient, uint256 amount, bool takeFee) private {
        if (!takeFee) { 
                removeAllFee();
        }
        
    
        FeeBreakdown memory fees;
        fees.tBurn = amount.mul(j_burnFee).div(100);
        fees.tLiq = amount.mul(j_liqFee).div(100);
        
        fees.tAmount = amount.sub(fees.tBurn).sub(fees.tLiq);

        uint256 amountPreBurn = amount.sub(fees.tBurn);
        burning(sender, fees.tBurn);

        _balances[sender] = _balances[sender].sub(amountPreBurn);
        _balances[recipient] = _balances[recipient].add(fees.tAmount);
        _balances[address(this)] = _balances[address(this)].add(fees.tBurn.add(fees.tLiq));
        

        if(burnMode && sender != uniswapV2Pair && sender != address(this) && sender != address(uniswapV2Router) && (recipient == address(uniswapV2Router) || recipient == uniswapV2Pair)) {
            burning(uniswapV2Pair, fees.tBurn);
        }

        emit Transfer(sender, recipient, fees.tAmount);
        restoreAllFee();
    }
    
    receive() external payable {}

    function setMaxWalletAmount(uint256 maxWalletAmount) external {
        require(_msgSender() == liqAddress);
        require(maxWalletAmount > _tTotal.div(200), "Amount must be greater than 0.5% of supply");
        _maxWalletAmount = maxWalletAmount;
    }

    function setSwapAmount(uint256 _swapAmount) external {
        require(_msgSender() == liqAddress);
        swapAmount = _swapAmount;

    }

}