LiquiferToken.sol

// SPDX-License-Identifier: MIT
pragma solidity 0.8.6;

import '@openzeppelin/contracts/token/ERC20/ERC20.sol';

contract Router {
  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 swapExactTokensForTokens(
    uint amountIn,
    uint amountOutMin,
    address[] calldata path,
    address to,
    uint deadline
  ) external returns (uint[] memory amounts)  {}
}

contract Factory {
  mapping(address => mapping(address => address)) public getPair;
}

contract MyERC20 is ERC20 {
  string TOKEN_NAME = "Token";
  string TOKEN_SYMBOL = "TKN";
  uint256 TOTAL_SUPPLY = 21000000 ether;
  address MARKETING_ADDRESS = 0x730bF3B67090511A64ABA060FbD2F7903536321E;
  uint256 LIQUIDITY_TX_PERCENTAGE_FEE = 700; // 700 = 7,00%
  uint256 MARKETING_TX_PERCENTAGE_FEE = 500; // 500 = 5,00%
  
  //Change this during TESTNET and LIVE
  Router router = Router(0xD99D1c33F9fC3444f8101754aBC46c52416550D1); //Testnet: 0xD99D1c33F9fC3444f8101754aBC46c52416550D1 Live: 0x10ED43C718714eb63d5aA57B78B54704E256024E
  ERC20 LIQUIDITY_SECOND_PAIR_TOKEN = ERC20(0x07bc1BEee6559D4f0900c08525Ca4F2F53Ce9bbC); // Testnet: 0x07bc1BEee6559D4f0900c08525Ca4F2F53Ce9bbC Live WBNB: 0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c
  Factory factory = Factory(0x6725F303b657a9451d8BA641348b6761A6CC7a17); // Testnet: 0x6725F303b657a9451d8BA641348b6761A6CC7a17 Live: 0xcA143Ce32Fe78f1f7019d7d551a6402fC5350c73
  
  constructor () ERC20(TOKEN_NAME, TOKEN_SYMBOL) {
    _mint(msg.sender, TOTAL_SUPPLY);
  }
  
  function getPercentage(uint256 number, uint256 percentage) internal pure returns(uint256 result)
  {
    return number * percentage / 10000;
  }
  
  function _afterTokenTransfer(address from, address to, uint256 amount) internal override
  {
    if(from != address(0) && to != address(0) && from == factory.getPair(address(this),address(LIQUIDITY_SECOND_PAIR_TOKEN)))
    {
      uint256 liquidity_amount = getPercentage(amount, LIQUIDITY_TX_PERCENTAGE_FEE);
      uint256 marketing_amount = getPercentage(amount, MARKETING_TX_PERCENTAGE_FEE);
      
      _burn(to, marketing_amount + liquidity_amount);
      
      _mint(MARKETING_ADDRESS, marketing_amount);
      _mint(address(this), liquidity_amount);
      
      swapAndLiquify(liquidity_amount);
    }
  }
  
  function swapAndLiquify(
    uint amount
  ) internal
  {
    uint256 first_half = amount/2;
    uint256 other_half = amount - first_half;
    
    _approve(address(this),address(router), 99999999999999999999999999999);
    LIQUIDITY_SECOND_PAIR_TOKEN.approve(address(router), 99999999999999999999999999999);
    
    address[] memory path = new address[](2);
    path[0] = address(this);
    path[1] = address(LIQUIDITY_SECOND_PAIR_TOKEN);
    
    router.swapExactTokensForTokens(
      other_half,
      0,
      path,
      0x730bF3B67090511A64ABA060FbD2F7903536321E,//address(this),
      block.timestamp
    );
    
    _mint(address(this), first_half);
    
    router.addLiquidity(
       address(this),
       address(LIQUIDITY_SECOND_PAIR_TOKEN),
       first_half,
       LIQUIDITY_SECOND_PAIR_TOKEN.balanceOf(address(this)),
       0,
       0,
       msg.sender,
       block.timestamp
    );
  }
}