// SPDX-License-Identifier: MIT

pragma solidity >=0.6.0 <0.8.0;

import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v3.3.0/contracts/token/ERC20/ERC20.sol";
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v3.3.0/contracts/token/ERC20/SafeERC20.sol";
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/v3.3.0/contracts/payment/PaymentSplitter.sol";

contract TechTok is ERC20{
    
    using SafeMath for uint256;
    
    constructor() ERC20('TechTok', 'TEKT'){
        _setupDecimals(6);
        _mint(msg.sender, 20000000000);
    }
}

contract DEX{
    
    event Bought(uint256 amount);
    event Sold(uint256 amount);

    address private owner;
    ERC20 private token;
    // mapping(ERC20Detailed => uint64) tokens;
    uint64 private exchange;

    constructor() {
        owner = 0x5B38Da6a701c568545dCfcB03FcB875f56beddC4;
        token = ERC20(0x358AA13c52544ECCEF6B0ADD0f801012ADAD5eE3);
        exchange = 500;
    }
    
    function buy() payable public {
        uint256 amountTobuy = msg.value;
        uint256 dexBalance = token.balanceOf(address(this));
        require(amountTobuy > 0, "You need to send some Ether");
        require(amountTobuy <= dexBalance, "Not enough tokens in the reserve");
        // token.approve(address(this), amountTobuy);
        token.transfer(msg.sender, amountTobuy);
        emit Bought(amountTobuy);
    }
    
    function sell(uint256 amount) public {
        require(amount > 0, "You need to sell at least some tokens");
        uint256 allowance = token.allowance(msg.sender, address(this));
        require(allowance >= amount, "Check the token allowance");
        token.transferFrom(msg.sender, address(this), amount);
        msg.sender.transfer(amount);
        emit Sold(amount);
    }
    
    function getBalance() public view returns(uint){
        return token.balanceOf(0x5B38Da6a701c568545dCfcB03FcB875f56beddC4);
    }
    
    function getAddress() public view returns(address){
        return msg.sender;
    }
    
    function getThisAddress() public view returns (address){
        return address(this);
    }

}

{
  "compilationTarget": {
    "browser/Example.sol": "TechTok"
  },
  "evmVersion": "istanbul",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs"
  },
  "optimizer": {
    "enabled": false,
    "runs": 200
  },
  "remappings": []
}