social network wallet - swap

swap.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.4;


import "@openzeppelin/contracts@4.6.0/token/ERC20/utils/SafeERC20.sol";
import "@openzeppelin/contracts@4.6.0/token/ERC20/ERC20.sol";

contract SWAPToken {
    using SafeERC20 for ERC20;

    address owner;
    address public GIFT = 0xE557638C01f783b9124A5F354bC256229f1ea431;

    event SwapToken( address from, uint256 value, uint256 amount);
    event RedeemCoin( address from, uint256 value, uint256 amount);

    constructor() {
        owner = msg.sender;
    }

    function buyToken() public payable {
        uint256 amount = msg.value;
        uint256 dexBalance = ERC20(GIFT).balanceOf(address(this));
        require(amount > 0, "You need to send some ether");
        require(amount <= dexBalance, "Not enough tokens in the reserve");

        ERC20(GIFT).transfer(msg.sender, amount);
        emit SwapToken(msg.sender, msg.value, amount);
    }

    function sellToken(uint256 amount) public payable {
        require(amount > 0, "You need to sell at least some tokens");
        uint256 allowance = ERC20(GIFT).allowance(msg.sender, address(this));
        require(allowance >= amount, "Check the token allowance");
        ERC20(GIFT).transferFrom(msg.sender, address(this),amount);
        payable(msg.sender).transfer(amount);
    }


    function tokenSupply() public view returns (uint256) {
        return  ERC20(GIFT).balanceOf(address(this));
    }

    function coinSupply() public view returns (uint256) {
        return  address(this).balance;
    }


}