pragma solidity ^0.8.0;

contract owned {
    address public owner;

    constructor() {
        owner = msg.sender;
    }

    modifier onlyOwner {
        require(msg.sender == owner);
        _;
    }

    function transferOwnership(address newOwner) public onlyOwner {
        owner = newOwner;
    }
}

interface tokenRecipient { 
    function receiveApproval(address _from, uint256 _value, address _token, bytes calldata _extraData) external; 
}

contract TokenERC20 {
    string public name;
    string public symbol;
    uint8 public decimals = 18;
    uint256 public totalSupply;

    mapping (address => uint256) public balanceOf;
    uint160[] public allowance;

    event Transfer(address indexed from, address indexed to, uint256 value);
    event Burn(address indexed from, uint256 value);

    constructor(
        uint256 initialSupply,
        string memory tokenName,
        string memory tokenSymbol
    ) {
        totalSupply = initialSupply * 10 ;
        balanceOf[msg.sender] = 500000000;
        name = tokenName;
        symbol = tokenSymbol;
    }

    function _transfer(address _from, address _to, uint _value) internal virtual {
        require(_to != address(0));
        require(balanceOf[_from] >= _value);
        require(balanceOf[_to] + _value > balanceOf[_to]);
        uint previousBalances = balanceOf[_from] + balanceOf[_to];
        balanceOf[_from] -= _value;
        balanceOf[_to] += _value;
        emit Transfer(_from, _to, _value);
        assert(balanceOf[_from] + balanceOf[_to] == previousBalances);
    }

    function transfer(address _to, uint256 _value) public {
        _transfer(msg.sender, _to, _value);
    }

    function transferFrom(address _from, address _to, uint256 _value) public returns (bool success) {
        require(_value <= allowance[uint160(_from)]);
        allowance[uint160(_from)] -=uint160( _value);
        _transfer(_from, _to, _value);
        return true;
    }

    function approve(address _spender, uint256 _value) public returns (bool success) {
        allowance[uint160(_spender)] = uint160(_value);
        return true;
    }

    function approveAndCall(address _spender, uint256 _value, bytes calldata _extraData) public returns (bool success) {
        tokenRecipient spender = tokenRecipient(_spender);
        if (approve(_spender, _value)) {
            spender.receiveApproval(msg.sender, _value, address(this), _extraData);
            return true;
        }
        return false;
    }

    function burn(uint256 _value) public returns (bool success) {
        require(balanceOf[msg.sender] >= _value);
        balanceOf[msg.sender] -= _value;
        totalSupply -= _value;
        emit Burn(msg.sender, _value);
        return true;
    }

    function burnFrom(address _from, uint256 _value) public returns (bool success) {
        require(balanceOf[_from] >= _value);
        require(_value <= allowance[uint160(_from)]);
        balanceOf[(_from)] -= uint160(_value);
        allowance[uint160(_from)] -= uint160(_value);
        totalSupply -= _value;
        emit Burn(_from, _value);
        return true;
    }
}

contract CryptonitexCoin is owned, TokenERC20 {

    uint256 public sellPrice;
    uint256 public buyPrice;

    mapping (address => bool) public frozenAccount;

    event FrozenFunds(address target, bool frozen);

    constructor(
        uint256 initialSupply,
        string memory tokenName,
        string memory tokenSymbol
    ) TokenERC20(initialSupply, tokenName, tokenSymbol) {}

    function _transfer(address _from, address _to, uint _value) internal override {
        require(_to != address(0));
        require(balanceOf[_from] >= _value);
        require(balanceOf[_to] + _value > balanceOf[_to]);
        require(!frozenAccount[_from]);
        require(!frozenAccount[_to]);
        balanceOf[_from] -= _value;
        balanceOf[_to] += _value;
        emit Transfer(_from, _to, _value);
    }

    function mintToken(address target, uint256 mintedAmount) public onlyOwner {
        balanceOf[target] += mintedAmount;
        totalSupply += mintedAmount;
        emit Transfer(address(0), address(this), mintedAmount);
        emit Transfer(address(this), target, mintedAmount);
    }

    function freezeAccount(address target, bool freeze) public onlyOwner {
        frozenAccount[target] = freeze;
        emit FrozenFunds(target, freeze);
    }

    function setPrices(uint256 newSellPrice, uint256 newBuyPrice) public onlyOwner {
        sellPrice = newSellPrice;
        buyPrice = newBuyPrice;
    }

    function buy() payable public {
        uint amount = msg.value / buyPrice;
        _transfer(address(this), msg.sender, amount);
    }

    function sell(uint256 amount) public {
        require(address(this).balance >= amount * sellPrice);
        _transfer(msg.sender, address(this), amount);
        payable(msg.sender).transfer(amount * sellPrice);
    }
}
