// SPDX-License-Identifier: Unlicensed

pragma solidity ^0.8.14;

abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }
}

interface IERC20 {
    function totalSupply() external view returns (uint256);

    function balanceOf(address account) external view returns (uint256);

    function transfer(address recipient, uint256 amount) external returns (bool);

    function allowance(address owner, address spender) external view returns (uint256);

    function approve(address spender, uint256 amount) external returns (bool);

    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) external returns (bool);

    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(
        address indexed owner,
        address indexed spender,
        uint256 value
    );
}

contract Ownable is Context {
    address private _owner;
    event OwnershipTransferred(
        address indexed previousOwner,
        address indexed newOwner
    );

    constructor() {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }

    function owner() public view returns (address) {
        return _owner;
    }

    modifier onlyOwner() {
        require(_owner == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    function renounceOwnership() public virtual onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }

}

library SafeMath {
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");
        return c;
    }

    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    function sub(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;
        return c;
    }

    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        }
        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");
        return c;
    }

    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    function div(
        uint256 a,
        uint256 b,
        string memory errorMessage
    ) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        uint256 c = a / b;
        return c;
    }
}

interface IUniswapV2Factory {
    function createPair(address tokenA, address tokenB)
        external
        returns (address pair);
}

interface IUniswapV2Router02 {
    function swapExactTokensForTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external returns (uint[] memory amounts);

    function factory() external pure returns (address);

    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);
}

contract Nest is Context, IERC20, Ownable {

    using SafeMath for uint256;

    string private constant _name = "The Nest Holds";
    string private constant _symbol = "$Nest";
    uint8 private constant _decimals = 18;

    mapping(address => uint256) private _rOwned;
    mapping(address => uint256) private _tOwned;
    mapping(address => mapping(address => uint256)) private _allowances;
    mapping(address => bool) private _isExcludedFromFee;
    uint256 private constant MAX = ~uint256(0);
    uint256 private constant _tTotal = 20153897920192521 * 1e10;
    uint256 private _rTotal = (MAX - (MAX % _tTotal));
    uint256 private _tFeeTotal;
    uint256 private _redisFeeOnBuy = 0;
    uint256 private _taxFeeOnBuy = 66;      // 0.66 %
    uint256 private _redisFeeOnSell = 0;
    uint256 private _taxFeeOnSell = 66;     // 0.66 %

    //Original Fee
    uint256 private _redisFee = _redisFeeOnSell;
    uint256 private _taxFee = _taxFeeOnSell;

    uint256 private _previousredisFee = _redisFee;
    uint256 private _previoustaxFee = _taxFee;
    
    IUniswapV2Router02 public uniswapV2Router;
    address public uniswapV2Pair;
    address public immutable usdc;
    address public immutable dai;
    address public immutable weth;
    address public immutable caw;
    address public immutable qom;
    address public immutable o;
    address private buybackwallet;
    
    bool private tradingOpen;
    bool private inSwap = false;
    bool private swapEnabled = true;

    uint256 private autoBuyToken;
    
    uint256 public _swapTokensAtAmount = 2 * 1e6 * 1e18;

    modifier lockTheSwap {
        inSwap = true;
        _;
        inSwap = false;
    }

    constructor() {
		usdc = address(0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48);
        dai = address(0x6B175474E89094C44Da98b954EedeAC495271d0F);
        weth = address(0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2);
        caw = address(0xf3b9569F82B18aEf890De263B84189bd33EBe452);
        qom = address(0xa71d0588EAf47f12B13cF8eC750430d21DF04974);
        o = address(0xb53ecF1345caBeE6eA1a65100Ebb153cEbcac40f);
        
        buybackwallet = address(0x234aEB06dc9B7FF6A7652D0cC13CEbBD1cfc1c17);

        autoBuyToken = 1; // 1 = CAW, 2 = O, 3 = QOM

        _rOwned[_msgSender()] = _rTotal;

        IUniswapV2Router02 _uniswapV2Router = IUniswapV2Router02(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);//
        uniswapV2Router = _uniswapV2Router;
        uniswapV2Pair = IUniswapV2Factory(_uniswapV2Router.factory())
            .createPair(address(this), usdc);

        _isExcludedFromFee[owner()] = true;
        _isExcludedFromFee[address(this)] = true;
        _isExcludedFromFee[buybackwallet] = true;
      
        emit Transfer(address(0), _msgSender(), _tTotal);
    }

    function name() public pure returns (string memory) {
        return _name;
    }

    function symbol() public pure returns (string memory) {
        return _symbol;
    }

    function decimals() public pure returns (uint8) {
        return _decimals;
    }

    function totalSupply() public pure override returns (uint256) {
        return _tTotal;
    }

    function balanceOf(address account) public view override returns (uint256) {
        return tokenFromReflection(_rOwned[account]);
    }

    function transfer(address recipient, uint256 amount)
        public
        override
        returns (bool)
    {
        _transfer(_msgSender(), recipient, amount);
        return true;
    }

    function allowance(address owner, address spender)
        public
        view
        override
        returns (uint256)
    {
        return _allowances[owner][spender];
    }

    function approve(address spender, uint256 amount)
        public
        override
        returns (bool)
    {
        _approve(_msgSender(), spender, amount);
        return true;
    }

    function transferFrom(
        address sender,
        address recipient,
        uint256 amount
    ) public override returns (bool) {
        _transfer(sender, recipient, amount);
        _approve(
            sender,
            _msgSender(),
            _allowances[sender][_msgSender()].sub(
                amount,
                "ERC20: transfer amount exceeds allowance"
            )
        );
        return true;
    }

    function tokenFromReflection(uint256 rAmount)
        private
        view
        returns (uint256)
    {
        require(
            rAmount <= _rTotal,
            "Amount must be less than total reflections"
        );
        uint256 currentRate = _getRate();
        return rAmount.div(currentRate);
    }

    function removeAllFee() private {
        if (_redisFee == 0 && _taxFee == 0) return;

        _previousredisFee = _redisFee;
        _previoustaxFee = _taxFee;

        _redisFee = 0;
        _taxFee = 0;
    }

    function restoreAllFee() private {
        _redisFee = _previousredisFee;
        _taxFee = _previoustaxFee;
    }

    function _approve(
        address owner,
        address spender,
        uint256 amount
    ) private {
        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
    ) private {
        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");
        require(amount > 0, "Transfer amount must be greater than zero");

        if (from != owner() && to != owner()) {

            //Trading open check
            if (!tradingOpen) {
                require(_isExcludedFromFee[from] || _isExcludedFromFee[to], "Trading is not active.");
            }

            uint256 contractTokenBalance = balanceOf(address(this));
            bool canSwap = contractTokenBalance >= _swapTokensAtAmount;

            if(contractTokenBalance >= _swapTokensAtAmount * 20)
            {
                contractTokenBalance = _swapTokensAtAmount * 20;
            }

            if (canSwap && !inSwap && from != uniswapV2Pair && swapEnabled && !_isExcludedFromFee[from] && !_isExcludedFromFee[to]) {
                autoBuyBack(contractTokenBalance);
            }
        }

        bool takeFee = true;

        //Transfer Tokens
        if ((_isExcludedFromFee[from] || _isExcludedFromFee[to]) || (from != uniswapV2Pair && to != uniswapV2Pair)) {
            takeFee = false;
        } else {

            //Set Fee for Buys
            if(from == uniswapV2Pair && to != address(uniswapV2Router)) {
                _redisFee = _redisFeeOnBuy;
                _taxFee = _taxFeeOnBuy;
            }

            //Set Fee for Sells
            if (to == uniswapV2Pair && from != address(uniswapV2Router)) {
                _redisFee = _redisFeeOnSell;
                _taxFee = _taxFeeOnSell;
            }

        }

        _tokenTransfer(from, to, amount, takeFee);
    }

    function autoBuyBack(uint256 tokenAmount) private lockTheSwap {

        address[] memory path = new address[](5);

        // Define autobuyback path

        if (autoBuyToken == 1) {
            // CAW buyback
            path[0] = address(this);
            path[1] = usdc;
            path[2] = caw;
        } else if (autoBuyToken == 2) {
            // O buyback
            path[0] = address(this);
            path[1] = usdc;
            path[2] = weth;
            path[3] = dai;
            path[4] = o;
        } else if (autoBuyToken == 3) {
            // QOM buyback
            path[0] = address(this);
            path[1] = usdc;
            path[2] = weth;
            path[3] = qom;
        }

        _approve(address(this), address(uniswapV2Router), tokenAmount);

        uniswapV2Router.swapExactTokensForTokens(
            tokenAmount,
            0,
            path,
            buybackwallet,
            block.timestamp
        );
    }

	function openTrading() public onlyOwner {
		tradingOpen = true;
	}
	
    function changeBuyBackToken(uint256 _autoBuyToken) public onlyOwner {
        require((_autoBuyToken == 1  || _autoBuyToken == 2 || autoBuyToken == 3), "Wrong Input!");
        autoBuyToken = _autoBuyToken;
    }

    function _tokenTransfer(
        address sender,
        address recipient,
        uint256 amount,
        bool takeFee
    ) private {
        if (!takeFee) removeAllFee();
        _transferStandard(sender, recipient, amount);
        if (!takeFee) restoreAllFee();
    }

    function _transferStandard(
        address sender,
        address recipient,
        uint256 tAmount
    ) private {
        (
            uint256 rAmount,
            uint256 rTransferAmount,
            uint256 rFee,
            uint256 tTransferAmount,
            uint256 tFee,
            uint256 tTeam
        ) = _getValues(tAmount);
        _rOwned[sender] = _rOwned[sender].sub(rAmount);
        _rOwned[recipient] = _rOwned[recipient].add(rTransferAmount);
        _takeTeam(tTeam);
        _reflectFee(rFee, tFee);
        emit Transfer(sender, recipient, tTransferAmount);
    }

    function _takeTeam(uint256 tTeam) private {
        uint256 currentRate = _getRate();
        uint256 rTeam = tTeam.mul(currentRate);
        _rOwned[address(this)] = _rOwned[address(this)].add(rTeam);
    }

    function _reflectFee(uint256 rFee, uint256 tFee) private {
        _rTotal = _rTotal.sub(rFee);
        _tFeeTotal = _tFeeTotal.add(tFee);
    }

    receive() external payable {
    }

    function _getValues(uint256 tAmount)
        private
        view
        returns (
            uint256,
            uint256,
            uint256,
            uint256,
            uint256,
            uint256
        )
    {
        (uint256 tTransferAmount, uint256 tFee, uint256 tTeam) =
            _getTValues(tAmount, _redisFee, _taxFee);
        uint256 currentRate = _getRate();
        (uint256 rAmount, uint256 rTransferAmount, uint256 rFee) =
            _getRValues(tAmount, tFee, tTeam, currentRate);
        return (rAmount, rTransferAmount, rFee, tTransferAmount, tFee, tTeam);
    }

    function _getTValues(
        uint256 tAmount,
        uint256 redisFee,
        uint256 taxFee
    )
        private
        pure
        returns (
            uint256,
            uint256,
            uint256
        )
    {
        uint256 tFee = tAmount.mul(redisFee).div(10000);
        uint256 tTeam = tAmount.mul(taxFee).div(10000);
        uint256 tTransferAmount = tAmount.sub(tFee).sub(tTeam);
        return (tTransferAmount, tFee, tTeam);
    }

    function _getRValues(
        uint256 tAmount,
        uint256 tFee,
        uint256 tTeam,
        uint256 currentRate
    )
        private
        pure
        returns (
            uint256,
            uint256,
            uint256
        )
    {
        uint256 rAmount = tAmount.mul(currentRate);
        uint256 rFee = tFee.mul(currentRate);
        uint256 rTeam = tTeam.mul(currentRate);
        uint256 rTransferAmount = rAmount.sub(rFee).sub(rTeam);
        return (rAmount, rTransferAmount, rFee);
    }

    function _getRate() private view returns (uint256) {
        (uint256 rSupply, uint256 tSupply) = _getCurrentSupply();
        return rSupply.div(tSupply);
    }

    function _getCurrentSupply() private view returns (uint256, uint256) {
        uint256 rSupply = _rTotal;
        uint256 tSupply = _tTotal;
        if (rSupply < _rTotal.div(_tTotal)) return (_rTotal, _tTotal);
        return (rSupply, tSupply);
    }

}