/** SPDX-License-Identifier: MIT

$$$$$$$\  $$$$$$$$\ $$$$$$$\  $$\   $$\  $$$$$$\  $$\   $$\ $$$$$$\ $$$$$$$\  $$$$$$$$\ 
$$  __$$\ $$  _____|$$  __$$\ $$ | $$  |$$  __$$\ $$ |  $$ |\_$$  _|$$  __$$\ $$  _____|
$$ |  $$ |$$ |      $$ |  $$ |$$ |$$  / $$ /  \__|$$ |  $$ |  $$ |  $$ |  $$ |$$ |      
$$$$$$$\ |$$$$$\    $$$$$$$  |$$$$$  /  \$$$$$$\  $$$$$$$$ |  $$ |  $$$$$$$  |$$$$$\    
$$  __$$\ $$  __|   $$  __$$< $$  $$<    \____$$\ $$  __$$ |  $$ |  $$  __$$< $$  __|   
$$ |  $$ |$$ |      $$ |  $$ |$$ |\$$\  $$\   $$ |$$ |  $$ |  $$ |  $$ |  $$ |$$ |      
$$$$$$$  |$$$$$$$$\ $$ |  $$ |$$ | \$$\ \$$$$$$  |$$ |  $$ |$$$$$$\ $$ |  $$ |$$$$$$$$\ 
\_______/ \________|\__|  \__|\__|  \__| \______/ \__|  \__|\______|\__|  \__|\________|

Berkshire Hathaway (BRK) -> https://brk.fund/
*/

pragma solidity ^0.8.17;

/**
 * OpenZeppelin Contracts v4.4.1 (utils/Context.sol)
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

/**
 * OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)
 */
interface IERC20 {
    event Transfer(address indexed from, address indexed to, uint256 value);

    event Approval(
        address indexed owner,
        address indexed spender,
        uint256 value
    );

    function totalSupply() external view returns (uint256);

    function balanceOf(address account) external view returns (uint256);

    function transfer(address to, 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 from,
        address to,
        uint256 amount
    ) external returns (bool);
}

/**
 * OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)
 * _Available since v4.1._
 */
interface IERC20Metadata is IERC20 {
    function name() external view returns (string memory);

    function symbol() external view returns (string memory);

    function decimals() external view returns (uint8);
}

/**
 * OpenZeppelin Contracts (last updated v4.8.0) (token/ERC20/ERC20.sol)
 */
contract ERC20 is Context, IERC20, IERC20Metadata {
    mapping(address => uint256) private _balances;

    mapping(address => mapping(address => uint256)) private _allowances;

    uint256 private _totalSupply;

    string private _name;
    string private _symbol;

    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    function name() public view virtual override returns (string memory) {
        return _name;
    }

    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    function decimals() public view virtual override returns (uint8) {
        return 18;
    }

    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }

    function balanceOf(
        address account
    ) public view virtual override returns (uint256) {
        return _balances[account];
    }

    function transfer(
        address to,
        uint256 amount
    ) public virtual override returns (bool) {
        address owner = _msgSender();
        _transfer(owner, to, amount);
        return true;
    }

    function allowance(
        address owner,
        address spender
    ) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }

    function approve(
        address spender,
        uint256 amount
    ) public virtual override returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, amount);
        return true;
    }

    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) public virtual override returns (bool) {
        address spender = _msgSender();
        _spendAllowance(from, spender, amount);
        _transfer(from, to, amount);
        return true;
    }

    function increaseAllowance(
        address spender,
        uint256 addedValue
    ) public virtual returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, allowance(owner, spender) + addedValue);
        return true;
    }

    function decreaseAllowance(
        address spender,
        uint256 subtractedValue
    ) public virtual returns (bool) {
        address owner = _msgSender();
        uint256 currentAllowance = allowance(owner, spender);
        require(
            currentAllowance >= subtractedValue,
            "ERC20: decreased allowance below zero"
        );
        unchecked {
            _approve(owner, spender, currentAllowance - subtractedValue);
        }

        return true;
    }

    function _transfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {
        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");

        _beforeTokenTransfer(from, to, amount);

        uint256 fromBalance = _balances[from];
        require(
            fromBalance >= amount,
            "ERC20: transfer amount exceeds balance"
        );
        unchecked {
            _balances[from] = fromBalance - amount;
            _balances[to] += amount;
        }

        emit Transfer(from, to, amount);

        _afterTokenTransfer(from, to, amount);
    }

    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to the zero address");

        _beforeTokenTransfer(address(0), account, amount);

        _totalSupply += amount;
        unchecked {
            _balances[account] += amount;
        }
        emit Transfer(address(0), account, amount);

        _afterTokenTransfer(address(0), account, amount);
    }

    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from the zero address");

        _beforeTokenTransfer(account, address(0), amount);

        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, "ERC20: burn amount exceeds balance");
        unchecked {
            _balances[account] = accountBalance - amount;
            _totalSupply -= amount;
        }

        emit Transfer(account, address(0), amount);

        _afterTokenTransfer(account, address(0), amount);
    }

    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 _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"
            );
            unchecked {
                _approve(owner, spender, currentAllowance - amount);
            }
        }
    }

    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}

    function _afterTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}
}

/**
 * OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(
        address indexed previousOwner,
        address indexed newOwner
    );

    constructor() {
        _transferOwnership(_msgSender());
    }

    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    function owner() public view virtual returns (address) {
        return _owner;
    }

    function _checkOwner() internal view virtual {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(
            newOwner != address(0),
            "Ownable: new owner is the zero address"
        );
        _transferOwnership(newOwner);
    }

    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

interface IDexRouter {
    function factory() external pure returns (address);

    function WETH() external pure returns (address);

    function swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;

    function swapExactETHForTokensSupportingFeeOnTransferTokens(
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external payable;

    function addLiquidityETH(
        address token,
        uint256 amountTokenDesired,
        uint256 amountTokenMin,
        uint256 amountETHMin,
        address to,
        uint256 deadline
    )
        external
        payable
        returns (uint256 amountToken, uint256 amountETH, uint256 liquidity);
}

interface IDexFactory {
    function createPair(
        address tokenA,
        address tokenB
    ) external returns (address pair);
}

contract BerkshireHathaway is ERC20, Ownable {
    uint256 public maxBuyAmount;
    uint256 public maxSellAmount;
    uint256 public maxWalletAmount;

    IDexRouter public dexRouter;
    address public lpPair;

    bool private swapping;
    uint256 public swapTokensAtAmount;

    address taxAddress;

    uint256 public tradingActiveBlock = 0;
    uint256 public blockForPenaltyEnd;
    mapping(address => bool) public boughtEarly;
    uint256 public botsCaught;

    bool public limitsInEffect = true;
    bool public tradingActive = false;
    bool public swapEnabled = false;
    bool public swapToEth = true;

    mapping(address => uint256) private _holderLastTransferTimestamp;
    bool public transferDelayEnabled = true;

    uint256 public buyTotalFees;
    uint256 public buyTaxFee;

    uint256 public sellTotalFees;
    uint256 public sellTaxFee;

    uint256 public tokensForTax;

    mapping(address => bool) private _isExcludedFromFees;
    mapping(address => bool) public _isExcludedMaxTransactionAmount;
    mapping(address => bool) public automatedMarketMakerPairs;

    event SetAutomatedMarketMakerPair(address indexed pair, bool indexed value);

    event EnabledTrading();

    event RemovedLimits();

    event ExcludeFromFees(address indexed account, bool isExcluded);

    event UpdatedMaxBuyAmount(uint256 newAmount);

    event UpdatedMaxSellAmount(uint256 newAmount);

    event UpdatedMaxWalletAmount(uint256 newAmount);

    event MaxTransactionExclusion(address _address, bool excluded);

    event OwnerForcedSwapBack(uint256 timestamp);

    event CaughtEarlyBuyer(address sniper);

    event SwapAndLiquify(
        uint256 tokensSwapped,
        uint256 ethReceived,
        uint256 tokensIntoLiquidity
    );

    constructor() ERC20("Berkshire Hathaway", "BRK") {
        address contractOwner = msg.sender;

        IDexRouter _dexRouter = IDexRouter(
            0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D
        );
        dexRouter = _dexRouter;

        lpPair = IDexFactory(_dexRouter.factory()).createPair(
            address(this),
            _dexRouter.WETH()
        );
        _excludeFromMaxTransaction(address(lpPair), true);
        _setAutomatedMarketMakerPair(address(lpPair), true);

        uint256 totalSupply = 1_000_000_000 * 1e18;

        maxBuyAmount = (totalSupply * 10) / 1000;
        maxSellAmount = (totalSupply * 10) / 1000;
        maxWalletAmount = (totalSupply * 10) / 1000;
        swapTokensAtAmount = (totalSupply * 1) / 1000;

        // Initial buy and sell fees to punish bots
        buyTaxFee = 30;
        buyTotalFees = buyTaxFee;

        sellTaxFee = 70;
        sellTotalFees = sellTaxFee;

        taxAddress = msg.sender;

        _excludeFromMaxTransaction(contractOwner, true);
        _excludeFromMaxTransaction(address(this), true);
        _excludeFromMaxTransaction(address(0xdead), true);
        _excludeFromMaxTransaction(taxAddress, true);

        excludeFromFees(contractOwner, true);
        excludeFromFees(address(this), true);
        excludeFromFees(address(0xdead), true);
        excludeFromFees(taxAddress, true);

        _mint(contractOwner, totalSupply);
        transferOwnership(contractOwner);
    }

    receive() external payable {}

    function enableTrading(uint256 deadBlocks) external onlyOwner {
        require(!tradingActive, "Cannot reenable trading");
        tradingActive = true;
        swapEnabled = true;
        tradingActiveBlock = block.number;
        blockForPenaltyEnd = tradingActiveBlock + deadBlocks;
        emit EnabledTrading();
    }

    function removeLimits() external onlyOwner {
        limitsInEffect = false;
        transferDelayEnabled = false;
        emit RemovedLimits();
    }

    function manageBoughtEarly(address wallet, bool flag) external onlyOwner {
        boughtEarly[wallet] = flag;
    }

    function massManageBoughtEarly(
        address[] calldata wallets,
        bool flag
    ) external onlyOwner {
        for (uint256 i = 0; i < wallets.length; i++) {
            boughtEarly[wallets[i]] = flag;
        }
    }

    function disableTransferDelay() external onlyOwner {
        transferDelayEnabled = false;
    }

    function updateMaxBuyAmount(uint256 newNum) external onlyOwner {
        require(
            newNum >= ((totalSupply() * 2) / 1000) / 1e18,
            "Cannot set max buy amount lower than 0.2%"
        );
        maxBuyAmount = newNum * (10 ** 18);
        emit UpdatedMaxBuyAmount(maxBuyAmount);
    }

    function updateMaxSellAmount(uint256 newNum) external onlyOwner {
        require(
            newNum >= ((totalSupply() * 2) / 1000) / 1e18,
            "Cannot set max sell amount lower than 0.2%"
        );
        maxSellAmount = newNum * (10 ** 18);
        emit UpdatedMaxSellAmount(maxSellAmount);
    }

    function updateMaxWalletAmount(uint256 newNum) external onlyOwner {
        require(
            newNum >= ((totalSupply() * 3) / 1000) / 1e18,
            "Cannot set max wallet amount lower than 0.3%"
        );
        maxWalletAmount = newNum * (10 ** 18);
        emit UpdatedMaxWalletAmount(maxWalletAmount);
    }

    function updateSwapTokensAtAmount(uint256 newAmount) external onlyOwner {
        require(
            newAmount >= (totalSupply() * 1) / 100000,
            "Swap amount cannot be lower than 0.001% total supply."
        );
        require(
            newAmount <= (totalSupply() * 1) / 1000,
            "Swap amount cannot be higher than 0.1% total supply."
        );
        swapTokensAtAmount = newAmount;
    }

    function _excludeFromMaxTransaction(
        address updAds,
        bool isExcluded
    ) private {
        _isExcludedMaxTransactionAmount[updAds] = isExcluded;
        emit MaxTransactionExclusion(updAds, isExcluded);
    }

    function excludeFromMaxTransaction(
        address updAds,
        bool isEx
    ) external onlyOwner {
        if (!isEx) {
            require(
                updAds != lpPair,
                "Cannot remove Uniswap pair from max txn"
            );
        }
        _isExcludedMaxTransactionAmount[updAds] = isEx;
    }

    function setAutomatedMarketMakerPair(
        address pair,
        bool value
    ) external onlyOwner {
        require(
            pair != lpPair,
            "The pair cannot be removed from automatedMarketMakerPairs"
        );

        _setAutomatedMarketMakerPair(pair, value);
        emit SetAutomatedMarketMakerPair(pair, value);
    }

    function _setAutomatedMarketMakerPair(address pair, bool value) private {
        automatedMarketMakerPairs[pair] = value;

        _excludeFromMaxTransaction(pair, value);
        emit SetAutomatedMarketMakerPair(pair, value);
    }

    function setSwapToEth(bool _swapToEth) public onlyOwner {
        swapToEth = _swapToEth;
    }

    function updateBuyFees(uint256 _taxFee) external onlyOwner {
        buyTaxFee = _taxFee;
        buyTotalFees = buyTaxFee;
        require(buyTotalFees <= 10, "Must keep fees at 10% or less.");
    }

    function updateSellFees(uint256 _taxFee) external onlyOwner {
        sellTaxFee = _taxFee;
        sellTotalFees = sellTaxFee;
        require(sellTotalFees <= 10, "Must keep fees at 10% or less.");
    }

    function excludeFromFees(address account, bool excluded) public onlyOwner {
        _isExcludedFromFees[account] = excluded;
        emit ExcludeFromFees(account, excluded);
    }

    function _transfer(
        address from,
        address to,
        uint256 amount
    ) internal override {
        require(from != address(0), "ERC20: transfer from the zero address");
        require(to != address(0), "ERC20: transfer to the zero address");
        require(amount > 0, "amount must be greater than 0");

        if (!tradingActive) {
            require(
                _isExcludedFromFees[from] || _isExcludedFromFees[to],
                "Trading is not active."
            );
        }

        if (blockForPenaltyEnd > 0) {
            require(
                !boughtEarly[from] || to == owner() || to == address(0xdead),
                "Bots cannot transfer tokens in or out except to owner or dead address."
            );
        }

        if (limitsInEffect) {
            if (
                from != owner() &&
                to != owner() &&
                to != address(0) &&
                to != address(0xdead) &&
                !_isExcludedFromFees[from] &&
                !_isExcludedFromFees[to]
            ) {
                if (transferDelayEnabled) {
                    if (to != address(dexRouter) && to != address(lpPair)) {
                        require(
                            _holderLastTransferTimestamp[tx.origin] <
                                block.number - 2 &&
                                _holderLastTransferTimestamp[to] <
                                block.number - 2,
                            "_transfer:: Transfer Delay enabled.  Try again later."
                        );
                        _holderLastTransferTimestamp[tx.origin] = block.number;
                        _holderLastTransferTimestamp[to] = block.number;
                    }
                }

                if (
                    automatedMarketMakerPairs[from] &&
                    !_isExcludedMaxTransactionAmount[to]
                ) {
                    require(
                        amount <= maxBuyAmount,
                        "Buy transfer amount exceeds the max buy."
                    );
                    require(
                        amount + balanceOf(to) <= maxWalletAmount,
                        "Cannot exceed max wallet."
                    );
                } else if (
                    automatedMarketMakerPairs[to] &&
                    !_isExcludedMaxTransactionAmount[from]
                ) {
                    require(
                        amount <= maxSellAmount,
                        "Sell transfer amount exceeds the max sell."
                    );
                } else if (!_isExcludedMaxTransactionAmount[to]) {
                    require(
                        amount + balanceOf(to) <= maxWalletAmount,
                        "Cannot exceed max wallet."
                    );
                }
            }
        }

        uint256 contractTokenBalance = balanceOf(address(this));

        bool canSwap = contractTokenBalance >= swapTokensAtAmount;

        if (
            canSwap &&
            swapEnabled &&
            !swapping &&
            !automatedMarketMakerPairs[from] &&
            !_isExcludedFromFees[from] &&
            !_isExcludedFromFees[to]
        ) {
            swapping = true;

            swapBack();

            swapping = false;
        }

        bool takeFee = true;
        if (_isExcludedFromFees[from] || _isExcludedFromFees[to]) {
            takeFee = false;
        }

        uint256 fees = 0;
        if (takeFee) {
            if (
                earlyBuyPenaltyInEffect() &&
                automatedMarketMakerPairs[from] &&
                !automatedMarketMakerPairs[to] &&
                buyTotalFees > 0
            ) {
                if (!boughtEarly[to]) {
                    boughtEarly[to] = true;
                    botsCaught += 1;
                    emit CaughtEarlyBuyer(to);
                }

                fees = (amount * 99) / 100;
                tokensForTax += (fees * buyTaxFee) / buyTotalFees;
            } else if (automatedMarketMakerPairs[to] && sellTotalFees > 0) {
                fees = (amount * sellTotalFees) / 100;
                tokensForTax += (fees * sellTaxFee) / sellTotalFees;
            } else if (automatedMarketMakerPairs[from] && buyTotalFees > 0) {
                fees = (amount * buyTotalFees) / 100;
                tokensForTax += (fees * buyTaxFee) / buyTotalFees;
            }

            if (fees > 0) {
                super._transfer(from, address(this), fees);
            }

            amount -= fees;
        }

        super._transfer(from, to, amount);
    }

    function earlyBuyPenaltyInEffect() public view returns (bool) {
        return block.number < blockForPenaltyEnd;
    }

    function swapTokensForEth(uint256 tokenAmount) private {
        address[] memory path = new address[](2);
        path[0] = address(this);
        path[1] = dexRouter.WETH();

        _approve(address(this), address(dexRouter), tokenAmount);

        dexRouter.swapExactTokensForETHSupportingFeeOnTransferTokens(
            tokenAmount,
            0,
            path,
            address(this),
            block.timestamp
        );
    }

    function swapBack() private {
        uint256 contractBalance = balanceOf(address(this));
        uint256 totalTokensToSwap = tokensForTax;

        if (contractBalance == 0 || totalTokensToSwap == 0) {
            return;
        }

        if (contractBalance > swapTokensAtAmount * 20) {
            contractBalance = swapTokensAtAmount * 20;
        }

        bool success;

        if (swapToEth) {
            swapTokensForEth(contractBalance);
            tokensForTax = 0;
            (success, ) = address(taxAddress).call{
                value: address(this).balance
            }("");
        }

        if (!swapToEth) {
            _transfer(address(this), taxAddress, contractBalance);
            tokensForTax = 0;
            success = true;
        }
    }

    // Withdraw ETH from contract address
    function withdrawStuckETH() external onlyOwner {
        bool success;
        (success, ) = address(msg.sender).call{value: address(this).balance}(
            ""
        );
    }

    function updateTaxAddress(address _taxAddress) external onlyOwner {
        require(_taxAddress != address(0), "_taxAddress address cannot be 0");
        taxAddress = payable(_taxAddress);
    }

    function forceSwapBack() external onlyOwner {
        require(
            balanceOf(address(this)) >= swapTokensAtAmount,
            "Can only swap when token amount is at or higher than restriction"
        );
        swapping = true;
        swapBack();
        swapping = false;
        emit OwnerForcedSwapBack(block.timestamp);
    }
}