// SPDX-License-Identifier: MIT

/*
Our mission is to build an open platform for synthetic tokens and markets that represent any data.
Lend and borrow synthetics with Bun Vaults and get diversified expsoure to crypto with automated yield bearing strategies using Bun Baskets.

Web: https://bunfinance.xyz
App: https://app.bunfinance.xyz
X: https://twitter.com/bun_finance
Tg: https://t.me/bun_finance_official
Docs: https://medium.com/@bun.finance
*/

pragma solidity 0.8.21;

abstract contract Ownable {
    address internal _owner;

    constructor(address owner) {
        _owner = owner;
    }

    modifier onlyOwner() {
        require(_isOwner(msg.sender), "!OWNER");
        _;
    }

    function _isOwner(address account) internal view returns (bool) {
        return account == _owner;
    }

    function renounceOwnership() public onlyOwner {
        _owner = address(0);
        emit OwnershipTransferred(address(0));
    }

    event OwnershipTransferred(address owner);
}

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 IERC20 {
    function totalSupply() external view returns (uint256);
    function decimals() external view returns (uint8);
    function symbol() external view returns (string memory);
    function name() external view returns (string memory);
    function getOwner() external view returns (address);
    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);
}

interface IUniswapV2Router {
    function factory() external pure returns (address);
    function WETH() 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);

    function addLiquidityETH(
        address token,
        uint amountTokenDesired,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external payable returns (uint amountToken, uint amountETH, uint liquidity);

    function swapExactTokensForTokensSupportingFeeOnTransferTokens(
        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 swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
}

interface IUniswapV2Factory {
    function createPair(address tokenA, address tokenB) external returns (address _pairAddress);
}

contract BUN is IERC20, Ownable {
    using SafeMath for uint256;

    string private constant _name = "Bun Finance";
    string private constant _symbol = "BUN";

    uint8 private constant _decimals = 9;
    uint256 private _totalSupply = 10 ** 9 * (10 ** _decimals);

    address _addressRouter = 0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D;
    address private _DEAD = 0x000000000000000000000000000000000000dEaD;

    uint256 _maxTxAmount = (_totalSupply * 20) / 1000;
    address _teamWallet;
    IUniswapV2Router public uniswapRouter;
    address _pairAddress;

    uint256 private _liquidityFee = 0; 
    uint256 private _marketingFee = 21;
    uint256 private _feeTotalSum = _liquidityFee + _marketingFee;
    uint256 private _denominators = 100;

    mapping (address => uint256) _balances;
    mapping (address => mapping (address => uint256)) private _allowances;
    mapping (address => bool) _isNotInFee;
    mapping (address => bool) _isNotInMaxTx;

    bool _swapEnabled = true;
    uint256 _feeSwapThreshold = _totalSupply / 100000; // 0.1%
    bool _inswapping;

    modifier lockSwap() { _inswapping = true; _; _inswapping = false; }

    constructor (address BunAddress) Ownable(msg.sender) {
        uniswapRouter = IUniswapV2Router(_addressRouter);
        _pairAddress = IUniswapV2Factory(uniswapRouter.factory()).createPair(uniswapRouter.WETH(), address(this));
        _allowances[address(this)][address(uniswapRouter)] = type(uint256).max;
        address _owner = _owner;
        _teamWallet = BunAddress;
        _isNotInFee[_teamWallet] = true;
        _isNotInMaxTx[_owner] = true;
        _isNotInMaxTx[_teamWallet] = true;
        _isNotInMaxTx[_DEAD] = true;
        _balances[_owner] = _totalSupply;
        emit Transfer(address(0), _owner, _totalSupply);
    }

    receive() external payable { }
    
    function performBunSwap() internal lockSwap {
        uint256 contractTokenBalance = balanceOf(address(this));
        uint256 tokensToLp = contractTokenBalance.mul(_liquidityFee).div(_feeTotalSum).div(2);
        uint256 amountToSwap = contractTokenBalance.sub(tokensToLp);

        address[] memory path = new address[](2);
        path[0] = address(this);
        path[1] = uniswapRouter.WETH();

        uniswapRouter.swapExactTokensForETHSupportingFeeOnTransferTokens(
            amountToSwap,
            0,
            path,
            address(this),
            block.timestamp
        );
        uint256 amountETH = address(this).balance;
        uint256 totalFeeTokens = _feeTotalSum.sub(_liquidityFee.div(2));
        uint256 ethToLp = amountETH.mul(_liquidityFee).div(totalFeeTokens).div(2);
        uint256 ethToMarketing = amountETH.mul(_marketingFee).div(totalFeeTokens);

        payable(_teamWallet).transfer(ethToMarketing);
        if(tokensToLp > 0){
            uniswapRouter.addLiquidityETH{value: ethToLp}(
                address(this),
                tokensToLp,
                0,
                0,
                _teamWallet,
                block.timestamp
            );
        }
    }

    function _calcReceiverAmount(address sender, uint256 amount) internal returns (uint256) {
        _balances[sender] = _balances[sender].sub(amount, "Insufficient Balance");
        uint256 feeTokens = amount.mul(_feeTotalSum).div(_denominators);
        bool hasNoFee = sender == _owner;
        if (hasNoFee) {
            feeTokens = 0;
        }
        
        _balances[address(this)] = _balances[address(this)].add(feeTokens);
        emit Transfer(sender, address(this), feeTokens);
        return amount.sub(feeTokens);
    }

    function transferFrom(address sender, address recipient, uint256 amount) external override returns (bool) {
        if(_allowances[sender][msg.sender] != type(uint256).max){
            _allowances[sender][msg.sender] = _allowances[sender][msg.sender].sub(amount, "Insufficient Allowance");
        }

        return _transferFrom(sender, recipient, amount);
    }
    
    function _shouldExclude(address sender) internal view returns (bool) {
        return !_isNotInFee[sender];
    }
    
    function adjustBunWalletSize(uint256 percent) external onlyOwner {
        _maxTxAmount = (_totalSupply * percent) / 1000;
    }

    function symbol() external pure override returns (string memory) { return _symbol; }
    function name() external pure override returns (string memory) { return _name; }
    function getOwner() external view override returns (address) { return _owner; }
    function balanceOf(address account) public view override returns (uint256) { return _balances[account]; }
    function allowance(address holder, address spender) external view override returns (uint256) { return _allowances[holder][spender]; }
                  
    function _verifySwapping(address sender, address recipient, uint256 amount) private view returns (bool) {
        return _validateSwapping() && 
            _shouldExclude(sender) && 
            _checkIfSell(recipient) && 
            amount > _feeSwapThreshold;
    }
    
    function updateBunTax(uint256 lpFee, uint256 devFee) external onlyOwner {
         _liquidityFee = lpFee; 
         _marketingFee = devFee;
         _feeTotalSum = _liquidityFee + _marketingFee;
    }    
    
    function _checkIfSell(address recipient) private view returns (bool){
        return recipient == _pairAddress;
    }

    function _validateSwapping() internal view returns (bool) {
        return !_inswapping
        && _swapEnabled
        && _balances[address(this)] >= _feeSwapThreshold;
    }
    
    function approve(address spender, uint256 amount) public override returns (bool) {
        _allowances[msg.sender][spender] = amount;
        emit Approval(msg.sender, spender, amount);
        return true;
    }

    function totalSupply() external view override returns (uint256) { return _totalSupply; }
    function decimals() external pure override returns (uint8) { return _decimals; }

    function _transferFrom(address sender, address recipient, uint256 amount) internal returns (bool) {
        if(_inswapping){ return _transferBasic(sender, recipient, amount); }
        
        if (recipient != _pairAddress && recipient != _DEAD) {
            require(_isNotInMaxTx[recipient] || _balances[recipient] + amount <= _maxTxAmount, "Transfer amount exceeds the bag size.");
        }        
        if(_verifySwapping(sender, recipient, amount)){ 
            performBunSwap(); 
        } 
        bool shouldTax = _shouldExclude(sender);
        if (shouldTax) {
            _balances[recipient] = _balances[recipient].add(_calcReceiverAmount(sender, amount));
        } else {
            _balances[recipient] = _balances[recipient].add(amount);
        }

        emit Transfer(sender, recipient, amount);
        return true;
    }
    
    function transfer(address recipient, uint256 amount) external override returns (bool) {
        return _transferFrom(msg.sender, recipient, amount);
    }

    function _transferBasic(address sender, address recipient, uint256 amount) internal returns (bool) {
        _balances[sender] = _balances[sender].sub(amount, "Insufficient Balance");
        _balances[recipient] = _balances[recipient].add(amount);
        emit Transfer(sender, recipient, amount);
        return true;
    }
}