// File: airenetwork.sol



// SPDX-License-Identifier: MIT                                                                               
// www.twitter.com/aire_token/
// https://t.me/airenetwork

import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/utils/Context.sol";
import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";                                        

pragma solidity 0.8.15;

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 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 AIRE is ERC20, Ownable {
    uint256 public maxBuyAmount;
    uint256 public maxSellAmount;
    uint256 public maxWallet;

    IDexRouter public dexRouter;
    address public lpPair;

    bool private swapping;
    uint256 public swapTokensAtAmount;

    address public devAddress;

    bool public limitsInEffect = true;
    bool public tradingActive = false;
    bool public swapEnabled = false;
    
     // Anti-bot and anti-whale mappings and variables
    mapping(address => uint256) private _holderLastTransferTimestamp; // to hold last Transfers temporarily during launch
    bool public transferDelayEnabled = true;

    uint256 public buyTotalFees;
    uint256 public buyDevFee;
    uint256 public buyLiquidityFee;
    uint256 public buyBurnFee;

    uint256 public sellTotalFees;
    uint256 public sellDevFee;
    uint256 public sellLiquidityFee;
    uint256 public sellBurnFee;

    uint256 public constant FEE_DIVISOR = 1000;

    uint256 public tokensForDev;
    uint256 public tokensForLiquidity;

    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 UpdatedDevAddress(address indexed newWallet);

    event MaxTransactionExclusion(address _address, bool excluded);

    event OwnerForcedSwapBack(uint256 timestamp);

    event SwapAndLiquify(
        uint256 tokensSwapped,
        uint256 ethReceived,
        uint256 tokensIntoLiquidity
    );

    constructor(string memory name_, string memory symbol_, uint256 totalSupply_) ERC20(name_, symbol_) payable {
        
        address newOwner = msg.sender; // can leave alone if owner is deployer.
        address _dexRouter;

        if(block.chainid == 1 || block.chainid == 5){
            _dexRouter = 0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D; // ETH: Uniswap V2
        } else if(block.chainid == 42161){
            _dexRouter = 0x1b02dA8Cb0d097eB8D57A175b88c7D8b47997506; // Arbitrum: SushiSwap
        } else {
            revert("Chain not configured");
        }

        // initialize router
        dexRouter = IDexRouter(_dexRouter);

        uint256 totalSupply = totalSupply_ * (10 ** decimals());
        
        maxBuyAmount = totalSupply * 4 / 1000;
        maxSellAmount = totalSupply * 12 / 1000;
        maxWallet = totalSupply * 12 / 1000;
        swapTokensAtAmount = totalSupply * 25 / 100000;

        buyDevFee = 50;
        buyLiquidityFee = 0;
        buyBurnFee = 0;
        buyTotalFees = buyDevFee + buyLiquidityFee + buyBurnFee;

        sellDevFee = 90;
        sellLiquidityFee = 0;
        sellBurnFee = 0;
        sellTotalFees = sellDevFee + sellLiquidityFee + sellBurnFee;

        devAddress = address(msg.sender);

        _excludeFromMaxTransaction(newOwner, true);
        _excludeFromMaxTransaction(address(this), true);
        _excludeFromMaxTransaction(address(0xdead), true);
        _excludeFromMaxTransaction(address(devAddress), true);
        _excludeFromMaxTransaction(address(dexRouter), true);

        excludeFromFees(newOwner, true);
        excludeFromFees(address(this), true);
        excludeFromFees(address(0xdead), true);
        excludeFromFees(address(devAddress), true);
        excludeFromFees(address(dexRouter), true);

        _mint(msg.sender, totalSupply);
        transferOwnership(newOwner);
    }

    receive() external payable {}
    
    function enableTrading() external onlyOwner {
        require(!tradingActive, "Cannot reenable trading");
        tradingActive = true;
        swapEnabled = true;
        emit EnabledTrading();
    }
    
    // remove limits after token is stable
    function removeLimits() external onlyOwner {
        limitsInEffect = false;
        transferDelayEnabled = false;
        maxBuyAmount = totalSupply();
        maxSellAmount = totalSupply();
        emit RemovedLimits();
    }

    function emergencyUpdateRouter(address router) external onlyOwner {
        require(!tradingActive, "Cannot update after trading is functional");
        dexRouter = IDexRouter(router);
    }
    
    // disable Transfer delay - cannot be reenabled
    function disableTransferDelay() external onlyOwner {
        transferDelayEnabled = false;
    }
    
    function updateMaxBuyAmount(uint256 newNum) external onlyOwner {
        require(newNum >= 1, "Cannot set max buy amount lower than 0.1%");
        maxBuyAmount = totalSupply() * newNum / 1000;
        emit UpdatedMaxBuyAmount(maxBuyAmount);
    }
    
    function updateMaxSellAmount(uint256 newNum) external onlyOwner {
        require(newNum >= 1, "Cannot set max sell amount lower than 0.1%");
        maxSellAmount = totalSupply() * newNum / 1000;
        emit UpdatedMaxSellAmount(maxSellAmount);
    }

    function updateMaxWallet(uint256 newNum) external onlyOwner {
        require(newNum >= 1, "Cannot set max wallet amount lower than %");
        maxWallet = totalSupply() * newNum / 1000;
        emit UpdatedMaxWalletAmount(maxWallet);
    }

    // change the minimum amount of tokens to sell from fees
    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 updateBuyFees(uint256 _devFee, uint256 _liquidityFee, uint256 _burnFee) external onlyOwner {
        buyDevFee = _devFee;
        buyLiquidityFee = _liquidityFee;
        buyBurnFee = _burnFee;
        buyTotalFees = buyDevFee + buyLiquidityFee + buyBurnFee;
        require(buyTotalFees <= 10 * FEE_DIVISOR / 100, "Must keep fees at 10% or less");
    }

    function updateSellFees(uint256 _devFee, uint256 _liquidityFee,uint256 _burnFee) external onlyOwner {
        sellDevFee = _devFee;
        sellLiquidityFee = _liquidityFee;
        sellBurnFee = _burnFee;
        sellTotalFees = sellDevFee + sellLiquidityFee + sellBurnFee;
        require(sellTotalFees <= 20 * FEE_DIVISOR / 100, "Must keep fees at 20% or less");
    }

    function massExcludeFromFees(address[] calldata accounts, bool excluded) external onlyOwner {
        for(uint256 i = 0; i < accounts.length; i++){
            _isExcludedFromFees[accounts[i]] = excluded;
            emit ExcludeFromFees(accounts[i], excluded);
        }
    }

    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(limitsInEffect){
            if (from != owner() && to != owner() && to != address(0) && to != address(0xdead) && !_isExcludedFromFees[from] && !_isExcludedFromFees[to]){
                
                // at launch if the transfer delay is enabled, ensure the block timestamps for purchasers is set -- during launch.  
                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;
                    }
                }
                 
                //when buy
                if (automatedMarketMakerPairs[from] && !_isExcludedMaxTransactionAmount[to]) {
                    require(amount <= maxBuyAmount, "Buy transfer amount exceeds the max buy.");
                    require(amount + balanceOf(to) <= maxWallet, "Cannot exceed max wallet");
                } 
                //when sell
                else if (automatedMarketMakerPairs[to] && !_isExcludedMaxTransactionAmount[from]) {
                    require(amount <= maxSellAmount, "Sell transfer amount exceeds the max sell.");
                }
                else if (!_isExcludedMaxTransactionAmount[to]) {
                    require(amount + balanceOf(to) <= maxWallet, "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 any account belongs to _isExcludedFromFee account then remove the fee
        if(_isExcludedFromFees[from] || _isExcludedFromFees[to]) {
            takeFee = false;
        }
        
        uint256 fees = 0;
        uint256 tokensToBurn = 0;

        // only take fees on buys/sells, do not take on wallet transfers
        if(takeFee){
            // on sell
            if (automatedMarketMakerPairs[to] && sellTotalFees > 0){
                fees = amount * sellTotalFees / FEE_DIVISOR;
                tokensForLiquidity += fees * sellLiquidityFee / sellTotalFees;
                tokensForDev += fees * sellDevFee / sellTotalFees;
                tokensToBurn = fees * sellBurnFee / buyTotalFees;
            }

            // on buy
            else if(automatedMarketMakerPairs[from] && buyTotalFees > 0) {
        	    fees = amount * buyTotalFees / FEE_DIVISOR;
        	    tokensForLiquidity += fees * buyLiquidityFee / buyTotalFees;
                tokensForDev += fees * buyDevFee / buyTotalFees;
                tokensToBurn = fees * buyBurnFee / buyTotalFees;
            }
            
            if(fees > 0){    
                super._transfer(from, address(this), fees);
                if(tokensToBurn > 0){
                    super._transfer(address(this), address(0xdead), tokensToBurn);
                }
            }
        	
        	amount -= fees;
        }

        super._transfer(from, to, amount);
    }

    function swapTokensForEth(uint256 tokenAmount) private {
        // generate the uniswap pair path of token -> weth
        address[] memory path = new address[](2);
        path[0] = address(this);
        path[1] = dexRouter.WETH();

        _approve(address(this), address(dexRouter), tokenAmount);

        // make the swap
        dexRouter.swapExactTokensForETHSupportingFeeOnTransferTokens(
            tokenAmount,
            0, // accept any amount of ETH
            path,
            address(this),
            block.timestamp
        );
    }
    
    function addLiquidity(uint256 tokenAmount, uint256 ethAmount) private {
        // approve token transfer to cover all possible scenarios
        _approve(address(this), address(dexRouter), tokenAmount);

        // add the liquidity
        dexRouter.addLiquidityETH{value: ethAmount}(
            address(this),
            tokenAmount,
            0, // slippage is unavoidable
            0, // slippage is unavoidable
            address(this),
            block.timestamp
        );
    }

    function swapBack() private {
        uint256 contractBalance = balanceOf(address(this));
        uint256 totalTokensToSwap = tokensForLiquidity + tokensForDev;
        
        if(contractBalance == 0 || totalTokensToSwap == 0) {return;}

        if(contractBalance > swapTokensAtAmount * 10){
            contractBalance = swapTokensAtAmount * 10;
        }

        bool success;
        
        // Halve the amount of liquidity tokens
        uint256 liquidityTokens = contractBalance * tokensForLiquidity / totalTokensToSwap / 2;
        
        swapTokensForEth(contractBalance - liquidityTokens); 
        
        uint256 ethBalance = address(this).balance;
        uint256 ethForLiquidity = ethBalance;

        uint256 ethForDev = ethBalance * tokensForDev / (totalTokensToSwap - (tokensForLiquidity/2));

        ethForLiquidity -= ethForDev;
            
        tokensForLiquidity = 0;
        tokensForDev = 0;
        
        if(liquidityTokens > 0 && ethForLiquidity > 0){
            addLiquidity(liquidityTokens, ethForLiquidity);
        }

        (success,) = address(devAddress).call{value: address(this).balance}("");
    }

    function transferForeignToken(address _token, address _to) external onlyOwner returns (bool _sent) {
        require(_token != address(0), "_token address cannot be 0");
        require(_token != address(this) || !tradingActive, "Can't withdraw native tokens while trading is active");
        uint256 _contractBalance = IERC20(_token).balanceOf(address(this));
        _sent = IERC20(_token).transfer(_to, _contractBalance);
    }

    // withdraw ETH if stuck or someone sends to the address
    function withdrawStuckETH() external onlyOwner {
        bool success;
        (success,) = address(msg.sender).call{value: address(this).balance}("");
    }

    function setDevAddress(address _devAddress) external onlyOwner {
        require(_devAddress != address(0), "_devAddress address cannot be 0");
        devAddress = payable(_devAddress);
    }

    // force Swap back if slippage issues.
    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);
    }

    function launch() external onlyOwner {
        require(!tradingActive, "Trading is already active, cannot relaunch.");

        //standard enable trading
        tradingActive = true;
        swapEnabled = true;
        emit EnabledTrading();

        // create pair
        lpPair = IDexFactory(dexRouter.factory()).createPair(address(this), dexRouter.WETH());
        _excludeFromMaxTransaction(address(lpPair), true);
        _setAutomatedMarketMakerPair(address(lpPair), true);
   
        // add the liquidity

        require(address(this).balance > 0, "Must have ETH on contract to launch");
        require(balanceOf(address(this)) > 0, "Must have Tokens on contract to launch");

        _approve(address(this), address(dexRouter), balanceOf(address(this)));
        dexRouter.addLiquidityETH{value: address(this).balance}(
            address(this),
            balanceOf(address(this)),
            0, // slippage is unavoidable
            0, // slippage is unavoidable
            address(msg.sender),
            block.timestamp
        );
    }
}
// File: @openzeppelin/contracts/token/ERC20/IERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.6.0) (token/ERC20/IERC20.sol)

pragma solidity ^0.8.0;

/**
 * @dev Interface of the ERC20 standard as defined in the EIP.
 */
interface IERC20 {
    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);

    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `to`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address to, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `from` to `to` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) external returns (bool);
}

// File: @openzeppelin/contracts/token/ERC20/ERC20.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (token/ERC20/ERC20.sol)

pragma solidity ^0.8.0;

import "./IERC20.sol";
import "./extensions/IERC20Metadata.sol";
import "../../utils/Context.sol";

/**
 * @dev Implementation of the {IERC20} interface.
 *
 * This implementation is agnostic to the way tokens are created. This means
 * that a supply mechanism has to be added in a derived contract using {_mint}.
 * For a generic mechanism see {ERC20PresetMinterPauser}.
 *
 * TIP: For a detailed writeup see our guide
 * https://forum.zeppelin.solutions/t/how-to-implement-erc20-supply-mechanisms/226[How
 * to implement supply mechanisms].
 *
 * We have followed general OpenZeppelin Contracts guidelines: functions revert
 * instead returning `false` on failure. This behavior is nonetheless
 * conventional and does not conflict with the expectations of ERC20
 * applications.
 *
 * Additionally, an {Approval} event is emitted on calls to {transferFrom}.
 * This allows applications to reconstruct the allowance for all accounts just
 * by listening to said events. Other implementations of the EIP may not emit
 * these events, as it isn't required by the specification.
 *
 * Finally, the non-standard {decreaseAllowance} and {increaseAllowance}
 * functions have been added to mitigate the well-known issues around setting
 * allowances. See {IERC20-approve}.
 */
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;

    /**
     * @dev Sets the values for {name} and {symbol}.
     *
     * The default value of {decimals} is 18. To select a different value for
     * {decimals} you should overload it.
     *
     * All two of these values are immutable: they can only be set once during
     * construction.
     */
    constructor(string memory name_, string memory symbol_) {
        _name = name_;
        _symbol = symbol_;
    }

    /**
     * @dev Returns the name of the token.
     */
    function name() public view virtual override returns (string memory) {
        return _name;
    }

    /**
     * @dev Returns the symbol of the token, usually a shorter version of the
     * name.
     */
    function symbol() public view virtual override returns (string memory) {
        return _symbol;
    }

    /**
     * @dev Returns the number of decimals used to get its user representation.
     * For example, if `decimals` equals `2`, a balance of `505` tokens should
     * be displayed to a user as `5.05` (`505 / 10 ** 2`).
     *
     * Tokens usually opt for a value of 18, imitating the relationship between
     * Ether and Wei. This is the value {ERC20} uses, unless this function is
     * overridden;
     *
     * NOTE: This information is only used for _display_ purposes: it in
     * no way affects any of the arithmetic of the contract, including
     * {IERC20-balanceOf} and {IERC20-transfer}.
     */
    function decimals() public view virtual override returns (uint8) {
        return 18;
    }

    /**
     * @dev See {IERC20-totalSupply}.
     */
    function totalSupply() public view virtual override returns (uint256) {
        return _totalSupply;
    }

    /**
     * @dev See {IERC20-balanceOf}.
     */
    function balanceOf(address account) public view virtual override returns (uint256) {
        return _balances[account];
    }

    /**
     * @dev See {IERC20-transfer}.
     *
     * Requirements:
     *
     * - `to` cannot be the zero address.
     * - the caller must have a balance of at least `amount`.
     */
    function transfer(address to, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _transfer(owner, to, amount);
        return true;
    }

    /**
     * @dev See {IERC20-allowance}.
     */
    function allowance(address owner, address spender) public view virtual override returns (uint256) {
        return _allowances[owner][spender];
    }

    /**
     * @dev See {IERC20-approve}.
     *
     * NOTE: If `amount` is the maximum `uint256`, the allowance is not updated on
     * `transferFrom`. This is semantically equivalent to an infinite approval.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function approve(address spender, uint256 amount) public virtual override returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, amount);
        return true;
    }

    /**
     * @dev See {IERC20-transferFrom}.
     *
     * Emits an {Approval} event indicating the updated allowance. This is not
     * required by the EIP. See the note at the beginning of {ERC20}.
     *
     * NOTE: Does not update the allowance if the current allowance
     * is the maximum `uint256`.
     *
     * Requirements:
     *
     * - `from` and `to` cannot be the zero address.
     * - `from` must have a balance of at least `amount`.
     * - the caller must have allowance for ``from``'s tokens of at least
     * `amount`.
     */
    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;
    }

    /**
     * @dev Atomically increases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     */
    function increaseAllowance(address spender, uint256 addedValue) public virtual returns (bool) {
        address owner = _msgSender();
        _approve(owner, spender, allowance(owner, spender) + addedValue);
        return true;
    }

    /**
     * @dev Atomically decreases the allowance granted to `spender` by the caller.
     *
     * This is an alternative to {approve} that can be used as a mitigation for
     * problems described in {IERC20-approve}.
     *
     * Emits an {Approval} event indicating the updated allowance.
     *
     * Requirements:
     *
     * - `spender` cannot be the zero address.
     * - `spender` must have allowance for the caller of at least
     * `subtractedValue`.
     */
    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;
    }

    /**
     * @dev Moves `amount` of tokens from `from` to `to`.
     *
     * This internal function is equivalent to {transfer}, and can be used to
     * e.g. implement automatic token fees, slashing mechanisms, etc.
     *
     * Emits a {Transfer} event.
     *
     * Requirements:
     *
     * - `from` cannot be the zero address.
     * - `to` cannot be the zero address.
     * - `from` must have a balance of at least `amount`.
     */
    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);
    }

    /** @dev Creates `amount` tokens and assigns them to `account`, increasing
     * the total supply.
     *
     * Emits a {Transfer} event with `from` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     */
    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;
        _balances[account] += amount;
        emit Transfer(address(0), account, amount);

        _afterTokenTransfer(address(0), account, amount);
    }

    /**
     * @dev Destroys `amount` tokens from `account`, reducing the
     * total supply.
     *
     * Emits a {Transfer} event with `to` set to the zero address.
     *
     * Requirements:
     *
     * - `account` cannot be the zero address.
     * - `account` must have at least `amount` tokens.
     */
    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);
    }

    /**
     * @dev Sets `amount` as the allowance of `spender` over the `owner` s tokens.
     *
     * This internal function is equivalent to `approve`, and can be used to
     * e.g. set automatic allowances for certain subsystems, etc.
     *
     * Emits an {Approval} event.
     *
     * Requirements:
     *
     * - `owner` cannot be the zero address.
     * - `spender` cannot be the zero address.
     */
    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);
    }

    /**
     * @dev Updates `owner` s allowance for `spender` based on spent `amount`.
     *
     * Does not update the allowance amount in case of infinite allowance.
     * Revert if not enough allowance is available.
     *
     * Might emit an {Approval} event.
     */
    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);
            }
        }
    }

    /**
     * @dev Hook that is called before any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * will be transferred to `to`.
     * - when `from` is zero, `amount` tokens will be minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens will be burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _beforeTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}

    /**
     * @dev Hook that is called after any transfer of tokens. This includes
     * minting and burning.
     *
     * Calling conditions:
     *
     * - when `from` and `to` are both non-zero, `amount` of ``from``'s tokens
     * has been transferred to `to`.
     * - when `from` is zero, `amount` tokens have been minted for `to`.
     * - when `to` is zero, `amount` of ``from``'s tokens have been burned.
     * - `from` and `to` are never both zero.
     *
     * To learn more about hooks, head to xref:ROOT:extending-contracts.adoc#using-hooks[Using Hooks].
     */
    function _afterTokenTransfer(
        address from,
        address to,
        uint256 amount
    ) internal virtual {}
}

// File: @openzeppelin/contracts/utils/Context.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (utils/Context.sol)

pragma solidity ^0.8.0;

/**
 * @dev Provides information about the current execution context, including the
 * sender of the transaction and its data. While these are generally available
 * via msg.sender and msg.data, they should not be accessed in such a direct
 * manner, since when dealing with meta-transactions the account sending and
 * paying for execution may not be the actual sender (as far as an application
 * is concerned).
 *
 * This contract is only required for intermediate, library-like contracts.
 */
abstract contract Context {
    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }
}

// File: @openzeppelin/contracts/access/Ownable.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.7.0) (access/Ownable.sol)

pragma solidity ^0.8.0;

import "../utils/Context.sol";

/**
 * @dev Contract module which provides a basic access control mechanism, where
 * there is an account (an owner) that can be granted exclusive access to
 * specific functions.
 *
 * By default, the owner account will be the one that deploys the contract. This
 * can later be changed with {transferOwnership}.
 *
 * This module is used through inheritance. It will make available the modifier
 * `onlyOwner`, which can be applied to your functions to restrict their use to
 * the owner.
 */
abstract contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor() {
        _transferOwnership(_msgSender());
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        _checkOwner();
        _;
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view virtual returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if the sender is not the owner.
     */
    function _checkOwner() internal view virtual {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        _transferOwnership(newOwner);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Internal function without access restriction.
     */
    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

// File: @openzeppelin/contracts/token/ERC20/extensions/IERC20Metadata.sol



// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC20/extensions/IERC20Metadata.sol)

pragma solidity ^0.8.0;

import "../IERC20.sol";

/**
 * @dev Interface for the optional metadata functions from the ERC20 standard.
 *
 * _Available since v4.1._
 */
interface IERC20Metadata is IERC20 {
    /**
     * @dev Returns the name of the token.
     */
    function name() external view returns (string memory);

    /**
     * @dev Returns the symbol of the token.
     */
    function symbol() external view returns (string memory);

    /**
     * @dev Returns the decimals places of the token.
     */
    function decimals() external view returns (uint8);
}