RoyalSwan

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.27;

interface IERC20 {
    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);

    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;
    }
}

/**
 * @dev Contract module which provides a basic access control mechanism.
 */
abstract contract Ownable is Context {
    address private _owner;

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

    constructor() {
        _transferOwnership(_msgSender());
    }

    function owner() public view virtual returns (address) {
        return _owner;
    }

    modifier onlyOwner() {
        require(owner() == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Renounces ownership of the contract permanently.
     */
    function renounceOwnership() public virtual onlyOwner {
        _transferOwnership(address(0));
    }

    function _transferOwnership(address newOwner) internal virtual {
        address oldOwner = _owner;
        _owner = newOwner;
        emit OwnershipTransferred(oldOwner, newOwner);
    }
}

/**
 * @dev Standard ERC20 implementation with gas optimizations for DEX compatibility.
 */
contract ERC20 is Context, IERC20 {
    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 returns (string memory) {
        return _name;
    }

    function symbol() public view virtual returns (string memory) {
        return _symbol;
    }

    function decimals() public pure virtual 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 zero address");
        require(to != address(0), "ERC20: transfer to zero address");

        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);
    }

    function _mint(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: mint to zero address");

        unchecked {
            _totalSupply += amount;
            _balances[account] += amount;
        }

        emit Transfer(address(0), account, amount);
    }

    function _burn(address account, uint256 amount) internal virtual {
        require(account != address(0), "ERC20: burn from zero address");

        uint256 accountBalance = _balances[account];
        require(accountBalance >= amount, "ERC20: burn exceeds balance");

        unchecked {
            _balances[account] = accountBalance - amount;
            _totalSupply -= amount;
        }

        emit Transfer(account, address(0), amount);
    }

    function _approve(address owner_, address spender, uint256 amount) internal virtual {
        require(owner_ != address(0), "ERC20: approve from zero address");
        require(spender != address(0), "ERC20: approve to 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);
            }
        }
    }
}

/**
 * @dev Extension of {ERC20} that allows token holders to destroy tokens.
 */
abstract contract ERC20Burnable is ERC20 {
    function burn(uint256 amount) public virtual {
        _burn(_msgSender(), amount);
    }

    function burnFrom(address account, uint256 amount) public virtual {
        _spendAllowance(account, _msgSender(), amount);
        _burn(account, amount);
    }
}

/**
 * @title Royal Swan Token
 * @dev Fully DEX-compatible token with immediate ownership renouncement.
 * Optimized for Uniswap, PancakeSwap, and other DEX platforms.
 */
contract RoyalSwan is ERC20, ERC20Burnable, Ownable {
    
    /**
     * @dev Sets the values for {name} and {symbol}, mints initial supply,
     * and immediately renounces ownership for full decentralization.
     */
    constructor() ERC20("Royal Swan", "ROLSN") {
        // Mint initial supply - 100 million tokens
        _mint(msg.sender, 100_000_000 * 10 ** decimals());
        
        // Immediately renounce ownership for complete decentralization
        // This makes the contract fully immutable and DEX-friendly
        renounceOwnership();
    }
}