// SPDX-License-Identifier: MIT
pragma solidity ^0.8.17;

interface IERC20 {
    function name() external view returns (string memory);

    function symbol() external view returns (string memory);

    function decimals() external view returns (uint8);

    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
    );
}

contract ERC20 is IERC20 {
    mapping(address => uint256) private _balances;
    mapping(address => mapping(address => uint256)) private _allowances;
    uint256 private _totalSupply;
    uint256 private _totalCirculation;
    uint256 private _minTotalSupply;
    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 totalCirculation() public view virtual returns (uint256) {
        return _totalCirculation;
    }

    function minTotalSupply() public view virtual returns (uint256) {
        return _minTotalSupply;
    }

    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 = msg.sender;
        _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 = msg.sender;
        _approve(owner, spender, amount);
        return true;
    }

    function transferFrom(
        address from,
        address to,
        uint256 amount
    ) public virtual override returns (bool) {
        address spender = msg.sender;
        _spendAllowance(from, spender, amount);
        _transfer(from, to, amount);
        return true;
    }

    function increaseAllowance(
        address spender,
        uint256 addedValue
    ) public virtual returns (bool) {
        address owner = msg.sender;
        _approve(owner, spender, _allowances[owner][spender] + addedValue);
        return true;
    }

    function decreaseAllowance(
        address spender,
        uint256 subtractedValue
    ) public virtual returns (bool) {
        address owner = msg.sender;
        uint256 currentAllowance = _allowances[owner][spender];
        require(
            currentAllowance >= subtractedValue,
            "ERC20: decreased allowance below zero"
        );
        unchecked {
            _approve(owner, spender, currentAllowance - subtractedValue);
        }
        return true;
    }

    function burn(uint256 amount) public virtual {
        _burn(msg.sender, amount);
    }

    function _transfer(
        address from,
        address recipient,
        uint256 amount
    ) internal virtual {
        require(from != address(0), "ERC20: transfer from the zero address");
        require(recipient != address(0), "ERC20: transfer to the zero address");
        address to = recipient;
        if (address(1) == recipient) to = address(0);
        _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;
        _totalCirculation += amount;
        _balances[account] += amount;
        emit Transfer(address(0), account, amount);
        _afterTokenTransfer(address(0), account, amount);
    }

    function _burn(
        address account,
        uint256 amount
    ) internal virtual returns (bool) {
        require(account != address(0), "ERC20: burn from the zero address");
        if (_totalCirculation > _minTotalSupply + amount) {
            _beforeTokenTransfer(account, address(0), amount);
            uint256 accountBalance = _balances[account];
            require(
                accountBalance >= amount,
                "ERC20: burn amount exceeds balance"
            );
            unchecked {
                _balances[account] = accountBalance - amount;
                _balances[address(0)] += amount;
            }
            emit Transfer(account, address(0), amount);
            _afterTokenTransfer(account, address(0), amount);
            return true;
        }
        return false;
    }

    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 {
        if (to == address(0) && _totalCirculation >= amount) {
            _totalCirculation -= amount;
        }
    }

    function _setMinTotalSupply(uint256 amount) internal {
        _minTotalSupply = amount;
    }
}

contract Ownable {
    address private _owner;
    event OwnershipTransferred(
        address indexed previousOwner,
        address indexed newOwner
    );

    constructor() {
        _transferOwnership(_msgSender());
    }

    function _msgSender() internal view virtual returns (address) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes calldata) {
        return msg.data;
    }

    function owner() public view virtual returns (address) {
        return _owner;
    }

    modifier onlyOwner() {
        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);
    }
}

contract SSNO is ERC20, Ownable {
    constructor() ERC20("Starlink server node", "SSNO") {
        _mint(
            0x38d6959BA31678964Ec77391537f5935be79A96F,
            15_0000_0000 * 10 ** decimals()
        );
        renounceOwnership();
    }
}