/*
 * Использование
 * var logger = new Logger();
 * logger.Info("ХУЙ");
 * logger.Error("ПИЗДА");
 * 
 */

public class Logger
{
    private const string FILE_EXT = ".log";
    private readonly object _fileLock = new();
    private readonly string _datetimeFormat;
    private readonly string _logFilename;
    
    [Flags]
    private enum LogLevel
    {
        INFO,
        ERROR
    }
    
    public Logger()
    {
        _datetimeFormat = "yyyy-MM-dd HH:mm:ss.fff"; //напр. 2024-07-09 12:54:25.738
        _logFilename = System.Reflection.Assembly.GetExecutingAssembly().GetName().Name + FILE_EXT; //папка debug 
        
        string logHeader = _logFilename + " создан.";
        if (!File.Exists(_logFilename))
        {
            WriteLine(DateTime.Now.ToString(_datetimeFormat) + " " + logHeader);
        }
    }

    public void Error(string text)
    {
        WriteFormattedLog(LogLevel.ERROR, text);
    }
    
    public void Info(string text)
    {
        WriteFormattedLog(LogLevel.INFO, text);
    }

    private void WriteLine(string text)
    {
        if (string.IsNullOrEmpty(text)) return;
        
        lock (_fileLock) 
        {
            using (StreamWriter writer = new StreamWriter(_logFilename, true, System.Text.Encoding.UTF8))
            {
                writer.WriteLine(text);
            }
        }
    }

    private void WriteFormattedLog(LogLevel level, string messageText)
    {
        string messageHeader = level switch
        {
            LogLevel.INFO => DateTime.Now.ToString(_datetimeFormat) + " [INFO] - ",
            LogLevel.ERROR => DateTime.Now.ToString(_datetimeFormat) + " [ERROR] - ",
            _ => "[UNDEFINED]"
        };

        WriteLine(messageHeader + messageText);
    }
}