using System;
using System.Collections.Generic;
using System.Runtime.CompilerServices;
using System.Threading.Tasks;

namespace Swan.Logging {
  /// <summary>
  /// Entry-point for logging. Use this static class to register/unregister
  /// loggers instances. By default, the <c>ConsoleLogger</c> is registered.
  /// </summary>
  public static class Logger {
    /*private static readonly Object SyncLock = new Object();*/
    // [Obsolete("NEED", false)]
    private static readonly List<ILogger> Loggers = new List<ILogger>();

    // [Obsolete("NEED", false)]
    private static UInt64 _loggingSequence;

    // [Obsolete("NEED", false)]
    static Logger() {
      if(Terminal.IsConsolePresent) {
        Loggers.Add(ConsoleLogger.Instance);
      }

      if(DebugLogger.IsDebuggerAttached) {
        Loggers.Add(DebugLogger.Instance);
      }
    }

    #region Extended Public API

    /// <summary>
    /// Logs an error message to the console's standard error.
    /// </summary>
    /// <param name="ex">The ex.</param>
    /// <param name="source">The source.</param>
    /// <param name="message">The message.</param>
    /// <param name="callerMemberName">Name of the caller member. This is automatically populated.</param>
    /// <param name="callerFilePath">The caller file path. This is automatically populated.</param>
    /// <param name="callerLineNumber">The caller line number. This is automatically populated.</param>
    // [Obsolete("NEED", false)]
    public static void Log(this Exception ex, String source = null, String message = null, [CallerMemberName] String callerMemberName = "", [CallerFilePath] String callerFilePath = "", [CallerLineNumber] Int32 callerLineNumber = 0) => LogMessage(LogLevel.Error, message ?? ex.Message, source ?? ex.Source, ex, callerMemberName, callerFilePath, callerLineNumber);

    #endregion

    // [Obsolete("NEED", false)]
    private static void LogMessage(LogLevel logLevel, String message, String sourceName, Object extendedData, String callerMemberName, String callerFilePath, Int32 callerLineNumber) {
      UInt64 sequence = _loggingSequence;
      DateTime date = DateTime.UtcNow;
      _loggingSequence++;

      String loggerMessage = String.IsNullOrWhiteSpace(message) ? String.Empty : message.RemoveControlCharsExcept('\n');

      LogMessageReceivedEventArgs eventArgs = new LogMessageReceivedEventArgs(sequence, logLevel, date, sourceName, loggerMessage, extendedData, callerMemberName, callerFilePath, callerLineNumber);

      foreach(ILogger logger in Loggers) {
        _ = Task.Run(() => {
          if(logger.LogLevel <= logLevel) {
            logger.Log(eventArgs);
          }
        });
      }
    }
  }
}