using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Diagnostics;
using System.IO;
using System.Runtime.InteropServices;

using log4net;
using log4net.Config;
using log4net.Layout;
using log4net.Appender;
using log4net.Core;
using log4net.ObjectRenderer;
using log4net.Util;

using Perforce.P4;


namespace P4Connect
{
    public static class Logger
    {
        static Log4netTraceListener p4Listener = null;

        public static void Initialize()
        {
            if (!Config.EnableLog)
            {
                Disable();
                return;
            }

            try
            {
                UnityEngine.Debug.Log("Initialize Logger");

                ConfigureAllLogging();

                p4Listener = new Log4netTraceListener();

                // Write the initial trace message to the console trace listener.
                p4Listener.WriteLine(DateTime.Now.ToString() + " - Logger Initialized.");

                // Add the new console trace listener to the collection of trace listeners.
                Trace.Listeners.Add(p4Listener);

                // Hook the Bridge logging calls up using the .NetLog delegate
                Perforce.P4.LogFile.SetLoggingFunction(NetLog);

                Perforce.P4.P4Exception.MinThrowLevel = Perforce.P4.ErrorSeverity.E_INFO;       // how much noise p4api.net makes
                
                Trace.Flush();
            }
            catch (Exception e)
            {
                UnityEngine.Debug.Log("Exception in Logger.Initialize: " + e.Message);
                UnityEngine.Debug.Log("   src: " + e.Source);
                UnityEngine.Debug.Log("   stack: " + e.StackTrace);

                Disable();
            }
        }

        public static void Enable()
        {
            Initialize();
        }

        public static void Disable()
        {
            if (p4Listener != null)
            {
                p4Listener.Dispose();
                p4Listener = null;
            }
        }

        /// <summary>
        ///  Configure logging to write to default log and the Unity console output.
        /// </summary>
        public static void ConfigureAllLogging()
        {
            var patternLayout = new PatternLayout
                              {
                                  ConversionPattern = "%date %-5level %logger.%method - %message%newline"
                              };
            patternLayout.ActivateOptions();

            // setup the appender that writes to the logfile
            var fileAppender = new log4net.Appender.RollingFileAppender
                               {
                                   AppendToFile = true,
                                   File = Config.LogPath,
                                   Layout = patternLayout,
                                   MaxSizeRollBackups = 5,
                                   MaximumFileSize = "1GB",
                                   RollingStyle = RollingFileAppender.RollingMode.Size,
                                   StaticLogFileName = true
                               };
            fileAppender.ActivateOptions();

            var unityLogger = new UnityAppender
                              {
                                  Layout = patternLayout
                              };
            unityLogger.ActivateOptions();

            // See if logging.xml is available as an asset
            string ConfigPath = Main.DataPath + "\\P4Connect\\Editor\\logging.xml";

            UnityEngine.Debug.Log("Looking for logging config at " + ConfigPath);
            if (System.IO.File.Exists(ConfigPath))
            {
                UnityEngine.Debug.Log("Reading log4net configuration asset");
                using (System.IO.Stream fs = System.IO.File.OpenRead(ConfigPath))
                {
                    log4net.Config.XmlConfigurator.Configure(fs);     // Customized configuration from asset
                }
            }
            else
            {
                UnityEngine.Debug.Log("Using log4net defaults");
                BasicConfigurator.Configure(unityLogger, fileAppender);   // "Wired-in" default configuration

                ILog log = LogManager.GetLogger(typeof(Logger));
                var repo = LogManager.GetRepository();
            }
        }

        /// <summary> An appender which logs to the unity console. </summary>
        private class UnityAppender : AppenderSkeleton
        {   
            /// <inheritdoc />
            protected override void Append(log4net.Core.LoggingEvent loggingEvent)
            {
                string message = RenderLoggingEvent(loggingEvent);
                LogLevel l = GetLogLevelFromLog4NetLevel(loggingEvent.Level);

                if (l <= Config.ConsoleLogLevel)  // Filter Log output to console
                {
                    // Write to the console
                    if (Level.Compare(loggingEvent.Level, Level.Error) >= 0)
                    {
                        // everything above or equal to error is an error
                        UnityEngine.Debug.LogError(message);
                    }
                    else if (Level.Compare(loggingEvent.Level, Level.Warn) >= 0)
                    {
                        // everything that is a warning up to error is logged as warning
                        UnityEngine.Debug.LogWarning(message);
                    }
                    else
                    {
                        // everything else we'll just log normally
                        UnityEngine.Debug.Log(message);
                    }
                }
            }
        }

 

        public class Log4netTraceListener : System.Diagnostics.TraceListener
        {
            private readonly log4net.ILog _log;
            public Log4netTraceListener()
            {

                _log = log4net.LogManager.GetLogger("trace");
            }

            public Log4netTraceListener(log4net.ILog log)
            {
                _log = log;
            }

            public override void Write(string message)
            {
                if (_log != null)
                {
                    _log.Debug(message);
                }
            }

            public override void WriteLine(string message)
            {
                if (_log != null)
                {
                    _log.Debug(message);
                }
            }
        }

        ///    Log_Level. From P4API The lower the level, the more severe the issue
        ///     0   fatal
        ///     1   error
        ///     2   warning
        ///     3   information
        ///     4+  debugging messages
        ///     
        public enum LogLevel
        {
            Fatal,
            Error,
            Warn,
            Info,
            Debug
        };

        // Translate a Log4Net Level enum into a Logger.LogLevel enum
        public static LogLevel GetLogLevelFromLog4NetLevel(Level l)
        {
            if (l >= Level.Debug)
                return LogLevel.Debug;
            if (l >= Level.Info)
                return LogLevel.Info;
            if (l >= Level.Warn)
                return LogLevel.Warn;
            if (l >= Level.Error)
                return LogLevel.Error;
            return LogLevel.Fatal;
        }

        public static void NetLog(int log_level, String source, String message)
        {
            log4net.ILog _log = log4net.LogManager.GetLogger(source);

            LogLevel level = (LogLevel)log_level;
            switch (level)
            {
                case LogLevel.Fatal:
                    _log.Fatal(message);
                    break;
                case LogLevel.Error:
                    _log.Error(message);
                    break;
                case LogLevel.Warn:
                    _log.Warn(message);
                    break;
                case LogLevel.Info:
                    _log.Info(message);
                    break;
                case LogLevel.Debug:
                    _log.Debug(message);
                    break;
            }
        }

        private static string ARRAY_DELIMITER = ", ";
        private static string ARRAY_BRACES = "[{0}]";
        private static string LEFT_BRACE = "[";
        private static string RIGHT_BRACE = "]";
        private static string NULL_STRING = "null";

        public static string ToStringNullSafe(this object value)
        {
            return(value ?? "null").ToString();
        }

        public static string StringArrayToString(string[] a)
        {
            if (a == null)
                return NULL_STRING;

            return string.Format(ARRAY_BRACES, string.Join(ARRAY_DELIMITER, a));
        }

        public static string FilesAndOpListToString(List<Engine.FilesAndOp> a)
        {
            if (a == null)
                return NULL_STRING;

            StringBuilder sb = new StringBuilder();
            sb.Append(LEFT_BRACE);
            bool first = true;

            foreach(Engine.FilesAndOp fao in a)
            {
                if (!first)
                    sb.Append(ARRAY_DELIMITER);

                sb.AppendFormat("op: {0} file: {1} meta: {2} move: {3}",
                    fao.FileOp, fao.File, fao.Meta, fao.MoveToFile);
                
                first = false; 
            }
            sb.Append(RIGHT_BRACE);
            return sb.ToString();
        }

        public static string FileSpecListToString(IList<FileSpec> a)
        {
            if (a == null)
                return NULL_STRING;

            StringBuilder sb = new StringBuilder();
            sb.Append(LEFT_BRACE);
            bool first = true;

            foreach (Perforce.P4.FileSpec spec in a)
            {
                if (!first)
                    sb.Append(ARRAY_DELIMITER);

                sb.AppendFormat("Depot: {0} Client: {1} Local: {2} Version: {3}",
                   spec.DepotPath, spec.ClientPath, spec.LocalPath, spec.Version);

                first = false;
            }
            sb.Append(RIGHT_BRACE);
            return sb.ToString();
        }

        public static string FileAndMetaListToString(List<FileAndMeta> a)
        {
            if (a == null)
                return NULL_STRING;

            StringBuilder sb = new StringBuilder();
            sb.Append(LEFT_BRACE);
            bool first = true;

            foreach (FileAndMeta fam in a)
            {
                if (!first)
                    sb.Append(ARRAY_DELIMITER);

                sb.AppendFormat("file: {0} meta: {1}", fam.File, fam.Meta);

                first = false;
            }
            sb.Append(RIGHT_BRACE);
            return sb.ToString();
        }

    }
}