using Google.Protobuf;
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Windows.Media.Imaging;
using Tango.BL.Entities;
using Tango.Core;
using Tango.Core.Helpers;
using Tango.Core.IO;
using Tango.Logging;
using Tango.PMR.Diagnostics;
using Tango.Serialization;

namespace Tango.Integration.Diagnostics
{
    /// <summary>
    /// Represents a Tango machine diagnostics file recorder capable of recording diagnostics data coming from the machine to a file.
    /// This file can then be played using the <see cref="DiagnosticsFilePlayer"/>.
    /// </summary>
    /// <seealso cref="Tango.Core.ExtendedObject" />
    /// <seealso cref="System.IDisposable" />
    public class DiagnosticsFileRecorder : ExtendedObject, IDisposable
    {
        private ConcurrentQueue<DataFileFrame> _frames; //Holds the queue of data frames ready to be written to file.
        private Thread _recordingThread; //Holds the recording thread.
        private TemporaryFile _tempDataFile; //Holds the temporary recording file name.
        private FileStream _dataFileStream; //Holds the temporary recording file stream.
        private TaskCompletionSource<object> _stopCompletionSource; //Holds the "Stop" async method completion source.
        private DiagnosticsTimeCodeChannel _timeCodeChannel; //Holds the diagnostics time code channel.
        private List<DiagnosticsFileEvent> _events;
        private Stopwatch _stopWatch; //Holds the stop watch for keeping tracks over frames time stamps.
        private DateTime _lastVideoPush;
        private List<BitmapSource> _videoFrames;

        #region Constructors

        public DiagnosticsFileRecorder()
        {
            _lastVideoPush = DateTime.Now;
            VideoFPS = 10;
            VideoQuality = 30;
        }

        #endregion

        #region Properties

        private bool _isRecording;
        /// <summary>
        /// Gets a value indicating whether the recorder is currently recording.
        /// </summary>
        public bool IsRecording
        {
            get { return _isRecording; }
            private set { _isRecording = value; RaisePropertyChangedAuto(); }
        }

        private long _totalFramesRecorded;
        /// <summary>
        /// Gets the total frames recorded.
        /// </summary>
        public long TotalFramesRecorded
        {
            get { return _totalFramesRecorded; }
            private set { _totalFramesRecorded = value; RaisePropertyChanged(nameof(TotalFramesRecorded)); }
        }

        private long _totalVideoFramesRecorded;
        /// <summary>
        /// Gets or sets the total video frames recorded.
        /// </summary>
        public long TotalVideoFramesRecorded
        {
            get { return _totalVideoFramesRecorded; }
            private set { _totalVideoFramesRecorded = value; RaisePropertyChangedAuto(); }
        }

        private int _videoQuality;
        /// <summary>
        /// Gets or sets the video quality.
        /// </summary>
        public int VideoQuality
        {
            get { return _videoQuality; }
            set { _videoQuality = value; RaisePropertyChangedAuto(); }
        }

        private long _totalBytesDataRecorded;
        /// <summary>
        /// Gets the total bytes recorded.
        /// </summary>
        public long TotalDataBytesRecorded
        {
            get { return _totalBytesDataRecorded; }
            private set { _totalBytesDataRecorded = value; RaisePropertyChanged(nameof(TotalDataBytesRecorded)); }
        }

        private long _totalBytesRecorded;
        /// <summary>
        /// Gets or sets the total bytes recorded.
        /// </summary>
        public long TotalBytesRecorded
        {
            get { return _totalBytesRecorded; }
            set { _totalBytesRecorded = value; RaisePropertyChangedAuto(); }
        }

        /// <summary>
        /// Gets the recording time.
        /// </summary>
        public TimeSpan RecordingTime
        {
            get { return _stopWatch != null ? _stopWatch.Elapsed : TimeSpan.Zero; }
        }

        /// <summary>
        /// Gets or sets the video recording frame rate.
        /// </summary>
        public int VideoFPS { get; set; }

        #endregion

        #region Public Methods

        /// <summary>
        /// Start recording. The actual recording will start only on the next <see cref="Write(PushDiagnosticsResponse)"/> call.
        /// </summary>
        public void Start()
        {
            if (!IsRecording)
            {
                if (_stopWatch != null)
                {
                    _stopWatch.Stop();
                    _stopWatch = null;
                }
                _tempDataFile = TemporaryManager.CreateFile();
                _frames = new ConcurrentQueue<DataFileFrame>();
                _events = new List<DiagnosticsFileEvent>();
                _timeCodeChannel = new DiagnosticsTimeCodeChannel();
                TotalDataBytesRecorded = 0;
                TotalFramesRecorded = 0;
                TotalVideoFramesRecorded = 0;
                TotalBytesRecorded = 0;

                _dataFileStream = _tempDataFile.CreateStream();

                IsRecording = true;
                _recordingThread = new Thread(RecordingThreadMethod);
                _recordingThread.IsBackground = true;
                _recordingThread.Start();
            }
        }

        /// <summary>
        /// Stop recording.
        /// </summary>
        /// <returns></returns>
        public Task Stop()
        {
            if (IsRecording)
            {
                IsRecording = false;
                _stopCompletionSource = new TaskCompletionSource<object>();
                return _stopCompletionSource.Task;
            }
            else
            {
                return Task.FromResult(new object());
            }
        }

        /// <summary>
        /// Writes a machine event to the diagnostics file.
        /// </summary>
        /// <param name="data">The data.</param>
        public void Write(MachinesEvent ev)
        {
            _events.Add(new DiagnosticsFileEvent(ev));
        }

        /// <summary>
        /// Writes a diagnostics packet to the recording.
        /// </summary>
        /// <param name="data">The data.</param>
        public void Write(StartDiagnosticsResponse data)
        {
            DataFileFrame frame = new DataFileFrame();
            frame.StartDiagnosticsResponse = data;
            Write(frame);
        }

        /// <summary>
        /// Writes the specified video frames. Each video frame is a different camera!
        /// </summary>
        /// <param name="videoFrames">The video frames.</param>
        public void Write(IEnumerable<BitmapSource> videoFrames)
        {
            if (!IsRecording) throw LogManager.Log(new InvalidOperationException("Please start the recorder before attempting to push data."));

            int milli = 1000 / VideoFPS;

            if (DateTime.Now >= _lastVideoPush.AddMilliseconds(milli))
            {
                _videoFrames = videoFrames.ToList();
                _lastVideoPush = DateTime.Now;
            }
        }

        /// <summary>
        /// Writes the specified data frame to the recording.
        /// </summary>
        /// <param name="frame">The frame.</param>
        /// <exception cref="InvalidOperationException">Please start the recorder before attempting to push data.</exception>
        public void Write(DataFileFrame frame)
        {
            if (!IsRecording) throw LogManager.Log(new InvalidOperationException("Please start the recorder before attempting to push data."));

            if (_stopWatch == null)
            {
                _stopWatch = new Stopwatch();
                _stopWatch.Start();
            }

            frame.Milliseconds = (int)_stopWatch.Elapsed.TotalMilliseconds;
            _frames.Enqueue(frame);

            RaisePropertyChanged(nameof(RecordingTime));
        }

        /// <summary>
        /// Saves the current recording to the specified file. (Use only after calling "Stop").
        /// </summary>
        /// <param name="fileName">Name of the file.</param>
        /// <returns></returns>
        /// <exception cref="InvalidOperationException">
        /// Cannot save a recording file while recording.
        /// or
        /// No data was captured during recording time. Cannot save recording
        /// </exception>
        public Task Save(String fileName)
        {
            if (IsRecording)
            {
                throw LogManager.Log(new InvalidOperationException("Cannot save a recording file while recording."));
            }

            if (_timeCodeChannel.Frames.Count == 0)
            {
                throw LogManager.Log(new InvalidOperationException("No data was captured during recording time. Cannot save recording"));
            }

            return Task.Factory.StartNew(() =>
            {

                BinaryDataSerializer serializer = new BinaryDataSerializer();
                _timeCodeChannel.Events = _events;
                byte[] timeCodeData = serializer.SerializeToBytes(_timeCodeChannel);

                using (FileStream fs = new FileStream(fileName, FileMode.Create))
                {
                    BinaryWriter writer = new BinaryWriter(fs);
                    writer.Write(timeCodeData.Length);
                    writer.Write(timeCodeData, 0, timeCodeData.Length);

                    using (Stream dataFileStream = _tempDataFile.CreateStream())
                    {
                        dataFileStream.CopyTo(fs);
                    }
                }

            });
        }

        #endregion

        #region Recording Thread

        /// <summary>
        /// Handles the recording thread.
        /// </summary>
        private void RecordingThreadMethod()
        {
            while (IsRecording)
            {
                while (_frames.Count > 0)
                {
                    DataFileFrame frame = null;
                    if (_frames.TryDequeue(out frame))
                    {
                        DiagnosticsTimeCodeChannelFrame timeCodeFrame = new DiagnosticsTimeCodeChannelFrame();
                        timeCodeFrame.Position = TotalDataBytesRecorded;

                        if (_videoFrames != null && _videoFrames.Count > 0)
                        {
                            foreach (var videoFrame in _videoFrames)
                            {
                                if (videoFrame != null)
                                {
                                    var bytes = ByteString.CopyFrom(videoFrame.ToJpegBytes(VideoQuality));
                                    frame.VideoFrames.Add(bytes);
                                    TotalBytesRecorded += bytes.Length;
                                }
                            }

                            _videoFrames = null;
                            TotalVideoFramesRecorded++;
                        }

                        byte[] data = frame.ToBytes();

                        _dataFileStream.Write(data, 0, data.Length);

                        TotalFramesRecorded++;
                        TotalDataBytesRecorded += data.Length;
                        TotalBytesRecorded += data.Length;

                        timeCodeFrame.Milliseconds = frame.Milliseconds;
                        timeCodeFrame.FrameLength = data.Length;

                        _timeCodeChannel.Frames.Add(timeCodeFrame);
                    }
                }

                Thread.Sleep(10);
            }

            _dataFileStream.Dispose();

            if (_stopCompletionSource != null)
            {
                _stopCompletionSource.SetResult(new object());
            }
        }

        #endregion

        #region IDisposable

        /// <summary>
        /// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
        /// </summary>
        public void Dispose()
        {
            _tempDataFile.Delete();
        }

        #endregion
    }
}