using System;
using System.Globalization;
using System.IO;
using System.Text;
using BizHawk.Common;

using BizHawk.Emulation.Common;

namespace BizHawk.Client.Common
{
	public class Movie : IMovie
	{
		#region Constructors

		public Movie(string filename, bool startsFromSavestate = false)
			: this(startsFromSavestate)
		{
			Header.Rerecords = 0;
			Filename = filename;
			Loaded = !String.IsNullOrWhiteSpace(filename);
		}

		public Movie(bool startsFromSavestate = false)
		{
			Header = new MovieHeader();
			Filename = String.Empty;
			_preloadFramecount = 0;
			Header.StartsFromSavestate = startsFromSavestate;
			
			IsCountingRerecords = true;
			_mode = Moviemode.Inactive;
			MakeBackup = true;
		}

		#endregion

		#region Properties

		public IMovieHeader Header { get; private set; }

		public bool MakeBackup { get; set; }
		public string Filename { get; set; }
		public bool IsCountingRerecords { get; set; }
		
		public bool Loaded { get; private set; }

		public int InputLogLength
		{
			get { return _log.Length; }
		}

		public double FrameCount
		{
			get
			{
				if (_loopOffset.HasValue)
				{
					return double.PositiveInfinity;
				}
				else if (Loaded)
				{
					return _log.Length;
				}
				else
				{
					return _preloadFramecount;
				}
			}
		}

		#endregion

		#region Mode API

		public bool IsPlaying
		{
			get { return _mode == Moviemode.Play || _mode == Moviemode.Finished; }
		}

		public bool IsRecording
		{
			get { return _mode == Moviemode.Record; }
		}

		public bool IsActive
		{
			get { return _mode != Moviemode.Inactive; }
		}

		public bool IsFinished
		{
			get { return _mode == Moviemode.Finished; }
		}

		public bool Changes
		{
			get { return _changes; }
		}

		public void StartNewRecording()
		{
			Global.Emulator.ClearSaveRam();
			_mode = Moviemode.Record;
			if (Global.Config.EnableBackupMovies && MakeBackup && _log.Length > 0)
			{
				SaveBackup();
				MakeBackup = false;
			}

			_log.Clear();
		}

		public void StartNewPlayback()
		{
			Global.Emulator.ClearSaveRam();
			_mode = Moviemode.Play;
		}

		public void SwitchToRecord()
		{
			_mode = Moviemode.Record;
		}

		public void SwitchToPlay()
		{
			_mode = Moviemode.Play;
			Save();
		}

		public void Stop(bool saveChanges = true)
		{
			if (saveChanges)
			{
				if (_mode == Moviemode.Record || _changes)
				{
					Save();
				}
			}

			_changes = false;
			_mode = Moviemode.Inactive;
		}

		/// <summary>
		/// If a movie is in playback mode, this will set it to movie finished
		/// </summary>
		private void Finish()
		{
			if (_mode == Moviemode.Play)
			{
				_mode = Moviemode.Finished;
			}
		}
		
		#endregion

		#region Public File Handling

		public void SaveAs(string path)
		{
			Filename = path;
			if (!Loaded)
			{
				return;
			}

			var directory_info = new FileInfo(Filename).Directory;
			if (directory_info != null)
			{
				Directory.CreateDirectory(directory_info.FullName);
			}

			Write(Filename);
		}

		public void Save()
		{
			if (!Loaded || String.IsNullOrWhiteSpace(Filename))
			{
				return;
			}

			SaveAs(Filename);
			_changes = false;
		}

		public void SaveBackup()
		{
			if (!Loaded || String.IsNullOrWhiteSpace(Filename))
			{
				return;
			}

			var backupName = Filename;
			backupName = backupName.Insert(Filename.LastIndexOf("."), String.Format(".{0:yyyy-MM-dd HH.mm.ss}", DateTime.Now));
			backupName = Path.Combine(Global.Config.PathEntries["Global", "Movie backups"].Path, Path.GetFileName(backupName) ?? String.Empty);

			var directory_info = new FileInfo(backupName).Directory;
			if (directory_info != null)
			{
				Directory.CreateDirectory(directory_info.FullName);
			}

			Write(backupName);
		}

		/// <summary>
		/// Load Header information only for displaying file information in dialogs such as play movie
		/// </summary>
		public bool PreLoadText(HawkFile hawkFile)
		{
			Loaded = false;
			var file = new FileInfo(hawkFile.CanonicalFullPath);

			if (file.Exists == false)
			{
				return false;
			}
			else
			{
				Header.Clear();
				_log.Clear();
			}

			var origStreamPosn = hawkFile.GetStream().Position; 
			hawkFile.GetStream().Position = 0; // Reset to start
			var sr = new StreamReader(hawkFile.GetStream());
			
			// No using block because we're sharing the stream and need to give it back undisposed.
			if (!sr.EndOfStream)
			{
				string line;
				while ((line = sr.ReadLine()) != null)
				{
					if (line.Contains("LoopOffset"))
					{
						try
						{
							_loopOffset = int.Parse(line.Split(new[] { ' ' }, 2)[1]);
						}
						catch (Exception)
						{
							continue;
						}
					}
					else if (String.IsNullOrWhiteSpace(line) || Header.ParseLineFromFile(line))
					{
						continue;
					}
					else if (line.StartsWith("|"))
					{
						var frames = sr.ReadToEnd();
						var length = line.Length;

						// Account for line breaks of either size.
						if (frames.IndexOf("\r\n") != -1)
						{
							length++;
						}

						length++;
						_preloadFramecount = (frames.Length / length) + 1; // Count the remaining frames and the current one.
						break;
					}
					else
					{
						Header.Comments.Add(line);
					}
				}
			}

			hawkFile.GetStream().Position = origStreamPosn;

			return true;
		}

		public bool Load()
		{
			var file = new FileInfo(Filename);
			if (file.Exists == false)
			{
				Loaded = false;
				return false;
			}

			return LoadText();
		}

		#endregion

		#region Public Log Editing

		public string GetInput(int frame)
		{
			if (frame < _log.Length)
			{
				if (frame >= 0)
				{
					int getframe;

					if (_loopOffset.HasValue)
					{
						if (frame < _log.Length)
						{
							getframe = frame;
						}
						else
						{
							getframe = ((frame - _loopOffset.Value) % (_log.Length - _loopOffset.Value)) + _loopOffset.Value;
						}
					}
					else
					{
						getframe = frame;
					}

					return _log[getframe];
				}
				else
				{
					return String.Empty;
				}
			}
			else
			{
				Finish();
				return String.Empty;
			}
		}

		public void ClearFrame(int frame)
		{
			_log.SetFrameAt(frame, new MnemonicsGenerator().EmptyMnemonic);
			_changes = true;
		}

		public void AppendFrame(IController source)
		{
			MnemonicsGenerator mg = new MnemonicsGenerator();
			mg.SetSource(source);
			_log.AppendFrame(mg.GetControllersAsMnemonic());
			_changes = true;
		}

		public void Truncate(int frame)
		{
			_log.TruncateMovie(frame);
			_log.TruncateStates(frame);
			_changes = true;
		}

		#endregion

		#region Public Misc Methods

		public void PokeFrame(int frame, IController source)
		{
			MnemonicsGenerator mg = new MnemonicsGenerator();
			mg.SetSource(source);

			_changes = true;
			_log.SetFrameAt(frame, mg.GetControllersAsMnemonic());
		}

		public void RecordFrame(int frame, IController source)
		{
			// Note: Truncation here instead of loadstate will make VBA style loadstates
			// (Where an entire movie is loaded then truncated on the next frame
			// this allows users to restore a movie with any savestate from that "timeline"
			if (Global.Config.VBAStyleMovieLoadState)
			{
				if (Global.Emulator.Frame < _log.Length)
				{
					_log.TruncateMovie(Global.Emulator.Frame);
				}
			}

			MnemonicsGenerator mg = new MnemonicsGenerator();
			mg.SetSource(source);

			_changes = true;
			_log.SetFrameAt(frame, mg.GetControllersAsMnemonic());
		}

		public string GetInputLog()
		{
			var sb = new StringBuilder();

			sb.AppendLine("[Input]");

			foreach (var record in _log)
			{
				sb.AppendLine(record);
			}

			sb.AppendLine("[/Input]");

			return sb.ToString();
		}

		public bool ExtractInputLog(TextReader reader, out string errorMessage)
		{
			errorMessage = String.Empty;
			int? stateFrame = null;
			
			// We are in record mode so replace the movie log with the one from the savestate
			if (!Global.MovieSession.MultiTrack.IsActive)
			{
				if (Global.Config.EnableBackupMovies && MakeBackup && _log.Length > 0)
				{
					SaveBackup();
					MakeBackup = false;
				}

				_log.Clear();
				while (true)
				{
					var line = reader.ReadLine();
					if (line == null)
					{
						break;
					}
					else if (line.Trim() == String.Empty)
					{
						continue;
					}
					else if (line == "[Input]")
					{
						continue;
					}
					else if (line == "[/Input]")
					{
						break;
					}
					else if (line.Contains("Frame 0x")) // NES stores frame count in hex, yay
					{
						var strs = line.Split('x');
						try
						{
							stateFrame = int.Parse(strs[1], NumberStyles.HexNumber);
						}
						catch
						{
							errorMessage = "Savestate Frame number failed to parse";
							return false;
						}
					}
					else if (line.Contains("Frame "))
					{
						var strs = line.Split(' ');
						try
						{
							stateFrame = int.Parse(strs[1]);
						}
						catch
						{
							errorMessage = "Savestate Frame number failed to parse";
							return false;
						}
					}
					else if (line[0] == '|')
					{
						_log.AppendFrame(line);
					}
				}
			}
			else
			{
				int i = 0;
				while (true)
				{
					var line = reader.ReadLine();
					if (line == null)
					{
						break;
					}
					else if (line.Trim() == string.Empty)
					{
						continue;
					}
					else if (line == "[Input]")
					{
						continue;
					}
					else if (line == "[/Input]")
					{
						break;
					}
					else if (line.Contains("Frame 0x")) // NES stores frame count in hex, yay
					{
						var strs = line.Split('x');
						try
						{
							stateFrame = int.Parse(strs[1], NumberStyles.HexNumber);
						}
						catch
						{
							errorMessage = "Savestate Frame number failed to parse";
							return false;
						}
					}
					else if (line.Contains("Frame "))
					{
						var strs = line.Split(' ');
						try
						{
							stateFrame = int.Parse(strs[1]);
						}
						catch
						{
							errorMessage = "Savestate Frame number failed to parse";
							return false;
						}
					}
					else if (line.StartsWith("|"))
					{
						_log.SetFrameAt(i, line);
						i++;
					}
				}
			}

			if (stateFrame == null)
			{
				errorMessage = "Savestate Frame number failed to parse";
			}

			var stateFramei = (int)stateFrame;

			if (stateFramei > 0 && stateFramei < _log.Length)
			{
				if (!Global.Config.VBAStyleMovieLoadState)
				{
					_log.TruncateStates(stateFramei);
					_log.TruncateMovie(stateFramei);
				}
			}
			else if (stateFramei > _log.Length) // Post movie savestate
			{
				if (!Global.Config.VBAStyleMovieLoadState)
				{
					_log.TruncateStates(_log.Length);
					_log.TruncateMovie(_log.Length);
				}

				_mode = Moviemode.Finished;
			}

			if (IsCountingRerecords)
			{
				Header.Rerecords++;
			}

			return true;
		}

		public TimeSpan Time
		{
			get
			{
				double dblseconds = GetSeconds(Loaded ? _log.Length : _preloadFramecount);
				int seconds = (int)(dblseconds % 60);
				int days = seconds / 86400;
				int hours = seconds / 3600;
				int minutes = (seconds / 60) % 60;
				int milliseconds = (int)((dblseconds - (double)seconds) * 1000);
				return new TimeSpan(days, hours, minutes, seconds, milliseconds);
			}
		}

		public bool CheckTimeLines(TextReader reader, out string errorMessage)
		{
			// This function will compare the movie data to the savestate movie data to see if they match
			errorMessage = String.Empty;
			var log = new MovieLog();
			int stateFrame = 0;
			while (true)
			{
				var line = reader.ReadLine();
				if (line == null)
				{
					return false;
				}
				else if (line.Trim() == string.Empty)
				{
					continue;
				}
				else if (line.Contains("Frame 0x")) // NES stores frame count in hex, yay
				{
					var strs = line.Split('x');
					try
					{
						stateFrame = int.Parse(strs[1], NumberStyles.HexNumber);
					}
					catch
					{
						errorMessage = "Savestate Frame number failed to parse";
						return false;
					}
				}
				else if (line.Contains("Frame "))
				{
					var strs = line.Split(' ');
					try
					{
						stateFrame = int.Parse(strs[1]);
					}
					catch
					{
						errorMessage = "Savestate Frame number failed to parse";
						return false;
					}
				}
				else if (line == "[Input]")
				{
					continue;
				}
				else if (line == "[/Input]")
				{
					break;
				}
				else if (line[0] == '|')
				{
					log.AppendFrame(line);
				}
			}

			if (stateFrame == 0)
			{
				stateFrame = log.Length;  // In case the frame count failed to parse, revert to using the entire state input log
			}

			if (_log.Length < stateFrame)
			{
				if (IsFinished)
				{
					return true;
				}
				else
				{
					errorMessage = "The savestate is from frame "
						+ log.Length
						+ " which is greater than the current movie length of "
						+ _log.Length;
					return false;
				}
			}

			for (var i = 0; i < stateFrame; i++)
			{
				if (_log[i] != log[i])
				{
					errorMessage = "The savestate input does not match the movie input at frame "
						+ (i + 1)
						+ ".";
					return false;
				}
			}

			if (stateFrame > log.Length) // stateFrame is greater than state input log, so movie finished mode
			{
				if (_mode == Moviemode.Play || _mode == Moviemode.Finished)
				{
					_mode = Moviemode.Finished;
					return true;
				}
				else
				{
					return false;
				}
			}
			else if (_mode == Moviemode.Finished)
			{
				_mode = Moviemode.Play;
			}

			return true;
		}

		#endregion

		#region Private Vars

		private readonly MovieLog _log = new MovieLog();
		private enum Moviemode { Inactive, Play, Record, Finished };
		private Moviemode _mode = Moviemode.Inactive;
		private int _preloadFramecount; // Not a a reliable number, used for preloading (when no log has yet been loaded), this is only for quick stat compilation for dialogs such as play movie
		private bool _changes;
		private int? _loopOffset;
		private readonly PlatformFrameRates _frameRates = new PlatformFrameRates();

		#endregion

		#region Helpers

		private void Write(string fn)
		{
			using (var fs = new FileStream(fn, FileMode.Create, FileAccess.Write, FileShare.Read))
			{
				WriteText(fs);
			}
		}

		private void WriteText(Stream stream)
		{
			using (var sw = new StreamWriter(stream))
			{
				sw.Write(Header.ToString());

				// TODO: clean this up
				if (_loopOffset.HasValue)
				{
					sw.WriteLine("LoopOffset " + _loopOffset);
				}

				foreach (var input in _log)
				{
					sw.WriteLine(input);
				}
			}
		}

		private bool LoadText()
		{
			var file = new FileInfo(Filename);

			if (file.Exists == false)
			{
				Loaded = false;
				return false;
			}
			else
			{
				Header.Clear();
				_log.Clear();
			}

			using (var sr = file.OpenText())
			{
				string line;

				while ((line = sr.ReadLine()) != null)
				{
					if (line == String.Empty)
					{
						continue;
					}

					if (line.Contains("LoopOffset"))
					{
						try
						{
							_loopOffset = int.Parse(line.Split(new[] { ' ' }, 2)[1]);
						}
						catch (Exception)
						{
							continue;
						}
					}
					else if (Header.ParseLineFromFile(line))
					{
						continue;
					}
					else if (line.StartsWith("|"))
					{
						_log.AppendFrame(line);
					}
					else
					{
						Header.Comments.Add(line);
					}
				}
			}

			Loaded = true;
			return true;
		}

		private static string MakeDigits(int num)
		{
			return num < 10 ? "0" + num : num.ToString();
		}

		private double GetSeconds(int frameCount)
		{
			double frames = frameCount;
			
			if (frames < 1)
			{
				return 0;
			}

			var system = Header[HeaderKeys.PLATFORM];
			var pal = Header.ContainsKey(HeaderKeys.PAL) &&
				Header[HeaderKeys.PAL] == "1";

			return frames / _frameRates[system, pal];
		}

		public double Fps
		{
			get
			{
				var system = Header[HeaderKeys.PLATFORM];
				var pal = Header.ContainsKey(HeaderKeys.PAL) &&
					Header[HeaderKeys.PAL] == "1";

				return _frameRates[system, pal];
			}
		}

		#endregion
	}
}