using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Globalization;
using System.IO;
using System.Linq;

using BizHawk.Emulation.Common;
using BizHawk.Emulation.Common.IEmulatorExtensions;

namespace BizHawk.Client.Common
{
	public sealed partial class TasMovie : Bk2Movie, INotifyPropertyChanged
	{
		private readonly Bk2MnemonicConstants _mnemonics = new Bk2MnemonicConstants();
		private readonly IStateManager _stateManager;
		private readonly TasLagLog _lagLog = new TasLagLog();
		private readonly Dictionary<int, IController> _inputStateCache = new Dictionary<int, IController>();
		private BackgroundWorker _progressReportWorker;

		public readonly IStringLog VerificationLog = StringLogUtil.MakeStringLog(); // For movies that do not begin with power-on, this is the input required to get into the initial state
		public readonly TasBranchCollection Branches = new TasBranchCollection();
		public readonly TasSession Session;

		public new const string Extension = "tasproj";
		public const string DefaultProjectName = "default";
		public string NewBranchText { get; set; } = "";
		public int LastEditedFrame { get; set; } = -1;
		public bool LastPositionStable { get; set; } = true;
		public TasMovieMarkerList Markers { get; private set; }
		public bool BindMarkersToInput { get; set; }
		public bool UseInputCache { get; set; }
		public int CurrentBranch { get; set; }

		public TasLagLog TasLagLog => _lagLog;
		public IStringLog InputLog => Log;
		public int BranchCount => Branches.Count;
		public int LastStatedFrame => _stateManager.LastStatedFrame;
		public override string PreferredExtension => Extension;
		public IStateManager TasStateManager => _stateManager;

		public TasMovieRecord this[int index] => new TasMovieRecord
		{
			// State = StateManager[index],
			HasState = _stateManager.HasState(index),
			LogEntry = GetInputLogEntry(index),
			Lagged = _lagLog[index + 1],
			WasLagged = _lagLog.History(index + 1)
		};

	    public TasMovie(string path, bool startsFromSavestate = false, BackgroundWorker progressReportWorker = null)
			: base(path)
		{
			// TODO: how to call the default constructor AND the base(path) constructor?  And is base(path) calling base() ?
			_progressReportWorker = progressReportWorker;
			if (!Global.Emulator.HasSavestates())
			{
				throw new InvalidOperationException($"Cannot create a {nameof(TasMovie)} against a core that does not implement {nameof(IStatable)}");
			}

			ChangeLog = new TasMovieChangeLog(this);
			_stateManager = new TasStateManager(this);
			Session = new TasSession(this);
			Header[HeaderKeys.MOVIEVERSION] = "BizHawk v2.0 Tasproj v1.0";
			Markers = new TasMovieMarkerList(this);
			Markers.CollectionChanged += Markers_CollectionChanged;
			Markers.Add(0, startsFromSavestate ? "Savestate" : "Power on");
			BindMarkersToInput = false;
			CurrentBranch = -1;
		}

		public TasMovie(bool startsFromSavestate = false, BackgroundWorker progressReportWorker = null)
		{
			_progressReportWorker = progressReportWorker;
			if (!Global.Emulator.HasSavestates())
			{
				throw new InvalidOperationException($"Cannot create a {nameof(TasMovie)} against a core that does not implement {nameof(IStatable)}");
			}

			ChangeLog = new TasMovieChangeLog(this);
			_stateManager = new TasStateManager(this);
			Session = new TasSession(this);
			Header[HeaderKeys.MOVIEVERSION] = "BizHawk v2.0 Tasproj v1.0";
			Markers = new TasMovieMarkerList(this);
			Markers.CollectionChanged += Markers_CollectionChanged;
			Markers.Add(0, startsFromSavestate ? "Savestate" : "Power on");
			BindMarkersToInput = false;
			CurrentBranch = -1;
		}

		public void NewBGWorker(BackgroundWorker newWorker)
		{
			_progressReportWorker = newWorker;
		}

		public void ReportProgress(double percent)
		{
			if (percent > 100d)
			{
				return;
			}

			_progressReportWorker?.ReportProgress((int)percent);
		}

		// TODO: use LogGenerators rather than string comparisons
		private int? DivergentPoint(IStringLog currentLog, IStringLog newLog)
		{
			int max = newLog.Count;
			if (currentLog.Count < newLog.Count)
			{
				max = currentLog.Count;
			}

			for (int i = 0; i < max; i++)
			{
				if (newLog[i] != currentLog[i])
				{
					return i;
				}
			}

			return null;
		}

		public override void StartNewRecording()
		{
			ClearTasprojExtras();
			Markers.Add(0, StartsFromSavestate ? "Savestate" : "Power on");
			ChangeLog = new TasMovieChangeLog(this);

			base.StartNewRecording();
		}

		public override void SwitchToPlay()
		{
			Mode = Moviemode.Play;
		}

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

		/// <summary>
		/// Removes lag log and greenzone after this frame
		/// </summary>
		/// <param name="frame">The last frame that can be valid.</param>
		private void InvalidateAfter(int frame)
		{
			var anyInvalidated = _lagLog.RemoveFrom(frame);
			_stateManager.Invalidate(frame + 1);
			Changes = anyInvalidated;
			LastEditedFrame = frame;

			if (anyInvalidated && Global.MovieSession.Movie.IsCountingRerecords)
			{
				Rerecords++;
			}
		}

		/// <summary>
		/// Returns the mnemonic value for boolean buttons, and actual value for floats,
		/// for a given frame and button.
		/// </summary>
		public string DisplayValue(int frame, string buttonName)
		{
			if (UseInputCache && _inputStateCache.ContainsKey(frame))
			{
				return CreateDisplayValueForButton(_inputStateCache[frame], buttonName);
			}

			var adapter = GetInputState(frame);

			if (UseInputCache)
			{
				_inputStateCache.Add(frame, adapter);
			}

			return CreateDisplayValueForButton(adapter, buttonName);
		}

		public void FlushInputCache()
		{
			_inputStateCache.Clear();
		}

		public string CreateDisplayValueForButton(IController adapter, string buttonName)
		{
			if (adapter.Definition.BoolButtons.Contains(buttonName))
			{
				return adapter.IsPressed(buttonName)
					? _mnemonics[buttonName].ToString()
					: "";
			}

			if (adapter.Definition.FloatControls.Contains(buttonName))
			{
				return adapter.GetFloat(buttonName).ToString();
			}

			return "!";
		}

		public bool BoolIsPressed(int frame, string buttonName)
		{
			return ((Bk2ControllerAdapter)GetInputState(frame))
				.IsPressed(buttonName);
		}

		public float GetFloatState(int frame, string buttonName)
		{
			return ((Bk2ControllerAdapter)GetInputState(frame))
				.GetFloat(buttonName);
		}

		public void ClearGreenzone()
		{
			if (_stateManager.Any())
			{
				_stateManager.ClearStateHistory();
				Changes = true;
			}
		}

		public void GreenzoneCurrentFrame()
		{
			// todo: this isn't working quite right when autorestore is off and we're editing while seeking
			// but accounting for that requires access to Mainform.IsSeeking
			if (Global.Emulator.Frame > LastEditedFrame)
			{
				// emulated a new frame, current editing segment may change now. taseditor logic
				LastPositionStable = false;
			}

			_lagLog[Global.Emulator.Frame] = Global.Emulator.AsInputPollable().IsLagFrame;

			if (!_stateManager.HasState(Global.Emulator.Frame))
			{
				_stateManager.Capture(Global.Emulator.Frame == LastEditedFrame - 1);
			}
		}

		public void ClearLagLog()
		{
			_lagLog.Clear();
		}

		public void DeleteLogBefore(int frame)
		{
			if (frame < Log.Count)
			{
				Log.RemoveRange(0, frame);
			}
		}

		public void CopyLog(IEnumerable<string> log)
		{
			Log.Clear();
			foreach (var entry in log)
			{
				Log.Add(entry);
			}
		}

		public void CopyVerificationLog(IEnumerable<string> log)
		{
			foreach (string entry in log)
			{
				VerificationLog.Add(entry);
			}
		}

		public IStringLog GetLogEntries()
		{
			return Log;
		}

		private int? _timelineBranchFrame = null;

		// TODO: this is 99% copy pasting of bad code
		public override bool ExtractInputLog(TextReader reader, out string errorMessage)
		{
			errorMessage = "";
			int? stateFrame = null;

			var newLog = new List<string>();

			// We are in record mode so replace the movie log with the one from the savestate
			if (!Global.MovieSession.MultiTrack.IsActive)
			{
				_timelineBranchFrame = null;

				if (Global.Config.EnableBackupMovies && MakeBackup && Log.Count != 0)
				{
					SaveBackup();
					MakeBackup = false;
				}

				int counter = 0;
				while (true)
				{
					var line = reader.ReadLine();
					if (string.IsNullOrEmpty(line))
					{
						break;
					}

					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("LogKey:"))
					{
						LogKey = line.Replace("LogKey:", "");
					}
					else if (line[0] == '|')
					{
						newLog.Add(line);
						if (!_timelineBranchFrame.HasValue && counter < Log.Count && line != Log[counter])
						{
							_timelineBranchFrame = counter;
						}

						counter++;
					}
				}

				Log.Clear();
				Log.AddRange(newLog);
			}
			else // Multitrack mode
			{
				// TODO: consider TimelineBranchFrame here, my thinking is that there's never a scenario to invalidate state/lag data during multitrack
				var i = 0;
				while (true)
				{
					var line = reader.ReadLine();
					if (line == null)
					{
						break;
					}

					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("LogKey:"))
					{
						LogKey = line.Replace("LogKey:", "");
					}
					else if (line.StartsWith("|"))
					{
						SetFrame(i, line);
						i++;
					}
				}
			}

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

			var stateFramei = stateFrame ?? 0;

			if (stateFramei > 0 && stateFramei < Log.Count)
			{
				if (!Global.Config.VBAStyleMovieLoadState)
				{
					Truncate(stateFramei);
				}
			}
			else if (stateFramei > Log.Count) // Post movie savestate
			{
				if (!Global.Config.VBAStyleMovieLoadState)
				{
					Truncate(Log.Count);
				}

				Mode = Moviemode.Finished;
			}

			if (IsCountingRerecords)
			{
				Rerecords++;
			}

			if (_timelineBranchFrame.HasValue)
			{
				_lagLog.RemoveFrom(_timelineBranchFrame.Value);
				TasStateManager.Invalidate(_timelineBranchFrame.Value);
			}

			return true;
		}

		#region Branches

		public TasBranch GetBranch(int index)
		{
			if (index >= Branches.Count || index < 0)
			{
				return null;
			}

			return Branches[index];
		}

		public TasBranch GetBranch(Guid id)
		{
			return Branches.SingleOrDefault(b => b.UniqueIdentifier == id);
		}

		public int BranchHashByIndex(int index)
		{
			if (index >= Branches.Count)
			{
				return -1;
			}

			return Branches[index].UniqueIdentifier.GetHashCode();
		}

		public int BranchIndexByHash(int hash)
		{
			TasBranch branch = Branches.SingleOrDefault(b => b.UniqueIdentifier.GetHashCode() == hash);
			if (branch == null)
			{
				return -1;
			}

			return Branches.IndexOf(branch);
		}

		public int BranchIndexByFrame(int frame)
		{
			TasBranch branch = Branches
				.Where(b => b.Frame == frame)
				.OrderByDescending(b => b.TimeStamp)
				.FirstOrDefault();

			if (branch == null)
			{
				return -1;
			}

			return Branches.IndexOf(branch);
		}

		public void AddBranch(TasBranch branch)
		{
			Branches.Add(branch);
			Changes = true;
		}

		public void RemoveBranch(TasBranch branch)
		{
			Branches.Remove(branch);
			Changes = true;
		}

		public void LoadBranch(TasBranch branch)
		{
			int? divergentPoint = DivergentPoint(Log, branch.InputLog);

			Log?.Dispose();
			Log = branch.InputLog.Clone();

			if (divergentPoint.HasValue)
			{
				InvalidateAfter(divergentPoint.Value);
			}
			else
			{
				InvalidateAfter(branch.InputLog.Count);
			}
			
			if (BindMarkersToInput) // pretty critical not to erase them
			{
				Markers = branch.Markers;
			}

			Changes = true;
		}

		public void UpdateBranch(TasBranch old, TasBranch newBranch)
		{
			int index = Branches.IndexOf(old);
			newBranch.UniqueIdentifier = old.UniqueIdentifier;
			if (newBranch.UserText == "")
			{
				newBranch.UserText = old.UserText;
			}

			Branches[index] = newBranch;
			Changes = true;
		}

		public void SwapBranches(int b1, int b2)
		{
			TasBranch branch = Branches[b1];

			if (b2 >= Branches.Count)
			{
				b2 = Branches.Count - 1;
			}

			Branches.Remove(branch);
			Branches.Insert(b2, branch);
			Changes = true;
		}

		#endregion

		#region Events and Handlers

		public event PropertyChangedEventHandler PropertyChanged;

		private bool _changes;
		public override bool Changes
		{
			get
			{
				return _changes;
			}

			protected set
			{
				if (_changes != value)
				{
					_changes = value;
					OnPropertyChanged("Changes");
				}
			}
		}

		// This event is Raised only when Changes is TOGGLED.
		private void OnPropertyChanged(string propertyName)
		{
			// Raising the event when FirstName or LastName property value changed
			PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
		}

		private void Markers_CollectionChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
		{
			Changes = true;
		}

		public void ClearChanges()
		{
			Changes = false;
		}

		public void FlagChanges()
		{
			Changes = true;
		}

		#endregion
	}
}