using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.ComponentModel;
using System.Windows.Input;
using System.Windows;
using BuzzGUI.Common;
using PropertyChanged;
using System.IO;
using System.Threading.Tasks;
using System.Diagnostics;
using BuzzGUI.Interfaces;

namespace BuzzGUI.MachineView.MDBTab
{
	public class MDBTabVM : INotifyPropertyChanged
	{
		MachineView view;
		static string mdbRoot = System.IO.Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments), "Buzz\\MDB");
		static string jsonPath = System.IO.Path.Combine(mdbRoot, "mdb.json.zip");
		static string machinesPath = System.IO.Path.Combine(mdbRoot, "mdb_machines.zip");
		static string gearPath = System.IO.Path.Combine(mdbRoot, "Gear");
		static MDB.Database database;
		
		HashSet<string> InstalledMachineSet { get; set; }

		public ICommand DownloadMDBCommand { get; private set; }

		public Visibility DownloadVisibility { get; set; }
		public int ProgressBarValue { get; set; }
		public Visibility ProgressBarVisibility { get {	return (ProgressBarValue != 0 && ProgressBarValue != 100) ? Visibility.Visible : Visibility.Collapsed; } }
		public bool IsDownloadButtonEnabled { get; set; }
		public bool IsListBoxEnabled { get; set; }

		public enum MachineFilterGroups { All, Generator, Effect, Control };
		public MachineFilterGroups VisibleMachines { get; set; }
		public string Filter { get; set; }

		Task loadDatabaseTask;
		bool initialized;
		bool unzip;
		bool failed;

		bool Match(InstrumentType t, MachineFilterGroups g)
		{
			if (g == MachineFilterGroups.All) return true;
			switch (t)
			{
				case InstrumentType.Generator: return g == MachineFilterGroups.Generator;
				case InstrumentType.Effect: return g == MachineFilterGroups.Effect;
				case InstrumentType.Control: return g == MachineFilterGroups.Control;
				default: return false;
			}
		}

		public IEnumerable<MachineListItemVM> Machines
		{
			get
			{
				if (failed) return null;

				if (!File.Exists(jsonPath) || new FileInfo(jsonPath).Length == 0)
				{
					DownloadVisibility = Visibility.Visible;
					return null;
				}

				if (database == null)
				{
					DownloadVisibility = Visibility.Collapsed;
					LoadDatabase();
					return null;
				}

				if (!initialized)
					return null;

				IsListBoxEnabled = true;

				return database.MachineDLLs
					.Where(d => !InstalledMachineSet.Contains(d.Filename.ToLowerInvariant())
						&& (Filter.Length == 0 || (d.Filename.IndexOf(Filter, 0, StringComparison.OrdinalIgnoreCase) != -1))
						&& Global.Buzz.MachineDLLs.ContainsKey(d.Filename))
					.OrderBy(d => d.Filename.ToLowerInvariant())
					.Select(d => new MachineListItemVM(Global.Buzz.MachineDLLs[d.Filename], d, gearPath))
					.Where(i => Match(i.Instrument.Type, VisibleMachines));
			}
		}

		public MDBTabVM(MachineView view)
		{
			this.view = view;
			view.PropertyChanged += view_PropertyChanged;
			IsDownloadButtonEnabled = true;
			IsListBoxEnabled = false;
			DownloadVisibility = Visibility.Collapsed;
			VisibleMachines = MachineFilterGroups.All;
			Filter = "";
			InstalledMachineSet = new HashSet<string>();

			DownloadMDBCommand = new SimpleCommand
			{
				CanExecuteDelegate = x => true,
				ExecuteDelegate = x => 
				{
					Download();
				}
			};

			if (Global.Buzz.Instruments.Count > 0)
				Update();
		}

		public void Update()
		{
			InstalledMachineSet = Global.Buzz.Instruments.Where(i => i.Name.Length == 0).Select(i => i.MachineDLL.Name.ToLowerInvariant()).ToHashSet();

			if (loadDatabaseTask != null)
				loadDatabaseTask.Wait();

			AddDLLs();

		}

		void AddDLLs()
		{
			if (database == null)
				return;

			database.MachineDLLs.Where(d => !InstalledMachineSet.Contains(d.Filename.ToLowerInvariant())).Run(d =>
			{
				Global.Buzz.AddMachineDLL(
					System.IO.Path.Combine(gearPath, System.IO.Path.Combine(d.GearDirectory, d.Filename + ".dll")),
					d.GearDirectory == "Generators" ? MachineType.Generator : MachineType.Effect);
			});

			initialized = true;
			PropertyChanged.Raise(this, "Machines");
		}

		void Download()
		{
			IsDownloadButtonEnabled = false;

			System.IO.Directory.CreateDirectory(mdbRoot);
			
			WebClientEx.Download(new Uri("http://jeskola.net/buzz/mdb/mdb.json.zip"), jsonPath, p => ProgressBarValue = p, () =>
			{
				DebugConsole.WriteLine("[MDB] Downloaded '{0}'", jsonPath);

				WebClientEx.Download(new Uri("http://jeskola.net/buzz/mdb/mdb_machines.zip"), machinesPath, p => ProgressBarValue = p, () =>
				{
					DebugConsole.WriteLine("[MDB] Downloaded '{0}'", machinesPath);
					unzip = true;
					PropertyChanged.Raise(this, "Machines");
				});
			});

		}

		void LoadDatabase()
		{
			loadDatabaseTask = Task.Factory.StartNew(() =>
			{
				var sw = new Stopwatch();
				sw.Start();
				try
				{
					database = MDB.Database.Load(jsonPath);
				}
				catch (Exception e)
				{
					DebugConsole.WriteLine("[MDB] Database load failed ({0})", e.Message);
					failed = true;
					return;
				}

				sw.Stop();
				DebugConsole.WriteLine("[MDB] Database load {0}ms", sw.ElapsedMilliseconds);

				if (unzip)
				{
					UnzipMachines();
					unzip = false;
				}
			}
			).ContinueWith(_ =>
			{
				AddDLLs();
				PropertyChanged.Raise(this, "Machines");
				IsListBoxEnabled = true;
				loadDatabaseTask = null;
			}, TaskScheduler.FromCurrentSynchronizationContext());

		}

		void UnzipMachines()
		{
			var sw = new Stopwatch();
			sw.Start();
			ZipFileEx.UnzipToPath(machinesPath, gearPath);
			sw.Stop();

			DebugConsole.WriteLine("[MDB] Unzip machines {0}ms", sw.ElapsedMilliseconds);
		}



		public void Release()
		{
			view.PropertyChanged -= view_PropertyChanged;
		}

		void view_PropertyChanged(object sender, PropertyChangedEventArgs e)
		{

		}


		#region INotifyPropertyChanged Members

		public event PropertyChangedEventHandler PropertyChanged;

		#endregion
	}
}