/* 

   Copyright (C) Arnaud Houdelette		2012-2014
   Copyright (C) Emmanuel Langlois		2012-2014

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

using System;
using System.Runtime.InteropServices;
using System.Collections.Generic;
using System.Linq;

namespace DMX2
{
	public partial class MidiEventProvider : IEventProvider 
	{

		/// <summary>
		/// Classe pour contenir et gérer un unique Handle d'acces au sequenceur midi Alsa.
		/// </summary>
		public class MidiSeqHandle : IDisposable
		{
			static MidiSeqHandle singleton = new MidiSeqHandle();
			IntPtr midi_seq_handle = IntPtr.Zero;

			public static IntPtr Handle {
				get {
					return singleton.midi_seq_handle;
				}
			}

			MidiSeqHandle(){
				snd_seq_open(out midi_seq_handle, "default",SND_SEQ_OPEN_DUPLEX,0);
				snd_seq_set_client_name(midi_seq_handle,"DMX2");
				snd_seq_create_simple_port(midi_seq_handle,"dmx_ctrl",
			                                      SND_SEQ_PORT_CAP_WRITE + SND_SEQ_PORT_CAP_SUBS_WRITE, 
			                                      SND_SEQ_PORT_TYPE_APPLICATION);
			}

			#region IDisposable implementation
			void IDisposable.Dispose ()
			{
				if(midi_seq_handle != IntPtr.Zero) 
					snd_seq_close(midi_seq_handle);
				midi_seq_handle = IntPtr.Zero;
			}
			#endregion
			~MidiSeqHandle(){
				((IDisposable)this).Dispose ();
			}

		}

		class internalEvent {
			public string internalName;
			public string description;
			public internalEvent(string _id, string _desc)
			{
				internalName=_id;
				description=_desc;
			}
		}

		class midiFeedbackInfo : IFeedbackInfo {
			#region IFeedbackInfo implementation
			bool IFeedbackInfo.FeedBack (byte data)
			{
				throw new System.NotImplementedException ();
			}
			#endregion
		}

		Dictionary<string,internalEvent> eventlist = new Dictionary<string, internalEvent>();

		EventData last; 
		internalEvent levent=null;
		bool connected=false;

		public MidiEventProvider (EventManager manager)
		{
			manager.RegisterProvider(this);
		}

		#region IEventProvider implementation

		bool IEventProvider.Bind (string eventId)
		{
			// On indique a l'EventManager qu'on traite, si l'ID commence par 'MIDI-'
			return eventId.StartsWith("MIDI-");
		}

		void IEventProvider.Unbind (string eventId)
		{
			return;
		}

		Gtk.Menu IEventProvider.GetProviderSubMenu (EventManager.EventMenuData state, Gtk.ButtonPressEventHandler handler)
		{
			if(!connected) return null;											// Si pas encore recu d'evenements => pas de menu
			Gtk.Menu retmenu = new Gtk.Menu ();

			if (levent != null) {												// Creation du sous menu "Dernier"
				Gtk.MenuItem lmenuitem = new Gtk.MenuItem ("Dernier");
				retmenu.Add (lmenuitem);
				Gtk.Menu lmenu = new Gtk.Menu ();
				lmenuitem.Submenu = lmenu;
				Gtk.MenuItem item = new Gtk.MenuItem(levent.description);
				item.Data[EventManager.EventIdKey] = levent.internalName;
				item.Data[EventManager.StateKey] = state;
				item.ButtonPressEvent += handler;
				lmenu.Add (item);
			}

			Gtk.MenuItem evmenuitem = new Gtk.MenuItem ("Events");				// Creation du sous menu "Events"
			retmenu.Add (evmenuitem);
			Gtk.Menu evmenu = new Gtk.Menu ();
			evmenuitem.Submenu = evmenu;

			List<string> sortedKeys = eventlist.Keys.ToList();		// On recupere des IDs 
			sortedKeys.Sort();										// et on les trie

			foreach ( string key in sortedKeys ) {
				internalEvent evt= eventlist[key];
				Gtk.MenuItem item = new Gtk.MenuItem(evt.description);
				item.Data[EventManager.EventIdKey] = evt.internalName;
				item.Data[EventManager.StateKey] = state;
				item.ButtonPressEvent += handler;
				evmenu.Add (item);
			}

			return retmenu;

		}

		void IEventProvider.ProcessEvents (EventManagerCallback callback)
		{
			IntPtr evPtr; // Pointeur vers la structure non managée alsa-seq

			// Tant qu'il y des evenements midi en attente
			while ((snd_seq_event_input_pending(MidiSeqHandle.Handle,1))>0) {
				snd_seq_event_input(MidiSeqHandle.Handle, out evPtr);	// Recup du pointeur vers l'ev
				snd_seq_event_t evS =(snd_seq_event_t) Marshal.PtrToStructure(evPtr,typeof(snd_seq_event_t)); // Copie de la zone mémoire dans une structure managee
				snd_seq_free_event(evPtr); // liberation du pointeur

				string id=null, description=null; int value=0;

				switch (evS.type) {
				case snd_seq_event_type_t.SND_SEQ_EVENT_PORT_SUBSCRIBED:	// Connection d'un périph midi
					connected = true;
					continue;
				case snd_seq_event_type_t.SND_SEQ_EVENT_CONTROLLER:
					id= string.Format("MIDI-CTRL-C{0}P{1}",evS.data_ev_ctrl.channel,evS.data_ev_ctrl.param);
					description = string.Format("Controller Ch {0} Param {1}",evS.data_ev_ctrl.channel,evS.data_ev_ctrl.param);
					value = 255 * evS.data_ev_ctrl.value / 127;				// Conversion {0,127} => {0,255}
					break;
				case snd_seq_event_type_t.SND_SEQ_EVENT_NOTEON:
					id= string.Format("MIDI-NOTE-C{0}N{1}",evS.data_ev_note.channel, evS.data_ev_note.note );
					description = string.Format("Note {1} Ch {0}",evS.data_ev_note.channel, evS.data_ev_note.note );
					value = 255 ;
					break;
				case snd_seq_event_type_t.SND_SEQ_EVENT_NOTEOFF:
					id= string.Format("MIDI-NOTE-C{0}N{1}",evS.data_ev_note.channel, evS.data_ev_note.note );
					description = string.Format("Note {1} Ch {0}",evS.data_ev_note.channel, evS.data_ev_note.note );
					value = 0; 
					break;
				case snd_seq_event_type_t.SND_SEQ_EVENT_CLOCK:
				case snd_seq_event_type_t.SND_SEQ_EVENT_SENSING:
					continue;

				//TODO : Regarder si d'autres controles interessants.
				default:
						id= null;
#if DEBUG
						Info.Publish(string.Format ("event {0}", evS.type) );	// On affiche les evenements inconnus
#endif
					continue;
				}

				connected=true;

				if(id!=null)
				{
					if(!eventlist.ContainsKey(id))
						eventlist.Add(id,new internalEvent(id,description));
					levent= eventlist[id];					//Dernier Evenement recu conserve pour menu
					EventData evData = new EventData();		
					evData.id = id;
					evData.value = (byte)value;

					if(evData.Equals(last)) continue;		// On ignore les evenements répétés à l'identique
	
					callback(evData);
					last = evData;
				}
			}
		}

		string IEventProvider.MenuName {
			get {
				return "Midi";
			}
		}

		IFeedbackInfo IEventProvider.GetFeedbackInfo (string eventId)
		{
			return null;
		}

		#endregion

	}
}