using UnityEngine;
using System.Collections.Generic;

namespace Flux
{
	public class FAnimationTrack : FTransformTrack {
		// Animation Previews, stored in <sequenceInstanceId, <ownerInstanceId, animPreview>>
		private static Dictionary<int, Dictionary<int, FAnimationTrackCache>> _animPreviews = new Dictionary<int, Dictionary<int, FAnimationTrackCache>>();

		public static FAnimationTrackCache GetAnimationPreview( FSequence sequence, Transform owner )
		{
			Dictionary<int, FAnimationTrackCache> sequencePreviews = null;

			FAnimationTrackCache animationTrackCache = null;

			if( _animPreviews.TryGetValue( sequence.GetInstanceID(), out sequencePreviews ) )
			{
				sequencePreviews.TryGetValue(owner.GetInstanceID(), out animationTrackCache );
			}

			return animationTrackCache;
		}

		private static FAnimationTrackCache GetAnimationPreview( FAnimationTrack animTrack )
		{
			return GetAnimationPreview( animTrack, true );
		}

		private static FAnimationTrackCache GetAnimationPreview( FAnimationTrack animTrack, bool createIfDoesntExist )
		{
			Dictionary<int, FAnimationTrackCache> sequencePreviews = null;
			if( !_animPreviews.TryGetValue( animTrack.Sequence.GetInstanceID(), out sequencePreviews ) )
			{
				if( !createIfDoesntExist )
					return null;
				sequencePreviews = new Dictionary<int, FAnimationTrackCache>();
				_animPreviews.Add( animTrack.Sequence.GetInstanceID(), sequencePreviews );
			}

			FAnimationTrackCache preview = null;
			if( !sequencePreviews.TryGetValue( animTrack.Owner.GetInstanceID(), out preview ) )
			{
				if( !createIfDoesntExist )
					return null;
				preview = new FAnimationTrackCache( animTrack );
				sequencePreviews.Add( animTrack.Owner.GetInstanceID(), preview );
			}

			return preview;
		}

		private static void DeleteAnimationPreview( FAnimationTrack animTrack )
		{
			Dictionary<int, FAnimationTrackCache> sequencePreviews = null;
			if( _animPreviews.TryGetValue( animTrack.Sequence.GetInstanceID(), out sequencePreviews ) )
			{
				sequencePreviews[animTrack.Owner.GetInstanceID()].Clear();
				sequencePreviews.Remove(animTrack.Owner.GetInstanceID());
			}
		}

		public static void DeleteAnimationPreviews( FSequence sequence )
		{
			Dictionary<int, FAnimationTrackCache> sequencePreviews = null;
			if( _animPreviews.TryGetValue( sequence.GetInstanceID(), out sequencePreviews ) )
			{
				Dictionary<int, FAnimationTrackCache>.Enumerator e = sequencePreviews.GetEnumerator();
				while( e.MoveNext() )
				{
					e.Current.Value.Clear();
				}
				sequencePreviews.Clear();

				_animPreviews.Remove( sequence.GetInstanceID() );
			}
		}

		// what is the animation controller that will be used to 
		// build this track's animation state machine
		[SerializeField]
		[HideInInspector]
		private RuntimeAnimatorController _animatorController = null;
		public RuntimeAnimatorController AnimatorController { get { return _animatorController; } }

		[SerializeField]
		[HideInInspector]
		private string _layerName = null;
		public string LayerName { get { return _layerName; } }

		[SerializeField]
		[HideInInspector]
		private int _layerId = -1;
		public int LayerId { get { return _layerId; } }

//		private TransformSnapshot _snapshot = null;
//		public TransformSnapshot Snapshot { get { return _snapshot; } }

		public override CacheMode RequiredCacheMode {
			get {
				return CacheMode.Editor | CacheMode.RuntimeBackwards;
			}
		}

		public override CacheMode AllowedCacheMode {
			get {
				return RequiredCacheMode | CacheMode.RuntimeForward;
			}
		}

		public override void Init()
		{
			if( Owner.GetComponent<Animator>() == null )
				Owner.gameObject.AddComponent<Animator>();

			base.Init();

			_snapshot.TakeChildSnapshots();
		}

		public override void Stop ()
		{
			if( HasCache && Cache.Track == this )
			{
				((FAnimationTrackCache)Cache).StopPlayback();
				Owner.GetComponent<Animator>().enabled = false;
			}

			base.Stop();
		}

		public override void UpdateEventsEditor( int frame, float time )
		{
			if( HasCache && Cache.Track == this )
			{
				GetPreviewAt( time );
			}
		}

		public override void UpdateEvents( int frame, float time )
		{
			if( Sequence.Speed != 1 && !HasCache )
				Owner.GetComponent<Animator>().speed = Sequence.Speed;
			if( HasCache )
			{
				if( Cache.Track == this ) // only one of them needs to set the playback
					GetPreviewAt( time );
			}
			else
				base.UpdateEvents(frame, time);
		}
			
		public override void CreateCache()
		{
			FAnimationTrackCache preview = GetAnimationPreview( this );
			preview.Build(true);
		}

		public override void ClearCache()
		{
			FAnimationTrackCache preview = (FAnimationTrackCache)Cache;//GetAnimationPreview( this, false );
			if( preview != null )
			{
				if( preview.NumberTracksCached <= 1 )
					DeleteAnimationPreview( this );
				else
					preview.Build(true);
			}
			Cache = null;
		}

		public override bool CanCreateCache()
		{
			if( _animatorController == null )
				return false;
			
			List<FEvent> evts = Events;
			for( int i = 0; i != evts.Count; ++i )
			{
				if( ((FPlayAnimationEvent)evts[i])._animationClip == null )
					return false;
			}
			
			return true;
		}

		private void GetPreviewAt( float time )
		{
			Cache.GetPlaybackAt( time );
		}

		private bool HasAnimationOnFrame( int frame )
		{
			FEvent[] evts = new FEvent[2];
			int numEvents = GetEventsAt( frame, evts );
			if( numEvents == 0 )
				return false;
			
			return ((FPlayAnimationEvent)evts[0])._animationClip != null || (numEvents == 2 && ((FPlayAnimationEvent)evts[1])._animationClip != null );
		}
	}
}