using System;
using System.ComponentModel;
using System.Windows;
using System.Windows.Markup;
using System.Windows.Media;
using System.Windows.Media.Animation;

namespace Vec3.Wpf
{
	public abstract class ImageSourceAnimationBase : AnimationTimeline
	{
		public sealed override Type TargetPropertyType
		{
			get { return typeof( ImageSource ); }
		}

		protected ImageSourceAnimationBase()
		{
		}

		public new ImageSourceAnimationBase Clone()
		{
			return (ImageSourceAnimationBase)base.Clone();
		}

		public sealed override object GetCurrentValue( object defaultOriginValue,
			object defaultDestinationValue, AnimationClock animationClock )
		{
			if( animationClock == null )
				throw new ArgumentNullException( "animationClock" );

			if( animationClock.CurrentState == ClockState.Stopped )
				return defaultDestinationValue;

			return GetCurrentValueCore( (ImageSource)defaultOriginValue,
				(ImageSource)defaultDestinationValue, animationClock );
		}

		public ImageSource GetCurrentValue( ImageSource defaultOriginValue,
			ImageSource defaultDestinationValue, AnimationClock animationClock )
		{
			if( animationClock == null )
				throw new ArgumentNullException( "animationClock" );

			if( animationClock.CurrentState == ClockState.Stopped )
				return defaultDestinationValue;

			return GetCurrentValueCore( (ImageSource)defaultOriginValue,
				(ImageSource)defaultDestinationValue, animationClock );
		}

		protected abstract ImageSource GetCurrentValueCore( ImageSource defaultOriginValue,
			ImageSource defaultDestinationValue, AnimationClock animationClock );
	}

	[ContentProperty( "Frames" )]
	public class FlipBookAnimation : ImageSourceAnimationBase, IAddChild
	{
		#region Frames

		private FreezableCollection<ImageSource> frames;
		public FreezableCollection<ImageSource> Frames
		{
			get
			{
				ReadPreamble();

				if( frames == null )
				{
					if( IsFrozen )
					{
						frames = emptyFrames;
					}
					else
					{
						WritePreamble();

						frames = new FreezableCollection<ImageSource>();
						OnFreezablePropertyChanged( null, frames );

						WritePostscript();
					}
				}

				return frames;
			}

			set
			{
				if( value == null )
					throw new ArgumentNullException();

				WritePreamble();

				if( frames == value )
					return;

				OnFreezablePropertyChanged( frames, value );
				frames = value;

				WritePostscript();
			}
		}

		private static readonly FreezableCollection<ImageSource> emptyFrames;
		static FlipBookAnimation()
		{
			emptyFrames = new FreezableCollection<ImageSource>( 0 );
			emptyFrames.Freeze();
		}

		[EditorBrowsable( EditorBrowsableState.Never )]
		public bool ShouldSerializeFrames()
		{
			ReadPreamble();
			return frames != null && frames.Count > 0;
		}

		protected virtual void AddChild( ImageSource value )
		{
			Frames.Add( value );
		}

		void IAddChild.AddChild( object value )
		{
			var val = value as ImageSource;
			
			if( val == null )
				throw new ArgumentException();

			AddChild( val );
		}

		void IAddChild.AddText( string text )
		{
			throw new InvalidOperationException();
		}

		#endregion

		#region FrameTime

		public static readonly DependencyProperty FrameTimeProperty = DependencyProperty.Register(
			"FrameTime", typeof( TimeSpan ), typeof( FlipBookAnimation ),
			new UIPropertyMetadata( (TimeSpan)TimeSpan.FromSeconds( 1.0F / 30.0F ) ),
			ValidateFrameTime );

		public TimeSpan FrameTime
		{
			get { return (TimeSpan)GetValue( FrameTimeProperty ); }
			set { SetValue( FrameTimeProperty, value ); }
		}

		private static bool ValidateFrameTime( object value )
		{
			var t = (TimeSpan)value;
			return t > TimeSpan.Zero;
		}

		#endregion

		#region Freezable

		public new FlipBookAnimation Clone()
		{
			return (FlipBookAnimation)base.Clone();
		}

		protected override Freezable CreateInstanceCore()
		{
			return new FlipBookAnimation();
		}

		protected override bool FreezeCore( bool isChecking )
		{
			if( !base.FreezeCore( isChecking ) )
				return false;

			if( frames != null && !Freezable.Freeze( frames, isChecking ) )
				return false;

			return true;
		}

		protected override void CloneCore( Freezable sourceFreezable )
		{
			base.CloneCore( sourceFreezable );

			var source = (FlipBookAnimation)sourceFreezable;

			if( source.frames != null )
			{
				frames = (FreezableCollection<ImageSource>)source.frames.Clone();
				OnFreezablePropertyChanged( null, frames );
			}
		}

		protected override void CloneCurrentValueCore( Freezable sourceFreezable )
		{
			base.CloneCurrentValueCore( sourceFreezable );

			var source = (FlipBookAnimation)sourceFreezable;

			if( source.frames != null )
			{
				frames = (FreezableCollection<ImageSource>)source.frames.CloneCurrentValue();
				OnFreezablePropertyChanged( null, frames );
			}
		}

		protected override void GetAsFrozenCore( Freezable sourceFreezable )
		{
			base.GetAsFrozenCore( sourceFreezable );

			var source = (FlipBookAnimation)sourceFreezable;

			if( source.frames != null )
			{
				frames = (FreezableCollection<ImageSource>)source.frames.GetAsFrozen();
				OnFreezablePropertyChanged( null, frames );
			}
		}

		protected override void GetCurrentValueAsFrozenCore( Freezable sourceFreezable )
		{
			base.GetCurrentValueAsFrozenCore( sourceFreezable );

			var source = (FlipBookAnimation)sourceFreezable;

			if( source.frames != null )
			{
				frames = (FreezableCollection<ImageSource>)source.frames.GetCurrentValueAsFrozen();
				OnFreezablePropertyChanged( null, frames );
			}
		}

		#endregion

		protected override ImageSource GetCurrentValueCore( ImageSource defaultOriginValue,
			ImageSource defaultDestinationValue, AnimationClock animationClock )
		{
			if( frames == null || frames.Count == 0 )
				return defaultDestinationValue;

			var now = animationClock.CurrentTime.Value;
			
			long frame = now.Ticks / FrameTime.Ticks;

			if( frame <= 0 )
				return frames[0];

			return frames[(int)(frame % frames.Count)];
		}

		protected override Duration GetNaturalDurationCore( Clock clock )
		{
			int numFrames = frames != null ? frames.Count : 0;
			return new Duration( new TimeSpan( FrameTime.Ticks * numFrames ) );
		}
	}

}