using System.Collections.Generic;

namespace Aiwaz.Common.Animations
{
    struct AnimationInterval
	{
		public AnimationInterval(double argBegin, double argEnd)
		{
			begin = argBegin;
			end = argEnd;
		}

		public double begin;
        public double end;
	}

    class ForwardComparer : IComparer<AnimationInterval>
    {
        public int Compare(AnimationInterval a, AnimationInterval b)
        {
            return a.begin < b.begin ? -1 : (a.begin > b.begin ? 1 : 0);
        }
    }

    class BackwardComparer : IComparer<AnimationInterval>
    {
        public int Compare(AnimationInterval a, AnimationInterval b)
        {
            return a.end > b.end ? -1 : (a.end > b.end ? 1 : 0);
        }
    }

    public static class AnimationManager
    {
	    private static SortedList<AnimationInterval, List<Pair<Animation, uint>>> forwardSortedAnimations = new SortedList<AnimationInterval, List<Pair<Animation, uint>>>(new ForwardComparer());
        private static SortedList<AnimationInterval, List<Pair<Animation, uint>>> backwardSortedAnimations = new SortedList<AnimationInterval, List<Pair<Animation, uint>>>(new BackwardComparer());
        private static SortedList<AnimationInterval, List<Pair<Animation, uint>>> realTimeAnimations = new SortedList<AnimationInterval, List<Pair<Animation, uint>>>(new ForwardComparer());
        private static SortedList<double, List<Pair<Event, uint>>> demoTimeEvents = new SortedList<double, List<Pair<Event, uint>>>();
        private static SortedList<double, List<Pair<Event, uint>>> realTimeEvents = new SortedList<double, List<Pair<Event, uint>>>();

        private static double previousDemoTime;
        private static double previousRealTime;

        public static void AddDemoTimeAnimation(double argBeginTime, double argEndTime, Animation argAnimation, uint argUserData)
        {
            forwardSortedAnimations[new AnimationInterval(argBeginTime, argEndTime)].Add(new Pair<Animation, uint>(argAnimation, argUserData));
            backwardSortedAnimations[new AnimationInterval(argBeginTime, argEndTime)].Add(new Pair<Animation, uint>(argAnimation, argUserData));
        }

        public static void AddRealTimeAnimation(double argBeginTime, double argEndTime, Animation argAnimation, uint argUserData)
        {
            realTimeAnimations[new AnimationInterval(argBeginTime, argEndTime)].Add(new Pair<Animation, uint>(argAnimation, argUserData));
        }

        public static void AddDemoTimeEvent(double argTime, Event argEvent, uint argUserData)
        {
            demoTimeEvents[argTime].Add(new Pair<Event, uint>(argEvent, argUserData));
        }

        public static void AddRealTimeEvent(double argTime, Event argEvent, uint argUserData)
        {
            realTimeEvents[argTime].Add(new Pair<Event, uint>(argEvent, argUserData));
        }

        public static void Animate()
        {
	        double demoTime = Timeline.DemoTime;
	        double realTime = Timeline.RealTime;
        	
	        // Gather all active animations, they are the ones that started before now and end after now.
	        // Do this for both the demo time and real time.
	        List<Pair<Pair<Animation, uint>, double>> lk_ActiveAnimations = new List<Pair<Pair<Animation, uint>, double>>();

	        // Demo time animations: Demo time can go backwards, so search from both directions
	        if (Timeline.SpeedAndDirection > 0)
	        {
                foreach (var entry in forwardSortedAnimations)
                {
			        if (entry.Key.begin <= demoTime && entry.Key.end >= demoTime)
			        {
                        foreach (var animation in entry.Value)
				        {
					        lk_ActiveAnimations.Add(new Pair<Pair<Animation, uint>, double>(animation, (demoTime - entry.Key.begin) / (entry.Key.end - entry.Key.begin)));
				        }
			        }

			        if (entry.Key.begin > demoTime)
				        break;
		        }
	        }
            else if (Timeline.SpeedAndDirection < 0)
	        {
                foreach (var entry in backwardSortedAnimations)
		        {
			        if (entry.Key.end >= demoTime && entry.Key.begin <= demoTime)
			        {
				        foreach (var animation in entry.Value)
				        {
					        lk_ActiveAnimations.Add(new Pair<Pair<Animation, uint>, double>(animation, (demoTime - entry.Key.begin) / (entry.Key.end - entry.Key.begin)));
				        }
			        }

			        if (entry.Key.end < demoTime)
				        break;
		        }
	        }

	        // Real time animations: The time that we know doesn't allow us to travel to the past, so just check into the future:
	        foreach (var entry in realTimeAnimations)
	        {
			    if (entry.Key.begin <= demoTime && entry.Key.end >= demoTime)
		        {
				    foreach (var animation in entry.Value)
			        {
					    lk_ActiveAnimations.Add(new Pair<Pair<Animation, uint>, double>(animation, (demoTime - entry.Key.begin) / (entry.Key.end - entry.Key.begin)));
			        }
		        }

		        if (entry.Key.begin > demoTime)
			        break;
	        }

	        // Now that we know what animations correspond to this time, animate them!
            foreach (var anim in lk_ActiveAnimations)
            {
                anim.First.First.Animate(anim.Second, anim.First.Second);
	        }

	        // Fire all events that happened since last time:
            foreach (var entry in demoTimeEvents)
	        {
		        double time = entry.Key;

                foreach (var evt in entry.Value)
		        {
                    if ((Timeline.SpeedAndDirection > 0) && (time >= previousDemoTime && time <= demoTime))
                    {
                        evt.First.Do(evt.Second);
                    }
                    else if ((Timeline.SpeedAndDirection < 0) && (time <= previousDemoTime && time >= demoTime))
			        {
				        evt.First.Undo(evt.Second);
			        }
		        }
	        }

            foreach (var entry in realTimeEvents)
	        {
		        double time = entry.Key;

                foreach (var evt in entry.Value)
		        {
			        if (time >= previousDemoTime && time <= demoTime)
			        {
                        evt.First.Do(evt.Second);
			        }
		        }
	        }

	        previousDemoTime = demoTime;
	        previousRealTime = realTime;
        }
    }
}