using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using bbiwarg.Recognition.Tracking;
using bbiwarg.Utility;

namespace bbiwarg.Recognition.TouchRecognition
{
    public delegate void TouchEventHandler(object sender, TouchEventArgs e);
    public class TouchEventArgs : EventArgs
    {
        public int TrackID { get; private set; }
        public Vector2D AbsolutePosition { get; private set; }
        public Vector2D RelativePosition { get; private set; }

        public TouchEventArgs(int trackID, Vector2D absolutePosition, Vector2D relativePosition)
        {
            TrackID = trackID;
            AbsolutePosition = absolutePosition;
            RelativePosition = relativePosition;
        }
    }

    class TrackedTouchEvent : TrackedObject<TouchEvent>
    {
        private Kalman2DPositionFilter absolutePositionKalman;
        private Kalman2DPositionFilter relativePositionKalman;
        private int fingerID;
        private bool isTouchActive;

        public Vector2D AbsolutePositionPrediction { get { return absolutePositionKalman.getPrediction(); } }
        public Vector2D RelativePositionPrediction { get { return relativePositionKalman.getPrediction(); } }

        public event TouchEventHandler TouchDown;
        public event TouchEventHandler TouchMove;
        public event TouchEventHandler TouchUp;

        public TrackedTouchEvent(int id, TouchEvent detectedTouchEvent, int numFramesDetectedUntilTracked, int numFramesLostUntilDeleted)
            : base(id, detectedTouchEvent, numFramesDetectedUntilTracked, numFramesLostUntilDeleted)
        {
            absolutePositionKalman = new Kalman2DPositionFilter(Constants.TouchmXX, Constants.TouchmXY, Constants.TouchmYY);
            absolutePositionKalman.setInitialPosition(detectedTouchEvent.AbsolutePosition);

            relativePositionKalman = new Kalman2DPositionFilter(Constants.TouchmXX, Constants.TouchmXY, Constants.TouchmYY);
            relativePositionKalman.setInitialPosition(detectedTouchEvent.RelativePosition);

            fingerID = detectedTouchEvent.Finger.TrackID;
            isTouchActive = false;

            logStateChange();
        }

        public override void updateFrame(TouchEvent detectedTouchEvent)
        {
            base.updateFrame(detectedTouchEvent);

            if (NumFramesInCurrentState == 1)
                logStateChange();

            if (detectedTouchEvent != null)
            {
                Vector2D correctedAbsolutePosition = absolutePositionKalman.getCorrectedPosition(detectedTouchEvent.AbsolutePosition);
                Vector2D correctedRelativePosition = relativePositionKalman.getCorrectedPosition(detectedTouchEvent.RelativePosition);

                if (CurrentState == TrackingState.Tracked)
                {
                    if (!isTouchActive)
                        TriggerTouchDown(new TouchEventArgs(ID, correctedAbsolutePosition, correctedRelativePosition));
                    else
                        TriggerTouchMove(new TouchEventArgs(ID, correctedAbsolutePosition, correctedRelativePosition));
                }
            }
            else if (isTouchActive && CurrentState == TrackingState.Deleted)
                TriggerTouchUp(new TouchEventArgs(ID, AbsolutePositionPrediction, RelativePositionPrediction));

        }

        public override float calculateSimilarity(TouchEvent detectedTouchEvent)
        {
            //finger similarity
            float fingerSimilarity = (fingerID == detectedTouchEvent.Finger.TrackID) ? 1 : 0;

            //absolute position similarity
            float absoluteDistance = detectedTouchEvent.AbsolutePosition.getDistanceTo(AbsolutePositionPrediction);
            float absoluteSimilarity = Math.Max(0, 1 - absoluteDistance / Constants.ImageDiagonalLength);
            
            //relative position similarity
            float relativeDistance = detectedTouchEvent.RelativePosition.getDistanceTo(RelativePositionPrediction);
            float relativeSimilarity = Math.Max(0, 1 - relativeDistance / 1f);

            float similarity = fingerSimilarity * absoluteSimilarity * relativeSimilarity;

            return similarity;
        }

        private void logStateChange()
        {
            String stateAsString = CurrentState.ToString().ToLower();
            Logger.log(String.Format("TouchEvent #{0} {1}", this.ID, stateAsString), LogSubject.TouchTracker);
        }

        private void TriggerTouchDown(TouchEventArgs e)
        {
            if (TouchDown != null)
            {
                isTouchActive = true;
                TouchDown(this, e);
                Logger.log(String.Format("TouchEvent #{0} TouchDown at {1}", this.ID, e.RelativePosition), LogSubject.TouchEvents);
            }
        }

        private void TriggerTouchMove(TouchEventArgs e)
        {
            if (TouchMove != null)
            {
                TouchMove(this, e);
                Logger.log(String.Format("TouchEvent #{0} TouchMove at {1}", this.ID, e.RelativePosition), LogSubject.TouchEvents);
            }
        }

        private void TriggerTouchUp(TouchEventArgs e)
        {
            if (TouchUp != null)
            {
                isTouchActive = false;
                TouchUp(this, e);
                Logger.log(String.Format("TouchEvent #{0} TouchUp at {1}", this.ID, e.RelativePosition), LogSubject.TouchEvents);
            }
        }

    }
}