using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using bbiwarg.Recognition.HandRecognition;
using bbiwarg.Utility;
using Emgu.CV.Structure;
using Emgu.CV;

namespace bbiwarg.Recognition.PalmRecognition
{
    class PalmDetector
    {
        private List<Hand> hands;
        private List<Hand> palmHands;

        public List<Palm> Palms { get; private set; }

        public PalmDetector(List<Hand> hands)
        {
            this.hands = hands;

            findPalmHands();
            createPalms();
        }

        private void findPalmHands()
        {
            palmHands = new List<Hand>();

            foreach (Hand hand in hands)
            {
                if (hand.ThumbDefect != null)
                    palmHands.Add(hand);
            }
        }

        private void createPalms()
        {
            Palms = new List<Palm>();
            foreach (Hand palmHand in palmHands)
            {
                ConvexityDefect thumbDefect = palmHand.ThumbDefect;
                Vector2D directionWristFinger = thumbDefect.VectorLong.normalize();
                Vector2D directionFingerWrist = directionWristFinger.getInverse();
                Vector2D directionUpperLower = directionWristFinger.getOrthogonal(palmHand.Side == HandSide.Right);
                Vector2D directionLowerUpper = directionUpperLower.getInverse();

                //handLength
                Vector2D handLength = 1.5f * thumbDefect.VectorLong;

                //fingersUpper
                Vector2D fingersUpper = thumbDefect.OuterLong;
                bool handBelow = true;
                while (handBelow && fingersUpper.isInBound())
                {
                    fingersUpper += directionWristFinger;
                    Vector2D below = fingersUpper.copy();
                    bool handBelowFound = false;
                    while (!handBelowFound && below.getDistanceTo(fingersUpper) < 2 * Parameters.FingerMaxWidth && below.isInBound())
                    {
                        below += directionUpperLower;
                        handBelowFound = palmHand.isInside(below);
                    }
                    handBelow = handBelowFound;
                }

                //wristUpper
                Vector2D wristUpper = thumbDefect.Inner + 5 * directionFingerWrist;
                while (wristUpper.isInBound() && palmHand.isInside(wristUpper))
                    wristUpper += directionFingerWrist;

                //handWidth
                Vector2D handWidth = getHandWidth(palmHand, directionUpperLower);

                //wristLower
                Vector2D wristLower = wristUpper + handWidth;

                //fingersLower
                Vector2D fingersLower = wristLower + 0.75f * handLength - 0.25f * handWidth;


                Palm palm = new Palm(palmHand, wristUpper, wristLower, fingersLower, fingersUpper);
                Palms.Add(palm);
                palmHand.setPalm(palm);

            }
        }

        private Vector2D getHandWidth(Hand palmHand, Vector2D directionUpperLower)
        {
            Vector2D lineStart = palmHand.ThumbDefect.Inner;
            Vector2D lineEnd = palmHand.ThumbDefect.OuterLong;
            Vector2D step = (lineEnd - lineStart) / Parameters.PalmNumPositionsForHandWidth;
            Vector2D currentStart = lineStart;

            Vector2D maxWidth = null;
            float maxWidthLength = float.MinValue;

            for (int i = 0; i < Parameters.PalmNumPositionsForHandWidth; i++)
            {
                Vector2D lower = currentStart + 10 * directionUpperLower;
                while (lower.isInBound() && palmHand.isInside(lower))
                    lower += directionUpperLower;
                Vector2D width = (lower - currentStart);
                float length = width.Length;
                if (length > maxWidthLength)
                {
                    maxWidth = width;
                    maxWidthLength = length;
                }
                currentStart += step;
            }
            return maxWidth;
        }
    }
}