using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using OpenCvSharp;

namespace AtariRobot.Pong
{
    public class Recognizer
    {
        public PongScreen Recognize(IplImage image)
        {
            IplImage smoothFrame = new IplImage(image.Width, image.Height, image.Depth, image.ElemChannels);
            Cv.Smooth(image, smoothFrame, SmoothType.Gaussian);
            Cv.Smooth(smoothFrame, smoothFrame, SmoothType.Gaussian);

            IplImage greyFrame = new IplImage(smoothFrame.Width, smoothFrame.Height, BitDepth.U8, 1);
            Cv.CvtColor(smoothFrame, greyFrame, ColorConversion.RgbToGray);
            smoothFrame.Dispose();

            IplImage cannyFrame = new IplImage(image.Width, image.Height, BitDepth.U8, 1);
            Cv.Canny(greyFrame, cannyFrame, 100, 100);
            greyFrame.Dispose();

            Cv.ShowImage("EdgeDetect", cannyFrame);

            CvMemStorage memStorage = new CvMemStorage();

            CvSeq<CvPoint> contourSet;
            Cv.FindContours(cannyFrame, memStorage, out contourSet, CvContour.SizeOf, ContourRetrieval.External);
            cannyFrame.Dispose();

            List<ColorBox> colorBoxes = new List<ColorBox>();

            if (contourSet != null)
            {
                IplImage contourFrame = new IplImage(image.Width, image.Height, image.Depth, image.ElemChannels);
                contourFrame.Zero();
                for (CvSeq<CvPoint> currentContour = contourSet; currentContour != null; currentContour = currentContour.HNext)
                {
                    CvRect bounding = currentContour.BoundingRect();
                    if (bounding.Width < 3 || bounding.Height < 3) { continue; }
                    CvColor color = Helper.GetColorFromBounding(image, bounding);
                    color = Helper.FindClosestKnownColor(color);

                    Cv.DrawContours(contourFrame, currentContour, color, color, 0);

                    ColorBox newBox = new ColorBox() { Box = bounding, Color = color };
                    if (!colorBoxes.Contains(newBox))
                    {
                        colorBoxes.Add(newBox);
                    }
                }
                contourSet.Dispose();
            
                Cv.ShowImage("Contours", contourFrame);
                contourFrame.Dispose();
            }

            memStorage.Dispose();

            PongScreen screen = new PongScreen();

            List<ColorBox> discardedBoxes = new List<ColorBox>();
            //Find borders.
            //Borders are big white-like things that take up >70% of the screen width.
            foreach (ColorBox colorBox in colorBoxes)
            {
                CvRect box = colorBox.Box;

                if (box.Width > .7 * image.Width)
                {
                    if (box.Y > (image.Height / 2))
                    {
                        screen.BottomBorder = colorBox;
                    }
                    else
                    {
                        screen.TopBorder = colorBox;
                    }

                    discardedBoxes.Add(colorBox);
                }
            }

            if (screen.TopBorder != null && screen.BottomBorder != null)
            {
                //Throw out the boundaries and everything outside of them.
                colorBoxes.RemoveAll(x => discardedBoxes.Contains(x));
                colorBoxes.RemoveAll(x => x.Box.Y <= screen.TopBorder.Box.Y || x.Box.Y >= screen.BottomBorder.Box.Y);
                colorBoxes.RemoveAll(x => x.Color.Equals(CvColor.Black));

                colorBoxes.Sort((a, b) => Comparer<int>.Default.Compare(b.Box.Height * b.Box.Width, a.Box.Height * a.Box.Width));

                if (colorBoxes.Count < 3)
                {
                    //I don't have enough stuff, so I don't know what's going on.
                    return screen;
                }

                //Find paddles.
                //Most of the time, they're the two biggest things in the playfield.
                ColorBox paddleCandidateA = colorBoxes[0];
                ColorBox paddleCandidateB = colorBoxes[1];

                if (paddleCandidateA.Box.X < paddleCandidateB.Box.X)
                {
                    screen.LeftPaddle = paddleCandidateA;
                    screen.RightPaddle = paddleCandidateB;
                }
                else
                {
                    screen.LeftPaddle = paddleCandidateB;
                    screen.RightPaddle = paddleCandidateA;
                }

                //Find ball.
                //Most of the time, it's the third biggest thing in the playfield.
                screen.Ball = colorBoxes[2];
            }
            return screen;
        }
    }
}