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

using OpenCvSharp;
using System.Drawing;

namespace MathPirate.AlternativeInputDevices.FacialRecognition
{
    public static class DetectFaces
    {
        private static CvHaarClassifierCascade _classifierCascade;
        private static CvMemStorage _memStorage;

        //YAY!  Hardcoded paths are awesome!
        private static string _classifierFile = @"E:\svn\Projects\AlternativeInputDevices\FacialRecognition\Data\haarcascade_frontalface_alt2.xml";

        static DetectFaces()
        {
            //Workaround for crashing bug while loading classifier.
            IplImage fakeImage = new IplImage(100, 100, BitDepth.U8, 1);
            fakeImage.Erode(fakeImage);
            fakeImage.Dispose();

            _classifierCascade = CvHaarClassifierCascade.FromFile(_classifierFile);
            _memStorage = new CvMemStorage(0);
        }

        public static Rectangle[] Detect(IplImage image)
        {
            CvSeq sequence = _classifierCascade.HaarDetectObjects(image, _memStorage, 1.2, 30, HaarDetectionType.DoCannyPruning, new CvSize(40, 40));

            List<Rectangle> faces = new List<Rectangle>();

            for (int i = 0; i < sequence.Total; i++)
            {
                CvRect? rect = sequence.GetSeqElem<CvRect>(i);
                if(!rect.HasValue)
                {
                    continue;
                }
                CvRect rectValue = rect.Value;

                Rectangle rectangle = new Rectangle(rectValue.X, rectValue.Y, rectValue.Width, rectValue.Height);
                faces.Add(rectangle);
            }

            return faces.ToArray();
        }

        public static Rectangle[] Detect(Bitmap bmp)
        {
            IplImage image = IplImage.FromBitmap(bmp);
            Rectangle[] faces = Detect(image);
            image.Dispose();
            return faces;
        }

        public static Bitmap[] ExtractFaces(Rectangle[] faces, Bitmap bmp)
        {
            List<Bitmap> faceBitmaps = new List<Bitmap>();
            foreach (Rectangle faceRect in faces)
            {
                Bitmap newFace = new Bitmap(faceRect.Width, faceRect.Height);

                Graphics newFaceGraphics = Graphics.FromImage(newFace);
                newFaceGraphics.DrawImage(bmp, new Rectangle(Point.Empty, faceRect.Size), faceRect, GraphicsUnit.Pixel);
                newFaceGraphics.Dispose();

                faceBitmaps.Add(newFace);
            }
            return faceBitmaps.ToArray();
        }
    }
}