#include "opencv2/objdetect.hpp"
#include "opencv2/videoio.hpp"
#include "opencv2/highgui.hpp"
#include "opencv2/imgproc.hpp"

#include <iostream>
#include <stdio.h>

using namespace std;
using namespace cv;

/** Function Headers */
void detectAndDisplay(Mat frame);

/** Global variables */
String face_cascade_name = "data/haarcascade_frontalface_alt.xml";
String eyes_cascade_name = "data/haarcascade_eye_tree_eyeglasses.xml";
CascadeClassifier face_cascade;
CascadeClassifier eyes_cascade;
String window_name = "Capture - Face detection";
String window_frame_gray = "Frame gray";
String window_face_roi = "Face ROI";

/** @function main */
int main(void)
{
    VideoCapture capture(0);
    Mat frame;

    //-- 1. Load the cascades
    if (!face_cascade.load(face_cascade_name)) { printf("--(!)Error loading face cascade\n"); return -1; };
    if (!eyes_cascade.load(eyes_cascade_name)) { printf("--(!)Error loading eyes cascade\n"); return -1; };

    //-- 2. Read the video stream
    if (!capture.isOpened()) { printf("--(!)Error opening video capture\n"); return -1; }

    while (capture.read(frame))
    {
        if (frame.empty())
        {
            printf(" --(!) No captured frame -- Break!");
            break;
        }

        //-- 3. Apply the classifier to the frame
        detectAndDisplay(frame);

        int c = waitKey(10);
        if ((char)c == 27) { break; } // escape
    }
    return 0;
}

/** @function detectAndDisplay */
void detectAndDisplay(Mat frame)
{
    std::vector<Rect> faces;
    Mat frame_gray;

    cvtColor(frame, frame_gray, COLOR_BGR2GRAY);
    //imshow(window_name, frame);
    equalizeHist(frame_gray, frame_gray);
    //imshow(window_frame_gray, frame_gray);

    //-- Detect faces
    face_cascade.detectMultiScale(frame_gray, faces, 1.1, 2, 0 | CASCADE_SCALE_IMAGE, Size(30, 30));

    for (size_t i = 0; i < faces.size(); i++)
    {
        Point center(faces[i].x + faces[i].width / 2, faces[i].y + faces[i].height / 2);
        ellipse(frame, center, Size(faces[i].width / 2, faces[i].height / 2), 0, 0, 360, Scalar(255, 0, 255), 4, 8, 0);

        Mat faceROI = frame_gray(faces[i]);
        //imshow(window_face_roi, faceROI);
        std::vector<Rect> eyes;

        //-- In each face, detect eyes
        try {
            eyes_cascade.detectMultiScale(faceROI, eyes, 1.1, 2, 0 | CASCADE_SCALE_IMAGE, Size(30, 30));
        }
        catch (const std::exception& ex) {
            cout << "--(!)Error: " << ex.what();
        }


        for (size_t j = 0; j < eyes.size(); j++)
        {
            Point eye_center(faces[i].x + eyes[j].x + eyes[j].width / 2, faces[i].y + eyes[j].y + eyes[j].height / 2);
            int radius = cvRound((eyes[j].width + eyes[j].height)*0.25);
            circle(frame, eye_center, radius, Scalar(255, 0, 0), 4, 8, 0);
        }
    }
    //-- Show what you got
    imshow(window_name, frame);
}