//C++

#include <iostream>
//include those opencv2 files in our program
#include "opencv2/opencv.hpp"
#include "opencv2/videoio.hpp" 
#include "opencv2/highgui.hpp"

int FPS=30; //FPS variable. FPS is the framerate of your video, aka your recording device's
int DISCARD_DURATION=5;
bool isDiscardData=true;
int countDiscard=0;


int main(){ 
	//Print "PPG algorithm" to terminal
	//Note to self: std::endl; returns to line in terminal; use it everytime when done printing something.
	std::cout << "PPG algorithm"<< std::endl;
	
	cv::VideoCapture cap;
	cap.open(0);
	if (!cap.isOpened())
	{
		//Check if we can access the camera
		std::cerr<<"[ERROR] unable to open camera!"<<std::endl;
		return -2;
	}
		
	cv::CascadeClassifier faceDetector;
	if(!faceDetector.load("./haarcascade_frontalface_alt.xml"))
	{
		std::cerr<<"[ERROR] Unable to load face cascade"<<std::endl;
		return -1;
	};	
		
	while (true)
	{
		if(isDiscardData)
		{
			countDiscard++;
			if (countDiscard == DISCARD_DURATION*FPS)
			{
				isDiscardData=false;
			}
		}
		else
		{
			//Create a matrix to store the image from the cam
			cv::Mat frame;
			//Wait for a new frame from camera and store it into "frame"
			cap.read(frame);
		
			//Check if we succeeded
			if (frame.empty())
			{
				std::cerr<<"[ERROR] Blank frame grabbed"<<std::endl;
				break;
			}
			cv::imshow("Color", frame);
			if (cv::waitKey(1000.0/FPS)>=0)
			{ 
			break;
			}
			
			cv::Mat frame_gray;
			cv::cvtColor(frame, frame_gray, cv::COLOR_BGR2GRAY);
			cv::imshow("Gray", frame_gray);
			std::vector<cv::Rect> faceRectangles;
			faceDetector.detectMultiScale(frame_gray, faceRectangles, 1.1, 3, 0, cv::Size(20,20));
		}
	}	
}