#include"cover.h"

bool Cover::initConfig(float ratio, float threshold, int blockSize, int size) {
	Size = size;
	BlockSize = blockSize;
	Threshold = threshold;
	Ratio = ratio;
	blocks = size / blockSize;
	x = blockSize * 3 / 4;
	w = blockSize/4;

	return true;
}

int Cover::detect(cv::Mat& image) 
{
	try
	{
		cv::Mat gray, resized;
		int channels = image.channels();
		if (channels == 3) {
			cv::cvtColor(image, gray, cv::COLOR_BGR2GRAY);
			cv::resize(gray, resized, cv::Size(Size, Size));
		}
		else if (channels == 1) {
			cv::resize(image, resized, cv::Size(Size, Size));
		}

		cv::Mat roi, dct_result;
		cv::Rect recth(x, x, w, w);
		//
		float n = 0;
		for (int i = 0; i < blocks; i++) {
			for (int j = 0; j < blocks; j++) {
				cv::Rect rect(i * BlockSize, j * BlockSize, BlockSize, BlockSize);
				roi = resized(rect);
				//roi.convertTo(roi,CV_32FC1,1.0/255);
				roi.convertTo(roi, CV_32FC1);
				cv::dct(roi, dct_result);
				float* data = (float*)dct_result(recth).data;
				float sum = 0;
				for (int i = 0; i < w * w; i++) {
					sum += abs(data[i]);
				}
				float mean = sum / (float)(w * w);
				if (mean < Threshold) {
					n += 1;
				}
			}
		}

		if (n / (float)(blocks * blocks) >= Ratio) {
			return 1;
		}
		else {
			return 0;
		}
	}
	catch (const std::exception& ex)
	{
		std::string errorMessage = "cover-";
		errorMessage += ex.what();
		throw std::runtime_error(errorMessage);
	}
	
}