#include "wvlt_rgb.hpp"
#include "math.hpp"

#include <image_io.hpp>
#include <utilities.hpp>
#include <wvlt/wavelet.hpp>

#include <ostream>
#include <cmath>

namespace fingerprints {

static const int size = 512;

wvlt_rgb::pre_fingerprint wvlt_rgb::pre_calculate(av::frame const & frame) {
	auto const image = to_raw_rgb_image(crop_to_square(frame), size, size);
	wvlt_rgb::pre_fingerprint ret;

	// for every color
	for(unsigned int color = 0; color < 3; ++color){
		auto & vector = ret[color];
		vector.assign(make_u(image.width() * image.height()), 0);

		for(unsigned int n = 0; n < make_u(image.width() * image.height()); ++n){
			vector[n] = 2.0 * image.data[3*n + color] / double(255) - 1.0;
		}

		wvlt::wavelet_2D(vector.data(), make_u(image.width()), make_u(image.height()));
	}

	return ret;
}

wvlt_rgb wvlt_rgb::calculate(av::frame const & frame){
	auto const image = to_raw_rgb_image(crop_to_square(frame), size, size);
	wvlt_rgb ret;

	std::vector<double> vector(make_u(image.width() * image.height()), 0);

	// for every color
	for(unsigned int color = 0; color < 3; ++color){
		auto& coefficient_array = color == 0 ? ret.reds : (color == 1 ? ret.greens : ret.blues);
		unsigned int array_index = 0;

		for(unsigned int n = 0; n < make_u(image.width() * image.height()); ++n){
			vector[n] = 2.0 * image.data[3*n + color] / double(255) - 1.0;
		}

		wvlt::wavelet_2D(vector.data(), make_u(image.width()), make_u(image.height()));

		auto copy = vector;
		for(auto & x : copy) x = std::abs(x);

		auto const n_coefficients = coefficient_array.size();
		std::nth_element(copy.begin(), copy.begin() + n_coefficients, copy.end(), std::greater<double>());
		auto const threshold = copy[n_coefficients-1];

		for(unsigned int n = 0; n < vector.size(); ++n){
			auto const x = vector[n];
			if(std::abs(x) >= threshold) {
				coefficient_array[array_index++] = std::make_pair(n, x);
			}
			if(array_index >= coefficient_array.size()) {
				break;
			}
		}
	}

	return ret;
}

double wvlt_rgb::distance_to(pre_fingerprint const & fingerprint) const {
	double distance = 0;

	for(unsigned int color = 0; color < 3; ++color){
		auto const & coefficients = color == 0 ? reds : (color == 1 ? greens : blues);

		for(auto&& p : coefficients){
			auto const x = p.second;
			auto const y = fingerprint[color][p.first];
			distance += square(x - y) - square(y);
		}
	}

	return distance;
}

} // namespace fingerprints