#include <SFML/Graphics.hpp>
#include <iostream>

const int WIDTH = 640;
const int HEIGHT = 480;

sf::Image blackWhite(sf::Image& image)
{
	int width = image.getSize().x;
	int height = image.getSize().y;
	const sf::Uint8* pixels = image.getPixelsPtr();
	sf::Uint8* newPixels = new sf::Uint8[width * height * 4];

	for (int i = 0; i < width*height*4; i+=4)
	{
		int red = pixels[i];
		int green = pixels[i+1];
		int blue = pixels[i+2];

		int val = (red + green + blue) / 3;
		newPixels[i] = val;
		newPixels[i + 1] = val;
		newPixels[i + 2] = val;
		newPixels[i + 3] = 255;
	}

	sf::Image result;
	result.create(width, height, newPixels);

	return result;
}

sf::Image boxFilter(sf::Image& image, double kernel[])
{
	int width = image.getSize().x;
	int height = image.getSize().y;
	const sf::Uint8* pixels = image.getPixelsPtr();
	sf::Uint8* newPixels = new sf::Uint8[(width-2) * (height-2) * 4];

	int c = 0;
	for (int j = 1; j < height-1; ++j)
	{
		for (int i = 1; i < width-1; ++i)
		{
			double r = 0;
			r += pixels[4 * ((j - 1) * width + i - 1)] * kernel[0] + pixels[4 * ((j - 1) * width + i)] * kernel[1] + pixels[4 * ((j - 1) * width + i + 1)] * kernel[2];
			r += pixels[4 * (j * width + i - 1)] * kernel[3] + pixels[4 * (j * width + i)] * kernel[4] + pixels[4 * (j * width + i + 1)] * kernel[5];
			r += pixels[4 * ((j + 1) * width + i - 1)] * kernel[6] + pixels[4 * ((j + 1) * width + i)] * kernel[7] + pixels[4 * ((j + 1) * width + i + 1)] * kernel[8];

			double g = 0;
			g += pixels[4 * ((j - 1) * width + i - 1)+1] * kernel[0] + pixels[4 * ((j - 1) * width + i)+1] * kernel[1] + pixels[4 * ((j - 1) * width + i + 1)+1] * kernel[2];
			g += pixels[4 * (j * width + i - 1)+1] * kernel[3] + pixels[4 * (j * width + i)+1] * kernel[4] + pixels[4 * (j * width + i + 1)+1] * kernel[5];
			g += pixels[4 * ((j + 1) * width + i - 1)+1] * kernel[6] + pixels[4 * ((j + 1) * width + i)+1] * kernel[7] + pixels[4 * ((j + 1) * width + i + 1)+1] * kernel[8];

			double b = 0;
			b += pixels[4 * ((j - 1) * width + i - 1)+2] * kernel[0] + pixels[4 * ((j - 1) * width + i)+2] * kernel[1] + pixels[4 * ((j - 1) * width + i + 1)+2] * kernel[2];
			b += pixels[4 * (j * width + i - 1)+2] * kernel[3] + pixels[4 * (j * width + i)+2] * kernel[4] + pixels[4 * (j * width + i + 1)+2] * kernel[5];
			b += pixels[4 * ((j + 1) * width + i - 1)+2] * kernel[6] + pixels[4 * ((j + 1) * width + i)+2] * kernel[7] + pixels[4 * ((j + 1) * width + i + 1)+2] * kernel[8];

			newPixels[c] = (int)r;
			newPixels[c + 1] = (int)g;
			newPixels[c + 2] = (int)b;
			newPixels[c + 3] = 255;
			c += 4;
		}
	}

	sf::Image result;
	result.create(width-2, height-2, newPixels);

	return result;
}

int main()
{
	sf::RenderWindow window(sf::VideoMode(WIDTH, HEIGHT), "Machine Vision");

	sf::Image image;
	image.loadFromFile("trump.jpg");
	sf::Texture texture;
	texture.loadFromImage(image);
	sf::Sprite sprite;
	sprite.setTexture(texture);

	while (window.isOpen())
	{
		sf::Event event;
		while (window.pollEvent(event))
		{
			if (event.type == sf::Event::Closed)
				window.close();

			if (event.type == sf::Event::KeyPressed)
			{
				if (sf::Keyboard::isKeyPressed(sf::Keyboard::Num0))
				{
					image.loadFromFile("trump.jpg");
					texture.update(image);
				}

				if (sf::Keyboard::isKeyPressed(sf::Keyboard::Num1))
				{
					image = blackWhite(image);
					texture.update(image);
				}

				if (sf::Keyboard::isKeyPressed(sf::Keyboard::Num2))
				{
					double kernel[9] = { 1.0 / 9,1.0 / 9,1.0 / 9,1.0 / 9,1.0 / 9,1.0 / 9,1.0 / 9,1.0 / 9,1.0 / 9 };
					image = boxFilter(image, kernel);
					texture.update(image);
				}

				if (sf::Keyboard::isKeyPressed(sf::Keyboard::Num3))
				{
					double kernel[9] = { 1, 2, 1, 0, 0, 0, -1, -2, -1 };
					image = boxFilter(image, kernel);
					texture.update(image);
				}
			}
		}

		window.clear();
		window.draw(sprite);
		window.display();
	}

	return 0;
}