package utils;

import java.awt.image.BufferedImage;

public class sobel {
	
	static double  Gx[][];
	static double Gy[][];
	
	public static double [][] Sobel_Gx () {
		return Gx;
	}
	
	public static double [][] Sobel_Gy () {
		return Gy;
	}
	
	public static void appy_sobel (BufferedImage image) {
		int i, j;
		int width = image.getWidth();
		int height = image.getHeight();
		Gx = new double[height][width];
		Gy = new double[height][width];
		
		int[][] img = readLuminance (image);
		double[] I = new double[height*width];
		double[] T = new double[height*width];
		double[][] F = new double[height][width];
		
		int k = 0;
		for (i = 0; i < height; i++) {	
			for (j = 0; j < width; j++) {
				I[k] = (double)(img[i][j])/255.0;
				F[i][j] = (double)(img[i][j])/255.0;
				k++;
			}
		}
		
		image_functions.write_pgm (I, width, height, 0, 1, "Norm");
		
		/*GaussianFilter filter = new GaussianFilter(5);
		filter.filter (I, T, width, height);	
		image_functions.write_pgm (T, width, height, 0, 1, "FILTER");
		k = 0;
		for (i = 0; i < height; i++) {	
			for (j = 0; j < width; j++) {
				F[i][j] = T[k];
				k++;
			}
		}*/
		
		/*double[][]Lala = Gaussian.smooth(F, height, width, 9, 0.0);
		
		image_functions.write_pgm (Lala, width, height, 0, 255, "Filter");*/

		for (i=0; i < height; i++) {
			for (j=0; j < width; j++) {				
				if (i==0 || i==height-1 || j==0 || j==width-1)
					Gx[i][j] = Gy[i][j] = 0; // Image boundary cleared
				else{
					Gy[i][j] = 3*F[i+1][j-1] + 10*F[i+1][j] + 3*F[i+1][j+1] -
					3*F[i-1][j-1] - 10*F[i-1][j] - 3*F[i-1][j+1];
					Gx[i][j] = 3*F[i-1][j+1] + 10*F[i][j+1] + 3*F[i+1][j+1] -
					3*F[i-1][j-1] - 10*F[i][j-1] - 3*F[i+1][j-1];
				}
			}
		}
	}

	private static int[][] readLuminance (BufferedImage image) {
		int width = image.getWidth();
		int height = image.getHeight();
		int picsize = width * height;
		int type = image.getType();
		int[][] data = new int[height][width];
		if (type == BufferedImage.TYPE_INT_RGB || type == BufferedImage.TYPE_INT_ARGB) {
			int[] pixels = (int[]) image.getData().getDataElements(0, 0, width, height, null);
			for (int i = 0; i < picsize; i++) {
				int p = pixels[i];
				int r = (p & 0xff0000) >> 16;
				int g = (p & 0xff00) >> 8;
				int b = p & 0xff;
				int col = i % width;
				int row = i / width;
				data[row][col] = luminance(r, g, b);
			}
		} else if (type == BufferedImage.TYPE_BYTE_GRAY) {
			byte[] pixels = (byte[]) image.getData().getDataElements(0, 0, width, height, null);
			for (int i = 0; i < picsize; i++) {
				int col = i % width;
				int row = i / width;
				data[row][col] = (pixels[i] & 0xff);
			}
		} else if (type == BufferedImage.TYPE_USHORT_GRAY) {
			short[] pixels = (short[]) image.getData().getDataElements(0, 0, width, height, null);
			for (int i = 0; i < picsize; i++) {
				int col = i % width;
				int row = i / width;
				data[row][col] = (pixels[i] & 0xffff) / 256;
			}
		} else if (type == BufferedImage.TYPE_3BYTE_BGR) {
            byte[] pixels = (byte[]) image.getData().getDataElements(0, 0, width, height, null);
            int offset = 0;
            for (int i = 0; i < picsize; i++) {
                int b = pixels[offset++] & 0xff;
                int g = pixels[offset++] & 0xff;
                int r = pixels[offset++] & 0xff;
                int col = i % width;
				int row = i / width;
                data[row][col] = luminance(r, g, b);
            }
        } else {
			throw new IllegalArgumentException("Unsupported image type: " + type);
		}
		return data;
	}
	
	private static int luminance(float r, float g, float b) {
		return Math.round(0.299f * r + 0.587f * g + 0.114f * b);
	}

}