import java.awt.List;
import java.awt.image.BufferedImage;
import java.awt.image.DataBuffer;
import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.Scanner;
import java.util.stream.Stream;
import javax.imageio.ImageIO;

public class ImageComparisson {

	public static int number;

	public static ArrayList<String> list = new ArrayList<String>();
	public static ArrayList<Double> PercSim = new ArrayList<Double>();
	public static void print ()
	{

		String[] S = new String[number];
		Double[] Perc = new Double[number];
		for (int i = 0 ; i < number ; i++ ) {

			list.toArray(S);
			PercSim.toArray(Perc);
			System.out.println((i+1) +". "+S[i] +" at "+ Perc[i]+ "% ");
		}
		System.out.println();
	}

	public static void max ()
	{
		String[] S = new String[number];
		Double[] Perc = new Double[number];
		double max = 0;
		int index = 0;

		for (int i = 0 ; i < number ; i++ ) {

			PercSim.toArray(Perc);
			list.toArray(S);
			if (max < Perc[i] && Perc[i] != 100) {
				max = Perc[i];
				index = i;
			}

		}
		System.out.println("The file with maximum similarity is: "+ S[index]+" at "+ Perc[index]+ "%" );
		System.out.println();
	}

	public static void min ()
	{
		String[] S = new String[number];
		Double[] Perc = new Double[number];
		double min = 100;
		int index = 0;

		for (int i = 0 ; i < number ; i++ ) {

			PercSim.toArray(Perc);
			list.toArray(S);
			if (min > Perc[i] && Perc[i] != 100) {
				min = Perc[i];
				index = i;
			}

		}
		System.out.println("The file with minimum similarity is: "+ S[index]+" at "+ Perc[index]+ "%" );
		System.out.println();
	}


	public static double compareImage(File fileA, File fileB, int percent) {

		double percentage = 0.0;
		try {
			// take buffer data from both image files //
			BufferedImage biA = ImageIO.read(fileA);
            DataBuffer dbA = biA.getData().getDataBuffer();
            double sizeA = dbA.getSize();

            BufferedImage biB = ImageIO.read(fileB);
            DataBuffer dbB = biB.getData().getDataBuffer();
            double sizeB = dbB.getSize();

            double count = 0;

            // compare data-buffer objects
            if (sizeA == sizeB) {

            	for (int i = 0; i < sizeA; i++) {
            		//check the first 100 pixels and if at least half the inputed percent of pixels are not the same
            		//move to the next file
            		if ( i == (sizeA / 100) && count < ( (sizeA * percent) / (2 * 100 * 100 ) ) )
            		{
            			return 0;
            		}
            		//check if pixel values are close enough in colour (acceptable range of 20)
            		if (Math.abs( ( dbA.getElem(i) - dbB.getElem(i))) <= 20 )  {
            			count = count + 1;
            		}
            	}

            	//calculate the percentage based on the similar pixels
            	percentage = (count * 100) / sizeA;

            }
            else {

            }

		}
		catch (Exception e) {
			System.out.println("Failed to compare image files ... "  ) ;
			System.out.println(fileB.getPath());
			e.printStackTrace();
		}
		if (percentage >= percent)
		{

			System.out.println("Image file "+ fileB.getPath()+" is similar to reference file" );
			System.out.println("These images are "+  percentage + "% similar" );
			System.out.println();
			list.add(fileB.getPath());
			PercSim.add(percentage);
			number++;
		}
		return 0;
	}




	public static void main(String[] args) throws IOException {

		Scanner sc = new Scanner (System.in);
		Scanner sc2 = new Scanner (System.in);
		Scanner sc3 = new Scanner (System.in);
		System.out.println();

		File fileA = new File("Project_1_datasets\\2\\40694.jpg");
		System.out.println("The reference file is: "+ fileA.getPath());
		System.out.println();

		System.out.print("Enter percent of similarity to search for (0 to 100, recomended 75+ )  : ");
		int percent = sc.nextInt();

		while (percent < 0 || percent > 100)
		{
			System.out.println("Percentage entered not in range, choose a number between 0 to 100");
			percent = sc.nextInt();
		}
		System.out.println();

		int percents = percent;

		System.out.print("Searching for files "+ percents+"% similar to the file "+fileA.getPath());
		System.out.print(" , start search? (Y/N) : ");
		String S = sc2.nextLine();

		while (!S.equals("Y") && !S.equals("y")) {
			System.out.println("Please enter Y");
			S = sc2.nextLine();
		}

		System.out.println();
		System.out.println("Starting the search ...");
		System.out.println();

		try (Stream<Path> filePathStream=Files.walk(Paths.get("Project_1_datasets\\"))) {
			filePathStream.forEach(filePath -> {
				if (Files.isRegularFile(filePath)) {
					File fileB = new File(filePath.toString());
					compareImage(fileA ,fileB, percents);
				}
			});

			System.out.println("Done searching");
			System.out.println("Number of matches : "+ number);
			System.out.println();

			if(number == 0) {
				System.out.println("No matches closing the program ...");
				sc.close();
				sc2.close();
				sc3.close();
			}

			else {

				System.out.print("Print out the list of the " +number+" matching file(s) (Y/N) : ");
				String D = sc3.nextLine();
				while (!D.equals("Y") && !D.equals("N") && !D.equals("n") && !D.equals("y")) {
					System.out.println("Please enter Y or N: ");
					D = sc3.nextLine();
				}
				System.out.println();
				if (D.equals("Y") || D.equals("y")){
					print();
					max();
					min();
				}

				if (D.equals("N") || D.equals("n")) {
				}
				System.out.println("Closing the program ...");
				sc.close();
				sc2.close();
				sc3.close();
			}
		}
	}
}