import java.util.Arrays;

/**
 * Created by Lesley on 18-1-2017.
 */
@SuppressWarnings("Duplicates")
public class BubbleSort4Threads {

    private static int amount = 1000000;
    private static int[] part1 = new int[amount / 4];
    private static int[] part2 = new int[amount / 4];
    private static int[] part3 = new int[amount / 4];
    private static int[] part4 = new int[amount / 4];
    private static int[] mergeArray1 = new int[amount / 2];
    private static int[] mergeArray2 = new int[amount / 2];
    private static int[] mergeArray3 = new int[amount];

    public static void main(String[] args) throws InterruptedException {
        Sorter s = new Sorter();
        int partOne = (int) (amount * 0.25);
        int partTwo = (int) (amount * 0.50);
        int partThree = (int) (amount * 0.75);

        int[] array = s.randomArray(amount);
        part1 = Arrays.copyOfRange(array, 0, partOne);
        part2 = Arrays.copyOfRange(array, partOne, partTwo);
        part3 = Arrays.copyOfRange(array, partTwo, partThree);
        part4 = Arrays.copyOfRange(array, partThree, array.length);

        long startTime = System.nanoTime();
        Thread t1 = new Thread(() -> {
            sortArray(part1.length, part1);
        });
        Thread t2 = new Thread(() -> {
            sortArray(part1.length, part2);
        });
        Thread t3 = new Thread(() -> {
            sortArray(part1.length, part3);
        });
        Thread t4 = new Thread(() -> {
            sortArray(part1.length, part4);
        });

        t1.start();
        t2.start();
        t3.start();
        t4.start();
        t1.join();
        t2.join();
        t3.join();
        t4.join();

        mergeArray(part1, part2, mergeArray1);
        mergeArray(part3, part4, mergeArray2);
        mergeArray(mergeArray1, mergeArray2, mergeArray3);

        long endTime = System.nanoTime() - startTime;
        double seconds = (double) endTime / 1000000000.0;
        System.out.println("\nBubble Sorted Array - Parallel, took: " + seconds + " seconds");

        System.out.println("+++++++++\n");
        for(int i : mergeArray3)
            System.out.print(i + " ");
    }

    static private void sortArray(int n, int[] array) {
        int c, d, swap;
        for (c = 0; c < (n - 1); c++) {
            for (d = 0; d < n - c - 1; d++) {
                if (array[d] > array[d + 1]) /* For descending order use < */ {
                    swap = array[d];
                    array[d] = array[d + 1];
                    array[d + 1] = swap;
                }
            }
        }
    }

    static private int[] mergeArray(int[] part1, int[] part2, int[] mergeArray1) {
        int indexPart1 = 0;
        int indexPart2 = 0;
        int indexPart3 = 0;

        while (indexPart1 < part1.length && indexPart2 < part2.length) {
            if (part1[indexPart1] < part2[indexPart2]) {
                mergeArray1[indexPart3] = part1[indexPart1];
                indexPart1++;
            } else {
                mergeArray1[indexPart3] = part2[indexPart2];
                indexPart2++;
            }
            indexPart3++;
        }

        if (indexPart1 < part1.length) {
            for (int z = indexPart1; z < part1.length; z++, indexPart3++) {
                mergeArray1[indexPart3] = part1[z];
            }
        }

        if (indexPart2 < part2.length) {
            for (int z = indexPart2; z < part2.length; z++, indexPart3++) {
                mergeArray1[indexPart3] = part2[z];
            }
        }

        return mergeArray1;
    }
}