package com.codecool.mergesort;

public class MergeSortSecond {

    public static void main(String[] args) {
        int[] testArray = {2,6,1,20,52,32,8};

        printArray(mergeSort(testArray));
    }

    private static void printArray(int[] array) {
        for (int i: array) {
            System.out.println(i);
        }
    }

    private static int[] mergeSort(int[] arrayToSort) {

        if (arrayToSort.length <= 1) {
            return arrayToSort;
        }

        int midPointer = arrayToSort.length / 2;

        int[] left = new int[midPointer];
        int[] right = new int[arrayToSort.length - midPointer];

        for (int i = 0; i < midPointer; i ++) {
            left[i] = arrayToSort[i];
        }

        for (int j = 0; j < right.length; j ++) {
            right[j] = arrayToSort[midPointer + j];
        }

        int[] result;

        left = mergeSort(left);
        right = mergeSort(right);

        result = merge(left, right);

        return result;

    }

    private static int[] merge(int[] left, int[] right) {
        int[] result = new int[left.length + right.length];

        int leftPointer = 0;
        int rightPointer = 0;
        int resultPointer = 0;

        while (leftPointer < left.length || rightPointer < right.length) {
            if (leftPointer < left.length && rightPointer < right.length) {

                if (left[leftPointer] < right[rightPointer]) {
                    result[resultPointer++] = left[leftPointer++];
                } else {
                    result[resultPointer++] = right[rightPointer++];
                }

            } else if (leftPointer < left.length) {
                result[resultPointer++] = left[leftPointer++];
            } else if (rightPointer < right.length) {
                result[resultPointer++] = right[rightPointer++];
            }
        }

        return result;

    }


}