Bubble Sort in Kotlin

BubbleSort.kt

/**
 * Complexity O(n^2)
 */

/**
 * Unsorted Data Source
 */
var unsortedArray: ArrayList<Int> = arrayListOf(45,7,3,6,12,657,568,23412,3,46,647,234,7687,686,235,564,768568,345,23,1,23,3,46,7,8,945,34)

fun main() {
    //print out the sorted array returned from function  
    System.out.print(bubbleSort(unsortedArray))
}


//gets input of unsorted Array and returns sorted Array
fun bubbleSort(array: ArrayList<Int>): ArrayList<Int>{
    //if array is empty or array.size is 1 simpley return the array
    if(array.isEmpty() || array.size == 1){
        return array
    }else{
      for(indexA in 0 until array.size - 1){
           for(indexB in 0 until (array.size - indexA -1)){
               if(array[indexB] > array[indexB + 1]){
                   //swap values, from array 
                   swap(array, indexB, indexB + 1)
               }
           }
       }
    }
    //after sorting return the array
    return array
}

fun swap(array: ArrayList<Int>, indexA: Int, indexB: Int){
        var tempValue = array[indexA]
        array[indexA] = array[indexB]
        array[indexB] = tempValue
}