import java.util.Arrays; 
import java.util.Scanner;

/* This Java application program is for the purpose of testing the
** ParallelMinMax class.
**
** Author: R. McCloskey
** Date: May 9, 2023
*/
public class ParMinMaxTester {

   public static void main(String[] args) {

      Scanner keyboard = new Scanner(System.in);
      int aryLen = getIntInput(keyboard, "Enter array length: ");
      int lowBound = getIntInput(keyboard, "Enter lower bound value: ");
      int upperBound = getIntInput(keyboard, "Enter upper bound value: ");
      int seed = getIntInput(keyboard, "Enter random seed: ");

      RandIntArrayMaker riam = new RandIntArrayMaker();

      // Make an array filled with random integers in accord with
      // parameters entered by user.
      int[] ary = riam.randomIntArray(aryLen, lowBound, upperBound, seed);

      System.out.printf("Array: %s\n", Arrays.toString(ary));

      ParallelMinMax pmm = new ParallelMinMax(ary);
      pmm.computeMinMax();

      System.out.print("\nParallelMinMax reports that the min and max are ");
      System.out.printf("%d and %d\n", pmm.minimumOf(), pmm.maximumOf());

      int minVal = ary[indexOfMin(ary,0,ary.length)];
      if (pmm.minimumOf() != minVal) {
         System.out.printf("***ERROR; actual minimum is %d\n", minVal);
      }

      int maxVal = ary[indexOfMax(ary,0,ary.length)];
      if (pmm.maximumOf() != maxVal) {
         System.out.printf("***ERROR; actual maximum is %d\n", minVal);
      }
   }

   /* Returns the location, within b[floor..ceiling), of the minimum
   ** value in that array segment.
   ** pre: 0 <= floor < ceiling <= b.length
   */
   private static int indexOfMin(int[] b, int floor, int ceiling) {
      int locOfMinSoFar = floor;
      // loop invariant: 
      //    the minimum value in b[floor..i) is at location locOfMinSoFar
      for (int i = floor+1; i != ceiling; i++) {
         if (b[i] < b[locOfMinSoFar]) { locOfMinSoFar = i; }
      }
      return locOfMinSoFar;
   }

   /* Returns the location, within b[floor..ceiling), of the maximum
   ** value in that array segment.
   ** pre: 0 <= floor < ceiling <= b.length
   */
   private static int indexOfMax(int[] b, int floor, int ceiling) {
      int locOfMaxSoFar = floor;
      // loop invariant: 
      //    the maximum value in b[floor..i) is at location locOfMaxSoFar
      for (int i = floor+1; i != ceiling; i++) {
         if (b[i] > b[locOfMaxSoFar]) { locOfMaxSoFar = i; }
      }
      return locOfMaxSoFar;
   }



   /* Displays the specified prompt and then returns the response read
   ** from the specified Scanner (which is assumed to be in a form that 
   ** can be interpreted as an integer).
   */
   private static int getIntInput(Scanner scanner, String prompt) {
      System.out.print(prompt);
      return scanner.nextInt();
   }

}