import java.util.Scanner;
import java.io.File;
import java.io.FileNotFoundException;

/* Java application for purpose of testing the behavior of objects from the
** TimeOfDay class.
**
** Author: R. McCloskey, August 2025
*/
public class TimeOfDayTester {

   private static Scanner input;
   private static boolean echo;
   private static boolean keepGoing;
   private static TimeOfDay time;
   private static TimeOfDay oneTime = new TimeOfDay(8, 23, true);
   private static TimeOfDay anotherTime = new TimeOfDay(5, 17, false);

   public static void main(String[] args) throws FileNotFoundException {
      System.out.println("Welcome to the TimeOfDayTester program.\n");
   
      // Establish the source of input to which the Scanner is attached.
      // If a command line argument is provided, it is taken to be the
      // name of a file from which to read input.  Otherwise input is
      // read from the keyboard.
      establishInputSource(args);
   
      // Establish the initial "current" time of day
      time = makeTimeOfDay();

      System.out.printf("After initialization, time is %s\n\n", time);
   
      printHelp();

      keepGoing = true;
      while (keepGoing) {
         try {
            performCommand();
         }
         catch (Exception e) {
            e.printStackTrace(System.out);
         }
      }
      System.out.println("Goodbye.");
   }

   private static void performCommand() {
      String spacesPattern = " +";
      System.out.print("\n> ");  // prompt for input
      String commandLine = input.nextLine().toUpperCase();  // read line of input
      if (echo) { System.out.println(commandLine); }
      Scanner comLineScanner = new Scanner(commandLine);
      if (!comLineScanner.hasNext())
         { }   // empty command
      else {
         String command = comLineScanner.next();
         if (command.equals("Q")) { keepGoing = false; }
         else if (command.equals("H")) { printHelp(); }
         else if (command.equals("FM")) { testGoForwardByMinute(); }
         else if (command.equals("BM")) { testGoBackwardsByMinute(); }
         else if (command.equals("FH")) { testGoForwardByHour(); }
         else if (command.equals("BH")) { testGoBackwardsByHour(); }
         else if (command.equals("E")) { 
            testIsEarlierThan(oneTime); 
            testIsEarlierThan(anotherTime); 
         }
         else if (command.equals("24")) { testToString24Format(); }
         else { System.out.println("Unknown command; ignoring."); }
      }
   }

   private static void printHelp() {
      System.out.println("Available commands:");
      System.out.println("-------------------");
      System.out.println("  Q        (Quit)");
      System.out.println("  H        (Help)");
      System.out.println("  FM       (test goForwardByMinute())");
      System.out.println("  FH       (test goForwardByHour())");
      System.out.println("  BM       (test goBackwardsByMinute())");
      System.out.println("  BH       (test goBackwardsByHour())");
      System.out.println("  E        (test isEarlierThan())");
      System.out.println("  24       (test toString24Format())");
   }


   /* Compares 'time' with the specified time of day and reports the result.
   */
   private static void testIsEarlierThan(TimeOfDay otherTime) {
      boolean result = time.isEarlierThan(otherTime);
      String emptyOrNOT = result ? "" : " NOT";
      System.out.printf("isEarlierThan() says that %s is%s earlier than %s", 
                        time, emptyOrNOT, otherTime); 
      System.out.println();
   }


   private static void testGoForwardByMinute() {
      time.goForwardByMinute();
      System.out.printf("After calling goForwardByMinute(), the time is %s\n", time);
   }

   private static void testGoBackwardsByMinute() {
      time.goBackwardsByMinute();
      System.out.printf("After calling goBackwardsByMinute(), the time is %s\n", time);
   }

   private static void testGoForwardByHour() {
      time.goForwardByHour();
      System.out.printf("After calling goForwardByHour(), the time is %s\n", time);
   }

   private static void testGoBackwardsByHour() {
      time.goBackwardsByHour();
      System.out.printf("After calling goBackwardsByHour(), the time is %s\n", time);
   }

   private static void testToString24Format() {
      System.out.printf("The 24-hour format for %s is %s\n", time, time.toString24Format());
   }


   /* Returns a new TimeOfDay object set to the time of day specified by
   ** the three inputs obtained via the 'input' Scanner.
   */
   private static TimeOfDay makeTimeOfDay() {
      TimeOfDay result = null;
      
      String timeStr = 
         getInput("Enter time of day (e.g., 5:46AM, 12:07PM): ").trim();
      try {
         int posOfColon = timeStr.indexOf(':');
         int h = Integer.parseInt(timeStr.substring(0,posOfColon));
         int m = Integer.parseInt(timeStr.substring(posOfColon+1,posOfColon+3));
         String amOrPm = timeStr.substring(posOfColon+3).toUpperCase();
         if (amOrPm.equals("AM")) { result = new TimeOfDay(h,m,true); } 
         else if (amOrPm.equals("PM")) { result = new TimeOfDay(h,m,false); } 
         else { 
            result = new TimeOfDay();
            System.out.println("Invalid string; initializing to noon");
         }
      }
      catch (Exception e) {
         e.printStackTrace(System.out);
         System.out.println("\nInvalid input: Program aborting.");
         System.exit(0);
      }
      return result;
   }

   private static String getInput(String prompt) {
      System.out.print(prompt);
      String result = input.nextLine();
      if (echo) { System.out.println(result); }
      return result;
   }

   /* Establishes the source of input from which the Scanner ('input') 
   ** will read.  If args[] is not empty, the file whose name is args[0]
   ** will be the input source.  Otherwise it will be the keyboard.
   */
   private static void establishInputSource(String[] args) throws FileNotFoundException {
      if (args.length != 0) {
         input = new Scanner(new File(args[0]));
         echo = true;
      }
      else {
         input = new Scanner(System.in);
         echo = false;
      }
   }
}