import java.util.Scanner;

/* DequeTester.java
** This Java application is for the purpose of testing a class that
** implements the Deque interface.
**
** Author: R. McCloskey
** Date: March 2019
*/

public class DequeTester {

   private static boolean keepGoing;
   private static Scanner keyboard = new Scanner(System.in);

   public static void main(String[] args) {
      System.out.println("Welcome to the Deque Tester!");

      Deque<String> deque = null;
      int k = getInt("Enter 1 to test an array-based deque;\n" +
                     "Enter 2 to test a Link2-based deque\n> ");
      if (k == 1) {
         int cap = getInt("Choose capacity of deque (suggested is 8): ");
         deque = new DequeViaArray<String>(cap);
      }
      else if (k == 2) {
         deque = new DequeViaLink2<String>();
      }
      else {
         System.out.println("Invalid response; program aborting");
         System.exit(0);
      }

      testDeque(deque);
   }

   public static void testDeque(Deque<String> deque) {
      keepGoing = true;
      while (keepGoing) {
         String command;
         // Prompt user until a non-empty string is entered
         do {
            System.out.print("\n>");
            command = keyboard.nextLine().trim();
         }
         while (command.length() == 0);

         // Having received a non-empty command, try to perform it.
         try {
            performCommand(deque, command);
         }
         catch (Exception e) {
            e.printStackTrace(System.out);
            System.out.println("\n Something went wrong; try again");
         }
      }
      System.out.println("Goodbye.");
   }


   /* Applies the command described by the second parameter to the deque
   ** given by the first.
   */
   private static void performCommand(Deque deque, String command) {
      Scanner comScanner = new Scanner(command);
      String commandCode = comScanner.next();
      String insertWarning = "Need to specify a string to insert!";
      
      if (commandCode.equals("q")) {
         keepGoing = false;
      } 
      else if (commandCode.equals("pr")) { 
         System.out.printf("Rear item is %s\n", deque.rearOf());
      }
      else if (commandCode.equals("pf")) { 
         System.out.printf("Front item is %s\n", deque.frontOf());
      }
      else if (commandCode.equals("ps")) { 
         System.out.printf("Size of deque is %s\n", deque.sizeOf());
      }
      else if (commandCode.equals("pd")) { 
         printContents(deque);
         //System.out.printf("Contents of deque: %s\n", deque.toString());
      }
      else if (commandCode.equals("ir")) {    // insert at rear
         if (!comScanner.hasNext()) {
            System.out.println(insertWarning);
         }
         else {
            String item = comScanner.next();
            System.out.printf("Inserting \"%s\" at rear...\n", item);
            deque.insertAtRear(item);
            printContents(deque);
            //System.out.printf("Contents of deque: %s\n", deque.toString());
         }
      }
      else if (commandCode.equals("if")) {    // insert at front
         if (!comScanner.hasNext()) {
            System.out.println(insertWarning);
         }
         else {
            String item = comScanner.next();
            System.out.printf("Inserting \"%s\" at front...\n", item);
            deque.insertAtFront(item);
            printContents(deque);
         }
      }
      else if (commandCode.equals("rr")) {    // remove from rear
         System.out.println("Removing item at rear...");
         deque.removeRear();
         printContents(deque);
      }
      else if (commandCode.equals("rf")) {    // remove from frong
         System.out.println("Removing item at front...");
         deque.removeFront();
         printContents(deque);
      }
      else if (commandCode.equals("h")) { 
         printHelp();
      }
      else {
         System.out.println("Unrecognized command.");
      }
   }

   private static void printHelp() {
      System.out.println("q : to quit");
      System.out.println("h : for help");
      System.out.println("ps : to print size of deque");
      System.out.println("pr : to print item at rear of deque");
      System.out.println("pf : to print item at front of deque");
      System.out.println("pd : to print all items in deque");
      System.out.println("rr : to remove item from rear");
      System.out.println("rf : to remove item from front");
      System.out.println("ir x : to insert string x at rear");
      System.out.println("if x : to insert string x at front");
   }

   private static void printContents(Deque d) {
      System.out.println("Contents of deque: " + d);
   }

   private static int getInt(String prompt) {
      System.out.print(prompt);
      return Integer.parseInt(keyboard.nextLine().trim());
   }

}