import java.util.Scanner;

/* Java application having as its purpose to test the features of the
** IndexedListViaLink1 class.
**
** Author: R. McCloskey
** Date: January 2024
*/

public class IndexedListTester {

   // User commands:
   private static char HELP = 'h';
   private static char QUIT = 'q';
   private static char CREATE = 'c';
   private static char LENGTH = 'L';
   private static char ELEM_AT = 'e';
   private static char DELETE = 'd';
   private static char REPLACE = 'r';
   private static char INSERT = 'i';
   private static char APPEND = 'a';
   private static char INDEX_OF = 'x';
   private static char TSIL = 't';
   private static char PRINT = 'p';

   private static Scanner keyboard = new Scanner(System.in);
   private static boolean keepGoing = true;;
   private static IndexedListViaLink1<String> aList = new IndexedListViaLink1<String>();

   public static void main(String[] args) {
      System.out.println("Welcome to the IndexedListTester program.");
      System.out.println("Enter 'h' for a list of commands.");
      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);

         try {
            performCommand(command);
         }
         catch (Exception e) {
            e.printStackTrace(System.out);
            print("\n Something went wrong; try again\n");
         }
      }
      System.out.println("Goodbye.");
   }

   /* Performs the specified command upon aList.
   */
   private static void performCommand(String command) {
         
      Scanner comScan = new Scanner(command);
      String commandCode = comScan.next();
      if (commandCode.length() != 1) {
         print("Command code must be a single letter; try again.\n");
      }
      else {
         char cc = commandCode.charAt(0);
         if (cc == HELP) {
            printHelp();
         }
         else if (cc == QUIT) {
            keepGoing = false;
         }
         else if (cc == CREATE) {  // create new list
            if (comScan.hasNext()) {
               String[] elems = comScan.nextLine().trim().split(" ");
               aList = new IndexedListViaLink1<String>(elems);
            }
            else {   // create empty list
               aList = new IndexedListViaLink1<String>();
            }
            print("New list created...\n");
            displayList();
         }
         else if (cc == LENGTH) {   // display Length
            System.out.printf("%d\n", aList.lengthOf());
         }
         else if (cc == ELEM_AT) { 
            int k = comScan.nextInt();
            print(aList.elemAt(k) + "\n");
         }
         else if (cc == INDEX_OF) {
            String str = comScan.nextLine().trim();
            int k = aList.indexOf(str);
            print(k + "\n");
         }
         else if (cc == DELETE) {   // delete/remove
            int k = comScan.nextInt();
      
            String deletedStr = aList.remove(k);
            print("Deleted item is " + deletedStr + "\n");
            displayList();
         }
         else if (cc == REPLACE) {   // replace
            int k = comScan.nextInt();
            String str = comScan.nextLine().trim();
            aList.replace(k, str);
            displayList();
         }
         else if (cc == INSERT) {   // insert
            int k = comScan.nextInt();
            String newElem = comScan.next();
            aList.insert(k, newElem);
            displayList();
         }
         else if (cc == APPEND) {   // append
            String newElem = comScan.next();
            aList.append(newElem);
            displayList();
         }
         else if (cc == TSIL) {   // tsil (reverse)
            aList.tsil();
            displayList();
         }
         else if (cc == PRINT) {  // print/display
            if (!comScan.hasNext()) {  // display whole list
               aList.display();
            }
            else {
               int start = comScan.nextInt();
               int stop = comScan.nextInt();
               aList.display(start, stop);
            }
            print("\n");
         }
         else {
            print("Unrecognized command; try again.");
         }
      }
   }

   /* Displays aList.
   */
   private static void displayList() {
      //print("List is now: ");
      aList.display();
      print("\n");
   }

   private static void printHelp() {
      print("Examples of commands:\n");
      print("---------------------\n");
      print(QUIT + " : to quit\n");
      print(HELP + " : to display this list of example commands!\n");
      print(LENGTH + " : to display length of the list\n");
      print(ELEM_AT + " 5 : to display the element at position 5 of the list\n");
      print(INDEX_OF + 
            " cow : to find the position at which \"cow\" occurs in the list\n");
      print(DELETE + " 3 : to delete/remove the element at position 3\n");
      print(REPLACE + 
            " 2 cow : to replace the element at position 2 with \"cow\"\n");
      print(INSERT + " 6 cow : to insert \"cow\" at position 6\n");
      print(APPEND + " moose : to append \"moose\" to the end of the list\n");
      print(PRINT + " : to print/display all list elements\n");
      print(PRINT + 
            " 2 7: to print/display the list elements in positions 2 through 6\n");
      print(CREATE + " dog cat pig : populates new list with three animals\n");
      print(CREATE + " :  makes a new empty list\n");
      print(TSIL + " : to apply tsil() (to reverse the list)\n");
   }


   /* Surrogate for System.out.print()
   */
   private static void print(String s) { System.out.print(s); }

}