package arrayplay;

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

public class WordList {

           /**
           * @param args the command line arguments
           */
    private static final int LIMIT = 1000;
       private static String[] words = new String[LIMIT];
        private static int numberOfWords = 0;
       private static Scanner commandReader = new Scanner(System.in);


              public static void main(String[] args) {
                  try {
                           //ESTABLISH ARRAY OF WORDS
                           readWords();
                           // CHECK THE DATA
                           //System.out.println("\nThe original list of words ...");
                           //displayWords();
                           //ENTER THE INTERPRETER
                           interpreter();
                       } catch (FileNotFoundException ex) {
                           System.out.println("The file was not found. Please think again.");
                           System.exit(-1);
                       }
               }

                // Assuming that the data file will be found in the public_html/data
                // subdirectory of the user's home directory
                private static Scanner establishScanner(String fn) throws FileNotFoundException {
                   String separator = System.getProperty("file.separator");
                   String homeDirectory = System.getProperty("user.home");
                   String path = homeDirectory + separator + "CS1Files" + separator + "data" + separator;
                  String fullFileName = path + fn;
                   return new Scanner(new File(fullFileName));
               }
        private static void readWords() throws FileNotFoundException {
                   Scanner scanner = establishScanner("WordSet.txt");
                   while (scanner.hasNext()) {
                           words[numberOfWords] = scanner.next();
                           numberOfWords ++;
                       }
               }

                private static void displayWords() {
                   for (int x = 0; x < numberOfWords; x ++) {
                           System.out.println(words[x]);
                       }
               }

                private static void interpreter() {
                  System.out.print(">>>");
                  String command = commandReader.next();
                   if (command.equalsIgnoreCase("DISPLAY")) {
                          interpreterDisplayCommand();
                       } else if (command.equalsIgnoreCase("PRINT")) {
                          interpreterPrintCommand();
                       } else if (command.equalsIgnoreCase("SWAP")) {
                           interpreterSwapCommand();
                       } else if (command.equalsIgnoreCase("ADD")) {
                           interpreterAddCommand();
                       } else if (command.equalsIgnoreCase("HELP")) {
                           interpreterHelpCommand();
                       } else if (command.equalsIgnoreCase("EXIT")) {
                           System.exit(0);
                      } else {
                           System.out.println("### Unrecognizable command: " + command);
                       }
                   System.out.print("\n");
                   interpreter();
              }

                private static void interpreterDisplayCommand() {

                  displayWords();
               }

                private static void interpreterPrintCommand() {
                   String operand = commandReader.next();
                   if (operand.equalsIgnoreCase("FIRST")) {
                           System.out.println(words[0]);
                       } else {
                          int index = Integer.valueOf(operand);
                          System.out.println(words[index-1]);
                      }
              }

              private static void interpreterSwapCommand() {
                  int position1 = commandReader.nextInt();
                  int position2 = commandReader.nextInt();
                  String temp = words[position1 - 1];
                  words[position1 - 1] = words[position2 - 1];
                  words[position2 - 1] = temp;
              }

              private static void interpreterAddCommand() {
                  String position = commandReader.next();
                  if (position.equalsIgnoreCase("LAST")) {
                          addLast();
                      } else if (position.equalsIgnoreCase("FIRST")) {
                          addFirst();
                      } else {
                         System.out.println("### Invalid operand for add command");
                      }
                  numberOfWords ++;
              }

              private static void interpreterHelpCommand() {
                  System.out.println("HELP    - display menu of commands");
                  System.out.println("DISPLAY - display the list of words");
                  System.out.println("PRINT   - print a word (FIRST; LAST; nth)");
                 System.out.println("SWAP    - exchange two elements (nth; mth)");
                  System.out.println("ADD     - add a word to the list (FIRST; LAST)");
                  System.out.println("EXIT    - terminate execution of the program");
              }

              private static void addFirst() {
                 for (int x = numberOfWords; x > 0; x --) {
                          words[x] = words[x - 1];
                      }
                  words[0] = commandReader.next();
              }

              private static void addLast() {
                  words[numberOfWords] = commandReader.next();
             }

         }