// Arup Guha
// 7/5/04
// PhoneBook: Part of the solution for the 2004 BHCSI pre-test problem.
//            This class manages a phonebook of up to 10 entries, using
//            an array of PhoneBookEntry objects. A main is included that
//            allows the user to create their own PhoneBook object and
//	      add entries, as well as a few other tasks.

import java.io.*;
import java.util.Scanner;

public class PhoneBook {

  private PhoneBookEntry[] book;
  private int cur_entry;

  // Creates an empty PhoneBook object.
  public PhoneBook() {
    book = new PhoneBookEntry[10];
    cur_entry = 0;
  }

  // Returns true iff the current object is full.
  public boolean full() {
    return (cur_entry == 10);
  }

  // Adds the entry e into the current object, returning true if the add
  // was done successfully. If false is returned, no entry is added to the
  // current object.
  public boolean add(PhoneBookEntry e) {
    if (cur_entry == 10) return false;

    book[cur_entry] = e;
    cur_entry++;
    return true;
  }

  // Prints out the entire object.
  public void printBook() {

    System.out.println("Here are all the current entries:");
    for (int i=0; i<cur_entry; i++) 
      System.out.println(i+". "+book[i]);
  }

  // Prints out all entries that have the last name lastname.
  public void search(String lastname) {

    for (int i=0; i<cur_entry; i++) 
      if (book[i].sameLastName(lastname))
        System.out.println(i+". "+book[i]);
  }

  // Returns the number of entries with the last name lastname.
  public int searchNumMatches(String lastname) {

    int cnt = 0;
    for (int i=0; i<cur_entry; i++) 
      if (book[i].sameLastName(lastname))
        cnt++;
    return cnt;
  }

  // Returns the index of the first entry in the current object with the
  // last name lastname. If no such entry exists, -1 is returned.
  public int getIndex(String lastname) {

    for (int i=0; i<cur_entry; i++) 
      if (book[i].sameLastName(lastname))
        return i;
    return -1;
  }

  // Changes the last name of entry index to newlastname.
  public void changeLastName(int index, String newlastname) {
    book[index].changeLastName(newlastname);
  }

  // Changes the phone number of entry index to newnum.
  public void changeNumber(int index, int newnum) {
    book[index].changeNumber(newnum);
  }

  // Prints out the menu for the user.
  public static void menu() {

    System.out.println("Here are your options:");
    System.out.println("1. Add an entry to the phonebook.");
    System.out.println("2. Print out all phonebook entries.");
    System.out.println("3. Search for an entry.");
    System.out.println("4. Change the last name of an entry.");
    System.out.println("5. Change the phone number of an entry.");
    System.out.println("6. Quit.");

  }

  // Asks the user for the entry to change and executes the change.
  public void doChangeName(Scanner stdin) throws IOException {

    // Find the last name of the entry to change.
    System.out.println("What is the last name you want to change?");
    String last = stdin.next();
    int nummatches = searchNumMatches(last);

    // No matching entries.
    if (nummatches == 0)
      System.out.println("Sorry no entries match that last name.");

    // Exactly one match found.
    else if (nummatches == 1) {
      System.out.println("Exactly one entry matched:");
      search(last);

      // Get and set the new last name.
      System.out.println("What is the new last name?");
      String newln = stdin.next();
      changeLastName(getIndex(last), newln);
    }

    // Multiple matches found.
    else {
          
      System.out.println("Here are the matching entries:");
      search(last);

      // Get the appropriate entry.
      System.out.println("Enter the number of the entry you want to change.");
      int changei = stdin.nextInt();

      // Get and set the new last name.
      System.out.println("What is the new last name?");
      String newln = stdin.next();
      changeLastName(changei, newln); 
    }
  }

  // Asks the user for the entry to change and executes the change.
  public void doChangeNumber(Scanner stdin) throws IOException {

    // Asks for the last name of the entry to change.
    System.out.println("What is the last name for the number you want to change?");
    String last = stdin.next();
    int nummatches = searchNumMatches(last);

    // No matching entries.
    if (nummatches == 0)
      System.out.println("Sorry no entries match that last name.");

    // Exactly one match.
    else if (nummatches == 1) {
      System.out.println("Exactly one entry matched:");
      search(last);

      // Get and set the new number.
      System.out.println("What is the phone number?");
      int num = stdin.nextInt();
      changeNumber(getIndex(last), num);
    }

    // Multiple matching entries.
    else {

      // Get the exact entry to change.
      System.out.println("Here are the matching entries:");
      search(last);
      System.out.println("Enter the number of the entry you want to change.");
      int changei = stdin.nextInt();

      // Get and set the new number.
      System.out.println("What is the new phone number?");
      int num = stdin.nextInt();
      changeNumber(changei, num); 
    }
  }

  public static void main(String[] args) throws IOException {

    Scanner stdin = new Scanner(System.in);

    PhoneBook book = new PhoneBook(); // PhoneBook object to use.

    menu();
    int ans = stdin.nextInt();

    // Loop until the user quits.
    while (ans != 6) {

      // Execute the add option.
      if (ans == 1) {
        if (book.full()) 
          System.out.print("Sorry, the phonebook is full, no entry can be added");  
        else {
          PhoneBookEntry e = PhoneBookEntry.getEntry();
          book.add(e);
          System.out.println("The entry has been added.");
        }
      }

      // Print out the Phone Book.
      else if (ans == 2)
        book.printBook();

      // Execute a search on the phone book.
      else if (ans == 3) {
        System.out.println("What is the last name for your search?");
        String last = stdin.next();
        if (book.searchNumMatches(last) > 0) {
          System.out.println("Here are the entries the matched your search.");
          book.search(last);
        }
        else
          System.out.println("Sorry, no entries matched your search.");
      }

      else if (ans == 4) 
        book.doChangeName(stdin);
      
      else if (ans == 5) 
        book.doChangeNumber(stdin);
      
      else if (ans != 6) 
        System.out.println("Sorry that is an invalid menu choice.\n");

      menu();
      ans = stdin.nextInt();

    }

  }
}