/*
 * UserList.java 
 */
package project1;

import java.awt.*;
import java.util.*;

public class UserList extends java.awt.List {
   protected Hashtable vid2name = new Hashtable();
   protected Hashtable name2vid = new Hashtable();

   UserListObserver    observer;

   public UserList(UserListObserver observer) {
      this.observer = observer;
   }

   public synchronized void addUser(int vid, String name) {
       if(name.compareTo("")!=0 && name!=null) {
           String oldName = (String) vid2name.get(new Integer(vid));
           if (oldName != null) {
              name2vid.remove(oldName);
              replaceItem(name, findItem(oldName));
           } else {
              vid2name.put(new Integer(vid), name);
              addItem(name);
           }
           vid2name.put(new Integer(vid), name);
           name2vid.put(name, new Integer(vid));
       }
   }

   public synchronized void addPrefix(int vid, String prefix) {
      String oldName = (String) vid2name.get(new Integer(vid));
      if (oldName != null) {
         name2vid.remove(oldName);
         replaceItem(prefix+oldName, findItem(oldName));
      }
      vid2name.put(new Integer(vid), prefix+oldName);
      name2vid.put(prefix+oldName, new Integer(vid));
   }

   public synchronized void subtractPrefix(int vid, int startOffset) {
      String oldName = (String) vid2name.get(new Integer(vid));
      if (oldName != null) {
         name2vid.remove(oldName);
         replaceItem(oldName.substring(startOffset), findItem(oldName));
      }
      vid2name.put(new Integer(vid), oldName.substring(startOffset));
      name2vid.put(oldName.substring(startOffset), new Integer(vid));
   }

   public synchronized void removeUser(int vid) {
      String name = (String) vid2name.get(new Integer(vid));
      int pos = findItem(name);
      if (pos >= 0) {
         if (pos == getSelectedIndex()) {
            observer.onUserListDeselect();
         }
         delItem(pos);
         vid2name.remove(new Integer(vid));
         name2vid.remove(name);
      }
   }

   public synchronized void removeAllUsers() {
      clear();
      vid2name.clear();
      name2vid.clear();
   }

   public void selectUser(int vid) {
      int   pos = findItem((String) vid2name.get(new Integer(vid)));

      if (pos >= 0) {
         select(pos);
         observer.onUserListSelect(vid);
      }
   }

   // return the VID of the currently selected
   // item, or -1 if nothing selected
   private int getSelectedUser() {
      return ((Integer) name2vid.get(getSelectedItem())).intValue();
   }

   private int findItem(String name) {
      for (int i = 0; i < countItems(); i++) {
         if (getItem(i).equals(name)) return i;
      }
      return -1;
   }

   public String getUserName(int vid) {
      return ((String) vid2name.get(new Integer(vid)));
   }

   public boolean handleEvent(Event evt) {
      switch (evt.id) {
      case Event.LIST_SELECT:
         observer.onUserListSelect(getSelectedUser());
         return true;
      case Event.LIST_DESELECT:
         observer.onUserListDeselect();
         return true;
      default:
         return super.handleEvent(evt);
      }
   }
}