public class Roster : Object, Gtk.TreeModel {
  private int stamp;
  private Gee.TreeMap<string, Contact> entries = new Gee.TreeMap<string, Contact>();
  
  
  public Roster() {
    stamp = 0;
  }
  
  public void update_contact(Contact c) {
    ++stamp;
    bool added = !entries.has_key(c.jid);
      
    entries[c.jid] = c;
      
    Gtk.TreeIter iter = Gtk.TreeIter();
    iter.stamp = stamp;
    iter.user_data = this;
    iter.user_data2 = c;
      
    Gtk.TreePath path = get_path(iter);
      
    if (added)
      row_inserted(path, iter);
    else
      row_changed(path, iter);
  }
    
  public Type get_column_type (int index) {
    switch(index) {
    case 0:
      return typeof(Contact);
    }
    
    return Type.INVALID;
  }
    
  public Gtk.TreeModelFlags get_flags () {
    return Gtk.TreeModelFlags.LIST_ONLY;
  }
    
  public bool get_iter (out Gtk.TreeIter iter, Gtk.TreePath path) {
    if(path.get_depth() != 1)
      return false;
      
    int index = path.get_indices()[0];
    if(index < 0 || index >= entries.size)
      return false;
      
    Gee.MapIterator<string, Contact> it = entries.map_iterator();
    it.first();
    for(int i = 0; i < index; ++i)
      it.next();
      
    iter.stamp = stamp;
    iter.user_data = this;
    iter.user_data2 = it.get_value();
      
    return true;
  }
  
  public int get_n_columns () {
    return 1;
  }
  
  public Gtk.TreePath get_path (Gtk.TreeIter iter) {
    if(iter.stamp != stamp || iter.user_data != this)
      return (Gtk.TreePath)null;
      
    int index = 0;
      
    foreach(Contact c in entries.values) {
      if(c == iter.user_data2)
        break;
        
      ++index;
    }
      
    return new Gtk.TreePath.from_indices(index, -1);
  }
    
  public void get_value (Gtk.TreeIter iter, int column, out Value value) {
    if (column != 0 || iter.stamp != stamp || iter.user_data != this)
      return;
      
    Contact c = iter.user_data2 as Contact;
    value = Value(typeof(Contact));
    value.take_object(c);
  }
    
  public bool iter_children (out Gtk.TreeIter iter, Gtk.TreeIter? parent) {
    if (parent != null) {
      iter.stamp = -1;
      return false;
    }
      
    return get_iter(out iter, new Gtk.TreePath.from_indices(0, -1));
  }
    
  public bool iter_has_child (Gtk.TreeIter iter) {
    return false;
  }
    
  public int iter_n_children (Gtk.TreeIter? iter) {
    if (iter == null)
      return entries.size;
    else
      return 0;
  }
    
  public bool iter_next (ref Gtk.TreeIter iter) {
    if(iter.stamp != stamp || iter.user_data != this)
      return false;
      
    bool next = false;
    foreach(Contact c in entries.values) {
      if(next) {
        iter.user_data2 = c;
        return true;
      }
        
      if(c == iter.user_data2)
        next = true;
    }
      
    iter.stamp = -1;
    return false;
  }
    
  public bool iter_nth_child (out Gtk.TreeIter iter, Gtk.TreeIter? parent, int n) {
    if (parent != null) {
      iter.stamp = -1;
      return false;
    }
      
    return get_iter(out iter, new Gtk.TreePath.from_indices(n, -1));
  }
    
  public bool iter_parent (out Gtk.TreeIter iter, Gtk.TreeIter child) {
    iter.stamp = -1;
    return false;
  }
    
  public void ref_node (Gtk.TreeIter iter) {}
  public void unref_node (Gtk.TreeIter iter) {}
}