/* 
 * Compile with:
 *  gcc -o tree-swap tree-swap.c `pkg-config --cflags --libs gtk+-2.0`
 *
 */

#include <gtk/gtk.h>

enum
{
  COL_NAME = 0,
  NUM_COLS
} ;


static GtkTreeModel *
create_and_fill_model (void)
{
  GtkTreeStore  *store;
  GtkTreeIter    a, b, c, x;
  
  store = gtk_tree_store_new (NUM_COLS, G_TYPE_STRING);

  gtk_tree_store_append (store, &a, NULL);
  gtk_tree_store_set (store, &a, COL_NAME, "a", -1);
  
  gtk_tree_store_append (store, &b, NULL);
  gtk_tree_store_set (store, &b, COL_NAME, "b", -1);
  
  gtk_tree_store_append (store, &c, NULL);
  gtk_tree_store_set (store, &c, COL_NAME, "c", -1);
  
  gtk_tree_store_append (store, &x, &c);
  gtk_tree_store_set (store, &x, COL_NAME, "1", -1);
  
  gtk_tree_store_append (store, &x, &c);
  gtk_tree_store_set (store, &x, COL_NAME, "2", -1);
  
  gtk_tree_store_append (store, &x, &c);
  gtk_tree_store_set (store, &x, COL_NAME, "3", -1);
  
  return GTK_TREE_MODEL (store);
}

static GtkWidget *
create_view_and_model (void)
{
  GtkTreeViewColumn   *col;
  GtkCellRenderer     *renderer;
  GtkTreeModel        *model;
  GtkWidget           *view;

  view = gtk_tree_view_new ();

  renderer = gtk_cell_renderer_text_new ();
  gtk_tree_view_insert_column_with_attributes (GTK_TREE_VIEW (view),
                                               -1,      
                                               "Name",  
                                               renderer,
                                               "text", COL_NAME,
                                               NULL);

  model = create_and_fill_model ();

  gtk_tree_view_set_model (GTK_TREE_VIEW (view), model);

  g_object_unref (model); /* destroy model automatically with view */

  return view;
}

static void
move_up (GtkButton *button, gpointer data)
{
  GtkTreeView *tree = GTK_TREE_VIEW (data);
  GtkTreeModel *model;
  GtkTreeSelection *sel;
  GtkTreePath *path;
  GtkTreeIter a, b;

  sel = gtk_tree_view_get_selection (tree);
  if (gtk_tree_selection_get_selected (sel, NULL, &a)) {
    model = gtk_tree_view_get_model (tree);
    path = gtk_tree_model_get_path (model, &a);
    gtk_tree_path_prev (path);
    gtk_tree_model_get_iter (model, &b, path);
    gtk_tree_store_swap (GTK_TREE_STORE (model), &a, &b);
  }
}

static void
move_down (GtkButton *button, gpointer data)
{
  GtkTreeView *tree = GTK_TREE_VIEW (data);
  GtkTreeModel *model;
  GtkTreeSelection *sel;
  GtkTreeIter a, b;

  sel = gtk_tree_view_get_selection (tree);
  if (gtk_tree_selection_get_selected (sel, NULL, &a)) {
    b = a;
    model = gtk_tree_view_get_model (tree);
    gtk_tree_model_iter_next (model, &b);
    gtk_tree_store_swap (GTK_TREE_STORE (model), &a, &b);
  }
}

int
main (int argc, char **argv)
{
  GtkWidget *window, *view, *vbox, *button;

  gtk_init (&argc, &argv);

  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
  g_signal_connect (window, "delete_event", gtk_main_quit, NULL); /* dirty */

  view = create_view_and_model ();

  vbox = gtk_vbox_new (FALSE, 5);
  gtk_box_pack_start (GTK_BOX (vbox), view, TRUE, TRUE, 0);

  button = gtk_button_new_with_label ("Move up");
  g_signal_connect (button, "clicked", (GCallback)move_up, (gpointer) view);
  gtk_box_pack_start (GTK_BOX (vbox), button, TRUE, TRUE, 0);

  button = gtk_button_new_with_label ("Move down");
  g_signal_connect (button, "clicked", (GCallback)move_down, (gpointer) view);
  gtk_box_pack_start (GTK_BOX (vbox), button, TRUE, TRUE, 0);

  gtk_container_add (GTK_CONTAINER (window), vbox);
  gtk_widget_show_all (window);
  gtk_tree_view_expand_all (GTK_TREE_VIEW (view));

  gtk_main ();

  return 0;
}