#include <gtk/gtk.h>

typedef struct 
{
  gchar *str;
  double scale;
} text_to_double;

const text_to_double text_scales[] = 
{
  { "Quarter Sized", (double) 0.25 },
  { "Double Extra Small", PANGO_SCALE_XX_SMALL},
  { "Extra Small", PANGO_SCALE_X_SMALL},
  { "Small", PANGO_SCALE_SMALL },
  { "Medium", PANGO_SCALE_MEDIUM },
  { "Large", PANGO_SCALE_LARGE},
  { "Extra Large", PANGO_SCALE_X_LARGE},
  { "Double Extra Large", PANGO_SCALE_XX_LARGE},
  { "Double Sized", (double) 2.0 },
  { NULL, 0 } 
};

static void format (GtkWidget*, GtkTextView*);
static void scale_changed (GtkComboBox*, GtkTextView*);
static void clear_clicked (GtkButton*, GtkTextView*);

int main (int argc,
          char *argv[])
{
  GtkWidget *window, *scrolled_win, *textview, *hbox, *vbox;
  GtkWidget *bold, *italic, *underline, *strike, *scale, *clear;
  GtkTextBuffer *buffer;
  gint i = 0;
  
  gtk_init (&argc, &argv);
  
  window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
  gtk_window_set_title (GTK_WINDOW (window), "Text Tags");
  gtk_container_set_border_width (GTK_CONTAINER (window), 10);
  gtk_widget_set_size_request (window, 500, -1);
  
  g_signal_connect (G_OBJECT (window), "destroy",
                    G_CALLBACK (gtk_main_quit), NULL);
  
  textview = gtk_text_view_new ();
  buffer = gtk_text_view_get_buffer (GTK_TEXT_VIEW (textview));

  gtk_text_buffer_create_tag (buffer, "bold", "weight", PANGO_WEIGHT_BOLD, NULL);
  gtk_text_buffer_create_tag (buffer, "italic", "style", PANGO_STYLE_ITALIC, NULL);
  gtk_text_buffer_create_tag (buffer, "strike", "strikethrough", TRUE, NULL);
  gtk_text_buffer_create_tag (buffer, "underline", "underline", 
                              PANGO_UNDERLINE_SINGLE, NULL);

  bold = gtk_button_new_from_stock (GTK_STOCK_BOLD);
  italic = gtk_button_new_from_stock (GTK_STOCK_ITALIC);
  underline = gtk_button_new_from_stock (GTK_STOCK_UNDERLINE);
  strike = gtk_button_new_from_stock (GTK_STOCK_STRIKETHROUGH);
  clear = gtk_button_new_from_stock (GTK_STOCK_CLEAR);
  scale = gtk_combo_box_new_text();

  /* Add choices to the GtkComboBox widget. */
  for (i = 0; text_scales[i].str != NULL; i++) 
  {
    gtk_combo_box_append_text (GTK_COMBO_BOX (scale), text_scales[i].str);
    gtk_text_buffer_create_tag (buffer, text_scales[i].str, "scale", 
                                text_scales[i].scale, NULL );
  }
  
  /* Add the name of the text tag as a data parameter of the object. */
  g_object_set_data (G_OBJECT (bold), "tag", "bold");
  g_object_set_data (G_OBJECT (italic), "tag", "italic");
  g_object_set_data (G_OBJECT (underline), "tag", "underline");
  g_object_set_data (G_OBJECT (strike), "tag", "strike");

  /* Connect each of the buttons and the combo box to the necessary signals. */
  g_signal_connect (G_OBJECT (bold), "clicked",
                    G_CALLBACK (format), (gpointer) textview);
  g_signal_connect (G_OBJECT (italic), "clicked",
                    G_CALLBACK (format), (gpointer) textview);
  g_signal_connect (G_OBJECT (underline), "clicked",
                    G_CALLBACK (format), (gpointer) textview);
  g_signal_connect (G_OBJECT (strike), "clicked",
                    G_CALLBACK (format), (gpointer) textview);
  g_signal_connect (G_OBJECT (scale), "changed",
                    G_CALLBACK (scale_changed),
                    (gpointer) textview);
  g_signal_connect (G_OBJECT (clear), "clicked",
                    G_CALLBACK (clear_clicked),
                    (gpointer) textview);

  /* Pack the widgets into a GtkVBox, GtkHBox, and then into the window. */
  vbox = gtk_vbox_new (TRUE, 5);
  gtk_box_pack_start (GTK_BOX (vbox), bold, FALSE, FALSE, 0);
  gtk_box_pack_start (GTK_BOX (vbox), italic, FALSE, FALSE, 0);
  gtk_box_pack_start (GTK_BOX (vbox), underline, FALSE, FALSE, 0);
  gtk_box_pack_start (GTK_BOX (vbox), strike, FALSE, FALSE, 0);
  gtk_box_pack_start (GTK_BOX (vbox), scale, FALSE, FALSE, 0);
  gtk_box_pack_start (GTK_BOX (vbox), clear, FALSE, FALSE, 0);
  
  scrolled_win = gtk_scrolled_window_new (NULL, NULL);
  gtk_container_add (GTK_CONTAINER (scrolled_win), textview);
  gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (scrolled_win),
                                  GTK_POLICY_AUTOMATIC, GTK_POLICY_ALWAYS);

  hbox = gtk_hbox_new (FALSE, 5);
  gtk_box_pack_start (GTK_BOX (hbox), scrolled_win, TRUE, TRUE, 0);
  gtk_box_pack_start (GTK_BOX (hbox), vbox, FALSE, TRUE, 0);
  
  gtk_container_add (GTK_CONTAINER (window), hbox);
  gtk_widget_show_all (window);
  
  gtk_main();
  return 0;
}

/* Retrieve the tag from the "tag" object data and apply it to the selection. */
static void
format (GtkWidget *widget,
        GtkTextView *textview)
{
  GtkTextIter start, end;
  GtkTextBuffer *buffer;
  gchar *tagname;

  tagname = (gchar*) g_object_get_data (G_OBJECT (widget), "tag");
  buffer = gtk_text_view_get_buffer (textview);
  gtk_text_buffer_get_selection_bounds (buffer, &start, &end);
  gtk_text_buffer_apply_tag_by_name (buffer, tagname, &start, &end);
}

/* Apply the selected text size property as the tag. */
static void
scale_changed (GtkComboBox *combo,
               GtkTextView *textview)
{
  const gchar *text;

  if (gtk_combo_box_get_active (combo) == -1)
    return;

  text = gtk_combo_box_get_active_text (combo);
  g_object_set_data (G_OBJECT (combo), "tag", (gpointer) text);
  format (GTK_WIDGET (combo), textview);
  gtk_combo_box_set_active (combo, -1);
}

/* Remove all of the tags from the selected text. */
static void
clear_clicked (GtkButton *button,
               GtkTextView *textview)
{
  GtkTextIter start, end;
  GtkTextBuffer *buffer;

  buffer = gtk_text_view_get_buffer (textview);
  gtk_text_buffer_get_selection_bounds (buffer, &start, &end);
  gtk_text_buffer_remove_all_tags (buffer, &start, &end);
}