#include <gtk/gtk.h>
#include <gtksourceview/gtksource.h>
#include <gdk/gdkkeysyms.h>
#include <glib/gi18n.h>
#include <errno.h>

void dialog_show(GtkWidget *textview);

int main (int argc,
char *argv[])
{
	GtkWidget *window, *scrolled_win, *textview;
	GtkWidget *vbox, *menubar, *fileMenu, *fileMi, *quit_item, *open_item;

	gtk_init (&argc, &argv);

	window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
	gtk_window_maximize(GTK_WINDOW (window)); /* This is a cast: expand the windows to fullscreen*/
	vbox = gtk_box_new(GTK_ORIENTATION_VERTICAL, 12);
	gtk_container_add(GTK_CONTAINER(window), vbox);

	gtk_window_set_title (GTK_WINDOW (window), "Text Views");
	gtk_container_set_border_width (GTK_CONTAINER (window), 10);

	textview = gtk_source_view_new();

	menubar = gtk_menu_bar_new();
	fileMenu = gtk_menu_new();

	fileMi = gtk_menu_item_new_with_label("File");

	open_item = gtk_menu_item_new_with_label("Open");
	quit_item = gtk_menu_item_new_with_label("Quit");

	/* CTRL-Q accelerator */
	GtkAccelGroup *accel_group = NULL;
    accel_group = gtk_accel_group_new();
    gtk_window_add_accel_group(GTK_WINDOW(window), accel_group);

	gtk_widget_add_accelerator(quit_item, "activate", accel_group,
      GDK_KEY_q, GDK_CONTROL_MASK, GTK_ACCEL_VISIBLE);

	/*Expand the textbox to fullscreen */
	gtk_widget_set_hexpand(textview, TRUE);
	gtk_widget_set_vexpand(textview, TRUE);

	GtkCssProvider *provider = gtk_css_provider_new ();
	gtk_css_provider_load_from_path (provider,
    "gtk-widgets.css", NULL);

    GtkStyleContext *context;

    context = gtk_widget_get_style_context(textview);

	gtk_style_context_add_provider (context,
                                    GTK_STYLE_PROVIDER(provider),
                                    GTK_STYLE_PROVIDER_PRIORITY_USER);

	gtk_menu_item_set_submenu(GTK_MENU_ITEM(fileMi), fileMenu);
	gtk_menu_shell_append(GTK_MENU_SHELL(fileMenu), open_item);
  	gtk_menu_shell_append(GTK_MENU_SHELL(fileMenu), quit_item);

	gtk_menu_shell_append(GTK_MENU_SHELL(menubar), fileMi);
	gtk_box_pack_start(GTK_BOX(vbox), menubar, FALSE, FALSE, 0);

	scrolled_win = gtk_scrolled_window_new (NULL, NULL);
	gtk_container_add(GTK_CONTAINER(vbox), scrolled_win);
	gtk_container_add (GTK_CONTAINER (scrolled_win), textview);

	gtk_source_view_set_show_line_numbers (GTK_SOURCE_VIEW(textview), TRUE); /*Show line numbers */

	gtk_widget_show_all (window);

	g_signal_connect(G_OBJECT(window), "destroy",
        G_CALLBACK(gtk_main_quit), NULL);

    g_signal_connect(G_OBJECT(quit_item), "activate",
        G_CALLBACK(gtk_main_quit), NULL);

    g_signal_connect(G_OBJECT(open_item), "activate",
        G_CALLBACK(dialog_show), &textview);

	gtk_main();

	return 0;
}

void dialog_show(GtkWidget *textview)
{
	FILE *fp;

	GtkWindow *parent_window = NULL;

	GtkFileChooserNative *native;
	gint res;

	native = gtk_file_chooser_native_new ("Open File",
                                      parent_window,
                                      GTK_FILE_CHOOSER_ACTION_OPEN,
                                       _("_Open"),
                                       _("_Cancel"));

	res = gtk_native_dialog_run (GTK_NATIVE_DIALOG (native));

	if (res == GTK_RESPONSE_ACCEPT)
	  {
		char *filename;
		GtkFileChooser *chooser = GTK_FILE_CHOOSER (native);
		filename = gtk_file_chooser_get_filename (chooser);

		if(!(fp = fopen(filename, "r"))) /* if file cannot be opened */
		{
			g_printerr("%s: %s\n", filename, g_strerror(errno));
			return;
		}

		else {
		    char *buf;
		    GtkTextBuffer * buffer = gtk_text_view_get_buffer (textview);
		    fseek(fp, 0, SEEK_END);
		    long fsize = ftell(fp);
		    fseek(fp, 0, SEEK_SET);

		    buf = malloc(fsize + 1);
		    fread(buf, fsize, 1, fp);
		    buf[fsize] = '\0';

		    gtk_text_buffer_set_text(buffer, buf, -1);

		    free(buf);
			fclose(fp);
		}

		g_free (filename);
		fclose(fp);
	  }

	g_object_unref (native);

}