#include <gtk-3.0/gtk/gtk.h>

GtkWidget *window;
GtkWidget *image;
GdkPixbuf *pixbuf;
GdkPixbuf *curr_pixbuf;
int pixbuf_width, pixbuf_height;
double aspect_ratio;

static gboolean key_press(GtkWindow *window, gpointer data)
{
	GdkEventKey *event = (GdkEventKey *)data;
	if (event->keyval == GDK_KEY_q) {
		g_application_quit(G_APPLICATION(
		    gtk_window_get_application(GTK_WINDOW(window))));
		return FALSE;
	} else
		return TRUE;
}

void configure_callback(GtkWindow *window, GdkEvent *event, gpointer data)
{
	gint win_width, win_height;
	gint new_pixbuf_width, new_pixbuf_height;
	gtk_window_get_size(GTK_WINDOW(window), &win_width, &win_height);

	if (win_width < pixbuf_width && win_height > pixbuf_height) {
		new_pixbuf_width = win_width;
		new_pixbuf_height = (double)new_pixbuf_width / aspect_ratio;
	} else if (win_width > pixbuf_width && win_height < pixbuf_height) {
		new_pixbuf_height = win_height;
		new_pixbuf_width = (double)new_pixbuf_height * aspect_ratio;
	} else if (win_width < pixbuf_width && win_height < pixbuf_height) {
		if (((double)win_width / (double)win_height) > aspect_ratio) {
			new_pixbuf_height = win_height;
			new_pixbuf_width =
			    ((double)new_pixbuf_height * aspect_ratio);
		} else {
			new_pixbuf_width = win_width;
			new_pixbuf_height =
			    (double)new_pixbuf_width / aspect_ratio;
		}
	} else {
		new_pixbuf_width = pixbuf_width;
		new_pixbuf_height = pixbuf_height;
	}

	gtk_container_remove(GTK_CONTAINER(window), GTK_WIDGET(image));
	if (curr_pixbuf != NULL)
		g_object_unref(curr_pixbuf);
	curr_pixbuf =
	    gdk_pixbuf_scale_simple(GDK_PIXBUF(pixbuf), new_pixbuf_width,
				    new_pixbuf_height, GDK_INTERP_BILINEAR);
	image = gtk_image_new_from_pixbuf(GDK_PIXBUF(curr_pixbuf));
	gtk_container_add(GTK_CONTAINER(window), GTK_WIDGET(image));
	gtk_widget_show_all(GTK_WIDGET(window));
}

static void activate(GtkApplication *app, gpointer user_data)
{
	GError *error = NULL;

	window = gtk_application_window_new(app);
	g_signal_connect(G_OBJECT(window), "configure-event",
			 G_CALLBACK(configure_callback), NULL);
	g_signal_connect(G_OBJECT(window), "key-press-event",
			 G_CALLBACK(key_press), NULL);

	gtk_window_set_title(GTK_WINDOW(window), "qwe");
	gtk_window_set_default_size(GTK_WINDOW(window), 300, 300);
	pixbuf = gdk_pixbuf_new_from_file(
	    "/home/nirav/Downloads/Saved Pictures/bash help shortcuts.png",
	    &error);
	if (error) {
		g_warning("gdk_pixbuf_new_from_file() failed with error: %s\n",
			  error->message);
		g_clear_error(&error);
		return;
	}

	image = gtk_image_new_from_pixbuf(GDK_PIXBUF(pixbuf));
	pixbuf_width = gdk_pixbuf_get_width(GDK_PIXBUF(pixbuf));
	pixbuf_height = gdk_pixbuf_get_height(GDK_PIXBUF(pixbuf));
	aspect_ratio = (double)pixbuf_width / (double)pixbuf_height;

	gtk_container_add(GTK_CONTAINER(window), GTK_WIDGET(image));
	gtk_widget_show_all(GTK_WIDGET(window));
}

int main(int argc, char *argv[])
{
	GtkApplication *app;
	int status;
	app = gtk_application_new("org.gtk.qwe", G_APPLICATION_FLAGS_NONE);
	g_signal_connect(app, "activate", G_CALLBACK(activate), NULL);
	status = g_application_run(G_APPLICATION(app), argc, argv);
	g_object_unref(app);
	return status;
}