#include <gdk/gdkkeysyms.h>
#include <gtk/gtk.h>
#include <cairo.h>
#include <math.h>
#include <librsvg/rsvg.h>
#include <librsvg/rsvg-cairo.h>

#define SECOND_INTERVAL  1000

#define DEFAULT_WIDTH  200
#define DEFAULT_HEIGHT 100


typedef struct
{
  gboolean active;   /* whether the selection is active or not */
  gdouble  x, y;
} selection_t;



gboolean on_key_press (GtkWidget *widget, 
		       GdkEventKey *key, 
		       gpointer p) {
	if (key->type == GDK_KEY_PRESS)
	{
		switch (key->keyval)
		{
			case GDK_Escape :
				gtk_main_quit ();
			break;
		}
	}

	return FALSE;
}

gboolean on_mouse_press (GtkWidget      *widget,
			 GdkEventButton *bev,
			 selection_t    *sel) {	
	sel->active = TRUE;

	sel->x = bev->x;	
	sel->y = bev->y;

	gtk_widget_queue_draw (widget);
	
	return TRUE;
}

gboolean on_mouse_release (GtkWidget      *widget,
			   GdkEventButton *bev,
			   selection_t    *sel) {

	sel->active = FALSE;

	sel->x = 0;
	sel->y = 0;
	
	gtk_widget_queue_draw (widget);

	return TRUE;
}

gboolean on_mouse_motion (GtkWidget      *widget,
			  GdkEventButton *bev,
			  selection_t    *sel) {
	sel->x = bev->x;
	sel->y = bev->y;

	gtk_widget_queue_draw (widget);

	return TRUE;
}

static void paint_dot (cairo_t *cr, selection_t *sel) {
	if (!sel->active)
		return;

	cairo_save (cr);
	  cairo_arc (cr, sel->x, sel->y, 30., 0., 2 * M_PI);
	  cairo_set_source_rgba (cr, 0, 0, 0, 0.2);
	  cairo_fill_preserve (cr);
	  
	  cairo_set_source_rgba (cr, 0, 0, 0, 0.5);
	  cairo_stroke (cr);	      
        cairo_restore (cr);

}

static void paint (GtkWidget *widget, GdkEventExpose *eev, selection_t *sel) {
	gint width, height, cache;
	cairo_t *cr;
	gint i;
	gchar d[2] = {'0','\0'};
	gfloat colors[6][3] = {{0.0f, 0.0f, 1.0f},	
			       {0.0f, 1.0f, 0.0f},
			       {1.0f, 0.0f, 0.0f},
			       {1.0f, 1.0f, 0.0f},
			       {1.0f, 0.0f, 1.0f},
			       {0.0f, 1.0f, 1.1f}};
	
	width  = widget->allocation.width;
	height = widget->allocation.height;

	cr = gdk_cairo_create (widget->window);
	cairo_set_operator (cr, CAIRO_OPERATOR_SOURCE);	

	cairo_set_source_rgba (cr, 1.0f, 1.0f, 1.0f, 0.4f);	

	cairo_paint (cr);

	cairo_select_font_face (cr, "Sans", CAIRO_FONT_SLANT_NORMAL,
				            CAIRO_FONT_WEIGHT_BOLD);

	for (i = 0; i < 6; i++) {
		cairo_save (cr);
  		  cairo_set_font_size (cr, 10);
		  cairo_set_source_rgba (cr, colors[i][0],
					     colors[i][1],
				             colors[i][2],
					 1.0f);
		  cairo_move_to (cr, 10*i, 10);
		  d[0] = '0' + i;
		  cairo_show_text (cr, d);
		cairo_restore (cr);
	}
	

	cairo_save (cr);
	cairo_set_source_rgba (cr, 1.0f, 1.0f, 0.0f, 1.0f);       
	cairo_move_to (cr, 10, 20);
	cairo_translate (cr, width/2, height/2);


	for ( i = 0; i < 4; i++ ) {		
		cairo_translate (cr, -width/2, -height/2);

		cairo_curve_to (cr,  10, 20, 10, 10, 20, 10);
		cairo_line_to  (cr,  width - 20, 10);
		
		cairo_translate (cr, width/2, height/2);
		cairo_rotate (cr, M_PI/2.0);
		cache = width; width = height; height = cache;
	}

	cairo_fill_preserve (cr);
	cairo_set_source_rgba (cr, 0.0f, 1.0f, 0.0f, 0.4f);
	cairo_stroke (cr);	
	cairo_restore (cr);

	paint_dot (cr, sel);
	
	cairo_destroy (cr);
}

static void install_colormap (GtkWidget *w) {
	GdkScreen* screen     = gtk_widget_get_screen (w);
	GdkColormap* colormap = gdk_screen_get_rgba_colormap (screen);

	if (!colormap)
		colormap = gdk_screen_get_rgb_colormap (screen);

	gtk_widget_set_colormap (w, colormap);
}	       
	
gint main (gint argc, gchar **argv) { 
	GtkWidget *window;
	selection_t sel = {FALSE, 0, 0,};

	gtk_init(&argc, &argv);
	
	window = gtk_window_new (GTK_WINDOW_TOPLEVEL);

	gtk_window_stick (GTK_WINDOW (window));
	//	gtk_window_set_keep_below (GTK_WINDOW (window), TRUE);

        gtk_window_set_skip_taskbar_hint (GTK_WINDOW (window), TRUE);
	gtk_window_set_skip_pager_hint   (GTK_WINDOW (window), TRUE);
	// gtk_window_set_accept_focus      (GTK_WINDOW (window), FALSE);

	gtk_window_set_decorated (GTK_WINDOW (window), TRUE);
	gtk_window_set_resizable (GTK_WINDOW (window), TRUE);
	gtk_widget_set_app_paintable (window, TRUE);
	
	gtk_window_set_default_size (GTK_WINDOW (window),
				     DEFAULT_WIDTH,
				     DEFAULT_HEIGHT);

	install_colormap(window);
	
	gtk_widget_add_events (window, GDK_BUTTON_PRESS_MASK  | 
			               GDK_BUTTON_MOTION_MASK |
			               GDK_BUTTON_RELEASE_MASK);

	g_signal_connect (G_OBJECT (window), "expose-event",
			  G_CALLBACK (paint),
			  &sel);
	
	g_signal_connect (G_OBJECT (window),
			  "key-press-event",
			  G_CALLBACK (on_key_press),
			  NULL);

	/* connect our rubber banding callbacks, like the paint callback
	 * we pass the selection as userdata
	 */
	g_signal_connect (G_OBJECT (window), "button_press_event",
			  G_CALLBACK (on_mouse_press),
			  &sel);

	g_signal_connect (G_OBJECT (window), "button_release_event",
			  G_CALLBACK (on_mouse_release),
			  &sel);

	g_signal_connect (G_OBJECT (window), "motion_notify_event",
			  G_CALLBACK (on_mouse_motion),
			  &sel);

	gtk_widget_show_all (window);

	gtk_main ();

	return 0;
}