/* tomboykeybinder.c
 * Copyright (C) 2008 Novell
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110, USA 
 */
#include <string.h>

#include <gdk/gdk.h>
#include <gdk/gdkwindow.h>
#include <gdk/gdkx.h>
#include <X11/Xlib.h>

#include "eggaccelerators.h"
#include "tomboykeybinder.h"

/* Uncomment the next line to print a debug trace. */
/* #define DEBUG */

#ifdef DEBUG
#  define TRACE(x) x
#else
#  define TRACE(x) do {} while (FALSE);
#endif

typedef struct _Binding {
	TomboyBindkeyHandler  handler;
	gpointer              user_data;
	char                 *keystring;
	uint                  keycode;
	uint                  modifiers;
} Binding;

static GSList *bindings = NULL;
static guint32 last_event_time = 0;
static gboolean processing_event = FALSE;

static guint num_lock_mask, caps_lock_mask, scroll_lock_mask;

static void
lookup_ignorable_modifiers (GdkKeymap *keymap)
{
	egg_keymap_resolve_virtual_modifiers (keymap, 
					      EGG_VIRTUAL_LOCK_MASK,
					      &caps_lock_mask);

	egg_keymap_resolve_virtual_modifiers (keymap, 
					      EGG_VIRTUAL_NUM_LOCK_MASK,
					      &num_lock_mask);

	egg_keymap_resolve_virtual_modifiers (keymap, 
					      EGG_VIRTUAL_SCROLL_LOCK_MASK,
					      &scroll_lock_mask);
}

static void
grab_ungrab_with_ignorable_modifiers (GdkWindow *rootwin, 
				      Binding   *binding,
				      gboolean   grab)
{
	guint mod_masks [] = {
		0, /* modifier only */
		num_lock_mask,
		caps_lock_mask,
		scroll_lock_mask,
		num_lock_mask  | caps_lock_mask,
		num_lock_mask  | scroll_lock_mask,
		caps_lock_mask | scroll_lock_mask,
		num_lock_mask  | caps_lock_mask | scroll_lock_mask,
	};
	guint i;

	for (i = 0; i < G_N_ELEMENTS (mod_masks); i++) {
		if (grab) {
			XGrabKey (GDK_WINDOW_XDISPLAY (rootwin), 
				  binding->keycode, 
				  binding->modifiers | mod_masks [i], 
				  GDK_WINDOW_XWINDOW (rootwin), 
				  False, 
				  GrabModeAsync,
				  GrabModeAsync);
		} else {
			XUngrabKey (GDK_WINDOW_XDISPLAY (rootwin),
				    binding->keycode,
				    binding->modifiers | mod_masks [i], 
				    GDK_WINDOW_XWINDOW (rootwin));
		}
	}
}

static gboolean 
do_grab_key (Binding *binding)
{
	GdkKeymap *keymap = gdk_keymap_get_default ();
	GdkWindow *rootwin = gdk_get_default_root_window ();

	EggVirtualModifierType virtual_mods = 0;
	guint keysym = 0;

	if (keymap == NULL || rootwin == NULL)
		return FALSE;

	if (!egg_accelerator_parse_virtual (binding->keystring, 
					    &keysym, 
					    &virtual_mods))
		return FALSE;

	TRACE (g_print ("Got accel %d, %d\n", keysym, virtual_mods));

	binding->keycode = XKeysymToKeycode (GDK_WINDOW_XDISPLAY (rootwin), 
					     keysym);
	if (binding->keycode == 0)
		return FALSE;

	TRACE (g_print ("Got keycode %d\n", binding->keycode));

	egg_keymap_resolve_virtual_modifiers (keymap,
					      virtual_mods,
					      &binding->modifiers);
	if (binding->modifiers == 0)
		return FALSE;

	TRACE (g_print ("Got modmask %d\n", binding->modifiers));

	gdk_error_trap_push ();

	grab_ungrab_with_ignorable_modifiers (rootwin, 
					      binding, 
					      TRUE /* grab */);

	gdk_flush ();

	if (gdk_error_trap_pop ()) {
	   g_warning ("Binding '%s' failed!\n", binding->keystring);
	   return FALSE;
	}

	return TRUE;
}

static gboolean 
do_ungrab_key (Binding *binding)
{
	GdkWindow *rootwin = gdk_get_default_root_window ();

	TRACE (g_print ("Removing grab for '%s'\n", binding->keystring));

	grab_ungrab_with_ignorable_modifiers (rootwin, 
					      binding, 
					      FALSE /* ungrab */);

	return TRUE;
}

static GdkFilterReturn
filter_func (GdkXEvent *gdk_xevent, GdkEvent *event G_GNUC_UNUSED,
             gpointer data G_GNUC_UNUSED)
{
	GdkFilterReturn return_val = GDK_FILTER_CONTINUE;
	XEvent *xevent = (XEvent *) gdk_xevent;
	guint event_mods;
	GSList *iter;

	TRACE (g_print ("Got Event! %d, %d\n", xevent->type, event->type));

	switch (xevent->type) {
	case KeyPress:
		TRACE (g_print ("Got KeyPress! keycode: %d, modifiers: %d\n", 
				xevent->xkey.keycode, 
				xevent->xkey.state));

		/* 
		 * Set the last event time for use when showing
		 * windows to avoid anti-focus-stealing code.
		 */
		processing_event = TRUE;
		last_event_time = xevent->xkey.time;

		event_mods = xevent->xkey.state & ~(num_lock_mask  | 
						    caps_lock_mask | 
						    scroll_lock_mask);

		for (iter = bindings; iter != NULL; iter = iter->next) {
			Binding *binding = (Binding *) iter->data;
						       
			if (binding->keycode == xevent->xkey.keycode &&
			    binding->modifiers == event_mods) {

				TRACE (g_print ("Calling handler for '%s'...\n", 
						binding->keystring));

				(binding->handler) (binding->keystring, 
						    binding->user_data);
			}
		}

		processing_event = FALSE;
		break;
	case KeyRelease:
		TRACE (g_print ("Got KeyRelease! \n"));
		break;
	}

	return return_val;
}

static void 
keymap_changed (GdkKeymap *map G_GNUC_UNUSED)
{
	GdkKeymap *keymap = gdk_keymap_get_default ();
	GSList *iter;

	TRACE (g_print ("Keymap changed! Regrabbing keys..."));

	for (iter = bindings; iter != NULL; iter = iter->next) {
		Binding *binding = (Binding *) iter->data;
		do_ungrab_key (binding);
	}

	lookup_ignorable_modifiers (keymap);

	for (iter = bindings; iter != NULL; iter = iter->next) {
		Binding *binding = (Binding *) iter->data;
		do_grab_key (binding);
	}
}

void 
tomboy_keybinder_init (void)
{
	GdkKeymap *keymap = gdk_keymap_get_default ();
	GdkWindow *rootwin = gdk_get_default_root_window ();

	lookup_ignorable_modifiers (keymap);

	gdk_window_add_filter (rootwin, 
			       filter_func, 
			       NULL);

	g_signal_connect (keymap, 
			  "keys_changed",
			  G_CALLBACK (keymap_changed),
			  NULL);
}

void 
tomboy_keybinder_bind (const char           *keystring,
		       TomboyBindkeyHandler  handler,
		       gpointer              user_data)
{
	Binding *binding;
	gboolean success;

	binding = g_new0 (Binding, 1);
	binding->keystring = g_strdup (keystring);
	binding->handler = handler;
	binding->user_data = user_data;

	/* Sets the binding's keycode and modifiers */
	success = do_grab_key (binding);

	if (success) {
		bindings = g_slist_prepend (bindings, binding);
	} else {
		g_free (binding->keystring);
		g_free (binding);
	}
}

void
tomboy_keybinder_unbind (const char           *keystring, 
			 TomboyBindkeyHandler  handler)
{
	GSList *iter;

	for (iter = bindings; iter != NULL; iter = iter->next) {
		Binding *binding = (Binding *) iter->data;

		if (strcmp (keystring, binding->keystring) != 0 ||
		    handler != binding->handler) 
			continue;

		do_ungrab_key (binding);

		bindings = g_slist_remove (bindings, binding);

		g_free (binding->keystring);
		g_free (binding);
		break;
	}
}

/* 
 * From eggcellrenderkeys.c.
 */
gboolean
tomboy_keybinder_is_modifier (guint keycode)
{
	gint i;
	gint map_size;
	XModifierKeymap *mod_keymap;
	gboolean retval = FALSE;

	mod_keymap = XGetModifierMapping (gdk_display);

	map_size = 8 * mod_keymap->max_keypermod;

	i = 0;
	while (i < map_size) {
		if (keycode == mod_keymap->modifiermap[i]) {
			retval = TRUE;
			break;
		}
		++i;
	}

	XFreeModifiermap (mod_keymap);

	return retval;
}

guint32
tomboy_keybinder_get_current_event_time (void)
{
	if (processing_event) 
		return last_event_time;
	else
		return GDK_CURRENT_TIME;
}
