/*
 * Copyright 2011 kubtek <kubtek@mail.com>
 *
 * This file is part of StarDict.
 *
 * StarDict is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * StarDict 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with StarDict.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <string.h>

#include <gdk/gdk.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;
	GdkModifierType       modifiers;
} Binding;

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

static GdkModifierType 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,
		(guint)(num_lock_mask  | caps_lock_mask),
		(guint)(num_lock_mask  | scroll_lock_mask),
		(guint)(caps_lock_mask | scroll_lock_mask),
		(guint)(num_lock_mask  | caps_lock_mask | scroll_lock_mask),
	};
	size_t 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_XID (rootwin),
				  False,
				  GrabModeAsync,
				  GrabModeAsync);
		} else {
			XUngrabKey (GDK_WINDOW_XDISPLAY (rootwin),
				    binding->keycode,
				    binding->modifiers | mod_masks [i],
				    GDK_WINDOW_XID (rootwin));
		}
	}
}

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

	EggVirtualModifierType virtual_mods = (EggVirtualModifierType)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 key string %s\n", binding->keystring));
	TRACE (g_print ("Got accel %d ('%c'), %d\n", keysym, (char)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);

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

	gdk_error_trap_push ();

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

	gint error = gdk_error_trap_pop();
	if (error) {
		if(error == BadAccess)
			g_warning("Binding '%s' failed! Already assigned.\n", binding->keystring);
		else
			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, gpointer data)
{
	GdkFilterReturn return_val = GDK_FILTER_CONTINUE;
	XEvent *xevent = (XEvent *) gdk_xevent;
	GdkModifierType 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 = static_cast<GdkModifierType>(
			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) ();
			}
		}

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

	return return_val;
}

static void
keymap_changed (GdkKeymap *map)
{
	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_XDISPLAY(gdk_display_get_default()));

	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;
}
