/* -*- Mode: C++; indent-tabs-mode: nil; tab-width: 4 -*-
 * -*- coding: utf-8 -*-
 *
 * Copyright (C) 2020 KylinSoft Co., Ltd.
 *
 * This program 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
 * any later version.
 *
 * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#include "config.h"
#include "ukui-keygrab.h"

#ifdef HAVE_X11_EXTENSIONS_XKB_H
#include <X11/XKBlib.h>
#include <X11/extensions/XKB.h>
#include <gdk/gdkkeysyms.h>
#include <gdk/gdkx.h>
#endif

#include "eggaccelerators.h"

/* these are the mods whose combinations are ignored by the keygrabbing code */
static GdkModifierType usd_ignored_mods = (GdkModifierType)0;

/* these are the ones we actually use for global keys, we always only check
 * for these set */
static GdkModifierType usd_used_mods = (GdkModifierType)0;

static void
setup_modifiers (void)
{
    if (usd_used_mods == 0 || usd_ignored_mods == 0) {
        GdkModifierType dynmods;

        /* default modifiers */
        usd_ignored_mods = \
                GdkModifierType(0x2000 /*Xkb modifier*/ | GDK_LOCK_MASK | GDK_HYPER_MASK);
        usd_used_mods = \
                    GdkModifierType(GDK_SHIFT_MASK | GDK_CONTROL_MASK |\
                    GDK_MOD1_MASK | GDK_MOD2_MASK | GDK_MOD3_MASK | GDK_MOD4_MASK |\
                    GDK_MOD5_MASK | GDK_SUPER_MASK | GDK_META_MASK);

        /* NumLock can be assigned to varying keys so we need to
         * resolve and ignore it specially */
        dynmods = (GdkModifierType)0;
        egg_keymap_resolve_virtual_modifiers (gdk_keymap_get_for_display(gdk_display_get_default()),
                                              EGG_VIRTUAL_NUM_LOCK_MASK,
                                              &dynmods);

        usd_ignored_mods = GdkModifierType (usd_ignored_mods | dynmods);
        usd_used_mods = GdkModifierType (usd_used_mods & ~dynmods);

        dynmods = (GdkModifierType)0;
        egg_keymap_resolve_virtual_modifiers (gdk_keymap_get_for_display(gdk_display_get_default()),
                                              EGG_VIRTUAL_SCROLL_LOCK_MASK,
                                              &dynmods);

        usd_ignored_mods = GdkModifierType (usd_ignored_mods | dynmods);
        usd_used_mods = GdkModifierType (usd_used_mods & ~dynmods);

	}
}

static void
grab_key_real (guint      keycode,
               GdkWindow *root,
               bool   grab,
               int        mask)
{
        if (grab) {
                XGrabKey (GDK_DISPLAY_XDISPLAY(gdk_display_get_default()),
                          keycode,
                          mask,
                          GDK_WINDOW_XID (root),
                          True,
                          GrabModeAsync,
                          GrabModeAsync);
        } else {
                XUngrabKey (GDK_DISPLAY_XDISPLAY(gdk_display_get_default()),
                            keycode,
                            mask,
                            GDK_WINDOW_XID (root));
        }
}

/* Grab the key. In order to ignore USD_IGNORED_MODS we need to grab
 * all combinations of the ignored modifiers and those actually used
 * for the binding (if any).
 *
 * inspired by all_combinations from ukui-panel/ukui-panel/global-keys.c
 *
 * This may generate X errors.  The correct way to use this is like:
 *
 *        gdk_error_trap_push ();
 *
 *        grab_key_unsafe (key, grab, screens);
 *
 *        gdk_flush ();
 *        if (gdk_error_trap_pop ())
 *                g_warning ("Grab failed, another application may already have access to key '%u'",
 *                           key->keycode);
 *
 * This is not done in the function itself, to allow doing multiple grab_key
 * operations with one flush only.
 */
#define N_BITS 32
void
grab_key_unsafe (Key                 *key,
                 bool             grab,
                 QList<GdkScreen*>   *screens)
{
        int   indexes[N_BITS]; /* indexes of bits we need to flip */
        int   i;
        int   bit;
        int   bits_set_cnt;
        int   uppervalue;
        guint mask;

        setup_modifiers ();

        mask = usd_ignored_mods & ~key->state & GDK_MODIFIER_MASK;

        bit = 0;
        /* store the indexes of all set bits in mask in the array */
        for (i = 0; mask; ++i, mask >>= 1) {
                if (mask & 0x1) {
                        indexes[bit++] = i;
                }
        }

        bits_set_cnt = bit;

        uppervalue = 1 << bits_set_cnt;
        /* grab all possible modifier combinations for our mask */
        for (i = 0; i < uppervalue; ++i) {
                QList<GdkScreen*>::iterator l,begin,end;
                int     j;
                int     result = 0;

                /* map bits in the counter to those in the mask */
                for (j = 0; j < bits_set_cnt; ++j) {
                        if (i & (1 << j)) {
                                result |= (1 << indexes[j]);
                        }
                }

                l = begin = screens->begin();
                end = screens->end();
                for (; l != end; ++l) {
                        GdkScreen *screen = *l;
                        GdkWindow *window = gdk_screen_get_root_window (screen);
                        guint *code = key->keycodes ;
                        for (; code&&(*code); ++code) {
                                grab_key_real (*code,
                                               window,
                                               grab,
                                               result | key->state);
                        }
                }
        }
}

static gboolean
have_xkb (Display *dpy)
{
	static int have_xkb = -1;

	if (have_xkb == -1) {
#ifdef HAVE_X11_EXTENSIONS_XKB_H
		int opcode, error_base, major, minor, xkb_event_base;

		have_xkb = XkbQueryExtension (dpy,
					      &opcode,
					      &xkb_event_base,
					      &error_base,
					      &major,
					      &minor)
			&& XkbUseExtension (dpy, &major, &minor);
#else
		have_xkb = 0;
#endif
	}

	return have_xkb;
}

gboolean
key_uses_keycode (const Key *key, guint keycode)
{
	if (key->keycodes != NULL) {
		guint *c;

		for (c = key->keycodes; *c; ++c) {
			if (*c == keycode)
				return TRUE;
		}
	}
	return FALSE;
}

gboolean
match_key (Key *key, XEvent *event)
{
	guint keyval;
	GdkModifierType consumed;
	gint group;

	if (key == NULL)
		return FALSE;

	setup_modifiers ();

#ifdef HAVE_X11_EXTENSIONS_XKB_H
	if (have_xkb (event->xkey.display))
		group = XkbGroupForCoreState (event->xkey.state);
	else
#endif
		group = (event->xkey.state & GDK_KEY_Mode_switch) ? 1 : 0;

	/* Check if we find a keysym that matches our current state */
    if (gdk_keymap_translate_keyboard_state (gdk_keymap_get_for_display(gdk_display_get_default()), event->xkey.keycode,
                         (GdkModifierType)event->xkey.state, group,
					     &keyval, NULL, NULL, &consumed)) {
		guint lower, upper;

		gdk_keyval_convert_case (keyval, &lower, &upper);

		/* If we are checking against the lower version of the
		 * keysym, we might need the Shift state for matching,
		 * so remove it from the consumed modifiers */
		if (lower == key->keysym)
            consumed = GdkModifierType (consumed & ~GDK_SHIFT_MASK);

		return ((lower == key->keysym || upper == key->keysym)
			&& (event->xkey.state & ~consumed & usd_used_mods) == key->state);
	}

	/* The key we passed doesn't have a keysym, so try with just the keycode */
        return (key != NULL
                && key->state == (event->xkey.state & usd_used_mods)
                && key_uses_keycode (key, event->xkey.keycode));
}
