/*
 * Copyright © 2018 Benjamin Otte
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library. If not, see <http://www.gnu.org/licenses/>.
 *
 * Authors: Benjamin Otte <otte@gnome.org>
 */

#include "config.h"

#include "gtkshortcut.h"

#include "gtkbindingsprivate.h"
#include "gtkintl.h"
#include "gtkwidget.h"

/**
 * SECTION:gtkshortcut
 * @title: GtkShortcut
 * @short_description: An object describing a keyboard shortcut
 * @see_also: #GtkShortcutController, #GtkShortcutTrigger
 *
 * GtkShortcut is the low level object used for managing keyboard
 * shortcuts.
 *
 * It contains a description of how to trigger the shortcut via a
 * #GtkShortcutTrigger and a way to activate the shortcut on a widget
 * with gtk_shortcut_activate().
 *
 * The actual work is usually done via #GtkShortcutController, which
 * decides if and when to activate a shortcut. Using that controller
 * directly however is rarely necessary as Various higher level
 * convenience APIs exist on #GtkWidgets that make it easier to use
 * shortcuts in GTK.
 *
 * #GtkShortcut does provide functionality to make it easy for users
 * to work with shortcuts, either by providing informational strings
 * for display purposes or by allowing shortcuts to be configured.
 */

struct _GtkShortcut
{
  GObject parent_instance;

  GdkModifierType mods;
  guint keyval;

  char *signal;
  GVariant *args;
};

enum
{
  PROP_0,
  PROP_ARGUMENTS,
  PROP_SIGNAL,

  N_PROPS
};

G_DEFINE_TYPE (GtkShortcut, gtk_shortcut, G_TYPE_OBJECT)

static GParamSpec *properties[N_PROPS] = { NULL, };

static void
gtk_shortcut_dispose (GObject *object)
{
  GtkShortcut *self = GTK_SHORTCUT (object);

  g_clear_pointer (&self->signal, g_free);
  g_clear_pointer (&self->args, g_variant_unref);

  G_OBJECT_CLASS (gtk_shortcut_parent_class)->dispose (object);
}

static void
gtk_shortcut_get_property (GObject    *object,
                           guint       property_id,
                           GValue     *value,
                           GParamSpec *pspec)
{
  GtkShortcut *self = GTK_SHORTCUT (object);

  switch (property_id)
    {
    case PROP_ARGUMENTS:
      g_value_set_variant (value, self->args);
      break;

    case PROP_SIGNAL:
      g_value_set_string (value, self->signal);
      break;

    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
      break;
    }
}

static void
gtk_shortcut_set_property (GObject      *object,
                           guint         property_id,
                           const GValue *value,
                           GParamSpec   *pspec)
{
  GtkShortcut *self = GTK_SHORTCUT (object);

  switch (property_id)
    {
    case PROP_ARGUMENTS:
      gtk_shortcut_set_arguments (self, g_value_get_variant (value));
      break;

    case PROP_SIGNAL:
      gtk_shortcut_set_signal (self, g_value_get_string (value));
      break;

    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
      break;
    }
}

static void
gtk_shortcut_class_init (GtkShortcutClass *klass)
{
  GObjectClass *gobject_class = G_OBJECT_CLASS (klass);

  gobject_class->dispose = gtk_shortcut_dispose;
  gobject_class->get_property = gtk_shortcut_get_property;
  gobject_class->set_property = gtk_shortcut_set_property;

  /**
   * GtkShortcut:arguments:
   *
   * Arguments passed to activation.
   */
  properties[PROP_ARGUMENTS] =
    g_param_spec_variant ("arguments",
                          P_("Arguments"),
                          P_("Arguments passed to activation"),
                          G_VARIANT_TYPE_ANY,
                          NULL,
                          G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);

  /**
   * GtkShortcut:signal:
   *
   * The action signal to emit on the widget upon activation.
   */
  properties[PROP_SIGNAL] =
    g_param_spec_string ("signal",
                         P_("Signal"),
                         P_("The action signal to emit"),
                         NULL,
                         G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS);

  g_object_class_install_properties (gobject_class, N_PROPS, properties);
}

static void
gtk_shortcut_init (GtkShortcut *self)
{
}

/**
 * gtk_shortcut_new:
 *
 * Creates a new empty #GtkShortcut that never triggers and activates nothing.
 *
 * Returns: a new #GtkShortcut
 **/
GtkShortcut *
gtk_shortcut_new (void)
{
  return g_object_new (GTK_TYPE_SHORTCUT, NULL);
}

void
gtk_shortcut_set_keyval (GtkShortcut     *self,
                         guint            keyval,
                         GdkModifierType  mods)
{
  g_return_if_fail (GTK_IS_SHORTCUT (self));

  /* To deal with <Shift>, we need to uppercase
   * or lowercase depending on situation.
   */
  if (mods & GDK_SHIFT_MASK)
    {
      if (keyval == GDK_KEY_Tab)
        keyval = GDK_KEY_ISO_Left_Tab;
      else
        keyval = gdk_keyval_to_upper (keyval);
    }
  else
    {
      if (keyval == GDK_KEY_ISO_Left_Tab)
        keyval = GDK_KEY_Tab;
      else
        keyval = gdk_keyval_to_lower (keyval);
    }

  self->keyval = keyval;
  self->mods = mods;
}

gboolean
gtk_shortcut_trigger (GtkShortcut *self,
                      GdkEvent    *event)
{
  GdkModifierType mods;
  guint keyval;

  if (gdk_event_get_event_type (event) != GDK_KEY_PRESS)
    return FALSE;

  /* XXX: This needs to deal with groups */
  mods = gdk_event_get_modifier_state (event);
  keyval = gdk_key_event_get_keyval (event);

  return keyval == self->keyval && mods == self->mods;
}

gboolean
gtk_shortcut_activate (GtkShortcut *self,
                       GtkWidget   *widget)
{
  g_return_val_if_fail (GTK_IS_SHORTCUT (self), FALSE);
  g_return_val_if_fail (GTK_IS_WIDGET (widget), FALSE);

  if (self->signal)
    {
      GError *error = NULL;
      gboolean handled;

      if (!gtk_binding_emit_signal (G_OBJECT (widget),
                                    self->signal,
                                    self->args,
                                    &handled,
                                    &error))
        {
          char *accelerator = gtk_accelerator_name (self->keyval, self->mods);
          g_warning ("gtk_shortcut_activate(): \":%s\": %s",
                     accelerator,
                     error->message);
          g_clear_error (&error);
          return FALSE;
        }

      return handled;
    }
  else
    {
      /* shortcut is a dud */
      return FALSE;
    }
}

GVariant *
gtk_shortcut_get_arguments (GtkShortcut *self)
{
  g_return_val_if_fail (GTK_IS_SHORTCUT (self), NULL);

  return self->args;
}

void
gtk_shortcut_set_arguments (GtkShortcut *self,
                            GVariant    *args)
{
  g_return_if_fail (GTK_IS_SHORTCUT (self));

  if (self->args == args)
    return;
  
  g_clear_pointer (&self->args, g_variant_unref);
  if (args)
    self->args = g_variant_ref_sink (args);

  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_ARGUMENTS]);
}

const char *
gtk_shortcut_get_signal (GtkShortcut *self)
{
  g_return_val_if_fail (GTK_IS_SHORTCUT (self), NULL);

  return self->signal;
}

void
gtk_shortcut_set_signal (GtkShortcut *self,
                         const gchar *signal)
{
  g_return_if_fail (GTK_IS_SHORTCUT (self));

  if (g_strcmp0 (self->signal, signal) == 0)
    return;
  
  g_clear_pointer (&self->signal, g_free);
  self->signal = g_strdup (signal);

  g_object_notify_by_pspec (G_OBJECT (self), properties[PROP_SIGNAL]);
}