/*
Copyright 2011 Canonical Ltd.

Authors:
    Conor Curran <conor.curran@canonical.com>

This program is free software: you can redistribute it and/or modify it 
under the terms of the GNU General Public License version 3, as published 
by the Free Software Foundation.

This program is distributed in the hope that it will be useful, but 
WITHOUT ANY WARRANTY; without even the implied warranties of 
MERCHANTABILITY, SATISFACTORY QUALITY, 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 <libdbusmenu-glib/client.h>
#include "user-menu-mgr.h"
#include "settings-helper.h"
#include "dbus-shared-names.h"
#include "dbusmenu-shared.h"
#include "lock-helper.h"
#include "users-service-dbus.h"

struct ActivateUserSessionData
{
  UserMenuMgr * menu_mgr;
  UserData * user;
};

struct _UserMenuMgr
{
  GObject parent_instance;
  UsersServiceDbus* users_dbus_interface;
  DbusmenuMenuitem* root_item;
  SessionDbus* session_dbus_interface;  
  GSettings * lockdown_settings;
};

static void activate_new_session (DbusmenuMenuitem * mi,
                                  guint timestamp,
                                  gpointer user_data);
static void activate_user_session (DbusmenuMenuitem *mi,
                                   guint timestamp,
                                   gpointer user_data);
static void activate_user_accounts (DbusmenuMenuitem *mi,
                                    guint timestamp,
                                    gpointer user_data);
static gint compare_users_by_username (gconstpointer a,
                                       gconstpointer b);
static void activate_user_accounts (DbusmenuMenuitem *mi,
                                    guint timestamp,
                                    gpointer user_data);                                      
static void user_menu_mgr_rebuild_items (UserMenuMgr *self,
                                         gboolean greeter_mode);
static void user_change (UsersServiceDbus *service,
                         const gchar      *user_id,
                         gpointer          user_data);
static gboolean is_this_guest_session (void);
static void activate_guest_session (DbusmenuMenuitem * mi,
                                    guint timestamp,
                                    gpointer user_data);
                                    

G_DEFINE_TYPE (UserMenuMgr, user_menu_mgr, G_TYPE_OBJECT);


static void
user_menu_mgr_init (UserMenuMgr *self)
{
  self->lockdown_settings = g_settings_new (LOCKDOWN_SCHEMA);
  self->users_dbus_interface = g_object_new (USERS_SERVICE_DBUS_TYPE, NULL);
  self->root_item = dbusmenu_menuitem_new ();
  g_signal_connect (G_OBJECT (self->users_dbus_interface),
                    "user-added",
                    G_CALLBACK (user_change),
                    self);
  g_signal_connect (G_OBJECT (self->users_dbus_interface),
                    "user-deleted",
                    G_CALLBACK (user_change),
                    self);
}

static void
user_menu_mgr_dispose (GObject *object)
{
  UserMenuMgr * menu_mgr = USER_MENU_MGR(object);

  g_clear_object (&menu_mgr->users_dbus_interface);
  g_clear_object (&menu_mgr->lockdown_settings);
}

static void
user_menu_mgr_finalize (GObject *object)
{
  /* TODO: Add deinitalization code here */
  G_OBJECT_CLASS (user_menu_mgr_parent_class)->finalize (object);
}

static void
user_menu_mgr_class_init (UserMenuMgrClass *klass)
{
  GObjectClass* object_class = G_OBJECT_CLASS (klass);
  object_class->dispose = user_menu_mgr_dispose;
  object_class->finalize = user_menu_mgr_finalize;
}

static DbusmenuMenuitem*
create_user_menuitem (UserMenuMgr * menu_mgr, UserData * user)
{
  DbusmenuMenuitem * mi = dbusmenu_menuitem_new ();
  dbusmenu_menuitem_property_set (mi,
                                  DBUSMENU_MENUITEM_PROP_TYPE,
                                  USER_ITEM_TYPE);

  /* set the name property */
  char * str = user->real_name_conflict
             ? g_strdup_printf ("%s (%s)", user->real_name, user->user_name)
             : g_strdup (user->real_name);
  dbusmenu_menuitem_property_set (mi, USER_ITEM_PROP_NAME, str);
  g_free (str);

  /* set the logged-in property */
  dbusmenu_menuitem_property_set_bool (mi,
                                       USER_ITEM_PROP_LOGGED_IN,
                                       user->sessions != NULL);

  /* set the icon property */
  str = user->icon_file;
  if (!str || !*str)
    str = USER_ITEM_ICON_DEFAULT;
  dbusmenu_menuitem_property_set (mi, USER_ITEM_PROP_ICON, str);

  /* set the is-current-user property */
  dbusmenu_menuitem_property_set_bool (mi,
                                       USER_ITEM_PROP_IS_CURRENT_USER,
                                       !g_strcmp0 (user->user_name, g_get_user_name()));

  /* set the activate callback */
  struct ActivateUserSessionData * data = g_new (struct ActivateUserSessionData, 1);
  data->user = user;
  data->menu_mgr = menu_mgr;
  g_signal_connect_data (mi, DBUSMENU_MENUITEM_SIGNAL_ITEM_ACTIVATED,
                         G_CALLBACK (activate_user_session),
                         data, (GClosureNotify)g_free,
                         0);

  /* done */
  return mi;
}

/* Builds up the menu for us */
static void 
user_menu_mgr_rebuild_items (UserMenuMgr *self, gboolean greeter_mode)
{
  GList *u;
  gboolean can_activate;
  GList *children;

  /* Check to see which menu items we're allowed to have */
  can_activate = users_service_dbus_can_activate_session (self->users_dbus_interface) &&
      !g_settings_get_boolean (self->lockdown_settings, LOCKDOWN_KEY_USER);

  /* Remove the old menu items if that makes sense */
  children = dbusmenu_menuitem_take_children (self->root_item);
  g_list_foreach (children, (GFunc)g_object_unref, NULL);
  g_list_free (children);

  /* Set to NULL just incase we don't end up building one */
  users_service_dbus_set_guest_item(self->users_dbus_interface, NULL);

  /* Build all of the user switching items */
  if (can_activate == TRUE)
  {
    
    gboolean guest_enabled = users_service_dbus_guest_session_enabled (self->users_dbus_interface);
    GList * users = NULL;
    users = users_service_dbus_get_user_list (self->users_dbus_interface);
    const gint user_count = g_list_length(users);
    
    gboolean gsettings_user_menu_is_visible = should_show_user_menu();
    
    if (gsettings_user_menu_is_visible == FALSE || greeter_mode == TRUE){
      session_dbus_set_user_menu_visibility (self->session_dbus_interface,
                                             FALSE);
    }
    else{
      // This needs to be updated once the ability to query guest session support is available
      session_dbus_set_user_menu_visibility (self->session_dbus_interface,
                                             guest_enabled || user_count > 1);
    }
    
    // TODO we should really return here if the menu is not going to be shown.
    
    DbusmenuMenuitem * switch_menuitem = dbusmenu_menuitem_new ();
    dbusmenu_menuitem_property_set (switch_menuitem,
                                    DBUSMENU_MENUITEM_PROP_TYPE,
                                    MENU_SWITCH_TYPE);
    dbusmenu_menuitem_property_set (switch_menuitem,
                                    MENU_SWITCH_USER,
                                    g_get_user_name());
    dbusmenu_menuitem_child_append (self->root_item, switch_menuitem);
    g_signal_connect (G_OBJECT (switch_menuitem),
                      DBUSMENU_MENUITEM_SIGNAL_ITEM_ACTIVATED,
                      G_CALLBACK (activate_new_session),
                      self);
    
    if ( !is_this_guest_session () && guest_enabled)
    {
      DbusmenuMenuitem *guest_mi = NULL;
      guest_mi = dbusmenu_menuitem_new ();
      dbusmenu_menuitem_property_set (guest_mi,
                                      DBUSMENU_MENUITEM_PROP_TYPE,
                                      USER_ITEM_TYPE);
      dbusmenu_menuitem_property_set (guest_mi,
                                      USER_ITEM_PROP_NAME,
                                      _("Guest Session"));
      dbusmenu_menuitem_property_set_bool (guest_mi,
                                           USER_ITEM_PROP_LOGGED_IN,
                                           FALSE);
      dbusmenu_menuitem_child_append (self->root_item, guest_mi);
      g_signal_connect (G_OBJECT (guest_mi),
                        DBUSMENU_MENUITEM_SIGNAL_ITEM_ACTIVATED,
                        G_CALLBACK (activate_guest_session),
                        self);
      users_service_dbus_set_guest_item (self->users_dbus_interface,
                                         guest_mi);
    }
    else{
      session_dbus_set_users_real_name (self->session_dbus_interface,
                                        _("Guest"));      
    }
    
    

    users = g_list_sort (users, compare_users_by_username);

    for (u = users; u != NULL; u = g_list_next (u))
      {
        UserData * user = u->data;

        DbusmenuMenuitem * mi = create_user_menuitem (self, user);
        dbusmenu_menuitem_child_append (self->root_item, mi);

        if (!g_strcmp0 (user->user_name, g_get_user_name()))
          {
            session_dbus_set_users_real_name (self->session_dbus_interface, user->real_name);
          }
      }

    g_list_free(users);
  }

  // Add the user accounts and separator
  DbusmenuMenuitem * separator1 = dbusmenu_menuitem_new();
  dbusmenu_menuitem_property_set (separator1,
                                  DBUSMENU_MENUITEM_PROP_TYPE,
                                  DBUSMENU_CLIENT_TYPES_SEPARATOR);
  dbusmenu_menuitem_child_append (self->root_item, separator1);

  DbusmenuMenuitem * user_accounts_item = dbusmenu_menuitem_new();
  dbusmenu_menuitem_property_set (user_accounts_item,
                                  DBUSMENU_MENUITEM_PROP_TYPE,
                                  DBUSMENU_CLIENT_TYPES_DEFAULT);
  dbusmenu_menuitem_property_set (user_accounts_item,
                                  DBUSMENU_MENUITEM_PROP_LABEL,
                                  _("User Accounts…"));

  g_signal_connect (G_OBJECT (user_accounts_item),
                    DBUSMENU_MENUITEM_SIGNAL_ITEM_ACTIVATED,
                    G_CALLBACK (activate_user_accounts),
                    NULL);
                                  
  dbusmenu_menuitem_child_append (self->root_item, user_accounts_item); 


}

/* Check to see if the lockdown key is protecting from
   locking the screen.  If not, lock it. */
static void
lock_if_possible (UserMenuMgr * menu_mgr)
{
  if (!g_settings_get_boolean (menu_mgr->lockdown_settings, LOCKDOWN_KEY_SCREENSAVER))
    {
      lock_screen(NULL, 0, NULL);
    }
}

/* Starts a new generic session */
static void
activate_new_session (DbusmenuMenuitem * mi, guint timestamp, gpointer user_data)
{
  UserMenuMgr * menu_mgr = USER_MENU_MGR (user_data);
  g_return_if_fail (menu_mgr != NULL);

  lock_if_possible (menu_mgr);
  users_service_dbus_show_greeter (menu_mgr->users_dbus_interface);
}

/* Activates a session for a particular user. */
static void
activate_user_session (DbusmenuMenuitem *mi, guint timestamp, gpointer user_data)
{
  struct ActivateUserSessionData * data = user_data;

  lock_if_possible (data->menu_mgr);
  users_service_dbus_activate_user_session (data->menu_mgr->users_dbus_interface, data->user);
}

/* Comparison function to look into the UserData struct
   to compare by using the username value */
static gint
compare_users_by_username (gconstpointer a, gconstpointer b)
{
  UserData *user1 = (UserData *)a;
  UserData *user2 = (UserData *)b;

  gint retval = g_strcmp0 (user1->real_name, user2->real_name);

  /* If they're the same, they're both in conflict. */
  if (retval == 0) {
    user1->real_name_conflict = TRUE;
    user2->real_name_conflict = TRUE;
  }

  return retval;
}

static void
activate_user_accounts (DbusmenuMenuitem *mi,
                          guint timestamp,
                          gpointer user_data)
{
  GError * error = NULL;
  if (!g_spawn_command_line_async("gnome-control-center user-accounts", &error))
  {
    g_warning("Unable to show control centre: %s", error->message);
    g_error_free(error);
  }
}

/* Signal called when a user is added.  It updates the count and
   rebuilds the menu */
static void
user_change (UsersServiceDbus *service,
             const gchar      *user_id,
             gpointer          user_data)
{
  g_return_if_fail (USER_IS_MENU_MGR (user_data));  
  UserMenuMgr* user_mgr = USER_MENU_MGR(user_data);  
	user_menu_mgr_rebuild_items (user_mgr, FALSE);
	return;
}

DbusmenuMenuitem*
user_mgr_get_root_item (UserMenuMgr* self)
{
  return self->root_item;
}

/* Checks to see if we should show the guest session item.
   System users shouldn't have guest account shown.
   Mostly this would be the case of the guest user itself. */
static gboolean
is_this_guest_session (void)
{
  return geteuid() < 500;
}

/* Called when someone clicks on the guest session item. */
static void
activate_guest_session (DbusmenuMenuitem * mi, guint timestamp, gpointer user_data)
{
  UserMenuMgr * menu_mgr = USER_MENU_MGR (user_data);
  g_return_if_fail (menu_mgr != NULL);

  lock_if_possible (menu_mgr);
  users_service_dbus_activate_guest_session (menu_mgr->users_dbus_interface);
}


/*
 * Clean Entry Point 
 */
UserMenuMgr* user_menu_mgr_new (SessionDbus* session_dbus, gboolean greeter_mode)
{
  UserMenuMgr* user_mgr = g_object_new (USER_TYPE_MENU_MGR, NULL);
  user_mgr->session_dbus_interface = session_dbus;
  user_menu_mgr_rebuild_items (user_mgr, greeter_mode);    
  return user_mgr;
}