/*
  NotificationService  -  public service allowing to push information into the GUI

  Copyright (C)         Lumiera.org
    2008,               Hermann Vosseler <Ichthyostega@web.de>

  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 2 of
  the License, or (at your option) 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, write to the Free Software
  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

* *****************************************************/

/** @file notification-service.cpp
 ** Implementation of notifications and updates within the GUI.
 ** This is the actual service implementation and runs within the GUI plugin.
 ** 
 ** Since GTK is _not threadsafe by design,_ any external invocation passed through
 ** this facade service will be dispatched explicitly into the GTK event loop thread.
 ** The implementation of this dispatch is based upon `Glib::Dispatcher` and thus
 ** requires this service instance to be created from within the thread performing
 ** the GTK event loop. Moreover, to avoid segmentation faults on shutdown, the
 ** lifespan of this service instance must exceed the running of the event loop,
 ** since otherwise the event loop might invoke a lambda bound to the `this`
 ** pointer of a NotificationService already decommissioned. The setup of the
 ** standard Lumiera UI top-level context ensures this is the case, since the
 ** UiManager::performMainLoop() maintains the NotificationService instance
 ** and also performs the blocking `gtk_main()` call. Consequently, any
 ** invocation added from other threads after leaving the GTK main loop
 ** but before closing the GuiNotification facade will just be enqueued,
 ** but then dropped on destruction of the UiDispatcher PImpl.
 ** 
 ** @see ui-dispatcher.hpp
 ** 
 */



#include "gui/ctrl/ui-manager.hpp"
#include "gui/ctrl/ui-dispatcher.hpp"
#include "gui/notification-service.hpp"
#include "lib/diff/mutation-message.hpp"
#include "lib/diff/gen-node.hpp"
#include "include/logging.h"
#include "lib/depend.hpp"
#include "lib/util.hpp"

extern "C" {
#include "common/interface-descriptor.h"
}

#include <string>


using lib::diff::GenNode;
using lib::diff::TreeMutator;
using lib::diff::MutationMessage;
using gui::ctrl::UiDispatcher;
using gui::ctrl::BusTerm;
using std::string;
using util::cStr;


namespace gui {
  
  
  /** @internal helper to _move_ a given UI-Bus message (GenNode)
   *   into the closure of an event-lambda, which then is handed over
   *   to the UI event thread through the dispatcher queue.
   */
  void
  NotificationService::dispatchMsg (ID uiElement, lib::diff::GenNode&& uiMessage)
  {
    dispatch_->event ([=]()
                      {
                        this->mark (uiElement, uiMessage);
                      });
  }
  
  
  void 
  NotificationService::displayInfo (NotifyLevel severity, string const& text)
  {
    INFO (gui, "@GUI: display '%s' as notification message.", cStr(text));  ///////////////////////////////////TICKET #1102 : build a message display box in the UI
    ////////////////////////TODO actually push the information to the GUI   ///////////////////////////////////TICKET #1098 : use a suitable Dispatcher
                                                               ////////////////////////////////////////////////TICKET #1047 : as a temporary solution, use the InfoBox panel... 
  }
  
  
  void
  NotificationService::markError (ID uiElement, string const& text)
  {
    dispatchMsg (uiElement, GenNode{"Error", text});
  }
  
  
  void
  NotificationService::markNote  (ID uiElement, string const& text)
  {
    dispatchMsg (uiElement, GenNode{"Message", text});
  }
  
  
  void
  NotificationService::mutate (ID uiElement, MutationMessage&& diff)
  {
    dispatch_->event ([=]()                                                  //////////////////////////////////TODO care for error handling!!!
                      {
                        // apply and consume diff message stored within closure
                        this->change (uiElement, move(unConst(diff)));
                      });
  }
  
  
  void
  NotificationService::triggerGuiShutdown (string const& cause)
  {
    NOTICE (gui, "@GUI: shutdown triggered with explanation '%s'....", cStr(cause));
    displayInfo (NOTE_ERROR, cause);
    dispatch_->event ([this]()
                      {
                        uiManager_.terminateUI();
                      });
  }
  
  
  
  namespace { // facade implementation details
    
    
    /* ================== define an lumieraorg_GuiNotification instance ======================= */
    
    LUMIERA_INTERFACE_INSTANCE (lumieraorg_interfacedescriptor, 0
                               ,lumieraorg_GuiNotificationFacade_descriptor
                               , NULL, NULL, NULL
                               , LUMIERA_INTERFACE_INLINE (name,
                                                           const char*, (LumieraInterface ifa),
                                                             { (void)ifa;  return "GuiNotification"; }
                                                          )
                               , LUMIERA_INTERFACE_INLINE (brief,
                                                           const char*, (LumieraInterface ifa),
                                                             { (void)ifa;  return "GUI Interface: push state update and notification of events into the GUI"; }
                                                          )
                               , LUMIERA_INTERFACE_INLINE (homepage,
                                                           const char*, (LumieraInterface ifa),
                                                             { (void)ifa;  return "http://www.lumiera.org/develompent.html" ;}
                                                          )
                               , LUMIERA_INTERFACE_INLINE (version,
                                                           const char*, (LumieraInterface ifa),
                                                             { (void)ifa;  return "0.1~pre"; }
                                                          )
                               , LUMIERA_INTERFACE_INLINE (author,
                                                           const char*, (LumieraInterface ifa),
                                                             { (void)ifa;  return "Hermann Vosseler"; }
                                                          )
                               , LUMIERA_INTERFACE_INLINE (email,
                                                           const char*, (LumieraInterface ifa),
                                                             { (void)ifa;  return "Ichthyostega@web.de"; }
                                                          )
                               , LUMIERA_INTERFACE_INLINE (copyright,
                                                           const char*, (LumieraInterface ifa),
                                                             {
                                                               (void)ifa;
                                                               return
                                                                 "Copyright (C)        Lumiera.org\n"
                                                                 "  2008               Hermann Vosseler <Ichthyostega@web.de>";
                                                             }
                                                          )
                               , LUMIERA_INTERFACE_INLINE (license,
                                                           const char*, (LumieraInterface ifa),
                                                             {
                                                               (void)ifa;
                                                               return
                                                                 "This program is free software; you can redistribute it and/or modify\n"
                                                                 "it under the terms of the GNU General Public License as published by\n"
                                                                 "the Free Software Foundation; either version 2 of the License, or\n"
                                                                 "(at your option) any later version.\n"
                                                                 "\n"
                                                                 "This program is distributed in the hope that it will be useful,\n"
                                                                 "but WITHOUT ANY WARRANTY; without even the implied warranty of\n"
                                                                 "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n"
                                                                 "GNU General Public License for more details.\n"
                                                                 "\n"
                                                                 "You should have received a copy of the GNU General Public License\n"
                                                                 "along with this program; if not, write to the Free Software\n"
                                                                 "Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA";
                                                             }
                                                          )
                               , LUMIERA_INTERFACE_INLINE (state,
                                                           int, (LumieraInterface ifa),
                                                             {(void)ifa;  return LUMIERA_INTERFACE_EXPERIMENTAL; }
                                                          )
                               , LUMIERA_INTERFACE_INLINE (versioncmp,
                                                           int, (const char* a, const char* b),
                                                             {(void)a;(void)b;  return 0;}  ////////////////////////////////////////////TODO define version ordering
                                                          )
                               );
    
    
    
    
    
    using lumiera::error::LERR_(LIFECYCLE);
    
    lib::Depend<NotificationService> _instance; ///< a backdoor for the C Language impl to access the actual SessionCommand implementation...
    
    
    
    LUMIERA_INTERFACE_INSTANCE (lumieraorg_GuiNotification, 0
                               ,lumieraorg_GuiNotificationService
                               , LUMIERA_INTERFACE_REF(lumieraorg_interfacedescriptor, 0, lumieraorg_GuiNotificationFacade_descriptor)
                               , NULL /* on  open  */
                               , NULL /* on  close */
                               , LUMIERA_INTERFACE_INLINE (displayInfo,
                                                           void, (uint severity, const char* text),
                                                             {
                                                               if (!_instance) lumiera_error_set (LUMIERA_ERROR_LIFECYCLE, text);
                                                               else
                                                                 _instance().displayInfo (NotifyLevel(severity), text);
                                                             }
                                                          )
                               , LUMIERA_INTERFACE_INLINE (markError,
                                                           void, (LumieraUid element, const char* text),
                                                             {
                                                               if (!_instance) lumiera_error_set (LUMIERA_ERROR_LIFECYCLE, text);
                                                               else
                                                                 _instance().markError (reinterpret_cast<ID> (*element), text);
                                                             }
                                                          )
                               , LUMIERA_INTERFACE_INLINE (markNote,
                                                           void, (LumieraUid element, const char* text),
                                                             {
                                                               if (!_instance) lumiera_error_set (LUMIERA_ERROR_LIFECYCLE, text);
                                                               else
                                                                 _instance().markNote (reinterpret_cast<ID> (*element), text);
                                                             }
                                                          )
                               , LUMIERA_INTERFACE_INLINE (mutate,
                                                           void, (LumieraUid element, void* diff),
                                                             {
                                                               if (!_instance) lumiera_error_set (LUMIERA_ERROR_LIFECYCLE, "passing diff message");
                                                               else
                                                                 _instance().mutate (reinterpret_cast<ID> (*element), move(*reinterpret_cast<MutationMessage*> (diff)));
                                                             }
                                                          )
                               , LUMIERA_INTERFACE_INLINE (triggerGuiShutdown,
                                                           void, (const char* cause),
                                                             {
                                                               if (!_instance) lumiera_error_set (LUMIERA_ERROR_LIFECYCLE, cause);
                                                               else
                                                                 _instance().triggerGuiShutdown (cause);
                                                             }
                                                          )
                               );
    
    
    
  } // (END) facade implementation details
  
  
  
  
  /**
   * When started, NotificationService connects to the [UI-Bus](ui-bus.hpp) via the provided connection.
   * This is a simple, unidirectional up-link connection, without actively adding NotificationService
   * into the routing tables in [Nexus]. Yet this simple connection is sufficient to implement this
   * service by talking to other facilities within the UI layer.
   * @remark internally this service relies on a UiDispatcher queue to hand over any invocations
   *         into the GTK event loop thread.
   */
  NotificationService::NotificationService (ctrl::BusTerm& upLink, ctrl::UiManager& uiManager)
    : BusTerm{lib::idi::EntryID<NotificationService>{}, upLink}
    , dispatch_{new UiDispatcher{[this](string msg){ displayInfo (NOTE_ERROR, msg); }}}
    , uiManager_{uiManager}
    , serviceInstance_( LUMIERA_INTERFACE_REF (lumieraorg_GuiNotification, 0,lumieraorg_GuiNotificationService))
    {
      INFO (gui, "GuiNotification Facade opened.");
    }
  
  
  NotificationService::~NotificationService() { } // emit dtors of embedded objects here...
  
  
} // namespace gui