/**
 * Stone of Orthanc
 * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
 * Department, University Hospital of Liege, Belgium
 * Copyright (C) 2017-2018 Osimis S.A., Belgium
 *
 * This program is free software: you can redistribute it and/or
 * modify it under the terms of the GNU Affero General Public License
 * as published by the Free Software Foundation, either version 3 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
 * Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 **/


#include "gtest/gtest.h"

#include "../Framework/Messages/MessageBroker.h"
#include "../Framework/Messages/IMessage.h"
#include "../Framework/Messages/IObservable.h"
#include "../Framework/Messages/IObserver.h"
#include "../Framework/StoneEnumerations.h"


static int test1Counter = 0;
static int test2Counter = 0;
class MyFullObserver : public OrthancStone::IObserver
{

public:
  MyFullObserver(OrthancStone::MessageBroker& broker)
    : OrthancStone::IObserver(broker)
  {
    DeclareHandledMessage(OrthancStone::MessageType_Test1);
    DeclareIgnoredMessage(OrthancStone::MessageType_Test2);
  }


  void HandleMessage(OrthancStone::IObservable& from, const OrthancStone::IMessage& message) {
    switch (message.GetType())
    {
    case OrthancStone::MessageType_Test1:
      test1Counter++;
      break;
    case OrthancStone::MessageType_Test2:
      test2Counter++;
      break;
    default:
      throw OrthancStone::MessageNotDeclaredException(message.GetType());
    }
  }

};

class MyPartialObserver : public OrthancStone::IObserver
{

public:
  MyPartialObserver(OrthancStone::MessageBroker& broker)
    : OrthancStone::IObserver(broker)
  {
    DeclareHandledMessage(OrthancStone::MessageType_Test1);
    // don't declare Test2 on purpose
  }


  void HandleMessage(OrthancStone::IObservable& from, const OrthancStone::IMessage& message) {
    switch (message.GetType())
    {
    case OrthancStone::MessageType_Test1:
      test1Counter++;
      break;
    case OrthancStone::MessageType_Test2:
      test2Counter++;
      break;
    default:
      throw OrthancStone::MessageNotDeclaredException(message.GetType());
    }
  }

};


class MyObservable : public OrthancStone::IObservable
{

public:
  MyObservable(OrthancStone::MessageBroker& broker)
    : OrthancStone::IObservable(broker)
  {
    DeclareEmittableMessage(OrthancStone::MessageType_Test1);
    DeclareEmittableMessage(OrthancStone::MessageType_Test2);
  }

};


TEST(MessageBroker, NormalUsage)
{
  OrthancStone::MessageBroker broker;
  MyObservable observable(broker);

  test1Counter = 0;

  // no observers have been registered -> nothing shall happen
  observable.EmitMessage(OrthancStone::IMessage(OrthancStone::MessageType_Test1));

  ASSERT_EQ(0, test1Counter);

  // register an observer, check it is called
  MyFullObserver fullObserver(broker);
  ASSERT_NO_THROW(observable.RegisterObserver(fullObserver));

  observable.EmitMessage(OrthancStone::IMessage(OrthancStone::MessageType_Test1));

  ASSERT_EQ(1, test1Counter);

  // register an invalid observer, check it raises an exception
  MyPartialObserver partialObserver(broker);
  ASSERT_THROW(observable.RegisterObserver(partialObserver), OrthancStone::MessageNotDeclaredException);

  // check an exception is thrown when the observable emits an undeclared message
  ASSERT_THROW(observable.EmitMessage(OrthancStone::IMessage(OrthancStone::MessageType_LayerSource_GeometryReady)), OrthancStone::MessageNotDeclaredException);

  // unregister the observer, make sure nothing happens afterwards
  observable.UnregisterObserver(fullObserver);
  observable.EmitMessage(OrthancStone::IMessage(OrthancStone::MessageType_Test1));
  ASSERT_EQ(1, test1Counter);
}

TEST(MessageBroker, DeleteObserverWhileRegistered)
{
  OrthancStone::MessageBroker broker;
  MyObservable observable(broker);

  test1Counter = 0;

  {
    // register an observer, check it is called
    MyFullObserver observer(broker);
    observable.RegisterObserver(observer);

    observable.EmitMessage(OrthancStone::IMessage(OrthancStone::MessageType_Test1));

    ASSERT_EQ(1, test1Counter);
  }

  // at this point, the observer has been deleted, the handle shall not be called again (and it shall not crash !)
  observable.EmitMessage(OrthancStone::IMessage(OrthancStone::MessageType_Test1));

  ASSERT_EQ(1, test1Counter);
}