MessageManager.h

/*
 * Gamedev Framework (gf)
 * Copyright (C) 2016-2018 Julien Bernard
 *
 * This software is provided 'as-is', without any express or implied
 * warranty.  In no event will the authors be held liable for any damages
 * arising from the use of this software.
 *
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 *
 * 1. The origin of this software must not be misrepresented; you must not
 *    claim that you wrote the original software. If you use this software
 *    in a product, an acknowledgment in the product documentation would be
 *    appreciated but is not required.
 * 2. Altered source versions must be plainly marked as such, and must not be
 *    misrepresented as being the original software.
 * 3. This notice may not be removed or altered from any source distribution.
 */
#ifndef GF_MESSAGE_MANAGER_H
#define GF_MESSAGE_MANAGER_H

#include <cstdint>
#include <map>
#include <type_traits>
#include <vector>

#include "ArrayRef.h"
#include "Message.h"
#include "Portability.h"

namespace gf {
#ifndef DOXYGEN_SHOULD_SKIP_THIS
inline namespace v1 {
#endif

  using MessageHandlerId = uint64_t;

  class GF_API MessageManager {
  public:
    MessageManager();

    MessageHandlerId registerHandler(Id type, MessageHandler handler);

    template<typename E>
    MessageHandlerId registerHandler(MessageHandler handler) {
      static_assert(std::is_base_of<Message, E>::value, "E must be an Message");
      static_assert(E::type != InvalidId, "E must define its type");
      return registerHandler(E::type, handler);
    }

    template<typename R, typename T>
    MessageHandlerId registerHandler(Id type, R T::*pm, T *obj) {
      return registerHandler(type, [pm, obj](Id id, Message *msg) {
        return (obj->*pm)(id, msg);
      });
    }

    template<typename E, typename R, typename T>
    MessageHandlerId registerHandler(R T::*pm, T *obj) {
      static_assert(std::is_base_of<Message, E>::value, "E must be an Message");
      static_assert(E::type != InvalidId, "E must define its type");
      return registerHandler(E::type, [pm, obj](Id id, Message *msg) {
        return (obj->*pm)(id, msg);
      });
    }

    void removeHandler(MessageHandlerId id);

    void removeHandlers(ArrayRef<MessageHandlerId> ids) {
      for (auto id : ids) {
        removeHandler(id);
      }
    }

    void sendMessage(Id type, Message *message);

    template<typename E>
    void sendMessage(E *message) {
      static_assert(std::is_base_of<Message, E>::value, "E must be an Message");
      static_assert(E::type != InvalidId, "E must define its type");
      sendMessage(E::type, message);
    }

  private:
    struct Handler {
      MessageHandlerId id;
      MessageHandler handler;
    };

    MessageHandlerId m_currentId;
    std::map<Id, std::vector<Handler>> m_handlers;
  };

#ifndef DOXYGEN_SHOULD_SKIP_THIS
}
#endif
}

#endif // GF_MESSAGE_MANAGER_H