/*
  OUTPUT-SLOT-CONNECTION.hpp  -  implementation API for concrete output slots

  Copyright (C)         Lumiera.org
    2011,               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 output-slot-connection.hpp
 ** Interface for concrete output implementations to talk to the OutputSlot frontend.
 ** The OutputSlot concept helps to decouple the render engine implementation from the details
 ** of handling external output connections. For this to work, a concrete implementation of such
 ** an external output needs to integrate with the generic OutputSlot frontend, as used by the
 ** engine. This generic frontend uses a PImpl, pointing to a ConnectionState object, which embodies
 ** the actual implementation. Moreover, this actual implementation is free to use specifically crafted
 ** OutputSlot::Connection elements to handle the ongoing output for individual channels. The latter
 ** thus becomes the central implementation side API for providing actual output capabilities.
 **
 ** @see OutputSlotProtocol_test
 ** @see diagnostic-output-slot.hpp  ////TODO
 */


#ifndef PROC_PLAY_OUTPUT_SLOT_CONNECTION_H
#define PROC_PLAY_OUTPUT_SLOT_CONNECTION_H


#include "lib/error.hpp"
#include "proc/play/output-slot.hpp"
#include "lib/handle.hpp"
//#include "lib/time/timevalue.hpp"
//#include "proc/engine/buffer-provider.hpp"
//#include "proc/play/timings.hpp"
#include "lib/iter-source.hpp"
#include "lib/iter-adapter-stl.hpp"
//#include "lib/sync.hpp"

#include <boost/noncopyable.hpp>
#include <boost/scoped_ptr.hpp>
//#include <string>
//#include <vector>
//#include <tr1/memory>


namespace proc {
namespace play {

//using ::engine::BuffHandle;
//using ::engine::BufferProvider;
//using lib::time::Time;
//using std::string;
  using lib::transform;
  using lib::iter_stl::eachElm;

//using std::vector;
//using std::tr1::shared_ptr;
  using boost::scoped_ptr;
  
  
  
  
  /** established output channel */
  class OutputSlot::Connection
    {
    public:
      virtual ~Connection();
      
      virtual void lock     (FrameID)   =0;
      virtual void transfer (FrameID)   =0;
      virtual void pushout  (FrameID)   =0;
    };
      
      
  
  
  class OutputSlot::ConnectionState
    : public OutputSlot::Allocation
    , boost::noncopyable
    {
    public:
      virtual ~ConnectionState() { }
    };
  
  
  template<class CON>
  class ConnectionStateManager
    : public OutputSlot::ConnectionState
    , public vector<CON>
    {

      typedef OutputSlot::OpenedSinks OpenedSinks;
      
      
      /* == Allocation Interface == */
      
      OpenedSinks
      getOpenedSinks()
        {
          REQUIRE (this->isActive());
          return transform (eachElm(*this), connectOutputSink);
        }
      
      bool
      isActive()
        {
          return 0 < vector<CON>::size();
        }
      
      
    public:
      ConnectionStateManager()
        {
          UNIMPLEMENTED ("immediately build up the necessary number of connections");
        }

     virtual
    ~ConnectionStateManager()
        {
          UNIMPLEMENTED ("shut down all connections");
        }
      
      virtual
      CON
      buildConnection()  =0;
      
      
    private: // Implementation details
      
      DataSink
      connectOutputSink (CON& connection)
        {
          DataSink newSink;
          newSink.activate(&connection, shutdownConnection);
          return newSink;
        }
      
      void
      shutdownConnection (CON* toClose)
        {
          UNIMPLEMENTED ("how to mark a connection as closed");
        }
    };
  
  
  
  
}} // namespace proc::play
#endif