/*
    Copyright (C) 2009-2010 Paul Davis

    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.

*/

#ifndef __ardour_processor_h__
#define __ardour_processor_h__

#include <vector>
#include <string>
#include <exception>

#include "pbd/statefuldestructible.h"


#include "ardour/ardour.h"
#include "ardour/automatable_controls.h"
#include "ardour/buffer_set.h"
#include "ardour/latent.h"
#include "ardour/session_object.h"
#include "ardour/types.h"

class XMLNode;

namespace ARDOUR {

class Session;
class Route;

/* A mixer strip element - plugin, send, meter, etc.
 */
class Processor : public SessionObject, public AutomatableControls, public Latent
{
  public:
	static const std::string state_node_name;

	Processor(Session&, const std::string& name);
	Processor(Session&, const XMLNode& node);

	virtual ~Processor() { }

	virtual std::string display_name() const { return SessionObject::name(); }

	virtual bool display_to_user() const { return _display_to_user; }
	virtual void set_display_to_user (bool);

	bool active () const { return _pending_active; }

	bool get_next_ab_is_active () const { return _next_ab_is_active; }
	void set_next_ab_is_active (bool yn) { _next_ab_is_active = yn; }

	virtual nframes_t signal_latency() const { return 0; }

	virtual void transport_stopped (sframes_t /*frame*/) {}

	virtual void set_block_size (nframes_t /*nframes*/) {}

	/** @param result_required true if, on return from this method, bufs is required to contain valid data;
	 *  if false, the method need not bother writing to bufs if it doesn't want to.
	 */  
	virtual void run (BufferSet& /*bufs*/, sframes_t /*start_frame*/, sframes_t /*end_frame*/, nframes_t /*nframes*/, bool result_required) {}
	virtual void silence (nframes_t /*nframes*/) {}

	virtual void activate ()   { _pending_active = true; ActiveChanged(); }
	virtual void deactivate () { _pending_active = false; ActiveChanged(); }

	virtual bool configure_io (ChanCount in, ChanCount out);

	/* Derived classes should override these, or processor appears as an in-place pass-through */

	virtual bool can_support_io_configuration (const ChanCount& in, ChanCount& out) const = 0;
	virtual ChanCount input_streams () const { return _configured_input; }
	virtual ChanCount output_streams() const { return _configured_output; }

	/* note: derived classes should implement state(), NOT get_state(), to allow
	   us to merge C++ inheritance and XML lack-of-inheritance reasonably
	   smoothly.
	 */

	virtual XMLNode& state (bool full);
	XMLNode& get_state (void);
	int set_state (const XMLNode&, int version);
	
	void *get_gui () const { return _gui; }
	void  set_gui (void *p) { _gui = p; }

	static PBD::Signal1<void,Processor*> ProcessorCreated;

	PBD::Signal0<void>                     ActiveChanged;
	PBD::Signal2<void,ChanCount,ChanCount> ConfigurationChanged;

protected:
	int       _pending_active;
	bool      _active;
	bool      _next_ab_is_active;
	bool      _configured;
	ChanCount _configured_input;
	ChanCount _configured_output;
	void*     _gui;  /* generic, we don't know or care what this is */
	bool        _display_to_user;

private:
	int set_state_2X (const XMLNode&, int version);
};

} // namespace ARDOUR

#endif /* __ardour_processor_h__ */