/*
  Copyright (C) 2002-2004 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_audioengine_h__
#define __ardour_audioengine_h__

#ifdef WAF_BUILD
#include "libardour-config.h"
#endif

#include <iostream>
#include <list>
#include <set>
#include <cmath>
#include <exception>
#include <string>

#include <glibmm/threads.h>

#include "pbd/signals.h"
#include "pbd/stacktrace.h"

#include "ardour/ardour.h"
#include "ardour/data_type.h"
#include "ardour/session_handle.h"
#include "ardour/libardour_visibility.h"
#include "ardour/types.h"
#include "ardour/chan_count.h"
#include "ardour/port_manager.h"

class MTDM;

namespace ARDOUR {

class InternalPort;
class MidiPort;
class MIDIDM;
class Port;
class Session;
class ProcessThread;
class AudioBackend;
struct AudioBackendInfo;

class LIBARDOUR_API AudioEngine : public PortManager, public SessionHandlePtr
{
  public:

	static AudioEngine* create ();

	virtual ~AudioEngine ();

	int discover_backends();
	std::vector<const AudioBackendInfo*> available_backends() const;
	std::string current_backend_name () const;
	boost::shared_ptr<AudioBackend> set_default_backend ();
	boost::shared_ptr<AudioBackend> set_backend (const std::string&, const std::string& arg1, const std::string& arg2);
	boost::shared_ptr<AudioBackend> current_backend() const { return _backend; }
	bool setup_required () const;

	ProcessThread* main_thread() const { return _main_thread; }

	/* START BACKEND PROXY API
	 *
	 * See audio_backend.h for full documentation and semantics. These wrappers
	 * just forward to a backend implementation.
	 */

	int            start (bool for_latency_measurement=false);
	int            stop (bool for_latency_measurement=false);
	int            freewheel (bool start_stop);
	float          get_dsp_load() const ;
	void           transport_start ();
	void           transport_stop ();
	TransportState transport_state ();
	void           transport_locate (framepos_t pos);
	framepos_t     transport_frame();
	framecnt_t     sample_rate () const;
	pframes_t      samples_per_cycle () const;
	int            usecs_per_cycle () const;
	size_t         raw_buffer_size (DataType t);
	framepos_t     sample_time ();
	framepos_t     sample_time_at_cycle_start ();
	pframes_t      samples_since_cycle_start ();
	bool           get_sync_offset (pframes_t& offset) const;

	std::string    get_last_backend_error () const { return _last_backend_error_string; }

	int            create_process_thread (boost::function<void()> func);
	int            join_process_threads ();
	bool           in_process_thread ();
	uint32_t       process_thread_count ();

	int            backend_reset_requested();
	void           request_backend_reset();
	void           request_device_list_update();
	void           launch_device_control_app();

	bool           is_realtime() const;
	bool           connected() const;

	// for the user which hold state_lock to check if reset operation is pending
	bool           is_reset_requested() const { return g_atomic_int_get(const_cast<gint*>(&_hw_reset_request_count)); }

	int set_device_name (const std::string&);
	int set_sample_rate (float);
	int set_buffer_size (uint32_t);
	int set_interleaved (bool yn);
	int set_input_channels (uint32_t);
	int set_output_channels (uint32_t);
	int set_systemic_input_latency (uint32_t);
	int set_systemic_output_latency (uint32_t);

	/* END BACKEND PROXY API */

	bool freewheeling() const { return _freewheeling; }
	bool running() const { return _running; }

	Glib::Threads::Mutex& process_lock() { return _process_lock; }
	Glib::Threads::RecMutex& state_lock() { return _state_lock; }

	int request_buffer_size (pframes_t samples) {
		return set_buffer_size (samples);
	}

	framecnt_t processed_frames() const { return _processed_frames; }

	void set_session (Session *);
	void remove_session (); // not a replacement for SessionHandle::session_going_away()
	Session* session() const { return _session; }

	void reconnect_session_routes (bool reconnect_inputs = true, bool reconnect_outputs = true);

	class NoBackendAvailable : public std::exception {
	    public:
		virtual const char *what() const throw() { return "could not connect to engine backend"; }
	};

	void split_cycle (pframes_t offset);

	int  reset_timebase ();

	void update_latencies ();

	/* this signal is sent for every process() cycle while freewheeling.
	   (the regular process() call to session->process() is not made)
	*/

	PBD::Signal1<void, pframes_t> Freewheel;

	PBD::Signal0<void> Xrun;

	/** this signal is emitted if the sample rate changes */
	PBD::Signal1<void, framecnt_t> SampleRateChanged;

	/** this signal is emitted if the buffer size changes */
	PBD::Signal1<void, pframes_t> BufferSizeChanged;

	/** this signal is emitted if the device cannot operate properly */
	PBD::Signal0<void> DeviceError;

	/* this signal is emitted if the device list changed */

	PBD::Signal0<void> DeviceListChanged;

	/* this signal is sent if the backend ever disconnects us */

	PBD::Signal1<void,const char*> Halted;

	/* these two are emitted when the engine itself is
	   started and stopped
	*/

	PBD::Signal0<void> Running;
	PBD::Signal0<void> Stopped;

	/* these two are emitted when a device reset is initiated/finished
	 */

	PBD::Signal0<void> DeviceResetStarted;
	PBD::Signal0<void> DeviceResetFinished;

	static AudioEngine* instance() { return _instance; }
	static void destroy();
	void died ();

	/* The backend will cause these at the appropriate time(s)
	 */
	int  process_callback (pframes_t nframes);
	int  buffer_size_change (pframes_t nframes);
	int  sample_rate_change (pframes_t nframes);
	void freewheel_callback (bool);
	void timebase_callback (TransportState state, pframes_t nframes, framepos_t pos, int new_position);
	int  sync_callback (TransportState state, framepos_t position);
	int  port_registration_callback ();
	void latency_callback (bool for_playback);
	void halted_callback (const char* reason);

	/* checks if current thread is properly set up for audio processing */
	static bool thread_initialised_for_audio_processing ();

	/* sets up the process callback thread */
	static void thread_init_callback (void *);

	/* latency measurement */

	MTDM* mtdm() { return _mtdm; }
	MIDIDM* mididm() { return _mididm; }

	int  prepare_for_latency_measurement ();
	int  start_latency_detection (bool);
	void stop_latency_detection ();
	void set_latency_input_port (const std::string&);
	void set_latency_output_port (const std::string&);
	uint32_t latency_signal_delay () const { return _latency_signal_latency; }

	enum LatencyMeasurement {
		MeasureNone,
		MeasureAudio,
		MeasureMIDI
	};

	LatencyMeasurement measuring_latency () const { return _measuring_latency; }

	/* These two are used only in builds where SILENCE_AFTER_SECONDS was
	 * set. BecameSilent will be emitted when the audioengine goes silent.
	 * reset_silence_countdown() can be used to reset the silence
	 * countdown, whose duration will be reduced to half of its previous
	 * value.
	 */

	PBD::Signal0<void> BecameSilent;
	void reset_silence_countdown ();

	void add_pending_port_deletion (Port*);

  private:
	AudioEngine ();

	static AudioEngine*       _instance;

	Glib::Threads::Mutex	   _process_lock;
	Glib::Threads::RecMutex    _state_lock;
	Glib::Threads::Cond        session_removed;
	bool                       session_remove_pending;
	frameoffset_t              session_removal_countdown;
	gain_t                     session_removal_gain;
	gain_t                     session_removal_gain_step;
	bool                      _running;
	bool                      _freewheeling;
	/// number of frames between each check for changes in monitor input
	framecnt_t                 monitor_check_interval;
	/// time of the last monitor check in frames
	framecnt_t                 last_monitor_check;
	/// the number of frames processed since start() was called
	framecnt_t                _processed_frames;
	Glib::Threads::Thread*     m_meter_thread;
	ProcessThread*            _main_thread;
	MTDM*                     _mtdm;
	MIDIDM*                   _mididm;
	LatencyMeasurement        _measuring_latency;
	PortEngine::PortHandle    _latency_input_port;
	PortEngine::PortHandle    _latency_output_port;
	framecnt_t                _latency_flush_frames;
	std::string               _latency_input_name;
	std::string               _latency_output_name;
	framecnt_t                _latency_signal_latency;
	bool                      _stopped_for_latency;
	bool                      _started_for_latency;
	bool                      _in_destructor;

	std::string               _last_backend_error_string;

	Glib::Threads::Thread*     _hw_reset_event_thread;
	gint                       _hw_reset_request_count;
	Glib::Threads::Cond        _hw_reset_condition;
	Glib::Threads::Mutex       _reset_request_lock;
	gint                       _stop_hw_reset_processing;
	Glib::Threads::Thread*     _hw_devicelist_update_thread;
	gint                       _hw_devicelist_update_count;
	Glib::Threads::Cond        _hw_devicelist_update_condition;
	Glib::Threads::Mutex       _devicelist_update_lock;
	gint                       _stop_hw_devicelist_processing;

	void start_hw_event_processing();
	void stop_hw_event_processing();
	void do_reset_backend();
	void do_devicelist_update();

	typedef std::map<std::string,AudioBackendInfo*> BackendMap;
	BackendMap _backends;
	AudioBackendInfo* backend_discover (const std::string&);
	void drop_backend ();

#ifdef SILENCE_AFTER
	framecnt_t _silence_countdown;
	uint32_t   _silence_hit_cnt;
#endif

};

} // namespace ARDOUR

#endif /* __ardour_audioengine_h__ */