/*
    Copyright (C) 2000 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_tempo_h__
#define __ardour_tempo_h__

#include <list>
#include <string>
#include <vector>
#include <cmath>
#include <glibmm/threads.h>

#include "pbd/undo.h"

#include "pbd/stateful.h"
#include "pbd/statefuldestructible.h"

#include "evoral/Beats.hpp"

#include "ardour/ardour.h"

class BBTTest;
class FrameposPlusBeatsTest;
class TempoTest;
class XMLNode;

namespace ARDOUR {

class Meter;
class TempoMap;

/** Tempo, the speed at which musical time progresses (BPM). */
class LIBARDOUR_API Tempo {
  public:
	/**
	 * @param bpm Beats Per Minute
	 * @param type Note Type (default `4': quarter note)
	 */
	Tempo (double bpm, double type=4.0) // defaulting to quarter note
		: _beats_per_minute (bpm), _note_type(type) {}

	double beats_per_minute () const { return _beats_per_minute; }

	double ticks_per_minute () const { return _beats_per_minute * Timecode::BBT_Time::ticks_per_beat;}
	double note_type () const { return _note_type;}
	/** audio samples per beat
	 * @param sr samplerate
	 */
	double frames_per_beat (framecnt_t sr) const {
		return (60.0 * sr) / _beats_per_minute;
	}

  protected:
	double _beats_per_minute;
	double _note_type;
};

/** Meter, or time signature (beats per bar, and which note type is a beat). */
class LIBARDOUR_API Meter {
  public:
	Meter (double dpb, double bt)
		: _divisions_per_bar (dpb), _note_type (bt) {}

	double divisions_per_bar () const { return _divisions_per_bar; }
	double note_divisor() const { return _note_type; }

	double frames_per_bar (const Tempo&, framecnt_t sr) const;
	double frames_per_grid (const Tempo&, framecnt_t sr) const;

  protected:
	/** The number of divisions in a bar.  This is a floating point value because
	    there are musical traditions on our planet that do not limit
	    themselves to integral numbers of beats per bar.
	*/
	double _divisions_per_bar;

	/** The type of "note" that a division represents.  For example, 4.0 is
	    a quarter (crotchet) note, 8.0 is an eighth (quaver) note, etc.
	*/
	double _note_type;
};

/** A section of timeline with a certain Tempo or Meter. */
class LIBARDOUR_API MetricSection {
  public:
	MetricSection (double beat)
		: _beat (beat), _frame (0), _movable (true), _position_lock_style (PositionLockStyle::MusicTime) {}
	MetricSection (framepos_t frame)
		: _beat (0.0), _frame (frame), _movable (true), _position_lock_style (PositionLockStyle::AudioTime) {}

	virtual ~MetricSection() {}

	const double& beat () const { return _beat; }
	const double tick () const { return _beat * Timecode::BBT_Time::ticks_per_beat; }
	void set_beat (double beat) { _beat = beat;}

	framepos_t frame() const { return _frame; }
	virtual void set_frame (framepos_t f) {
		_frame = f;
	}

	void set_movable (bool yn) { _movable = yn; }
	bool movable() const { return _movable; }

	/* MeterSections are not stateful in the full sense,
	   but we do want them to control their own
	   XML state information.
	*/
	virtual XMLNode& get_state() const = 0;

	PositionLockStyle position_lock_style () const { return _position_lock_style; }
	void set_position_lock_style (PositionLockStyle ps) { _position_lock_style = ps; }

private:
	double             _beat;
	framepos_t         _frame;
	bool               _movable;
	PositionLockStyle  _position_lock_style;
};

/** A section of timeline with a certain Meter. */
class LIBARDOUR_API MeterSection : public MetricSection, public Meter {
  public:
	MeterSection (double beat, const Timecode::BBT_Time& bbt, double bpb, double note_type)
		: MetricSection (beat), Meter (bpb, note_type), _bbt (bbt) {}
	MeterSection (framepos_t frame, double bpb, double note_type)
		: MetricSection (frame), Meter (bpb, note_type), _bbt (1, 1, 0) {}
	MeterSection (const XMLNode&);

	static const std::string xml_state_node_name;

	XMLNode& get_state() const;

	void set_beat (std::pair<double, Timecode::BBT_Time>& w) {
		MetricSection::set_beat (w.first);
		_bbt = w.second;
	}

	const Timecode::BBT_Time& bbt() const { return _bbt; }
private:
	Timecode::BBT_Time _bbt;
};

/** A section of timeline with a certain Tempo. */
class LIBARDOUR_API TempoSection : public MetricSection, public Tempo {
  public:
	enum Type {
		Ramp,
		Constant,
	};

	TempoSection (const double& beat, double qpm, double note_type, Type tempo_type)
		: MetricSection (beat), Tempo (qpm, note_type), _bar_offset (-1.0), _type (tempo_type), _c_func (0.0)  {}
	TempoSection (framepos_t frame, double qpm, double note_type, Type tempo_type)
		: MetricSection (frame), Tempo (qpm, note_type), _bar_offset (-1.0), _type (tempo_type), _c_func (0.0) {}
	TempoSection (const XMLNode&);

	static const std::string xml_state_node_name;

	XMLNode& get_state() const;

	void update_bar_offset_from_bbt (const Meter&);
	void update_bbt_time_from_bar_offset (const Meter&);
	double bar_offset() const { return _bar_offset; }

	void set_type (Type type);
	Type type () const { return _type; }

	double tempo_at_frame (framepos_t frame, framecnt_t frame_rate) const;
	framepos_t frame_at_tempo (double tempo, framecnt_t frame_rate) const;

	double tick_at_frame (framepos_t frame, framecnt_t frame_rate) const;
	framepos_t frame_at_tick (double tick, framecnt_t frame_rate) const;

	double beat_at_frame (framepos_t frame, framecnt_t frame_rate) const;
	framepos_t frame_at_beat (double beat, framecnt_t frame_rate) const;

	void set_c_func_from_tempo_and_beat (double end_bpm, double end_beat, framecnt_t frame_rate);
	double compute_c_func (double end_bpm, framepos_t end_frame, framecnt_t frame_rate) const;
	double get_c_func () const { return _c_func; }
	void set_c_func (double c_func) { _c_func = c_func; }

	Timecode::BBT_Time legacy_bbt () { return _legacy_bbt; }

  private:

	framecnt_t minute_to_frame (double time, framecnt_t frame_rate) const;
	double frame_to_minute (framecnt_t frame, framecnt_t frame_rate) const;

	/*  tempo ramp functions. zero-based with time in minutes,
	 * 'tick tempo' in ticks per minute and tempo in bpm.
	 *  time relative to section start.
	 */
	double a_func (double end_tpm, double c_func) const;
	double c_func (double end_tpm, double end_time) const;

	double tick_tempo_at_time (double time) const;
	double time_at_tick_tempo (double tick_tempo) const;

	double tick_at_time (double time) const;
	double time_at_tick (double tick) const;

	double beat_at_time (double time) const;
	double time_at_beat (double beat) const;

	/* this value provides a fractional offset into the bar in which
	   the tempo section is located in. A value of 0.0 indicates that
	   it occurs on the first beat of the bar, a value of 0.5 indicates
	   that it occurs halfway through the bar and so on.

	   this enables us to keep the tempo change at the same relative
	   position within the bar if/when the meter changes.
	*/
	double _bar_offset;
	Type _type;
	double _c_func;
	Timecode::BBT_Time _legacy_bbt;
};

typedef std::list<MetricSection*> Metrics;

/** Helper class to keep track of the Meter *AND* Tempo in effect
    at a given point in time.
*/
class LIBARDOUR_API TempoMetric {
  public:
	TempoMetric (const Meter& m, const Tempo& t)
		: _meter (&m), _tempo (&t), _frame (0) {}

	void set_tempo (const Tempo& t)              { _tempo = &t; }
	void set_meter (const Meter& m)              { _meter = &m; }
	void set_frame (framepos_t f)                { _frame = f; }
	void set_beat (const double& t)              { _beat = t; }

	void set_metric (const MetricSection* section) {
		const MeterSection* meter;
		const TempoSection* tempo;
		if ((meter = dynamic_cast<const MeterSection*>(section))) {
			set_meter(*meter);
		} else if ((tempo = dynamic_cast<const TempoSection*>(section))) {
			set_tempo(*tempo);
		}

		set_frame(section->frame());
		set_beat(section->beat());
	}

	const Meter&              meter() const { return *_meter; }
	const Tempo&              tempo() const { return *_tempo; }
	framepos_t                frame() const { return _frame; }
	const double&             beat() const { return _beat; }

  private:
	const Meter*       _meter;
	const Tempo*       _tempo;
	framepos_t         _frame;
	double             _beat;
};

/** Tempo Map - mapping of timecode to musical time.
 * convert audio-samples, sample-rate to Bar/Beat/Tick, Meter/Tempo
 */
class LIBARDOUR_API TempoMap : public PBD::StatefulDestructible
{
  public:
	TempoMap (framecnt_t frame_rate);
	~TempoMap();

	/* measure-based stuff */

	enum BBTPointType {
		Bar,
		Beat,
	};

	struct BBTPoint {
		framepos_t          frame;
		const MeterSection* meter;
		const Tempo* tempo;
		uint32_t            bar;
		uint32_t            beat;

		BBTPoint (const MeterSection& m, const Tempo& t, framepos_t f,
		          uint32_t b, uint32_t e)
			: frame (f), meter (&m), tempo (&t), bar (b), beat (e) {}

		Timecode::BBT_Time bbt() const { return Timecode::BBT_Time (bar, beat, 0); }
		operator Timecode::BBT_Time() const { return bbt(); }
		operator framepos_t() const { return frame; }
		bool is_bar() const { return beat == 1; }
	};

	template<class T> void apply_with_metrics (T& obj, void (T::*method)(const Metrics&)) {
		Glib::Threads::RWLock::ReaderLock lm (lock);
		(obj.*method)(metrics);
	}

	void get_grid (std::vector<BBTPoint>&,
	               framepos_t start, framepos_t end);

	/* TEMPO- AND METER-SENSITIVE FUNCTIONS

	   bbt_time(), beat_at_frame(), frame_at_beat(), tick_at_frame(),
	   frame_at_tick(),frame_time() and bbt_duration_at()
	   are all sensitive to tempo and meter, and will give answers
	   that align with the grid formed by tempo and meter sections.

	   They SHOULD NOT be used to determine the position of events
	   whose location is canonically defined in beats.
	*/

	void bbt_time (framepos_t when, Timecode::BBT_Time&);

	double beat_at_frame (framecnt_t frame) const;
	framecnt_t frame_at_beat (double beat) const;

	framepos_t frame_time (const Timecode::BBT_Time&);
	framecnt_t bbt_duration_at (framepos_t, const Timecode::BBT_Time&, int dir);

	/* TEMPO-SENSITIVE FUNCTIONS

	   These next 4 functions will all take tempo in account and should be
	   used to determine position (and in the last case, distance in beats)
	   when tempo matters but meter does not.

	   They SHOULD be used to determine the position of events
	   whose location is canonically defined in beats.
	*/

	framepos_t framepos_plus_bbt (framepos_t pos, Timecode::BBT_Time b) const;
	framepos_t framepos_plus_beats (framepos_t, Evoral::Beats) const;
	framepos_t framepos_minus_beats (framepos_t, Evoral::Beats) const;
	Evoral::Beats framewalk_to_beats (framepos_t pos, framecnt_t distance) const;

	static const Tempo& default_tempo() { return _default_tempo; }
	static const Meter& default_meter() { return _default_meter; }

	const Tempo tempo_at (framepos_t) const;
	double frames_per_beat_at (framepos_t, framecnt_t sr) const;

	const Meter& meter_at (framepos_t) const;

	const TempoSection& tempo_section_at (framepos_t) const;
	const MeterSection& meter_section_at (framepos_t) const;

	void add_tempo (const Tempo&, double where, TempoSection::Type type);
	void add_tempo (const Tempo&, framepos_t frame, TempoSection::Type type);

	void add_meter (const Meter&, double beat, Timecode::BBT_Time where);
	void add_meter (const Meter&, framepos_t frame);

	void remove_tempo (const TempoSection&, bool send_signal);
	void remove_meter (const MeterSection&, bool send_signal);

	framepos_t compute_replacement_tempo_section (TempoSection* section, const double& tempo, const double& beat);
	void replace_tempo (const TempoSection&, const Tempo&, const double& where, TempoSection::Type type);
	void replace_tempo (const TempoSection&, const Tempo&, const framepos_t& where, TempoSection::Type type);

	void gui_set_tempo_frame (TempoSection&, framepos_t where, double beat);
	void replace_meter (const MeterSection&, const Meter&, const Timecode::BBT_Time& where);
	void replace_meter (const MeterSection&, const Meter&, const framepos_t& frame);

	framepos_t round_to_bar  (framepos_t frame, RoundMode dir);
	framepos_t round_to_beat (framepos_t frame, RoundMode dir);
	framepos_t round_to_beat_subdivision (framepos_t fr, int sub_num, RoundMode dir);

	void set_length (framepos_t frames);

	XMLNode& get_state (void);
	int set_state (const XMLNode&, int version);

	void dump (std::ostream&) const;
	void clear ();

	TempoMetric metric_at (Timecode::BBT_Time bbt) const;

	/** Return the TempoMetric at frame @p t, and point @p last to the latest
	 * metric change <= t, if it is non-NULL.
	 */
	TempoMetric metric_at (framepos_t, Metrics::const_iterator* last=NULL) const;

	Metrics::const_iterator metrics_end() { return metrics.end(); }

	void change_existing_tempo_at (framepos_t, double bpm, double note_type);
	void change_initial_tempo (double bpm, double note_type);

	void insert_time (framepos_t, framecnt_t);
	bool remove_time (framepos_t where, framecnt_t amount);  //returns true if anything was moved

	int n_tempos () const;
	int n_meters () const;

	framecnt_t frame_rate () const { return _frame_rate; }

	PBD::Signal0<void> MetricPositionChanged;

	double bbt_to_beats (Timecode::BBT_Time bbt);
	Timecode::BBT_Time beats_to_bbt (double beats);

private:
	double bbt_to_beats_locked (Timecode::BBT_Time bbt);
	Timecode::BBT_Time beats_to_bbt_locked (double beats);
	double beat_at_frame_locked (framecnt_t frame) const;
	framecnt_t frame_at_beat_locked (double beat) const;
	double tick_at_frame_locked (framecnt_t frame) const;
	framecnt_t frame_at_tick_locked (double tick) const;
	framepos_t frame_time_locked (const Timecode::BBT_Time&);

	friend class ::BBTTest;
	friend class ::FrameposPlusBeatsTest;
	friend class ::TempoTest;

	static Tempo    _default_tempo;
	static Meter    _default_meter;

	Metrics                       metrics;
	framecnt_t                    _frame_rate;
	mutable Glib::Threads::RWLock lock;

	void recompute_map (bool reassign_tempo_bbt, framepos_t end = -1);

	framepos_t round_to_type (framepos_t fr, RoundMode dir, BBTPointType);

	const MeterSection& first_meter() const;
	MeterSection&       first_meter();
	const TempoSection& first_tempo() const;
	TempoSection&       first_tempo();

	void do_insert (MetricSection* section);

	void add_tempo_locked (const Tempo&, double where, bool recompute, TempoSection::Type type);
	void add_tempo_locked (const Tempo&, framepos_t frame, bool recompute, TempoSection::Type type);

	void add_meter_locked (const Meter&, double beat, Timecode::BBT_Time where, bool recompute);
	void add_meter_locked (const Meter&, framepos_t frame, bool recompute);

	bool remove_tempo_locked (const TempoSection&);
	bool remove_meter_locked (const MeterSection&);

};

}; /* namespace ARDOUR */

std::ostream& operator<< (std::ostream&, const ARDOUR::Meter&);
std::ostream& operator<< (std::ostream&, const ARDOUR::Tempo&);
std::ostream& operator<< (std::ostream&, const ARDOUR::MetricSection&);

#endif /* __ardour_tempo_h__ */