// Copyright (c) 2009-2010, Niels Martin Hansen
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
//   * Redistributions of source code must retain the above copyright notice,
//     this list of conditions and the following disclaimer.
//   * Redistributions in binary form must reproduce the above copyright notice,
//     this list of conditions and the following disclaimer in the documentation
//     and/or other materials provided with the distribution.
//   * Neither the name of the Aegisub Group nor the names of its contributors
//     may be used to endorse or promote products derived from this software
//     without specific prior written permission.
//
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// Aegisub Project http://www.aegisub.org/
//
// $Id$

/// @file audio_controller.h
/// @see audio_controller.cpp
/// @ingroup audio_ui

#pragma once

#ifndef AGI_PRE
#include <memory>
#include <vector>
#include <set>
#include <stdint.h>
#include <assert.h>
#include <wx/event.h>
#include <wx/string.h>
#include <wx/timer.h>
#include <wx/pen.h>
#include <wx/power.h>
#endif

#include <libaegisub/exception.h>
#include <libaegisub/scoped_ptr.h>
#include <libaegisub/signal.h>

class AudioPlayer;
class AudioProvider;
namespace agi { struct Context; }

// Declared below
class AudioControllerAudioEventListener;
class AudioControllerTimingEventListener;
class AudioTimingController;
class AudioMarker;
class AudioMarkerProvider;

typedef std::vector<const AudioMarker*> AudioMarkerVector;


/// @class SampleRange
/// @brief Represents an immutable range of audio samples
class SampleRange {
	int64_t _begin;
	int64_t _end;

public:
	/// @brief Constructor
	/// @param begin Index of the first sample to include in the range
	/// @param end   Index of one past the last sample to include in the range
	SampleRange(int64_t begin, int64_t end)
		: _begin(begin)
		, _end(end)
	{
		assert(end >= begin);
	}

	/// @brief Copy constructor, optionally adjusting the range
	/// @param src          The range to duplicate
	/// @param begin_adjust Number of samples to add to the start of the range
	/// @param end_adjust   Number of samples to add to the end of the range
	SampleRange(const SampleRange &src, int64_t begin_adjust = 0, int64_t end_adjust = 0)
	{
		_begin = src._begin + begin_adjust;
		_end = src._end + end_adjust;
		assert(_end >= _begin);
	}

	/// Get the number of samples in the range
	int64_t length() const { return _end - _begin; }
	/// Get the index of the first sample in the range
	int64_t begin() const { return _begin; }
	/// Get the index of one past the last sample in the range
	int64_t end() const { return _end; }

	/// Determine whether the range contains a given sample index
	bool contains(int64_t sample) const { return sample >= begin() && sample < end(); }

	/// Determine whether there is an overlap between two ranges
	bool overlaps(const SampleRange &other) const
	{
		return other.contains(_begin) || contains(other._begin);
	}
};

/// @class AudioMarkerProvider
/// @brief Abstract interface for audio marker providers
class AudioMarkerProvider {
protected:
	/// One or more of the markers provided by this object have changed
	agi::signal::Signal<> AnnounceMarkerMoved;
public:
	/// Virtual destructor, does nothing
	virtual ~AudioMarkerProvider() { }

	/// @brief Return markers in a sample range
	virtual void GetMarkers(const SampleRange &range, AudioMarkerVector &out) const = 0;

	DEFINE_SIGNAL_ADDERS(AnnounceMarkerMoved, AddMarkerMovedListener)
};

/// @class AudioLabelProvider
/// @brief Abstract interface for audio label providers
class AudioLabelProvider {
protected:
	/// One or more of the labels provided by this object have changed
	agi::signal::Signal<> AnnounceLabelChanged;
public:
	/// A label for a range of samples on the audio display
	struct AudioLabel {
		/// Text of the label
		wxString text;
		/// Range which this label applies to
		SampleRange range;
		AudioLabel(wxString const& text, SampleRange const& range) : text(text), range(range) { }
	};

	/// Virtual destructor, does nothing
	virtual ~AudioLabelProvider() { }

	/// @brief Get labels in a sample range
	/// @param range Range of samples to get labels for
	/// @param[out] out Vector which should be filled with the labels
	virtual void GetLabels(SampleRange const& range, std::vector<AudioLabel> &out) const = 0;

	DEFINE_SIGNAL_ADDERS(AnnounceLabelChanged, AddLabelChangedListener)
};

/// @class AudioController
/// @brief Manage an open audio stream and UI state for it
///
/// Keeps track of the UI interaction state of the open audio for a project,
/// i.e. what the current selection is, what movable markers are on the audio,
/// and any secondary non-movable markers that are present.
///
/// Changes in interaction are broadcast to all managed audio displays so they
/// can redraw, and the audio displays report all interactions back to the
/// controller. There is a one to many relationship between controller and
/// audio displays. There is at most one audio controller for an open
/// subtitling project.
///
/// Creates and destroys audio providers and players. This behaviour should at
/// some point be moved to a separate class, as it adds too many
/// responsibilities to this class, but at the time of writing, it would extend
/// the scope of reworking components too much.
///
/// There is not supposed to be a way to get direct access to the audio
/// providers or players owned by a controller. If some operation that isn't
/// possible in the existing design is needed, the controller should be
/// extended in some way to allow it.
class AudioController : public wxEvtHandler, public AudioMarkerProvider, public AudioLabelProvider {
	/// Project context this controller belongs to
	agi::Context *context;

	/// Slot for subtitles save signal
	agi::signal::Connection subtitle_save_slot;

	/// A new audio stream was opened (and any previously open was closed)
	agi::signal::Signal<AudioProvider*> AnnounceAudioOpen;

	/// The current audio stream was closed
	agi::signal::Signal<> AnnounceAudioClose;

	/// Playback is in progress and the current position was updated
	agi::signal::Signal<int64_t> AnnouncePlaybackPosition;

	/// Playback has stopped
	agi::signal::Signal<> AnnouncePlaybackStop;

	/// The timing controller was replaced
	agi::signal::Signal<> AnnounceTimingControllerChanged;

	/// The selected time range changed
	agi::signal::Signal<> AnnounceSelectionChanged;

	/// The audio output object
	AudioPlayer *player;

	/// The audio provider
	AudioProvider *provider;

	/// The current timing mode, if any; owned by the audio controller
	agi::scoped_ptr<AudioTimingController> timing_controller;

	/// Provide keyframe data for audio displays
	agi::scoped_ptr<AudioMarkerProvider> keyframes_marker_provider;

	/// Provider current video position data for audio display
	agi::scoped_ptr<AudioMarkerProvider> video_position_marker_provider;

	/// The URL of the currently open audio, if any
	wxString audio_url;


	enum PlaybackMode {
		PM_NotPlaying,
		PM_Range,
		PM_PrimaryRange,
		PM_ToEnd
	};
	/// The current playback mode
	PlaybackMode playback_mode;


	/// Timer used for playback position updates
	wxTimer playback_timer;

	/// Event handler for the playback timer
	void OnPlaybackTimer(wxTimerEvent &event);

	/// @brief Timing controller signals primary playback range changed
	void OnTimingControllerUpdatedPrimaryRange();

	/// @brief Timing controller signals that the rendering style ranges have changed
	void OnTimingControllerUpdatedStyleRanges();

	/// Subtitles save slot which adds the audio uri to the subtitles
	void OnSubtitlesSave();

#ifdef wxHAS_POWER_EVENTS
	/// Handle computer going into suspend mode by stopping audio and closing device
	void OnComputerSuspending(wxPowerEvent &event);
	/// Handle computer resuming from suspend by re-opening the audio device
	void OnComputerResuming(wxPowerEvent &event);
#endif

public:

	/// @brief Constructor
	AudioController(agi::Context *context);

	/// @brief Destructor
	~AudioController();


	/// @brief Open an audio stream
	/// @param url URL of the stream to open
	///
	/// The URL can either be a plain filename (with no qualifiers) or one
	/// recognised by various providers.
	void OpenAudio(const wxString &url);

	/// @brief Closes the current audio stream
	void CloseAudio();

	/// @brief Determine whether audio is currently open
	/// @return True if an audio stream is open and can be played back
	bool IsAudioOpen() const;

	/// @brief Get the URL for the current open audio stream
	/// @return The URL for the audio stream
	///
	/// The returned URL can be passed into OpenAudio() later to open the same
	/// stream again.
	wxString GetAudioURL() const;


	/// @brief Start or restart audio playback, playing a range
	/// @param range The range of audio to play back
	///
	/// The end of the played back range may be requested changed, but is not
	/// changed automatically from any other operations.
	void PlayRange(const SampleRange &range);

	/// @brief Start or restart audio playback, playing the primary playback range
	///
	/// If the primary playback range is updated during playback, the end of
	/// the active playback range will be updated to match the new selection.
	/// The playback end can not be changed in any other way.
	void PlayPrimaryRange();

	/// @brief Start or restart audio playback, playing from a point to the end of stream
	/// @param start_sample Index of the sample to start playback at
	///
	/// Playback to end cannot be converted to a range playback like range
	/// playback can, it will continue until the end is reached, it is stopped,
	/// or restarted.
	void PlayToEnd(int64_t start_sample);

	/// @brief Stop all audio playback
	void Stop();

	/// @brief Determine whether playback is ongoing
	/// @return True if audio is being played back
	bool IsPlaying();

	/// @brief Get the current playback position
	/// @return Approximate current sample index being heard by the user
	///
	/// Returns 0 if playback is stopped. The return value is only approximate.
	int64_t GetPlaybackPosition();

	/// @brief If playing, restart playback from the specified position
	/// @param new_position Sample index to restart playback from
	///
	/// This function can be used to re-synchronise audio playback to another
	/// source that might not be able to keep up with the full speed, such as
	/// video playback in high resolution or with complex subtitles.
	///
	/// This function only does something if audio is already playing.
	void ResyncPlaybackPosition(int64_t new_position);


	/// @brief Get the primary playback range
	/// @return An immutable SampleRange object
	SampleRange GetPrimaryPlaybackRange() const;

	/// @brief Get all markers inside a range
	/// @param range   The sample range to retrieve markers for
	/// @param markers Vector to fill found markers into
	void GetMarkers(const SampleRange &range, AudioMarkerVector &markers) const;

	/// @brief Get all labels inside a range
	/// @param range   The sample range to retrieve labels for
	/// @param labels Vector to fill found labels into
	void GetLabels(const SampleRange &range, std::vector<AudioLabel> &labels) const;


	/// @brief Get the playback audio volume
	/// @return The amplification factor for the audio
	double GetVolume() const;

	/// @brief Set the playback audio volume
	/// @param volume The new amplification factor for the audio
	void SetVolume(double volume);


	/// @brief Return the current audio provider
	/// @return A const pointer to the current audio provider
	const AudioProvider * GetAudioProvider() const { return provider; }


	/// @brief Return the current timing controller
	/// @return The current timing controller or 0
	AudioTimingController * GetTimingController() const { return timing_controller.get(); }

	/// @brief Change the current timing controller
	/// @param new_mode The new timing controller or 0. This may be the same
	/// object as the current timing controller, to signal that the timing
	/// controller has changed the object being timed, e.g. changed to a new
	/// dialogue line.
	void SetTimingController(AudioTimingController *new_controller);

	/// @brief Convert a count of audio samples to a time in milliseconds
	/// @param samples Sample count to convert
	/// @return The number of milliseconds equivalent to the sample-count, rounded down
	int64_t MillisecondsFromSamples(int64_t samples) const;

	/// @brief Convert a time in milliseconds to a count of audio samples
	/// @param ms Time in milliseconds to convert
	/// @return The index of the first sample that is wholly inside the millisecond
	int64_t SamplesFromMilliseconds(int64_t ms) const;

	/// @brief Save a portion of the decoded loaded audio to a wav file
	/// @param filename File to save to
	/// @param range Range of samples to save
	void SaveClip(wxString const& filename, SampleRange const& range) const;

	DEFINE_SIGNAL_ADDERS(AnnounceAudioOpen,               AddAudioOpenListener)
	DEFINE_SIGNAL_ADDERS(AnnounceAudioClose,              AddAudioCloseListener)
	DEFINE_SIGNAL_ADDERS(AnnouncePlaybackPosition,        AddPlaybackPositionListener)
	DEFINE_SIGNAL_ADDERS(AnnouncePlaybackStop,            AddPlaybackStopListener)
	DEFINE_SIGNAL_ADDERS(AnnounceTimingControllerChanged, AddTimingControllerListener)
	DEFINE_SIGNAL_ADDERS(AnnounceSelectionChanged,        AddSelectionChangedListener)
};

/// @class AudioMarker
/// @brief A marker on the audio display
class AudioMarker {
public:

	/// Describe which directions a marker has feet in
	enum FeetStyle {
		Feet_None = 0,
		Feet_Left,
		Feet_Right,
		Feet_Both // Conveniently Feet_Left|Feet_Right
	};

	/// @brief Get the marker's position
	/// @return The marker's position in samples
	virtual int64_t GetPosition() const = 0;

	/// @brief Get the marker's drawing style
	/// @return A pen object describing the marker's drawing style
	virtual wxPen GetStyle() const = 0;

	/// @brief Get the marker's feet style
	/// @return The marker's feet style
	virtual FeetStyle GetFeet() const = 0;

	/// @brief Retrieve whether this marker participates in snapping
	/// @return True if this marker may snap to other snappable markers
	///
	/// If a marker being dragged returns true from this method, and another
	/// marker which also returns true from this method is within range, the
	/// marker being dragged will be positioned at the position of the other
	/// marker if it is released while it is inside snapping range.
	virtual bool CanSnap() const = 0;
};

namespace agi {
	DEFINE_BASE_EXCEPTION(AudioControllerError, Exception);
	DEFINE_SIMPLE_EXCEPTION(AudioOpenError, AudioControllerError, "audio_controller/open_failed");
};