// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#ifndef IOSAUDIOOUTPUT_H
#define IOSAUDIOOUTPUT_H

//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists purely as an
// implementation detail.  This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//

#include <private/qaudiosystem_p.h>
#include <private/qaudiostatemachine_p.h>

#if defined(Q_OS_MACOS)
# include <CoreAudio/CoreAudio.h>
#endif
#include <AudioUnit/AudioUnit.h>
#include <CoreAudio/CoreAudioTypes.h>

#include <QtCore/QIODevice>
#include <qdarwinaudiodevice_p.h>
#include <qdarwinaudiounit_p.h>
#include <qsemaphore.h>

#include "../audio/qaudioringbuffer_p.h"

QT_BEGIN_NAMESPACE

class QDarwinAudioSinkBuffer;
class QTimer;
class QCoreAudioDeviceInfo;
class CoreAudioRingBuffer;

class QDarwinAudioSinkBuffer : public QObject
{
    Q_OBJECT

public:
    QDarwinAudioSinkBuffer(int bufferSize, int maxPeriodSize, QAudioFormat const& audioFormat);
    ~QDarwinAudioSinkBuffer();

    qint64 readFrames(char *data, qint64 maxFrames);
    qint64 writeBytes(const char *data, qint64 maxSize);

    int available() const;

    bool deviceAtEnd() const;

    void reset();

    void setPrefetchDevice(QIODevice *device);

    QIODevice *prefetchDevice() const;

    void setFillingEnabled(bool enabled);

signals:
    void readyRead();

private slots:
    void fillBuffer();

private:
    bool m_deviceError = false;
    bool m_fillingEnabled = false;
    bool m_deviceAtEnd = false;
    const int m_maxPeriodSize = 0;
    const int m_bytesPerFrame = 0;
    const int m_periodTime = 0;
    QIODevice *m_device = nullptr;
    QTimer *m_fillTimer = nullptr;
    QtPrivate::QAudioRingBuffer<char> m_buffer;
};

class QDarwinAudioSinkDevice : public QIODevice
{
public:
    QDarwinAudioSinkDevice(QDarwinAudioSinkBuffer *audioBuffer, QObject *parent);

    qint64 readData(char *data, qint64 len);
    qint64 writeData(const char *data, qint64 len);

    bool isSequential() const { return true; }

private:
    QDarwinAudioSinkBuffer *m_audioBuffer;
};


class QDarwinAudioSink : public QPlatformAudioSink
{
    Q_OBJECT

public:
    QDarwinAudioSink(const QAudioDevice &device, QObject *parent);
    ~QDarwinAudioSink();

    void start(QIODevice *device);
    QIODevice *start();
    void stop();
    void reset();
    void suspend();
    void resume();
    qsizetype bytesFree() const;
    void setBufferSize(qsizetype value);
    qsizetype bufferSize() const;
    qint64 processedUSecs() const;
    QAudio::Error error() const;
    QAudio::State state() const;
    void setFormat(const QAudioFormat &format);
    QAudioFormat format() const;

    void setVolume(qreal volume);
    qreal volume() const;

private slots:
    void inputReady();
    void updateAudioDevice();
    void appStateChanged(Qt::ApplicationState state);

private:
    enum ThreadState { Running, Draining, Stopped };

    static OSStatus renderCallback(void *inRefCon,
                                    AudioUnitRenderActionFlags *ioActionFlags,
                                    const AudioTimeStamp *inTimeStamp,
                                    UInt32 inBusNumber,
                                    UInt32 inNumberFrames,
                                    AudioBufferList *ioData);

    bool open();
    void close();
    void onAudioDeviceIdle();
    void onAudioDeviceError();
    void onAudioDeviceDrained();

    QAudioDevice m_audioDevice;

    static constexpr int DEFAULT_BUFFER_SIZE = 8 * 1024;

    bool m_isOpen = false;
    int m_internalBufferSize = DEFAULT_BUFFER_SIZE;
    int m_periodSizeBytes = 0;
    qint64 m_totalFrames = 0;
    QAudioFormat m_audioFormat;
    QIODevice *m_audioIO = nullptr;
#if defined(Q_OS_MACOS)
    // TODO: The CoreAudio AudioDeviceId will change in between device connection sessions.
    // This value should be updated accordingly or be reloaded during stream setup.
    AudioDeviceID m_audioDeviceId;
#endif
    AudioUnit m_audioUnit = 0;
    AudioStreamBasicDescription m_streamFormat;
    std::unique_ptr<QDarwinAudioSinkBuffer> m_audioBuffer;
    qreal m_cachedVolume = 1.;
#if defined(Q_OS_MACOS)
    qreal m_volume = 1.;
#endif

    QAudioStateMachine m_stateMachine;
    QSemaphore m_drainSemaphore;
    AudioUnitState m_audioUnitState = AudioUnitState::Stopped;
};

QT_END_NAMESPACE

#endif // IOSAUDIOOUTPUT_H
