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#ifndef ENGINE_H

#define ENGINE_H

#include "spectrum.h"

#include "spectrumanalyser.h"

#include "wavfile.h"

#include <QObject>

#include <QByteArray>

#include <QBuffer>

#include <QVector>

#include <QtMultimedia/QAudioDeviceInfo>

#include <QtMultimedia/QAudioFormat>

#ifdef DUMP_CAPTURED_AUDIO

#define DUMP_DATA

#endif

#ifdef DUMP_SPECTRUM

#define DUMP_DATA

#endif

#ifdef DUMP_DATA

#include <QDir>

#endif

class QAudioInput;

class QAudioOutput;

class FrequencySpectrum;

class QFile;

/**

 * This class interfaces with the QtMultimedia audio classes, and also with

 * the SpectrumAnalyser class.  Its role is to manage the capture and playback

 * of audio data, meanwhile performing real-time analysis of the audio level

 * and frequency spectrum.

 */

class Engine : public QObject {

    Q_OBJECT

public:

    Engine(QObject *parent = 0);

    ~Engine();

    const QList<QAudioDeviceInfo>& availableAudioInputDevices() const

                                    { return m_availableAudioInputDevices; }

    const QList<QAudioDeviceInfo>& availableAudioOutputDevices() const

                                    { return m_availableAudioOutputDevices; }

    QAudio::Mode mode() const       { return m_mode; }

    QAudio::State state() const     { return m_state; }

    /**

     * \return Reference to internal audio buffer

     * \note This reference is valid for the lifetime of the Engine

     */

    const QByteArray& buffer() const    { return m_buffer; }

    /**

     * \return Current audio format

     * \note May be QAudioFormat() if engine is not initialized

     */

    const QAudioFormat& format() const  { return m_format; }

    /**

     * Stop any ongoing recording or playback, and reset to ground state.

     */

    void reset();

    /**

     * Load data from WAV file

     */

    bool loadFile(const QString &fileName);

    /**

     * Generate tone

     */

    bool generateTone(const Tone &tone);

    /**

     * Generate tone

     */

    bool generateSweptTone(qreal amplitude);

    /**

     * Initialize for recording

     */

    bool initializeRecord();

    /**

     * Position of the audio input device.

     * \return Position in microseconds.

     */

    qint64 recordPosition() const   { return m_recordPosition; }

    /**

     * RMS level of the most recently processed set of audio samples.

     * \return Level in range (0.0, 1.0)

     */

    qreal rmsLevel() const          { return m_rmsLevel; }

    /**

     * Peak level of the most recently processed set of audio samples.

     * \return Level in range (0.0, 1.0)

     */

    qreal peakLevel() const         { return m_peakLevel; }

    /**

     * Position of the audio output device.

     * \return Position in microseconds.

     */

    qint64 playPosition() const     { return m_playPosition; }

    /**

     * Length of the internal engine buffer.

     * \return Buffer length in microseconds.

     */

    qint64 bufferDuration() const;

    /**

     * Amount of data held in the buffer.

     * \return Data duration in microseconds.

     */

    qint64 dataDuration() const;

    /**

     * Returns the size of the underlying audio buffer in bytes.

     * This should be an approximation of the capture latency.

     */

    qint64 audioBufferLength() const;

    /**

     * Set window function applied to audio data before spectral analysis.

     */

    void setWindowFunction(WindowFunction type);

public slots:

    void startRecording();

    void startPlayback();

    void suspend();

    void setAudioInputDevice(const QAudioDeviceInfo &device);

    void setAudioOutputDevice(const QAudioDeviceInfo &device);

signals:

    void stateChanged(QAudio::Mode mode, QAudio::State state);

    /**

     * Informational message for non-modal display

     */

    void infoMessage(const QString &message, int durationMs);

    /**

     * Error message for modal display

     */

    void errorMessage(const QString &heading, const QString &detail);

    /**

     * Format of audio data has changed

     */

    void formatChanged(const QAudioFormat &format);

    /**

     * Length of buffer has changed.

     * \param duration Duration in microseconds

     */

    void bufferDurationChanged(qint64 duration);

    /**

     * Amount of data in buffer has changed.

     * \param duration Duration of data in microseconds

     */

    void dataDurationChanged(qint64 duration);

    /**

     * Position of the audio input device has changed.

     * \param position Position in microseconds

     */

    void recordPositionChanged(qint64 position);

    /**

     * Position of the audio output device has changed.

     * \param position Position in microseconds

     */

    void playPositionChanged(qint64 position);

    /**

     * Level changed

     * \param rmsLevel RMS level in range 0.0 - 1.0

     * \param peakLevel Peak level in range 0.0 - 1.0

     * \param numSamples Number of audio samples analysed

     */

    void levelChanged(qreal rmsLevel, qreal peakLevel, int numSamples);

    /**

     * Spectrum has changed.

     * \param position Position of start of window in microseconds

     * \param length   Length of window in microseconds

     * \param spectrum Resulting frequency spectrum

     */

    void spectrumChanged(qint64 position, qint64 length, const FrequencySpectrum &spectrum);

private slots:

    void audioNotify();

    void audioStateChanged(QAudio::State state);

    void audioDataReady();

    void spectrumChanged(const FrequencySpectrum &spectrum);

private:

    bool initialize();

    bool selectFormat();

    void stopRecording();

    void stopPlayback();

    void setState(QAudio::State state);

    void setState(QAudio::Mode mode, QAudio::State state);

    void setFormat(const QAudioFormat &format);

    void setRecordPosition(qint64 position, bool forceEmit = false);

    void setPlayPosition(qint64 position, bool forceEmit = false);

    void calculateLevel(qint64 position, qint64 length);

    void calculateSpectrum(qint64 position);

    void setLevel(qreal rmsLevel, qreal peakLevel, int numSamples);

#ifdef DUMP_DATA

    void createOutputDir();

    QString outputPath() const { return m_outputDir.path(); }

#endif

#ifdef DUMP_CAPTURED_AUDIO

    void dumpData();

#endif

private:

    QAudio::Mode        m_mode;

    QAudio::State       m_state;

    bool                m_generateTone;

    SweptTone           m_tone;

    QFile*              m_file;

    WavFile             m_wavFile;

    QAudioFormat        m_format;

    const QList<QAudioDeviceInfo> m_availableAudioInputDevices;

    QAudioDeviceInfo    m_audioInputDevice;

    QAudioInput*        m_audioInput;

    QIODevice*          m_audioInputIODevice;

    qint64              m_recordPosition;

    const QList<QAudioDeviceInfo> m_availableAudioOutputDevices;

    QAudioDeviceInfo    m_audioOutputDevice;

    QAudioOutput*       m_audioOutput;

    qint64              m_playPosition;

    QBuffer             m_audioOutputIODevice;

    QByteArray          m_buffer;

    qint64              m_dataLength;

    qreal               m_rmsLevel;

    qreal               m_peakLevel;

    int                 m_spectrumLengthBytes;

    QByteArray          m_spectrumBuffer;

    SpectrumAnalyser    m_spectrumAnalyser;

    qint64              m_spectrumPosition;

    int                 m_count;

#ifdef DUMP_DATA

    QDir                m_outputDir;

#endif

};

#endif // ENGINE_H