#pragma once

#include <QDomElement>
#include <QList>
#include <QMutex>
#include <QString>
#include <QtDebug>

#include "util/fifo.h"
#include "util/types.h"

/// Describes a group of channels, typically a pair for stereo sound in Mixxx.
class ChannelGroup {
  public:
    ChannelGroup(unsigned char channelBase, unsigned char channels);
    unsigned char getChannelBase() const;
    unsigned char getChannelCount() const;
    bool clashesWith(const ChannelGroup& other) const;

    uint hashValue() const {
        return (m_channels << 8) |
                m_channelBase;
    }
    friend uint qHash(
            const ChannelGroup& group,
            uint seed = 0) {
        return qHash(group.hashValue(), seed);
    }

    friend bool operator==(
            const ChannelGroup& lhs,
            const ChannelGroup& rhs) {
        return lhs.m_channelBase == rhs.m_channelBase &&
                lhs.m_channels == rhs.m_channels;
    }

  private:
    unsigned char m_channelBase; // base (first) channel used on device
    unsigned char m_channels; // number of channels used (s/b 2 in most cases)
};

inline bool operator!=(
        const ChannelGroup& lhs,
        const ChannelGroup& rhs) {
    return !(lhs == rhs);
}

/// Describes a path for audio to take.
///
/// TODO: Choose a better name for this class
class AudioPath {
public:
    /// Predefined types.
    ///
    /// If you add a new type here, be sure to add it to the various
    /// methods including getStringFromType, isIndexed, getTypeFromInt,
    /// channelsNeededForType (if necessary), the subclasses' getSupportedTypes
    /// (if necessary), etc.
    enum AudioPathType {
        MASTER,
        HEADPHONES,
        BOOTH,
        BUS,
        DECK,
        VINYLCONTROL,
        MICROPHONE,
        AUXILIARY,
        RECORD_BROADCAST,
        INVALID, // if this isn't last bad things will happen -bkgood
    };
    AudioPath(unsigned char channelBase, unsigned char channels);
    virtual ~AudioPath() = default;
    AudioPathType getType() const;
    ChannelGroup getChannelGroup() const;
    unsigned char getIndex() const;
    bool channelsClash(const AudioPath &other) const;
    QString getString() const;
    static QString getStringFromType(AudioPathType type);
    static QString getTrStringFromType(AudioPathType type, unsigned char index);
    static AudioPathType getTypeFromString(QString string);
    static bool isIndexed(AudioPathType type);
    static AudioPathType getTypeFromInt(int typeInt);

    /// Returns the minimum number of channels needed on a sound device for an
    /// AudioPathType.
    static unsigned char minChannelsForType(AudioPathType type);

    // Returns the maximum number of channels needed on a sound device for an
    // AudioPathType.
    static unsigned char maxChannelsForType(AudioPathType type);

    uint hashValue() const {
        // Exclude m_channelGroup from hash value!
        // See also: operator==()
        // TODO: Why??
        return (m_type << 8) |
                m_index;
    }
    friend uint qHash(
            const AudioPath& path,
            uint seed = 0) {
        return qHash(path.hashValue(), seed);
    }

    friend bool operator==(
            const AudioPath& lhs,
            const AudioPath& rhs) {
        // Exclude m_channelGroup from comparison!
        // See also: hashValue()/qHash()
        // TODO: Why??
        return lhs.m_type == rhs.m_type &&
                lhs.m_index == rhs.m_index;
    }

protected:
    virtual void setType(AudioPathType type) = 0;
    ChannelGroup m_channelGroup;
    AudioPathType m_type;
    unsigned char m_index;
};

inline bool operator!=(
        const AudioPath& lhs,
        const AudioPath& rhs) {
    return !(lhs == rhs);
}

/// A source of audio in Mixxx that is to be output to a group of
/// channels on an audio interface.
class AudioOutput : public AudioPath {
  public:
    AudioOutput(AudioPathType type, unsigned char channelBase,
                unsigned char channels,
                unsigned char index = 0);
    ~AudioOutput() override = default;
    QDomElement toXML(QDomElement *element) const;
    static AudioOutput fromXML(const QDomElement &xml);
    static QList<AudioPathType> getSupportedTypes();
    bool isHidden();
  protected:
    void setType(AudioPathType type) override;
};

// This class is required to add the buffer, without changing the hash used as ID
class AudioOutputBuffer : public AudioOutput {
  public:
    AudioOutputBuffer(const AudioOutput& out, const CSAMPLE* pBuffer)
           : AudioOutput(out),
             m_pBuffer(pBuffer) {

    };
    ~AudioOutputBuffer() override = default;
    inline const CSAMPLE* getBuffer() const { return m_pBuffer; }
  private:
    const CSAMPLE* m_pBuffer;
};

/// A source of audio at a group of channels on an audio interface
/// that is be processed in Mixxx.
class AudioInput : public AudioPath {
  public:
    AudioInput(AudioPathType type = INVALID, unsigned char channelBase = 0,
               unsigned char channels = 0, unsigned char index = 0);
    ~AudioInput() override;
    QDomElement toXML(QDomElement *element) const;
    static AudioInput fromXML(const QDomElement &xml);
    static QList<AudioPathType> getSupportedTypes();
  protected:
    void setType(AudioPathType type) override;
};

// This class is required to add the buffer, without changing the hash used as
// ID
class AudioInputBuffer : public AudioInput {
  public:
    AudioInputBuffer(const AudioInput& id, CSAMPLE* pBuffer)
            : AudioInput(id),
              m_pBuffer(pBuffer) {

    }
    ~AudioInputBuffer() override = default;
    inline CSAMPLE* getBuffer() const { return m_pBuffer; }
  private:
    CSAMPLE* m_pBuffer;
};


class AudioSource {
public:
    virtual ~AudioSource() = default;

    virtual const CSAMPLE* buffer(const AudioOutput& output) const = 0;

    /// This is called by SoundManager whenever an output is connected for this
    /// source. When this is called it is guaranteed that no callback is
    /// active.
    virtual void onOutputConnected(const AudioOutput& output) {
        Q_UNUSED(output);
    };

    /// This is called by SoundManager whenever an output is disconnected for
    /// this source. When this is called it is guaranteed that no callback is
    /// active.
    virtual void onOutputDisconnected(const AudioOutput& output) {
        Q_UNUSED(output);
    };
};

class AudioDestination {
public:
    virtual ~AudioDestination() = default;

    /// This is called by SoundManager whenever there are new samples from the
    /// configured input to be processed. This is run in the clock reference
    /// callback thread
    virtual void receiveBuffer(const AudioInput& input,
            const CSAMPLE* pBuffer,
            unsigned int iNumFrames) = 0;

    /// This is called by SoundManager whenever an input is configured for this
    /// destination. When this is called it is guaranteed that no callback is
    /// active.
    virtual void onInputConfigured(const AudioInput& input) {
        Q_UNUSED(input);
    };

    /// This is called by SoundManager whenever an input is unconfigured for this
    /// destination. When this is called it is guaranteed that no callback is
    /// active.
    virtual void onInputUnconfigured(const AudioInput& input) {
        Q_UNUSED(input);
    };
};

typedef AudioPath::AudioPathType AudioPathType;

class SoundDeviceId final {
  public:
    QString name;
    /// The "hw:X,Y" device name. Remains an empty string if not using ALSA
    /// or using a non-hw ALSA device such as "default" or "pulse".
    QString alsaHwDevice;
    int portAudioIndex;

    QString debugName() const;

    SoundDeviceId()
       : portAudioIndex(-1) {}
};

/// This must be registered with QMetaType::registerComparators for
/// QVariant::operator== to use it, which is required for QComboBox::findData to
/// work in DlgPrefSoundItem.
inline bool operator==(
        const SoundDeviceId& lhs,
        const SoundDeviceId& rhs) {
    return lhs.name == rhs.name
            && lhs.alsaHwDevice == rhs.alsaHwDevice
            && lhs.portAudioIndex == rhs.portAudioIndex;
}

inline bool operator!=(
        const SoundDeviceId& lhs,
        const SoundDeviceId& rhs) {
    return !(lhs == rhs);
}

/// There is not really a use case for this, but it is required for QMetaType::registerComparators.
inline bool operator<(const SoundDeviceId& lhs, const SoundDeviceId& rhs) {
    DEBUG_ASSERT(!"should never be invoked");
    return lhs.portAudioIndex < rhs.portAudioIndex;
}

Q_DECLARE_METATYPE(SoundDeviceId);

inline uint qHash(
        const SoundDeviceId& id,
        uint seed = 0) {
    return qHash(id.name, seed) ^
            qHash(id.alsaHwDevice, seed) ^
            qHash(id.portAudioIndex, seed);
}

inline QDebug operator<<(QDebug dbg, const SoundDeviceId& soundDeviceId) {
    return dbg << QString("SoundDeviceId(" + soundDeviceId.debugName() + ")");
}