#ifndef AL_MAIN_H
#define AL_MAIN_H

#include <algorithm>
#include <array>
#include <atomic>
#include <chrono>
#include <cstdint>
#include <cstddef>
#include <memory>
#include <mutex>
#include <string>
#include <utility>

#include "AL/al.h"
#include "AL/alc.h"
#include "AL/alext.h"

#include "albyte.h"
#include "almalloc.h"
#include "alnumeric.h"
#include "alspan.h"
#include "ambidefs.h"
#include "atomic.h"
#include "hrtf.h"
#include "inprogext.h"
#include "vector.h"

class BFormatDec;
struct ALbuffer;
struct ALeffect;
struct ALfilter;
struct BackendBase;
struct Compressor;
struct EffectState;
struct FrontStablizer;
struct Uhj2Encoder;
struct bs2b;


#ifndef UNUSED
#if defined(__cplusplus)
#define UNUSED(x)
#elif defined(__GNUC__)
#define UNUSED(x) UNUSED_##x __attribute__((unused))
#elif defined(__LCLINT__)
#define UNUSED(x) /*@unused@*/ x
#else
#define UNUSED(x) x
#endif
#endif


#if defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__)
#define IS_LITTLE_ENDIAN (__BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__)
#else
static const union {
    ALuint u;
    ALubyte b[sizeof(ALuint)];
} EndianTest = { 1 };
#define IS_LITTLE_ENDIAN (EndianTest.b[0] == 1)
#endif


#define MIN_OUTPUT_RATE      8000
#define DEFAULT_OUTPUT_RATE  44100
#define DEFAULT_UPDATE_SIZE  882 /* 20ms */
#define DEFAULT_NUM_UPDATES  3


enum Channel {
    FrontLeft = 0,
    FrontRight,
    FrontCenter,
    LFE,
    BackLeft,
    BackRight,
    BackCenter,
    SideLeft,
    SideRight,

    UpperFrontLeft,
    UpperFrontRight,
    UpperBackLeft,
    UpperBackRight,
    LowerFrontLeft,
    LowerFrontRight,
    LowerBackLeft,
    LowerBackRight,

    Aux0,
    Aux1,
    Aux2,
    Aux3,
    Aux4,
    Aux5,
    Aux6,
    Aux7,
    Aux8,
    Aux9,
    Aux10,
    Aux11,
    Aux12,
    Aux13,
    Aux14,
    Aux15,

    MaxChannels
};


/* Device formats */
enum DevFmtType : ALenum {
    DevFmtByte   = ALC_BYTE_SOFT,
    DevFmtUByte  = ALC_UNSIGNED_BYTE_SOFT,
    DevFmtShort  = ALC_SHORT_SOFT,
    DevFmtUShort = ALC_UNSIGNED_SHORT_SOFT,
    DevFmtInt    = ALC_INT_SOFT,
    DevFmtUInt   = ALC_UNSIGNED_INT_SOFT,
    DevFmtFloat  = ALC_FLOAT_SOFT,

    DevFmtTypeDefault = DevFmtFloat
};
enum DevFmtChannels : ALenum {
    DevFmtMono   = ALC_MONO_SOFT,
    DevFmtStereo = ALC_STEREO_SOFT,
    DevFmtQuad   = ALC_QUAD_SOFT,
    DevFmtX51    = ALC_5POINT1_SOFT,
    DevFmtX61    = ALC_6POINT1_SOFT,
    DevFmtX71    = ALC_7POINT1_SOFT,
    DevFmtAmbi3D = ALC_BFORMAT3D_SOFT,

    /* Similar to 5.1, except using rear channels instead of sides */
    DevFmtX51Rear = 0x70000000,

    DevFmtChannelsDefault = DevFmtStereo
};
#define MAX_OUTPUT_CHANNELS  (16)

/* DevFmtType traits, providing the type, etc given a DevFmtType. */
template<DevFmtType T>
struct DevFmtTypeTraits { };

template<>
struct DevFmtTypeTraits<DevFmtByte> { using Type = ALbyte; };
template<>
struct DevFmtTypeTraits<DevFmtUByte> { using Type = ALubyte; };
template<>
struct DevFmtTypeTraits<DevFmtShort> { using Type = ALshort; };
template<>
struct DevFmtTypeTraits<DevFmtUShort> { using Type = ALushort; };
template<>
struct DevFmtTypeTraits<DevFmtInt> { using Type = ALint; };
template<>
struct DevFmtTypeTraits<DevFmtUInt> { using Type = ALuint; };
template<>
struct DevFmtTypeTraits<DevFmtFloat> { using Type = ALfloat; };


ALsizei BytesFromDevFmt(DevFmtType type) noexcept;
ALsizei ChannelsFromDevFmt(DevFmtChannels chans, ALsizei ambiorder) noexcept;
inline ALsizei FrameSizeFromDevFmt(DevFmtChannels chans, DevFmtType type, ALsizei ambiorder) noexcept
{ return ChannelsFromDevFmt(chans, ambiorder) * BytesFromDevFmt(type); }

enum class AmbiLayout {
    FuMa = ALC_FUMA_SOFT, /* FuMa channel order */
    ACN = ALC_ACN_SOFT,   /* ACN channel order */

    Default = ACN
};

enum class AmbiNorm {
    FuMa = ALC_FUMA_SOFT, /* FuMa normalization */
    SN3D = ALC_SN3D_SOFT, /* SN3D normalization */
    N3D = ALC_N3D_SOFT,   /* N3D normalization */

    Default = SN3D
};


enum DeviceType {
    Playback,
    Capture,
    Loopback
};


enum RenderMode {
    NormalRender,
    StereoPair,
    HrtfRender
};


struct BufferSubList {
    uint64_t FreeMask{~0_u64};
    ALbuffer *Buffers{nullptr}; /* 64 */

    BufferSubList() noexcept = default;
    BufferSubList(const BufferSubList&) = delete;
    BufferSubList(BufferSubList&& rhs) noexcept : FreeMask{rhs.FreeMask}, Buffers{rhs.Buffers}
    { rhs.FreeMask = ~0_u64; rhs.Buffers = nullptr; }
    ~BufferSubList();

    BufferSubList& operator=(const BufferSubList&) = delete;
    BufferSubList& operator=(BufferSubList&& rhs) noexcept
    { std::swap(FreeMask, rhs.FreeMask); std::swap(Buffers, rhs.Buffers); return *this; }
};

struct EffectSubList {
    uint64_t FreeMask{~0_u64};
    ALeffect *Effects{nullptr}; /* 64 */

    EffectSubList() noexcept = default;
    EffectSubList(const EffectSubList&) = delete;
    EffectSubList(EffectSubList&& rhs) noexcept : FreeMask{rhs.FreeMask}, Effects{rhs.Effects}
    { rhs.FreeMask = ~0_u64; rhs.Effects = nullptr; }
    ~EffectSubList();

    EffectSubList& operator=(const EffectSubList&) = delete;
    EffectSubList& operator=(EffectSubList&& rhs) noexcept
    { std::swap(FreeMask, rhs.FreeMask); std::swap(Effects, rhs.Effects); return *this; }
};

struct FilterSubList {
    uint64_t FreeMask{~0_u64};
    ALfilter *Filters{nullptr}; /* 64 */

    FilterSubList() noexcept = default;
    FilterSubList(const FilterSubList&) = delete;
    FilterSubList(FilterSubList&& rhs) noexcept : FreeMask{rhs.FreeMask}, Filters{rhs.Filters}
    { rhs.FreeMask = ~0_u64; rhs.Filters = nullptr; }
    ~FilterSubList();

    FilterSubList& operator=(const FilterSubList&) = delete;
    FilterSubList& operator=(FilterSubList&& rhs) noexcept
    { std::swap(FreeMask, rhs.FreeMask); std::swap(Filters, rhs.Filters); return *this; }
};


/* Maximum delay in samples for speaker distance compensation. */
#define MAX_DELAY_LENGTH 1024

class DistanceComp {
public:
    struct DistData {
        ALfloat Gain{1.0f};
        ALsizei Length{0}; /* Valid range is [0...MAX_DELAY_LENGTH). */
        ALfloat *Buffer{nullptr};
    };

private:
    std::array<DistData,MAX_OUTPUT_CHANNELS> mChannels;
    al::vector<ALfloat,16> mSamples;

public:
    void setSampleCount(size_t new_size) { mSamples.resize(new_size); }
    void clear() noexcept
    {
        for(auto &chan : mChannels)
        {
            chan.Gain = 1.0f;
            chan.Length = 0;
            chan.Buffer = nullptr;
        }
        using SampleVecT = decltype(mSamples);
        SampleVecT{}.swap(mSamples);
    }

    ALfloat *getSamples() noexcept { return mSamples.data(); }

    al::span<DistData,MAX_OUTPUT_CHANNELS> as_span() { return mChannels; }
};

struct BFChannelConfig {
    ALfloat Scale;
    ALsizei Index;
};

/* Size for temporary storage of buffer data, in ALfloats. Larger values need
 * more memory, while smaller values may need more iterations. The value needs
 * to be a sensible size, however, as it constrains the max stepping value used
 * for mixing, as well as the maximum number of samples per mixing iteration.
 */
#define BUFFERSIZE 1024

using FloatBufferLine = std::array<float,BUFFERSIZE>;

/* Maximum number of samples to pad on either end of a buffer for resampling.
 * Note that both the beginning and end need padding!
 */
#define MAX_RESAMPLE_PADDING 24


struct MixParams {
    /* Coefficient channel mapping for mixing to the buffer. */
    std::array<BFChannelConfig,MAX_OUTPUT_CHANNELS> AmbiMap{};

    al::span<FloatBufferLine> Buffer;
};

struct RealMixParams {
    std::array<ALint,MaxChannels> ChannelIndex{};

    al::span<FloatBufferLine> Buffer;
};

using POSTPROCESS = void(*)(ALCdevice *device, const ALsizei SamplesToDo);

enum {
    // Frequency was requested by the app or config file
    FrequencyRequest,
    // Channel configuration was requested by the config file
    ChannelsRequest,
    // Sample type was requested by the config file
    SampleTypeRequest,

    // Specifies if the DSP is paused at user request
    DevicePaused,
    // Specifies if the device is currently running
    DeviceRunning,

    DeviceFlagsCount
};

struct ALCdevice {
    RefCount ref{1u};

    std::atomic<bool> Connected{true};
    const DeviceType Type{};

    ALuint Frequency{};
    ALuint UpdateSize{};
    ALuint BufferSize{};

    DevFmtChannels FmtChans{};
    DevFmtType     FmtType{};
    ALboolean IsHeadphones{AL_FALSE};
    ALsizei mAmbiOrder{0};
    /* For DevFmtAmbi* output only, specifies the channel order and
     * normalization.
     */
    AmbiLayout mAmbiLayout{AmbiLayout::Default};
    AmbiNorm   mAmbiScale{AmbiNorm::Default};

    ALCenum LimiterState{ALC_DONT_CARE_SOFT};

    std::string DeviceName;

    // Device flags
    al::bitfield<DeviceFlagsCount> Flags{};

    std::string HrtfName;
    al::vector<EnumeratedHrtf> HrtfList;
    ALCenum HrtfStatus{ALC_FALSE};

    std::atomic<ALCenum> LastError{ALC_NO_ERROR};

    // Maximum number of sources that can be created
    ALuint SourcesMax{};
    // Maximum number of slots that can be created
    ALuint AuxiliaryEffectSlotMax{};

    ALCuint NumMonoSources{};
    ALCuint NumStereoSources{};
    ALsizei NumAuxSends{};

    // Map of Buffers for this device
    std::mutex BufferLock;
    al::vector<BufferSubList> BufferList;

    // Map of Effects for this device
    std::mutex EffectLock;
    al::vector<EffectSubList> EffectList;

    // Map of Filters for this device
    std::mutex FilterLock;
    al::vector<FilterSubList> FilterList;

    /* Rendering mode. */
    RenderMode mRenderMode{NormalRender};

    /* The average speaker distance as determined by the ambdec configuration,
     * HRTF data set, or the NFC-HOA reference delay. Only used for NFC.
     */
    ALfloat AvgSpeakerDist{0.0f};

    ALuint SamplesDone{0u};
    std::chrono::nanoseconds ClockBase{0};
    std::chrono::nanoseconds FixedLatency{0};

    /* Temp storage used for mixer processing. */
    alignas(16) ALfloat SourceData[BUFFERSIZE + MAX_RESAMPLE_PADDING*2];
    alignas(16) ALfloat ResampledData[BUFFERSIZE];
    alignas(16) ALfloat FilteredData[BUFFERSIZE];
    union {
        alignas(16) ALfloat HrtfSourceData[BUFFERSIZE + HRTF_HISTORY_LENGTH];
        alignas(16) ALfloat NfcSampleData[BUFFERSIZE];
    };
    alignas(16) float2 HrtfAccumData[BUFFERSIZE + HRIR_LENGTH];

    /* Mixing buffer used by the Dry mix and Real output. */
    al::vector<FloatBufferLine, 16> MixBuffer;

    /* The "dry" path corresponds to the main output. */
    MixParams Dry;
    ALuint NumChannelsPerOrder[MAX_AMBI_ORDER+1]{};

    /* "Real" output, which will be written to the device buffer. May alias the
     * dry buffer.
     */
    RealMixParams RealOut;

    /* HRTF state and info */
    std::unique_ptr<DirectHrtfState> mHrtfState;
    HrtfEntry *mHrtf{nullptr};

    /* Ambisonic-to-UHJ encoder */
    std::unique_ptr<Uhj2Encoder> Uhj_Encoder;

    /* Ambisonic decoder for speakers */
    std::unique_ptr<BFormatDec> AmbiDecoder;

    /* Stereo-to-binaural filter */
    std::unique_ptr<bs2b> Bs2b;

    POSTPROCESS PostProcess{};

    std::unique_ptr<FrontStablizer> Stablizer;

    std::unique_ptr<Compressor> Limiter;

    /* Delay buffers used to compensate for speaker distances. */
    DistanceComp ChannelDelay;

    /* Dithering control. */
    ALfloat DitherDepth{0.0f};
    ALuint DitherSeed{0u};

    /* Running count of the mixer invocations, in 31.1 fixed point. This
     * actually increments *twice* when mixing, first at the start and then at
     * the end, so the bottom bit indicates if the device is currently mixing
     * and the upper bits indicates how many mixes have been done.
     */
    RefCount MixCount{0u};

    // Contexts created on this device
    std::atomic<al::FlexArray<ALCcontext*>*> mContexts{nullptr};

    /* This lock protects the device state (format, update size, etc) from
     * being from being changed in multiple threads, or being accessed while
     * being changed. It's also used to serialize calls to the backend.
     */
    std::mutex StateLock;
    std::unique_ptr<BackendBase> Backend;


    ALCdevice(DeviceType type);
    ALCdevice(const ALCdevice&) = delete;
    ALCdevice& operator=(const ALCdevice&) = delete;
    ~ALCdevice();

    ALsizei bytesFromFmt() const noexcept { return BytesFromDevFmt(FmtType); }
    ALsizei channelsFromFmt() const noexcept { return ChannelsFromDevFmt(FmtChans, mAmbiOrder); }
    ALsizei frameSizeFromFmt() const noexcept { return bytesFromFmt() * channelsFromFmt(); }

    DEF_NEWDEL(ALCdevice)
};

/* Must be less than 15 characters (16 including terminating null) for
 * compatibility with pthread_setname_np limitations. */
#define MIXER_THREAD_NAME "alsoft-mixer"

#define RECORD_THREAD_NAME "alsoft-record"


enum {
    /* End event thread processing. */
    EventType_KillThread = 0,

    /* User event types. */
    EventType_SourceStateChange = 1<<0,
    EventType_BufferCompleted   = 1<<1,
    EventType_Error             = 1<<2,
    EventType_Performance       = 1<<3,
    EventType_Deprecated        = 1<<4,
    EventType_Disconnected      = 1<<5,

    /* Internal events. */
    EventType_ReleaseEffectState = 65536,
};

struct AsyncEvent {
    unsigned int EnumType{0u};
    union {
        char dummy;
        struct {
            ALuint id;
            ALenum state;
        } srcstate;
        struct {
            ALuint id;
            ALsizei count;
        } bufcomp;
        struct {
            ALenum type;
            ALuint id;
            ALuint param;
            ALchar msg[1008];
        } user;
        EffectState *mEffectState;
    } u{};

    AsyncEvent() noexcept = default;
    constexpr AsyncEvent(unsigned int type) noexcept : EnumType{type} { }
};


void AllocateVoices(ALCcontext *context, size_t num_voices);


extern ALint RTPrioLevel;
void SetRTPriority(void);

void SetDefaultChannelOrder(ALCdevice *device);
void SetDefaultWFXChannelOrder(ALCdevice *device);

const ALCchar *DevFmtTypeString(DevFmtType type) noexcept;
const ALCchar *DevFmtChannelsString(DevFmtChannels chans) noexcept;

/**
 * GetChannelIdxByName
 *
 * Returns the index for the given channel name (e.g. FrontCenter), or -1 if it
 * doesn't exist.
 */
inline ALint GetChannelIdxByName(const RealMixParams &real, Channel chan) noexcept
{ return real.ChannelIndex[chan]; }


void StartEventThrd(ALCcontext *ctx);
void StopEventThrd(ALCcontext *ctx);


al::vector<std::string> SearchDataFiles(const char *match, const char *subdir);

#endif