#ifndef _ALU_H_
#define _ALU_H_

#include <limits.h>
#include <math.h>
#ifdef HAVE_FLOAT_H
#include <float.h>
#endif
#ifdef HAVE_IEEEFP_H
#include <ieeefp.h>
#endif

#include "alMain.h"
#include "alBuffer.h"
#include "alFilter.h"

#include "hrtf.h"
#include "align.h"


#define F_PI    (3.14159265358979323846f)
#define F_PI_2  (1.57079632679489661923f)
#define F_2PI   (6.28318530717958647692f)

#ifndef FLT_EPSILON
#define FLT_EPSILON (1.19209290e-07f)
#endif

#define DEG2RAD(x)  ((ALfloat)(x) * (F_PI/180.0f))
#define RAD2DEG(x)  ((ALfloat)(x) * (180.0f/F_PI))


#define SRC_HISTORY_BITS   (6)
#define SRC_HISTORY_LENGTH (1<<SRC_HISTORY_BITS)
#define SRC_HISTORY_MASK   (SRC_HISTORY_LENGTH-1)


#ifdef __cplusplus
extern "C" {
#endif

enum ActiveFilters {
    AF_None = 0,
    AF_LowPass = 1,
    AF_HighPass = 2,
    AF_BandPass = AF_LowPass | AF_HighPass
};

typedef struct HrtfState {
    alignas(16) ALfloat History[SRC_HISTORY_LENGTH];
    alignas(16) ALfloat Values[HRIR_LENGTH][2];
} HrtfState;

typedef struct HrtfParams {
    alignas(16) ALfloat Coeffs[HRIR_LENGTH][2];
    alignas(16) ALfloat CoeffStep[HRIR_LENGTH][2];
    ALuint Delay[2];
    ALint DelayStep[2];
} HrtfParams;

typedef struct DirectParams {
    ALfloat (*OutBuffer)[BUFFERSIZE];

    enum ActiveFilters Filters[MAX_INPUT_CHANNELS];
    ALfilterState LpFilter[MAX_INPUT_CHANNELS];
    ALfilterState HpFilter[MAX_INPUT_CHANNELS];

    /* If not 'moving', gain/coefficients are set directly without fading. */
    ALboolean Moving;
    /* Stepping counter for gain/coefficient fading. */
    ALuint Counter;
    /* History/coefficient offset. */
    ALuint Offset;

    union {
        struct {
            HrtfParams Params[MAX_INPUT_CHANNELS];
            HrtfState State[MAX_INPUT_CHANNELS];
            ALuint IrSize;
            ALfloat Gain;
            ALfloat Dir[3];
        } Hrtf;

        /* A mixing matrix. First subscript is the channel number of the input
         * data (regardless of channel configuration) and the second is the
         * channel target (eg. FrontLeft). Not used with HRTF. */
        struct {
            ALfloat Current[MAX_INPUT_CHANNELS][MaxChannels];
            ALfloat Step[MAX_INPUT_CHANNELS][MaxChannels];
            ALfloat Target[MAX_INPUT_CHANNELS][MaxChannels];
        } Gains;
    } Mix;
} DirectParams;

typedef struct SendParams {
    ALfloat (*OutBuffer)[BUFFERSIZE];

    enum ActiveFilters Filters[MAX_INPUT_CHANNELS];
    ALfilterState LpFilter[MAX_INPUT_CHANNELS];
    ALfilterState HpFilter[MAX_INPUT_CHANNELS];

    ALboolean Moving;
    ALuint Counter;

    /* Gain control, which applies to all input channels to a single (mono)
     * output buffer. */
    struct {
        ALfloat Current;
        ALfloat Step;
        ALfloat Target;
    } Gain;
} SendParams;


typedef void (*ResamplerFunc)(const ALfloat *src, ALuint frac, ALuint increment,
                              ALfloat *restrict dst, ALuint dstlen);

typedef ALvoid (*DryMixerFunc)(struct DirectParams *params,
                               const ALfloat *restrict data, ALuint srcchan,
                               ALuint OutPos, ALuint BufferSize);
typedef ALvoid (*WetMixerFunc)(struct SendParams *params,
                               const ALfloat *restrict data,
                               ALuint OutPos, ALuint BufferSize);


#define GAIN_SILENCE_THRESHOLD  (0.00001f) /* -100dB */

#define SPEEDOFSOUNDMETRESPERSEC  (343.3f)
#define AIRABSORBGAINHF           (0.99426f) /* -0.05dB */

#define FRACTIONBITS (14)
#define FRACTIONONE  (1<<FRACTIONBITS)
#define FRACTIONMASK (FRACTIONONE-1)


inline ALfloat minf(ALfloat a, ALfloat b)
{ return ((a > b) ? b : a); }
inline ALfloat maxf(ALfloat a, ALfloat b)
{ return ((a > b) ? a : b); }
inline ALfloat clampf(ALfloat val, ALfloat min, ALfloat max)
{ return minf(max, maxf(min, val)); }

inline ALdouble mind(ALdouble a, ALdouble b)
{ return ((a > b) ? b : a); }
inline ALdouble maxd(ALdouble a, ALdouble b)
{ return ((a > b) ? a : b); }
inline ALdouble clampd(ALdouble val, ALdouble min, ALdouble max)
{ return mind(max, maxd(min, val)); }

inline ALuint minu(ALuint a, ALuint b)
{ return ((a > b) ? b : a); }
inline ALuint maxu(ALuint a, ALuint b)
{ return ((a > b) ? a : b); }
inline ALuint clampu(ALuint val, ALuint min, ALuint max)
{ return minu(max, maxu(min, val)); }

inline ALint mini(ALint a, ALint b)
{ return ((a > b) ? b : a); }
inline ALint maxi(ALint a, ALint b)
{ return ((a > b) ? a : b); }
inline ALint clampi(ALint val, ALint min, ALint max)
{ return mini(max, maxi(min, val)); }

inline ALint64 mini64(ALint64 a, ALint64 b)
{ return ((a > b) ? b : a); }
inline ALint64 maxi64(ALint64 a, ALint64 b)
{ return ((a > b) ? a : b); }
inline ALint64 clampi64(ALint64 val, ALint64 min, ALint64 max)
{ return mini64(max, maxi64(min, val)); }

inline ALuint64 minu64(ALuint64 a, ALuint64 b)
{ return ((a > b) ? b : a); }
inline ALuint64 maxu64(ALuint64 a, ALuint64 b)
{ return ((a > b) ? a : b); }
inline ALuint64 clampu64(ALuint64 val, ALuint64 min, ALuint64 max)
{ return minu64(max, maxu64(min, val)); }


inline ALfloat lerp(ALfloat val1, ALfloat val2, ALfloat mu)
{
    return val1 + (val2-val1)*mu;
}
inline ALfloat cubic(ALfloat val0, ALfloat val1, ALfloat val2, ALfloat val3, ALfloat mu)
{
    ALfloat mu2 = mu*mu;
    ALfloat a0 = -0.5f*val0 +  1.5f*val1 + -1.5f*val2 +  0.5f*val3;
    ALfloat a1 =       val0 + -2.5f*val1 +  2.0f*val2 + -0.5f*val3;
    ALfloat a2 = -0.5f*val0              +  0.5f*val2;
    ALfloat a3 =                    val1;

    return a0*mu*mu2 + a1*mu2 + a2*mu + a3;
}


ALvoid aluInitPanning(ALCdevice *Device);

/**
 * ComputeAngleGains
 *
 * Sets channel gains based on a given source's angle and its half-width. The
 * angle and hwidth parameters are in radians.
 */
void ComputeAngleGains(const ALCdevice *device, ALfloat angle, ALfloat hwidth, ALfloat ingain, ALfloat gains[MaxChannels]);

/**
 * SetGains
 *
 * Helper to set the appropriate channels to the specified gain.
 */
inline void SetGains(const ALCdevice *device, ALfloat ingain, ALfloat gains[MaxChannels])
{
    ComputeAngleGains(device, 0.0f, F_PI, ingain, gains);
}


ALvoid CalcSourceParams(struct ALactivesource *src, const ALCcontext *ALContext);
ALvoid CalcNonAttnSourceParams(struct ALactivesource *src, const ALCcontext *ALContext);

ALvoid MixSource(struct ALactivesource *src, ALCdevice *Device, ALuint SamplesToDo);

ALvoid aluMixData(ALCdevice *device, ALvoid *buffer, ALsizei size);
/* Caller must lock the device. */
ALvoid aluHandleDisconnect(ALCdevice *device);

extern ALfloat ConeScale;
extern ALfloat ZScale;

#ifdef __cplusplus
}
#endif

#endif