#ifndef SOBOL_H
#define SOBOL_H

#include "Common.h"
#include <stdint.h>

#define SOBOL_BITS 32
// NOTE: May need more dimensions for later, most of commercial renderer use more than 1000 dimensions
#define SOBOL_DIMENSIONS 36

typedef enum
{
    PRNG_FILTER_U = 0,
    PRNG_FILTER_V = 1,
    PRNG_LENS_U = 2,
    PRNG_LENS_V = 3,
    PRNG_BASE_NUM = 4,

    PRNG_BSDF_U = 0,
    PRNG_BSDF_V = 1,
    PRNG_BSDF = 2,
    PRNG_LIGHT = 3,
    PRNG_LIGHT_U = 4,
    PRNG_LIGHT_V = 5,
    PRNG_LIGHT_F = 6,
    PRNG_TERMINATE = 7,
    PRNG_BOUNCE_NUM = 8
} sampling_dimension_t;

static uint32_t sobol_direction_vectors[SOBOL_DIMENSIONS][SOBOL_BITS];

// Precomputed table: s, a, and m_i's
// https://web.maths.unsw.edu.au/~fkuo/sobol/
static int s_vals[SOBOL_DIMENSIONS - 1] = {1, 2, 3, 3, 4, 4, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6,
    6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7};

static uint32_t a_vals[SOBOL_DIMENSIONS - 1] = {0, 1, 1, 2, 1, 4, 2, 4, 7, 11, 13, 14, 1, 13, 16, 19,
    22, 25, 1, 4, 7, 8, 14, 19, 21, 28, 31, 32, 37, 41, 42, 50, 55, 56, 59};

static uint32_t m_vals[SOBOL_DIMENSIONS - 1][7] = {
    {1},
    {1, 3},
    {1, 3, 1},
    {1, 1, 1},
    {1, 1, 3, 3},
    {1 ,1, 5, 13},
    {1, 1, 5, 5, 17},
    {1, 1, 5, 5, 5},
    {1, 1, 7, 11, 19},
    {1, 1, 5, 1, 1},
    {1, 1, 1, 3, 11},
    {1, 3, 5, 5, 31},
    {1, 3, 3, 9, 7, 49},
    {1, 1, 1, 15, 21, 21},
    {1, 3, 1, 13, 27, 49},
    {1, 1, 1, 15, 7, 5},
    {1, 3, 1, 15, 13, 25},
    {1, 1, 5, 5, 19, 61},
    {1, 3, 7, 11, 23, 15, 103},
    {1, 3, 7, 13, 13, 15, 69},
    {1, 1, 3, 13, 7, 35, 63},
    {1, 3, 5, 9, 1, 25, 53},
    {1, 3, 1, 13, 9, 35, 107},
    {1, 3, 1, 5, 27, 61, 31},
    {1, 1, 5, 11, 19, 41, 61},
    {1, 3, 5, 3, 3, 13, 69},
    {1, 1, 7, 13, 1, 19, 1},
    {1, 3, 7, 5, 13, 19, 59},
    {1, 1, 3, 9, 25, 29, 41},
    {1, 3, 5, 13, 23, 1, 55},
    {1, 3, 7, 3, 13, 59, 17},
    {1, 3, 1, 3, 5, 53, 69},
    {1, 1, 5, 5, 23, 33, 13},
    {1, 1, 7, 7, 1, 61, 123},
    {1, 1, 7, 9, 13, 61, 49}
};

void sobol_init();
uint16_t sobol_get_dimension(uint16_t bounce, sampling_dimension_t operation_type);
float sobol_sample(uint32_t index, uint16_t dimension);
float sobol_sample_scrambled(uint32_t index, uint16_t dimension, uint32_t scramble);

#endif // SOBOL_H