#ifndef SKY_LIGHT_H
#define SKY_LIGHT_H

#include "Algorithm/BSDF.h"
#include "Algorithm/RayIntersection.h"
#include "Light.h"

#include <string.h>

typedef struct
{
    vec3s color;
    float intensity;
} constant_sky_data_t;

typedef struct
{
    uint32_t width;
    uint32_t height;
    texture_handle_t texture;
    float intensity;
    float total_weight;
    // Normalized discrete probability mass per texel (sum==1), indexed by [y * width + x]
    float* pdf_uv_mass;

    // CDF tables for correct runtime sampling (keeps wi/pdf consistent)
    float* cdf_x;            // size: width
    float* cdf_y_transposed; // size: width * height, layout: [x * height + y]
} hdr_sky_data_t;

sky_light_t sky_create_constant_sky(const constant_sky_data_t* data);
path_output evaluate_bsdf_const_sky(const void* data, const light_shading_context_t* context, vec3s throughput, uint32_t sample_index);

sky_light_t sky_create_hdr_sky(const texture_collection_t* textures, texture_handle_t hdri_entity, float intensity);
path_output evaluate_bsdf_hdr_sky(const void* data, const light_shading_context_t* context, vec3s throughput, uint32_t sample_index);
void hdr_sky_free(hdr_sky_data_t* data);

#endif // SKY_LIGHT_H