#ifndef ASCII3D_LIGHTING_H
#define ASCII3D_LIGHTING_H

#include "config.h"
#include "vec3.h"
#include <stdbool.h>

#ifdef __cplusplus
extern "C" {
#endif

typedef enum LightType {
  LIGHT_DIRECTIONAL = 0,
  LIGHT_POINT,
  LIGHT_SPOT
} LightType;

typedef struct Color {
  float r, g, b;
} Color;

typedef struct Light {
  LightType type;
  Vec3 position;
  Vec3 direction;
  Color color;
  float intensity;
  float falloff;
  float spot_angle;
  bool enabled;
} Light;

// PBR surface components
typedef struct Material {
  Color ambient;
  Color diffuse;
  Color specular;
  float shininess;
  float reflectivity;
} Material;

// Encapsulates the entire render context's virtual ecosystem
typedef struct LightingSystem {
  Light lights[MAX_LIGHTS];
  int light_count;
  Color ambient_color;
  float ambient_intensity;
  Vec3 camera_position;
} LightingSystem;

// Instantiates default 3-point portrait lighting scheme
void lighting_init(LightingSystem *system);

// Registers a new light emitter into the system context
int lighting_add_light(LightingSystem *system, const Light *light);

Light lighting_create_directional(Vec3 direction, Color color, float intensity);
Light lighting_create_point(Vec3 position, Color color, float intensity,
                            float falloff);

// Computes monochrome or RGB shading based on surface interactions
float lighting_calculate(const LightingSystem *system, Vec3 point, Vec3 normal,
                         const Material *material);
Color lighting_calculate_color(const LightingSystem *system, Vec3 point,
                               Vec3 normal, const Material *material);

Material lighting_default_material(void);

// Floating point color combinators
Color color_create(float r, float g, float b);
Color color_scale(Color c, float s);
Color color_add(Color a, Color b);
Color color_multiply(Color a, Color b);
Color color_clamp(Color c);
float color_to_intensity(Color c);

#ifdef __cplusplus
}
#endif

#endif