/**
 * @file lighting.h
 * @brief Advanced lighting system for ASCII 3D Renderer
 * @author ASCII3D Project
 * @version 2.0.0
 */

#ifndef ASCII3D_LIGHTING_H
#define ASCII3D_LIGHTING_H

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

#ifdef __cplusplus
extern "C" {
#endif

/**
 * @brief Light types
 */
typedef enum LightType {
    LIGHT_DIRECTIONAL = 0,  /* Parallel rays (sun-like) */
    LIGHT_POINT,            /* Point source with falloff */
    LIGHT_SPOT              /* Cone-shaped spotlight */
} LightType;

/**
 * @brief RGB Color structure
 */
typedef struct Color {
    float r, g, b;
} Color;

/**
 * @brief Light source structure
 */
typedef struct Light {
    LightType type;
    Vec3 position;          /* Position for point/spot lights */
    Vec3 direction;         /* Direction for directional/spot lights */
    Color color;            /* Light color */
    float intensity;        /* Light intensity multiplier */
    float falloff;          /* Attenuation for point lights */
    float spot_angle;       /* Cone angle for spotlights (radians) */
    bool enabled;
} Light;

/**
 * @brief Material properties for surfaces
 */
typedef struct Material {
    Color ambient;          /* Ambient color */
    Color diffuse;          /* Diffuse color */
    Color specular;         /* Specular highlight color */
    float shininess;        /* Specular exponent */
    float reflectivity;     /* For future use */
} Material;

/**
 * @brief Lighting system state
 */
typedef struct LightingSystem {
    Light lights[MAX_LIGHTS];
    int light_count;
    Color ambient_color;
    float ambient_intensity;
    Vec3 camera_position;
} LightingSystem;

/**
 * @brief Initialize the lighting system with default lights
 * @param system Lighting system to initialize
 */
void lighting_init(LightingSystem *system);

/**
 * @brief Add a light to the system
 * @param system Lighting system
 * @param light Light to add
 * @return Index of added light, or -1 if full
 */
int lighting_add_light(LightingSystem *system, const Light *light);

/**
 * @brief Create a directional light
 * @param direction Light direction (will be normalized)
 * @param color Light color
 * @param intensity Light intensity
 * @return Configured light structure
 */
Light lighting_create_directional(Vec3 direction, Color color, float intensity);

/**
 * @brief Create a point light
 * @param position Light position
 * @param color Light color
 * @param intensity Light intensity
 * @param falloff Attenuation factor
 * @return Configured light structure
 */
Light lighting_create_point(Vec3 position, Color color, float intensity, float falloff);

/**
 * @brief Calculate lighting at a surface point (Phong model)
 * @param system Lighting system
 * @param point Surface point position
 * @param normal Surface normal (must be normalized)
 * @param material Surface material
 * @return Final illumination value (0.0 - 1.0+)
 */
float lighting_calculate(const LightingSystem *system, Vec3 point, 
                         Vec3 normal, const Material *material);

/**
 * @brief Calculate full color lighting
 * @param system Lighting system
 * @param point Surface point position
 * @param normal Surface normal
 * @param material Surface material
 * @return Final color
 */
Color lighting_calculate_color(const LightingSystem *system, Vec3 point,
                               Vec3 normal, const Material *material);

/**
 * @brief Create default material
 * @return Default white material
 */
Material lighting_default_material(void);

/**
 * @brief Create a color
 * @param r Red (0-1)
 * @param g Green (0-1)
 * @param b Blue (0-1)
 * @return Color structure
 */
Color color_create(float r, float g, float b);

/**
 * @brief Multiply color by scalar
 */
Color color_scale(Color c, float s);

/**
 * @brief Add two colors
 */
Color color_add(Color a, Color b);

/**
 * @brief Multiply two colors component-wise
 */
Color color_multiply(Color a, Color b);

/**
 * @brief Clamp color components to 0-1 range
 */
Color color_clamp(Color c);

/**
 * @brief Convert color to grayscale intensity
 */
float color_to_intensity(Color c);

#ifdef __cplusplus
}
#endif

#endif /* ASCII3D_LIGHTING_H */