// Starfield3D.h - 3D Parallax Starfield Effect (canonical)
#pragma once

#include <SDL3/SDL.h>
#include <vector>
#include <random>
#include <array>

class Starfield3D {
public:
    Starfield3D();
    ~Starfield3D() = default;

    void init(int width, int height, int starCount = 160);
    void update(float deltaTime);
    void draw(SDL_Renderer* renderer, float offsetX = 0.0f, float offsetY = 0.0f, float alphaScale = 1.0f, bool grayscale = false);
    void resize(int width, int height);

private:
    struct Star3D {
        float x, y, z;
        float vx, vy, vz;
        float targetVx, targetVy, targetVz;
        float changeTimer;
        bool changing;
        int type;
    };

    // Helpers used by the implementation
    void createStarfield();
    void updateStar(int index);
    void setRandomDirection(Star3D& star);
    float randomFloat(float min, float max);
    int randomRange(int min, int max);
    void drawStar(SDL_Renderer* renderer, float x, float y, SDL_Color color, float alphaScale);

    std::vector<Star3D> stars;
    int width{0}, height{0};
    float centerX{0}, centerY{0};

    // Random number generator
    std::mt19937 rng;

    // Visual / behavioral constants (tweakable)
    inline static constexpr float MAX_VELOCITY = 0.5f;
    inline static constexpr float REVERSE_PROBABILITY = 0.12f;
    inline static constexpr float STAR_SPEED = 0.6f;
    inline static constexpr float MAX_DEPTH = 120.0f;
    inline static constexpr float DIRECTION_CHANGE_PROBABILITY = 0.002f;
    inline static constexpr float VELOCITY_CHANGE = 0.02f;
    inline static constexpr float MIN_Z = 0.1f;
    inline static constexpr float MAX_Z = MAX_DEPTH;
    inline static constexpr float DEPTH_FACTOR = 320.0f;

    inline static constexpr int COLOR_COUNT = 5;
    inline static const std::array<SDL_Color, COLOR_COUNT> STAR_COLORS = {
        SDL_Color{255,255,255,255},
        SDL_Color{200,200,255,255},
        SDL_Color{255,220,180,255},
        SDL_Color{180,220,255,255},
        SDL_Color{255,180,200,255}
    };
};