#pragma once

#include "../shader_backend.h"

#ifdef __APPLE__

#import <Metal/Metal.h>
#import <QuartzCore/CAMetalLayer.h>

namespace Rendering {

/**
 * @brief Backend de shaders usando Metal para macOS
 *
 * Implementa el renderizado de shaders usando Metal API nativo de Apple:
 * - MTLDevice para acceso a GPU
 * - MTLRenderPipelineState para configuración del pipeline
 * - MTLCommandQueue para enviar comandos a GPU
 * - MSL (Metal Shading Language) para shaders
 */
class MetalShader : public ShaderBackend {
public:
    MetalShader() = default;
    ~MetalShader() override;

    bool init(SDL_Window* window,
             SDL_Texture* texture,
             const std::string& vertex_source,
             const std::string& fragment_source) override;

    void render() override;
    void setTextureSize(float width, float height) override;
    void cleanup() override;
    bool isHardwareAccelerated() const override { return is_initialized_; }

private:
    // Funciones auxiliares
    bool createMetalDevice();
    bool compileShaders(const std::string& vertex_source,
                       const std::string& fragment_source);
    bool createPipeline();
    bool createBuffers();
    id<MTLTexture> getMetalTexture(SDL_Texture* texture);

    // Estado SDL
    SDL_Window* window_ = nullptr;
    SDL_Renderer* renderer_ = nullptr;
    SDL_Texture* back_buffer_ = nullptr;

    // Estado Metal
    id<MTLDevice> device_ = nil;                          // GPU device
    id<MTLCommandQueue> command_queue_ = nil;             // Cola de comandos
    id<MTLRenderPipelineState> pipeline_state_ = nil;     // Estado del pipeline
    id<MTLBuffer> vertex_buffer_ = nil;                   // Buffer de vértices
    id<MTLBuffer> index_buffer_ = nil;                    // Buffer de índices
    id<MTLBuffer> uniforms_buffer_ = nil;                 // Buffer de uniforms
    CAMetalLayer* metal_layer_ = nil;                     // Layer de Metal

    // Uniforms
    struct Uniforms {
        float textureSize[2];  // width, height
    } uniforms_;

    // Tamaños
    int window_width_ = 0;
    int window_height_ = 0;
    float texture_width_ = 0.0f;
    float texture_height_ = 0.0f;

    // Estado
    bool is_initialized_ = false;
};

} // namespace Rendering

#endif // __APPLE__