#pragma once

#include <SDL3/SDL_gpu.h>
#include <memory>
#include <string>
#include <unordered_map>
#include <vector>

#include "gpu_texture.hpp"

// ============================================================================
// NTSCParams — uniform buffer for NTSC shader passes (set=3, binding=0)
// Matches the layout in pass0_encode.frag and pass1_decode.frag.
// Pushed via SDL_PushGPUFragmentUniformData(cmd, 0, &ntsc, sizeof(NTSCParams)).
// ============================================================================
struct NTSCParams {
    float source_width;
    float source_height;
    float a_value;
    float b_value;
    float cc_value;
    float scan_time;
    float notch_width;
    float y_freq;
    float i_freq;
    float q_freq;
    float _pad[2];
};
static_assert(sizeof(NTSCParams) == 48, "NTSCParams must be 48 bytes");

// ============================================================================
// ShaderPass — one render pass in a multi-pass shader preset
// ============================================================================
struct ShaderPass {
    SDL_GPUGraphicsPipeline* pipeline = nullptr;
    GpuTexture*              target   = nullptr;  // null = swapchain (last pass)
};

// ============================================================================
// GpuShaderPreset — loads and owns a multi-pass shader preset from disk.
//
// Directory layout:
//   <dir>/preset.ini        — descriptor
//   <dir>/pass0_xxx.vert    — GLSL 4.50 vertex shader source
//   <dir>/pass0_xxx.frag    — GLSL 4.50 fragment shader source
//   <dir>/pass0_xxx.vert.spv — compiled SPIRV (by CMake/glslc at build time)
//   <dir>/pass0_xxx.frag.spv — compiled SPIRV
//   ...
// ============================================================================
class GpuShaderPreset {
public:
    // Load preset from directory. swapchain_fmt is the target format for the
    // last pass; intermediate passes use R16G16B16A16_FLOAT.
    bool load(SDL_GPUDevice* device,
              const std::string& dir,
              SDL_GPUTextureFormat swapchain_fmt,
              int w, int h);

    void destroy(SDL_GPUDevice* device);

    // Recreate intermediate render targets on resolution change.
    void recreateTargets(SDL_GPUDevice* device, int w, int h);

    int         passCount() const { return static_cast<int>(passes_.size()); }
    ShaderPass& pass(int i)       { return passes_[i]; }

    const std::string& name() const { return name_; }

    // Read a float parameter parsed from preset.ini (returns default_val if absent).
    float param(const std::string& key, float default_val) const;

private:
    std::vector<ShaderPass>                passes_;
    std::vector<std::unique_ptr<GpuTexture>> targets_;  // intermediate render targets
    std::string                            name_;
    std::string                            dir_;
    std::unordered_map<std::string, float> params_;
    SDL_GPUTextureFormat                   swapchain_fmt_ = SDL_GPU_TEXTUREFORMAT_R8G8B8A8_UNORM;

    // Entries read from preset.ini for each pass
    struct PassDesc {
        std::string vert_name;  // e.g. "pass0_encode.vert"
        std::string frag_name;  // e.g. "pass0_encode.frag"
    };
    std::vector<PassDesc> descs_;

    bool parseIni(const std::string& ini_path);

    // Build a full-screen-triangle pipeline from two on-disk SPV files.
    SDL_GPUGraphicsPipeline* buildPassPipeline(SDL_GPUDevice* device,
                                               const std::string& vert_spv_path,
                                               const std::string& frag_spv_path,
                                               SDL_GPUTextureFormat target_fmt);
};