#include "shader_manager.hpp"

#include <SDL3/SDL_log.h>
#include <filesystem>
#include <algorithm>

namespace fs = std::filesystem;

void ShaderManager::scan(const std::string& root_dir) {
    root_dir_ = root_dir;
    names_.clear();
    dirs_.clear();

    std::error_code ec;
    for (const auto& entry : fs::directory_iterator(root_dir, ec)) {
        if (!entry.is_directory()) continue;
        fs::path ini = entry.path() / "preset.ini";
        if (!fs::exists(ini)) continue;

        std::string preset_name = entry.path().filename().string();
        names_.push_back(preset_name);
        dirs_[preset_name] = entry.path().string();
    }

    if (ec) {
        SDL_Log("ShaderManager: scan error on %s: %s", root_dir.c_str(), ec.message().c_str());
    }

    std::sort(names_.begin(), names_.end());
    SDL_Log("ShaderManager: found %d preset(s) in %s", (int)names_.size(), root_dir.c_str());
}

GpuShaderPreset* ShaderManager::load(SDL_GPUDevice* device,
                                      const std::string& name,
                                      SDL_GPUTextureFormat swapchain_fmt,
                                      int w, int h) {
    auto it = loaded_.find(name);
    if (it != loaded_.end()) return it->second.get();

    auto dir_it = dirs_.find(name);
    if (dir_it == dirs_.end()) {
        SDL_Log("ShaderManager: preset '%s' not found", name.c_str());
        return nullptr;
    }

    auto preset = std::make_unique<GpuShaderPreset>();
    if (!preset->load(device, dir_it->second, swapchain_fmt, w, h)) {
        SDL_Log("ShaderManager: failed to load preset '%s'", name.c_str());
        return nullptr;
    }

    GpuShaderPreset* raw = preset.get();
    loaded_[name] = std::move(preset);
    return raw;
}

void ShaderManager::onResize(SDL_GPUDevice* device, SDL_GPUTextureFormat /*swapchain_fmt*/, int w, int h) {
    for (auto& [name, preset] : loaded_) {
        preset->recreateTargets(device, w, h);
    }
}

void ShaderManager::destroyAll(SDL_GPUDevice* device) {
    for (auto& [name, preset] : loaded_) {
        preset->destroy(device);
    }
    loaded_.clear();
}