#include <assets/assets_module.h>
#include <assets/loaders/shader_loader.h>
#include <assets/loaders/texture_loader.h>
#include <event/events.h>
#include <filesystem>
#include <thread>
#include <utils/logger.h>

namespace extra2d {

AssetsModule *g_assetsModule = nullptr;

AssetsModule::AssetsModule() { g_assetsModule = this; }

AssetsModule::~AssetsModule() {
  if (g_assetsModule == this) {
    g_assetsModule = nullptr;
  }
}

bool AssetsModule::init() {
  E2D_LOG_INFO("AssetsModule initializing...");

  textureLoader_ = std::make_unique<TextureLoader>();
  shaderLoader_ = std::make_unique<ShaderLoader>();

  // 监听窗口显示事件，在 OpenGL 上下文创建完成后创建默认资源
  onShowListener_ = std::make_unique<events::OnShow::Listener>();
  onShowListener_->bind([this]() { this->onGLContextReady(); });

  E2D_LOG_INFO(
      "AssetsModule initialized successfully (waiting for GL context)");
  return true;
}

void AssetsModule::onGLContextReady() {
  if (defaultResourcesCreated_) {
    return;
  }

  E2D_LOG_INFO("OpenGL context ready, creating default resources...");

  if (!createDefaultResources()) {
    E2D_LOG_ERROR("Failed to create default resources");
    return;
  }

  defaultResourcesCreated_ = true;
  E2D_LOG_INFO("Default resources created successfully");
}

void AssetsModule::shutdown() {
  E2D_LOG_INFO("AssetsModule shutting down...");

  // 释放事件监听器
  onShowListener_.reset();

  destroyDefaultResources();

  textures_.clear();
  shaders_.clear();
  materials_.clear();
  meshes_.clear();

  texturePathCache_.clear();
  shaderPathCache_.clear();

  textureLoader_.reset();
  shaderLoader_.reset();

  defaultResourcesCreated_ = false;

  E2D_LOG_INFO("AssetsModule shutdown complete");
}

AssetsModule *getAssets() { return g_assetsModule; }

//===========================================================================
// Texture 加载特化
//===========================================================================

template <>
Handle<Texture> AssetsModule::load<Texture>(const std::string &path) {
  auto it = texturePathCache_.find(path);
  if (it != texturePathCache_.end()) {
    if (textures_.isValid(it->second)) {
      return it->second;
    }
    texturePathCache_.erase(it);
  }

  if (!textureLoader_) {
    E2D_LOG_ERROR("TextureLoader not registered");
    return Handle<Texture>::invalid();
  }

  Ptr<Texture> texture = textureLoader_->load(path);
  if (!texture) {
    E2D_LOG_ERROR("Failed to load texture: {}", path);
    return Handle<Texture>::invalid();
  }

  Handle<Texture> handle = textures_.insert(texture);
  texturePathCache_[path] = handle;

  E2D_LOG_DEBUG("Loaded texture: {} -> handle index {}", path, handle.index());
  return handle;
}

template <>
Handle<Texture> AssetsModule::loadFromMemory<Texture>(const std::string &key,
                                                      const uint8_t *data,
                                                      size_t size) {
  auto it = texturePathCache_.find(key);
  if (it != texturePathCache_.end()) {
    if (textures_.isValid(it->second)) {
      return it->second;
    }
    texturePathCache_.erase(it);
  }

  if (!textureLoader_) {
    E2D_LOG_ERROR("TextureLoader not registered");
    return Handle<Texture>::invalid();
  }

  Ptr<Texture> texture = textureLoader_->loadFromMemory(data, size);
  if (!texture) {
    E2D_LOG_ERROR("Failed to load texture from memory: {}", key);
    return Handle<Texture>::invalid();
  }

  Handle<Texture> handle = textures_.insert(texture);
  texturePathCache_[key] = handle;

  return handle;
}

//===========================================================================
// Shader 加载特化
//===========================================================================

template <> Handle<Shader> AssetsModule::load<Shader>(const std::string &path) {
  auto it = shaderPathCache_.find(path);
  if (it != shaderPathCache_.end()) {
    if (shaders_.isValid(it->second)) {
      return it->second;
    }
    shaderPathCache_.erase(it);
  }

  if (!shaderLoader_) {
    E2D_LOG_ERROR("ShaderLoader not registered");
    return Handle<Shader>::invalid();
  }

  Ptr<Shader> shader = shaderLoader_->load(path);
  if (!shader) {
    E2D_LOG_ERROR("Failed to load shader: {}", path);
    return Handle<Shader>::invalid();
  }

  Handle<Shader> handle = shaders_.insert(shader);
  shaderPathCache_[path] = handle;

  E2D_LOG_DEBUG("Loaded shader: {} -> handle index {}", path, handle.index());
  return handle;
}

template <>
Handle<Shader> AssetsModule::load<Shader>(const std::string &vertPath,
                                          const std::string &fragPath) {
  std::string cacheKey = vertPath + "|" + fragPath;

  auto it = shaderPathCache_.find(cacheKey);
  if (it != shaderPathCache_.end()) {
    if (shaders_.isValid(it->second)) {
      return it->second;
    }
    shaderPathCache_.erase(it);
  }

  if (!shaderLoader_) {
    E2D_LOG_ERROR("ShaderLoader not registered");
    return Handle<Shader>::invalid();
  }

  ShaderLoader *shaderLoader = static_cast<ShaderLoader *>(shaderLoader_.get());
  Ptr<Shader> shader = shaderLoader->load(vertPath, fragPath);
  if (!shader) {
    E2D_LOG_ERROR("Failed to load shader: {} + {}", vertPath, fragPath);
    return Handle<Shader>::invalid();
  }

  Handle<Shader> handle = shaders_.insert(shader);
  shaderPathCache_[cacheKey] = handle;

  E2D_LOG_DEBUG("Loaded shader: {} + {} -> handle index {}", vertPath, fragPath,
                handle.index());
  return handle;
}

//===========================================================================
// 批量加载
//===========================================================================

template <>
std::vector<Handle<Texture>>
AssetsModule::loadDir<Texture>(const std::string &directory,
                               const std::string &pattern, bool recursive) {
  std::vector<Handle<Texture>> handles;

  try {
    std::filesystem::path dirPath(directory);
    if (!std::filesystem::exists(dirPath)) {
      E2D_LOG_WARN("Directory not found: {}", directory);
      return handles;
    }

    auto loadFile = [this, &handles](const std::filesystem::path &filePath) {
      std::string ext = filePath.extension().string();
      std::string pathStr = filePath.string();

      for (const auto &supportedExt : textureLoader_->getExtensions()) {
        if (ext == supportedExt) {
          Handle<Texture> handle = load<Texture>(pathStr);
          if (handle.isValid()) {
            handles.push_back(handle);
          }
          break;
        }
      }
    };

    if (recursive) {
      for (const auto &entry :
           std::filesystem::recursive_directory_iterator(dirPath)) {
        if (entry.is_regular_file()) {
          loadFile(entry.path());
        }
      }
    } else {
      for (const auto &entry : std::filesystem::directory_iterator(dirPath)) {
        if (entry.is_regular_file()) {
          loadFile(entry.path());
        }
      }
    }
  } catch (const std::exception &e) {
    E2D_LOG_ERROR("Error loading directory {}: {}", directory, e.what());
  }

  E2D_LOG_DEBUG("Loaded {} textures from {}", handles.size(), directory);
  return handles;
}

//===========================================================================
// 异步加载
//===========================================================================

template <>
void AssetsModule::loadAsync<Texture>(
    const std::string &path, std::function<void(Handle<Texture>)> callback) {
  std::thread([this, path, callback]() {
    Handle<Texture> handle = load<Texture>(path);
    if (callback) {
      callback(handle);
    }
  }).detach();
}

//===========================================================================
// 加载器注册
//===========================================================================

template <>
void AssetsModule::registerLoader<Texture>(
    std::unique_ptr<AssetLoader<Texture>> loader) {
  textureLoader_ = std::move(loader);
}

template <>
void AssetsModule::registerLoader<Shader>(
    std::unique_ptr<AssetLoader<Shader>> loader) {
  shaderLoader_ = std::move(loader);
}

//===========================================================================
// 默认资源
//===========================================================================

bool AssetsModule::createDefaultResources() {
  {
    Ptr<Texture> texture = makePtr<Texture>();
    uint8_t whitePixel[] = {255, 255, 255, 255};
    if (!texture->loadFromMemory(whitePixel, 1, 1, TextureFormat::RGBA8)) {
      E2D_LOG_ERROR("Failed to create default texture");
      return false;
    }
    defaultTexture_ = textures_.insert(texture);
    E2D_LOG_DEBUG("Created default texture");
  }

  {
    // 从文件加载默认着色器
    std::filesystem::path vertPath = "shader/default.vert";
    std::filesystem::path fragPath = "shader/default.frag";

    Ptr<Shader> shader = makePtr<Shader>();

    if (!std::filesystem::exists(vertPath) ||
        !std::filesystem::exists(fragPath)) {
      E2D_LOG_ERROR("Default shader files not found: {}, {}", vertPath.string(),
                    fragPath.string());
      return false;
    }

    if (!shader->loadFromFile(vertPath.string(), fragPath.string())) {
      E2D_LOG_ERROR("Failed to load default shader from files: {}, {}",
                    vertPath.string(), fragPath.string());
      return false;
    }

    defaultShader_ = shaders_.insert(shader);
    E2D_LOG_DEBUG("Loaded default shader from files: {}, {}", vertPath.string(),
                  fragPath.string());
  }

  {
    Ptr<Material> material = makePtr<Material>();
    material->setShader(getPtr(defaultShader_));
    defaultMaterial_ = materials_.insert(material);
    E2D_LOG_DEBUG("Created default material");
  }

  {
    Ptr<Mesh> mesh = Mesh::createQuad(Vec2(1.0f, 1.0f));
    if (!mesh) {
      E2D_LOG_ERROR("Failed to create default quad mesh");
      return false;
    }
    defaultQuad_ = meshes_.insert(mesh);
    E2D_LOG_DEBUG("Created default quad mesh");
  }

  return true;
}

void AssetsModule::destroyDefaultResources() {
  materials_.remove(defaultMaterial_);
  meshes_.remove(defaultQuad_);
  textures_.remove(defaultTexture_);
  shaders_.remove(defaultShader_);

  defaultMaterial_ = Handle<Material>::invalid();
  defaultQuad_ = Handle<Mesh>::invalid();
  defaultTexture_ = Handle<Texture>::invalid();
  defaultShader_ = Handle<Shader>::invalid();
}

Handle<Texture> AssetsModule::getDefaultTexture() { return defaultTexture_; }

Handle<Shader> AssetsModule::getDefaultShader() { return defaultShader_; }

Handle<Material> AssetsModule::getDefaultMaterial() { return defaultMaterial_; }

Handle<Mesh> AssetsModule::getDefaultQuad() { return defaultQuad_; }

Texture *AssetsModule::getDefaultTexturePtr() {
  return textures_.get(defaultTexture_);
}

Shader *AssetsModule::getDefaultShaderPtr() {
  return shaders_.get(defaultShader_);
}

Material *AssetsModule::getDefaultMaterialPtr() {
  return materials_.get(defaultMaterial_);
}

Mesh *AssetsModule::getDefaultQuadPtr() { return meshes_.get(defaultQuad_); }

//===========================================================================
// 热重载
//===========================================================================

void AssetsModule::enableHotReload(bool enable) { hotReloadEnabled_ = enable; }

void AssetsModule::checkForChanges() {}

//===========================================================================
// 统计
//===========================================================================

AssetsModule::Stats AssetsModule::getStats() const {
  Stats stats;
  stats.textureCount = textures_.count();
  stats.shaderCount = shaders_.count();
  stats.materialCount = materials_.count();
  stats.meshCount = meshes_.count();
  return stats;
}

} // namespace extra2d