import { Loader } from "three"; // or https://cdn.jsdelivr.net/npm/three/build/three.module.js';

// WASM module of TinyUSDZ.
import initTinyUSDZNative from "./tinyusdz.js";

class FetchAssetResolver {
  constructor() {
    this.assetCache = new Map();
  }

  async resolveAsync(uri) {
    try {
      const response = await fetch(uri);
      if (!response.ok) {
        throw new Error(`Failed to fetch asset: ${uri}`);
      }
      const data = await response.arrayBuffer();
      //console.log(`Fetched asset ${uri} successfully, size: ${data.byteLength} bytes`);
      this.assetCache.set(uri, data);
      return Promise.resolve([uri, data]);
    } catch (error) {
      console.error(`Error resolving asset ${uri}:`, error);
      throw error;
    }
  }

  getAsset(uri) {
    if (this.assetCache.has(uri)) {
      return this.assetCache.get(uri);
    } else {
      console.warn(`Asset not found in cache: ${uri}`);
      return null;
    }
  }

  hasAsset(uri) {
    return this.assetCache.has(uri);
  }

  setAsset(uri, data) {
    this.assetCache.set(uri, data);
  }

  clearCache() {
    this.assetCache.clear();
  }
}

// TODO
//
// Polish API
//

class TinyUSDZLoader extends Loader {
  constructor(manager) {
    super(manager);
    this.native_ = null;
    this.assetResolver_ = null;
    this.imageCache = {};
    this.textureCache = {};
  }

  // 初始化 native 模块（直接用普通 wasm，不用压缩）
  async init(options = {}) {
    if (!this.native_) {
      console.log("Initializing TinyUSDZ native module...");
      // 直接 import，不传 wasmBinary（让 Emscripten 自己 fetch /tinyusdz.wasm）
      this.native_ = await initTinyUSDZNative();
      if (!this.native_) {
        throw new Error("Failed to initialize TinyUSDZ native module.");
      }
      console.log("Native module initialized");
    }
    return this;
  }

  // load 方法保持不变（内部会调用 init）
  load(url, onLoad, onProgress, onError) {
    const scope = this;
    const initPromise = this.native_ ? Promise.resolve() : this.init();

    initPromise
      .then(() => fetch(url))
      .then((response) => response.arrayBuffer())
      .then((usd_data) => {
        const usd_binary = new Uint8Array(usd_data);
        scope.parse(usd_binary, url, onLoad, onError);
      })
      .catch((error) => {
        console.error("TinyUSDZLoader error:", error);
        if (onError) onError(error);
      });
  }

  // parse 方法保持不变
  parse(binary, filePath, onLoad, onError) {
    if (!this.native_) {
      const err = new Error("Native module not initialized");
      console.error(err);
      if (onError) onError(err);
      return;
    }

    const usd = new this.native_.TinyUSDZLoaderNative();
    const ok = usd.loadFromBinary(binary, filePath);
    if (!ok) {
      const err = new Error("Failed to load USD from binary", { cause: usd.error() });
      if (onError) onError(err);
    } else {
      onLoad(usd);
    }
  }

  // 其他方法（如 loadAsLayer）可以保留或根据需要删减
}

export { TinyUSDZLoader, FetchAssetResolver };