/* Copyright 2015 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import { fetchData } from "./display_utils.js";
import { unreachable } from "../shared/util.js";

class BaseWasmFactory {
  constructor({ baseUrl = null }) {
    if (
      (typeof PDFJSDev === "undefined" || PDFJSDev.test("TESTING")) &&
      this.constructor === BaseWasmFactory
    ) {
      unreachable("Cannot initialize BaseWasmFactory.");
    }
    this.baseUrl = baseUrl;
  }

  async fetch({ filename }) {
    if (!this.baseUrl) {
      throw new Error("Ensure that the `wasmUrl` API parameter is provided.");
    }
    if (!filename) {
      throw new Error("Wasm filename must be specified.");
    }
    const url = `${this.baseUrl}${filename}`;

    return this._fetch(url).catch(reason => {
      throw new Error(`Unable to load wasm data at: ${url}`);
    });
  }

  /**
   * @ignore
   * @returns {Promise<Uint8Array>}
   */
  async _fetch(url) {
    unreachable("Abstract method `_fetch` called.");
  }
}

class DOMWasmFactory extends BaseWasmFactory {
  /**
   * @ignore
   */
  async _fetch(url) {
    const data = await fetchData(url, /* type = */ "arraybuffer");
    return new Uint8Array(data);
  }
}

export { BaseWasmFactory, DOMWasmFactory };