/**
 * Copyright 2020 Google Inc. All Rights Reserved.
 * 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 { promises as fs } from 'fs';

const prefix = 'as-text:';

export default function dataURLPlugin() {
  return {
    name: 'as-text-plugin',
    async resolveId(id, importer) {
      if (!id.startsWith(prefix)) return;
      const realId = id.slice(prefix.length);
      const resolveResult = await this.resolve(realId, importer);
      if (!resolveResult) throw Error(`Cannot find ${realId} from ${importer}`);
      return prefix + resolveResult.id;
    },
    async load(id) {
      if (!id.startsWith(prefix)) return;

      const realId = id.slice(prefix.length);
      this.addWatchFile(realId);

      const source = await fs.readFile(realId, { encoding: 'utf-8' });

      return `export default ${JSON.stringify(source)}`;
    },
  };
}