/**
 * Copyright 2025 Google LLC
 *
 * 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
 *
 *      https://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 {Storage} from '@google-cloud/storage';

export async function getFileFromGCS(filePath: string): Promise<string> {
  const parsed = new URL(filePath);
  const bucket = parsed.hostname;
  const filename = parsed.pathname.substring(1);

  return new Promise((resolve, reject) => {
    const storage = new Storage();
    let fileContents = Buffer.from('');
    storage
      .bucket(bucket)
      .file(filename)
      .createReadStream()
      .on('error', err => {
        reject(
          `Failed to download '${filePath}' file content from GCS: ` + err
        );
      })
      .on('data', chunk => {
        fileContents = Buffer.concat([fileContents, chunk]);
      })
      .on('end', () => {
        const content = fileContents.toString('utf8');
        resolve(content);
      });
  });
}