/*
  Copyright 2018 Google LLC

  Use of this source code is governed by an MIT-style
  license that can be found in the LICENSE file or at
  https://opensource.org/licenses/MIT.
*/

import fse from 'fs-extra';
import upath from 'upath';

import {WorkboxPackageJSON} from '../types';
import {errors} from './errors';

// Used to filter the libraries to copy based on our package.json dependencies.
const WORKBOX_PREFIX = 'workbox-';

// The directory within each package containing the final bundles.
const BUILD_DIR = 'build';

/**
 * This copies over a set of runtime libraries used by Workbox into a
 * local directory, which should be deployed alongside your service worker file.
 *
 * As an alternative to deploying these local copies, you could instead use
 * Workbox from its official CDN URL.
 *
 * This method is exposed for the benefit of developers using
 * {@link workbox-build.injectManifest} who would
 * prefer not to use the CDN copies of Workbox. Developers using
 * {@link workbox-build.generateSW} don't need to
 * explicitly call this method.
 *
 * @param {string} destDirectory The path to the parent directory under which
 * the new directory of libraries will be created.
 * @return {Promise<string>} The name of the newly created directory.
 *
 * @alias workbox-build.copyWorkboxLibraries
 */
export async function copyWorkboxLibraries(
  destDirectory: string,
): Promise<string> {
  // eslint-disable-next-line  @typescript-eslint/no-unsafe-assignment
  const thisPkg: WorkboxPackageJSON = require('../../package.json');
  // Use the version string from workbox-build in the name of the parent
  // directory. This should be safe, because lerna will bump workbox-build's
  // pkg.version whenever one of the dependent libraries gets bumped, and we
  // care about versioning the dependent libraries.
  const workboxDirectoryName = `workbox-v${
    thisPkg.version ? thisPkg.version : ''
  }`;
  const workboxDirectoryPath = upath.join(destDirectory, workboxDirectoryName);
  await fse.ensureDir(workboxDirectoryPath);

  const copyPromises: Array<Promise<void>> = [];
  const librariesToCopy = Object.keys(thisPkg.dependencies || {}).filter(
    (dependency) => dependency.startsWith(WORKBOX_PREFIX),
  );

  for (const library of librariesToCopy) {
    // Get the path to the package on the user's filesystem by require-ing
    // the package's `package.json` file via the node resolution algorithm.
    const libraryPath = upath.dirname(
      require.resolve(`${library}/package.json`),
    );

    const buildPath = upath.join(libraryPath, BUILD_DIR);

    // fse.copy() copies all the files in a directory, not the directory itself.
    // See https://github.com/jprichardson/node-fs-extra/blob/master/docs/copy.md#copysrc-dest-options-callback
    copyPromises.push(fse.copy(buildPath, workboxDirectoryPath));
  }

  try {
    await Promise.all(copyPromises);
    return workboxDirectoryName;
  } catch (error) {
    throw Error(
      `${errors['unable-to-copy-workbox-libraries']} ${
        error instanceof Error ? error.toString() : ''
      }`,
    );
  }
}