// Copyright 2020 The Flutter Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file or at https://developers.google.com/open-source/licenses/bsd.

import 'dart:async';
import 'dart:io' as io;

import 'package:args/command_runner.dart';

import '../model.dart';

const _toVersionArg = 'to-version';

class RollbackCommand extends Command {
  RollbackCommand() : super() {
    argParser.addOption(_toVersionArg, mandatory: true);
  }

  @override
  String get name => 'rollback';

  @override
  String get description => 'Rolls back to a specific DevTools version.';

  @override
  Future run() async {
    final repo = DevToolsRepo.getInstance();
    print('DevTools repo at ${repo.repoPath}.');

    final tempDir =
        (await io.Directory.systemTemp.createTemp(
          'devtools-rollback',
        )).absolute;
    print('file://${tempDir.path}');
    final tarball = io.File('${tempDir.path}/devtools.tar.gz');
    final extractDir =
        await io.Directory('${tempDir.path}/extract/').absolute.create();
    final client = io.HttpClient();
    final version = argResults![_toVersionArg] as String;
    print('downloading tarball to ${tarball.path}');
    final tarballRequest = await client.getUrl(
      Uri.http(
        'storage.googleapis.com',
        'pub-packages/packages/devtools-$version.tar.gz',
      ),
    );
    final tarballResponse = await tarballRequest.close();
    await tarballResponse.pipe(tarball.openWrite());
    print('Tarball written; unzipping.');

    await io.Process.run('tar', [
      '-x',
      '-z',
      '-f',
      tarball.path.split('/').last,
      '-C',
      extractDir.path,
    ], workingDirectory: tempDir.path);
    print('file://${tempDir.path}');

    final buildDir = io.Directory('${repo.repoPath}/packages/devtools/build/');
    await buildDir.delete(recursive: true);
    await io.Directory(
      '${extractDir.path}build/',
    ).rename('${repo.repoPath}/packages/devtools/build/');

    print(
      'Build outputs from Devtools version $version checked out and moved '
      'to ${buildDir.path}',
    );
    print(
      'To complete the rollback, go to ${repo.repoPath}/packages/devtools, '
      'rev pubspec.yaml, update the changelog, unhide build/ from the '
      'packages/devtools/.gitignore file, then run pub publish.',
    );
    // TODO(djshuckerow): automatically rev pubspec.yaml and update the
    // changelog so that the user can just run pub publish from
    // packages/devtools.
  }
}