// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'dart:async';

import '../command.dart';
import '../log.dart' as log;
import '../solver.dart';

/// Handles the `downgrade` pub command.
class DowngradeCommand extends PubCommand {
  String get name => "downgrade";
  String get description =>
      "Downgrade the current package's dependencies to oldest versions.\n\n"
      "This doesn't modify the lockfile, so it can be reset with \"pub get\".";
  String get invocation => "pub downgrade [dependencies...]";

  bool get isOffline => argResults['offline'];

  DowngradeCommand() {
    argParser.addFlag('offline',
        help: 'Use cached packages instead of accessing the network.');

    argParser.addFlag('dry-run',
        abbr: 'n',
        negatable: false,
        help: "Report what dependencies would change but don't change any.");

    argParser.addFlag('packages-dir',
        negatable: true,
        help: "Generate a packages/ directory when installing packages.");
  }

  Future run() async {
    var dryRun = argResults['dry-run'];
    await entrypoint.acquireDependencies(SolveType.DOWNGRADE,
        useLatest: argResults.rest,
        dryRun: dryRun,
        packagesDir: argResults['packages-dir']);

    if (isOffline) {
      log.warning("Warning: Downgrading when offline may not update you to "
          "the oldest versions of your dependencies.");
    }
  }
}