// Copyright (c) 2014, 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 'package:pub_semver/pub_semver.dart';

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

/// Handles the `cache add` pub command.
class CacheAddCommand extends PubCommand {
  String get name => "add";
  String get description => "Install a package.";
  String get invocation =>
      "pub cache add <package> [--version <constraint>] [--all]";
  String get docUrl => "http://dartlang.org/tools/pub/cmd/pub-cache.html";

  CacheAddCommand() {
    argParser.addFlag("all",
        help: "Install all matching versions.", negatable: false);

    argParser.addOption("version", abbr: "v", help: "Version constraint.");
  }

  Future run() async {
    // Make sure there is a package.
    if (argResults.rest.isEmpty) {
      usageException("No package to add given.");
    }

    // Don't allow extra arguments.
    if (argResults.rest.length > 1) {
      var unexpected = argResults.rest.skip(1).map((arg) => '"$arg"');
      var arguments = pluralize("argument", unexpected.length);
      usageException("Unexpected $arguments ${toSentence(unexpected)}.");
    }

    var package = argResults.rest.single;

    // Parse the version constraint, if there is one.
    var constraint = VersionConstraint.any;
    if (argResults["version"] != null) {
      try {
        constraint = new VersionConstraint.parse(argResults["version"]);
      } on FormatException catch (error) {
        usageException(error.message);
      }
    }

    // TODO(rnystrom): Support installing from git too.
    var source = cache.hosted;

    // TODO(rnystrom): Allow specifying the server.
    var ids = (await source.getVersions(cache.sources.hosted.refFor(package)))
        .where((id) => constraint.allows(id.version))
        .toList();

    if (ids.isEmpty) {
      // TODO(rnystrom): Show most recent unmatching version?
      fail("Package $package has no versions that match $constraint.");
    }

    downloadVersion(id) async {
      if (cache.contains(id)) {
        // TODO(rnystrom): Include source and description if not hosted.
        // See solve_report.dart for code to harvest.
        log.message("Already cached ${id.name} ${id.version}.");
        return null;
      }

      // Download it.
      await source.downloadToSystemCache(id);
    }

    if (argResults["all"]) {
      // Install them in ascending order.
      ids.sort((id1, id2) => id1.version.compareTo(id2.version));
      await Future.forEach(ids, downloadVersion);
    } else {
      // Pick the best matching version.
      ids.sort((id1, id2) => Version.prioritize(id1.version, id2.version));
      await downloadVersion(ids.last);
    }
  }
}