// Copyright (c) 2018, 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 'dart:convert';

import 'package:path/path.dart' as p;

import '../entrypoint.dart';
import '../io.dart';
import '../validator.dart';

/// A validator that validates a package's changelog file.
class ChangelogValidator extends Validator {
  ChangelogValidator(Entrypoint entrypoint) : super(entrypoint);

  @override
  Future validate() {
    return Future.sync(() {
      final changelog = entrypoint.root.changelogPath;

      if (changelog == null) {
        warnings.add('Please add a`CHANGELOG.md` to your package. '
            'See https://dart.dev/tools/pub/publishing#important-files.');
        return;
      }

      if (p.basename(changelog) != 'CHANGELOG.md') {
        warnings.add('Please consider renaming $changelog to `CHANGELOG.md`. '
            'See https://dart.dev/tools/pub/publishing#important-files.');
      }

      var bytes = readBinaryFile(changelog);
      String contents;

      try {
        // utf8.decode doesn't allow invalid UTF-8.
        contents = utf8.decode(bytes);
      } on FormatException catch (_) {
        warnings.add('$changelog contains invalid UTF-8.\n'
            'This will cause it to be displayed incorrectly on '
            'the Pub site (https://pub.dev).');
      }

      if (contents == null) {
        // Failed to decode contents, so there's nothing else to check.
        return;
      }

      final version = entrypoint.root.pubspec.version.toString();

      if (!contents.contains(version)) {
        warnings.add("$changelog doesn't mention current version ($version).\n"
            'Consider updating it with notes on this version prior to '
            'publication.');
      }
    });
  }
}