// Copyright (c) 2017, 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 'package:analyzer/dart/analysis/results.dart';
import 'package:analyzer/file_system/file_system.dart';
import 'package:analyzer_plugin/protocol/protocol.dart';
import 'package:analyzer_plugin/protocol/protocol_common.dart'
    hide AnalysisError;
import 'package:analyzer_plugin/protocol/protocol_generated.dart';
import 'package:analyzer_plugin/src/utilities/outline/outline.dart';
import 'package:analyzer_plugin/utilities/generator.dart';

/// The information about a requested set of outline information when
/// computing outline information in a `.dart` file.
///
/// Clients may not extend, implement or mix-in this class.
abstract class DartOutlineRequest implements OutlineRequest {
  /// The analysis result for the file for which the outline is being requested.
  ResolvedUnitResult get result;
}

/// An object that [OutlineContributor]s use to record outline information.
///
/// Invocations of the [startElement] and [endElement] methods must be paired.
/// Any elements started (and ended) between a [startElement] and [endElement]
/// pair are assumed to be children of the outer pair's element and as such will
/// automatically be added as children of the outer pair's outline node.
///
/// Clients may not extend, implement or mix-in this class.
abstract class OutlineCollector {
  /// Stop recording information about the current element.
  void endElement();

  /// Start recording information about the given [element].
  void startElement(Element element, int offset, int length);
}

/// An object used to produce nodes in an outline.
///
/// Clients may implement this class when implementing plugins.
abstract class OutlineContributor {
  /// Contribute outline nodes into the given [collector].
  void computeOutline(OutlineRequest request, OutlineCollector collector);
}

/// A generator that will generate an 'analysis.outline' notification.
///
/// Clients may not extend, implement or mix-in this class.
class OutlineGenerator {
  /// The contributors to be used to generate the outline nodes.
  final List<OutlineContributor> contributors;

  /// Initialize a newly created outline generator to use the given
  /// [contributors].
  OutlineGenerator(this.contributors);

  /// Create an 'analysis.outline' notification. If any of the contributors
  /// throws an exception, also create a non-fatal 'plugin.error' notification.
  GeneratorResult generateOutlineNotification(OutlineRequest request) {
    var notifications = <Notification>[];
    var collector = OutlineCollectorImpl();
    for (var contributor in contributors) {
      try {
        contributor.computeOutline(request, collector);
      } catch (exception, stackTrace) {
        notifications.add(PluginErrorParams(
                false, exception.toString(), stackTrace.toString())
            .toNotification());
      }
    }
    notifications.add(AnalysisOutlineParams(request.path, collector.outlines)
        .toNotification());
    return GeneratorResult(null, notifications);
  }
}

/// The information about a requested set of outline information.
///
/// Clients may not extend, implement or mix-in this class.
abstract class OutlineRequest {
  /// Return the path of the file for which an outline is being requested.
  String get path;

  /// Return the resource provider associated with this request.
  ResourceProvider get resourceProvider;
}