// Copyright (c) 2019, 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/element/element.dart';
import 'package:analyzer/dart/element/type.dart';
import 'package:dartdoc/src/element_type.dart';
import 'package:dartdoc/src/model/model.dart';
import 'package:dartdoc/src/model_utils.dart' as model_utils;
import 'package:dartdoc/src/special_elements.dart';

/// Implements the Dart 2.1 "mixin" style of mixin declarations.
class Mixin extends Class {
  Mixin(ClassElement element, Library library, PackageGraph packageGraph)
      : super(element, library, packageGraph);

  @override
  bool get isAbstract => false;

  List<Class> _inheritanceChain;

  @override
  List<Class> get inheritanceChain {
    if (_inheritanceChain == null) {
      _inheritanceChain = [];
      _inheritanceChain.add(this);

      // Mix-in interfaces come before other interfaces.
      _inheritanceChain.addAll(superclassConstraints
          .expand((ParameterizedElementType i) =>
              (i.element as Class).inheritanceChain)
          .where((Class c) =>
              c != packageGraph.specialClasses[SpecialClass.object]));

      // Interfaces need to come last, because classes in the superChain might
      // implement them even when they aren't mentioned.
      _inheritanceChain.addAll(
          interfaces.expand((e) => (e.element as Class).inheritanceChain));
    }
    return _inheritanceChain.toList(growable: false);
  }

  List<ParameterizedElementType> _superclassConstraints;

  /// Returns a list of superclass constraints for this mixin.
  Iterable<ParameterizedElementType> get superclassConstraints {
    if (_superclassConstraints == null) {
      _superclassConstraints = (element as ClassElement)
          .superclassConstraints
          .map<ParameterizedElementType>(
              (InterfaceType i) => ElementType.from(i, library, packageGraph))
          .toList();
    }
    return _superclassConstraints;
  }

  bool get hasPublicSuperclassConstraints =>
      publicSuperclassConstraints.isNotEmpty;

  Iterable<ParameterizedElementType> get publicSuperclassConstraints =>
      model_utils.filterNonPublic(superclassConstraints);

  @override
  bool get hasModifiers => super.hasModifiers || hasPublicSuperclassConstraints;

  @override
  String get fileName => "${name}-mixin.html";

  @override
  String get kind => 'mixin';
}