pkg/analysis_server/lib/src/services/snippets/dart/flutter_stateful_widget.dart

// Copyright (c) 2022, 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:analysis_server/src/services/snippets/snippet.dart';
import 'package:analysis_server/src/services/snippets/snippet_producer.dart';
import 'package:analyzer/dart/element/element.dart';
import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';

/// Produces a [Snippet] that creates a Flutter StatefulWidget and related State
/// class.
class FlutterStatefulWidget extends FlutterSnippetProducer
    with FlutterWidgetSnippetProducerMixin {
  static const prefix = 'stful';
  static const label = 'Flutter Stateful Widget';

  late ClassElement? classStatefulWidget;
  late ClassElement? classState;
  @override
  late ClassElement? classBuildContext;
  @override
  late ClassElement? classKey;

  FlutterStatefulWidget(super.request);

  @override
  Future<Snippet> compute() async {
    final builder = ChangeBuilder(session: request.analysisSession);

    // Checked by isValid().
    final classStatefulWidget = this.classStatefulWidget!;
    final classState = this.classState!;

    await builder.addDartFileEdit(request.filePath, (builder) {
      builder.addReplacement(request.replacementRange, (builder) {
        // Write the StatefulWidget class
        builder.writeClassDeclaration(
          widgetClassName,
          nameGroupName: 'name',
          superclass: getType(classStatefulWidget),
          membersWriter: () {
            writeWidgetConstructor(builder);
            builder.writeln();
            builder.writeln();

            writeCreateStateMethod(builder);
          },
        );
        builder.writeln();
        builder.writeln();

        // Write the State class.
        builder.write('class _');
        builder.addSimpleLinkedEdit('name', widgetClassName);
        builder.write('State extends ');
        builder.writeReference(classState);
        builder.write('<');
        builder.addSimpleLinkedEdit('name', widgetClassName);
        builder.writeln('> {');
        {
          writeBuildMethod(builder);
        }
        builder.write('}');
      });
    });

    return Snippet(
      prefix,
      label,
      'Insert a Flutter StatefulWidget.',
      builder.sourceChange,
    );
  }

  @override
  Future<bool> isValid() async {
    if (!await super.isValid()) {
      return false;
    }

    if ((classStatefulWidget = await getClass('StatefulWidget')) == null ||
        (classState = await getClass('State')) == null ||
        (classBuildContext = await getClass('BuildContext')) == null ||
        (classKey = await getClass('Key')) == null) {
      return false;
    }

    return true;
  }
}