generateForAnnotatedElement method

@override Future<String> generateForAnnotatedElement(Element element, ConstantReader annotation, BuildStep buildStep)

Implement to return source code to generate for element.

This method is invoked based on finding elements annotated with an instance of T. The annotation is provided as a ConstantReader.

Supported return values include a single String or multiple String instances within an Iterable or Stream. It is also valid to return a Future of String, Iterable, or Stream.

Implementations should return null when no content is generated. Empty or whitespace-only String instances are also ignored.

Implementation

@override
Future<String> generateForAnnotatedElement(
  Element element,
  ConstantReader annotation,
  BuildStep buildStep,
) async {
  if (element.isPrivate) {
    throw InvalidGenerationSourceError(
      'Widgetbook annotations cannot be applied to private elements',
      element: element,
    );
  }

  final locales = <String>[];

  final node = await buildStep.resolver.astNodeFor(element);
  if (node != null) {
    final entities = node.childEntities.toList();
    if (entities[0] is SimpleIdentifier &&
        entities[1] is Token &&
        entities[2] is ListLiteral) {
      final listLiteral = entities[2] as ListLiteral;

      // TODO this is likely the most flaky code that has ever been written
      // check the following cases
      // - Locale('en')
      // - const Locale('en')
      // - Locale('en', 'US')
      // - const Locale('en', 'US')
      // - additional methods, e.g. Locale.fromString('...') and similar stuff
      // Maybe it's best to just use a regex
      final localeDefinitions = listLiteral.elements.toList();
      for (final localeDefinition in localeDefinitions) {
        // If expression starts WITHOUT const e.g. Local('en'), this will
        // be called
        if (localeDefinition is MethodInvocation) {
          final stringLiteral =
              localeDefinition.argumentList.arguments.first as StringLiteral;
          final value = stringLiteral.stringValue!;
          locales.add(value);
        }
        // If expression starts WITH const e.g. const Local('en'), this will
        // be called
        if (localeDefinition is InstanceCreationExpression) {
          final stringLiteral =
              localeDefinition.argumentList.arguments.first as StringLiteral;
          final value = stringLiteral.stringValue!;
          locales.add(value);
        }
      }
    }
  }

  final data = WidgetbookLocalesData(
    name: element.name!,
    importStatement: element.importStatement,
    dependencies: [],
    locales: locales,
  );

  return [data].toJson();
}