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 {
  Element enviedEl = element;
  if (enviedEl is! ClassElement) {
    throw InvalidGenerationSourceError(
      '`@Envied` can only be used on classes.',
      element: enviedEl,
    );
  }

  final config = Envied(
    path: annotation.read('path').literalValue as String?,
    requireEnvFile:
        annotation.read('requireEnvFile').literalValue as bool? ?? false,
    name: annotation.read('name').literalValue as String?,
    obfuscate: annotation.read('obfuscate').literalValue as bool,
  );

  final envs = await loadEnvs(config.path, (error) {
    if (config.requireEnvFile) {
      throw InvalidGenerationSourceError(
        error,
        element: enviedEl,
      );
    }
  });

  TypeChecker enviedFieldChecker = TypeChecker.fromRuntime(EnviedField);

  final lines = enviedEl.fields.map((fieldEl) {
    if (enviedFieldChecker.hasAnnotationOf(fieldEl)) {
      DartObject? dartObject = enviedFieldChecker.firstAnnotationOf(fieldEl);
      ConstantReader reader = ConstantReader(dartObject);

      String varName =
          reader.read('varName').literalValue as String? ?? fieldEl.name;

      Object? defaultValue = reader.read('defaultValue').literalValue;

      String? varValue;
      if (envs.containsKey(varName)) {
        varValue = envs[varName];
      } else if (Platform.environment.containsKey(varName)) {
        varValue = Platform.environment[varName];
      } else {
        if (defaultValue != null) {
          varValue = defaultValue.toString();
        }
      }

      final bool obfuscate =
          reader.read('obfuscate').literalValue as bool? ?? config.obfuscate;

      return (obfuscate ? generateLineEncrypted : generateLine)(
        fieldEl,
        varValue,
      );
    } else {
      return '';
    }
  });

  return '''
  class _${config.name ?? enviedEl.name} {
    ${lines.toList().join()}
  }
  ''';
}