generateForAnnotatedElement method

@override 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
String generateForAnnotatedElement(
  Element element,
  ConstantReader annotation,
  BuildStep buildStep,
) {
  if (element is! ClassElement) {
    throw '@BleObject can only be used on classes';
  }

  final className = element.name;
  print('Generating parser for class: $className');

  // Read default values from @BleObject annotation
  final defaultEndian = _readDefaultEndian(annotation);
  final defaultSigned = _readDefaultSigned(annotation);

  // Collect field information first
  int autoOffset = 0;
  List<String> constructorArgsUint8 = [];
  List<String> constructorArgsList = [];

  // Iterate through all fields
  for (var field in element.fields) {
    if (field.isStatic) continue;

    // Get @BleField annotation with defaults applied
    final fieldAnn = _getAnnotation(field, defaultEndian, defaultSigned);
    if (fieldAnn == null) continue;

    // 1. Determine offset
    int currentOffset = fieldAnn.offset ?? autoOffset;

    // 2. Generate read expressions for both Uint8List and List<int> versions
    String readExprUint8 = _genReadExpr(fieldAnn, currentOffset, true);
    String readExprList = _genReadExpr(fieldAnn, currentOffset, false);

    // 3. Store constructor arguments separately for each version
    constructorArgsUint8.add('${field.name}: $readExprUint8');
    constructorArgsList.add('${field.name}: $readExprList');

    // 4. Update auto offset
    autoOffset = currentOffset + fieldAnn.length;
  }

  final constructorBody = '  return $className(\n${constructorArgsUint8.join(',\n')}\n  );';
  final constructorBodyList = '  return $className(\n${constructorArgsList.join(',\n')}\n  );';

  final buffer = StringBuffer();

  // Generate Uint8List version (primary method, keeps original name)
  buffer.writeln('$className _\$${className}FromBytes(Uint8List rawData) {');
  buffer.writeln('  final view = ByteData.sublistView(rawData);');
  buffer.write(constructorBody);
  buffer.writeln('}');
  buffer.writeln('');

  // Generate List<int> version (additional method for compatibility)
  buffer.writeln('$className _\$${className}FromBytesList(List<int> rawData) {');
  buffer.writeln('  final view = ByteData.sublistView(Uint8List.fromList(rawData));');
  buffer.write(constructorBodyList);
  buffer.writeln('}');

  return buffer.toString();
}