scan method

@override Future<ScannerResult> scan(ProjectContext context)

Executes the scan and returns a ScannerResult.

Implementation

@override
Future<ScannerResult> scan(ProjectContext context) async {
  context.logger.startSpinner('Scanning Packages...');
  final issues = <Issue>[];

  final dependencies = context.pubspec?['dependencies'];
  if (dependencies == null || dependencies is! Map) {
    context.logger.stopSpinner();
    return ScannerResult(issues: issues);
  }

  final declaredPackages = dependencies.keys
      .where((k) => k != 'flutter')
      .cast<String>()
      .toList();

  // Find all imports in dart code
  final libDir = Directory('${context.directory}/lib');
  List<File> dartFiles = [];
  if (libDir.existsSync()) {
    dartFiles = libDir
        .listSync(recursive: true)
        .whereType<File>()
        .where((f) => f.path.endsWith('.dart'))
        .toList();
  }

  final allDartCodeBuffer = StringBuffer();
  final Set<String> importedUris = {};

  for (final file in dartFiles) {
    final content = file.readAsStringSync();
    allDartCodeBuffer.writeln(content);

    try {
      final unit = parseString(content: content, path: file.path).unit;
      for (final directive in unit.directives) {
        if (directive is ImportDirective) {
          final uri = directive.uri.stringValue;
          if (uri != null) importedUris.add(uri);
        } else if (directive is ExportDirective) {
          final uri = directive.uri.stringValue;
          if (uri != null) importedUris.add(uri);
        }
      }
    } catch (e) {
      context.logger.verboseLog('AST parsing failed for ${file.path}: $e');
    }
  }

  final allDartCode = allDartCodeBuffer.toString();

  // Known tooling packages that might not be imported directly
  final knownToolingPackages = {
    'flutter_launcher_icons',
    'flutter_native_splash',
    'build_runner',
    'json_serializable',
    'freezed',
    'freezed_annotation',
    'rename',
    'pigeon',
    'ffi',
    'slang',
    'envied_generator',
    'json_annotation',
    'lints',
    'flutter_lints',
  };

  // Firebase packages group
  final firebasePackages = declaredPackages
      .where((p) => p.startsWith('firebase_') || p == 'cloud_firestore')
      .toList();

  for (final package in declaredPackages) {
    bool isUsed = false;

    // 1. Check if directly imported via AST
    if (importedUris.any((uri) => uri.startsWith('package:$package/'))) {
      isUsed = true;
    }

    // 2. Check if it's a known tooling package
    if (!isUsed && knownToolingPackages.contains(package)) {
      isUsed = true;
    }

    // 3. Check if configured in pubspec.yaml (e.g. flutter_launcher_icons: ...)
    if (!isUsed && context.pubspec!.containsKey(package)) {
      isUsed = true;
    }

    // 4. Special cases (e.g. firebase_core indirectly referenced)
    if (!isUsed && package == 'firebase_core') {
      if (allDartCode.contains('Firebase.initializeApp') ||
          allDartCode.contains('firebase_options.dart') ||
          firebasePackages.length > 1) {
        // If other firebase packages exist, core is implicitly needed
        isUsed = true;
      }
    }

    // 5. Special case: if another package implies this one is used
    // For instance, google_sign_in with firebase_auth
    if (!isUsed &&
        package == 'google_sign_in' &&
        firebasePackages.isNotEmpty) {
      isUsed = true;
    }

    if (!isUsed) {
      issues.add(
        Issue(
          title: 'Unused Package',
          description:
              'Package "$package" is declared in pubspec.yaml but appears unused in the project.',
          category: 'Dependencies',
          severity: IssueSeverity.medium,
          suggestion:
              'Remove it from pubspec.yaml to speed up builds and reduce size. If it is a tool, ensure it is configured.',
        ),
      );
    }
  }

  context.logger.stopSpinner();
  return ScannerResult(issues: issues);
}