import 'package:build/build.dart';
import 'package:xml/xml.dart';
import 'package:glob/glob.dart';

Builder stringXmlWatcherBuilder(BuilderOptions options) {
  return StringXmlWatcherBuilder();
}

class StringXmlWatcherBuilder implements Builder {
  static const _baseType = 'zh_CN';
  static final _targetXmlGlob = Glob('assets/string/base/*.xml');

  @override
  Future<void> build(BuildStep buildStep) async {
    final xmlFiles = await buildStep.findAssets(_targetXmlGlob).toList();
    final (buffer, multiBuffer) = await _processXmlFiles(buildStep, xmlFiles);

    final outputId = AssetId(
      buildStep.inputId.package,
      'lib/resource/string.gen.dart',
    );
    await buildStep.writeAsString(outputId, buffer.toString() + multiBuffer.toString());
  }

  Future<(StringBuffer, StringBuffer)> _processXmlFiles(
      BuildStep buildStep,
      List<AssetId> xmlFiles,
      ) async {
    final buffer = StringBuffer();
    final multiBuffer = StringBuffer();
    buffer.writeln('import \'package:get/get.dart\';');
    buffer.writeln();
    buffer.writeln('class StringName {');
    buffer.writeln('  StringName._();');
    multiBuffer.writeln('class StringMultiSource {');
    multiBuffer.writeln('  StringMultiSource._();');
    multiBuffer.writeln('  static const Map<String, Map<String, String>> values = {');

    multiBuffer.writeln('    \'${_baseType}\': {');

    for (final file in xmlFiles) {
      final content = await buildStep.readAsString(file);
      final document = XmlDocument.parse(content);

      for (final element in document.findAllElements('string')) {
        final name = element.getAttribute('name');
        final value = _sanitizeValue(element.text);

        if (name != null) {
          final camelCaseName = _toCamelCase(name);
          buffer.writeln(
              '  static final String $camelCaseName = \'$name\'.tr;// $value');
          multiBuffer.writeln('      \'$name\': \'$value\',');
        }
      }
    }

    multiBuffer.writeln('    },');
    buffer.writeln('}');
    multiBuffer.writeln('  };');
    multiBuffer.writeln('}');

    return (buffer, multiBuffer);
  }

  String _sanitizeValue(String value) => value.replaceAll('\r\n', '').trim();

  String _toCamelCase(String snakeCase) {
    return snakeCase.split('_').map((word) {
      if (word == snakeCase.split('_').first) return word;
      return word[0].toUpperCase() + word.substring(1);
    }).join('');
  }

  @override
  Map<String, List<String>> get buildExtensions => {
    r'$package$': ['lib/resource/string.gen.dart'],
  };
}