import 'dart:async';

import 'package:build/build.dart';

Builder appInfoBuilder(BuilderOptions options) => _AppInfoBuilder();

class _AppInfoBuilder implements Builder {
  @override
  Map<String, List<String>> get buildExtensions => const {
        r'$package$': ['lib/app_info.g.dart'],
      };

  @override
  Future<void> build(BuildStep buildStep) async {
    final pkg = buildStep.inputId.package;
    final raw = await buildStep.readAsString(AssetId(pkg, 'pubspec.yaml'));
    final match =
        RegExp(r'^version:\s*([^\s#]+)', multiLine: true).firstMatch(raw);
    final combined = match?.group(1) ?? '0.0.0+0';
    final plus = combined.indexOf('+');
    final version = plus < 0 ? combined : combined.substring(0, plus);
    final buildNumber =
        plus < 0 ? 0 : int.tryParse(combined.substring(plus + 1)) ?? 0;

    await buildStep.writeAsString(
      AssetId(pkg, 'lib/app_info.g.dart'),
      '''
// GENERATED by build_runner from pubspec.yaml — do not edit.
import 'package:ux/ux.dart';

const kAppInfo = AppInfo(version: '$version', buildNumber: $buildNumber);
''',
    );
  }
}