import 'package:flutter/services.dart' show AssetBundle, rootBundle;
import 'package:flutter_riverpod/flutter_riverpod.dart';

import '../../core/region/region_repository.dart';
import 'comune.dart';

/// Loads the bundled municipality list.
class ComuniRepository {
  const ComuniRepository({this.bundle});

  /// Overridden in tests; null means the real asset bundle.
  final AssetBundle? bundle;

  AssetBundle get _assets => bundle ?? rootBundle;

  static String assetPathFor(String regionId) =>
      'assets/regions/${regionId}_comuni.json';

  Future<ComuneIndex> load(String regionId) async {
    final source = await _assets.loadString(assetPathFor(regionId));
    return ComuneIndex.parse(source);
  }
}

final comuniRepositoryProvider = Provider<ComuniRepository>(
  (ref) => const ComuniRepository(),
);

/// The searchable municipality index for the active region.
///
/// Loaded once and kept: 1180 entries with a precomputed fold key is a
/// negligible amount of memory next to a single radar frame, and rebuilding it
/// per search would make typing feel slow for no reason.
final comuneIndexProvider = FutureProvider<ComuneIndex>((ref) async {
  final regionId = ref.watch(regionIdProvider);
  return ref.watch(comuniRepositoryProvider).load(regionId);
});