import '../../core/exceptions.dart';
import '../api/events_api.dart';
import '../local/database.dart';
import '../models/calendar_event.dart';

/// Calendar events repository with read-through caching for Tier 2 offline
/// support. Range-scoped: each `getEvents(from, to)` mirrors that window into
/// the cache (events outside the window are left alone) so successive
/// disjoint range fetches don't clobber each other.
class EventsRepository {
  final EventsApi _api;
  final FabledDatabase _db;

  const EventsRepository(this._api, this._db);

  Future<List<CalendarEvent>> getEvents(DateTime from, DateTime to) async {
    try {
      final events = await _api.getEvents(from, to);
      await _db.replaceEventsInRange(from, to, events);
      return events;
    } on NetworkException {
      final cached = await _db.getEventsInRange(from, to);
      if (cached.isEmpty) rethrow;
      return cached;
    }
  }

  Future<CalendarEvent> createEvent(Map<String, dynamic> payload) async {
    final event = await _api.createEvent(payload);
    await _db.upsertEvent(event);
    return event;
  }

  Future<CalendarEvent> updateEvent(
      int id, Map<String, dynamic> fields) async {
    final updated = await _api.updateEvent(id, fields);
    await _db.upsertEvent(updated);
    return updated;
  }

  Future<void> deleteEvent(int id) async {
    await _api.deleteEvent(id);
    await _db.deleteEvent(id);
  }
}