import 'dart:async';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:firebase_core/firebase_core.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'social_feed_models.dart';
import 'social_feed_service.dart';

/// Provider for SocialFeedService singleton.
final socialFeedServiceProvider = Provider<SocialFeedService>((ref) {
  FirebaseFirestore? firestore;
  try {
    if (Firebase.apps.isNotEmpty) {
      firestore = FirebaseFirestore.instance;
    }
  } catch (_) {
    firestore = null;
  }
  final service = SocialFeedService(firestore: firestore);
  ref.onDispose(() {
    service.dispose();
  });
  return service;
});

/// State provider for the active feed stream filter tab.
final feedFilterStateProvider = StateProvider<FeedFilter>((ref) {
  return FeedFilter.allActivity;
});

/// State provider for the active riding discipline filter chip.
final feedDisciplineFilterProvider = StateProvider<RidingDiscipline>((ref) {
  return RidingDiscipline.all;
});

/// State provider for searching route titles, canyons, bikes, or handles.
final feedSearchQueryProvider = StateProvider<String>((ref) {
  return '';
});

/// State provider for minimum ride distance threshold.
final feedMinDistanceFilterProvider = StateProvider<double?>((ref) {
  return null;
});

/// State provider for GPS verified only filter toggle.
final feedVerifiedGpsOnlyProvider = StateProvider<bool>((ref) {
  return false;
});

/// StateNotifier providing instant synchronous initial feed items and reacting to changes.
class SocialFeedNotifier extends StateNotifier<List<SocialFeedItem>> {
  final SocialFeedService _service;
  final FeedFilter _filter;
  final RidingDiscipline _discipline;
  final String? _searchQuery;
  final double? _minDistanceMiles;
  final bool? _verifiedGpsOnly;
  StreamSubscription<List<SocialFeedItem>>? _sub;

  SocialFeedNotifier(
    this._service,
    this._filter, {
    RidingDiscipline discipline = RidingDiscipline.all,
    String? searchQuery,
    double? minDistanceMiles,
    bool? verifiedGpsOnly,
  })  : _discipline = discipline,
        _searchQuery = searchQuery,
        _minDistanceMiles = minDistanceMiles,
        _verifiedGpsOnly = verifiedGpsOnly,
        super(_service.getFilteredItems(
          filter: _filter,
          discipline: discipline,
          searchQuery: searchQuery,
          minDistanceMiles: minDistanceMiles,
          verifiedGpsOnly: verifiedGpsOnly,
        )) {
    _sub = _service
        .getFeedStream(
          filter: _filter,
          discipline: _discipline,
          searchQuery: _searchQuery,
          minDistanceMiles: _minDistanceMiles,
          verifiedGpsOnly: _verifiedGpsOnly,
        )
        .listen((items) {
      state = items;
    });
  }

  @override
  void dispose() {
    _sub?.cancel();
    super.dispose();
  }
}

/// Primary feed provider with zero-latency synchronous initial data.
final socialFeedNotifierProvider =
    StateNotifierProvider.autoDispose<SocialFeedNotifier, List<SocialFeedItem>>(
        (ref) {
  final service = ref.watch(socialFeedServiceProvider);
  final filter = ref.watch(feedFilterStateProvider);
  final discipline = ref.watch(feedDisciplineFilterProvider);
  final searchQuery = ref.watch(feedSearchQueryProvider);
  final minDistance = ref.watch(feedMinDistanceFilterProvider);
  final verifiedGpsOnly = ref.watch(feedVerifiedGpsOnlyProvider);

  return SocialFeedNotifier(
    service,
    filter,
    discipline: discipline,
    searchQuery: searchQuery,
    minDistanceMiles: minDistance,
    verifiedGpsOnly: verifiedGpsOnly,
  );
});

/// Stream provider for the filtered community social feed (preserved for backwards compatibility).
final socialFeedStreamProvider =
    StreamProvider.autoDispose<List<SocialFeedItem>>((ref) {
  final service = ref.watch(socialFeedServiceProvider);
  final filter = ref.watch(feedFilterStateProvider);
  final discipline = ref.watch(feedDisciplineFilterProvider);
  final searchQuery = ref.watch(feedSearchQueryProvider);

  return service.getFeedStream(
    filter: filter,
    discipline: discipline,
    searchQuery: searchQuery,
  );
});