import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:im_app/app/di/user_provider.dart';
import 'package:im_app/domain/entities/user.dart';
import 'package:im_app/domain/repositories/user_repository.dart';

/// 单个用户状态管理 (family — 每个 uid 独立 notifier)
///
/// ## 用法
/// ```dart
/// // 监听 — 自动重建
/// final userAsync = ref.watch(userNotifierProvider(123));
///
/// // 即时读取，无需 await
/// final user = ref.read(userNotifierProvider(123).notifier).current;
///
/// // 插入或替换
/// ref.read(userNotifierProvider(123).notifier).insertOrReplaceUser(user);
///
/// // 单个更新
/// ref.read(userNotifierProvider(123).notifier).updateUser(
///   user.copyWith(nickname: 'New Name'),
/// );
///
/// // 批量更新
/// ref.read(userNotifierProvider(123).notifier).updateUsers(updatedList);
/// ```
class UserNotifier extends FamilyAsyncNotifier<User?, int> {
  User? _cached;

  UserRepository get _repo => ref.watch(userRepositoryProvider);

  @override
  Future<User?> build(int arg) async {
    ref.onDispose(() => _cached = null);

    _repo.watchUser(arg).listen((user) {
      _cached = user;
      state = AsyncData(user);
    });

    return _repo.getUser(arg);
  }

  // ── 即时访问，无需 await ──────────────────────────────────────────────────

  User? get current => _cached;

  // ── 写入 ─────────────────────────────────────────────────────────────────

  /// 插入或替换单个用户
  Future<void> insertOrReplaceUser(User user) async {
    await _repo.insertOrReplaceUser(user);
  }

  /// 更新单个用户所有字段，按 uid 匹配
  Future<void> updateUser(User user) async {
    await _repo.updateUser(user);
  }

  /// 批量更新用户，每条按 uid 匹配更新所有字段
  Future<void> updateUsers(List<User> users) async {
    await _repo.updateUsersBatch(users);
  }

  // ── 删除 ─────────────────────────────────────────────────────────────────

  Future<void> deleteUser() async {
    await _repo.deleteUser(arg);
    _cached = null;
    state = const AsyncData(null);
  }
}

final userNotifierProvider =
    AsyncNotifierProvider.family<UserNotifier, User?, int>(UserNotifier.new);