nj/app/lib/features/stickers/bloc/sticker_bloc.dart

// 贴纸 BLoC — 通过 API 加载贴纸包和贴纸数据

import 'package:flutter/material.dart';
import 'package:nuanji_app/data/remote/api_client.dart';

// ===== 模型 =====

/// 贴纸包
class StickerPack {
  final String id;
  final String name;
  final String? description;
  final String? coverImageUrl;
  final int stickerCount;
  final bool isFree;
  final String? category;

  const StickerPack({
    required this.id,
    required this.name,
    this.description,
    this.coverImageUrl,
    this.stickerCount = 0,
    this.isFree = true,
    this.category,
  });

  /// 兼容旧 UI 的 emoji 封面（优先用 coverImageUrl，否则用默认）
  String get displayCover => coverImageUrl ?? '🎨';
}

/// 单张贴纸
class Sticker {
  final String id;
  final String packId;
  final String name;
  final String imageUrl;
  final String? category;

  const Sticker({
    required this.id,
    required this.packId,
    required this.name,
    required this.imageUrl,
    this.category,
  });
}

// ===== State =====

/// 贴纸页面状态
class StickerState {
  final List<StickerPack> packs;
  final String selectedCategory;
  final bool isLoading;
  final String? errorMessage;

  const StickerState({
    this.packs = const [],
    this.selectedCategory = '全部',
    this.isLoading = false,
    this.errorMessage,
  });

  /// 按分类过滤贴纸包
  List<StickerPack> get filteredPacks => selectedCategory == '全部'
      ? packs
      : packs.where((p) => p.category == selectedCategory).toList();

  /// 所有分类（去重 + 加"全部"）
  List<String> get categories {
    final cats = packs
        .map((p) => p.category)
        .whereType<String>()
        .toSet()
        .toList();
    return ['全部', ...cats];
  }

  StickerState copyWith({
    List<StickerPack>? packs,
    String? selectedCategory,
    bool? isLoading,
    String? errorMessage,
  }) =>
      StickerState(
        packs: packs ?? this.packs,
        selectedCategory: selectedCategory ?? this.selectedCategory,
        isLoading: isLoading ?? this.isLoading,
        errorMessage: errorMessage,
      );
}

// ===== BLoC =====

/// 贴纸 BLoC — ChangeNotifier 模式
class StickerBloc extends ChangeNotifier {
  final ApiClient _api;
  StickerState _state = const StickerState();
  StickerState get state => _state;

  StickerBloc({required ApiClient api}) : _api = api;

  /// 加载贴纸包列表
  void load() {
    _state = _state.copyWith(isLoading: true);
    notifyListeners();
    _fetchPacks();
  }

  /// 选择分类
  void selectCategory(String category) {
    _state = _state.copyWith(selectedCategory: category);
    notifyListeners();
  }

  /// 按分类加载贴纸包
  void loadByCategory(String? category) {
    _state = _state.copyWith(isLoading: true);
    notifyListeners();
    _fetchPacks(category: category);
  }

  Future<void> _fetchPacks({String? category}) async {
    try {
      final queryParams = category != null && category != '全部'
          ? {'category': category}
          : null;

      final response = await _api.get(
        '/diary/sticker-packs',
        queryParams: queryParams,
      );
      final body = response.data as Map<String, dynamic>;
      final list = body['data'] as List? ?? [];

      final packs = list.map((item) {
        final m = item as Map<String, dynamic>;
        return StickerPack(
          id: m['id'] as String,
          name: m['name'] as String,
          description: m['description'] as String?,
          coverImageUrl: m['cover_image_url'] as String?,
          stickerCount: (m['sticker_count'] as num?)?.toInt() ?? 0,
          isFree: m['is_free'] as bool? ?? true,
          category: m['category'] as String?,
        );
      }).toList();

      _state = _state.copyWith(isLoading: false, packs: packs);
    } catch (e) {
      _state = _state.copyWith(
        isLoading: false,
        errorMessage: '加载贴纸包失败',
      );
    }
    notifyListeners();
  }

  /// 获取贴纸包内的贴纸列表
  Future<List<Sticker>> fetchStickersInPack(String packId) async {
    try {
      final response = await _api.get('/diary/sticker-packs/$packId/stickers');
      final body = response.data as Map<String, dynamic>;
      final list = body['data'] as List? ?? [];

      return list.map((item) {
        final m = item as Map<String, dynamic>;
        return Sticker(
          id: m['id'] as String,
          packId: m['pack_id'] as String,
          name: m['name'] as String,
          imageUrl: m['image_url'] as String,
          category: m['category'] as String?,
        );
      }).toList();
    } catch (e) {
      return [];
    }
  }
}