import 'dart:convert';

import 'package:flutter/foundation.dart';
import 'package:patbond_flutter/data/demo_data.dart';
import 'package:patbond_flutter/models/models.dart';
import 'package:shared_preferences/shared_preferences.dart';

class AppState extends ChangeNotifier {
  static const _petKey = 'patbond_pet';
  static const _postsKey = 'patbond_posts';
  static const _locationWeatherKey = 'patbond_location_weather';

  /// 首页问候卡 / 创作页 / 主壳头像仍消费的 demo 宠物（T2-12 起档案
  /// Tab 已切独立 pets feature 真实数据；此 demo 随后续工单收敛）。
  PetProfile pet = initialPet;
  List<PostModel> posts = List<PostModel>.from(initialPosts);
  LocationWeather locationWeather = initialLocationWeather;
  bool isReady = false;

  Future<void> load() async {
    try {
      final preferences = await SharedPreferences.getInstance();
      final savedPet = preferences.getString(_petKey);
      final savedPosts = preferences.getString(_postsKey);
      final savedLocationWeather = preferences.getString(_locationWeatherKey);

      if (savedPet != null) {
        pet = PetProfile.fromJson(jsonDecode(savedPet) as Map<String, dynamic>);
      }
      if (savedPosts != null) {
        posts = (jsonDecode(savedPosts) as List)
            .map((item) => PostModel.fromJson(item as Map<String, dynamic>))
            .toList();
      }
      if (savedLocationWeather != null) {
        locationWeather = LocationWeather.fromJson(
          jsonDecode(savedLocationWeather) as Map<String, dynamic>,
        );
      }
    } catch (error, stackTrace) {
      debugPrint('读取本地数据失败，已使用默认数据：$error\n$stackTrace');
      pet = initialPet;
      posts = List<PostModel>.from(initialPosts);
      locationWeather = initialLocationWeather;
    } finally {
      isReady = true;
      notifyListeners();
    }
  }

  Future<void> updatePost(PostModel value) async {
    final index = posts.indexWhere((post) => post.id == value.id);
    if (index == -1) return;
    posts[index] = value;
    posts = List<PostModel>.from(posts);
    notifyListeners();
    await _savePosts();
  }

  Future<void> publishPost(PostModel value) async {
    posts = [value, ...posts];
    notifyListeners();
    await _savePosts();
  }

  Future<void> updateLocationWeather(LocationWeather value) async {
    locationWeather = value;
    notifyListeners();
    await _save(_locationWeatherKey, value.toJson());
  }

  Future<void> resetDemoData() async {
    pet = initialPet;
    posts = List<PostModel>.from(initialPosts);
    locationWeather = initialLocationWeather;
    notifyListeners();
    final preferences = await SharedPreferences.getInstance();
    await Future.wait([
      preferences.remove(_petKey),
      preferences.remove(_postsKey),
      preferences.remove(_locationWeatherKey),
    ]);
  }

  Future<void> _savePosts() {
    return _save(_postsKey, posts.map((post) => post.toJson()).toList());
  }

  Future<void> _save(String key, Object value) async {
    try {
      final preferences = await SharedPreferences.getInstance();
      await preferences.setString(key, jsonEncode(value));
    } catch (error, stackTrace) {
      debugPrint('保存本地数据失败：$error\n$stackTrace');
    }
  }
}