import 'package:flutter/material.dart';
import 'package:patbond_flutter/core/theme/app_theme.dart';
import 'package:patbond_flutter/core/widgets/empty_state_illustration.dart';
import 'package:patbond_flutter/core/widgets/feed_skeleton.dart';
import 'package:patbond_flutter/core/widgets/inline_error_banner.dart';
import 'package:patbond_flutter/core/widgets/post_card.dart';
import 'package:patbond_flutter/data/demo_data.dart';
import 'package:patbond_flutter/features/community/community_controller.dart';
import 'package:patbond_flutter/features/community/community_display.dart';
import 'package:patbond_flutter/features/community/community_models.dart';
import 'package:patbond_flutter/features/community/feed_analytics.dart';
import 'package:patbond_flutter/features/community/feed_exposure.dart';
import 'package:patbond_flutter/models/models.dart';
import 'package:patbond_flutter/state/app_state.dart';
import 'package:patbond_flutter/widgets/common.dart';

enum HomeSegment { feed, services }

/// 首页 Tab：Feed 段自 T3-14 起消费 [CommunityController] 真实数据
/// （四态 + 游标翻页 + 聚合曝光埋点）；天气条/问候卡/搜索/服务段与
/// `_StoryRow` 家具保留 demo 形态（03 号评估 §1.1 判定）。
class HomePage extends StatefulWidget {
  const HomePage({
    required this.appState,
    required this.communityController,
    required this.onOpenServices,
    required this.onOpenCreate,
    super.key,
    this.onOpenPost,
    this.feedAnalytics,
    this.isActive = true,
  });

  final AppState appState;

  /// Feed 数据源（Tab 级单例，app.dart 装配注入）。
  final CommunityController communityController;

  final ValueChanged<bool> onOpenServices;
  final VoidCallback onOpenCreate;

  /// 帖子详情导航（T3-15 接通；主壳 push PostDetailPage）。
  final ValueChanged<String>? onOpenPost;

  /// feed 域埋点（feed_viewed 聚合曝光 + feed_load_failed）。
  final FeedAnalytics? feedAnalytics;

  /// 首页 Tab 是否为当前可见 Tab（IndexedStack 各 Tab 常驻构建，
  /// 由主壳传入以驱动浏览段开/结算）。
  final bool isActive;

  @override
  State<HomePage> createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> with WidgetsBindingObserver {
  HomeSegment segment = HomeSegment.feed;
  String query = '';
  String sort = '综合';

  /// 当前 Feed 浏览段（不在 Feed 面上时为 null）。
  FeedViewSegment? _viewSegment;

  /// 曝光扫描用：postId → 卡片 GlobalKey。
  final Map<String, GlobalKey> _cardKeys = {};
  final GlobalKey _listKey = GlobalKey();

  AppLifecycleState _lastLifecycle = AppLifecycleState.resumed;

  CommunityController get _feed => widget.communityController;

  bool get _feedSurfaceVisible =>
      widget.isActive && segment == HomeSegment.feed;

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addObserver(this);
    // 主壳挂载即预取（pets 先例）；重登后控制器已 reset 回 initial。
    // 首屏自动预取不计入浏览段 refreshCount（非用户动作）。
    if (_feed.phase == FeedPhase.initial) {
      _refreshFeed(userInitiated: false);
    }
    if (_feedSurfaceVisible) _startSegment();
  }

  @override
  void didUpdateWidget(HomePage oldWidget) {
    super.didUpdateWidget(oldWidget);
    if (oldWidget.isActive != widget.isActive) {
      widget.isActive ? _maybeStartSegment() : _settleSegment();
    }
  }

  @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
    // 退后台即结算浏览段（06 §1.2：feed_viewed 触发点之一）；只在离开
    // resumed 的第一次变更结算（inactive/hidden/paused 级联不重复）。
    // 回前台若仍在 Feed 面上则开新段。
    if (state == AppLifecycleState.resumed) {
      _lastLifecycle = state;
      _maybeStartSegment();
      return;
    }
    if (_lastLifecycle == AppLifecycleState.resumed) {
      _settleSegment();
    }
    _lastLifecycle = state;
  }

  @override
  void dispose() {
    _settleSegment();
    WidgetsBinding.instance.removeObserver(this);
    super.dispose();
  }

  // ---- 浏览段开/结算 ----

  void _startSegment() {
    _viewSegment ??= FeedViewSegment();
    _scheduleVisibilityScan();
  }

  void _maybeStartSegment() {
    if (_feedSurfaceVisible && _lastLifecycle == AppLifecycleState.resumed) {
      _startSegment();
    }
  }

  void _settleSegment() {
    final summary = _viewSegment?.settle();
    _viewSegment = null;
    if (summary != null && widget.feedAnalytics != null) {
      summary.report(widget.feedAnalytics!);
    }
  }

  void _onSegmentChanged(HomeSegment value) {
    if (value == segment) return;
    setState(() => segment = value);
    value == HomeSegment.feed ? _maybeStartSegment() : _settleSegment();
  }

  // ---- 曝光可见性扫描 ----

  bool _scanScheduled = false;

  /// 帧末扫描（滚动通知发生在本帧布局前，同步读 RenderBox 是旧位置；
  /// 统一调度到 post-frame，一帧至多一次）。
  void _scheduleVisibilityScan() {
    if (_scanScheduled) return;
    _scanScheduled = true;
    WidgetsBinding.instance.addPostFrameCallback((_) {
      _scanScheduled = false;
      _scanVisibility();
    });
  }

  /// 以列表视口与各卡片 RenderBox 的纵向交叠比例回报可见性
  /// （≥50% 且驻留 ≥500ms 才计曝光，判定在 [FeedViewSegment] 内）。
  void _scanVisibility() {
    final viewSegment = _viewSegment;
    if (viewSegment == null || !mounted) return;
    final listBox = _listKey.currentContext?.findRenderObject() as RenderBox?;
    if (listBox == null || !listBox.attached) return;
    final viewportTop = listBox.localToGlobal(Offset.zero).dy;
    final viewportBottom = viewportTop + listBox.size.height;
    for (final entry in _cardKeys.entries) {
      final box = entry.value.currentContext?.findRenderObject() as RenderBox?;
      var fraction = 0.0;
      if (box != null && box.attached && box.hasSize && box.size.height > 0) {
        final top = box.localToGlobal(Offset.zero).dy;
        final bottom = top + box.size.height;
        final visible =
            bottom.clamp(viewportTop, viewportBottom) -
            top.clamp(viewportTop, viewportBottom);
        fraction = visible / box.size.height;
      }
      viewSegment.updateVisibility(entry.key, fraction);
    }
  }

  bool _onScrollNotification(ScrollNotification notification) {
    if (segment != HomeSegment.feed) return false;
    if (notification is ScrollUpdateNotification ||
        notification is ScrollEndNotification) {
      _scheduleVisibilityScan();
      // 滚动近底触发翻页（余量 400 提前预取）；失败态不自动重试，
      // 只走尾部重试条显式点按（避免滚动风暴反复打失败端点）。
      if (notification.metrics.extentAfter < 400 &&
          _feed.loadMorePhase == LoadMorePhase.idle) {
        _loadMoreFeed();
      }
    }
    return false;
  }

  // ---- 数据加载与失败埋点 ----

  Future<void> _refreshFeed({required bool userInitiated}) async {
    if (userInitiated) _viewSegment?.recordRefresh();
    await _feed.refresh();
    final error = _feed.refreshError ?? _feed.lastError;
    if (error != null) {
      widget.feedAnalytics?.feedLoadFailedFrom(
        error,
        feedTab: FeedTab.home,
        loadType: FeedLoadType.refresh,
      );
    }
    // 刷新失败但旧列表被保留：SnackBar 轻提示（首屏失败走 error 态横幅）。
    if (_feed.refreshError != null && mounted) {
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text(feedLoadErrorMessage(_feed.refreshError))),
      );
    }
  }

  Future<void> _loadMoreFeed() async {
    if (_feed.phase != FeedPhase.ready ||
        !_feed.hasMore ||
        _feed.loadMorePhase == LoadMorePhase.loading) {
      return;
    }
    _viewSegment?.recordLoadMore();
    await _feed.loadMore();
    final error = _feed.loadMoreError;
    if (error != null) {
      widget.feedAnalytics?.feedLoadFailedFrom(
        error,
        feedTab: FeedTab.home,
        loadType: FeedLoadType.loadMore,
      );
    }
  }

  /// 搜索词过滤（demo 交互保留：只过滤已加载的多页缓存，不发检索请求；
  /// 契约 v1.3.0 无搜索端点）。
  List<FeedCard> get _visibleCards {
    final keyword = query.trim().toLowerCase();
    if (keyword.isEmpty) return _feed.feed;
    return _feed.feed.where((card) {
      return card.contentPreview.toLowerCase().contains(keyword) ||
          (card.title?.toLowerCase().contains(keyword) ?? false) ||
          authorDisplayName(card.author).toLowerCase().contains(keyword);
    }).toList();
  }

  List<ServiceProviderModel> get filteredProviders {
    final keyword = query.trim().toLowerCase();
    final result = serviceProviders.where((provider) {
      if (keyword.isEmpty) return true;
      return provider.name.toLowerCase().contains(keyword) ||
          provider.description.toLowerCase().contains(keyword) ||
          provider.tags.any((tag) => tag.toLowerCase().contains(keyword));
    }).toList();
    if (sort == '距离') {
      result.sort(
        (a, b) => double.parse(
          a.distance.replaceAll('km', ''),
        ).compareTo(double.parse(b.distance.replaceAll('km', ''))),
      );
    } else if (sort == '评分') {
      result.sort((a, b) => b.rating.compareTo(a.rating));
    }
    return result;
  }

  String get greeting {
    final hour = DateTime.now().hour;
    if (hour < 6) return '夜深了';
    if (hour < 11) return '早上好';
    if (hour < 14) return '中午好';
    if (hour < 18) return '下午好';
    return '晚上好';
  }

  Future<void> selectArea() async {
    final selected = await showModalBottomSheet<LocationWeather>(
      context: context,
      useSafeArea: true,
      showDragHandle: true,
      builder: (context) {
        return _AreaPickerSheet(current: widget.appState.locationWeather);
      },
    );
    if (selected != null) {
      await widget.appState.updateLocationWeather(selected);
    }
  }

  Future<void> showWeatherDetails() {
    final weather = widget.appState.locationWeather;
    return showModalBottomSheet<void>(
      context: context,
      useSafeArea: true,
      showDragHandle: true,
      builder: (context) => _WeatherDetailsSheet(weather: weather),
    );
  }

  @override
  Widget build(BuildContext context) {
    return ListenableBuilder(
      listenable: _feed,
      builder: (context, _) {
        // 点赞/收藏对账失败的一次性 SnackBar（§3.5 回滚提示；与详情页
        // 共用 controller 的 toggleError 消费口，先消费者清空）。
        if (_feed.toggleError != null) {
          _feed.clearToggleError();
          WidgetsBinding.instance.addPostFrameCallback((_) {
            if (!mounted) return;
            ScaffoldMessenger.of(
              context,
            ).showSnackBar(const SnackBar(content: Text('操作失败，请重试')));
          });
        }
        // ready 后（含翻页追加）补一次可见性扫描：无滚动也能记首屏曝光。
        if (_viewSegment != null && _feed.phase == FeedPhase.ready) {
          _scheduleVisibilityScan();
        }
        return NotificationListener<ScrollNotification>(
          onNotification: _onScrollNotification,
          child: RefreshIndicator(
            onRefresh: () => segment == HomeSegment.feed
                ? _refreshFeed(userInitiated: true)
                : Future<void>.delayed(const Duration(milliseconds: 500)),
            child: ListView(
              key: _listKey,
              padding: const EdgeInsets.fromLTRB(16, 12, 16, 28),
              children: [
                _WeatherStatusBar(
                  weather: widget.appState.locationWeather,
                  onAreaTap: selectArea,
                  onWeatherTap: showWeatherDetails,
                ),
                const SizedBox(height: 12),
                _PetGreetingCard(
                  greeting: greeting,
                  petName: widget.appState.pet.name,
                  petAvatar: widget.appState.pet.avatarUrl,
                  advice: widget.appState.locationWeather.petAdvice,
                ),
                const SizedBox(height: 14),
                TextField(
                  onChanged: (value) => setState(() => query = value),
                  decoration: const InputDecoration(
                    hintText: '搜索动态、医院、美容或遛狗服务…',
                    prefixIcon: Icon(Icons.search),
                  ),
                ),
                const SizedBox(height: 14),
                SegmentedButton<HomeSegment>(
                  segments: const [
                    ButtonSegment(
                      value: HomeSegment.feed,
                      icon: Icon(Icons.forum_outlined),
                      label: Text('社区动态'),
                    ),
                    ButtonSegment(
                      value: HomeSegment.services,
                      icon: Icon(Icons.storefront_outlined),
                      label: Text('本地服务'),
                    ),
                  ],
                  selected: {segment},
                  showSelectedIcon: false,
                  onSelectionChanged: (value) => _onSegmentChanged(value.first),
                ),
                const SizedBox(height: 18),
                if (segment == HomeSegment.feed) ...[
                  _StoryRow(onCreate: widget.onOpenCreate),
                  const SizedBox(height: 18),
                  _PromoCard(onTap: () => widget.onOpenServices(true)),
                  const SizedBox(height: 18),
                  ..._feedSection(),
                ] else ...[
                  _CategoryGrid(onTap: (_) => widget.onOpenServices(false)),
                  const SizedBox(height: 18),
                  Row(
                    children: [
                      Text(
                        '附近推荐',
                        style: Theme.of(context).textTheme.titleLarge,
                      ),
                      const Spacer(),
                      for (final item in ['综合', '距离', '评分'])
                        Padding(
                          padding: const EdgeInsets.only(left: 6),
                          child: ChoiceChip(
                            label: Text(item),
                            selected: sort == item,
                            onSelected: (_) => setState(() => sort = item),
                          ),
                        ),
                    ],
                  ),
                  const SizedBox(height: 12),
                  if (filteredProviders.isEmpty)
                    const EmptyState(message: '没有找到相关服务')
                  else
                    ...filteredProviders.map(
                      (provider) => Padding(
                        padding: const EdgeInsets.only(bottom: 12),
                        child: _ProviderCompactCard(
                          provider: provider,
                          onTap: () => widget.onOpenServices(
                            provider.kind == ProviderKind.personal,
                          ),
                        ),
                      ),
                    ),
                ],
              ],
            ),
          ),
        );
      },
    );
  }

  // ---- Feed 段四态渲染 ----

  List<Widget> _feedSection() {
    switch (_feed.phase) {
      case FeedPhase.initial:
      case FeedPhase.loading:
        return const [
          FeedSkeleton(),
          SizedBox(height: 16),
          FeedSkeleton(),
          SizedBox(height: 16),
          FeedSkeleton(),
        ];
      case FeedPhase.error:
        return [
          Padding(
            padding: const EdgeInsets.symmetric(vertical: 24),
            child: Column(
              children: [
                InlineErrorBanner(
                  message: feedLoadErrorMessage(_feed.lastError),
                ),
                const SizedBox(height: 16),
                FilledButton(
                  onPressed: () => _refreshFeed(userInitiated: true),
                  child: const Text('重试'),
                ),
              ],
            ),
          ),
        ];
      case FeedPhase.ready:
        if (_feed.feed.isEmpty) {
          return [
            EmptyStateIllustration(
              icon: Icons.forum_outlined,
              title: '还没有动态',
              description: '关注的毛孩子们还没发帖，去逛逛话题吧',
              ctaLabel: '发布第一条',
              onCtaPressed: widget.onOpenCreate,
            ),
          ];
        }
        final cards = _visibleCards;
        _pruneCardKeys(cards);
        if (cards.isEmpty) {
          return const [EmptyState(message: '没有找到相关动态')];
        }
        return [
          for (final card in cards)
            Padding(
              padding: const EdgeInsets.only(bottom: 16),
              child: KeyedSubtree(
                key: _cardKeys.putIfAbsent(card.id, GlobalKey.new),
                // 点赞/收藏经共享 ToggleSync（source=feed 缺省）；整卡与
                // 评论钮进详情（T3-15 导航接通，T3-14 的占位提示移除）。
                child: PostCard(
                  card: card,
                  onTap: () => widget.onOpenPost?.call(card.id),
                  onCommentTap: () => widget.onOpenPost?.call(card.id),
                  onLikeTap: () => _feed.toggleLike(card.id),
                  onBookmarkTap: () => _feed.toggleBookmark(card.id),
                ),
              ),
            ),
          // 搜索过滤中不渲染尾部（过滤只作用于已加载页，翻页语义混淆）。
          if (query.trim().isEmpty) _feedTail(),
        ];
    }
  }

  /// 卡片 key 表随当前列表收敛（刷新整体替换后旧帖的驻留计时作废）。
  void _pruneCardKeys(List<FeedCard> cards) {
    final alive = {for (final card in cards) card.id};
    _cardKeys.removeWhere((id, _) {
      if (alive.contains(id)) return false;
      _viewSegment?.updateVisibility(id, 0);
      return true;
    });
  }

  /// 尾部三态：加载中转圈 / 失败重试 / 到底「没有更多了」。
  Widget _feedTail() {
    switch (_feed.loadMorePhase) {
      case LoadMorePhase.loading:
        return const Padding(
          padding: EdgeInsets.symmetric(vertical: 16),
          child: Center(
            child: SizedBox(
              width: 24,
              height: 24,
              child: CircularProgressIndicator(
                strokeWidth: 2.5,
                color: AppColors.primary,
              ),
            ),
          ),
        );
      case LoadMorePhase.error:
        return Padding(
          padding: const EdgeInsets.symmetric(vertical: 8),
          child: Column(
            children: [
              Text(
                feedLoadErrorMessage(_feed.loadMoreError),
                style: const TextStyle(color: AppColors.inkSoft, fontSize: 12),
              ),
              TextButton(
                onPressed: _loadMoreFeed,
                child: const Text('加载失败，点此重试'),
              ),
            ],
          ),
        );
      case LoadMorePhase.idle:
        if (_feed.hasMore) return const SizedBox(height: 24);
        return const Padding(
          padding: EdgeInsets.symmetric(vertical: 16),
          child: Center(
            child: Text(
              '没有更多了',
              style: TextStyle(color: AppColors.inkSoft, fontSize: 12),
            ),
          ),
        );
    }
  }
}

class _WeatherStatusBar extends StatelessWidget {
  const _WeatherStatusBar({
    required this.weather,
    required this.onAreaTap,
    required this.onWeatherTap,
  });

  final LocationWeather weather;
  final VoidCallback onAreaTap;
  final VoidCallback onWeatherTap;

  @override
  Widget build(BuildContext context) {
    return Row(
      children: [
        Expanded(
          child: InkWell(
            key: const ValueKey('area-selector'),
            onTap: onAreaTap,
            borderRadius: BorderRadius.circular(14),
            child: Padding(
              padding: const EdgeInsets.symmetric(vertical: 7, horizontal: 3),
              child: Row(
                children: [
                  const Icon(
                    Icons.location_on_outlined,
                    size: 21,
                    color: AppColors.ink,
                  ),
                  const SizedBox(width: 5),
                  Flexible(
                    child: Text(
                      weather.displayArea,
                      maxLines: 1,
                      overflow: TextOverflow.ellipsis,
                      style: const TextStyle(
                        fontSize: 13,
                        fontWeight: FontWeight.w800,
                      ),
                    ),
                  ),
                  const SizedBox(width: 3),
                  const Icon(
                    Icons.keyboard_arrow_down,
                    size: 18,
                    color: AppColors.muted,
                  ),
                ],
              ),
            ),
          ),
        ),
        InkWell(
          key: const ValueKey('weather-details'),
          onTap: onWeatherTap,
          borderRadius: BorderRadius.circular(99),
          child: Container(
            padding: const EdgeInsets.symmetric(horizontal: 11, vertical: 7),
            decoration: BoxDecoration(
              color: _weatherColor(weather.condition).withAlpha(22),
              borderRadius: BorderRadius.circular(99),
            ),
            child: Row(
              children: [
                Icon(
                  _weatherIcon(weather.condition),
                  size: 19,
                  color: _weatherColor(weather.condition),
                ),
                const SizedBox(width: 5),
                Text(
                  '${weather.temperature}°C ${weather.conditionText}',
                  style: const TextStyle(
                    fontSize: 13,
                    fontWeight: FontWeight.w800,
                  ),
                ),
              ],
            ),
          ),
        ),
      ],
    );
  }
}

class _PetGreetingCard extends StatelessWidget {
  const _PetGreetingCard({
    required this.greeting,
    required this.petName,
    required this.petAvatar,
    required this.advice,
  });

  final String greeting;
  final String petName;
  final String petAvatar;
  final String advice;

  @override
  Widget build(BuildContext context) {
    return Container(
      height: 138,
      clipBehavior: Clip.antiAlias,
      decoration: BoxDecoration(
        borderRadius: BorderRadius.circular(26),
        gradient: const LinearGradient(
          begin: Alignment.topLeft,
          end: Alignment.bottomRight,
          colors: [AppColors.surfaceTint, AppColors.canvas],
        ),
      ),
      child: Stack(
        children: [
          Positioned(
            left: 160,
            top: 15,
            child: Icon(
              Icons.pets,
              size: 28,
              color: AppColors.primary.withAlpha(34),
            ),
          ),
          Positioned(
            right: -5,
            bottom: -10,
            child: RemoteImage(
              url: petAvatar,
              width: 145,
              height: 145,
              borderRadius: BorderRadius.circular(72),
            ),
          ),
          Padding(
            padding: const EdgeInsets.fromLTRB(18, 19, 130, 17),
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(
                  '$greeting，$petName 👋',
                  maxLines: 1,
                  overflow: TextOverflow.ellipsis,
                  style: const TextStyle(
                    color: AppColors.ink,
                    fontSize: 20,
                    fontWeight: FontWeight.w900,
                  ),
                ),
                const SizedBox(height: 7),
                Text(
                  advice,
                  maxLines: 3,
                  overflow: TextOverflow.ellipsis,
                  style: const TextStyle(
                    color: AppColors.primaryDark,
                    fontSize: 12,
                    height: 1.45,
                    fontWeight: FontWeight.w600,
                  ),
                ),
              ],
            ),
          ),
        ],
      ),
    );
  }
}

class _AreaPickerSheet extends StatelessWidget {
  const _AreaPickerSheet({required this.current});

  final LocationWeather current;

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.fromLTRB(20, 0, 20, 24),
      child: Column(
        mainAxisSize: MainAxisSize.min,
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text('选择地区', style: Theme.of(context).textTheme.titleLarge),
          const SizedBox(height: 4),
          Text(
            '当前为演示天气，选择后会保存在本机。',
            style: Theme.of(context).textTheme.bodySmall,
          ),
          const SizedBox(height: 14),
          Flexible(
            child: ListView.separated(
              shrinkWrap: true,
              itemCount: locationWeatherOptions.length,
              separatorBuilder: (_, _) => const Divider(height: 1),
              itemBuilder: (context, index) {
                final option = locationWeatherOptions[index];
                final selected =
                    option.city == current.city &&
                    option.district == current.district;
                return ListTile(
                  contentPadding: EdgeInsets.zero,
                  leading: CircleAvatar(
                    backgroundColor: _weatherColor(
                      option.condition,
                    ).withAlpha(22),
                    child: Icon(
                      _weatherIcon(option.condition),
                      color: _weatherColor(option.condition),
                    ),
                  ),
                  title: Text(
                    option.displayArea,
                    style: const TextStyle(fontWeight: FontWeight.w800),
                  ),
                  subtitle: Text(
                    '${option.conditionText} · ${option.lowTemperature}° / ${option.highTemperature}°',
                  ),
                  trailing: selected
                      ? const Icon(Icons.check_circle, color: AppColors.primary)
                      : Text('${option.temperature}°C'),
                  onTap: () => Navigator.pop(context, option),
                );
              },
            ),
          ),
        ],
      ),
    );
  }
}

class _WeatherDetailsSheet extends StatelessWidget {
  const _WeatherDetailsSheet({required this.weather});

  final LocationWeather weather;

  @override
  Widget build(BuildContext context) {
    return Padding(
      padding: const EdgeInsets.fromLTRB(20, 0, 20, 28),
      child: Column(
        mainAxisSize: MainAxisSize.min,
        crossAxisAlignment: CrossAxisAlignment.start,
        children: [
          Text(
            weather.displayArea,
            style: Theme.of(context).textTheme.titleLarge,
          ),
          const SizedBox(height: 18),
          Row(
            children: [
              Icon(
                _weatherIcon(weather.condition),
                color: _weatherColor(weather.condition),
                size: 56,
              ),
              const SizedBox(width: 16),
              Text(
                '${weather.temperature}°',
                style: const TextStyle(
                  fontSize: 44,
                  fontWeight: FontWeight.w300,
                ),
              ),
              const SizedBox(width: 8),
              Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text(
                    weather.conditionText,
                    style: const TextStyle(fontWeight: FontWeight.w800),
                  ),
                  Text(
                    '${weather.lowTemperature}° / ${weather.highTemperature}°',
                    style: Theme.of(context).textTheme.bodySmall,
                  ),
                ],
              ),
              const Spacer(),
              Column(
                crossAxisAlignment: CrossAxisAlignment.end,
                children: [
                  const Text('湿度'),
                  Text(
                    '${weather.humidity}%',
                    style: const TextStyle(fontWeight: FontWeight.w800),
                  ),
                ],
              ),
            ],
          ),
          const SizedBox(height: 20),
          Container(
            width: double.infinity,
            padding: const EdgeInsets.all(16),
            decoration: BoxDecoration(
              color: AppColors.surfaceTint,
              borderRadius: BorderRadius.circular(18),
            ),
            child: Row(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                const Icon(Icons.pets, color: AppColors.primary),
                const SizedBox(width: 10),
                Expanded(child: Text(weather.petAdvice)),
              ],
            ),
          ),
        ],
      ),
    );
  }
}

IconData _weatherIcon(WeatherCondition condition) {
  return switch (condition) {
    WeatherCondition.sunny => Icons.wb_sunny_rounded,
    WeatherCondition.cloudy => Icons.cloud_queue_rounded,
    WeatherCondition.rainy => Icons.water_drop_rounded,
    WeatherCondition.overcast => Icons.cloud_rounded,
    WeatherCondition.snow => Icons.ac_unit_rounded,
  };
}

Color _weatherColor(WeatherCondition condition) {
  return switch (condition) {
    WeatherCondition.sunny => AppColors.warning,
    WeatherCondition.cloudy => AppColors.muted,
    WeatherCondition.rainy => const Color(0xFF0284C7),
    WeatherCondition.overcast => AppColors.ink,
    WeatherCondition.snow => const Color(0xFF0891B2),
  };
}

class _StoryRow extends StatelessWidget {
  const _StoryRow({required this.onCreate});

  final VoidCallback onCreate;

  @override
  Widget build(BuildContext context) {
    final stories = [
      ('发布', Icons.add, petAvatar),
      ('柴犬圈', Icons.pets, generatedPetImage),
      (
        '猫咪圈',
        Icons.pets,
        'https://images.unsplash.com/photo-1574158622682-e40e69881006?auto=format&fit=crop&w=300&q=80',
      ),
      (
        '救助站',
        Icons.volunteer_activism,
        'https://images.unsplash.com/photo-1548199973-03cce0bbc87b?auto=format&fit=crop&w=300&q=80',
      ),
    ];
    return SizedBox(
      height: 86,
      child: ListView.separated(
        scrollDirection: Axis.horizontal,
        itemCount: stories.length,
        separatorBuilder: (_, _) => const SizedBox(width: 16),
        itemBuilder: (context, index) {
          final item = stories[index];
          return InkWell(
            onTap: index == 0 ? onCreate : null,
            borderRadius: BorderRadius.circular(36),
            child: SizedBox(
              width: 62,
              child: Column(
                children: [
                  Container(
                    width: 58,
                    height: 58,
                    padding: const EdgeInsets.all(2),
                    decoration: const BoxDecoration(
                      shape: BoxShape.circle,
                      gradient: AppColors.brandGradient,
                    ),
                    child: index == 0
                        ? const CircleAvatar(
                            backgroundColor: Colors.white,
                            child: Icon(Icons.add, color: AppColors.primary),
                          )
                        : RemoteImage(
                            url: item.$3,
                            borderRadius: BorderRadius.circular(28),
                          ),
                  ),
                  const SizedBox(height: 5),
                  Text(
                    item.$1,
                    maxLines: 1,
                    style: Theme.of(context).textTheme.bodySmall,
                  ),
                ],
              ),
            ),
          );
        },
      ),
    );
  }
}

class _PromoCard extends StatelessWidget {
  const _PromoCard({required this.onTap});

  final VoidCallback onTap;

  @override
  Widget build(BuildContext context) {
    return Container(
      padding: const EdgeInsets.all(20),
      decoration: BoxDecoration(
        // 深端在左承载白字（4.5:1 达标）；brandGradient 不承载正文文字（FIX-1）。
        gradient: const LinearGradient(
          colors: [AppColors.primaryStrong, AppColors.primary],
        ),
        borderRadius: BorderRadius.circular(26),
      ),
      child: Row(
        children: [
          const Expanded(
            child: Column(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Text(
                  '新用户首单立减 ¥20',
                  style: TextStyle(
                    color: Colors.white,
                    fontSize: 18,
                    fontWeight: FontWeight.w800,
                  ),
                ),
                SizedBox(height: 5),
                Text(
                  '遛狗 / 洗澡 / 寄养均可使用',
                  style: TextStyle(color: Colors.white, fontSize: 12),
                ),
              ],
            ),
          ),
          FilledButton(
            style: FilledButton.styleFrom(
              backgroundColor: Colors.white,
              foregroundColor: AppColors.primaryStrong,
            ),
            onPressed: onTap,
            child: const Text('去使用'),
          ),
        ],
      ),
    );
  }
}

class _CategoryGrid extends StatelessWidget {
  const _CategoryGrid({required this.onTap});

  final ValueChanged<String> onTap;

  static const items = [
    ('投喂', Icons.restaurant),
    ('遛狗', Icons.directions_walk),
    ('洗澡', Icons.bathtub_outlined),
    ('美容', Icons.content_cut),
    ('寄养', Icons.home_outlined),
    ('运输', Icons.local_shipping_outlined),
    ('领养', Icons.favorite_border),
    ('医院', Icons.local_hospital_outlined),
  ];

  @override
  Widget build(BuildContext context) {
    return SectionCard(
      child: GridView.count(
        crossAxisCount: 4,
        shrinkWrap: true,
        physics: const NeverScrollableScrollPhysics(),
        mainAxisSpacing: 18,
        crossAxisSpacing: 8,
        childAspectRatio: .9,
        children: items.map((item) {
          return InkWell(
            onTap: () => onTap(item.$1),
            borderRadius: BorderRadius.circular(18),
            child: Column(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                CircleAvatar(
                  backgroundColor: AppColors.surfaceTint,
                  child: Icon(item.$2, color: AppColors.primary),
                ),
                const SizedBox(height: 7),
                Text(item.$1, style: Theme.of(context).textTheme.bodySmall),
              ],
            ),
          );
        }).toList(),
      ),
    );
  }
}

class _ProviderCompactCard extends StatelessWidget {
  const _ProviderCompactCard({required this.provider, required this.onTap});

  final ServiceProviderModel provider;
  final VoidCallback onTap;

  @override
  Widget build(BuildContext context) {
    return SectionCard(
      padding: const EdgeInsets.all(12),
      child: InkWell(
        onTap: onTap,
        borderRadius: BorderRadius.circular(18),
        child: Row(
          children: [
            RemoteImage(
              url: provider.image,
              width: 82,
              height: 82,
              borderRadius: BorderRadius.circular(17),
            ),
            const SizedBox(width: 12),
            Expanded(
              child: Column(
                crossAxisAlignment: CrossAxisAlignment.start,
                children: [
                  Text(
                    provider.name,
                    maxLines: 1,
                    overflow: TextOverflow.ellipsis,
                    style: const TextStyle(fontWeight: FontWeight.w800),
                  ),
                  const SizedBox(height: 4),
                  Text(
                    '${provider.distance} · ⭐ ${provider.rating}',
                    style: Theme.of(context).textTheme.bodySmall,
                  ),
                  const SizedBox(height: 7),
                  Text(
                    '¥${provider.price} 起',
                    style: const TextStyle(
                      color: AppColors.primary,
                      fontWeight: FontWeight.w800,
                    ),
                  ),
                ],
              ),
            ),
            const Icon(Icons.chevron_right, color: AppColors.muted),
          ],
        ),
      ),
    );
  }
}