import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';
import 'package:tdesign_flutter/tdesign_flutter.dart';
import 'package:easy_refresh/easy_refresh.dart';
import '../../core/theme/app_colors.dart';
import '../shell/nav_bar_config.dart';
import '../../core/utils/date_utils.dart' as du;
import '../../core/utils/responsive.dart';
import '../../shared/widgets/empty_state.dart';
import '../../core/i18n/app_localizations.dart';
import 'announcement_list_controller.dart';
import 'announcement_model.dart';

class AnnouncementListPage extends ConsumerStatefulWidget {
  const AnnouncementListPage({super.key});
  @override
  ConsumerState<AnnouncementListPage> createState() =>
      _AnnouncementListPageState();
}

class _AnnouncementListPageState extends ConsumerState<AnnouncementListPage>
    with TickerProviderStateMixin {
  late TabController _tabCtrl;

  static List<String> _getTabLabels(bool isAdmin) => isAdmin
      ? ['全部', '通知公告', '人事与制度', '放假与活动', '我的草稿']
      : ['全部', '通知公告', '人事与制度', '放假与活动'];

  @override
  void initState() {
    super.initState();
    final isAdmin = ref.read(isAdminProvider);
    _tabCtrl = TabController(
      length: _getTabLabels(isAdmin).length,
      vsync: this,
    );
    _tabCtrl.addListener(_onTabChanged);
  }

  void _onTabChanged() {
    if (!_tabCtrl.indexIsChanging) {
      ref.read(announcementTabProvider.notifier).state = _tabCtrl.index;
    }
  }

  @override
  void dispose() {
    _tabCtrl.dispose();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final isAdmin = ref.watch(isAdminProvider);
    final tabs = _getTabLabels(isAdmin);
    final tabIndex = ref.watch(announcementTabProvider);
    final r = ResponsiveHelper.of(context);
    final l10n = AppLocalizations.of(context);

    // Handle TabController recreation when tab count changes (isAdmin toggle)
    if (_tabCtrl.length != tabs.length) {
      WidgetsBinding.instance.addPostFrameCallback((_) {
        if (!mounted) return;
        final newIdx = tabIndex >= tabs.length ? 0 : tabIndex;
        _tabCtrl.dispose();
        _tabCtrl = TabController(
          length: tabs.length,
          vsync: this,
          initialIndex: newIdx,
        );
        _tabCtrl.addListener(_onTabChanged);
        setState(() {});
      });
      // Render a simplified view during this frame to avoid length mismatch
      return Center(
        child: ConstrainedBox(
          constraints: BoxConstraints(maxWidth: r.listMaxWidth),
          child: Column(
            children: [
              Container(
                color: AppColors.bgCard,
                padding: const EdgeInsets.symmetric(horizontal: 8),
                child: TDTabBar(
                  tabs: tabs.map((l) => TDTab(text: l)).toList(),
                  isScrollable: true,
                  labelColor: AppColors.primary,
                  unselectedLabelColor: AppColors.textSecondary,
                  outlineType: TDTabBarOutlineType.filled,
                  showIndicator: true,
                  indicatorColor: AppColors.primary,
                  indicatorHeight: 3,
                  labelPadding: const EdgeInsets.symmetric(horizontal: 12),
                ),
              ),
              const Expanded(child: SizedBox.shrink()),
            ],
          ),
        ),
      );
    }

    // Sync TabController with external changes
    if (_tabCtrl.index != tabIndex && !_tabCtrl.indexIsChanging) {
      WidgetsBinding.instance.addPostFrameCallback((_) {
        if (mounted) _tabCtrl.animateTo(tabIndex);
      });
    }

    ref
        .read(navBarConfigProvider.notifier)
        .update(
          NavBarConfig(
            title: l10n.get('announcementList'),
            showBack: true,
            onBack: () => context.pop(),
          ),
        );
    return Center(
      child: ConstrainedBox(
        constraints: BoxConstraints(maxWidth: r.listMaxWidth),
        child: Column(
          children: [
            Container(
              color: AppColors.bgCard,
              padding: const EdgeInsets.symmetric(horizontal: 8),
              child: TDTabBar(
                tabs: tabs.map((l) => TDTab(text: l)).toList(),
                controller: _tabCtrl,
                isScrollable: true,
                labelColor: AppColors.primary,
                unselectedLabelColor: AppColors.textSecondary,
                outlineType: TDTabBarOutlineType.filled,
                showIndicator: true,
                indicatorColor: AppColors.primary,
                indicatorHeight: 3,
                labelPadding: const EdgeInsets.symmetric(horizontal: 12),
                onTap: (index) {
                  ref.read(announcementTabProvider.notifier).state = index;
                },
              ),
            ),
            Expanded(
              child: TabBarView(
                controller: _tabCtrl,
                children: List.generate(tabs.length, (tabIdx) {
                  return _AnnouncementTabContent(tabIndex: tabIdx);
                }),
              ),
            ),
          ],
        ),
      ),
    );
  }
}

class _AnnouncementTabContent extends ConsumerWidget {
  final int tabIndex;

  const _AnnouncementTabContent({required this.tabIndex});

  @override
  Widget build(BuildContext context, WidgetRef ref) {
    final items = ref.watch(filteredAnnouncementsProvider);

    if (items.isEmpty) {
      return EasyRefresh(
        header: TDRefreshHeader(),
        onRefresh: () async {
          ref.invalidate(filteredAnnouncementsProvider);
        },
        child: ListView(
          children: const [
            SizedBox(height: 120),
            EmptyState(message: '暂无行政公告'),
          ],
        ),
      );
    }

    return EasyRefresh(
      header: TDRefreshHeader(),
      onRefresh: () async {
        ref.invalidate(filteredAnnouncementsProvider);
      },
      child: ListView.builder(
        padding: const EdgeInsets.symmetric(vertical: 8),
        itemCount: items.length,
        itemBuilder: (_, i) => _buildAnnouncementCard(context, items[i]),
      ),
    );
  }

  Widget _buildAnnouncementCard(BuildContext context, AnnouncementModel item) {
    final expired = item.isExpired;
    return Padding(
      padding: const EdgeInsets.symmetric(horizontal: 16, vertical: 4),
      child: GestureDetector(
        onTap: () => context.push('/announcement/detail/${item.id}'),
        child: AnimatedContainer(
          duration: const Duration(milliseconds: 200),
          padding: const EdgeInsets.all(12),
          decoration: BoxDecoration(
            borderRadius: BorderRadius.circular(8),
            color: expired
                ? const Color(0xFFF9F9F9)
                : AppColors.bgCard,
          ),
          child: Column(
            crossAxisAlignment: CrossAxisAlignment.start,
            children: [
              // 标题行
              Row(
                children: [
                  // 置顶标记
                  if (item.isTop)
                    Container(
                      margin: const EdgeInsets.only(right: 6),
                      padding: const EdgeInsets.symmetric(
                          horizontal: 4, vertical: 1),
                      decoration: BoxDecoration(
                        color: AppColors.danger,
                        borderRadius: BorderRadius.circular(2),
                      ),
                      child: const Text('置顶',
                          style: TextStyle(
                              fontSize: 10, color: Colors.white)),
                    ),
                  // 标题
                  Expanded(
                    child: Text(
                      item.title,
                      maxLines: 1,
                      overflow: TextOverflow.ellipsis,
                      style: TextStyle(
                        fontSize: 15,
                        fontWeight: FontWeight.w600,
                        color: expired
                            ? AppColors.textPlaceholder
                            : AppColors.textPrimary,
                        decoration:
                            expired ? TextDecoration.lineThrough : null,
                      ),
                    ),
                  ),
                  // 已过期标记
                  if (expired)
                    Container(
                      margin: const EdgeInsets.only(left: 6),
                      padding: const EdgeInsets.symmetric(
                          horizontal: 6, vertical: 2),
                      decoration: BoxDecoration(
                        color: AppColors.bgPage,
                        borderRadius: BorderRadius.circular(3),
                      ),
                      child: const Text('已过期',
                          style: TextStyle(
                              fontSize: 10, color: AppColors.textPlaceholder)),
                    ),
                  // 未读红点
                  if (!item.isRead && !expired)
                    Container(
                      margin: const EdgeInsets.only(left: 6),
                      width: 8,
                      height: 8,
                      decoration: const BoxDecoration(
                        color: AppColors.danger,
                        shape: BoxShape.circle,
                      ),
                    ),
                ],
              ),
              const SizedBox(height: 8),
              // 元信息行
              Row(
                mainAxisAlignment: MainAxisAlignment.spaceBetween,
                children: [
                  Row(
                    children: [
                      _buildTypeTag(item.typeLabel),
                      const SizedBox(width: 8),
                      Text(
                        item.publisherName,
                        style: const TextStyle(
                            fontSize: 12, color: AppColors.textSecondary),
                      ),
                    ],
                  ),
                  Text(
                    du.DateUtils.formatDateTime(item.publishTime),
                    style: const TextStyle(
                        fontSize: 12, color: AppColors.textPlaceholder),
                  ),
                ],
              ),
            ],
          ),
        ),
      ),
    );
  }

  Widget _buildTypeTag(String type) {
    Color bgColor;
    Color textColor;
    switch (type) {
      case '人事与制度':
        bgColor = AppColors.successBg;
        textColor = AppColors.success;
        break;
      case '放假与活动':
        bgColor = AppColors.warningBg;
        textColor = AppColors.warning;
        break;
      default: // 通知公告
        bgColor = AppColors.primaryLight;
        textColor = AppColors.primary;
    }
    return Container(
      padding: const EdgeInsets.symmetric(horizontal: 6, vertical: 2),
      decoration: BoxDecoration(
        color: bgColor,
        borderRadius: BorderRadius.circular(3),
      ),
      child:
          Text(type, style: TextStyle(fontSize: 11, color: textColor)),
    );
  }
}