import 'package:flutter/material.dart';
import 'package:flutter_riverpod/flutter_riverpod.dart';
import 'package:go_router/go_router.dart';

import '../../core/app_settings.dart';
import '../../core/chat_socket.dart';
import '../../core/fcm_service.dart';
import '../../core/msn_api.dart';
import '../../core/session_controller.dart';
import '../../theme/toss_theme.dart';
import 'context_members_tab.dart';
import 'home_providers.dart';
import 'my_profile_tab.dart';

class HomePage extends ConsumerStatefulWidget {
  const HomePage({super.key});

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

class _HomePageState extends ConsumerState<HomePage> {
  int _tabIndex = 0;

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) async {
      await ref.read(chatSocketProvider).connect();
      if (await readNotificationsEnabledFromPrefs()) {
        try {
          await initializeFcmAndLocalNotifications(ref.read(msnApiProvider));
        } catch (e, st) {
          debugPrint('FCM init: $e\n$st');
        }
      }
    });
  }

  Future<void> _onRefresh() async {
    ref.invalidate(contextsListProvider);
    final cid = ref.read(sessionProvider).value?.effectiveContextId;
    if (cid != null) {
      ref.invalidate(roomsForContextProvider(cid));
      ref.invalidate(membersForContextProvider(cid));
      ref.invalidate(myProfileForContextProvider(cid));
    }
    await ref.read(contextsListProvider.future);
    if (cid != null) {
      await ref.read(roomsForContextProvider(cid).future);
    }
  }

  Future<void> _pickContext(String? id) async {
    if (id == null) return;
    await ref.read(sessionProvider.notifier).setSelectedContext(id);
    setState(() {});
  }

  IconData _iconForKind(String kind) {
    switch (kind) {
      case 'work':
        return Icons.business_outlined;
      case 'personal':
        return Icons.home_outlined;
      default:
        return Icons.folder_outlined;
    }
  }

  Future<void> _addWorkContext() async {
    final name = TextEditingController();
    final ok = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        title: const Text('New work context'),
        content: TextField(
          controller: name,
          decoration: const InputDecoration(labelText: 'Name'),
        ),
        actions: [
          TextButton(onPressed: () => Navigator.pop(ctx, false), child: const Text('Cancel')),
          FilledButton(onPressed: () => Navigator.pop(ctx, true), child: const Text('Create')),
        ],
      ),
    );
    if (ok == true && name.text.trim().isNotEmpty) {
      await ref.read(msnApiProvider).createContext(name: name.text.trim(), kind: 'work');
      ref.invalidate(contextsListProvider);
    }
    name.dispose();
  }

  Future<void> _inviteEmail() async {
    final session = ref.read(sessionProvider).value;
    final cid = session?.effectiveContextId;
    if (cid == null) return;
    final email = TextEditingController();
    final ok = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        title: const Text('Invite by email'),
        content: TextField(
          controller: email,
          decoration: const InputDecoration(labelText: 'Email'),
        ),
        actions: [
          TextButton(onPressed: () => Navigator.pop(ctx, false), child: const Text('Cancel')),
          FilledButton(onPressed: () => Navigator.pop(ctx, true), child: const Text('Invite')),
        ],
      ),
    );
    if (ok == true && email.text.trim().isNotEmpty) {
      try {
        await ref.read(msnApiProvider).inviteToContext(cid, email.text.trim());
        ref.invalidate(membersForContextProvider(cid));
        if (!mounted) return;
        ScaffoldMessenger.of(context).showSnackBar(const SnackBar(content: Text('Invited')));
      } catch (e) {
        if (!mounted) return;
        ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text('$e')));
      }
    }
    email.dispose();
  }

  Future<void> _openDirect() async {
    final session = ref.read(sessionProvider).value;
    final cid = session?.effectiveContextId;
    if (cid == null) return;
    final uid = TextEditingController();
    final ok = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        title: const Text('Open direct chat'),
        content: TextField(
          controller: uid,
          decoration: const InputDecoration(labelText: 'Other user ID (UUID)'),
        ),
        actions: [
          TextButton(onPressed: () => Navigator.pop(ctx, false), child: const Text('Cancel')),
          FilledButton(onPressed: () => Navigator.pop(ctx, true), child: const Text('Open')),
        ],
      ),
    );
    if (ok == true && uid.text.trim().isNotEmpty) {
      final roomId = await ref.read(msnApiProvider).openDirectRoom(cid, uid.text.trim());
      if (!mounted) return;
      await context.push('/chat?roomId=$roomId&contextId=$cid');
    }
    uid.dispose();
  }

  Future<void> _createGroup() async {
    final session = ref.read(sessionProvider).value;
    final cid = session?.effectiveContextId;
    if (cid == null) return;
    final name = TextEditingController();
    final ok = await showDialog<bool>(
      context: context,
      builder: (ctx) => AlertDialog(
        title: const Text('New group'),
        content: TextField(
          controller: name,
          decoration: const InputDecoration(labelText: 'Group name'),
        ),
        actions: [
          TextButton(onPressed: () => Navigator.pop(ctx, false), child: const Text('Cancel')),
          FilledButton(onPressed: () => Navigator.pop(ctx, true), child: const Text('Create')),
        ],
      ),
    );
    if (ok == true && name.text.trim().isNotEmpty) {
      await ref.read(msnApiProvider).createGroupRoom(cid, name.text.trim(), []);
      ref.invalidate(roomsForContextProvider(cid));
    }
    name.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final session = ref.watch(sessionProvider).value;
    final cid = session?.effectiveContextId;
    final contextsAsync = ref.watch(contextsListProvider);

    const tabTitles = ['채팅', '친구', '내 정보'];

    return Scaffold(
      backgroundColor: TossColors.bg,
      appBar: AppBar(
        title: Text(tabTitles[_tabIndex.clamp(0, tabTitles.length - 1)]),
        actions: [
          IconButton(
            icon: const Icon(Icons.search),
            onPressed: cid == null ? null : () => context.push('/search?contextId=$cid'),
          ),
          PopupMenuButton<String>(
            onSelected: (v) async {
              if (v == 'settings') await context.push('/settings');
              if (v == 'logout') {
                await ref.read(chatSocketProvider).disconnect();
                await ref.read(sessionProvider.notifier).logout();
              }
              if (v == 'work') await _addWorkContext();
              if (v == 'invite') await _inviteEmail();
              if (v == 'group') await _createGroup();
            },
            itemBuilder: (context) => const [
              PopupMenuItem(value: 'settings', child: Text('설정')),
              PopupMenuItem(value: 'work', child: Text('직장 맥락 추가')),
              PopupMenuItem(value: 'invite', child: Text('이 맥락에 초대')),
              PopupMenuItem(value: 'group', child: Text('그룹 만들기')),
              PopupMenuItem(value: 'logout', child: Text('로그아웃')),
            ],
          ),
        ],
      ),
      body: contextsAsync.when(
        loading: () => const Center(child: CircularProgressIndicator(color: TossColors.blue)),
        error: (e, _) => Center(child: Text('Contexts: $e')),
        data: (list) {
          final effective = cid != null && list.any((c) => c.id == cid)
              ? cid
              : (list.isNotEmpty ? list.first.id : null);

          return Column(
            crossAxisAlignment: CrossAxisAlignment.stretch,
            children: [
              Padding(
                padding: const EdgeInsets.fromLTRB(16, 12, 16, 8),
                child: Column(
                  crossAxisAlignment: CrossAxisAlignment.start,
                  children: [
                    Text(
                      '메신저 공간',
                      style: Theme.of(context).textTheme.titleMedium,
                    ),
                    const SizedBox(height: 4),
                    Text(
                      '선택한 공간의 대화·친구·프로필이에요. 탭해서 일상 · 직장을 전환하세요',
                      style: Theme.of(context).textTheme.bodySmall,
                    ),
                    const SizedBox(height: 14),
                    SizedBox(
                      height: 46,
                      child: ListView.separated(
                        scrollDirection: Axis.horizontal,
                        itemCount: list.length,
                        separatorBuilder: (_, __) => const SizedBox(width: 8),
                        itemBuilder: (context, i) {
                          final c = list[i];
                          final selected = effective == c.id;
                          return _TossContextChip(
                            label: c.name,
                            icon: _iconForKind(c.kind),
                            selected: selected,
                            onTap: () => _pickContext(c.id),
                          );
                        },
                      ),
                    ),
                  ],
                ),
              ),
              Expanded(
                child: effective == null
                    ? const Center(child: Text('맥락이 없습니다'))
                    : IndexedStack(
                        index: _tabIndex,
                        children: [
                          RefreshIndicator(
                            onRefresh: _onRefresh,
                            child: CustomScrollView(
                              physics: const AlwaysScrollableScrollPhysics(),
                              slivers: _roomSlivers(context, effective),
                            ),
                          ),
                          ContextMembersTab(contextId: effective),
                          const MyProfileTab(),
                        ],
                      ),
              ),
            ],
          );
        },
      ),
      bottomNavigationBar: NavigationBar(
        selectedIndex: _tabIndex,
        onDestinationSelected: (i) => setState(() => _tabIndex = i),
        destinations: const [
          NavigationDestination(
            icon: Icon(Icons.chat_bubble_outline),
            selectedIcon: Icon(Icons.chat_bubble),
            label: '채팅',
          ),
          NavigationDestination(
            icon: Icon(Icons.people_outline),
            selectedIcon: Icon(Icons.people),
            label: '친구',
          ),
          NavigationDestination(
            icon: Icon(Icons.person_outline),
            selectedIcon: Icon(Icons.person),
            label: '내 정보',
          ),
        ],
      ),
      floatingActionButton: _tabIndex == 0
          ? FloatingActionButton(
              onPressed: _openDirect,
              child: const Icon(Icons.chat_bubble_outline),
            )
          : null,
    );
  }

  List<Widget> _roomSlivers(BuildContext context, String effectiveContextId) {
    final asyncRooms = ref.watch(roomsForContextProvider(effectiveContextId));

    return asyncRooms.when(
      loading: () => [
        const SliverFillRemaining(
          hasScrollBody: false,
          child: Center(child: CircularProgressIndicator(color: TossColors.blue)),
        ),
      ],
      error: (e, _) => [
        SliverFillRemaining(
          hasScrollBody: false,
          child: Center(child: Text('$e')),
        ),
      ],
      data: (rooms) {
        if (rooms.isEmpty) {
          return [
            SliverFillRemaining(
              hasScrollBody: false,
              child: Center(
                child: Column(
                  mainAxisSize: MainAxisSize.min,
                  children: [
                    Icon(Icons.chat_outlined, size: 48, color: Theme.of(context).disabledColor),
                    const SizedBox(height: 12),
                    Text(
                      '대화가 없습니다',
                      style: Theme.of(context).textTheme.titleSmall,
                    ),
                    const SizedBox(height: 4),
                    Text(
                      '+ 버튼으로 직접 대화를 열 수 있습니다',
                      style: Theme.of(context).textTheme.bodySmall,
                    ),
                  ],
                ),
              ),
            ),
          ];
        }
        return [
          SliverPadding(
            padding: const EdgeInsets.fromLTRB(16, 0, 16, 100),
            sliver: SliverList(
              delegate: SliverChildBuilderDelegate(
                (context, i) {
                  final r = rooms[i];
                  final subtitle = r.lastBody ?? '메시지 없음';
                  final time = r.lastAt;
                  return Padding(
                    padding: const EdgeInsets.only(bottom: 10),
                    child: Material(
                      color: TossColors.surface,
                      borderRadius: BorderRadius.circular(16),
                      elevation: 0,
                      shadowColor: Colors.black.withValues(alpha: 0.06),
                      child: InkWell(
                        borderRadius: BorderRadius.circular(16),
                        onTap: () => context.push(
                          '/chat?roomId=${r.id}&contextId=$effectiveContextId',
                        ),
                        child: Ink(
                          decoration: BoxDecoration(
                            borderRadius: BorderRadius.circular(16),
                            border: Border.all(color: TossColors.line),
                          ),
                          child: Padding(
                            padding: const EdgeInsets.symmetric(horizontal: 14, vertical: 14),
                            child: Row(
                              children: [
                                CircleAvatar(
                                  radius: 22,
                                  backgroundColor: TossColors.blue.withValues(alpha: 0.1),
                                  child: Icon(
                                    r.isGroup ? Icons.groups_rounded : Icons.person_rounded,
                                    color: TossColors.blue,
                                    size: 24,
                                  ),
                                ),
                                const SizedBox(width: 14),
                                Expanded(
                                  child: Column(
                                    crossAxisAlignment: CrossAxisAlignment.start,
                                    children: [
                                      Text(
                                        r.name ?? (r.isGroup ? '그룹 채팅' : '1:1 채팅'),
                                        style: Theme.of(context).textTheme.titleMedium,
                                        maxLines: 1,
                                        overflow: TextOverflow.ellipsis,
                                      ),
                                      const SizedBox(height: 4),
                                      Text(
                                        subtitle,
                                        style: Theme.of(context).textTheme.bodySmall,
                                        maxLines: 2,
                                        overflow: TextOverflow.ellipsis,
                                      ),
                                    ],
                                  ),
                                ),
                                if (time != null && time.isNotEmpty)
                                  Text(
                                    _shortTime(time),
                                    style: Theme.of(context).textTheme.bodySmall?.copyWith(
                                          fontWeight: FontWeight.w500,
                                        ),
                                  ),
                              ],
                            ),
                          ),
                        ),
                      ),
                    ),
                  );
                },
                childCount: rooms.length,
              ),
            ),
          ),
        ];
      },
    );
  }

  String _shortTime(String iso) {
    try {
      final d = DateTime.tryParse(iso);
      if (d == null) return '';
      final now = DateTime.now();
      if (d.year == now.year && d.month == now.month && d.day == now.day) {
        return '${d.hour.toString().padLeft(2, '0')}:${d.minute.toString().padLeft(2, '0')}';
      }
      return '${d.month}/${d.day}';
    } catch (_) {
      return '';
    }
  }
}

/// Pill chip: Toss blue when selected, white + border otherwise.
class _TossContextChip extends StatelessWidget {
  const _TossContextChip({
    required this.label,
    required this.icon,
    required this.selected,
    required this.onTap,
  });

  final String label;
  final IconData icon;
  final bool selected;
  final VoidCallback onTap;

  @override
  Widget build(BuildContext context) {
    return Material(
      color: selected ? TossColors.blue : TossColors.surface,
      borderRadius: BorderRadius.circular(24),
      child: InkWell(
        onTap: onTap,
        borderRadius: BorderRadius.circular(24),
        child: Container(
          padding: const EdgeInsets.symmetric(horizontal: 14, vertical: 10),
          decoration: BoxDecoration(
            borderRadius: BorderRadius.circular(24),
            border: Border.all(
              color: selected ? TossColors.blue : TossColors.line,
              width: selected ? 0 : 1,
            ),
          ),
          child: Row(
            mainAxisSize: MainAxisSize.min,
            children: [
              Icon(
                icon,
                size: 18,
                color: selected ? Colors.white : TossColors.textSecondary,
              ),
              const SizedBox(width: 6),
              Text(
                label,
                style: TextStyle(
                  fontWeight: FontWeight.w600,
                  fontSize: 14,
                  color: selected ? Colors.white : TossColors.textPrimary,
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}