import 'package:flutter/material.dart';
import 'package:flutter_localizations/flutter_localizations.dart';

import '../domain/schedule_engine.dart';
import '../features/timetable/course_details.dart';

import 'app_controller.dart';
import 'app_theme.dart';
import '../widgets/glass_dock.dart';
import '../widgets/tab_deck.dart';
import '../features/exams/exams_page.dart';
import '../features/timetable/timetable_page.dart';
import '../features/profile/profile_page.dart';
import '../features/school/school_session.dart';

class HepanApp extends StatelessWidget {
  const HepanApp({
    super.key,
    required this.controller,
    this.schoolBuilder,
    this.school,
    this.notificationSelection,
  });
  final AppController controller;
  final Widget Function()? schoolBuilder;
  final SchoolSession? school;
  final ValueNotifier<String?>? notificationSelection;
  @override
  Widget build(BuildContext context) => MaterialApp(
    debugShowCheckedModeBanner: false,
    title: 'RSchedule',
    theme: hepanTheme(),
    locale: const Locale('zh', 'CN'),
    supportedLocales: const [Locale('zh', 'CN')],
    localizationsDelegates: GlobalMaterialLocalizations.delegates,
    home: _Shell(
      controller: controller,
      schoolBuilder: schoolBuilder,
      school: school,
      notificationSelection: notificationSelection,
    ),
  );
}

class _Shell extends StatefulWidget {
  const _Shell({
    required this.controller,
    this.schoolBuilder,
    this.school,
    this.notificationSelection,
  });
  final AppController controller;
  final Widget Function()? schoolBuilder;
  final SchoolSession? school;
  final ValueNotifier<String?>? notificationSelection;
  @override
  State<_Shell> createState() => _ShellState();
}

class _ShellState extends State<_Shell> with WidgetsBindingObserver {
  int _tab = 0;
  bool _dockHidden = false;
  double _scrollTravel = 0;
  void _selectTab(int index) {
    if (index == _tab) return;
    setState(() {
      _tab = index;
      _dockHidden = false;
      _scrollTravel = 0;
    });
  }

  bool _scroll(ScrollNotification notification) {
    if (_tab == 2 || notification.metrics.axis != Axis.vertical) return false;
    if (notification is ScrollUpdateNotification &&
        notification.dragDetails != null) {
      final delta = notification.scrollDelta ?? 0;
      if (delta.sign != _scrollTravel.sign) _scrollTravel = 0;
      _scrollTravel += delta;
      final hide = notification.metrics.pixels > 0 && _scrollTravel > 24;
      final reveal = notification.metrics.pixels <= 0 || _scrollTravel < -16;
      if ((hide && !_dockHidden) || (reveal && _dockHidden)) {
        setState(() => _dockHidden = hide);
      }
    }
    return false;
  }

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addObserver(this);
    widget.notificationSelection?.addListener(_selectNotification);
    WidgetsBinding.instance.addPostFrameCallback((_) => _selectNotification());
  }

  @override
  void dispose() {
    WidgetsBinding.instance.removeObserver(this);
    widget.notificationSelection?.removeListener(_selectNotification);
    super.dispose();
  }

  Future<void> _selectNotification() async {
    final key = widget.notificationSelection?.value;
    if (key == null || !mounted) {
      return;
    }
    widget.notificationSelection!.value = null;
    await widget.controller.leaveDemo();
    if (!mounted) {
      return;
    }
    Navigator.of(context).popUntil((route) => route.isFirst);
    setState(() => _tab = 0);
    final semester = widget.controller.snapshot.settings.semester;
    if (semester == null) {
      return;
    }
    final events = ScheduleEngine.occurrences(
      widget.controller.snapshot.courses,
      semester,
    ).where((e) => e.key == key);
    if (events.isNotEmpty) {
      showCourseDetails(context, events.first);
    } else {
      ScaffoldMessenger.of(context)
          .showSnackBar(const SnackBar(content: Text('这门课程已更新，请查看当前课表')));
    }
  }

  @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
    if (state == AppLifecycleState.resumed) {
      widget.controller.refreshServices();
    }
  }

  void _school({bool exams = false}) {
    if (widget.schoolBuilder != null) {
      if (exams) {
        widget.school?.openExams();
      } else {
        widget.school?.openTimetable();
      }
      Navigator.push(
        context,
        MaterialPageRoute<void>(builder: (_) => widget.schoolBuilder!()),
      );
    } else {
      showDialog<void>(
        context: context,
        builder: (context) => AlertDialog(
          title: const Text('学校认证'),
          content: const Text('学校认证入口正在接入。你可以先体验示例课表或导入课表文件。'),
          actions: [
            TextButton(
              onPressed: () => Navigator.pop(context),
              child: const Text('知道了'),
            ),
          ],
        ),
      );
    }
  }

  Future<void> _logout() async {
    final choice = await showDialog<int>(
      context: context,
      builder: (context) => AlertDialog(
        title: const Text('退出学校登录'),
        content: const Text('已导入的课表和考试信息是否保留在手机中？'),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context, 0),
            child: const Text('取消'),
          ),
          TextButton(
            onPressed: () => Navigator.pop(context, 1),
            child: const Text('保留课表和考试'),
          ),
          TextButton(
            onPressed: () => Navigator.pop(context, 2),
            child: const Text('清除课表和考试'),
          ),
        ],
      ),
    );
    if (choice == null || choice == 0) return;
    await widget.school?.logout();
    if (choice == 2) {
      await widget.controller.clearCourses();
      await widget.controller.clearExams();
    }
  }

  Future<void> _startFresh() async {
    final confirmed = await showDialog<bool>(
      context: context,
      builder: (context) => AlertDialog(
        title: const Text('重新建立课表'),
        content: const Text(
          '损坏文件会保留为恢复副本，然后重新建立空课表。已有课程通知会取消；手机日历中原有课程日程需手动处理。',
        ),
        actions: [
          TextButton(
            onPressed: () => Navigator.pop(context, false),
            child: const Text('取消'),
          ),
          FilledButton(
            onPressed: () => Navigator.pop(context, true),
            child: const Text('保留损坏文件并重新建立'),
          ),
        ],
      ),
    );
    if (confirmed == true) {
      await widget.controller.startFreshData();
    }
  }

  @override
  Widget build(BuildContext context) => AnimatedBuilder(
    animation: Listenable.merge([
      widget.controller,
      if (widget.school != null) widget.school!,
    ]),
    builder: (context, _) => Scaffold(
      body: Container(
        decoration: const BoxDecoration(
          gradient: LinearGradient(
            begin: Alignment.topLeft,
            end: Alignment.bottomRight,
            colors: [Color(0xFFF0F7F5), Color(0xFFF7F8F5), Color(0xFFEFF5F3)],
          ),
        ),
        child: SafeArea(
          bottom: false,
          child: Stack(
            children: [
              Positioned.fill(
                child: Column(
                  children: [
                    if (widget.controller.lastError != null)
                      Container(
                        width: double.infinity,
                        color: const Color(0xFFF8ECE6),
                        padding: const EdgeInsets.all(12),
                        child: Column(
                          crossAxisAlignment: CrossAxisAlignment.start,
                          children: [
                            Text(
                              widget.controller.lastError!,
                              style: const TextStyle(fontSize: 12),
                            ),
                            if (!widget.controller.storageReady)
                              TextButton(
                                onPressed: widget.controller.restoreBackup,
                                child: const Text('恢复最近备份'),
                              ),
                            if (!widget.controller.storageReady)
                              TextButton(
                                onPressed: _startFresh,
                                child: const Text('重新建立课表'),
                              ),
                          ],
                        ),
                      ),
                    Expanded(
                      child: NotificationListener<ScrollNotification>(
                        onNotification: _scroll,
                        child: TabDeck(
                          index: _tab,
                          children: [
                            TimetablePage(controller: widget.controller),
                            ExamsPage(
                              controller: widget.controller,
                              onSync: () {
                                _school(exams: true);
                              },
                            ),
                            ProfilePage(
                              controller: widget.controller,
                              onLogin: _school,
                              authStatus: widget.school?.statusLabel ?? '未登录',
                              logoutLabel: widget.school?.logoutFailed == true
                                  ? '重试退出学校登录'
                                  : '退出学校登录',
                              onLogout: widget.school?.canLogout == true
                                  ? _logout
                                  : null,
                            ),
                          ],
                        ),
                      ),
                    ),
                  ],
                ),
              ),
              Positioned(
                left: 0,
                right: 0,
                bottom: 16 + MediaQuery.paddingOf(context).bottom,
                child: Center(
                  child: IgnorePointer(
                    ignoring: _dockHidden,
                    child: ExcludeSemantics(
                      excluding: _dockHidden,
                      child: AnimatedSlide(
                        key: const Key('floating-dock'),
                        offset: _dockHidden
                            ? const Offset(0, 1.8)
                            : Offset.zero,
                        duration: MediaQuery.disableAnimationsOf(context)
                            ? Duration.zero
                            : const Duration(milliseconds: 240),
                        curve: Curves.easeOutCubic,
                        child: AnimatedOpacity(
                          opacity: _dockHidden ? 0 : 1,
                          duration: const Duration(milliseconds: 180),
                          child: GlassDock(
                            selectedIndex: _tab,
                            onSelected: _selectTab,
                          ),
                        ),
                      ),
                    ),
                  ),
                ),
              ),
            ],
          ),
        ),
      ),
    ),
  );
}