import 'dart:ui';
import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';

void main() async {
  runApp(const MyApp());
}

class MyApp extends StatefulWidget {
  const MyApp({super.key});

  @override
  State<MyApp> createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  bool isDark = false;

  void switchBrightness() {
    setState(() {
      isDark = !isDark;
    });
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Bug',
      scrollBehavior: CustomScrollBehavior(),
      theme: ThemeData(
        colorScheme: ColorScheme.fromSeed(
          seedColor: Color(0xff6750a4),
          brightness: !isDark ? Brightness.light : Brightness.dark,
          dynamicSchemeVariant: DynamicSchemeVariant.tonalSpot,
        ),
        useMaterial3: true,
      ),
      debugShowCheckedModeBanner: false,
      home: PageNavigator(onBrightnessChange: switchBrightness),
      // home: MainScreen(onBrightnessChange: switchBrightness),
    );
  }
}

class PageNavigator extends StatefulWidget {
  const PageNavigator({super.key, required this.onBrightnessChange});

  final VoidCallback onBrightnessChange;

  @override
  State<PageNavigator> createState() => _PageNavigatorState();
}

class _PageNavigatorState extends State<PageNavigator> {
  late int currentPageIndex = 0;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      bottomNavigationBar: NavigationBar(
        onDestinationSelected: (int index) {
          if (currentPageIndex != index) {
            setState(() {
              currentPageIndex = index;
            });
          }
        },
        selectedIndex: currentPageIndex,
        destinations: <Widget>[
          NavigationDestination(
            icon: Icon(Icons.home),
            label: 'Main',
            tooltip: '',
          ),
          NavigationDestination(
            icon: Icon(Icons.date_range_rounded),
            label: 'Daily',
            tooltip: '',
          ),
        ],
      ),
      body: [
        MainScreen(onBrightnessChange: widget.onBrightnessChange), // main
        Container(), // daily
      ][currentPageIndex],
    );
  }
}

class MainScreen extends StatefulWidget {
  const MainScreen({super.key, required this.onBrightnessChange});

  final VoidCallback onBrightnessChange;

  @override
  State<MainScreen> createState() => _MainScreenState();
}

class _MainScreenState extends State<MainScreen> {
  final List<String> tabs = <String>[
    'All',
    'New',
    "Books",
    "Anime",
    "Sport",
    "Movies",
    "Flowers",
    "Games",
  ];

  @override
  Widget build(BuildContext context) {
    // var colorScheme = Theme.of(context).colorScheme;
    return DefaultTabController(
      length: tabs.length,
      child: Scaffold(
        body: NestedScrollView(
          floatHeaderSlivers: true,
          headerSliverBuilder: (BuildContext context, bool innerBoxIsScrolled) {
            return [
              SliverOverlapAbsorber(
                handle: NestedScrollView.sliverOverlapAbsorberHandleFor(
                  context,
                ),
                sliver: SliverAppBar(
                  title: Text(
                    'Main',
                    style: TextStyle(fontWeight: FontWeight.bold),
                  ),
                  centerTitle: false,
                  pinned: true,
                  forceElevated: innerBoxIsScrolled,
                ),
              ),
              SliverPersistentHeader(
                pinned: true,
                delegate: _SliverTabBarDelegate(
                  TabBar(
                    onTap: (_) {},
                    tabs: tabs.map((String name) => Tab(text: name)).toList(),
                    isScrollable: true,
                    tabAlignment: TabAlignment.start,
                    labelStyle: Theme.of(context).textTheme.titleMedium
                        ?.copyWith(
                          color: Theme.of(context).colorScheme.primary,
                          fontWeight: FontWeight.bold,
                        ),
                    dividerHeight: 0,
                  ),
                ),
              ),
            ];
          },
          body: TabBarView(
            children: [
              for (int i = 0; i < tabs.length; ++i)
                Center(
                  child: FilledButton(
                    onPressed: () {
                      widget.onBrightnessChange.call();
                    },
                    child: Text('Switch'),
                  ),
                ),
            ],
          ),
        ),
      ),
    );
  }
}

// class CustomScrollBehavior extends MaterialScrollBehavior {
// class CustomScrollBehavior extends CupertinoScrollBehavior {
class CustomScrollBehavior extends ScrollBehavior {
  @override
  Set<PointerDeviceKind> get dragDevices => const {...PointerDeviceKind.values};
}

class _SliverTabBarDelegate extends SliverPersistentHeaderDelegate {
  _SliverTabBarDelegate(this.tabBar);
  final TabBar tabBar;

  @override
  Widget build(
    BuildContext context,
    double shrinkOffset,
    bool overlapsContent,
  ) {
    print('rebuild');
    return Container(
      color: Theme.of(context).colorScheme.surface,
      padding: EdgeInsets.symmetric(horizontal: 8),
      child: Stack(
        children: [
          Row(
            children: [
              Expanded(child: tabBar),
              SizedBox(width: 4),
              IconButton(icon: Icon(Icons.menu), onPressed: () {}),
            ],
          ),
          Align(
            alignment: Alignment.bottomCenter,
            child: Divider(height: 1, thickness: 1),
          ),
        ],
      ),
    );
  }

  @override
  double get maxExtent => tabBar.preferredSize.height;

  @override
  double get minExtent => tabBar.preferredSize.height;

  @override
  bool shouldRebuild(SliverPersistentHeaderDelegate oldDelegate) {
    return false;
  }
}