import 'dart:async';
import 'package:audio_service/audio_service.dart';
import 'package:flutter/material.dart';
import 'package:flutter/services.dart';
import 'package:freezer/api/definitions.dart';
import 'package:freezer/api/player.dart';
import 'package:freezer/translations.i18n.dart';
import 'package:freezer/ui/elements.dart';
import 'package:freezer/ui/player_screen.dart';
import 'package:freezer/ui/tiles.dart';

class QueueScreen extends StatefulWidget {
  @override
  _QueueScreenState createState() => _QueueScreenState();
}

class _QueueScreenState extends State<QueueScreen> {
  late StreamSubscription _queueSub;
  static const _dismissibleBackground = DecoratedBox(
      decoration: BoxDecoration(color: Colors.red),
      child: Align(
          child: Padding(
              padding: EdgeInsets.symmetric(horizontal: 24.0),
              child: Icon(Icons.delete)),
          alignment: Alignment.centerLeft));
  static const _dismissibleSecondaryBackground = DecoratedBox(
      decoration: BoxDecoration(color: Colors.red),
      child: Align(
          child: Padding(
              padding: EdgeInsets.symmetric(horizontal: 24.0),
              child: Icon(Icons.delete)),
          alignment: Alignment.centerRight));

  /// Basically a simple list that keeps itself synchronized with [AudioHandler.queue],
  /// so that the [ReorderableListView] is updated instanly (as it should be)
  List<MediaItem> _queueCache = [];

  @override
  void initState() {
    _queueCache = List.from(audioHandler.queue.value); // avoid shadow-copying
    _queueSub = audioHandler.queue.listen((newQueue) {
      print('got new queue!');
      // avoid rebuilding if the cache has got the right update
      // if (listEquals(_queueCache, newQueue)) {
      //   print('avoiding rebuilding queue since they are the same');
      //   return;
      // }
      setState(() => _queueCache = List.from(newQueue));
    });
    super.initState();
  }

  @override
  void dispose() {
    _queueSub.cancel();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: FreezerAppBar(
        'Queue'.i18n,
        systemUiOverlayStyle: SystemUiOverlayStyle(
          statusBarColor: Colors.transparent,
          statusBarIconBrightness: Brightness.light,
          statusBarBrightness: Brightness.light,
          systemNavigationBarColor: Theme.of(context).scaffoldBackgroundColor,
          systemNavigationBarDividerColor: Color(
              Theme.of(context).scaffoldBackgroundColor.value - 0x00111111),
          systemNavigationBarIconBrightness: Brightness.light,
        ),
        // actions: <Widget>[
        //   IconButton(
        //     icon: Icon(
        //       Icons.shuffle,
        //       semanticLabel: "Shuffle".i18n,
        //     ),
        //     onPressed: () async {
        //       await playerHelper.toggleShuffle();
        //       setState(() {});
        //     },
        //   )
        // ],
      ),
      body: SafeArea(
        child: ReorderableListView.builder(
          onReorder: (int oldIndex, int newIndex) {
            if (oldIndex == playerHelper.queueIndex) return;
            setState(() => _queueCache..reorder(oldIndex, newIndex));
            playerHelper.reorder(oldIndex, newIndex);
          },
          itemCount: _queueCache.length,
          itemBuilder: (BuildContext context, int i) {
            Track track = Track.fromMediaItem(audioHandler.queue.value[i]);
            return Dismissible(
              key: ValueKey<String>(track.id),
              background: _dismissibleBackground,
              secondaryBackground: _dismissibleSecondaryBackground,
              onDismissed: (_) {
                audioHandler.removeQueueItemAt(i);
                setState(() => _queueCache.removeAt(i));
              },
              confirmDismiss: (_) {
                if (i == playerHelper.queueIndex)
                  return audioHandler.skipToNext().then((value) => true);
                return Future.value(true);
                // final completer = Completer<bool>();
                // ScaffoldMessenger.of(context).clearSnackBars();
                // ScaffoldMessenger.of(context)
                //     .showSnackBar(SnackBar(
                //         behavior: SnackBarBehavior.floating,
                //         content: Text('Song deleted from queue'),
                //         action: SnackBarAction(
                //             label: 'UNDO',
                //             onPressed: () => completer.complete(false))))
                //     .closed
                //     .then((value) {
                //   if (value == SnackBarClosedReason.action) return;
                //   completer.complete(true);
                // });
                // return completer.future;
              },
              child: TrackTile(
                track,
                onTap: () {
                  pageViewLock = true;
                  audioHandler.skipToQueueItem(i).then((value) {
                    Navigator.of(context).pop();
                    pageViewLock = false;
                  });
                },
                key: Key(track.id),
              ),
            );
          },
        ),
      ),
    );
  }
}