import 'dart:async';
import 'package:flutter/material.dart';
import 'package:hive_flutter/adapters.dart';
import 'package:isar_community/isar.dart';
import 'package:mangayomi/main.dart';
import 'package:mangayomi/models/track.dart';
import 'package:mangayomi/models/track_search.dart';
import 'package:mangayomi/modules/tracker_library/tracker_library_card.dart';
import 'package:mangayomi/modules/tracker_library/tracker_library_section.dart';
import 'package:mangayomi/providers/l10n_providers.dart';
import 'package:super_sliver_list/super_sliver_list.dart';

class TrackerSectionScreen extends StatefulWidget {
  final TrackLibrarySection section;

  const TrackerSectionScreen({super.key, required this.section});

  @override
  State<TrackerSectionScreen> createState() => _TrackerSectionScreenState();
}

class _TrackerSectionScreenState extends State<TrackerSectionScreen> {
  String _errorMessage = "";
  bool _isLoading = true;
  List<TrackSearch> _tracks = [];
  late StreamSubscription<List<Track>> _trackStreamSub;
  Map<int, Track> _trackIndex = {};

  @override
  void initState() {
    super.initState();
    _fetchData();
    _subscribeToTracks();
  }

  void _subscribeToTracks() {
    _trackStreamSub = isar.tracks
        .filter()
        .itemTypeEqualTo(widget.section.itemType)
        .mangaIdIsNotNull()
        .watch(fireImmediately: true)
        .listen((tracks) {
          if (mounted) {
            setState(() {
              _trackIndex = {
                for (final t in tracks)
                  if (t.mediaId != null) t.mediaId!: t,
              };
            });
          }
        });
  }

  @override
  void didUpdateWidget(covariant TrackerSectionScreen oldWidget) {
    super.didUpdateWidget(oldWidget);
    if (oldWidget.section.itemType != widget.section.itemType) {
      _trackStreamSub.cancel();
      _subscribeToTracks();
    }
    _fetchData();
  }

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

  @override
  Widget build(BuildContext context) {
    final l10n = l10nLocalizations(context)!;
    return Scaffold(
      body: SizedBox(
        height: 260,
        child: Column(
          children: [
            ListTile(dense: true, title: Text(widget.section.name)),
            Flexible(
              child: _isLoading
                  ? const Center(child: CircularProgressIndicator())
                  : Builder(
                      builder: (context) {
                        if (_errorMessage.isNotEmpty) {
                          return Center(child: Text(_errorMessage));
                        }
                        if (_tracks.isNotEmpty) {
                          return SuperListView.builder(
                            extentPrecalculationPolicy:
                                SuperPrecalculationPolicy(),
                            scrollDirection: Axis.horizontal,
                            itemCount: _tracks.length,
                            itemBuilder: (context, index) {
                              final track = _tracks[index];
                              return TrackerLibraryImageCard(
                                track: track,
                                itemType: widget.section.itemType,
                                libraryTrack: _trackIndex[track.mediaId],
                              );
                            },
                          );
                        }
                        return Center(child: Text(l10n.no_result));
                      },
                    ),
            ),
          ],
        ),
      ),
    );
  }

  Future<void> _fetchData() async {
    final box = await Hive.openBox("tracker_library");
    final key =
        "${widget.section.syncId}-${widget.section.itemType.name}-${widget.section.name}";
    if (_checkCache(box, key)) return;
    try {
      _errorMessage = "";
      _tracks = await widget.section.func() ?? [];
      box.put(key, _tracks);
      if (mounted) {
        setState(() => _isLoading = false);
      }
    } catch (e) {
      if (mounted) {
        setState(() {
          _errorMessage = e.toString();
          _isLoading = false;
        });
      }
    }
  }

  bool _checkCache(Box<dynamic> box, String key) {
    if (!widget.section.isSearch && box.containsKey(key)) {
      final temp = box.get(key);
      if (temp is List<TrackSearch>) {
        _errorMessage = "";
        _tracks = temp;
        if (mounted) setState(() => _isLoading = false);
        return true;
      }
    }
    return false;
  }
}

class SuperPrecalculationPolicy extends ExtentPrecalculationPolicy {
  @override
  bool shouldPrecalculateExtents(ExtentPrecalculationContext context) {
    return context.numberOfItems < 100;
  }
}