import 'dart:async';

import 'package:aves/model/actions/entry_info_actions.dart';
import 'package:aves/model/actions/events.dart';
import 'package:aves/model/entry.dart';
import 'package:aves/model/filters/filters.dart';
import 'package:aves/model/source/collection_lens.dart';
import 'package:aves/theme/durations.dart';
import 'package:aves/widgets/common/basic/insets.dart';
import 'package:aves/widgets/common/providers/media_query_data_provider.dart';
import 'package:aves/widgets/filter_grids/common/action_delegates/chip.dart';
import 'package:aves/widgets/viewer/action/entry_info_action_delegate.dart';
import 'package:aves/widgets/viewer/embedded/embedded_data_opener.dart';
import 'package:aves/widgets/viewer/info/basic_section.dart';
import 'package:aves/widgets/viewer/info/info_app_bar.dart';
import 'package:aves/widgets/viewer/info/location_section.dart';
import 'package:aves/widgets/viewer/info/metadata/metadata_section.dart';
import 'package:aves/widgets/viewer/multipage/conductor.dart';
import 'package:aves/widgets/viewer/notifications.dart';
import 'package:aves/widgets/viewer/page_entry_builder.dart';
import 'package:flutter/material.dart';
import 'package:provider/provider.dart';

class InfoPage extends StatefulWidget {
  final CollectionLens? collection;
  final ValueNotifier<AvesEntry?> entryNotifier;
  final ValueNotifier<bool> isScrollingNotifier;

  const InfoPage({
    super.key,
    required this.collection,
    required this.entryNotifier,
    required this.isScrollingNotifier,
  });

  @override
  State<StatefulWidget> createState() => _InfoPageState();
}

class _InfoPageState extends State<InfoPage> {
  final ScrollController _scrollController = ScrollController();
  bool _scrollStartFromTop = false;

  static const splitScreenWidthThreshold = 600;

  @override
  Widget build(BuildContext context) {
    return MediaQueryDataProvider(
      child: Scaffold(
        body: GestureAreaProtectorStack(
          child: SafeArea(
            bottom: false,
            child: NotificationListener<ScrollNotification>(
              onNotification: _handleTopScroll,
              child: Selector<MediaQueryData, double>(
                selector: (context, mq) => mq.size.width,
                builder: (context, mqWidth, child) {
                  return ValueListenableBuilder<AvesEntry?>(
                    valueListenable: widget.entryNotifier,
                    builder: (context, mainEntry, child) {
                      if (mainEntry == null) return const SizedBox();

                      Widget _buildContent({AvesEntry? pageEntry}) {
                        final targetEntry = pageEntry ?? mainEntry;
                        return EmbeddedDataOpener(
                          entry: targetEntry,
                          child: _InfoPageContent(
                            collection: widget.collection,
                            entry: targetEntry,
                            isScrollingNotifier: widget.isScrollingNotifier,
                            scrollController: _scrollController,
                            split: mqWidth > splitScreenWidthThreshold,
                            goToViewer: _goToViewer,
                          ),
                        );
                      }

                      return mainEntry.isBurst
                          ? PageEntryBuilder(
                              multiPageController: context.read<MultiPageConductor>().getController(mainEntry),
                              builder: (pageEntry) => _buildContent(pageEntry: pageEntry),
                            )
                          : _buildContent();
                    },
                  );
                },
              ),
            ),
          ),
        ),
        resizeToAvoidBottomInset: false,
      ),
    );
  }

  bool _handleTopScroll(ScrollNotification notification) {
    if (notification is ScrollStartNotification) {
      final metrics = notification.metrics;
      _scrollStartFromTop = metrics.pixels == metrics.minScrollExtent;
    }
    if (_scrollStartFromTop) {
      if (notification is ScrollUpdateNotification) {
        _scrollStartFromTop = notification.scrollDelta! < 0;
      } else if (notification is ScrollEndNotification) {
        _scrollStartFromTop = false;
      } else if (notification is OverscrollNotification) {
        if (notification.overscroll < 0) {
          _goToViewer();
          _scrollStartFromTop = false;
        }
      }
    }
    return false;
  }

  void _goToViewer() {
    final animationDuration = context.read<DurationsData>().viewerVerticalPageScrollAnimation;
    ShowImageNotification().dispatch(context);
    _scrollController.animateTo(
      0,
      duration: animationDuration,
      curve: Curves.easeInOut,
    );
  }
}

class _InfoPageContent extends StatefulWidget {
  final CollectionLens? collection;
  final AvesEntry entry;
  final ValueNotifier<bool> isScrollingNotifier;
  final ScrollController scrollController;
  final bool split;
  final VoidCallback goToViewer;

  const _InfoPageContent({
    required this.collection,
    required this.entry,
    required this.isScrollingNotifier,
    required this.scrollController,
    required this.split,
    required this.goToViewer,
  });

  @override
  State<_InfoPageContent> createState() => _InfoPageContentState();
}

class _InfoPageContentState extends State<_InfoPageContent> {
  final List<StreamSubscription> _subscriptions = [];
  late EntryInfoActionDelegate _actionDelegate;
  final ValueNotifier<Map<String, MetadataDirectory>> _metadataNotifier = ValueNotifier({});
  final ValueNotifier<EntryInfoAction?> _isEditingMetadataNotifier = ValueNotifier(null);

  static const horizontalPadding = EdgeInsets.symmetric(horizontal: 8);

  CollectionLens? get collection => widget.collection;

  AvesEntry get entry => widget.entry;

  @override
  void initState() {
    super.initState();
    _registerWidget(widget);
  }

  @override
  void didUpdateWidget(covariant _InfoPageContent oldWidget) {
    super.didUpdateWidget(oldWidget);

    if (oldWidget.entry != widget.entry) {
      _unregisterWidget(oldWidget);
      _registerWidget(widget);
    }
  }

  @override
  void dispose() {
    _unregisterWidget(widget);
    super.dispose();
  }

  void _registerWidget(_InfoPageContent widget) {
    _actionDelegate = EntryInfoActionDelegate(widget.entry, collection);
    _subscriptions.add(_actionDelegate.eventStream.listen(_onActionDelegateEvent));
  }

  void _unregisterWidget(_InfoPageContent widget) {
    _subscriptions
      ..forEach((sub) => sub.cancel())
      ..clear();
  }

  @override
  Widget build(BuildContext context) {
    final basicSection = BasicSection(
      entry: entry,
      collection: collection,
      actionDelegate: _actionDelegate,
      isEditingMetadataNotifier: _isEditingMetadataNotifier,
      onFilter: _onFilter,
    );
    final locationAtTop = widget.split && entry.hasGps;
    final locationSection = LocationSection(
      collection: collection,
      entry: entry,
      showTitle: !locationAtTop,
      isScrollingNotifier: widget.isScrollingNotifier,
      onFilter: _onFilter,
    );
    final basicAndLocationSliver = locationAtTop
        ? SliverToBoxAdapter(
            child: Row(
              crossAxisAlignment: CrossAxisAlignment.start,
              children: [
                Expanded(child: basicSection),
                const SizedBox(width: 8),
                Expanded(child: locationSection),
              ],
            ),
          )
        : SliverList(
            delegate: SliverChildListDelegate.fixed(
              [
                basicSection,
                locationSection,
              ],
            ),
          );
    final metadataSliver = MetadataSectionSliver(
      entry: entry,
      metadataNotifier: _metadataNotifier,
    );

    return NotificationListener<ReverseFilterNotification>(
      onNotification: (notification) {
        _onFilter(notification.reversedFilter);
        return true;
      },
      child: CustomScrollView(
        controller: widget.scrollController,
        slivers: [
          InfoAppBar(
            entry: entry,
            actionDelegate: _actionDelegate,
            metadataNotifier: _metadataNotifier,
            onBackPressed: widget.goToViewer,
          ),
          SliverPadding(
            padding: horizontalPadding + const EdgeInsets.only(top: 8),
            sliver: basicAndLocationSliver,
          ),
          SliverPadding(
            padding: horizontalPadding + const EdgeInsets.only(bottom: 8),
            sliver: metadataSliver,
          ),
          const BottomPaddingSliver(),
        ],
      ),
    );
  }

  void _onActionDelegateEvent(ActionEvent<EntryInfoAction> event) {
    Future.delayed(Durations.dialogTransitionAnimation).then((_) {
      if (event is ActionStartedEvent) {
        _isEditingMetadataNotifier.value = event.action;
      } else if (event is ActionEndedEvent) {
        _isEditingMetadataNotifier.value = null;
      }
    });
  }

  void _onFilter(CollectionFilter filter) => FilterSelectedNotification(filter).dispatch(context);
}