import "dart:async";
import 'dart:developer' as dev;

import "package:flutter/material.dart";
import "package:photos/core/constants.dart";
import "package:photos/core/event_bus.dart";
import "package:photos/db/files_db.dart";
import "package:photos/events/files_updated_event.dart";
import "package:photos/events/local_photos_updated_event.dart";
import 'package:photos/models/file/file.dart';
import "package:photos/models/file_load_result.dart";
import "package:photos/models/gallery_type.dart";
import "package:photos/models/search/hierarchical/hierarchical_search_filter.dart";
import "package:photos/models/search/hierarchical/location_filter.dart";
import "package:photos/models/selected_files.dart";
import "package:photos/services/collections_service.dart";
import "package:photos/services/filter/db_filters.dart";
import "package:photos/services/location_service.dart";
import "package:photos/states/location_screen_state.dart";
import "package:photos/theme/ente_theme.dart";
import "package:photos/ui/common/loading_widget.dart";
import "package:photos/ui/viewer/actions/file_selection_overlay_bar.dart";
import "package:photos/ui/viewer/gallery/gallery.dart";
import "package:photos/ui/viewer/gallery/gallery_app_bar_widget.dart";
import "package:photos/ui/viewer/gallery/hierarchical_search_gallery.dart";
import "package:photos/ui/viewer/gallery/state/gallery_files_inherited_widget.dart";
import "package:photos/ui/viewer/gallery/state/inherited_search_filter_data.dart";
import "package:photos/ui/viewer/gallery/state/search_filter_data_provider.dart";
import "package:photos/ui/viewer/gallery/state/selection_state.dart";

class LocationScreen extends StatefulWidget {
  final String tagPrefix;
  const LocationScreen({this.tagPrefix = "", super.key});

  @override
  State<LocationScreen> createState() => _LocationScreenState();
}

class _LocationScreenState extends State<LocationScreen> {
  final selectedFiles = SelectedFiles();

  @override
  Widget build(BuildContext context) {
    final heightOfStatusBar = MediaQuery.of(context).viewPadding.top;
    const heightOfAppBar = 90.0;
    final locationTag =
        InheritedLocationScreenState.of(context).locationTagEntity.item;

    return GalleryFilesState(
      child: InheritedSearchFilterDataWrapper(
        searchFilterDataProvider: SearchFilterDataProvider(
          initialGalleryFilter: LocationFilter(
            locationTag: locationTag,
            occurrence: kMostRelevantFilter,
          ),
        ),
        child: Scaffold(
          appBar: PreferredSize(
            preferredSize: const Size(double.infinity, heightOfAppBar),
            child: GalleryAppBarWidget(
              GalleryType.locationTag,
              locationTag.name,
              selectedFiles,
            ),
          ),
          body: Column(
            children: <Widget>[
              SizedBox(
                height: MediaQuery.of(context).size.height -
                    (heightOfAppBar + heightOfStatusBar),
                width: double.infinity,
                child: LocationGalleryWidget(
                  tagPrefix: widget.tagPrefix,
                  selectedFiles: selectedFiles,
                ),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

class LocationGalleryWidget extends StatefulWidget {
  final String tagPrefix;
  final SelectedFiles selectedFiles;
  const LocationGalleryWidget({
    required this.tagPrefix,
    required this.selectedFiles,
    super.key,
  });

  @override
  State<LocationGalleryWidget> createState() => _LocationGalleryWidgetState();
}

class _LocationGalleryWidgetState extends State<LocationGalleryWidget> {
  late final Future<FileLoadResult> fileLoadResult;
  late final List<EnteFile> allFilesWithLocation;

  final _selectedFiles = SelectedFiles();
  late final StreamSubscription<LocalPhotosUpdatedEvent> _filesUpdateEvent;
  @override
  void initState() {
    super.initState();

    final collectionsToHide =
        CollectionsService.instance.getHiddenCollectionIds();
    fileLoadResult = FilesDB.instance
        .fetchAllUploadedAndSharedFilesWithLocation(
      galleryLoadStartTime,
      galleryLoadEndTime,
      limit: null,
      asc: false,
      filterOptions: DBFilterOptions(
        ignoredCollectionIDs: collectionsToHide,
        hideIgnoredForUpload: true,
      ),
    )
        .then((value) {
      allFilesWithLocation = value.files;
      _filesUpdateEvent =
          Bus.instance.on<LocalPhotosUpdatedEvent>().listen((event) {
        if (event.type == EventType.deletedFromDevice ||
            event.type == EventType.deletedFromEverywhere ||
            event.type == EventType.deletedFromRemote ||
            event.type == EventType.hide) {
          for (var updatedFile in event.updatedFiles) {
            allFilesWithLocation.remove(updatedFile);
          }
          if (mounted) {
            setState(() {});
          }
        }
      });
      return value;
    });
  }

  @override
  void dispose() {
    InheritedLocationScreenState.memoryCountNotifier.value = null;
    _filesUpdateEvent.cancel();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) {
    final selectedRadius =
        InheritedLocationScreenState.of(context).locationTagEntity.item.radius;
    final centerPoint = InheritedLocationScreenState.of(context)
        .locationTagEntity
        .item
        .centerPoint;

    Future<FileLoadResult> filterFiles() async {
      //waiting for allFilesWithLocation to be initialized
      await fileLoadResult;
      final stopWatch = Stopwatch()..start();
      final filesInLocation = allFilesWithLocation;
      filesInLocation.removeWhere((f) {
        return !isFileInsideLocationTag(
          centerPoint,
          f.location!,
          selectedRadius,
        );
      });
      dev.log(
        "Time taken to get all files in a location tag: ${stopWatch.elapsedMilliseconds} ms",
      );
      stopWatch.stop();
      InheritedLocationScreenState.memoryCountNotifier.value =
          filesInLocation.length;

      return Future.value(
        FileLoadResult(
          filesInLocation,
          false,
        ),
      );
    }

    return FutureBuilder(
      //rebuild gallery only when there is change in radius or center point
      key: ValueKey("$centerPoint$selectedRadius"),
      builder: (context, snapshot) {
        if (snapshot.hasData) {
          return SelectionState(
            selectedFiles: _selectedFiles,
            child: Stack(
              alignment: Alignment.bottomCenter,
              children: [
                Builder(
                  builder: (context) {
                    return ValueListenableBuilder(
                      valueListenable: InheritedSearchFilterData.of(context)
                          .searchFilterDataProvider!
                          .isSearchingNotifier,
                      builder: (context, value, _) {
                        return value
                            ? HierarchicalSearchGallery(
                                tagPrefix: widget.tagPrefix,
                                selectedFiles: _selectedFiles,
                              )
                            : Gallery(
                                loadingWidget: Column(
                                  children: [
                                    EnteLoadingWidget(
                                      color: getEnteColorScheme(context)
                                          .strokeMuted,
                                    ),
                                  ],
                                ),
                                asyncLoader: (
                                  creationStartTime,
                                  creationEndTime, {
                                  limit,
                                  asc,
                                }) async {
                                  return snapshot.data as FileLoadResult;
                                },
                                reloadEvent:
                                    Bus.instance.on<LocalPhotosUpdatedEvent>(),
                                removalEventTypes: const {
                                  EventType.deletedFromRemote,
                                  EventType.deletedFromEverywhere,
                                },
                                selectedFiles: _selectedFiles,
                                tagPrefix: widget.tagPrefix,
                              );
                      },
                    );
                  },
                ),
                FileSelectionOverlayBar(
                  GalleryType.locationTag,
                  _selectedFiles,
                ),
              ],
            ),
          );
        } else {
          return const Column(
            children: [
              Expanded(
                child: EnteLoadingWidget(),
              ),
            ],
          );
        }
      },
      future: filterFiles(),
    );
  }
}