import 'dart:async';

import 'package:flutter/material.dart';
import 'package:flutter/widgets.dart';
import 'package:fluttertoast/fluttertoast.dart';
import 'package:logging/logging.dart';
import 'package:photos/core/configuration.dart';
import 'package:photos/core/event_bus.dart';
import 'package:photos/db/files_db.dart';
import 'package:photos/events/backup_folders_updated_event.dart';
import 'package:photos/events/collection_updated_event.dart';
import 'package:photos/events/local_photos_updated_event.dart';
import 'package:photos/events/tab_changed_event.dart';
import 'package:photos/events/user_logged_out_event.dart';
import 'package:photos/models/collection_items.dart';
import 'package:photos/models/device_folder.dart';
import 'package:photos/services/collections_service.dart';
import 'package:photos/ui/collection_page.dart';
import 'package:photos/ui/common_elements.dart';
import 'package:photos/ui/device_folder_page.dart';
import 'package:photos/ui/loading_widget.dart';
import 'package:photos/ui/thumbnail_widget.dart';
import 'package:photos/utils/navigation_util.dart';
import 'package:photos/utils/toast_util.dart';

class CollectionsGalleryWidget extends StatefulWidget {
  const CollectionsGalleryWidget({Key key}) : super(key: key);

  @override
  _CollectionsGalleryWidgetState createState() =>
      _CollectionsGalleryWidgetState();
}

class _CollectionsGalleryWidgetState extends State<CollectionsGalleryWidget>
    with AutomaticKeepAliveClientMixin {
  final _logger = Logger("CollectionsGallery");
  StreamSubscription<LocalPhotosUpdatedEvent> _localFilesSubscription;
  StreamSubscription<CollectionUpdatedEvent> _collectionUpdatesSubscription;
  StreamSubscription<BackupFoldersUpdatedEvent> _backupFoldersUpdatedEvent;
  StreamSubscription<UserLoggedOutEvent> _loggedOutEvent;

  @override
  void initState() {
    _localFilesSubscription =
        Bus.instance.on<LocalPhotosUpdatedEvent>().listen((event) {
      _logger.info("Files updated");
      setState(() {});
    });
    _collectionUpdatesSubscription =
        Bus.instance.on<CollectionUpdatedEvent>().listen((event) {
      setState(() {});
    });
    _loggedOutEvent = Bus.instance.on<UserLoggedOutEvent>().listen((event) {
      setState(() {});
    });
    _backupFoldersUpdatedEvent =
        Bus.instance.on<BackupFoldersUpdatedEvent>().listen((event) {
      setState(() {});
    });
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    super.build(context);
    _logger.info("Building ");
    return FutureBuilder<CollectionItems>(
      future: _getCollections(),
      builder: (context, snapshot) {
        if (snapshot.hasData) {
          return _getCollectionsGalleryWidget(snapshot.data);
        } else if (snapshot.hasError) {
          return Text(snapshot.error.toString());
        } else {
          return loadWidget;
        }
      },
    );
  }

  Future<CollectionItems> _getCollections() async {
    final filesDB = FilesDB.instance;
    final collectionsService = CollectionsService.instance;
    final userID = Configuration.instance.getUserID();
    final List<DeviceFolder> folders = [];
    final latestLocalFiles = await filesDB.getLatestLocalFiles();
    for (final file in latestLocalFiles) {
      folders.add(DeviceFolder(file.deviceFolder, file.deviceFolder, file));
    }
    folders.sort((first, second) =>
        second.thumbnail.creationTime.compareTo(first.thumbnail.creationTime));

    final List<CollectionWithThumbnail> collectionsWithThumbnail = [];
    final latestCollectionFiles =
        await collectionsService.getLatestCollectionFiles();
    for (final file in latestCollectionFiles) {
      final c = collectionsService.getCollectionByID(file.collectionID);
      if (c.owner.id == userID) {
        collectionsWithThumbnail.add(CollectionWithThumbnail(c, file));
      }
    }
    collectionsWithThumbnail.sort((first, second) {
      return second.thumbnail.updationTime
          .compareTo(first.thumbnail.updationTime);
    });
    return CollectionItems(folders, collectionsWithThumbnail);
  }

  Widget _getCollectionsGalleryWidget(CollectionItems items) {
    return SingleChildScrollView(
      child: Container(
        margin: const EdgeInsets.only(bottom: 50),
        child: Column(
          children: [
            Padding(padding: EdgeInsets.all(6)),
            SectionTitle("on device"),
            Padding(padding: EdgeInsets.all(8)),
            items.folders.isEmpty
                ? Padding(
                    padding: const EdgeInsets.all(22),
                    child: nothingToSeeHere,
                  )
                : Container(
                    height: 170,
                    child: Align(
                      alignment: Alignment.centerLeft,
                      child: items.folders.isEmpty
                          ? nothingToSeeHere
                          : ListView.builder(
                              shrinkWrap: true,
                              scrollDirection: Axis.horizontal,
                              padding: EdgeInsets.fromLTRB(12, 0, 12, 0),
                              physics:
                                  ScrollPhysics(), // to disable GridView's scrolling
                              itemBuilder: (context, index) {
                                return DeviceFolderIcon(items.folders[index]);
                              },
                              itemCount: items.folders.length,
                            ),
                    ),
                  ),
            Padding(padding: EdgeInsets.all(10)),
            Divider(),
            Padding(padding: EdgeInsets.all(10)),
            SectionTitle("on ente"),
            Padding(padding: EdgeInsets.all(12)),
            Configuration.instance.hasConfiguredAccount()
                ? GridView.builder(
                    shrinkWrap: true,
                    padding: EdgeInsets.fromLTRB(0, 0, 12, 0),
                    physics: ScrollPhysics(), // to disable GridView's scrolling
                    itemBuilder: (context, index) {
                      return _buildCollection(
                          context, items.collections, index);
                    },
                    itemCount:
                        items.collections.length + 1, // To include the + button
                    gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
                      crossAxisCount: 2,
                      mainAxisSpacing: 12,
                    ),
                  )
                : nothingToSeeHere,
          ],
        ),
      ),
    );
  }

  Widget _buildCollection(BuildContext context,
      List<CollectionWithThumbnail> collections, int index) {
    if (index < collections.length) {
      final c = collections[index];
      return CollectionItem(c);
    } else {
      return Container(
        padding: EdgeInsets.fromLTRB(28, 0, 28, 58),
        child: OutlinedButton(
          style: OutlinedButton.styleFrom(
            shape: RoundedRectangleBorder(
              borderRadius: BorderRadius.circular(18.0),
            ),
            side: BorderSide(
              width: 1,
              color: Theme.of(context).buttonColor.withOpacity(0.4),
            ),
          ),
          child: Icon(
            Icons.add,
            color: Theme.of(context).buttonColor.withOpacity(0.7),
          ),
          onPressed: () async {
            await showToast(
                "long press to select photos and click + to create an album",
                toastLength: Toast.LENGTH_LONG);
            Bus.instance.fire(
                TabChangedEvent(0, TabChangedEventSource.collections_page));
          },
        ),
      );
    }
  }

  @override
  void dispose() {
    _localFilesSubscription.cancel();
    _collectionUpdatesSubscription.cancel();
    _loggedOutEvent.cancel();
    _backupFoldersUpdatedEvent.cancel();
    super.dispose();
  }

  @override
  bool get wantKeepAlive => true;
}

class DeviceFolderIcon extends StatelessWidget {
  const DeviceFolderIcon(
    this.folder, {
    Key key,
  }) : super(key: key);

  static final kUnsyncedIconOverlay = Container(
    decoration: BoxDecoration(
      gradient: LinearGradient(
        begin: Alignment.topCenter,
        end: Alignment.bottomCenter,
        colors: [
          Colors.transparent,
          Colors.black.withOpacity(0.6),
        ],
        stops: [0.7, 1],
      ),
    ),
    child: Align(
      alignment: Alignment.bottomRight,
      child: Padding(
        padding: const EdgeInsets.only(right: 8, bottom: 8),
        child: Icon(
          Icons.cloud_off_outlined,
          size: 18,
          color: Colors.white.withOpacity(0.9),
        ),
      ),
    ),
  );

  final DeviceFolder folder;

  @override
  Widget build(BuildContext context) {
    final isBackedUp =
        Configuration.instance.getPathsToBackUp().contains(folder.path);
    return GestureDetector(
      child: Container(
        height: 140,
        width: 142,
        padding: const EdgeInsets.all(8.0),
        child: Column(
          children: <Widget>[
            ClipRRect(
              borderRadius: BorderRadius.circular(18.0),
              child: Container(
                child: Hero(
                  tag: "device_folder:" + folder.path + folder.thumbnail.tag(),
                  child: Stack(
                    children: [
                      ThumbnailWidget(
                        folder.thumbnail,
                        shouldShowSyncStatus: false,
                        key: Key("device_folder:" +
                            folder.path +
                            folder.thumbnail.tag()),
                      ),
                      isBackedUp ? Container() : kUnsyncedIconOverlay,
                    ],
                  ),
                ),
                height: 120,
                width: 120,
              ),
            ),
            Padding(
              padding: const EdgeInsets.only(top: 10),
              child: Text(
                folder.name,
                style: TextStyle(
                  fontSize: 12,
                ),
                overflow: TextOverflow.ellipsis,
              ),
            ),
          ],
        ),
      ),
      onTap: () {
        routeToPage(context, DeviceFolderPage(folder));
      },
    );
  }
}

class CollectionItem extends StatelessWidget {
  CollectionItem(
    this.c, {
    Key key,
  }) : super(key: Key(c.collection.id.toString()));

  final CollectionWithThumbnail c;

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      child: Column(
        children: <Widget>[
          ClipRRect(
            borderRadius: BorderRadius.circular(18.0),
            child: Container(
              child: Hero(
                  tag: "collection" + c.thumbnail.tag(),
                  child: ThumbnailWidget(
                    c.thumbnail,
                    key: Key("collection" + c.thumbnail.tag()),
                  )),
              height: 140,
              width: 140,
            ),
          ),
          Padding(padding: EdgeInsets.all(4)),
          Expanded(
            child: Text(
              c.collection.name,
              style: TextStyle(
                fontSize: 16,
              ),
              overflow: TextOverflow.ellipsis,
            ),
          ),
        ],
      ),
      onTap: () {
        routeToPage(context, CollectionPage(c));
      },
    );
  }
}

class SectionTitle extends StatelessWidget {
  final String title;
  final Alignment alignment;
  final double opacity;

  const SectionTitle(
    this.title, {
    this.opacity: 0.8,
    Key key,
    this.alignment = Alignment.centerLeft,
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Container(
        margin: EdgeInsets.fromLTRB(24, 12, 0, 0),
        child: Column(children: [
          Align(
            alignment: alignment,
            child: Text(
              title,
              style: TextStyle(
                fontWeight: FontWeight.bold,
                color: Theme.of(context).buttonColor.withOpacity(this.opacity),
                fontSize: 20,
                letterSpacing: 1,
              ),
            ),
          ),
        ]));
  }
}