import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:flutter/widgets.dart';
import 'package:flutter_gen/gen_l10n/app_localizations.dart';
import 'package:logging/logging.dart';
import 'package:nc_photos/account.dart';
import 'package:nc_photos/api/api_util.dart' as api_util;
import 'package:nc_photos/entity/album.dart';
import 'package:nc_photos/entity/album/cover_provider.dart';
import 'package:nc_photos/entity/album/provider.dart';
import 'package:nc_photos/entity/file.dart';
import 'package:nc_photos/entity/file/data_source.dart';
import 'package:nc_photos/entity/file_util.dart' as file_util;
import 'package:nc_photos/iterable_extension.dart';
import 'package:nc_photos/k.dart' as k;
import 'package:nc_photos/list_extension.dart';
import 'package:nc_photos/snack_bar_manager.dart';
import 'package:nc_photos/theme.dart';
import 'package:nc_photos/use_case/populate_album.dart';
import 'package:nc_photos/use_case/remove.dart';
import 'package:nc_photos/use_case/update_album.dart';
import 'package:nc_photos/widget/album_viewer_mixin.dart';
import 'package:nc_photos/widget/photo_list_item.dart';
import 'package:nc_photos/widget/selectable_item_stream_list_mixin.dart';
import 'package:nc_photos/widget/viewer.dart';

class DynamicAlbumViewerArguments {
  DynamicAlbumViewerArguments(this.account, this.album);

  final Account account;
  final Album album;
}

class DynamicAlbumViewer extends StatefulWidget {
  static const routeName = "/dynamic-album-viewer";

  DynamicAlbumViewer({
    Key key,
    @required this.account,
    @required this.album,
  }) : super(key: key);

  DynamicAlbumViewer.fromArgs(DynamicAlbumViewerArguments args, {Key key})
      : this(
          key: key,
          account: args.account,
          album: args.album,
        );

  @override
  createState() => _DynamicAlbumViewerState();

  final Account account;
  final Album album;
}

class _DynamicAlbumViewerState extends State<DynamicAlbumViewer>
    with
        WidgetsBindingObserver,
        SelectableItemStreamListMixin<DynamicAlbumViewer>,
        AlbumViewerMixin<DynamicAlbumViewer> {
  @override
  initState() {
    super.initState();
    _initAlbum();
  }

  @override
  build(BuildContext context) {
    return AppTheme(
      child: Scaffold(
        body: Builder(builder: (context) => _buildContent(context)),
      ),
    );
  }

  void _initAlbum() {
    assert(widget.album.provider is AlbumDynamicProvider);
    PopulateAlbum()(widget.account, widget.album).then((items) {
      if (mounted) {
        setState(() {
          _album = widget.album;
          _transformItems(items);
          final coverFile = initCover(widget.account, _backingFiles);
          _updateAlbumPostPopulate(coverFile, items);
        });
      }
    });
  }

  void _updateAlbumPostPopulate(File coverFile, List<AlbumItem> items) {
    bool shouldUpdate = false;
    if (coverFile != null && _album.coverProvider is AlbumAutoCoverProvider) {
      // cache the result for later use
      if (coverFile.path !=
          (_album.coverProvider as AlbumAutoCoverProvider).coverFile?.path) {
        _log.info("[_updateAlbumPostPopulate] Update album cover");
        _album = _album.copyWith(
            coverProvider: AlbumAutoCoverProvider(coverFile: coverFile));
        shouldUpdate = true;
      }
    }
    DateTime latestItemTime;
    try {
      latestItemTime = items
          .whereType<AlbumFileItem>()
          .map((e) => e.file)
          .where((element) => file_util.isSupportedFormat(element))
          .sorted(compareFileDateTimeDescending)
          .first
          .bestDateTime;
    } catch (_) {
      latestItemTime = null;
    }
    if (latestItemTime != _album.provider.latestItemTime) {
      _log.info(
          "[_updateAlbumPostPopulate] Update album time: $latestItemTime");
      _album = _album.copyWith(
        provider: (_album.provider as AlbumDynamicProvider).copyWith(
          latestItemTime: latestItemTime,
        ),
      );
      shouldUpdate = true;
    }
    if (shouldUpdate) {
      UpdateAlbum(AlbumRepo(AlbumCachedDataSource()))(widget.account, _album);
    }
  }

  Widget _buildContent(BuildContext context) {
    if (_album == null) {
      return CustomScrollView(
        slivers: [
          buildNormalAppBar(context, widget.account, widget.album),
          const SliverToBoxAdapter(
            child: const LinearProgressIndicator(),
          ),
        ],
      );
    }
    return buildItemStreamListOuter(
      context,
      child: Theme(
        data: Theme.of(context).copyWith(
          accentColor: AppTheme.getOverscrollIndicatorColor(context),
        ),
        child: CustomScrollView(
          slivers: [
            _buildAppBar(context),
            SliverPadding(
              padding: const EdgeInsets.all(16),
              sliver: buildItemStreamList(context),
            ),
          ],
        ),
      ),
    );
  }

  Widget _buildAppBar(BuildContext context) {
    if (isSelectionMode) {
      return buildSelectionAppBar(context, [
        PopupMenuButton(
          tooltip: MaterialLocalizations.of(context).moreButtonTooltip,
          itemBuilder: (context) => [
            PopupMenuItem(
              value: _SelectionAppBarOption.delete,
              child: Text(AppLocalizations.of(context).deleteSelectedTooltip),
            ),
          ],
          onSelected: (option) {
            if (option == _SelectionAppBarOption.delete) {
              _onSelectionAppBarDeletePressed();
            }
          },
        ),
      ]);
    } else {
      return buildNormalAppBar(context, widget.account, _album);
    }
  }

  void _onItemTap(int index) {
    Navigator.pushNamed(context, Viewer.routeName,
        arguments: ViewerArguments(widget.account, _backingFiles, index));
  }

  void _onSelectionAppBarDeletePressed() async {
    SnackBarManager().showSnackBar(SnackBar(
      content: Text(AppLocalizations.of(context)
          .deleteSelectedProcessingNotification(selectedListItems.length)),
      duration: k.snackBarDurationShort,
    ));

    final selectedIndexes =
        selectedListItems.map((e) => itemStreamListItems.indexOf(e)).toList();
    final selectedFiles = _backingFiles.takeIndex(selectedIndexes).toList();
    setState(() {
      clearSelectedItems();
    });

    final fileRepo = FileRepo(FileCachedDataSource());
    final albumRepo = AlbumRepo(AlbumCachedDataSource());
    final failures = <File>[];
    for (final f in selectedFiles) {
      try {
        await Remove(fileRepo, albumRepo).call(widget.account, f);
      } catch (e, stacktrace) {
        _log.shout(
            "[_onSelectionAppBarDeletePressed] Failed while removing file" +
                (kDebugMode ? ": ${f.path}" : ""),
            e,
            stacktrace);
        failures.add(f);
      }
    }

    if (failures.isEmpty) {
      SnackBarManager().showSnackBar(SnackBar(
        content: Text(
            AppLocalizations.of(context).deleteSelectedSuccessNotification),
        duration: k.snackBarDurationNormal,
      ));
    } else {
      SnackBarManager().showSnackBar(SnackBar(
        content: Text(AppLocalizations.of(context)
            .deleteSelectedFailureNotification(failures.length)),
        duration: k.snackBarDurationNormal,
      ));
    }
    final successes =
        selectedFiles.where((element) => !failures.containsIdentical(element));
    if (successes.isNotEmpty) {
      setState(() {
        _backingFiles
            .removeWhere((element) => successes.containsIdentical(element));
        _onBackingFilesUpdated();
      });
    }
  }

  void _transformItems(List<AlbumItem> items) {
    _backingFiles = items
        .whereType<AlbumFileItem>()
        .map((e) => e.file)
        .where((element) => file_util.isSupportedFormat(element))
        .sorted(compareFileDateTimeDescending);
    _onBackingFilesUpdated();
  }

  void _onBackingFilesUpdated() {
    itemStreamListItems = () sync* {
      for (int i = 0; i < _backingFiles.length; ++i) {
        final f = _backingFiles[i];

        final previewUrl = api_util.getFilePreviewUrl(widget.account, f,
            width: thumbSize, height: thumbSize);
        if (file_util.isSupportedImageFormat(f)) {
          yield _ImageListItem(
            file: f,
            account: widget.account,
            previewUrl: previewUrl,
            onTap: () => _onItemTap(i),
          );
        } else if (file_util.isSupportedVideoFormat(f)) {
          yield _VideoListItem(
            account: widget.account,
            previewUrl: previewUrl,
            onTap: () => _onItemTap(i),
          );
        } else {
          _log.shout(
              "[_onBackingFilesUpdated] Unsupported file format: ${f.contentType}");
        }
      }
    }();
  }

  Album _album;
  var _backingFiles = <File>[];

  static final _log =
      Logger("widget.dynamic_album_viewer._DynamicAlbumViewerState");
}

class _ImageListItem extends SelectableItemStreamListItem {
  _ImageListItem({
    @required this.file,
    @required this.account,
    @required this.previewUrl,
    VoidCallback onTap,
  }) : super(onTap: onTap, isSelectable: true);

  @override
  buildWidget(BuildContext context) {
    return PhotoListImage(
      account: account,
      previewUrl: previewUrl,
      isGif: file.contentType == "image/gif",
    );
  }

  final File file;
  final Account account;
  final String previewUrl;
}

class _VideoListItem extends SelectableItemStreamListItem {
  _VideoListItem({
    @required this.account,
    @required this.previewUrl,
    VoidCallback onTap,
  }) : super(onTap: onTap, isSelectable: true);

  @override
  buildWidget(BuildContext context) {
    return PhotoListVideo(
      account: account,
      previewUrl: previewUrl,
    );
  }

  final Account account;
  final String previewUrl;
}

enum _SelectionAppBarOption {
  delete,
}