import 'dart:async';
import 'dart:ui';

import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:kiwi/kiwi.dart';
import 'package:logging/logging.dart';
import 'package:nc_photos/account.dart';
import 'package:nc_photos/app_localizations.dart';
import 'package:nc_photos/bloc/ls_trashbin.dart';
import 'package:nc_photos/compute_queue.dart';
import 'package:nc_photos/debug_util.dart';
import 'package:nc_photos/di_container.dart';
import 'package:nc_photos/entity/file.dart';
import 'package:nc_photos/entity/file_descriptor.dart';
import 'package:nc_photos/exception_util.dart' as exception_util;
import 'package:nc_photos/k.dart' as k;
import 'package:nc_photos/language_util.dart' as language_util;
import 'package:nc_photos/object_extension.dart';
import 'package:nc_photos/pref.dart';
import 'package:nc_photos/snack_bar_manager.dart';
import 'package:nc_photos/theme.dart';
import 'package:nc_photos/use_case/inflate_file_descriptor.dart';
import 'package:nc_photos/use_case/restore_trashbin.dart';
import 'package:nc_photos/widget/builder/photo_list_item_builder.dart';
import 'package:nc_photos/widget/empty_list_indicator.dart';
import 'package:nc_photos/widget/handler/remove_selection_handler.dart';
import 'package:nc_photos/widget/photo_list_item.dart';
import 'package:nc_photos/widget/photo_list_util.dart' as photo_list_util;
import 'package:nc_photos/widget/selectable_item_stream_list_mixin.dart';
import 'package:nc_photos/widget/selection_app_bar.dart';
import 'package:nc_photos/widget/trashbin_viewer.dart';
import 'package:nc_photos/widget/zoom_menu_button.dart';

class TrashbinBrowserArguments {
  TrashbinBrowserArguments(this.account);

  final Account account;
}

class TrashbinBrowser extends StatefulWidget {
  static const routeName = "/trashbin-browser";

  static Route buildRoute(TrashbinBrowserArguments args) => MaterialPageRoute(
        builder: (context) => TrashbinBrowser.fromArgs(args),
      );

  const TrashbinBrowser({
    Key? key,
    required this.account,
  }) : super(key: key);

  TrashbinBrowser.fromArgs(TrashbinBrowserArguments args, {Key? key})
      : this(
          key: key,
          account: args.account,
        );

  @override
  createState() => _TrashbinBrowserState();

  final Account account;
}

class _TrashbinBrowserState extends State<TrashbinBrowser>
    with SelectableItemStreamListMixin<TrashbinBrowser> {
  @override
  initState() {
    super.initState();
    _initBloc();
    _thumbZoomLevel = Pref().getAlbumBrowserZoomLevelOr(0);
  }

  @override
  build(BuildContext context) {
    return AppTheme(
      child: Scaffold(
        body: BlocListener<LsTrashbinBloc, LsTrashbinBlocState>(
          bloc: _bloc,
          listener: (context, state) => _onStateChange(context, state),
          child: BlocBuilder<LsTrashbinBloc, LsTrashbinBlocState>(
            bloc: _bloc,
            builder: (context, state) => _buildContent(context, state),
          ),
        ),
      ),
    );
  }

  @override
  onItemTap(SelectableItem item, int index) {
    item.as<PhotoListFileItem>()?.run((fileItem) {
      Navigator.pushNamed(
        context,
        TrashbinViewer.routeName,
        arguments: TrashbinViewerArguments(
            widget.account, _backingFiles, fileItem.fileIndex),
      );
    });
  }

  void _initBloc() {
    _bloc = LsTrashbinBloc.of(widget.account);
    if (_bloc.state is LsTrashbinBlocInit) {
      _log.info("[_initBloc] Initialize bloc");
      _reqQuery();
    } else {
      // process the current state
      WidgetsBinding.instance.addPostFrameCallback((_) {
        setState(() {
          _onStateChange(context, _bloc.state);
        });
        _reqQuery();
      });
    }
  }

  Widget _buildContent(BuildContext context, LsTrashbinBlocState state) {
    if (state is LsTrashbinBlocSuccess &&
        !_buildItemQueue.isProcessing &&
        itemStreamListItems.isEmpty) {
      return Column(
        children: [
          AppBar(
            title: Text(L10n.global().albumTrashLabel),
            elevation: 0,
          ),
          Expanded(
            child: EmptyListIndicator(
              icon: Icons.delete_outline,
              text: L10n.global().listEmptyText,
            ),
          ),
        ],
      );
    } else {
      return Stack(
        children: [
          buildItemStreamListOuter(
            context,
            child: Theme(
              data: Theme.of(context).copyWith(
                colorScheme: Theme.of(context).colorScheme.copyWith(
                      secondary: AppTheme.getOverscrollIndicatorColor(context),
                    ),
              ),
              child: CustomScrollView(
                slivers: [
                  _buildAppBar(context),
                  buildItemStreamList(
                    maxCrossAxisExtent: _thumbSize.toDouble(),
                  ),
                ],
              ),
            ),
          ),
          if (state is LsTrashbinBlocLoading || _buildItemQueue.isProcessing)
            const Align(
              alignment: Alignment.bottomCenter,
              child: LinearProgressIndicator(),
            ),
        ],
      );
    }
  }

  Widget _buildAppBar(BuildContext context) {
    if (isSelectionMode) {
      return _buildSelectionAppBar(context);
    } else {
      return _buildNormalAppBar(context);
    }
  }

  Widget _buildSelectionAppBar(BuildContext context) {
    return SelectionAppBar(
      count: selectedListItems.length,
      onClosePressed: () {
        setState(() {
          clearSelectedItems();
        });
      },
      actions: [
        IconButton(
          icon: const Icon(Icons.restore_outlined),
          tooltip: L10n.global().restoreTooltip,
          onPressed: () {
            _onSelectionAppBarRestorePressed();
          },
        ),
        PopupMenuButton<_SelectionAppBarMenuOption>(
          tooltip: MaterialLocalizations.of(context).moreButtonTooltip,
          itemBuilder: (context) => [
            PopupMenuItem(
              value: _SelectionAppBarMenuOption.delete,
              child: Text(L10n.global().deletePermanentlyTooltip),
            ),
          ],
          onSelected: (option) {
            switch (option) {
              case _SelectionAppBarMenuOption.delete:
                _onSelectionAppBarDeletePressed(context);
                break;

              default:
                _log.shout("[_buildSelectionAppBar] Unknown option: $option");
                break;
            }
          },
        )
      ],
    );
  }

  Widget _buildNormalAppBar(BuildContext context) {
    return SliverAppBar(
      title: Text(L10n.global().albumTrashLabel),
      floating: true,
      actions: [
        ZoomMenuButton(
          initialZoom: _thumbZoomLevel,
          minZoom: 0,
          maxZoom: 2,
          onZoomChanged: (value) {
            setState(() {
              _thumbZoomLevel = value.round();
            });
            Pref().setAlbumBrowserZoomLevel(_thumbZoomLevel);
          },
        ),
        PopupMenuButton<_AppBarMenuOption>(
          tooltip: MaterialLocalizations.of(context).moreButtonTooltip,
          itemBuilder: (context) => [
            PopupMenuItem(
              value: _AppBarMenuOption.empty,
              child: Text(L10n.global().emptyTrashbinTooltip),
            ),
          ],
          onSelected: (option) {
            switch (option) {
              case _AppBarMenuOption.empty:
                _onEmptyTrashPressed(context);
                break;

              default:
                _log.shout("[_buildNormalAppBar] Unknown option: $option");
                break;
            }
          },
        ),
      ],
    );
  }

  void _onStateChange(BuildContext context, LsTrashbinBlocState state) {
    if (state is LsTrashbinBlocInit) {
      itemStreamListItems = [];
    } else if (state is LsTrashbinBlocSuccess ||
        state is LsTrashbinBlocLoading) {
      _transformItems(state.items);
    } else if (state is LsTrashbinBlocFailure) {
      _transformItems(state.items);
      SnackBarManager().showSnackBar(SnackBar(
        content: Text(exception_util.toUserString(state.exception)),
        duration: k.snackBarDurationNormal,
      ));
    } else if (state is LsTrashbinBlocInconsistent) {
      _reqQuery();
    }
  }

  Future<void> _onEmptyTrashPressed(BuildContext context) async {
    unawaited(
      showDialog(
        context: context,
        builder: (_) => AlertDialog(
          title: Text(L10n.global().emptyTrashbinConfirmationDialogTitle),
          content: Text(L10n.global().emptyTrashbinConfirmationDialogContent),
          actions: [
            TextButton(
              onPressed: () {
                Navigator.of(context).pop();
                _deleteFiles(_backingFiles);
              },
              child: Text(L10n.global().confirmButtonLabel),
            ),
          ],
        ),
      ),
    );
  }

  Future<void> _onSelectionAppBarRestorePressed() async {
    SnackBarManager().showSnackBar(SnackBar(
      content: Text(L10n.global()
          .restoreSelectedProcessingNotification(selectedListItems.length)),
      duration: k.snackBarDurationShort,
    ));
    final selection = selectedListItems
        .whereType<PhotoListFileItem>()
        .map((e) => e.file)
        .toList();
    setState(() {
      clearSelectedItems();
    });
    final c = KiwiContainer().resolve<DiContainer>();
    final selectedFiles =
        await InflateFileDescriptor(c)(widget.account, selection);
    final failures = <File>[];
    for (final f in selectedFiles) {
      try {
        await RestoreTrashbin(c)(widget.account, f);
      } catch (e, stacktrace) {
        _log.shout(
            "[_onSelectionAppBarRestorePressed] Failed while restoring file: ${logFilename(f.path)}",
            e,
            stacktrace);
        failures.add(f);
      }
    }
    if (failures.isEmpty) {
      SnackBarManager().showSnackBar(SnackBar(
        content: Text(L10n.global().restoreSelectedSuccessNotification),
        duration: k.snackBarDurationNormal,
      ));
    } else {
      SnackBarManager().showSnackBar(SnackBar(
        content: Text(
            L10n.global().restoreSelectedFailureNotification(failures.length)),
        duration: k.snackBarDurationNormal,
      ));
    }
  }

  Future<void> _onSelectionAppBarDeletePressed(BuildContext context) async {
    unawaited(
      showDialog(
        context: context,
        builder: (_) => AlertDialog(
          title: Text(L10n.global().deletePermanentlyConfirmationDialogTitle),
          content:
              Text(L10n.global().deletePermanentlyConfirmationDialogContent),
          actions: [
            TextButton(
              onPressed: () {
                Navigator.of(context).pop();
                _deleteSelected();
              },
              child: Text(L10n.global().confirmButtonLabel),
            ),
          ],
        ),
      ),
    );
  }

  void _transformItems(List<File> files) {
    _buildItemQueue.addJob(
      PhotoListItemBuilderArguments(
        widget.account,
        files,
        sorter: _fileSorter,
        locale: language_util.getSelectedLocale() ??
            PlatformDispatcher.instance.locale,
      ),
      buildPhotoListItem,
      (result) {
        if (mounted) {
          setState(() {
            _backingFiles = result.backingFiles.cast();
            itemStreamListItems = result.listItems;
          });
        }
      },
    );
  }

  Future<void> _deleteSelected() async {
    final selectedFiles = selectedListItems
        .whereType<PhotoListFileItem>()
        .map((e) => e.file)
        .toList();
    setState(() {
      clearSelectedItems();
    });
    return _deleteFiles(selectedFiles);
  }

  Future<void> _deleteFiles(List<FileDescriptor> files) async {
    final c = KiwiContainer().resolve<DiContainer>();
    await RemoveSelectionHandler(c)(
      account: widget.account,
      selection: files,
      shouldCleanupAlbum: false,
    );
  }

  void _reqQuery() {
    _bloc.add(LsTrashbinBlocQuery(widget.account));
  }

  late LsTrashbinBloc _bloc;

  var _backingFiles = <File>[];

  final _buildItemQueue =
      ComputeQueue<PhotoListItemBuilderArguments, PhotoListItemBuilderResult>();

  var _thumbZoomLevel = 0;
  int get _thumbSize => photo_list_util.getThumbSize(_thumbZoomLevel);

  static final _log = Logger("widget.trashbin_browser._TrashbinBrowserState");
}

enum _AppBarMenuOption {
  empty,
}

enum _SelectionAppBarMenuOption {
  delete,
}

int _fileSorter(FileDescriptor fdA, FileDescriptor fdB) {
  final a = fdA as File;
  final b = fdB as File;
  if (a.trashbinDeletionTime == null && b.trashbinDeletionTime == null) {
    // ?
    return 0;
  } else if (a.trashbinDeletionTime == null) {
    return -1;
  } else if (b.trashbinDeletionTime == null) {
    return 1;
  } else {
    return b.trashbinDeletionTime!.compareTo(a.trashbinDeletionTime!);
  }
}