import 'dart:async';

import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';

import '../../../api/marianumcloud/webdav/queries/list_files/cacheable_file.dart';
import '../../../api/marianumcloud/webdav/queries/list_files/list_files_response.dart';
import '../../../routing/app_routes.dart';
import '../../../state/app/infrastructure/loadable_state/loadable_state.dart';
import '../../../state/app/infrastructure/loadable_state/view/loadable_state_consumer.dart';
import '../../../state/app/infrastructure/utility_widgets/bloc_module.dart';
import '../../../state/app/modules/files/bloc/files_bloc.dart';
import '../../../state/app/modules/files/bloc/files_state.dart';
import '../../../utils/cache_invalidation_bus.dart';
import '../../../widget/placeholder_view.dart';
import 'data/file_sort.dart';
import 'data/webdav_path.dart';
import 'search/files_search_delegate.dart';
import 'widgets/add_file_menu.dart';
import 'widgets/clipboard_banner.dart';
import 'widgets/file_element.dart';
import 'widgets/files_sort_actions.dart';

class Files extends StatelessWidget {
  final List<String> path;

  Files({List<String>? path, super.key}) : path = path ?? [];

  @override
  Widget build(BuildContext context) =>
      BlocModule<FilesBloc, LoadableState<FilesState>>(
        create: (_) => FilesBloc(initialPath: path),
        child: (context, _, _) => _FilesView(path: path),
      );
}

class _FilesView extends StatefulWidget {
  final List<String> path;
  const _FilesView({required this.path});

  @override
  State<_FilesView> createState() => _FilesViewState();
}

class _FilesViewState extends State<_FilesView> {
  late final StreamSubscription<String> _invalidationSub;

  // The list builder also runs for loading flips and parent rebuilds; only a
  // new listing or a changed sort needs another sort pass.
  Object? _sortedKey;
  List<CacheableFile> _sortedFiles = const [];

  List<CacheableFile> _sorted(ListFilesResponse listing, FileSort sort) {
    final key = (listing, sort);
    if (key == _sortedKey) return _sortedFiles;
    _sortedKey = key;
    return _sortedFiles = listing.sortedBy(sort);
  }

  @override
  void initState() {
    super.initState();
    _invalidationSub = CacheInvalidationBus.listFilesStream.listen(
      _onInvalidation,
    );
  }

  void _onInvalidation(String invalidatedPath) {
    if (!mounted) return;
    if (invalidatedPath != listFilesCacheKey(widget.path)) return;
    context.read<FilesBloc>().refresh();
  }

  @override
  void dispose() {
    _invalidationSub.cancel();
    super.dispose();
  }

  Future<void> _mediaUpload(List<String>? paths) async {
    if (paths == null) return;
    final bloc = context.read<FilesBloc>();
    unawaited(
      AppRoutes.openFilesUpload(
        context,
        filePaths: paths,
        remotePath: widget.path.join('/'),
        onUploadFinished: (_) => bloc.refresh(),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    final bloc = context.read<FilesBloc>();
    // Selected here, not in the LoadableStateConsumer child: that closure runs
    // during the consumer's build, where this context may not subscribe.
    final sort = context.select(fileSortOf);
    return Scaffold(
      appBar: AppBar(
        title: Text(widget.path.isNotEmpty ? widget.path.last : 'Dateien'),
        actions: [
          const FilesSortActions(),
          IconButton(
            tooltip: 'Suchen',
            icon: const Icon(Icons.search),
            onPressed: () async {
              final delegate = FilesSearchDelegate(pathScope: widget.path);
              await showSearch<void>(context: context, delegate: delegate);
              delegate.disposeController();
            },
          ),
        ],
      ),
      floatingActionButton: FloatingActionButton(
        heroTag: 'uploadFile',
        backgroundColor: Theme.of(context).primaryColor,
        onPressed: () =>
            showAddFileSheet(context, bloc: bloc, onPickedFiles: _mediaUpload),
        child: const Icon(Icons.add),
      ),
      body: Column(
        children: [
          ClipboardBanner(
            currentFolder: webdavFolderPath(widget.path),
            onPasteDone: bloc.refresh,
          ),
          Expanded(
            child: LoadableStateConsumer<FilesBloc, FilesState>(
              isReady: (state) => state.listing != null,
              child: (state, _) {
                final listing = state.listing!;
                if (listing.files.isEmpty) {
                  return const PlaceholderView(
                    icon: Icons.folder_off_rounded,
                    text: 'Der Ordner ist leer',
                  );
                }
                final files = _sorted(listing, sort);
                return ListView.builder(
                  padding: EdgeInsets.zero,
                  itemCount: files.length,
                  itemBuilder: (context, index) =>
                      FileElement(files[index], widget.path, bloc.refresh),
                );
              },
            ),
          ),
        ],
      ),
    );
  }
}