relatica/lib/screens/gallery_screen.dart

import 'package:cached_network_image/cached_network_image.dart';
import 'package:flutter/material.dart';
import 'package:logging/logging.dart';
import 'package:provider/provider.dart';

import '../controls/standard_appbar.dart';
import '../globals.dart';
import '../serializers/friendica/image_entry_friendica_extensions.dart';
import '../services/gallery_service.dart';
import '../services/network_status_service.dart';
import 'image_viewer_screen.dart';

class GalleryScreen extends StatelessWidget {
  static const thumbnailDimension = 350.0;
  static final _logger = Logger('$GalleryScreen');
  final String galleryName;

  const GalleryScreen({super.key, required this.galleryName});

  @override
  Widget build(BuildContext context) {
    _logger.finest('Building');
    final nss = getIt<NetworkStatusService>();
    final service = context.watch<GalleryService>();
    final body = service.getGallery(galleryName).fold(
          onSuccess: (galleryData) =>
              buildBody(context, service, galleryData.count),
          onError: (error) => buildErrorBody(error.message),
        );
    return Scaffold(
      appBar: StandardAppBar.build(context, galleryName, actions: [
        ValueListenableBuilder(
            valueListenable: nss.imageGalleryLoadingStatus,
            builder: (context2, executing, _) {
              if (executing) {
                final theme = Theme.of(context);
                final size = theme.appBarTheme.actionsIconTheme?.size ??
                    theme.iconTheme.size ??
                    24;
                return Center(
                  child: SizedBox(
                    width: size,
                    height: size,
                    child: CircularProgressIndicator(
                        color: Theme.of(context).canvasColor),
                  ),
                );
              }
              return IconButton(
                  onPressed: () async => await service.updateGalleryImageList(
                        galleryName: galleryName,
                        withNextPage: false,
                        nextPageOnly: false,
                      ),
                  icon: Icon(
                    Icons.refresh,
                  ));
            }),
      ]),
      body: body,
    );
  }

  Widget buildErrorBody(String error) {
    return Center(
      child: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        crossAxisAlignment: CrossAxisAlignment.center,
        children: [
          Text('Error getting images for gallery: $error'),
        ],
      ),
    );
  }

  Widget buildBody(
    BuildContext context,
    GalleryService service,
    int expectedPhotoCount,
  ) {
    final imageResult = service.getGalleryImageList(galleryName);
    if (imageResult.isFailure) {
      return buildErrorBody(imageResult.error.message);
    }

    final images = imageResult.value;
    final attachments = images.map((i) => i.toMediaAttachment()).toList();
    if (images.isEmpty && service.loaded) {
      return Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          crossAxisAlignment: CrossAxisAlignment.center,
          children: const [
            Text('No images'),
          ],
        ),
      );
    }

    if (images.isEmpty) {
      return Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          crossAxisAlignment: CrossAxisAlignment.center,
          children: const [
            Text('Loading images'),
          ],
        ),
      );
    }

    return GridView.builder(
        itemCount: images.length,
        padding: const EdgeInsets.all(5.0),
        gridDelegate: const SliverGridDelegateWithMaxCrossAxisExtent(
            maxCrossAxisExtent: thumbnailDimension),
        itemBuilder: (context, index) {
          final image = images[index];
          if (images.length < expectedPhotoCount &&
              index == images.length - 1) {
            service.updateGalleryImageList(
              galleryName: galleryName,
              withNextPage: true,
              nextPageOnly: true,
            );
          }
          return Padding(
            padding: const EdgeInsets.all(2.0),
            child: GestureDetector(
              onTap: () {
                Navigator.push(context, MaterialPageRoute(builder: (context) {
                  return ImageViewerScreen(
                    attachments: attachments,
                    initialIndex: index,
                  );
                }));
              },
              child: CachedNetworkImage(
                width: thumbnailDimension,
                height: thumbnailDimension,
                imageUrl: image.thumbnailUrl,
              ),
            ),
          );
        });
  }
}