split file_viewer into focused sub-widgets

2026-07-13 00:01:07 +02:00
parent 53bc6d5360
commit 2f5a6b4ce0
6 changed files with 512 additions and 479 deletions
@@ -0,0 +1,99 @@
+import 'package:cached_network_image/cached_network_image.dart';
+import 'package:flutter/material.dart';
+
+import '../../model/account_data.dart';
+import '../../model/endpoint_data.dart';
+import '../../share_intent/remote_file_ref.dart';
+import '../app_progress_indicator.dart';
+
+/// Nextcloud's `/index.php/core/preview` endpoint — returns a rasterized
+/// thumbnail for any file the server has a preview provider for (images,
+/// PDFs with the right backend, Office in some setups). Falls back to an
+/// HTTP 404 when no preview is available, which lets [CachedNetworkImage]
+/// trigger its `errorWidget`. Prefers `fileId` because the path variant
+/// is unreliable on some server configurations.
+String _ncPreviewUrl(RemoteFileRef remote, {int width = 1024}) {
+  final host = EndpointData().nextcloud().full();
+  final id = remote.fileId;
+  final selector = id != null
+      ? 'fileId=$id'
+      : 'file=${Uri.encodeQueryComponent(remote.path)}';
+  return 'https://$host/index.php/core/preview?$selector&x=$width&y=-1&a=1';
+}
+
+/// Header block for the "Vorschau nicht verfügbar" screen.
+///
+/// Two visual modes — kept layout-equivalent so the screen looks identical
+/// whether the server already said "no preview" or the probe failed late:
+///   * **No preview available** (server said no, no remoteFile, or probe
+///     errored): compact "file icon + 'Vorschau nicht verfügbar' text".
+///   * **Preview rendering / loaded**: mid-sized thumbnail without text.
+class UnknownPreviewBlock extends StatefulWidget {
+  final RemoteFileRef? remoteFile;
+  const UnknownPreviewBlock({super.key, required this.remoteFile});
+
+  @override
+  State<UnknownPreviewBlock> createState() => _UnknownPreviewBlockState();
+}
+
+class _UnknownPreviewBlockState extends State<UnknownPreviewBlock> {
+  static const double _previewSize = 180;
+  bool _failed = false;
+
+  Widget _compact(ThemeData theme) => Column(
+    mainAxisSize: MainAxisSize.min,
+    children: [
+      const Icon(Icons.insert_drive_file_outlined, size: 60),
+      const SizedBox(height: 16),
+      Text(
+        'Vorschau nicht verfügbar',
+        style: theme.textTheme.titleMedium,
+        textAlign: TextAlign.center,
+      ),
+    ],
+  );
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = Theme.of(context);
+    final remote = widget.remoteFile;
+    final canProbe =
+        remote != null &&
+        remote.hasPreview != false &&
+        remote.fileId != null &&
+        !_failed;
+    if (!canProbe) return _compact(theme);
+    return SizedBox(
+      width: _previewSize,
+      height: _previewSize,
+      child: CachedNetworkImage(
+        httpHeaders: AccountData().authHeaders(),
+        imageUrl: _ncPreviewUrl(remote, width: 360),
+        fadeInDuration: Duration.zero,
+        fadeOutDuration: Duration.zero,
+        // Late probe failure: re-render into the compact layout so the
+        // screen doesn't keep a 180×180 box around a tiny icon. Deferred
+        // to the next frame because setState during build is illegal.
+        errorListener: (_) {
+          if (!mounted) return;
+          WidgetsBinding.instance.addPostFrameCallback((_) {
+            if (mounted) setState(() => _failed = true);
+          });
+        },
+        placeholder: (_, _) =>
+            const Center(child: AppProgressIndicator.large()),
+        // Briefly empty while the post-frame setState swaps layouts.
+        errorWidget: (_, _, _) => const SizedBox.shrink(),
+        imageBuilder: (_, imageProvider) => ClipRRect(
+          borderRadius: BorderRadius.circular(8),
+          child: Image(
+            image: imageProvider,
+            fit: BoxFit.contain,
+            width: _previewSize,
+            height: _previewSize,
+          ),
+        ),
+      ),
+    );
+  }
+}