implemented a comprehensive Nextcloud file sharing system with support for user, group, and public link shares with gating based on server-side permissions; added sharing management interfaces including a share sheet; updated the file list with visual badges for incoming shares and improved OCS API response handling.

lib/api/marianumcloud/autocomplete/autocomplete_api.dart

@@ -3,25 +3,39 @@ import 'dart:io';
 
 import 'package:http/http.dart' as http;
 
+import '../../../model/endpoint_data.dart';
+import '../../errors/server_exception.dart';
 import '../nextcloud_ocs.dart';
 import 'autocomplete_response.dart';
 
 class AutocompleteApi {
-  Future<AutocompleteResponse> find(String query) async {
-    final endpoint = NextcloudOcs.uri(
-      'core/autocomplete/get',
-      queryParameters: {
+  /// Searches sharees (users by default). Pass [shareTypes] to widen the search
+  /// — e.g. `[0, 1]` for both users and groups (0 = user, 1 = group).
+  Future<AutocompleteResponse> find(
+    String query, {
+    List<int> shareTypes = const [0],
+  }) async {
+    // NextcloudOcs.uri serialises every query value via `toString()`, which
+    // would turn the `shareTypes[]` list into `"[0, 1]"`. Build the Uri here so
+    // Dart encodes the list as repeated `shareTypes[]=0&shareTypes[]=1` params.
+    final endpoint = EndpointData().nextcloud();
+    final uri = Uri.https(
+      endpoint.domain,
+      '${endpoint.path}/ocs/v2.php/core/autocomplete/get',
+      {
+        'format': 'json',
         'search': query,
         'itemType': ' ',
         'itemId': ' ',
-        'shareTypes[]': ['0'],
+        'shareTypes[]': shareTypes.map((t) => t.toString()).toList(),
         'limit': '10',
       },
     );
-    final response = await http.get(endpoint, headers: NextcloudOcs.headers());
+    final response = await http.get(uri, headers: NextcloudOcs.headers());
     if (response.statusCode != HttpStatus.ok) {
-      throw Exception(
-        'Api call failed with ${response.statusCode}: ${response.body}',
+      throw ServerException(
+        statusCode: response.statusCode,
+        technicalDetails: 'core/autocomplete/get: ${response.body}',
       );
     }
     final decoded = jsonDecode(response.body) as Map<String, dynamic>;

lib/api/marianumcloud/autocomplete/autocomplete_response.dart

@@ -1,7 +1,17 @@
 import 'package:json_annotation/json_annotation.dart';
 
+import '../files_sharing/queries/share/share.dart';
+
 part 'autocomplete_response.g.dart';
 
+/// Maps an autocomplete result's `source` to the matching Nextcloud share type.
+/// Groups become [kShareTypeGroup]; everything else (users, and any unknown
+/// source) defaults to [kShareTypeUser].
+int shareTypeFromSource(String? source) {
+  if (source != null && source.startsWith('groups')) return kShareTypeGroup;
+  return kShareTypeUser;
+}
+
 @JsonSerializable(explicitToJson: true)
 class AutocompleteResponse {
   List<AutocompleteResponseObject> data;

lib/api/marianumcloud/capabilities/get_nextcloud_capabilities.dart

@@ -0,0 +1,46 @@
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:http/http.dart' as http;
+
+import '../../errors/server_exception.dart';
+import '../nextcloud_ocs.dart';
+import 'nextcloud_sharing_capabilities.dart';
+
+/// Fetches the current user's Nextcloud capabilities via OCS
+/// `GET cloud/capabilities` and extracts the `files_sharing` block. This is the
+/// per-user, group-aware source of truth the sharing UI gates on — no custom
+/// backend involved.
+class GetNextcloudCapabilities {
+  Future<NextcloudSharingCapabilities> run() async {
+    final endpoint = NextcloudOcs.uri(
+      'cloud/capabilities',
+      queryParameters: {'format': 'json'},
+    );
+    final response = await http.get(endpoint, headers: NextcloudOcs.headers());
+    if (response.statusCode != HttpStatus.ok) {
+      throw ServerException(
+        statusCode: response.statusCode,
+        technicalDetails: 'cloud/capabilities: ${response.body}',
+      );
+    }
+    final decoded = jsonDecode(response.body) as Map<String, dynamic>;
+    final data =
+        (decoded['ocs'] as Map<String, dynamic>?)?['data']
+            as Map<String, dynamic>?;
+    final capabilities = data?['capabilities'] as Map<String, dynamic>?;
+    final filesSharing = capabilities?['files_sharing'];
+    if (filesSharing is! Map<String, dynamic>) {
+      // Server doesn't advertise files_sharing (app disabled) — treat as no
+      // sharing capability rather than failing the whole load.
+      return const NextcloudSharingCapabilities();
+    }
+    final passwordPolicy = capabilities?['password_policy'];
+    return NextcloudSharingCapabilities.fromFilesSharing(
+      filesSharing,
+      passwordPolicy: passwordPolicy is Map<String, dynamic>
+          ? passwordPolicy
+          : null,
+    );
+  }
+}

lib/api/marianumcloud/capabilities/nextcloud_sharing_capabilities.dart

@@ -0,0 +1,131 @@
+/// Subset of Nextcloud's `files_sharing` capabilities block that the mobile
+/// sharing UI gates on. Nextcloud reports these per authenticated user, so a
+/// group that an admin excluded from creating public links sees
+/// `public.enabled == false` here — exactly how the web UI hides those buttons.
+///
+/// The block is deeply nested and varies between server versions, so this is
+/// parsed by hand from the raw OCS map with safe fallbacks rather than via
+/// code generation. Missing fields default to the most restrictive value so a
+/// newer/older server never accidentally unlocks a capability.
+class NextcloudSharingCapabilities {
+  /// `files_sharing.api_enabled` — master switch. When false the user may not
+  /// create any share (user, group or link).
+  final bool apiEnabled;
+
+  /// `files_sharing.public.enabled` — public link shares allowed.
+  final bool publicEnabled;
+
+  /// `files_sharing.public.multiple_links` — more than one link per file.
+  final bool publicMultipleLinks;
+
+  /// `files_sharing.public.upload` — public upload / file-drop folders.
+  final bool publicUploadEnabled;
+
+  /// `files_sharing.public.password.enforced` — a password is mandatory on
+  /// public links, so the create flow must collect one upfront.
+  final bool publicPasswordEnforced;
+
+  /// `files_sharing.public.expire_date.enabled`.
+  final bool publicExpireEnabled;
+
+  /// `files_sharing.public.expire_date.days` — default/maximum lifetime.
+  final int? publicExpireDays;
+
+  /// `files_sharing.public.expire_date.enforced` — expiry cannot be removed.
+  final bool publicExpireEnforced;
+
+  /// `files_sharing.group.enabled` (falls back to the older `group_sharing`).
+  final bool groupEnabled;
+
+  /// `files_sharing.resharing` — recipients may reshare.
+  final bool resharing;
+
+  // --- password_policy (a sibling capability of files_sharing) ---
+  // These let the link-password UI state the rules up front instead of only
+  // surfacing them after the server rejects a weak password. The
+  // "non-common password" (breach) check can only be enforced server-side.
+
+  /// `password_policy.minLength`.
+  final int? passwordMinLength;
+
+  /// `password_policy.enforceUpperLowerCase`.
+  final bool passwordEnforceUpperLower;
+
+  /// `password_policy.enforceNumericCharacters`.
+  final bool passwordEnforceNumeric;
+
+  /// `password_policy.enforceSpecialCharacters`.
+  final bool passwordEnforceSpecial;
+
+  const NextcloudSharingCapabilities({
+    this.apiEnabled = false,
+    this.publicEnabled = false,
+    this.publicMultipleLinks = false,
+    this.publicUploadEnabled = false,
+    this.publicPasswordEnforced = false,
+    this.publicExpireEnabled = false,
+    this.publicExpireDays,
+    this.publicExpireEnforced = false,
+    this.groupEnabled = false,
+    this.resharing = false,
+    this.passwordMinLength,
+    this.passwordEnforceUpperLower = false,
+    this.passwordEnforceNumeric = false,
+    this.passwordEnforceSpecial = false,
+  });
+
+  /// Parses the `files_sharing` sub-map of an OCS `cloud/capabilities`
+  /// response, plus the optional sibling `password_policy` map. Tolerates
+  /// missing intermediate maps and type drift.
+  factory NextcloudSharingCapabilities.fromFilesSharing(
+    Map<String, dynamic> filesSharing, {
+    Map<String, dynamic>? passwordPolicy,
+  }) {
+    Map<String, dynamic>? sub(Map<String, dynamic>? m, String key) {
+      final value = m?[key];
+      return value is Map<String, dynamic> ? value : null;
+    }
+
+    bool boolAt(Map<String, dynamic>? m, String key) => m?[key] == true;
+    int? intAt(Map<String, dynamic>? m, String key) {
+      final v = m?[key];
+      if (v is int) return v;
+      if (v is String) return int.tryParse(v);
+      return null;
+    }
+
+    final public = sub(filesSharing, 'public');
+    final password = sub(public, 'password');
+    final expire = sub(public, 'expire_date');
+    final group = sub(filesSharing, 'group');
+
+    return NextcloudSharingCapabilities(
+      apiEnabled: boolAt(filesSharing, 'api_enabled'),
+      publicEnabled: boolAt(public, 'enabled'),
+      publicMultipleLinks: boolAt(public, 'multiple_links'),
+      publicUploadEnabled: boolAt(public, 'upload'),
+      publicPasswordEnforced: boolAt(password, 'enforced'),
+      publicExpireEnabled: boolAt(expire, 'enabled'),
+      publicExpireDays: intAt(expire, 'days'),
+      publicExpireEnforced: boolAt(expire, 'enforced'),
+      // Newer servers nest it under `group.enabled`; older ones expose a flat
+      // `group_sharing` boolean.
+      groupEnabled:
+          boolAt(group, 'enabled') || boolAt(filesSharing, 'group_sharing'),
+      resharing: boolAt(filesSharing, 'resharing'),
+      passwordMinLength: intAt(passwordPolicy, 'minLength'),
+      passwordEnforceUpperLower: boolAt(
+        passwordPolicy,
+        'enforceUpperLowerCase',
+      ),
+      passwordEnforceNumeric: boolAt(
+        passwordPolicy,
+        'enforceNumericCharacters',
+      ),
+      passwordEnforceSpecial: boolAt(
+        passwordPolicy,
+        'enforceSpecialCharacters',
+      ),
+    );
+  }
+}

lib/api/marianumcloud/files_sharing/file_sharing_api.dart

@@ -1,21 +1,144 @@
-import 'dart:io';
+import 'dart:convert';
 
 import 'package:http/http.dart' as http;
 
+import '../../errors/server_exception.dart';
 import '../nextcloud_ocs.dart';
 import 'file_sharing_api_params.dart';
+import 'queries/share/share.dart';
+import 'queries/share/share_update_params.dart';
 
+/// OCS `files_sharing` API (Nextcloud Sharing API v1). Per the official docs:
+/// list/delete pass parameters via the URL (query / path), create and update
+/// pass them in the request **body** (form-urlencoded), and every call adds
+/// `format=json` so the server replies with JSON instead of XML.
+///
+/// All calls surface failures as [ServerException] so they map to friendly
+/// messages via `errorToUserMessage`.
 class FileSharingApi {
-  Future<void> share(FileSharingApiParams query) async {
+  static const String _base = 'apps/files_sharing/api/v1/shares';
+
+  /// Creates a share. Returns the created [Share] (callers that don't need it —
+  /// e.g. Talk file sharing — can ignore the result).
+  Future<Share> share(FileSharingApiParams query) async {
     final endpoint = NextcloudOcs.uri(
-      'apps/files_sharing/api/v1/shares',
-      queryParameters: query.toJson(),
+      _base,
+      queryParameters: {'format': 'json'},
     );
-    final response = await http.post(endpoint, headers: NextcloudOcs.headers());
-    if (response.statusCode != HttpStatus.ok) {
-      throw Exception(
-        'Api call failed with ${response.statusCode}: ${response.body}',
+    final response = await http.post(
+      endpoint,
+      headers: NextcloudOcs.headers(),
+      body: _stringForm(query.toJson()),
+    );
+    return _decodeShare(response, action: 'Freigabe erstellen');
+  }
+
+  /// Lists shares for the given OCS [path] (see `ocs_path.dart`). [reshares]
+  /// includes shares the current user received and re-shared.
+  Future<List<Share>> listForPath(String path, {bool reshares = false}) async {
+    final endpoint = NextcloudOcs.uri(
+      _base,
+      queryParameters: {
+        'format': 'json',
+        'path': path,
+        'reshares': reshares.toString(),
+        'subfiles': 'false',
+      },
+    );
+    final response = await http.get(endpoint, headers: NextcloudOcs.headers());
+    final data = _decodeData(response, action: 'Freigaben laden');
+    if (data is! List) return const [];
+    return data
+        .whereType<Map<String, dynamic>>()
+        .map(Share.fromJson)
+        .toList(growable: false);
+  }
+
+  /// Updates an existing share. Returns the updated [Share].
+  Future<Share> update(int shareId, ShareUpdateParams params) async {
+    final endpoint = NextcloudOcs.uri(
+      '$_base/$shareId',
+      queryParameters: {'format': 'json'},
+    );
+    final response = await http.put(
+      endpoint,
+      headers: NextcloudOcs.headers(),
+      body: params.toQuery(),
+    );
+    return _decodeShare(response, action: 'Freigabe ändern');
+  }
+
+  /// Deletes (revokes) a share.
+  Future<void> remove(int shareId) async {
+    final endpoint = NextcloudOcs.uri(
+      '$_base/$shareId',
+      queryParameters: {'format': 'json'},
+    );
+    final response = await http.delete(
+      endpoint,
+      headers: NextcloudOcs.headers(),
+    );
+    _decodeData(response, action: 'Freigabe löschen');
+  }
+
+  /// Stringifies a json map into form fields (the OCS body is
+  /// `application/x-www-form-urlencoded`). Null values are already dropped by
+  /// the params' `includeIfNull: false`.
+  Map<String, String> _stringForm(Map<String, dynamic> json) =>
+      json.map((key, value) => MapEntry(key, value.toString()));
+
+  /// Decodes a single-share response (create/update). Throws if the payload is
+  /// not a share object.
+  Share _decodeShare(http.Response response, {required String action}) {
+    final data = _decodeData(response, action: action);
+    if (data is! Map<String, dynamic>) {
+      throw ServerException(
+        statusCode: response.statusCode,
+        technicalDetails: 'Unerwartete Antwort für "$action": ${response.body}',
       );
     }
+    return Share.fromJson(data);
+  }
+
+  /// Validates the HTTP/OCS envelope and returns the `ocs.data` payload, or
+  /// throws a [ServerException] carrying the server's OCS message when present.
+  ///
+  /// Every access is type-checked rather than cast: PHP's `json_encode` turns
+  /// an empty associative array into a JSON array (`[]`), and `statuscode` can
+  /// arrive as a string — a hard `as` cast on either would throw a raw
+  /// TypeError that surfaces as the generic "something went wrong" message.
+  Object? _decodeData(http.Response response, {required String action}) {
+    dynamic decoded;
+    try {
+      decoded = jsonDecode(response.body);
+    } catch (_) {
+      decoded = null;
+    }
+    final ocs = decoded is Map<String, dynamic> ? decoded['ocs'] : null;
+    final ocsMap = ocs is Map<String, dynamic> ? ocs : null;
+    final meta = ocsMap?['meta'];
+    final metaMap = meta is Map<String, dynamic> ? meta : null;
+
+    final rawStatus = metaMap?['statuscode'];
+    final ocsStatus = rawStatus is int
+        ? rawStatus
+        : (rawStatus is String ? int.tryParse(rawStatus) : null);
+    final rawMessage = metaMap?['message'];
+    final ocsMessage = rawMessage is String ? rawMessage : null;
+
+    // OCS v2 mirrors the HTTP status; accept any 2xx. Success OCS statuscodes
+    // are 100 (v1 carry-over) or 200.
+    final httpOk = response.statusCode >= 200 && response.statusCode < 300;
+    final ocsOk = ocsStatus == null || ocsStatus == 100 || ocsStatus == 200;
+    if (!httpOk || !ocsOk) {
+      throw ServerException(
+        statusCode: response.statusCode,
+        userMessage: ocsMessage != null && ocsMessage.isNotEmpty
+            ? '$action fehlgeschlagen: $ocsMessage'
+            : null,
+        technicalDetails: '$action: ${response.statusCode} ${response.body}',
+      );
+    }
+    return ocsMap?['data'];
   }
 }

lib/api/marianumcloud/files_sharing/file_sharing_api_params.dart

@@ -2,7 +2,10 @@ import 'package:json_annotation/json_annotation.dart';
 
 part 'file_sharing_api_params.g.dart';
 
-@JsonSerializable()
+// includeIfNull:false so the optional sharing fields below are only sent when
+// set — otherwise the OCS query would carry `permissions=null` etc. and be
+// rejected.
+@JsonSerializable(includeIfNull: false)
 class FileSharingApiParams {
   int shareType;
   String shareWith;
@@ -10,12 +13,24 @@ class FileSharingApiParams {
   String? referenceId;
   String? talkMetaData;
 
+  /// Permission bitmask (see `share_permissions.dart`).
+  int? permissions;
+
+  /// Public link password.
+  String? password;
+
+  /// Expiry as `YYYY-MM-DD`.
+  String? expireDate;
+
   FileSharingApiParams({
     required this.shareType,
     required this.shareWith,
     required this.path,
     this.referenceId,
     this.talkMetaData,
+    this.permissions,
+    this.password,
+    this.expireDate,
   });
 
   factory FileSharingApiParams.fromJson(Map<String, dynamic> json) =>

lib/api/marianumcloud/files_sharing/file_sharing_api_params.g.dart

@@ -14,6 +14,9 @@ FileSharingApiParams _$FileSharingApiParamsFromJson(
   path: json['path'] as String,
   referenceId: json['referenceId'] as String?,
   talkMetaData: json['talkMetaData'] as String?,
+  permissions: (json['permissions'] as num?)?.toInt(),
+  password: json['password'] as String?,
+  expireDate: json['expireDate'] as String?,
 );
 
 Map<String, dynamic> _$FileSharingApiParamsToJson(
@@ -22,6 +25,9 @@ Map<String, dynamic> _$FileSharingApiParamsToJson(
   'shareType': instance.shareType,
   'shareWith': instance.shareWith,
   'path': instance.path,
-  'referenceId': instance.referenceId,
-  'talkMetaData': instance.talkMetaData,
+  'referenceId': ?instance.referenceId,
+  'talkMetaData': ?instance.talkMetaData,
+  'permissions': ?instance.permissions,
+  'password': ?instance.password,
+  'expireDate': ?instance.expireDate,
 };

lib/api/marianumcloud/files_sharing/ocs_path.dart

@@ -0,0 +1,18 @@
+import '../webdav/queries/list_files/cacheable_file.dart';
+
+/// Converts a [CacheableFile.path] (relative to the WebDAV files root, folders
+/// ending in `/`) into the path the OCS `files_sharing` API expects: rooted
+/// with a single leading slash and without a trailing slash on folders.
+///
+/// Examples:
+///   ''                  -> '/'           (files root)
+///   'Documents/x.pdf'   -> '/Documents/x.pdf'
+///   'Documents/'        -> '/Documents'
+///   '/Shared/a/'        -> '/Shared/a'
+String ocsPathFor(String webdavPath) {
+  final trimmed = webdavPath.replaceAll(RegExp(r'^/+|/+$'), '');
+  return trimmed.isEmpty ? '/' : '/$trimmed';
+}
+
+/// Convenience wrapper for a [CacheableFile].
+String ocsPathOf(CacheableFile file) => ocsPathFor(file.path);

lib/api/marianumcloud/files_sharing/queries/share/share.dart

@@ -0,0 +1,108 @@
+/// Nextcloud share types (subset the app uses).
+const int kShareTypeUser = 0;
+const int kShareTypeGroup = 1;
+const int kShareTypePublicLink = 3;
+const int kShareTypeEmail = 4;
+
+/// A Talk conversation ("room") the file is linked into.
+const int kShareTypeRoom = 10;
+
+/// A single share as returned by the OCS `files_sharing` API.
+///
+/// Parsed by hand rather than via code generation: OCS is inconsistent about
+/// types across versions (e.g. `id`/`share_type` may arrive as either strings
+/// or numbers) and omits optional fields entirely, so defensive parsing is
+/// safer than generated `as int` casts.
+class Share {
+  final int id;
+  final int shareType;
+  final int permissions;
+
+  /// Server path of the shared item (e.g. `/Documents/x.pdf`).
+  final String? path;
+
+  /// `'file'` or `'folder'`.
+  final String? itemType;
+
+  /// Recipient id (user/group id); empty for public links.
+  final String? shareWith;
+  final String? shareWithDisplayname;
+
+  /// Public link URL (only set for [kShareTypePublicLink]).
+  final String? url;
+
+  /// Raw expiration as `"YYYY-MM-DD HH:MM:SS"` (or null when none).
+  final String? expiration;
+  final String? label;
+
+  /// Redacted password marker: the server returns `null` when no password is
+  /// set and a placeholder (`"redacted"`) when one is — never the real value.
+  final String? password;
+
+  const Share({
+    required this.id,
+    required this.shareType,
+    required this.permissions,
+    this.path,
+    this.itemType,
+    this.shareWith,
+    this.shareWithDisplayname,
+    this.url,
+    this.expiration,
+    this.label,
+    this.password,
+  });
+
+  bool get isPublicLink => shareType == kShareTypePublicLink;
+  bool get isGroup => shareType == kShareTypeGroup;
+  bool get isEmail => shareType == kShareTypeEmail;
+  bool get isRoom => shareType == kShareTypeRoom;
+  bool get isFolder => itemType == 'folder';
+
+  /// Whether a (link) password is currently set. See [password].
+  bool get hasPassword => password != null && password!.isNotEmpty;
+
+  /// Best display title for the share row.
+  String get displayTitle {
+    if (isPublicLink) return label?.isNotEmpty == true ? label! : 'Link';
+    final name = shareWithDisplayname;
+    if (name != null && name.isNotEmpty) return name;
+    return shareWith ?? 'Unbekannt';
+  }
+
+  /// Human label for the kind of share (for subtitles/headers).
+  String get kindLabel {
+    if (isPublicLink) return 'Öffentlicher Link';
+    if (isGroup) return 'Gruppe';
+    if (isRoom) return 'Talk-Chat';
+    if (isEmail) return 'E-Mail';
+    if (shareType == kShareTypeUser) return 'Person';
+    return 'Freigabe';
+  }
+
+  static int _asInt(Object? value, {int fallback = 0}) {
+    if (value is int) return value;
+    if (value is String) return int.tryParse(value) ?? fallback;
+    return fallback;
+  }
+
+  static String? _asString(Object? value) {
+    if (value == null) return null;
+    final s = value.toString();
+    return s.isEmpty ? null : s;
+  }
+
+  factory Share.fromJson(Map<String, dynamic> json) => Share(
+    id: _asInt(json['id']),
+    shareType: _asInt(json['share_type']),
+    permissions: _asInt(json['permissions']),
+    path: _asString(json['path']),
+    itemType: _asString(json['item_type']),
+    shareWith: _asString(json['share_with']),
+    shareWithDisplayname: _asString(json['share_with_displayname']),
+    url: _asString(json['url']),
+    expiration: _asString(json['expiration']),
+    label: _asString(json['label']),
+    password: _asString(json['password']),
+  );
+}

lib/api/marianumcloud/files_sharing/queries/share/share_update_params.dart

@@ -0,0 +1,20 @@
+/// Parameters for updating an existing share via OCS `PUT shares/{id}`.
+/// Only the fields that are explicitly set are sent — every field is optional
+/// and a null is omitted from the request (sending `permissions=null` would be
+/// rejected by the server).
+///
+/// Use an empty string for [expireDate]/[password] to explicitly clear the
+/// value server-side (Nextcloud treats `expireDate=` as "remove expiry").
+class ShareUpdateParams {
+  final int? permissions;
+  final String? password;
+  final String? expireDate;
+
+  const ShareUpdateParams({this.permissions, this.password, this.expireDate});
+
+  Map<String, String> toQuery() => {
+    if (permissions != null) 'permissions': permissions.toString(),
+    'password': ?password,
+    'expireDate': ?expireDate,
+  };
+}

lib/api/marianumcloud/files_sharing/share_permissions.dart

@@ -0,0 +1,82 @@
+/// Nextcloud share permission bitmask helpers. These mirror the constants the
+/// OCS `files_sharing` API expects in the `permissions` field. Kept as pure
+/// functions (no Flutter/IO) so they are unit-testable.
+library;
+
+/// Individual permission bits (Nextcloud `OCS\Constants`).
+const int kPermissionRead = 1;
+const int kPermissionUpdate = 2;
+const int kPermissionCreate = 4;
+const int kPermissionDelete = 8;
+const int kPermissionShare = 16;
+
+/// User-facing presets that map onto a bitmask.
+enum SharePreset {
+  /// Recipient can only view/download.
+  readOnly,
+
+  /// Recipient can view, edit, add and remove (full editing).
+  edit,
+
+  /// Upload-only "file request" — recipient can add files to a folder but not
+  /// see existing contents. Only meaningful for folders.
+  fileDrop,
+}
+
+extension SharePresetLabel on SharePreset {
+  String get label {
+    switch (this) {
+      case SharePreset.readOnly:
+        return 'Nur Lesen';
+      case SharePreset.edit:
+        return 'Bearbeiten';
+      case SharePreset.fileDrop:
+        return 'Datei-Anfrage';
+    }
+  }
+}
+
+/// Returns true if [mask] contains the given [flag].
+bool hasPermission(int mask, int flag) => mask & flag == flag;
+
+/// Builds the permission bitmask for a [preset].
+///
+/// [isFolder] matters for the `edit` preset: a file can only carry
+/// read+update, while a folder additionally supports create+delete. Nextcloud
+/// rejects create/delete on a file ("Failed to update share"), so they must be
+/// omitted there. When [allowReshare] is true the reshare bit is added to the
+/// editing presets — mirroring how the Nextcloud clients respect the
+/// `resharing` capability.
+int permissionsFor(
+  SharePreset preset, {
+  bool allowReshare = false,
+  bool isFolder = false,
+}) {
+  switch (preset) {
+    case SharePreset.readOnly:
+      return kPermissionRead;
+    case SharePreset.edit:
+      var base = kPermissionRead | kPermissionUpdate;
+      if (isFolder) base |= kPermissionCreate | kPermissionDelete;
+      return allowReshare ? base | kPermissionShare : base;
+    case SharePreset.fileDrop:
+      return kPermissionCreate;
+  }
+}
+
+/// Classifies an arbitrary permission bitmask into the closest preset, or null
+/// if it doesn't match any (e.g. a custom combination). The reshare bit is
+/// ignored for matching so an "edit" share stays "edit" regardless of reshare.
+SharePreset? presetFromBitmask(int mask) {
+  final normalized = mask & ~kPermissionShare;
+  if (normalized == kPermissionCreate) return SharePreset.fileDrop;
+  if (normalized == kPermissionRead) return SharePreset.readOnly;
+  // Any read share that also carries a write bit (update/create/delete) is
+  // surfaced as "edit".
+  const writeBits = kPermissionUpdate | kPermissionCreate | kPermissionDelete;
+  if (hasPermission(normalized, kPermissionRead) &&
+      normalized & writeBits != 0) {
+    return SharePreset.edit;
+  }
+  return null;
+}

lib/api/marianumcloud/webdav/queries/list_files/cacheable_file.dart

@@ -24,6 +24,11 @@ class CacheableFile {
   /// when a preview is going to load anyway.
   bool? hasPreview;
 
+  /// True when this entry is an incoming share — i.e. shared with the current
+  /// user by someone else (`nc:mount-type == 'shared'`). Used to badge the
+  /// file/folder in the list. Nullable so older cached entries decode fine.
+  bool? isSharedWithMe;
+
   CacheableFile({
     required this.path,
     required this.isDirectory,
@@ -35,6 +40,7 @@ class CacheableFile {
     this.modifiedAt,
     this.fileId,
     this.hasPreview,
+    this.isSharedWithMe,
   });
 
   CacheableFile.fromDavFile(WebDavFile file) {
@@ -48,6 +54,11 @@ class CacheableFile {
     modifiedAt = file.lastModified;
     fileId = int.tryParse(file.fileId ?? '');
     hasPreview = file.hasPreview;
+    // Incoming share: the item is mounted into the user's files by someone
+    // else. Outgoing shares ([isSharedByMe]) can't be derived from WebDAV with
+    // the pinned package, so they are filled in by ListFiles via one OCS call
+    // per folder.
+    isSharedWithMe = file.props.ncmounttype == 'shared';
   }
 
   factory CacheableFile.fromJson(Map<String, dynamic> json) =>

lib/api/marianumcloud/webdav/queries/list_files/cacheable_file.g.dart

@@ -22,6 +22,7 @@ CacheableFile _$CacheableFileFromJson(Map<String, dynamic> json) =>
           : DateTime.parse(json['modifiedAt'] as String),
       fileId: (json['fileId'] as num?)?.toInt(),
       hasPreview: json['hasPreview'] as bool?,
+      isSharedWithMe: json['isSharedWithMe'] as bool?,
     );
 
 Map<String, dynamic> _$CacheableFileToJson(CacheableFile instance) =>
@@ -36,4 +37,5 @@ Map<String, dynamic> _$CacheableFileToJson(CacheableFile instance) =>
       'modifiedAt': instance.modifiedAt?.toIso8601String(),
       'fileId': instance.fileId,
       'hasPreview': instance.hasPreview,
+      'isSharedWithMe': instance.isSharedWithMe,
     };

lib/api/marianumcloud/webdav/queries/list_files/list_files.dart

@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:nextcloud/nextcloud.dart';
 
 import '../../webdav_api.dart';
@@ -37,19 +39,46 @@ class ListFiles extends WebdavApi<ListFilesParams> {
       ocsize: true,
       nccreationtime: true,
       nchaspreview: true,
+      // 'shared' here means an incoming share (mounted into the user's files
+      // by someone else); used to badge those entries in the list.
+      ncmounttype: true,
     );
+
+    var files = await _fetch(webdav, prop, timeout);
+    // A freshly-entered incoming share sometimes answers its first PROPFIND
+    // without the OC/NC props (no fileid / has-preview / mount-type) while the
+    // share mount warms up server-side — which drops thumbnails AND share
+    // badges together. Retry a couple of times so the folder self-heals
+    // instead of needing manual re-entry.
+    for (var attempt = 0; attempt < 2 && _looksIncomplete(files); attempt++) {
+      await Future<void>.delayed(const Duration(milliseconds: 700));
+      files = await _fetch(webdav, prop, timeout);
+    }
+
+    return ListFilesResponse(files);
+  }
+
+  Future<Set<CacheableFile>> _fetch(
+    WebDavClient webdav,
+    WebDavPropWithoutValues prop,
+    Duration timeout,
+  ) async {
     final davFiles =
         (await webdav
                 .propfind(PathUri.parse(params.path), prop: prop)
                 .timeout(timeout))
             .toWebDavFiles();
     final files = davFiles.map(CacheableFile.fromDavFile).toSet();
-
     // somehow the current working folder is also listed, it is filtered here.
     files.removeWhere(
       (element) => element.path == '/${params.path}/' || element.path == '/',
     );
-
-    return ListFilesResponse(files);
+    return files;
   }
+
+  /// True when the server returned entries but none carry a `fileId` — a sign
+  /// the OC/NC properties were omitted (cold share mount), so thumbnails and
+  /// share badges would be missing for the whole folder.
+  bool _looksIncomplete(Set<CacheableFile> files) =>
+      files.isNotEmpty && files.every((file) => file.fileId == null);
 }

lib/api/marianumcloud/webdav/queries/list_files/list_files_cache.dart

@@ -40,9 +40,7 @@ class ListFilesCache extends SimpleCache<ListFilesResponse> {
   /// [invalidate].
   static int _cacheTimeFor(String path) {
     final stripped = path.replaceAll('/', '').trim();
-    return stripped.isEmpty
-        ? RequestCache.cacheDay
-        : RequestCache.cacheNothing;
+    return stripped.isEmpty ? RequestCache.cacheDay : RequestCache.cacheNothing;
   }
 
   /// Triggers a root-listing fetch in the background if no cached payload