fix(conversion): preserve Unicode SAF document names

lib/screens/track_metadata_convert.dart

@@ -940,36 +940,11 @@ extension _TrackMetadataConvertAndCueSplit on _TrackMetadataScreenState {
         String relativeDir = '';
         String oldFileName = '';
         if (_isLocalItem) {
-          final uri = Uri.parse(cleanFilePath);
-          final pathSegments = uri.pathSegments;
-          final treeIdx = pathSegments.indexOf('tree');
-          final docIdx = pathSegments.indexOf('document');
-          if (treeIdx >= 0 && treeIdx + 1 < pathSegments.length) {
-            final treeId = pathSegments[treeIdx + 1];
-            treeUri =
-                'content://${uri.authority}/tree/${Uri.encodeComponent(treeId)}';
-          }
-          if (docIdx >= 0 && docIdx + 1 < pathSegments.length) {
-            final docPath = Uri.decodeFull(pathSegments[docIdx + 1]);
-            final slashIdx = docPath.lastIndexOf('/');
-            if (slashIdx >= 0) {
-              oldFileName = docPath.substring(slashIdx + 1);
-              final treeId = treeIdx >= 0 && treeIdx + 1 < pathSegments.length
-                  ? Uri.decodeFull(pathSegments[treeIdx + 1])
-                  : '';
-              if (treeId.isNotEmpty && docPath.startsWith(treeId)) {
-                final afterTree = docPath.substring(treeId.length);
-                final trimmed = afterTree.startsWith('/')
-                    ? afterTree.substring(1)
-                    : afterTree;
-                final lastSlash = trimmed.lastIndexOf('/');
-                relativeDir = lastSlash >= 0
-                    ? trimmed.substring(0, lastSlash)
-                    : '';
-              }
-            } else {
-              oldFileName = docPath;
-            }
+          final location = resolveSafDocumentLocation(cleanFilePath);
+          if (location != null) {
+            treeUri = location.treeUri;
+            relativeDir = location.relativeDir;
+            oldFileName = location.fileName;
           }
         } else {
           treeUri = _downloadItem?.downloadTreeUri;

lib/services/batch_track_actions.dart

@@ -20,6 +20,7 @@ import 'package:spotiflac_android/utils/lyrics_metadata_helper.dart';
 import 'package:spotiflac_android/utils/logger.dart';
 import 'package:spotiflac_android/widgets/batch_convert_sheet.dart';
 import 'package:spotiflac_android/widgets/batch_progress_dialog.dart';
+import 'package:spotiflac_android/utils/saf_display_path.dart';
 
 final _batchActionsLog = AppLogger('BatchActions');
 
@@ -408,48 +409,13 @@ Future<void> _performBatchConversion(
         }
       } else if (isSaf && item.localItem != null) {
         failureStage = 'publish SAF output';
-        final uri = Uri.parse(item.filePath);
-        final pathSegments = uri.pathSegments;
+        final location = resolveSafDocumentLocation(item.filePath);
 
-        String? treeUri;
-        String relativeDir = '';
-        String oldFileName = '';
-
-        final treeIdx = pathSegments.indexOf('tree');
-        final docIdx = pathSegments.indexOf('document');
-        if (treeIdx >= 0 && treeIdx + 1 < pathSegments.length) {
-          final treeId = pathSegments[treeIdx + 1];
-          treeUri =
-              'content://${uri.authority}/tree/${Uri.encodeComponent(treeId)}';
-        }
-        if (docIdx >= 0 && docIdx + 1 < pathSegments.length) {
-          final docPath = Uri.decodeFull(pathSegments[docIdx + 1]);
-          final slashIdx = docPath.lastIndexOf('/');
-          if (slashIdx >= 0) {
-            oldFileName = docPath.substring(slashIdx + 1);
-            final treeId = treeIdx >= 0 && treeIdx + 1 < pathSegments.length
-                ? Uri.decodeFull(pathSegments[treeIdx + 1])
-                : '';
-            if (treeId.isNotEmpty && docPath.startsWith(treeId)) {
-              final afterTree = docPath.substring(treeId.length);
-              final trimmed = afterTree.startsWith('/')
-                  ? afterTree.substring(1)
-                  : afterTree;
-              final lastSlash = trimmed.lastIndexOf('/');
-              relativeDir = lastSlash >= 0
-                  ? trimmed.substring(0, lastSlash)
-                  : '';
-            }
-          } else {
-            oldFileName = docPath;
-          }
-        }
-
-        if (treeUri != null && oldFileName.isNotEmpty) {
+        if (location != null) {
           final published = await ConversionLibraryService.publishSafConversion(
-            treeUri: treeUri,
-            relativeDir: relativeDir,
-            originalFileName: oldFileName,
+            treeUri: location.treeUri,
+            relativeDir: location.relativeDir,
+            originalFileName: location.fileName,
             targetFormat: targetFormat,
             sourcePath: newPath,
             keepOriginal: keepOriginal,

lib/utils/saf_display_path.dart

@@ -1,3 +1,70 @@
+class SafDocumentLocation {
+  final String treeUri;
+  final String relativeDir;
+  final String fileName;
+
+  const SafDocumentLocation({
+    required this.treeUri,
+    required this.relativeDir,
+    required this.fileName,
+  });
+}
+
+/// Resolves the writable tree and relative destination of a SAF document URI.
+///
+/// [Uri.pathSegments] already percent-decodes every segment. Decoding those
+/// values again rejects ordinary Unicode filenames and corrupts literal `%`
+/// characters, so all values below are used directly.
+SafDocumentLocation? resolveSafDocumentLocation(String pathOrUri) {
+  try {
+    final uri = Uri.parse(pathOrUri.trim());
+    if (uri.scheme != 'content' || uri.authority.isEmpty) return null;
+
+    final segments = uri.pathSegments;
+    final treeIndex = segments.indexOf('tree');
+    final documentIndex = segments.indexOf('document');
+    if (treeIndex < 0 ||
+        treeIndex + 1 >= segments.length ||
+        documentIndex < 0 ||
+        documentIndex + 1 >= segments.length) {
+      return null;
+    }
+
+    final treeId = segments[treeIndex + 1];
+    final documentId = segments[documentIndex + 1];
+    if (treeId.isEmpty || documentId.isEmpty) return null;
+
+    final lastSlash = documentId.lastIndexOf('/');
+    final fileName = lastSlash >= 0
+        ? documentId.substring(lastSlash + 1)
+        : documentId;
+    if (fileName.isEmpty) return null;
+
+    var relativeDir = '';
+    final belongsToTree =
+        documentId == treeId || documentId.startsWith('$treeId/');
+    if (belongsToTree) {
+      var relativePath = documentId.substring(treeId.length);
+      if (relativePath.startsWith('/')) {
+        relativePath = relativePath.substring(1);
+      }
+      final relativeSlash = relativePath.lastIndexOf('/');
+      if (relativeSlash >= 0) {
+        relativeDir = relativePath.substring(0, relativeSlash);
+      }
+    }
+
+    return SafDocumentLocation(
+      treeUri:
+          '${uri.scheme}://${uri.authority}/tree/${Uri.encodeComponent(treeId)}',
+      relativeDir: relativeDir,
+      fileName: fileName,
+    );
+  } catch (_) {
+    return null;
+  }
+}
+
 String formatSafUriForDisplay(String pathOrUri) {
   if (pathOrUri.isEmpty || !pathOrUri.startsWith('content://')) {
     return pathOrUri;

test/saf_display_path_test.dart

@@ -2,6 +2,68 @@ import 'package:flutter_test/flutter_test.dart';
 import 'package:spotiflac_android/utils/saf_display_path.dart';
 
 void main() {
+  group('SAF document locations', () {
+    test('keeps Unicode and reserved filename characters decoded once', () {
+      final uri = Uri(
+        scheme: 'content',
+        host: 'com.android.externalstorage.documents',
+        pathSegments: const [
+          'tree',
+          'primary:Music',
+          'document',
+          'primary:Music/Like a Prayer (From “Deadpool & Wolverine”).alac',
+        ],
+      ).toString();
+
+      final location = resolveSafDocumentLocation(uri);
+
+      expect(location, isNotNull);
+      expect(
+        location!.treeUri,
+        'content://com.android.externalstorage.documents/tree/primary%3AMusic',
+      );
+      expect(location.relativeDir, isEmpty);
+      expect(
+        location.fileName,
+        'Like a Prayer (From “Deadpool & Wolverine”).alac',
+      );
+    });
+
+    test('preserves Unicode folders, emoji, and a literal percent sign', () {
+      final uri = Uri(
+        scheme: 'content',
+        host: 'com.android.externalstorage.documents',
+        pathSegments: const [
+          'tree',
+          'primary:Music/Beyoncé',
+          'document',
+          'primary:Music/Beyoncé/日本語/100% & 🎵.flac',
+        ],
+      ).toString();
+
+      final location = resolveSafDocumentLocation(uri);
+
+      expect(location, isNotNull);
+      expect(
+        location!.treeUri,
+        'content://com.android.externalstorage.documents/tree/'
+        'primary%3AMusic%2FBeyonc%C3%A9',
+      );
+      expect(location.relativeDir, '日本語');
+      expect(location.fileName, '100% & 🎵.flac');
+    });
+
+    test('rejects a document URI without writable tree context', () {
+      expect(
+        resolveSafDocumentLocation(
+          'content://com.android.providers.media.documents/'
+          'document/audio%3A12345',
+        ),
+        isNull,
+      );
+    });
+  });
+
   group('SAF display paths', () {
     test('normalizes an external-storage document URI', () {
       const uri =