merge ambiguously cased directories

lib/model/entry.dart

@@ -4,6 +4,7 @@ import 'dart:ui';
 
 import 'package:aves/geo/countries.dart';
 import 'package:aves/model/entry_cache.dart';
+import 'package:aves/model/entry_dirs.dart';
 import 'package:aves/model/favourites.dart';
 import 'package:aves/model/geotiff.dart';
 import 'package:aves/model/metadata/address.dart';
@@ -31,7 +32,8 @@ class AvesEntry {
   // `sizeBytes`, `dateModifiedSecs` can be missing in viewer mode
   int id;
   String uri;
-  String? _path, _directory, _filename, _extension, _sourceTitle;
+  String? _path, _filename, _extension, _sourceTitle;
+  EntryDir? _directory;
   int? pageId, contentId;
   final String sourceMimeType;
   int width, height, sourceRotationDegrees;
@@ -175,8 +177,8 @@ class AvesEntry {
 
   // directory path, without the trailing separator
   String? get directory {
-    _directory ??= path != null ? pContext.dirname(path!) : null;
+    _directory ??= entryDirRepo.getOrCreate(path != null ? pContext.dirname(path!) : null);
-    return _directory;
+    return _directory!.resolved;
   }
 
   String? get filenameWithoutExtension {

lib/model/entry_dirs.dart

@@ -0,0 +1,68 @@
+import 'dart:async';
+import 'dart:io';
+
+import 'package:aves/services/common/services.dart';
+import 'package:aves/utils/android_file_utils.dart';
+import 'package:collection/collection.dart';
+
+final entryDirRepo = EntryDirRepo._private();
+
+class EntryDirRepo {
+  EntryDirRepo._private();
+
+  // mapping between the raw entry directory path to a resolvable directory
+  final Map<String?, EntryDir> _dirs = {};
+  final StreamController<EntryDir> _ambiguousDirStreamController = StreamController.broadcast();
+
+  Stream<EntryDir> get ambiguousDirStream => _ambiguousDirStreamController.stream;
+
+  // get a resolvable directory for a raw entry directory path
+  EntryDir getOrCreate(String? asIs) {
+    var entryDir = _dirs[asIs];
+    if (entryDir != null) return entryDir;
+
+    final asIsLower = asIs?.toLowerCase();
+    entryDir = _dirs.values.firstWhereOrNull((dir) => dir.asIsLower == asIsLower);
+    if (entryDir != null && !entryDir.ambiguous) {
+      entryDir.ambiguous = true;
+      _ambiguousDirStreamController.add(entryDir);
+    }
+
+    return _dirs.putIfAbsent(asIs, () => entryDir ?? EntryDir(asIs));
+  }
+}
+
+// Some directories are ambiguous because they use different cases,
+// but the OS merge and present them as one directory.
+// This class resolves ambiguous directories to get the directory path
+// with the right case, as presented by the OS.
+class EntryDir {
+  final String? asIs, asIsLower;
+  bool ambiguous = false;
+  String? _resolved;
+
+  EntryDir(this.asIs) : asIsLower = asIs?.toLowerCase();
+
+  String? get resolved {
+    if (!ambiguous) return asIs;
+    if (asIs == null) return null;
+
+    _resolved ??= _resolve();
+    return _resolved;
+  }
+
+  String? _resolve() {
+    final vrl = VolumeRelativeDirectory.fromPath(asIs!);
+    if (vrl == null || vrl.relativeDir.isEmpty) return asIs;
+
+    var resolved = vrl.volumePath;
+    final parts = pContext.split(vrl.relativeDir);
+    for (final part in parts) {
+      final partLower = part.toLowerCase();
+      final childrenDirs = Directory(resolved).listSync().where((v) => v.absolute is Directory).toSet();
+      final found = childrenDirs.firstWhereOrNull((v) => pContext.basename(v.path).toLowerCase() == partLower);
+      resolved = found?.path ?? '$resolved${pContext.separator}$part';
+    }
+    return resolved;
+  }
+}