fix: detect direction notation edits

lib/services/edit_node_change_detector.dart

@@ -0,0 +1,77 @@
+import '../models/pending_upload.dart';
+import '../state/session_state.dart';
+import '../state/settings_state.dart';
+import 'direction_submission_formatter.dart';
+
+/// Detects whether an edit would serialize to a different OSM node.
+class EditNodeChangeDetector {
+  const EditNodeChangeDetector._();
+
+  static bool hasActualChanges(EditNodeSession session) {
+    if (session.extractFromWay) return true;
+
+    const tolerance = 0.0000001;
+    if ((session.target.latitude - session.originalNode.coord.latitude).abs() >
+            tolerance ||
+        (session.target.longitude - session.originalNode.coord.longitude)
+                .abs() >
+            tolerance) {
+      return true;
+    }
+
+    final originalTags = session.originalNode.tags;
+    final submittedTags = _getSubmittedTags(session);
+
+    final originalDirection = _directionValue(originalTags);
+    final submittedDirection =
+        originalDirection == null && session.directions.isEmpty
+        ? null
+        : _directionValue(submittedTags);
+    if (originalDirection != submittedDirection) {
+      return true;
+    }
+
+    return !_tagsEqual(originalTags, submittedTags);
+  }
+
+  static Map<String, String> _getSubmittedTags(EditNodeSession session) {
+    if (session.profile == null) return <String, String>{};
+
+    return PendingUpload(
+      coord: session.target,
+      direction: DirectionSubmissionFormatter.format(
+        session.directions,
+        session.profile,
+      ),
+      profile: session.profile,
+      operatorProfile: session.operatorProfile,
+      refinedTags: session.refinedTags,
+      additionalExistingTags: session.additionalExistingTags,
+      changesetComment: session.changesetComment,
+      uploadMode: UploadMode.production,
+      operation: UploadOperation.modify,
+      originalNodeId: session.originalNode.id,
+    ).getCombinedTags();
+  }
+
+  static String? _directionValue(Map<String, String> tags) =>
+      tags['direction'] ?? tags['camera:direction'];
+
+  static bool _tagsEqual(
+    Map<String, String> originalTags,
+    Map<String, String> submittedTags,
+  ) {
+    final original = Map<String, String>.from(originalTags)
+      ..remove('direction')
+      ..remove('camera:direction');
+    final submitted = Map<String, String>.from(submittedTags)
+      ..remove('direction')
+      ..remove('camera:direction');
+
+    if (original.length != submitted.length) return false;
+    for (final entry in original.entries) {
+      if (submitted[entry.key] != entry.value) return false;
+    }
+    return true;
+  }
+}