Bring back profile subsumption elimination for overpass queries

lib/services/overpass_service.dart

@@ -126,9 +126,24 @@ class OverpassService {
     return ErrorDisposition.retry;
   }
 
-  /// Build Overpass QL query for given bounds and profiles
+  /// Build Overpass QL query for given bounds and profiles.
+  ///
+  /// Profiles are deduplicated first: if one profile's non-empty tags are a
+  /// subset of another's (with identical values), the broader profile's query
+  /// clause already returns every node the narrower one would, so the
+  /// narrower clause is redundant and can be dropped. This directly reduces
+  /// query size/complexity without changing the result set — client-side
+  /// filtering (matching returned nodes against the full profile list) still
+  /// happens independently, so nothing is lost.
   String _buildQuery(LatLngBounds bounds, List<NodeProfile> profiles) {
-    final nodeClauses = profiles.map((profile) {
+    final profilesToQuery = _deduplicateProfilesForQuery(profiles);
+
+    if (profilesToQuery.length < profiles.length) {
+      debugPrint(
+          '[OverpassService] Deduplicated ${profiles.length} profiles to ${profilesToQuery.length} for query efficiency');
+    }
+
+    final nodeClauses = profilesToQuery.map((profile) {
       // Convert profile tags to Overpass filter format, excluding empty values
       final tagFilters = profile.tags.entries
           .where((entry) => entry.value.trim().isNotEmpty)
@@ -149,6 +164,74 @@ out ids;
 ''';
   }
 
+  /// Deduplicate profiles for Overpass queries by removing profiles that are
+  /// subsumed by others. A profile A subsumes profile B if all of A's
+  /// non-empty tags exist in B with identical values — meaning every node
+  /// matching B's filter also matches A's filter, so B's clause is redundant.
+  List<NodeProfile> _deduplicateProfilesForQuery(List<NodeProfile> profiles) {
+    if (profiles.length <= 1) return profiles;
+
+    final result = <NodeProfile>[];
+
+    for (final candidate in profiles) {
+      // Skip profiles that only have empty tags - they would match
+      // everything and shouldn't be treated as subsuming or subsumable.
+      final candidateNonEmptyTags = candidate.tags.entries
+          .where((entry) => entry.value.trim().isNotEmpty)
+          .toList();
+
+      if (candidateNonEmptyTags.isEmpty) continue;
+
+      // Check if any existing profile in our result subsumes this candidate
+      bool isSubsumed = false;
+      for (final existing in result) {
+        if (_profileSubsumes(existing, candidate)) {
+          isSubsumed = true;
+          break;
+        }
+      }
+
+      if (!isSubsumed) {
+        // This candidate is not subsumed, so add it. But first, remove any
+        // existing profiles that this candidate subsumes (candidate is
+        // broader, so those clauses are now redundant).
+        result.removeWhere((existing) => _profileSubsumes(candidate, existing));
+        result.add(candidate);
+      }
+    }
+
+    // Safety check: if dedup removed everything (e.g. all-empty-tag
+    // profiles), fall back to the original list rather than sending an
+    // empty query.
+    return result.isNotEmpty ? result : profiles;
+  }
+
+  /// Check if [broaderProfile] subsumes [specificProfile]: true if all
+  /// non-empty tags in [broaderProfile] exist in [specificProfile] with
+  /// identical values.
+  bool _profileSubsumes(NodeProfile broaderProfile, NodeProfile specificProfile) {
+    final broaderTags = Map.fromEntries(
+      broaderProfile.tags.entries.where((entry) => entry.value.trim().isNotEmpty),
+    );
+    final specificTags = Map.fromEntries(
+      specificProfile.tags.entries.where((entry) => entry.value.trim().isNotEmpty),
+    );
+
+    // If broader has no non-empty tags, it doesn't subsume anything (it
+    // would match everything, which isn't a meaningful "broader filter").
+    if (broaderTags.isEmpty) return false;
+
+    // If broader has more non-empty tags than specific, it can't subsume it.
+    if (broaderTags.length > specificTags.length) return false;
+
+    for (final entry in broaderTags.entries) {
+      if (specificTags[entry.key] != entry.value) return false;
+    }
+
+    return true;
+  }
+
+
   /// Parse Overpass JSON response into OsmNode objects
   List<OsmNode> _parseResponse(String responseBody) {
     final data = jsonDecode(responseBody) as Map<String, dynamic>;