better metadata processing

lib/rugreefer.dart

@@ -6,16 +6,19 @@ import 'package:turf/turf.dart';
 import 'package:path_provider/path_provider.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 import 'package:flutter/foundation.dart' show kIsWeb;
+import 'package:flutter/services.dart' show rootBundle;
 
 class RugReefer {
   final String apiUrl;
   final bool enableCacheExpiration;
   final Duration cacheExpirationDuration;
   final http.Client httpClient;
+  final String categoryMap;
   Directory? cacheDir;
 
   RugReefer({
     required this.apiUrl,
+    required this.categoryMap,
     this.enableCacheExpiration = false,
     this.cacheExpirationDuration = const Duration(days: 14),
     http.Client? client,
@@ -34,9 +37,13 @@ class RugReefer {
 
   Future<List<Map<String, dynamic>>> lookup(double latitude, double longitude, {double distanceThreshold = 10.0}) async {
     final String geohash = GeoHasher().encode(latitude, longitude, precision: 4);
-    return kIsWeb 
+    final jsonMap = await loadJsonFromAssets(categoryMap);
+
+    List<Map<String, dynamic>> rawData = kIsWeb 
         ? await _lookupWeb(geohash, latitude, longitude, distanceThreshold)
         : await _lookupFile(geohash, latitude, longitude, distanceThreshold);
+
+    return _processMetadata(rawData, jsonMap, latitude, longitude, distanceThreshold);
   }
 
   Future<List<Map<String, dynamic>>> _lookupFile(String geohash, double latitude, double longitude, double distanceThreshold) async {
@@ -47,7 +54,7 @@ class RugReefer {
       await _updateLastAccessTime(geohash);
     }
     final String geoJsonStr = utf8.decode(GZipCodec().decode(cacheFile.readAsBytesSync()));
-    return _findMetadata(latitude, longitude, jsonDecode(geoJsonStr), distanceThreshold);
+    return jsonDecode(geoJsonStr)['features'];
   }
 
   Future<List<Map<String, dynamic>>> _lookupWeb(String geohash, double latitude, double longitude, double distanceThreshold) async {
@@ -59,12 +66,12 @@ class RugReefer {
         final geoJsonStr = utf8.decode(response.bodyBytes);
         await prefs.setString('geojson_$geohash', geoJsonStr);
         await _updateLastAccessTime(geohash);
-        return _findMetadata(latitude, longitude, jsonDecode(geoJsonStr), distanceThreshold);
+        return jsonDecode(geoJsonStr)['features'];
       }
       throw Exception('Failed to download GeoJSON for geohash: $geohash');
     }
     await _updateLastAccessTime(geohash);
-    return _findMetadata(latitude, longitude, jsonDecode(cachedGeoJson), distanceThreshold);
+    return jsonDecode(cachedGeoJson)['features'];
   }
 
   Future<void> _downloadGeoJson(String geohash, File cacheFile) async {
@@ -102,12 +109,20 @@ class RugReefer {
     }
   }
 
-  List<Map<String, dynamic>> _findMetadata(double latitude, double longitude, Map<String, dynamic> geoJson, double distanceThreshold) {
+  Future<Map<String, dynamic>> loadJsonFromAssets(String assetPath) async {
+    final jsonString = await rootBundle.loadString(assetPath);
+    return jsonDecode(jsonString);
+  }
+
+  List<Map<String, dynamic>> _processMetadata(List<Map<String, dynamic>> features, Map<String, dynamic> jsonMap, double latitude, double longitude, double distanceThreshold) {
     final Position point = Position(longitude, latitude);
-    final List<Map<String, dynamic>> results = [];
-    for (var feature in geoJson['features']) {
+    Map<String, Map<String, List<String>>> groupedObjects = {};
+
+    for (var feature in features) {
       final geometry = feature['geometry'];
       final metadata = Map<String, dynamic>.from(feature['properties']['tags'] ?? {})..removeWhere((_, v) => v == null);
+      String? mainKey;
+
       switch (geometry['type']) {
         case 'Polygon':
           final polygon = Polygon(
@@ -117,7 +132,7 @@ class RugReefer {
                     .toList())
                 .toList(),
           );
-          if (booleanPointInPolygon(point, polygon)) results.add({"type": "polygon", ...metadata});
+          if (booleanPointInPolygon(point, polygon)) mainKey = 'in';
           break;
         case 'LineString':
           final line = LineString(
@@ -125,11 +140,26 @@ class RugReefer {
                 .map((p) => Position(p[0].toDouble(), p[1].toDouble()))
                 .toList(),
           );
-          if (_isPointNearLine(Point(coordinates: point), line, distanceThreshold)) results.add({"type": "line", ...metadata});
+          if (_isPointNearLine(Point(coordinates: point), line, distanceThreshold)) mainKey = 'by';
           break;
       }
+      if (mainKey == null) continue;
+
+      groupedObjects.putIfAbsent(mainKey, () => {});
+      for (var key in metadata.keys) {
+        for (var category in jsonMap.keys) {
+          var categoryMap = jsonMap[category];
+          if (categoryMap is Map && categoryMap.containsKey(key)) {
+            var rule = categoryMap[key];
+            if (rule is String || (rule is List && rule.contains(metadata[key])) || rule == true) {
+              groupedObjects[mainKey]!.putIfAbsent(category, () => []);
+              groupedObjects[mainKey]![category]!.add(metadata[key]);
+            }
+          }
+        }
+      }
     }
-    return results;
+    return groupedObjects.entries.map((entry) => {entry.key: entry.value}).toList();
   }
 
   bool _isPointNearLine(Point point, LineString line, double distanceThreshold) {