Merge pull request #50 from flutter-news-app-full-source-code/integrate-name-based-filtering-for-the-country-model

fulleni · web-flow · commit 53e0df1a2bb5 · 2025-08-22T07:57:58.000+01:00
Integrate name based filtering for the country model
diff --git a/lib/src/registry/data_operation_registry.dart b/lib/src/registry/data_operation_registry.dart
@@ -131,9 +131,12 @@ class DataOperationRegistry {
       ),
       'country': (c, uid, f, s, p) async {
         final usage = f?['usage'] as String?;
-        if (usage != null && usage.isNotEmpty) {
-          // For 'country' model with 'usage' filter, delegate to CountryService.
-          // Sorting and pagination are not supported for this specialized query.
+        final name = f?['name'] as String?;
+
+        // If either 'usage' or 'name' filter is present, delegate to CountryService.
+        // Sorting and pagination are handled by CountryService for these specialized queries.
+        if ((usage != null && usage.isNotEmpty) ||
+            (name != null && name.isNotEmpty)) {
           final countryService = c.read<CountryService>();
           final countries = await countryService.getCountries(f);
           return PaginatedResponse<Country>(
@@ -142,13 +145,14 @@ class DataOperationRegistry {
             hasMore: false, // No more items as it's a complete filtered set
           );
         } else {
-          // For standard requests, use the repository which supports pagination/sorting.
+          // For standard requests without specialized filters, use the repository
+          // which supports pagination/sorting.
           return c.read<DataRepository<Country>>().readAll(
-                userId: uid,
-                filter: f,
-                sort: s,
-                pagination: p,
-              );
+            userId: uid,
+            filter: f,
+            sort: s,
+            pagination: p,
+          );
         }
       },
       'language': (c, uid, f, s, p) => c
diff --git a/lib/src/services/country_service.dart b/lib/src/services/country_service.dart
@@ -48,42 +48,60 @@ class CountryService {
   static const Duration _cacheDuration = Duration(hours: 1);
 
   // In-memory caches for frequently accessed lists with time-based invalidation.
-  _CacheEntry<List<Country>>? _cachedEventCountries;
-  _CacheEntry<List<Country>>? _cachedHeadquarterCountries;
+  final Map<String, _CacheEntry<List<Country>>> _cachedEventCountries = {};
+  final Map<String, _CacheEntry<List<Country>>> _cachedHeadquarterCountries =
+      {};
 
   // Futures to hold in-flight aggregation requests to prevent cache stampedes.
-  Future<List<Country>>? _eventCountriesFuture;
-  Future<List<Country>>? _headquarterCountriesFuture;
+  final Map<String, Future<List<Country>>> _eventCountriesFutures = {};
+  final Map<String, Future<List<Country>>> _headquarterCountriesFutures = {};
 
   /// Retrieves a list of countries based on the provided filter.
   ///
   /// Supports filtering by 'usage' to get countries that are either
   /// 'eventCountry' in headlines or 'headquarters' in sources.
-  /// If no specific usage filter is provided, it returns all active countries.
+  /// It also supports filtering by 'name' (full or partial match).
   ///
   /// - [filter]: An optional map containing query parameters.
   ///   Expected keys:
   ///   - `'usage'`: String, can be 'eventCountry' or 'headquarters'.
+  ///   - `'name'`: String, a full or partial country name for search.
   ///
   /// Throws [BadRequestException] if an unsupported usage filter is provided.
   /// Throws [OperationFailedException] for internal errors during data fetch.
   Future<List<Country>> getCountries(Map<String, dynamic>? filter) async {
     _log.info('Fetching countries with filter: $filter');
 
     final usage = filter?['usage'] as String?;
+    final name = filter?['name'] as String?;
+
+    Map<String, dynamic>? nameFilter;
+    if (name != null && name.isNotEmpty) {
+      // Create a case-insensitive regex filter for the name.
+      nameFilter = {r'$regex': name, r'$options': 'i'};
+    }
 
     if (usage == null || usage.isEmpty) {
-      _log.fine('No usage filter provided. Fetching all active countries.');
-      return _getAllCountries();
+      _log.fine(
+        'No usage filter provided. Fetching all active countries '
+        'with nameFilter: $nameFilter.',
+      );
+      return _getAllCountries(nameFilter: nameFilter);
     }
 
     switch (usage) {
       case 'eventCountry':
-        _log.fine('Fetching countries used as event countries in headlines.');
-        return _getEventCountries();
+        _log.fine(
+          'Fetching countries used as event countries in headlines '
+          'with nameFilter: $nameFilter.',
+        );
+        return _getEventCountries(nameFilter: nameFilter);
       case 'headquarters':
-        _log.fine('Fetching countries used as headquarters in sources.');
-        return _getHeadquarterCountries();
+        _log.fine(
+          'Fetching countries used as headquarters in sources '
+          'with nameFilter: $nameFilter.',
+        );
+        return _getHeadquarterCountries(nameFilter: nameFilter);
       default:
         _log.warning('Unsupported country usage filter: "$usage"');
         throw BadRequestException(
@@ -94,15 +112,30 @@ class CountryService {
   }
 
   /// Fetches all active countries from the repository.
-  Future<List<Country>> _getAllCountries() async {
-    _log.finer('Retrieving all active countries from repository.');
+  ///
+  /// - [nameFilter]: An optional map containing a regex filter for the country name.
+  Future<List<Country>> _getAllCountries({
+    Map<String, dynamic>? nameFilter,
+  }) async {
+    _log.finer(
+      'Retrieving all active countries from repository with nameFilter: $nameFilter.',
+    );
     try {
-      final response = await _countryRepository.readAll(
-        filter: {'status': ContentStatus.active.name},
-      );
+      final combinedFilter = <String, dynamic>{
+        'status': ContentStatus.active.name,
+      };
+      if (nameFilter != null && nameFilter.isNotEmpty) {
+        combinedFilter.addAll({'name': nameFilter});
+      }
+
+      final response = await _countryRepository.readAll(filter: combinedFilter);
       return response.items;
     } catch (e, s) {
-      _log.severe('Failed to fetch all countries.', e, s);
+      _log.severe(
+        'Failed to fetch all countries with nameFilter: $nameFilter.',
+        e,
+        s,
+      );
       throw OperationFailedException('Failed to retrieve all countries: $e');
     }
   }
@@ -112,56 +145,84 @@ class CountryService {
   ///
   /// Uses MongoDB aggregation to efficiently get distinct country IDs
   /// and then fetches the full Country objects. Results are cached.
-  Future<List<Country>> _getEventCountries() async {
-    if (_cachedEventCountries != null && _cachedEventCountries!.isValid()) {
-      _log.finer('Returning cached event countries.');
-      return _cachedEventCountries!.data;
+  ///
+  /// - [nameFilter]: An optional map containing a regex filter for the country name.
+  Future<List<Country>> _getEventCountries({
+    Map<String, dynamic>? nameFilter,
+  }) async {
+    final cacheKey = 'eventCountry_${nameFilter ?? 'noFilter'}';
+    if (_cachedEventCountries.containsKey(cacheKey) &&
+        _cachedEventCountries[cacheKey]!.isValid()) {
+      _log.finer('Returning cached event countries for key: $cacheKey.');
+      return _cachedEventCountries[cacheKey]!.data;
+    }
+    // Atomically retrieve or create the future for the specific cache key.
+    var future = _eventCountriesFutures[cacheKey];
+    if (future == null) {
+      future = _fetchAndCacheEventCountries(
+        nameFilter: nameFilter,
+      ).whenComplete(() => _eventCountriesFutures.remove(cacheKey));
+      _eventCountriesFutures[cacheKey] = future;
     }
-    // Atomically assign the future if no fetch is in progress,
-    // and clear it when the future completes.
-    _eventCountriesFuture ??= _fetchAndCacheEventCountries()
-        .whenComplete(() => _eventCountriesFuture = null);
-    return _eventCountriesFuture!;
+    return future;
   }
 
   /// Fetches a distinct list of countries that are referenced as
   /// `headquarters` in sources.
   ///
   /// Uses MongoDB aggregation to efficiently get distinct country IDs
   /// and then fetches the full Country objects. Results are cached.
-  Future<List<Country>> _getHeadquarterCountries() async {
-    if (_cachedHeadquarterCountries != null &&
-        _cachedHeadquarterCountries!.isValid()) {
-      _log.finer('Returning cached headquarter countries.');
-      return _cachedHeadquarterCountries!.data;
+  ///
+  /// - [nameFilter]: An optional map containing a regex filter for the country name.
+  Future<List<Country>> _getHeadquarterCountries({
+    Map<String, dynamic>? nameFilter,
+  }) async {
+    final cacheKey = 'headquarters_${nameFilter ?? 'noFilter'}';
+    if (_cachedHeadquarterCountries.containsKey(cacheKey) &&
+        _cachedHeadquarterCountries[cacheKey]!.isValid()) {
+      _log.finer('Returning cached headquarter countries for key: $cacheKey.');
+      return _cachedHeadquarterCountries[cacheKey]!.data;
     }
-    // Atomically assign the future if no fetch is in progress,
-    // and clear it when the future completes.
-    _headquarterCountriesFuture ??= _fetchAndCacheHeadquarterCountries()
-        .whenComplete(() => _headquarterCountriesFuture = null);
-    return _headquarterCountriesFuture!;
+    // Atomically retrieve or create the future for the specific cache key.
+    var future = _headquarterCountriesFutures[cacheKey];
+    if (future == null) {
+      future = _fetchAndCacheHeadquarterCountries(
+        nameFilter: nameFilter,
+      ).whenComplete(() => _headquarterCountriesFutures.remove(cacheKey));
+      _headquarterCountriesFutures[cacheKey] = future;
+    }
+    return future;
   }
 
   /// Helper method to fetch and cache distinct event countries.
-  Future<List<Country>> _fetchAndCacheEventCountries() async {
-    _log.finer('Fetching distinct event countries via aggregation.');
+  ///
+  /// - [nameFilter]: An optional map containing a regex filter for the country name.
+  Future<List<Country>> _fetchAndCacheEventCountries({
+    Map<String, dynamic>? nameFilter,
+  }) async {
+    _log.finer(
+      'Fetching distinct event countries via aggregation with nameFilter: $nameFilter.',
+    );
     try {
       final distinctCountries = await _getDistinctCountriesFromAggregation(
         repository: _headlineRepository,
         fieldName: 'eventCountry',
+        nameFilter: nameFilter,
       );
-      _cachedEventCountries = _CacheEntry(
+      final cacheKey = 'eventCountry_${nameFilter ?? 'noFilter'}';
+      _cachedEventCountries[cacheKey] = _CacheEntry(
         distinctCountries,
         DateTime.now().add(_cacheDuration),
       );
       _log.info(
         'Successfully fetched and cached ${distinctCountries.length} '
-        'event countries.',
+        'event countries for key: $cacheKey.',
       );
       return distinctCountries;
     } catch (e, s) {
       _log.severe(
-        'Failed to fetch distinct event countries via aggregation.',
+        'Failed to fetch distinct event countries via aggregation '
+        'with nameFilter: $nameFilter.',
         e,
         s,
       );
@@ -170,25 +231,34 @@ class CountryService {
   }
 
   /// Helper method to fetch and cache distinct headquarter countries.
-  Future<List<Country>> _fetchAndCacheHeadquarterCountries() async {
-    _log.finer('Fetching distinct headquarter countries via aggregation.');
+  ///
+  /// - [nameFilter]: An optional map containing a regex filter for the country name.
+  Future<List<Country>> _fetchAndCacheHeadquarterCountries({
+    Map<String, dynamic>? nameFilter,
+  }) async {
+    _log.finer(
+      'Fetching distinct headquarter countries via aggregation with nameFilter: $nameFilter.',
+    );
     try {
       final distinctCountries = await _getDistinctCountriesFromAggregation(
         repository: _sourceRepository,
         fieldName: 'headquarters',
+        nameFilter: nameFilter,
       );
-      _cachedHeadquarterCountries = _CacheEntry(
+      final cacheKey = 'headquarters_${nameFilter ?? 'noFilter'}';
+      _cachedHeadquarterCountries[cacheKey] = _CacheEntry(
         distinctCountries,
         DateTime.now().add(_cacheDuration),
       );
       _log.info(
         'Successfully fetched and cached ${distinctCountries.length} '
-        'headquarter countries.',
+        'headquarter countries for key: $cacheKey.',
       );
       return distinctCountries;
     } catch (e, s) {
       _log.severe(
-        'Failed to fetch distinct headquarter countries via aggregation.',
+        'Failed to fetch distinct headquarter countries via aggregation '
+        'with nameFilter: $nameFilter.',
         e,
         s,
       );
@@ -202,29 +272,40 @@ class CountryService {
   /// - [repository]: The [DataRepository] to perform the aggregation on.
   /// - [fieldName]: The name of the field within the documents that contains
   ///   the country object (e.g., 'eventCountry', 'headquarters').
+  /// - [nameFilter]: An optional map containing a regex filter for the country name.
   ///
   /// Throws [OperationFailedException] for internal errors during data fetch.
-  Future<List<Country>> _getDistinctCountriesFromAggregation<T extends FeedItem>({
+  Future<List<Country>>
+  _getDistinctCountriesFromAggregation<T extends FeedItem>({
     required DataRepository<T> repository,
     required String fieldName,
+    Map<String, dynamic>? nameFilter,
   }) async {
-    _log.finer('Fetching distinct countries for field "$fieldName" via aggregation.');
+    _log.finer(
+      'Fetching distinct countries for field "$fieldName" via aggregation '
+      'with nameFilter: $nameFilter.',
+    );
     try {
-      final pipeline = [
-        {
-          r'$match': {
-            'status': ContentStatus.active.name,
-            '$fieldName.id': {r'$exists': true},
-          },
-        },
-        {
-          r'$group': {
+      final matchStage = <String, Object>{
+        'status': ContentStatus.active.name,
+        '$fieldName.id': <String, Object>{r'$exists': true},
+      };
+
+      // Add name filter if provided
+      if (nameFilter != null && nameFilter.isNotEmpty) {
+        matchStage['$fieldName.name'] = nameFilter;
+      }
+
+      final pipeline = <Map<String, Object>>[
+        <String, Object>{r'$match': matchStage},
+        <String, Object>{
+          r'$group': <String, Object>{
             '_id': '\$$fieldName.id',
-            'country': {r'$first': '\$$fieldName'},
+            'country': <String, Object>{r'$first': '\$$fieldName'},
           },
         },
-        {
-          r'$replaceRoot': {'newRoot': r'$country'},
+        <String, Object>{
+          r'$replaceRoot': <String, Object>{'newRoot': r'$country'},
         },
       ];
 
@@ -238,12 +319,13 @@ class CountryService {
 
       _log.info(
         'Successfully fetched ${distinctCountries.length} distinct countries '
-        'for field "$fieldName".',
+        'for field "$fieldName" with nameFilter: $nameFilter.',
       );
       return distinctCountries;
     } catch (e, s) {
       _log.severe(
-        'Failed to fetch distinct countries for field "$fieldName".',
+        'Failed to fetch distinct countries for field "$fieldName" '
+        'with nameFilter: $nameFilter.',
         e,
         s,
       );
diff --git a/lib/src/services/database_seeding_service.dart b/lib/src/services/database_seeding_service.dart
@@ -118,6 +118,11 @@ class DatabaseSeedingService {
           .collection('sources')
           .createIndex(keys: {'name': 'text'}, name: 'sources_text_index');
 
+      // Index for searching countries by name (case-insensitive friendly)
+      await _db
+          .collection('countries')
+          .createIndex(keys: {'name': 1}, name: 'countries_name_index');
+
       // Indexes for country aggregation queries
       await _db
           .collection('headlines')
