From e7a76b19bcb1accfcc5983fed4b8aea1f57a29e2 Mon Sep 17 00:00:00 2001
From: Timm Preetz <timm@preetz.us>
Date: Mon, 2 Dec 2024 17:05:34 +0100
Subject: [PATCH] Add `delete(where:)`

---
 CHANGELOG.md                        |  1 +
 lib/src/index_entity_store.dart     | 55 +++++++++++++++++++++--
 test/indexed_entity_store_test.dart | 70 +++++++++++++++++++++++++++++
 3 files changed, 122 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 816550a..5486e0f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@
 * Add tests for internal schema migrations
 * Speed up `writeMany` by defaulting to use a single statement for all inserts (as opposed to a single transactions with many individual inserts)
   * One can revert to the previous behavior by setting `singleStatement: false` in the call
+* Add `delete(where: )` to delete all rows matching a specific index-query
 
 ## 2.0.0
 
diff --git a/lib/src/index_entity_store.dart b/lib/src/index_entity_store.dart
index 2e8f858..60baafc 100644
--- a/lib/src/index_entity_store.dart
+++ b/lib/src/index_entity_store.dart
@@ -321,7 +321,7 @@ class IndexedEntityStore<T, K> {
     final Iterable<T>? entities,
     final K? key,
     final Iterable<K>? keys,
-    // TODO(tp): QueryBuilder? where,
+    final QueryBuilder? where,
     final bool? all,
   }) {
     assert(
@@ -329,22 +329,35 @@ class IndexedEntityStore<T, K> {
           entities != null ||
           key != null ||
           keys != null ||
+          where != null ||
           all != null,
     );
     assert(
       all == null ||
-          (entity == null && entities == null && key == null && keys == null),
+          (entity == null &&
+              entities == null &&
+              key == null &&
+              keys == null &&
+              where == null),
     );
 
     if (all == true) {
       _deleteAll();
     } else {
-      _deleteManyByKey({
+      final combinedKeys = {
         if (entity != null) _connector.getPrimaryKey(entity),
         ...?entities?.map(_connector.getPrimaryKey),
         if (key != null) key,
         ...?keys,
-      });
+      };
+
+      if (combinedKeys.isNotEmpty) {
+        _deleteManyByKey(combinedKeys);
+      }
+
+      if (where != null) {
+        _deleteWhere(where);
+      }
     }
   }
 
@@ -386,6 +399,40 @@ class IndexedEntityStore<T, K> {
     _handleUpdate(keys);
   }
 
+  /// Deletes entities matching the query
+  void _deleteWhere(QueryBuilder query) {
+    final Set<K> keys;
+
+    try {
+      _database.execute('BEGIN');
+
+      final whereClause = query(_indexColumns)._entityKeysQuery();
+
+      final result = _database.select(
+        'DELETE FROM `entity` '
+        ' WHERE `type` = ? '
+        ' AND `entity`.`key` IN ( ${whereClause.$1} ) '
+        ' RETURNING `key`',
+        [
+          _entityKey,
+          ...whereClause.$2,
+        ],
+      );
+
+      keys = {
+        for (final row in result) row['key']! as K,
+      };
+
+      _database.execute('COMMIT');
+    } catch (e) {
+      _database.execute('ROLLBACK');
+
+      rethrow;
+    }
+
+    _handleUpdate(keys);
+  }
+
   void _assertNoMoreIndexEntries(K key) {
     assert(
       _database.select(
diff --git a/test/indexed_entity_store_test.dart b/test/indexed_entity_store_test.dart
index b427fef..4d4e781 100644
--- a/test/indexed_entity_store_test.dart
+++ b/test/indexed_entity_store_test.dart
@@ -1173,6 +1173,71 @@ void main() {
     expect(listSubscription.value, isEmpty);
     expect(fooStore.queryOnce(), isEmpty);
   });
+
+  test(
+    'delete(where: )',
+    () async {
+      final path =
+          '/tmp/index_entity_store_test_${FlutterTimeline.now}.sqlite3';
+
+      final db = IndexedEntityDabase.open(path);
+
+      final valueWrappingConnector =
+          IndexedEntityConnector<_ValueWrapper, int, String>(
+        entityKey: 'value_wrapper',
+        getPrimaryKey: (f) => f.key,
+        getIndices: (index) {
+          index((e) => e.value, as: 'value');
+        },
+        serialize: (f) => jsonEncode(f.toJSON()),
+        deserialize: (s) => _ValueWrapper.fromJSON(
+          jsonDecode(s) as Map<String, dynamic>,
+        ),
+      );
+
+      final valueStore = db.entityStore(valueWrappingConnector);
+
+      valueStore.writeMany(
+        [
+          for (var i = 0; i < 10; i++)
+            _ValueWrapper(FlutterTimeline.now + i, '$i'),
+        ],
+        singleStatement: false,
+      );
+
+      final allEntities = valueStore.query();
+      final entityValue2 = valueStore.single(
+        where: (cols) => cols['value'].equals('2'),
+      );
+
+      expect(allEntities.value, hasLength(10));
+      expect(entityValue2.value, isNotNull);
+
+      // no match
+      valueStore.delete(where: (cols) => cols['value'].equals('11'));
+      expect(allEntities.value, hasLength(10));
+      expect(entityValue2.value, isNotNull);
+
+      // no match for complete query
+      valueStore.delete(
+        where: (cols) => cols['value'].equals('11') & cols['value'].equals('2'),
+      );
+      expect(allEntities.value, hasLength(10));
+      expect(entityValue2.value, isNotNull);
+
+      // match delete 2 entries
+      valueStore.delete(
+        where: (cols) => cols['value'].equals('2') | cols['value'].equals('7'),
+      );
+      expect(allEntities.value, hasLength(8));
+      expect(entityValue2.value, isNull);
+
+      allEntities.dispose();
+      entityValue2.dispose();
+
+      expect(valueStore.subscriptionCount, 0);
+    },
+  );
 }
 
 class _FooEntity {
@@ -1399,4 +1464,9 @@ class _ValueWrapper {
       json['value'],
     );
   }
+
+  @override
+  String toString() {
+    return '_ValueWrapper($key, $value)';
+  }
 }