Collection nested queries (#44)

* added collection nested query extension

* fixed save inverse relation bug

* added tests for nested queries

* refactoring

Sources/SwiftletModel/Model/Query.swift

@@ -132,6 +132,57 @@ public extension Query {
     }
 }
 
+public extension Collection {
+    func with<Entity, Child, Directionality, Constraints>(
+        _ keyPath: WritableKeyPath<Entity, ToOneRelation<Child, Directionality, Constraints>>,
+        nested: @escaping QueryModifier<Child> = { $0 }) -> [Query<Entity>] where Element == Query<Entity> {
+
+        map { $0.with(keyPath, nested: nested) }
+    }
+
+    func with<Entity, Child, Directionality, Constraints>(
+        _ keyPath: WritableKeyPath<Entity, ToManyRelation<Child, Directionality, Constraints>>,
+        nested: @escaping QueryModifier<Child> = { $0 }
+
+    ) -> [Query<Entity>] where Element == Query<Entity> {
+
+        map { $0.with(keyPath, nested: nested) }
+    }
+
+    func with<Entity, Child, Directionality, Constraints>(
+        fragment keyPath: WritableKeyPath<Entity, ToManyRelation<Child, Directionality, Constraints>>,
+        nested: @escaping QueryModifier<Child> = { $0 }
+
+    ) -> [Query<Entity>] where Element == Query<Entity> {
+
+        map { $0.with(fragment: keyPath, nested: nested) }
+    }
+
+    func id<Entity, Child, Directionality, Constraints>(
+        _ keyPath: WritableKeyPath<Entity, ToOneRelation<Child, Directionality, Constraints>>
+
+    ) -> [Query<Entity>] where Element == Query<Entity> {
+
+        map { $0.id(keyPath) }
+    }
+
+    func ids<Entity, Child, Directionality, Constraints>(
+        _ keyPath: WritableKeyPath<Entity, ToManyRelation<Child, Directionality, Constraints>>
+
+    ) -> [Query<Entity>] where Element == Query<Entity> {
+
+        map { $0.ids(keyPath) }
+    }
+
+    func ids<Entity, Child, Directionality, Constraints>(
+        fragment keyPath: WritableKeyPath<Entity, ToManyRelation<Child, Directionality, Constraints>>
+
+    ) -> [Query<Entity>] where Element == Query<Entity> {
+
+        map { $0.ids(fragment: keyPath) }
+    }
+}
+
 extension Context {
     func query<Entity: EntityModel>(_ id: Entity.ID) -> Query<Entity> {
         Query(context: self, id: id)

Sources/SwiftletModel/Relation/Relation.swift

@@ -112,7 +112,7 @@ extension Relation {
         }
     }
 
-    var inverseLinkUpdateOption: Option {
+    static var inverseLinkUpdateOption: Option {
         Cardinality.isToMany ? .append : .replace
     }
 }

Sources/SwiftletModel/Relation/RelationSave.swift

@@ -142,7 +142,7 @@ private extension EntityModel {
                     children: [id],
                     attribute: LinkAttribute(
                         name: inverse.name,
-                        updateOption: relation(keyPath).inverseLinkUpdateOption
+                        updateOption: MutualRelation<Self, InverseRelation, InverseConstraint>.inverseLinkUpdateOption
                     )
                 )
             }