feat: schema-builder and resolver-builder can handle relations (#2398)

* feat: wip add relation

* feat: add relation for custom and standards objects

* fix: use enum instead of magic string

* fix: remove dead code & fix tests

* fix: typo

* fix: BooleanFilter is missing

* fix: Malformed result error

server/src/tenant/utils/__tests__/deduce-relation-direction.spec.ts

@@ -0,0 +1,69 @@
+import { RelationMetadataInterface } from 'src/tenant/schema-builder/interfaces/relation-metadata.interface';
+
+import { RelationMetadataType } from 'src/metadata/relation-metadata/relation-metadata.entity';
+import {
+  deduceRelationDirection,
+  RelationDirection,
+} from 'src/tenant/utils/deduce-relation-direction.util';
+
+describe('deduceRelationDirection', () => {
+  it('should return FROM when the current object ID matches fromObjectMetadataId', () => {
+    const currentObjectId = 'from_object_id';
+    const relationMetadata = {
+      id: 'relation_id',
+      fromObjectMetadataId: currentObjectId,
+      toObjectMetadataId: 'to_object_id',
+      fromFieldMetadataId: 'from_field_id',
+      toFieldMetadataId: 'to_field_id',
+      relationType: RelationMetadataType.ONE_TO_ONE,
+    };
+
+    const result = deduceRelationDirection(
+      currentObjectId,
+      relationMetadata as RelationMetadataInterface,
+    );
+
+    expect(result).toBe(RelationDirection.FROM);
+  });
+
+  it('should return TO when the current object ID matches toObjectMetadataId', () => {
+    // Arrange
+    const currentObjectId = 'to_object_id';
+    const relationMetadata = {
+      id: 'relation_id',
+      fromObjectMetadataId: 'from_object_id',
+      toObjectMetadataId: currentObjectId,
+      fromFieldMetadataId: 'from_field_id',
+      toFieldMetadataId: 'to_field_id',
+      relationType: RelationMetadataType.ONE_TO_ONE,
+    };
+
+    const result = deduceRelationDirection(
+      currentObjectId,
+      relationMetadata as RelationMetadataInterface,
+    );
+
+    expect(result).toBe(RelationDirection.TO);
+  });
+
+  it('should throw an error when the current object ID does not match any object metadata ID', () => {
+    const currentObjectId = 'unrelated_object_id';
+    const relationMetadata = {
+      id: 'relation_id',
+      fromObjectMetadataId: 'from_object_id',
+      toObjectMetadataId: 'to_object_id',
+      fromFieldMetadataId: 'from_field_id',
+      toFieldMetadataId: 'to_field_id',
+      relationType: RelationMetadataType.ONE_TO_ONE,
+    };
+
+    expect(() =>
+      deduceRelationDirection(
+        currentObjectId,
+        relationMetadata as RelationMetadataInterface,
+      ),
+    ).toThrow(
+      `Relation metadata ${relationMetadata.id} is not related to object ${currentObjectId}`,
+    );
+  });
+});