Merge pull request 'TIST-36: Prefetch related models for a list of model instances' (#31) from TIST-36 into develop

Reviewed-on: #31
Reviewed-by: greendavid004 <davidkatrinka1995@gmail.com>

functions.php

@@ -252,4 +252,54 @@ function send_email(string $subject, string $body, string $altBody, string $to_a
 
     $mail->send();
 }
-?>
+
+/**
+ * Collects related objects for each origin object based on a given foreign key.
+ *
+ * Returns an array in the following format:
+ * [
+ *     [
+ *         'origin' => $object,        // the origin object
+ *         'relations' => $objects     // related objects from the target model
+ *     ],
+ *     ...
+ * ]
+ *
+ * @param array $objects Array of origin objects (their IDs will be used for matching)
+ * @param string $model_name_format Target model name in "app:model" format to fetch related objects from
+ * @param string $field_key Foreign key in the related model that refers to the origin object ID
+ * @return array An array of relation mappings between origin and related objects
+ */
+function prefetch_related(array $objects, string $model_name_format, string $field_key)
+{
+    [$app, $model] = explode(':', $model_name_format);
+    $model_name = "Lycoreco\Apps\\" . $app . "\Models\\" . $model;
+
+    if (!class_exists($model_name)) {
+        throw new InvalidArgumentException("Model class $model_name does not exist.");
+    }
+
+    $keys = $keys = array_map(fn($obj) => $obj->get_id(), $objects);
+
+    if (empty($keys))
+        return [];
+
+    $related_objects = $model_name::filter(array(
+        [
+            'name'      => 'obj.' . $field_key,
+            'type'      => 'IN',
+            'value'     => $keys
+        ]
+    ));
+
+    return array_map(function ($object) use ($related_objects, $field_key) {
+        $rels = array_filter($related_objects, function ($rel) use ($object, $field_key) {
+            return $rel->{'field_' . $field_key} == $object->get_id();
+        });
+
+        return [
+            'origin' => $object,
+            'relations' => array_values($rels)
+        ];
+    }, $objects);
+}