From 87c9c991f471b5bd9331fb26f014427750b898ea Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C5=91cze=20Bence?= <bence@pocze.ch>
Date: Sat, 17 Jun 2023 11:53:46 +0200
Subject: [PATCH] implement multi relation loading

---
 src/PersistentData/Model/Model.php           |  2 ++
 src/PersistentData/PersistentDataManager.php | 34 ++++++++++++++++++++
 2 files changed, 36 insertions(+)

diff --git a/src/PersistentData/Model/Model.php b/src/PersistentData/Model/Model.php
index c5f566c..9c100ae 100644
--- a/src/PersistentData/Model/Model.php
+++ b/src/PersistentData/Model/Model.php
@@ -8,6 +8,8 @@ abstract class Model
 
     protected static array $relations = [];
 
+    protected static array $multiRelations = [];
+
     protected $id = null;
 
     private array $snapshot = [];
diff --git a/src/PersistentData/PersistentDataManager.php b/src/PersistentData/PersistentDataManager.php
index 6547782..f0a2569 100644
--- a/src/PersistentData/PersistentDataManager.php
+++ b/src/PersistentData/PersistentDataManager.php
@@ -92,6 +92,40 @@ class PersistentDataManager implements IPersistentDataManager
         }
     }
 
+    public function loadMultiRelationsFromDb(array $models, string $relation, bool $useRelations = false, array $withRelations = []) {
+        if (count($models) === 0) {
+            return;
+        }
+
+        $parentModelType = get_class($models[0]);
+        $relationModelsSetter = 'set' . str_replace('_', '', ucwords($relation, '_'));
+        $relationModelType = $parentModelType::$multiRelations[$relation][0];
+        $reverseRelation = $parentModelType::$multiRelations[$relation][1];
+        $reverseRelationIdGetter = 'get' . str_replace('_', '', ucwords($reverseRelation, '_')) . 'Id';
+
+        $parentModelsById = [];
+        foreach ($models as $model) {
+            $parentModelsById[$model->getId()] = $model;
+        }
+
+        $select = new Select($this->dbConnection);
+        $select->where($reverseRelation . '_id', 'IN', array_keys($parentModelsById));
+
+        $relationsByParentModelId = [];
+        foreach ($this->selectMultipleFromDb($select, $relationModelType, $useRelations, $withRelations) as $relationModel) {
+            $reverseRelationId = $relationModel->$reverseRelationIdGetter();
+            if (!isset($relationsByParentModelId[$reverseRelationId])) {
+                $relationsByParentModelId[$reverseRelationId] = [];
+            }
+            $relationsByParentModelId[$reverseRelationId][] = $relationModel;
+        }
+
+        foreach ($parentModelsById as $parentModelId => $parentModel) {
+            $relationModels = $relationsByParentModelId[$parentModelId] ?? [];
+            $parentModel->$relationModelsSetter($relationModels);
+        }
+    }
+
     public function saveToDb(Model $model): void
     {
         $this->syncRelations($model);