Add collection grid source type processor

Add collection specific source type processor to allow joining fields
before the available grid columns are extracted.

Fixes issue hyva-themes#45.

Api/HyvaGridCollectionProcessorInterface.php

@@ -0,0 +1,23 @@
+<?php declare(strict_types=1);
+
+namespace Hyva\Admin\Api;
+
+use Magento\Framework\Data\Collection\AbstractDb as AbstractDbCollection;
+
+/**
+ * Collection grid source type specific processor interface.
+ */
+interface HyvaGridCollectionProcessorInterface extends HyvaGridSourceProcessorInterface
+{
+    /**
+     * This interface provides an afterInitSelect() callback that is only applicable to collection grid sources.
+     *
+     * This callback is triggered every time the collection grid source is instantiated, before the search
+     * criteria is applied. It is intended to allow joining additional fields that will then be available
+     * as grid columns.
+     *
+     * @param AbstractDbCollection $source
+     * @param string $gridName
+     */
+    public function afterInitSelect(AbstractDbCollection $source, string $gridName): void;
+}

Api/HyvaGridSourceProcessorInterface.php

@@ -40,7 +40,7 @@ public function beforeLoad($source, SearchCriteriaInterface $searchCriteria, str
      * The method must return the new result or null. The $result type depends on the grid configuration.
      * If null is returned, the result value from before afterLoad is used.
      *
-     * Do not mutate $searchCriteria since that will cause multiple loads (because )it's signature change,
+     * Do not mutate $searchCriteria since that will cause multiple loads (because its signature changes,
      * see note on beforeLoad above).
      *
      * @param mixed $rawResult

Model/GridSourceType/CollectionGridSourceType.php

@@ -9,6 +9,7 @@
 use function array_unique as unique;
 use function array_values as values;
 
+use Hyva\Admin\Api\HyvaGridCollectionProcessorInterface;
 use Hyva\Admin\Api\HyvaGridSourceProcessorInterface;
 use Hyva\Admin\Model\GridSourceType\CollectionSourceType\GridSourceCollectionFactory;
 use Hyva\Admin\Model\GridTypeReflection;
@@ -211,7 +212,15 @@ public function extractTotalRowCount(RawGridSourceContainer $rawGridData): int
 
     private function getCollectionInstance(): AbstractDb
     {
-        return $this->gridSourceCollectionFactory->create($this->getCollectionConfig());
+        return reduce(
+            $this->processors,
+            function (AbstractDb $collection, HyvaGridSourceProcessorInterface $processor): AbstractDb {
+                if ($processor instanceof HyvaGridCollectionProcessorInterface) {
+                    $processor->afterInitSelect($collection, $this->gridName);
+                }
+                return $collection;
+            },
+            $this->gridSourceCollectionFactory->create($this->getCollectionConfig()));
     }
 
     private function isTypeReflectionField(string $key): bool

Test/Integration/Model/GridSourceType/CollectionGridSourceTypeTest.php

@@ -2,18 +2,22 @@
 
 namespace Hyva\Admin\Test\Integration\Model\GridSourceType;
 
+use Hyva\Admin\Api\HyvaGridCollectionProcessorInterface;
 use Hyva\Admin\Api\HyvaGridSourceProcessorInterface;
 use Hyva\Admin\Model\DataType\ArrayDataType;
 use Hyva\Admin\Model\DataType\BooleanDataType;
 use Hyva\Admin\Model\DataType\IntDataType;
 use Hyva\Admin\Model\DataType\TextDataType;
+use Hyva\Admin\Model\GridSource\AbstractGridSourceProcessor;
 use Hyva\Admin\Model\GridSourceType\CollectionGridSourceType;
 use Magento\Catalog\Model\Product;
 use Magento\Catalog\Model\ResourceModel\Product\Collection as ProductCollection;
 use Magento\Cms\Model\ResourceModel\Page\Collection as CmsPageCollection;
 use Magento\Framework\Api\SearchCriteria;
 use Magento\Framework\Api\SearchCriteriaInterface;
 use Magento\Framework\App\ResourceConnection;
+use Magento\Framework\Data\Collection\AbstractDb as AbstractDbCollection;
+use Magento\Framework\DB\Select;
 use Magento\Sales\Model\ResourceModel\Order\Collection as OrderCollection;
 use Magento\Sales\Model\ResourceModel\Order\Grid\Collection as OrderGridCollection;
 use Magento\Sales\Setup\SalesSetup;
@@ -288,4 +292,41 @@ public function afterLoad($rawResult, SearchCriteriaInterface $searchCriteria, s
         $records = $sut->extractRecords($rawGridData);
         $this->assertCount(1, $records);
     }
+
+    /**
+     * @magentoDataFixture Magento/Catalog/_files/product_simple.php
+     * @magentoDataFixture Magento/Catalog/_files/products_list.php
+     */
+    public function testAfterInitSelectProcessorCanJoinFieldsForGrid(): void
+    {
+        $processor = new class() extends AbstractGridSourceProcessor implements HyvaGridCollectionProcessorInterface {
+
+            public function afterInitSelect(AbstractDbCollection $source, string $gridName): void
+            {
+                $select = $source->getSelect();
+                // add select expression
+                $select->columns(['foo' => new \Zend_Db_Expr('foo')]);
+                // add field from joined table
+                $source->getSelect()->joinLeft(
+                    'catalog_category_product',
+                    'e.entity_id = catalog_category_product.product_id',
+                    ['test_field' => 'catalog_category_product.entity_id']
+                );
+            }
+        };
+
+        $args = [
+            'gridName'            => 'test',
+            'processors'          => [$processor],
+            'sourceConfiguration' => ['collection' => ProductCollection::class],
+        ];
+        /** @var CollectionGridSourceType $sut */
+        $sut = ObjectManager::getInstance()->create(CollectionGridSourceType::class, $args);
+
+        $columnKeys = $sut->getColumnKeys();
+        $this->assertContains('foo', $columnKeys); // select expression
+        $this->assertContains('test_field', $columnKeys); // joined field
+        $this->assertContains('sku', $columnKeys); // entity table attribute
+        $this->assertContains('color', $columnKeys); // eav attribute
+    }
 }