NEW: Workflow support (#43)

* Handle non-existent record in elemental page save handler

* NEW: Workflow support

_config/workflow.yml

@@ -0,0 +1,22 @@
+---
+Name: 'snapshots-workflow'
+Only:
+  moduleexists: 'symbiote/silverstripe-advancedworkflow'
+---
+Symbiote\AdvancedWorkflow\Actions\PublishItemWorkflowAction:
+  extensions:
+    - SilverStripe\Snapshots\Workflow\WorkflowExtension
+Symbiote\AdvancedWorkflow\Jobs\WorkflowPublishTargetJob:
+   extensions:
+     - SilverStripe\Snapshots\Workflow\WorkflowExtension
+
+SilverStripe\Core\Injector\Injector:
+  SilverStripe\EventDispatcher\Dispatch\Dispatcher:
+    properties:
+      handlers:
+        unpublish:
+          on: [ 'workflowComplete.unpublish' ]
+          handler: '%$SilverStripe\Snapshots\Handler\Form\UnpublishHandler'
+        publish:
+          on: [ 'workflowComplete.publish' ]
+          handler: '%$SilverStripe\Snapshots\Handler\Form\PublishHandler'

src/Handler/Elemental/PageSaveHandler.php

@@ -32,6 +32,9 @@ protected function createSnapshot(EventContextInterface $context): ?Snapshot
         }
 
         $record = $this->getRecordFromContext($context);
+        if (!$record) {
+            return null;
+        }
         if (!$record->hasExtension(ElementalAreasExtension::class)) {
             return parent::createSnapshot($context);
         }

src/Workflow/WorkflowExtension.php

@@ -0,0 +1,29 @@
+<?php
+
+
+namespace SilverStripe\Snapshots\Workflow;
+
+use SilverStripe\EventDispatcher\Dispatch\Dispatcher;
+use SilverStripe\EventDispatcher\Symfony\Event;
+use SilverStripe\ORM\DataExtension;
+use SilverStripe\ORM\DataObject;
+
+class WorkflowExtension extends DataExtension
+{
+    public function onAfterWorkflowPublish(DataObject $target)
+    {
+        $record = DataObject::get_by_id(get_class($target), $target->ID, false);
+        Dispatcher::singleton()->trigger('workflowComplete', new Event('publish', [
+            'record' => $record,
+        ]));
+    }
+
+    public function onAfterWorkflowUnpublish(DataObject $target)
+    {
+        $record = DataObject::get_by_id(get_class($target), $target->ID, false);
+        Dispatcher::singleton()->trigger('workflowComplete', new Event('publish', [
+            'record' => $record,
+        ]));
+    }
+
+}