Add workflow step arg schema validation

[MAILPOET-4629]

mailpoet/lib/Automation/Engine/Validation/WorkflowStepsValidator.php

@@ -0,0 +1,61 @@
+<?php declare(strict_types = 1);
+
+namespace MailPoet\Automation\Engine\Validation;
+
+use MailPoet\Automation\Engine\Data\Step;
+use MailPoet\Automation\Engine\Data\Workflow;
+use MailPoet\Automation\Engine\Exceptions;
+use MailPoet\Automation\Engine\Registry;
+use MailPoet\Automation\Engine\Storage\WorkflowStorage;
+use MailPoet\Validator\Validator;
+
+class WorkflowStepsValidator {
+  /** @var Registry */
+  private $registry;
+
+  /** @var Validator */
+  private $validator;
+
+  /** @var WorkflowStorage */
+  private $workflowStorage;
+
+  /** @var Workflow|null|false */
+  private $cachedExistingWorkflow = false;
+
+  public function __construct(
+    Registry $registry,
+    Validator $validator,
+    WorkflowStorage $workflowStorage
+  ) {
+    $this->validator = $validator;
+    $this->registry = $registry;
+    $this->workflowStorage = $workflowStorage;
+  }
+
+  public function validateSteps(Workflow $workflow): void {
+    foreach ($workflow->getSteps() as $step) {
+      $this->validateStep($workflow, $step);
+    }
+  }
+
+  private function validateStep(Workflow $workflow, Step $step): void {
+    $registryStep = $this->registry->getStep($step->getKey());
+    if ($registryStep) {
+      $this->validator->validate($registryStep->getArgsSchema(), $step->getArgs());
+    } else {
+      // step not registered (e.g. plugin was deactivated) - allow saving it only if it hasn't changed
+      $currentWorkflow = $this->getCurrentWorkflow($workflow->getId());
+      $currentStep = $currentWorkflow ? ($currentWorkflow->getSteps()[$step->getId()] ?? null) : null;
+      if (!$currentStep || $step->toArray() !== $currentStep->toArray()) {
+        throw Exceptions::workflowStepModifiedWhenUnknown($step);
+      }
+    }
+  }
+
+  private function getCurrentWorkflow(int $id): ?Workflow {
+    if ($this->cachedExistingWorkflow === false) {
+      $this->cachedExistingWorkflow = $this->workflowStorage->getWorkflow($id);
+    }
+    return $this->cachedExistingWorkflow;
+  }
+}