From a3797b976a5ab6e81924b98e08c8a7840cddb78e Mon Sep 17 00:00:00 2001
From: Jan Jakes <jan.jakes@automattic.com>
Date: Wed, 14 Sep 2022 15:12:25 +0200
Subject: [PATCH] Add triggers under root rule for workflow validation

[MAILPOET-4629]
---
 .../WorkflowRules/TriggersUnderRootRule.php   | 40 +++++++++++++++++++
 .../TriggersUnderRootRuleTest.php             | 34 ++++++++++++++++
 2 files changed, 74 insertions(+)
 create mode 100644 mailpoet/lib/Automation/Engine/Validation/WorkflowRules/TriggersUnderRootRule.php
 create mode 100644 mailpoet/tests/unit/Automation/Engine/Validation/WorkflowRules/TriggersUnderRootRuleTest.php

diff --git a/mailpoet/lib/Automation/Engine/Validation/WorkflowRules/TriggersUnderRootRule.php b/mailpoet/lib/Automation/Engine/Validation/WorkflowRules/TriggersUnderRootRule.php
new file mode 100644
index 0000000000..711766d710
--- /dev/null
+++ b/mailpoet/lib/Automation/Engine/Validation/WorkflowRules/TriggersUnderRootRule.php
@@ -0,0 +1,40 @@
+<?php declare(strict_types = 1);
+
+namespace MailPoet\Automation\Engine\Validation\WorkflowRules;
+
+use MailPoet\Automation\Engine\Data\Step;
+use MailPoet\Automation\Engine\Data\Workflow;
+use MailPoet\Automation\Engine\Exceptions;
+use MailPoet\Automation\Engine\Validation\WorkflowGraph\WorkflowNode;
+use MailPoet\Automation\Engine\Validation\WorkflowGraph\WorkflowNodeVisitor;
+
+class TriggersUnderRootRule implements WorkflowNodeVisitor {
+  /** @var array<string, Step> $triggersMap */
+  private $triggersMap = [];
+
+  public function initialize(Workflow $workflow): void {
+    $this->triggersMap = [];
+    foreach ($workflow->getSteps() as $step) {
+      if ($step->getType() === 'trigger') {
+        $this->triggersMap[$step->getId()] = $step;
+      }
+    }
+  }
+
+  public function visitNode(Workflow $workflow, WorkflowNode $node): void {
+    $step = $node->getStep();
+    if ($step->getType() === Step::TYPE_ROOT) {
+      return;
+    }
+
+    foreach ($step->getNextSteps() as $nextStep) {
+      $nextStepId = $nextStep->getId();
+      if (isset($this->triggersMap[$nextStepId])) {
+        throw Exceptions::workflowStructureNotValid(__('Trigger must be a direct descendant of workflow root', 'mailpoet'));
+      }
+    }
+  }
+
+  public function complete(Workflow $workflow): void {
+  }
+}
diff --git a/mailpoet/tests/unit/Automation/Engine/Validation/WorkflowRules/TriggersUnderRootRuleTest.php b/mailpoet/tests/unit/Automation/Engine/Validation/WorkflowRules/TriggersUnderRootRuleTest.php
new file mode 100644
index 0000000000..467255d018
--- /dev/null
+++ b/mailpoet/tests/unit/Automation/Engine/Validation/WorkflowRules/TriggersUnderRootRuleTest.php
@@ -0,0 +1,34 @@
+<?php declare(strict_types = 1);
+
+namespace MailPoet\Automation\Engine\Validation\WorkflowRules;
+
+require_once __DIR__ . '/WorkflowRuleTest.php';
+
+use MailPoet\Automation\Engine\Data\Step;
+use MailPoet\Automation\Engine\Data\Workflow;
+use MailPoet\Automation\Engine\Exceptions\UnexpectedValueException;
+use MailPoet\Automation\Engine\Validation\WorkflowGraph\WorkflowWalker;
+
+class TriggersUnderRootRuleTest extends WorkflowRuleTest {
+  public function testItDetectsTriggersNotUnderRoot(): void {
+    $workflow = $this->make(Workflow::class, ['getSteps' => [
+      'root' => $this->createStep('root', Step::TYPE_ROOT, ['t', 'a']),
+      'a' => $this->createStep('a', Step::TYPE_ACTION, ['t']),
+      't' => $this->createStep('t', Step::TYPE_TRIGGER, []),
+    ]]);
+
+    $this->expectException(UnexpectedValueException::class);
+    $this->expectExceptionMessage('Invalid workflow structure: Trigger must be a direct descendant of workflow root');
+    (new WorkflowWalker())->walk($workflow, [new TriggersUnderRootRule()]);
+  }
+
+  public function testItPassesWithTriggersUnderRoot(): void {
+    $workflow = $this->make(Workflow::class, ['getSteps' => [
+      'root' => $this->createStep('root', Step::TYPE_ROOT, ['t']),
+      't' => $this->createStep('t', Step::TYPE_TRIGGER, []),
+    ]]);
+
+    (new WorkflowWalker())->walk($workflow, [new TriggersUnderRootRule()]);
+    // no exception thrown
+  }
+}