Add ability to inject step runners

[PREMIUM-180]

mailpoet/lib/Automation/Engine/Control/StepRunner.php

@@ -11,6 +11,7 @@ use MailPoet\Automation\Engine\Storage\WorkflowRunStorage;
 use MailPoet\Automation\Engine\Storage\WorkflowStorage;
 use MailPoet\Automation\Engine\WordPress;
 use MailPoet\Automation\Engine\Workflows\Step;
+use MailPoet\Automation\Engine\Workflows\StepRunner as StepRunnerInterface;
 use MailPoet\Automation\Engine\Workflows\WorkflowRun;
 use Throwable;
 
@@ -30,6 +31,9 @@ class StepRunner {
   /** @var WorkflowStorage */
   private $workflowStorage;
 
+  /** @var array<string, StepRunnerInterface> */
+  private $stepRunners;
+
   public function __construct(
     ActionScheduler $actionScheduler,
     ActionStepRunner $actionStepRunner,
@@ -46,6 +50,12 @@ class StepRunner {
 
   public function initialize(): void {
     $this->wordPress->addAction(Hooks::WORKFLOW_STEP, [$this, 'run']);
+    $this->addStepRunner(Step::TYPE_ACTION, $this->actionStepRunner);
+    $this->wordPress->doAction(Hooks::STEP_RUNNER_INITIALIZE, [$this]);
+  }
+
+  public function addStepRunner(string $stepType, StepRunnerInterface $stepRunner): void {
+    $this->stepRunners[$stepType] = $stepRunner;
   }
 
   /** @param mixed $args */
@@ -98,8 +108,8 @@ class StepRunner {
     }
 
     $stepType = $step->getType();
-    if ($stepType === Step::TYPE_ACTION) {
+    if (isset($this->stepRunners[$stepType])) {
-      $this->actionStepRunner->run($step, $workflow, $workflowRun);
+      $this->stepRunners[$stepType]->run($step, $workflow, $workflowRun);
     } else {
       throw new InvalidStateException();
     }

mailpoet/lib/Automation/Engine/Control/Steps/ActionStepRunner.php

@@ -5,10 +5,11 @@ namespace MailPoet\Automation\Engine\Control\Steps;
 use MailPoet\Automation\Engine\Exceptions\InvalidStateException;
 use MailPoet\Automation\Engine\Registry;
 use MailPoet\Automation\Engine\Workflows\Step;
+use MailPoet\Automation\Engine\Workflows\StepRunner;
 use MailPoet\Automation\Engine\Workflows\Workflow;
 use MailPoet\Automation\Engine\Workflows\WorkflowRun;
 
-class ActionStepRunner {
+class ActionStepRunner implements StepRunner {
   /** @var Registry */
   private $registry;
 

mailpoet/lib/Automation/Engine/Hooks.php

@@ -5,6 +5,7 @@ namespace MailPoet\Automation\Engine;
 class Hooks {
   public const INITIALIZE = 'mailpoet/automation/initialize';
   public const API_INITIALIZE = 'mailpoet/automation/api/initialize';
+  public const STEP_RUNNER_INITIALIZE = 'mailpoet/automation/step_runner/initialize';
   public const TRIGGER = 'mailpoet/automation/trigger';
   public const WORKFLOW_STEP = 'mailpoet/automation/workflow/step';
 }

mailpoet/lib/Automation/Engine/Workflows/Step.php

@@ -16,10 +16,10 @@ class Step {
   private $key;
 
   /** @var string|null */
-  private $nextStepId;
+  protected $nextStepId;
 
   /** @var array */
-  private $args;
+  protected $args;
 
   public function __construct(
     string $id,

mailpoet/lib/Automation/Engine/Workflows/StepRunner.php

@@ -0,0 +1,7 @@
+<?php declare(strict_types = 1);
+
+namespace MailPoet\Automation\Engine\Workflows;
+
+interface StepRunner {
+  public function run(Step $step, Workflow $workflow, WorkflowRun $workflowRun): void;
+}

mailpoet/lib/Automation/Integrations/MailPoet/Subjects/SubscriberSubject.php

@@ -33,7 +33,7 @@ class SubscriberSubject implements Subject {
           return $this->getSubscriber()->getId();
         }
       ),
-      
+
       'email' => new Field(
         'mailpoet:subscriber:email',
         Field::TYPE_STRING,