Add workflow step data definition

[MAILPOET-4136]

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

@@ -5,4 +5,63 @@ namespace MailPoet\Automation\Engine\Workflows;
 class Step {
   public const TYPE_TRIGGER = 'trigger';
   public const TYPE_ACTION = 'action';
+
+  /** @var string */
+  private $id;
+
+  /** @var string */
+  private $type;
+
+  /** @var string */
+  private $key;
+
+  /** @var string|null */
+  private $nextStepId;
+
+  /** @var array */
+  private $args;
+
+  public function __construct(
+    string $id,
+    string $type,
+    string $key,
+    ?string $nextStepId,
+    array $args = []
+  ) {
+    $this->id = $id;
+    $this->type = $type;
+    $this->key = $key;
+    $this->nextStepId = $nextStepId;
+    $this->args = $args;
+  }
+
+  public function getId(): string {
+    return $this->id;
+  }
+
+  public function getType(): string {
+    return $this->type;
+  }
+
+  public function getKey(): string {
+    return $this->key;
+  }
+
+  public function getNextStepId(): ?string {
+    return $this->nextStepId;
+  }
+
+  public function getArgs(): array {
+    return $this->args;
+  }
+
+  public function toArray(): array {
+    return [
+      'id' => $this->id,
+      'type' => $this->type,
+      'key' => $this->key,
+      'next_step_id' => $this->nextStepId,
+      'args' => $this->args,
+    ];
+  }
 }