feat: make event state constructor-only and immutable

Signed-off-by: Sebastian Krupinski <krupinski01@gmail.com>

shared/lib/Event/Event.php

@@ -10,16 +10,18 @@ namespace KTXF\Event;
 class Event
 {
     private bool $propagationStopped = false;
-    private array $data = [];
-    private float $timestamp;
-    private string $eventId;
-    private ?string $tenantId = null;
-    private ?string $identityId = null;
+    private readonly array $data;
+    private readonly float $timestamp;
+    private readonly string $eventId;
 
     public function __construct(
         private readonly string $name,
-        array $data = []
+        array $data = [],
+        private readonly ?string $tenantId = null,
+        private readonly ?string $identityId = null,
     ) {
+        self::validateData($data);
+
         $this->data = $data;
         $this->timestamp = microtime(true);
         $this->eventId = bin2hex(random_bytes(16));
@@ -41,15 +43,6 @@ class Event
         return $this->data[$key] ?? $default;
     }
 
-    /**
-     * Set a data value
-     */
-    public function set(string $key, mixed $value): self
-    {
-        $this->data[$key] = $value;
-        return $this;
-    }
-
     /**
      * Check if a data key exists
      */
@@ -111,15 +104,6 @@ class Event
         return $this->tenantId;
     }
 
-    /**
-     * Set tenant ID for multi-tenant context
-     */
-    public function setTenantId(?string $tenantId): self
-    {
-        $this->tenantId = $tenantId;
-        return $this;
-    }
-
     /**
      * Get identity ID (user who triggered the event)
      */
@@ -128,12 +112,18 @@ class Event
         return $this->identityId;
     }
 
-    /**
-     * Set identity ID
-     */
-    public function setIdentityId(?string $identityId): self
+    private static function validateData(array $data): void
     {
-        $this->identityId = $identityId;
-        return $this;
+        foreach ($data as $value) {
+            if (is_array($value)) {
+                self::validateData($value);
+                continue;
+            }
+            if ($value !== null && !is_scalar($value)) {
+                throw new \InvalidArgumentException(
+                    'Event data must contain only scalar, null, or array values.',
+                );
+            }
+        }
     }
 }