Implemented suggested changes.

Fixes #94

Author: Vassyli

src/EventManager.php

@@ -11,7 +11,7 @@
 use LotGD\Core\Exceptions\ClassNotFoundException;
 use LotGD\Core\Exceptions\SubscriptionNotFoundException;
 use LotGD\Core\Exceptions\WrongTypeException;
-use LotGD\Core\Events\EventContextDataContainer;
+use LotGD\Core\Events\EventContextData;
 
 /**
  * Manages a simple publish/subscribe system based on regular expressions
@@ -35,9 +35,10 @@ public function __construct(Game $g)
      * are run.
      *
      * @param string $event The name of the event to publish.
-     * @param EventContextDataContainer $contextData The Data context
+     * @param EventContextData $contextData The Data context
+     * @return EventContextData The changed data.
      */
-    public function publish(string $event, EventContextDataContainer $contextData): EventContextDataContainer
+    public function publish(string $event, EventContextData $contextData): EventContextData
     {
         // For right now, implement the naive approach of iterating every entry
         // in the subscription database, checking the regular expression. We
@@ -56,9 +57,9 @@ public function publish(string $event, EventContextDataContainer $contextData):
                 $eventContext = new EventContext($event, $s->getPattern(), $contextData);
 
                 $returnedEventContext = $class::handleEvent($this->g, $eventContext);
-                if ($returnedEventContext->hasDataChanged($contextData)) {
-                    $contextData = $returnedEventContext->getData();
-                }
+                // Overwrite contextData - contextData might be the same if nothing has changed,
+                // or might reference a completely new object the event handler changed a value.
+                $contextData = $returnedEventContext->getData();
             }
         }
 

src/Events/EventContext.php

@@ -2,7 +2,6 @@
 declare(strict_types=1);
 
 namespace LotGD\Core\Events;
-use LotGD\Core\Exceptions\ArgumentException;
 
 
 /**
@@ -20,12 +19,12 @@ class EventContext
      * EventContext constructor.
      * @param string $event The published event
      * @param string $matchingPattern The matching pattern
-     * @param EventContextDataContainer $data
+     * @param EventContextData $data
      */
     public function __construct(
         string $event,
         string $matchingPattern,
-        EventContextDataContainer $data
+        EventContextData $data
     ) {
         $this->event = $event;
         $this->matchingPattern = $matchingPattern;
@@ -62,9 +61,9 @@ public function hasDataType(string $type): bool
 
     /**
      * Returns the immutable data container.
-     * @return EventContextDataContainer
+     * @return EventContextData
      */
-    public function getData(): EventContextDataContainer
+    public function getData(): EventContextData
     {
         return $this->data;
     }
@@ -100,10 +99,10 @@ public function setDataFields($data)
 
     /**
      * Checks if given original data is the same as currently held within this context.
-     * @param EventContextDataContainer $originalData
+     * @param EventContextData $originalData
      * @return bool
      */
-    public function hasDataChanged(EventContextDataContainer $originalData): bool
+    public function hasDataChanged(EventContextData $originalData): bool
     {
         return $this->data === $originalData ? false : true;
     }

src/Events/EventContextData.php

@@ -3,12 +3,134 @@
 
 namespace LotGD\Core\Events;
 
+use LotGD\Core\Exceptions\ArgumentException;
 
 /**
- * Data container for default, unspecific data without any sanitizing on the given fields.
+ * EventContextDataContainer to provide a basic structure for managing contextual data of an event.
+ *
+ * This class must be immutable and returns always a new instance of itself for any change.
  * @package LotGD\Core\Events
+ * @immutable
  */
-class EventContextData extends EventContextDataContainer
+class EventContextData
 {
+    private $data;
 
+    /**
+     * Creates a new instance of a data container.
+     *
+     * Sub types can change this method to force certain parameters.
+     * @param array $data
+     * @return EventContextData
+     */
+    public static function create(array $data): self
+    {
+        return new static($data);
+    }
+
+    /**
+     * protected constructor..
+     * @see self::create
+     * @param array $data
+     */
+    protected function __construct(array $data)
+    {
+        $this->data = $data;
+    }
+
+    /**
+     * Returns true if container has a certain field.
+     * @param string $field
+     * @return bool
+     */
+    public function has(string $field): bool
+    {
+        return array_key_exists($field, $this->data);
+    }
+
+    /**
+     * Returns the value of a field.
+     * @param string $field
+     * @return mixed
+     */
+    public function get(string $field)
+    {
+        if ($this->has($field)) {
+            return $this->data[$field];
+        } else {
+            $this->throwException($field);
+        }
+    }
+
+    /**
+     * Sets a field to a new value and returns a new data container
+     * @param string $field
+     * @param $value
+     * @return EventContextData
+     */
+    public function set(string $field, $value): self
+    {
+        if ($this->has($field)) {
+            $data = $this->data;
+            $data[$field] = $value;
+
+            return new static($data);
+        } else {
+            $this->throwException($field);
+        }
+    }
+
+    /**
+     * Sets multiple fields at once
+     * @param array $data array of $field=>$value pairs
+     * @return EventContextData
+     */
+    public function setFields(array $data): self
+    {
+        $data = $this->data;
+
+        foreach ($data as $field => $value) {
+            if ($this->has($field)) {
+                $data[$field] = $value;
+            } else {
+                $this->throwException($field);
+            }
+        }
+
+        return new static($data);
+    }
+
+    /**
+     * Returns a list of fields in this context
+     * @return array
+     */
+    private function getListOfFields(): array
+    {
+        return array_keys($this->data);
+    }
+
+    /**
+     * Returns a comma separated string with all allowed fields, for debugging reasons.
+     * @return string
+     */
+    private function getFormattedListOfFields(): string
+    {
+        return substr(
+            implode(", ", $this->getListOfFields()),
+            0,
+            -2
+        );
+    }
+
+    /**
+     * internal use only - throws an ArgumentException a field is given that's not valid.
+     * @param $field
+     * @throws ArgumentException
+     */
+    private function throwException($field)
+    {
+        throw new ArgumentException(
+            "{$field} is not valid in this context, only {$this->getFormattedListOfFields()} are allowed."
+        );
+    }
 }

src/Events/EventContextDataContainer.php

@@ -23,7 +23,7 @@
  *  redirect    Scene|null
  * @package LotGD\Core\Events
  */
-class NavigateToScene extends EventContextDataContainer
+class NavigateToSceneData extends EventContextData
 {
     /**
      * NavigateToScene constructor.

src/Events/NavigateToScene.php src/Events/NavigateToSceneData.phpsrc/Events/NavigateToScene.php renamed to src/Events/NavigateToSceneData.php

@@ -16,7 +16,7 @@
  *  scene       Scene|null
  * @package LotGD\Core\Events
  */
-class NewViewpoint extends EventContextDataContainer
+class NewViewpointData extends EventContextData
 {
     /**
      * NewViewpoint constructor.