1 files changed, 124 insertions, 0 deletions
diff --git a/core/event.php b/core/event.php
new file mode 100644
index 00000000..7addb41d
--- /dev/null
+++ b/core/event.php
@@ -0,0 +1,124 @@
+<?php
+
+namespace Core;
+
+/**
+ * Event listener interface
+ *
+ * @package core
+ * @author  Frederic Guillot
+ */
+interface Listener {
+    public function execute(array $data);
+}
+
+/**
+ * Event dispatcher class
+ *
+ * @package core
+ * @author  Frederic Guillot
+ */
+class Event
+{
+    /**
+     * Contains all listeners
+     *
+     * @access private
+     * @var array
+     */
+    private $listeners = array();
+
+    /**
+     * The last triggered event
+     *
+     * @access private
+     * @var string
+     */
+    private $lastEvent = '';
+
+    /**
+     * Triggered events list
+     *
+     * @access private
+     * @var array
+     */
+    private $events = array();
+
+    /**
+     * Attach a listener object to an event
+     *
+     * @access public
+     * @param  string   $eventName   Event name
+     * @param  Listener $listener    Object that implements the Listener interface
+     */
+    public function attach($eventName, Listener $listener)
+    {
+        if (! isset($this->listeners[$eventName])) {
+            $this->listeners[$eventName] = array();
+        }
+
+        $this->listeners[$eventName][] = $listener;
+    }
+
+    /**
+     * Trigger an event
+     *
+     * @access public
+     * @param  string   $eventName   Event name
+     * @param  array    $data        Event data
+     */
+    public function trigger($eventName, array $data)
+    {
+        $this->lastEvent = $eventName;
+        $this->events[] = $eventName;
+
+        if (isset($this->listeners[$eventName])) {
+            foreach ($this->listeners[$eventName] as $listener) {
+                $listener->execute($data); // TODO: keep an history of executed actions for unit test
+            }
+        }
+    }
+
+    /**
+     * Get the last fired event
+     *
+     * @access public
+     * @return string Event name
+     */
+    public function getLastTriggeredEvent()
+    {
+        return $this->lastEvent;
+    }
+
+    /**
+     * Get a list of triggered events
+     *
+     * @access public
+     * @return array
+     */
+    public function getTriggeredEvents()
+    {
+        return $this->events;
+    }
+
+    /**
+     * Check if a listener bind to an event
+     *
+     * @access public
+     * @param  string $eventName    Event name
+     * @param  mixed  $instance     Instance name or object itself
+     * @return bool                 Yes or no
+     */
+    public function hasListener($eventName, $instance)
+    {
+        if (isset($this->listeners[$eventName])) {
+            foreach ($this->listeners[$eventName] as $listener) {
+                if ($listener instanceof $instance) {
+                    return true;
+                }
+            }
+        }
+
+        return false;
+    }
+}