Subtasks events refactoring and show delete in activity stream

app/EventBuilder/SubtaskEventBuilder.php

@@ -0,0 +1,79 @@
+<?php
+
+namespace Kanboard\EventBuilder;
+
+use Kanboard\Event\SubtaskEvent;
+use Kanboard\Event\GenericEvent;
+
+/**
+ * Class SubtaskEventBuilder
+ *
+ * @package Kanboard\EventBuilder
+ * @author  Frederic Guillot
+ */
+class SubtaskEventBuilder extends BaseEventBuilder
+{
+    /**
+     * SubtaskId
+     *
+     * @access protected
+     * @var int
+     */
+    protected $subtaskId = 0;
+
+    /**
+     * Changed values
+     *
+     * @access protected
+     * @var array
+     */
+    protected $values = array();
+
+    /**
+     * Set SubtaskId
+     *
+     * @param  int $subtaskId
+     * @return $this
+     */
+    public function withSubtaskId($subtaskId)
+    {
+        $this->subtaskId = $subtaskId;
+        return $this;
+    }
+
+    /**
+     * Set values
+     *
+     * @param  array $values
+     * @return $this
+     */
+    public function withValues(array $values)
+    {
+        $this->values = $values;
+        return $this;
+    }
+
+    /**
+     * Build event data
+     *
+     * @access public
+     * @return GenericEvent|null
+     */
+    public function build()
+    {
+        $eventData = array();
+        $eventData['subtask'] = $this->subtaskModel->getById($this->subtaskId, true);
+
+        if (empty($eventData['subtask'])) {
+            $this->logger->debug(__METHOD__.': Subtask not found');
+            return null;
+        }
+
+        if (! empty($this->values)) {
+            $eventData['changes'] = array_diff_assoc($this->values, $eventData['subtask']);
+        }
+
+        $eventData['task'] = $this->taskFinderModel->getDetails($eventData['subtask']['task_id']);
+        return new SubtaskEvent($eventData);
+    }
+}