Filter refactoring

app/Formatter/BaseTaskCalendarFormatter.php

@@ -0,0 +1,45 @@
+<?php
+
+namespace Kanboard\Formatter;
+
+use Kanboard\Core\Filter\FormatterInterface;
+
+/**
+ * Common class to handle calendar events
+ *
+ * @package  formatter
+ * @author   Frederic Guillot
+ */
+abstract class BaseTaskCalendarFormatter extends BaseFormatter
+{
+    /**
+     * Column used for event start date
+     *
+     * @access protected
+     * @var string
+     */
+    protected $startColumn = 'date_started';
+
+    /**
+     * Column used for event end date
+     *
+     * @access protected
+     * @var string
+     */
+    protected $endColumn = 'date_completed';
+
+    /**
+     * Transform results to calendar events
+     *
+     * @access public
+     * @param  string  $start_column    Column name for the start date
+     * @param  string  $end_column      Column name for the end date
+     * @return FormatterInterface
+     */
+    public function setColumns($start_column, $end_column = '')
+    {
+        $this->startColumn = $start_column;
+        $this->endColumn = $end_column ?: $start_column;
+        return $this;
+    }
+}