Filter refactoring

app/Filter/TaskLinkFilter.php

@@ -0,0 +1,85 @@
+<?php
+
+namespace Kanboard\Filter;
+
+use Kanboard\Core\Filter\FilterInterface;
+use Kanboard\Model\Link;
+use Kanboard\Model\Task;
+use Kanboard\Model\TaskLink;
+use PicoDb\Database;
+use PicoDb\Table;
+
+/**
+ * Filter tasks by link name
+ *
+ * @package filter
+ * @author  Frederic Guillot
+ */
+class TaskLinkFilter extends BaseFilter implements FilterInterface
+{
+    /**
+     * Database object
+     *
+     * @access private
+     * @var Database
+     */
+    private $db;
+
+    /**
+     * Set database object
+     *
+     * @access public
+     * @param  Database $db
+     * @return TaskLinkFilter
+     */
+    public function setDatabase(Database $db)
+    {
+        $this->db = $db;
+        return $this;
+    }
+
+    /**
+     * Get search attribute
+     *
+     * @access public
+     * @return string[]
+     */
+    public function getAttributes()
+    {
+        return array('link');
+    }
+
+    /**
+     * Apply filter
+     *
+     * @access public
+     * @return string
+     */
+    public function apply()
+    {
+        $task_ids = $this->getSubQuery()->findAllByColumn('task_id');
+
+        if (! empty($task_ids)) {
+            $this->query->in(Task::TABLE.'.id', $task_ids);
+        } else {
+            $this->query->eq(Task::TABLE.'.id', 0); // No match
+        }
+    }
+
+    /**
+     * Get subquery
+     *
+     * @access protected
+     * @return Table
+     */
+    protected function getSubQuery()
+    {
+        return $this->db->table(TaskLink::TABLE)
+            ->columns(
+                TaskLink::TABLE.'.task_id',
+                Link::TABLE.'.label'
+            )
+            ->join(Link::TABLE, 'id', 'link_id', TaskLink::TABLE)
+            ->ilike(Link::TABLE.'.label', $this->value);
+    }
+}