Store comment sorting direction in user metadata

app/Decorator/MetadataCacheDecorator.php

@@ -0,0 +1,96 @@
+<?php
+
+namespace Kanboard\Decorator;
+
+use Kanboard\Core\Cache\CacheInterface;
+use Kanboard\Model\MetadataModel;
+
+/**
+ * Class MetadataCacheDecorator
+ *
+ * @package Kanboard\Decorator
+ * @author  Frederic Guillot
+ */
+class MetadataCacheDecorator
+{
+    /**
+     * @var CacheInterface
+     */
+    protected $cache;
+
+    /**
+     * @var MetadataModel
+     */
+    protected $metadataModel;
+
+    /**
+     * @var string
+     */
+    protected $cachePrefix;
+
+    /**
+     * @var int
+     */
+    protected $entityId;
+
+    /**
+     * Constructor
+     *
+     * @param CacheInterface     $cache
+     * @param MetadataModel      $metadataModel
+     * @param string             $cachePrefix
+     * @param integer            $entityId
+     */
+    public function __construct(CacheInterface $cache, MetadataModel $metadataModel, $cachePrefix, $entityId)
+    {
+        $this->cache = $cache;
+        $this->metadataModel = $metadataModel;
+        $this->cachePrefix = $cachePrefix;
+        $this->entityId = $entityId;
+    }
+
+    /**
+     * Get metadata value by key
+     *
+     * @param  string $key
+     * @param  mixed  $default
+     * @return mixed
+     */
+    public function get($key, $default)
+    {
+        $metadata = $this->cache->get($this->getCacheKey());
+
+        if ($metadata === null) {
+            $metadata = $this->metadataModel->getAll($this->entityId);
+            $this->cache->set($this->getCacheKey(), $metadata);
+        }
+
+        return isset($metadata[$key]) ? $metadata[$key] : $default;
+    }
+
+    /**
+     * Set new metadata value
+     *
+     * @param $key
+     * @param $value
+     */
+    public function set($key, $value)
+    {
+        $this->metadataModel->save($this->entityId, array(
+            $key => $value,
+        ));
+
+        $metadata = $this->metadataModel->getAll($this->entityId);
+        $this->cache->set($this->getCacheKey(), $metadata);
+    }
+
+    /**
+     * Get cache key
+     *
+     * @return string
+     */
+    protected function getCacheKey()
+    {
+        return $this->cachePrefix.$this->entityId;
+    }
+}