language specific money and date display (#180)

* improved date translation
* language specific date and money display

src/Twig/DateExtensions.php

@@ -0,0 +1,88 @@
+<?php
+
+/*
+ * This file is part of the Kimai time-tracking app.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace App\Twig;
+
+use DateTime;
+use Symfony\Component\HttpFoundation\RequestStack;
+use Twig\TwigFilter;
+
+/**
+ * Date specific twig extensions
+ */
+class DateExtensions extends \Twig_Extension
+{
+    private const FALLBACK_SHORT = 'Y-m-d';
+
+    /**
+     * @var array
+     */
+    protected $dateSettings;
+
+    /**
+     * @var RequestStack
+     */
+    protected $requestStack;
+
+    /**
+     * DateExtensions constructor.
+     * @param RequestStack $requestStack
+     * @param array $dateSettings
+     */
+    public function __construct(RequestStack $requestStack, array $dateSettings)
+    {
+        $this->requestStack = $requestStack;
+        $this->dateSettings = $dateSettings;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function getFilters()
+    {
+        return [
+            new TwigFilter('month_name', [$this, 'monthName']),
+            new TwigFilter('date_short', [$this, 'dateShort']),
+        ];
+    }
+
+    /**
+     * @return string
+     */
+    protected function getLocale()
+    {
+        return $this->requestStack->getCurrentRequest()->getLocale();
+    }
+
+    /**
+     * @param array $context
+     * @param DateTime $date
+     * @return string
+     */
+    public function dateShort(DateTime $date)
+    {
+        $locale = $this->getLocale();
+        $format = self::FALLBACK_SHORT;
+
+        if (isset($this->dateSettings[$locale]['date_short'])) {
+            $format = $this->dateSettings[$locale]['date_short'];
+        }
+
+        return date_format($date, $format);
+    }
+
+    /**
+     * @param \DateTime $date
+     * @return string
+     */
+    public function monthName(\DateTime $date)
+    {
+        return 'month.' . $date->format('n');
+    }
+}