Feature: [export] Add a list of accompanying periods

src/Bundle/ChillMainBundle/Export/Helper/DateTimeHelper.php

@@ -0,0 +1,60 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * Chill is a software for social workers
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace Chill\MainBundle\Export\Helper;
+
+use DateTime;
+use Exception;
+use Symfony\Contracts\Translation\TranslatorInterface;
+
+class DateTimeHelper
+{
+    private TranslatorInterface $translator;
+
+    public function __construct(TranslatorInterface $translator)
+    {
+        $this->translator = $translator;
+    }
+
+    public function getLabel($header): callable
+    {
+        return function ($value) use ($header) {
+            if ('_header' === $value) {
+                return $this->translator->trans($header);
+            }
+
+            if (null === $value) {
+                return '';
+            }
+
+            // warning: won't work with DateTimeImmutable as we reset time a few lines later
+            $date = DateTime::createFromFormat('Y-m-d', $value);
+            $hasTime = false;
+
+            if (false === $date) {
+                $date = DateTime::createFromFormat('Y-m-d H:i:s', $value);
+                $hasTime = true;
+            }
+
+            // check that the creation could occurs.
+            if (false === $date) {
+                throw new Exception(sprintf('The value %s could '
+                    . 'not be converted to %s', $value, DateTime::class));
+            }
+
+            if (!$hasTime) {
+                $date->setTime(0, 0, 0);
+            }
+
+            return $date;
+        };
+    }
+}