feat: refactor participant card DTOs and labels

src/Service/ServiceLabelFormatter.php

@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Service;
+
+use App\BusProNet\Model\Service;
+
+/**
+ * Formats service labels for form and UI display.
+ */
+final class ServiceLabelFormatter
+{
+    public function formatServiceLabel(Service $service): string
+    {
+        $label = $service->label ?? '';
+
+        if (null === $service->price) {
+            return $label;
+        }
+
+        if (0.0 === $service->price) {
+            return sprintf('%s (inkl.)', $label);
+        }
+
+        if ($service->price < 0) {
+            return sprintf('%s (-%s€ Rabatt)', $label, number_format(abs($service->price), 2, ',', '.'));
+        }
+
+        return sprintf('%s (€%s)', $label, number_format($service->price, 2, ',', '.'));
+    }
+
+    /**
+     * @param array<int, Service> $services
+     */
+    public function formatServiceLabelForServices(string $fallbackLabel, array $services): string
+    {
+        $service = reset($services);
+        if (false === $service) {
+            return $fallbackLabel;
+        }
+
+        if (!($service instanceof Service)) {
+            return $fallbackLabel;
+        }
+
+        return $this->formatServiceLabel($service);
+    }
+}