🌐 Add German translations and implement calendar streaming functionality

app/Http/Controllers/DownloadMeetupCalendar.php

@@ -0,0 +1,62 @@
+<?php
+
+namespace App\Http\Controllers;
+
+use App\Models\Meetup;
+use App\Models\MeetupEvent;
+use Illuminate\Http\Request;
+use Illuminate\Http\Response;
+use Spatie\IcalendarGenerator\Components\Calendar;
+use Spatie\IcalendarGenerator\Components\Event;
+
+class DownloadMeetupCalendar extends Controller
+{
+    /**
+     * Handle the incoming request.
+     */
+    public function __invoke(Request $request): Response
+    {
+        if ($request->has('meetup')) {
+            $meetup = Meetup::query()
+                            ->with([
+                                'meetupEvents.meetup',
+                            ])
+                            ->findOrFail($request->input('meetup'));
+            $events = $meetup->meetupEvents;
+            $image = $meetup->getFirstMediaUrl('logo');
+        } elseif ($request->has('my')) {
+            $ids = $request->input('my');
+            $events = MeetupEvent::query()
+                                 ->with([
+                                     'meetup',
+                                 ])
+                                 ->whereHas('meetup', fn($query) => $query->whereIn('meetups.id', $ids))
+                                 ->get();
+            $image = asset('img/einundzwanzig-horizontal.png');
+        } else {
+            $events = MeetupEvent::query()
+                                 ->with([
+                                     'meetup',
+                                 ])
+                                 ->get();
+            $image = asset('img/einundzwanzig-horizontal.png');
+        }
+
+        $entries = [];
+        foreach ($events as $event) {
+            $entries[] = Event::create($event->meetup->name)
+                              ->uniqueIdentifier(str($event->meetup->name)->slug().$event->id)
+                              ->address($event->location ?? __('no location set'))
+                              ->description(str_replace(["\r", "\n"], '', $event->description).' Link: '.$event->link)
+                              ->image($event->meetup->getFirstMedia('logo') ? $event->meetup->getFirstMediaUrl('logo') : $image)
+                              ->startsAt($event->start);
+        }
+
+        $calendar = Calendar::create()
+                            ->refreshInterval(5)
+                            ->event($entries);
+
+        return response($calendar->get())
+            ->header('Content-Type', 'text/calendar; charset=utf-8');
+    }
+}