add meetup event landing page

app/Rules/UniqueAttendeeName.php

@@ -0,0 +1,45 @@
+<?php
+
+namespace App\Rules;
+
+use App\Models\MeetupEvent;
+use Illuminate\Contracts\Validation\InvokableRule;
+
+class UniqueAttendeeName implements InvokableRule
+{
+    /**
+     * Create a new rule instance.
+     * @return void
+     */
+    public function __construct(public MeetupEvent $meetupEvent)
+    {
+        //
+    }
+
+    public function __invoke($attribute, $value, $fail)
+    {
+        $this->meetupEvent->refresh();
+        $attendees = collect($this->meetupEvent->attendees);
+        $mightAttendees = collect($this->meetupEvent->might_attendees);
+        $isInAttendees = $attendees
+            ->contains(fn($v) => str($v)
+                                     ->after('|')
+                                     ->lower()
+                                     ->toString() === str($value)
+                                     ->lower()
+                                     ->toString());
+        $isInMightAttendees = $mightAttendees
+            ->contains(fn($v) => str($v)
+                                     ->after('|')
+                                     ->lower()
+                                     ->toString() === str($value)
+                                     ->lower()
+                                     ->toString());
+        if ($isInAttendees) {
+            $fail('The name is already taken.');
+        }
+        if ($isInMightAttendees) {
+            $fail('The name is already taken.');
+        }
+    }
+}