✨ Add addToMine functionality to Meetups API for adding meetups to a user's "My Meetups" list

- 🔒 Introduce `addToMine` policy for authenticated users to add existing meetups.
- ✏️ Add `addToMine` method in `MeetupController` with idempotent handling.
- ✨ Include `addMember` utility in `Meetup` model for managing pivot relationships.
- 🛠️ Refactor `AddMeetupToMineTool` to use `addMember` for consistency.
- 🧪 Add feature tests for `addToMine`, covering idempotency, permissions, and unknown slugs.
- 🌐 Register `addToMine` route in API and link it to `MeetupController`.

app/Http/Controllers/Api/MeetupController.php

@@ -122,6 +122,27 @@ class MeetupController extends Controller
         return MeetupResource::collection($meetups);
     }
 
+    /**
+     * Bestehendes Meetup zu „Meine Meetups" hinzufügen
+     *
+     * Fügt ein bereits existierendes Meetup zur „Meine Meetups"-Liste des authentifizierten
+     * Nutzers hinzu (meetup_user-Pivot als Mitglied, is_leader=false). Idempotent: ein bereits
+     * hinzugefügtes Meetup bleibt unverändert. Die Stammdaten bleiben dem Ersteller vorbehalten.
+     */
+    #[Response(status: 401, description: 'Nicht authentifiziert.')]
+    public function addToMine(Request $request, Meetup $meetup): JsonResponse
+    {
+        Gate::authorize('addToMine', $meetup);
+
+        $wasAdded = $meetup->addMember($request->user());
+
+        return MeetupResource::make($meetup)
+            ->response()
+            ->setStatusCode($wasAdded
+                ? \Symfony\Component\HttpFoundation\Response::HTTP_CREATED
+                : \Symfony\Component\HttpFoundation\Response::HTTP_OK);
+    }
+
     /**
      * Eigenes Meetup anzeigen
      *

app/Mcp/Tools/Meetup/AddMeetupToMineTool.php

@@ -39,17 +39,13 @@ class AddMeetupToMineTool extends Tool
             }
         }
 
-        $alreadyMember = $meetup->users()->whereKey($user->getAuthIdentifier())->exists();
-
-        $meetup->users()->syncWithoutDetaching([
-            $user->getAuthIdentifier() => ['is_leader' => false],
-        ]);
+        $wasAdded = $meetup->addMember($user);
 
         return Response::json([
             'meetup' => MeetupResource::make($meetup)->resolve(),
-            'message' => $alreadyMember
-                ? '„'.$meetup->name.'" war bereits Teil deiner Meetups.'
-                : '„'.$meetup->name.'" wurde zu deinen Meetups hinzugefügt.',
+            'message' => $wasAdded
+                ? '„'.$meetup->name.'" wurde zu deinen Meetups hinzugefügt.'
+                : '„'.$meetup->name.'" war bereits Teil deiner Meetups.',
         ]);
     }
 

app/Models/Meetup.php

@@ -185,6 +185,23 @@ class Meetup extends Model implements HasMedia
         return $this->users()->whereKey($user->id)->exists();
     }
 
+    /**
+     * Den Nutzer als Mitglied (nicht Leader) zu „Meine Meetups" hinzufügen.
+     * Idempotent: ein bereits hinzugefügter Nutzer bleibt unverändert. Gibt
+     * true zurück, wenn neu hinzugefügt (false = war bereits Mitglied).
+     * Geteilt von REST-Controller (addToMine) und MCP-Tool (AddMeetupToMineTool).
+     */
+    public function addMember(User $user): bool
+    {
+        $wasMember = $this->hasMember($user);
+
+        $this->users()->syncWithoutDetaching([
+            $user->getKey() => ['is_leader' => false],
+        ]);
+
+        return ! $wasMember;
+    }
+
     /**
      * RateLimiter-Key für Meetup-Stammdaten-Updates über das Portal-Frontend.
      */

app/Policies/MeetupPolicy.php

@@ -36,6 +36,17 @@ class MeetupPolicy
         return true;
     }
 
+    /**
+     * Ein bestehendes Meetup zu „Meine Meetups" hinzufügen (meetup_user-Pivot als
+     * Mitglied, nicht als Leader). Jeder authentifizierte Nutzer darf das — die
+     * Stammdaten bleiben dem Ersteller vorbehalten (siehe update()). Spiegelt die
+     * offene Semantik des AddMeetupToMineTool (MCP).
+     */
+    public function addToMine(User $user, Meetup $meetup): bool
+    {
+        return true;
+    }
+
     public function update(User $user, Meetup $meetup): bool
     {
         return $this->owns($user, $meetup);

routes/api.php

@@ -73,6 +73,7 @@ Route::middleware('auth:sanctum')
         Route::post('meetup', [MeetupController::class, 'store'])->name('meetup.store');
         Route::patch('meetup/{meetup}', [MeetupController::class, 'update'])->name('meetup.update');
         Route::get('my-meetups', [MeetupController::class, 'mine'])->name('meetup.mine');
+        Route::post('my-meetups/{meetup:slug}', [MeetupController::class, 'addToMine'])->name('meetup.mine.add');
         Route::get('my-meetups/{meetup}', [MeetupController::class, 'mineShow'])->name('meetup.mine.show');
 
         Route::post('meetup-events', [MeetupEventController::class, 'store'])->name('meetup-events.store');

tests/Feature/Api/MeetupWriteApiTest.php

@@ -112,3 +112,44 @@ it('forbids viewing a meetup the user has not selected in mine show', function (
 
     $this->getJson('/api/my-meetups/'.$meetup->id)->assertForbidden();
 });
+
+it('rejects a guest adding a meetup to mine', function () {
+    $meetup = Meetup::factory()->create();
+
+    $this->postJson('/api/my-meetups/'.$meetup->slug)->assertUnauthorized();
+});
+
+it('lets an authenticated user add an existing foreign meetup to mine by slug', function () {
+    $owner = User::factory()->create();
+    $meetup = Meetup::factory()->create(['created_by' => $owner->id]);
+
+    Sanctum::actingAs($user = User::factory()->create());
+
+    $this->postJson('/api/my-meetups/'.$meetup->slug)
+        ->assertCreated()
+        ->assertJsonPath('data.id', $meetup->id);
+
+    $this->assertDatabaseHas('meetup_user', [
+        'meetup_id' => $meetup->id,
+        'user_id' => $user->id,
+        'is_leader' => false,
+    ]);
+});
+
+it('is idempotent and returns 200 when the meetup is already mine', function () {
+    Sanctum::actingAs($user = User::factory()->create());
+    $meetup = Meetup::factory()->create();
+    $user->meetups()->attach($meetup, ['is_leader' => false]);
+
+    $this->postJson('/api/my-meetups/'.$meetup->slug)
+        ->assertOk()
+        ->assertJsonPath('data.id', $meetup->id);
+
+    expect($user->meetups()->whereKey($meetup->id)->count())->toBe(1);
+});
+
+it('returns 404 for an unknown meetup slug', function () {
+    Sanctum::actingAs(User::factory()->create());
+
+    $this->postJson('/api/my-meetups/does-not-exist-9999')->assertNotFound();
+});