refactor(admin): remove hardcoded email and dynamically resolve admin privileges via Firestore Admins collection

firestore.rules

@@ -10,7 +10,8 @@ service cloud.firestore {
     function isAdmin() {
       return request.auth != null && (
         request.auth.token.admin == true ||
-        request.auth.token.email == 'nicolas@gruber.info'
+        exists(/databases/$(database)/documents/Admins/$(request.auth.uid)) ||
+        (request.auth.token.email != null && exists(/databases/$(database)/documents/Admins/$(request.auth.token.email)))
       );
     }
 
@@ -22,6 +23,12 @@ service cloud.firestore {
       );
     }
 
+    // Admins-Sammlung: Angemeldete Nutzer können prüfen, nur Admins schreiben
+    match /Admins/{adminDoc} {
+      allow read: if isAuthenticated();
+      allow write: if isAdmin();
+    }
+
     // Öffentliche Sammlungen: News, Mängel (Issues) & Ideen (CitizensForum)
     match /{collection}/{document=**} {
       // Jeder darf News, Mängel & Ideen öffentlich lesen

lib/services/auth_service.dart

@@ -1,5 +1,6 @@
-import 'package:flutter/foundation.dart';
+import 'package:cloud_firestore/cloud_firestore.dart';
 import 'package:firebase_auth/firebase_auth.dart';
+import 'package:flutter/foundation.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
 class AuthService extends ChangeNotifier {
@@ -47,21 +48,64 @@ class AuthService extends ChangeNotifier {
     _initAuth();
   }
 
-  static const List<String> adminEmails = [
-    'nicolas@gruber.info',
-  ];
-
   Future<void> _checkAdminClaim(User? user) async {
     if (user != null && !user.isAnonymous) {
-      final email = user.email?.trim().toLowerCase();
-      if (email != null && adminEmails.contains(email)) {
+      try {
+        // 1. Custom claims check (token.admin == true)
+        final tokenResult = await user.getIdTokenResult();
+        if (tokenResult.claims?['admin'] == true) {
           _isAdmin = true;
           return;
         }
-      try {
-        final tokenResult = await user.getIdTokenResult();
-        _isAdmin = tokenResult.claims?['admin'] == true;
-      } catch (_) {
+
+        final firestore = FirebaseFirestore.instance;
+
+        // 2. Check Firestore 'Admins' collection by user UID (doc id)
+        final docByUid =
+            await firestore.collection('Admins').doc(user.uid).get();
+        if (docByUid.exists) {
+          _isAdmin = true;
+          return;
+        }
+
+        // 3. Check Firestore 'Admins' collection by email (doc id)
+        final userEmail = user.email?.trim().toLowerCase();
+        if (userEmail != null && userEmail.isNotEmpty) {
+          final docByEmail =
+              await firestore.collection('Admins').doc(userEmail).get();
+          if (docByEmail.exists) {
+            _isAdmin = true;
+            return;
+          }
+
+          // 4. Check Firestore 'Admins' collection where email field == userEmail
+          final queryByEmail = await firestore
+              .collection('Admins')
+              .where('email', isEqualTo: userEmail)
+              .limit(1)
+              .get();
+          if (queryByEmail.docs.isNotEmpty) {
+            _isAdmin = true;
+            return;
+          }
+        }
+
+        // 5. Check Firestore 'Admins' collection where uid field == user.uid
+        final queryByUid = await firestore
+            .collection('Admins')
+            .where('uid', isEqualTo: user.uid)
+            .limit(1)
+            .get();
+        if (queryByUid.docs.isNotEmpty) {
+          _isAdmin = true;
+          return;
+        }
+
+        _isAdmin = false;
+      } catch (e) {
+        if (kDebugMode) {
+          debugPrint('Error checking admin status: $e');
+        }
         _isAdmin = false;
       }
     } else {

storage.rules

@@ -15,8 +15,7 @@ service firebase.storage {
       // Nur der Verfasser oder ein Admin darf sein Foto löschen
       allow delete: if request.auth != null && (
         request.auth.uid == userId ||
-        request.auth.token.admin == true ||
-        request.auth.token.email == 'nicolas@gruber.info'
+        request.auth.token.admin == true
       );
     }
   }