feat: Refactor account handling and improve group creation logic

lib/repositories/account_repository.dart

@@ -54,9 +54,8 @@ class AccountRepository {
                   .get();
               if (memberDoc.exists) {
                 final accountData = accountDoc.data() as Map<String, dynamic>;
-                final account = Account.fromMap(accountData);
+                final account = Account.fromMap(accountData, accountId); // ✅ Ajout de l'ID
                 final members = await getAccountMembers(accountId);
-
                 userAccounts.add(account.copyWith(members: members));
               } else {
                 _errorService.logInfo('account_repository.dart', 'Utilisateur NON membre de $accountId');
@@ -99,15 +98,44 @@ class AccountRepository {
     }
   }
 
-  Future<DocumentSnapshot> getAccountById(String accountId) async {
-    return await _firestore.collection('accounts').doc(accountId).get();
+  Future<Account?> getAccountById(String accountId) async {
+    try {
+      final doc = await _firestore.collection('accounts').doc(accountId).get();
+      if (doc.exists) {
+        return Account.fromMap(doc.data() as Map<String, dynamic>, doc.id);
+      }
+      return null;
+    } catch (e) {
+      throw Exception('Erreur lors de la récupération du compte: $e');
+    }
+  }
+
+  Future<Account?> getAccountByTripId(String tripId) async {
+    try {
+      final querySnapshot = await _firestore
+          .collection('accounts')
+          .where('tripId', isEqualTo: tripId)
+          .limit(1)
+          .get();
+      
+      if (querySnapshot.docs.isNotEmpty) {
+        final doc = querySnapshot.docs.first;
+        return Account.fromMap(doc.data(), doc.id);
+      }
+      return null;
+    } catch (e) {
+      throw Exception('Erreur lors de la récupération du compte: $e');
+    }
   }
 
   Future<void> updateAccount(String accountId, Account account) async {
     try {
-      await _firestore.collection('accounts').doc(accountId).update(account.toMap());
+      // Mettre à jour la date de modification
+      final updatedAccount = account.copyWith(updatedAt: DateTime.now());
+      await _firestore.collection('accounts').doc(accountId).update(updatedAccount.toMap());
     } catch (e) {
       _errorService.logError('account_repository.dart', 'Erreur lors de la mise à jour du compte: $e');
+      throw Exception('Erreur lors de la mise à jour du compte: $e');
     }
   }
 
@@ -123,13 +151,17 @@ class AccountRepository {
 
       final docId = querySnapshot.docs.first.id;
 
+      // Supprimer tous les membres
       final membersSnapshot = await _membersCollection(docId).get();
       for (var memberDoc in membersSnapshot.docs) {
         await _membersCollection(docId).doc(memberDoc.id).delete();
       }
+      
+      // Supprimer le compte
       await _accountCollection.doc(docId).delete();
     } catch (e) {
       _errorService.logError('account_repository.dart', 'Erreur lors de la suppression du compte: $e');
+      throw Exception('Erreur lors de la suppression du compte: $e');
     }
   }
 
@@ -143,4 +175,27 @@ class AccountRepository {
               .toList(),
         );  
   }
+
+  Stream<Account?> watchAccount(String accountId) {
+    return _accountCollection.doc(accountId).snapshots().map((doc) {
+      if (doc.exists) {
+        return Account.fromMap(doc.data() as Map<String, dynamic>, doc.id);
+      }
+      return null;
+    });
+  }
+
+  Stream<Account?> watchAccountByTripId(String tripId) {
+    return _accountCollection
+        .where('tripId', isEqualTo: tripId)
+        .limit(1)
+        .snapshots()
+        .map((snapshot) {
+          if (snapshot.docs.isNotEmpty) {
+            final doc = snapshot.docs.first;
+            return Account.fromMap(doc.data() as Map<String, dynamic>, doc.id);
+          }
+          return null;
+        });
+  }
 }