Début refacto en MVVM (Login, drawer OK

em2rp/lib/view_model/login_view_model.dart

@@ -0,0 +1,57 @@
+import 'package:flutter/material.dart';
+import 'package:firebase_auth/firebase_auth.dart';
+import '../providers/local_auth_provider.dart';
+import 'package:provider/provider.dart';
+
+class LoginViewModel extends ChangeNotifier {
+  final TextEditingController emailController = TextEditingController();
+  final TextEditingController passwordController = TextEditingController();
+  String errorMessage = '';
+  bool isLoading = false;
+  bool obscurePassword = true;
+  bool highlightPasswordField = false;
+  bool highlightEmailField = false;
+
+  void togglePasswordVisibility() {
+    obscurePassword = !obscurePassword;
+    notifyListeners();
+  }
+
+  Future<void> signIn(BuildContext context) async {
+    final localAuthProvider =
+        Provider.of<LocalAuthProvider>(context, listen: false);
+    isLoading = true;
+    errorMessage = '';
+    highlightPasswordField = false;
+    highlightEmailField = false;
+    notifyListeners();
+
+    try {
+      await localAuthProvider.signInWithEmailAndPassword(
+          emailController.text.trim(), passwordController.text);
+      print('User signed in');
+
+      // Vérifier si le contexte est toujours valide
+      if (context.mounted) {
+        // Utiliser pushReplacementNamed pour une transition propre
+        Navigator.of(context, rootNavigator: true)
+            .pushReplacementNamed('/calendar');
+      }
+    } on FirebaseAuthException catch (e) {
+      isLoading = false;
+      // Gérer les erreurs...
+      notifyListeners();
+    } finally {
+      // S'assurer que isLoading est remis à false même en cas d'erreur inattendue
+      isLoading = false;
+      notifyListeners();
+    }
+  }
+
+  @override
+  void dispose() {
+    emailController.dispose();
+    passwordController.dispose();
+    super.dispose();
+  }
+}