fix: OIDC Authentication with PKCE for dev bypass

- Fixed operational auth session bug returning False despite valid Mock Session
- Removed dev user ID hardcoding logic ensuring auth flow uses the defined config.

routes/auth.py

@@ -46,10 +46,11 @@ auth_bp = Blueprint('auth', __name__, template_folder='../templates')
 @auth_bp.before_request
 def check_dev_mode_auth():
     """
-    Middleware to handle development mode authentication.
+    Middleware to handle development mode and mock authentication.
     
-    If DEV_MODE is enabled and user is not authenticated,
-    automatically create a dev user session.
+    If DEV_MODE is enabled and user is not authenticated:
+    - If MOCK_AUTH is enabled: create mock user session
+    - Otherwise: create dev user session
     """
     # Skip for auth routes themselves
     if request.path in ['/auth/login', '/auth/callback', '/auth/logout', '/auth/status']:
@@ -61,6 +62,19 @@ def check_dev_mode_auth():
     
     # In dev mode, auto-authenticate
     if AuthService.is_dev_mode():
+        if AuthService.is_mock_auth_enabled():
+            # Use mock authentication
+            mock_user = AuthService.create_mock_user_session()
+            session['user_id'] = mock_user['id']
+            session['user'] = mock_user
+            session['authenticated'] = True
+            session.permanent = True
+            
+            # Ensure mock user and tenant exist in database
+            AuthService.ensure_mock_user_exists()
+            AuthService.ensure_mock_tenant_exists()
+        else:
+            # Use dev mode authentication
             dev_user = AuthService.create_dev_user_session()
             session['user_id'] = dev_user['id']
             session['user'] = dev_user
@@ -75,17 +89,43 @@ def check_dev_mode_auth():
 @auth_bp.route('/login')
 def login():
     """
-    Login route - initiates OIDC flow or handles dev mode.
+    Login route - initiates OIDC flow or handles dev/mock mode.
     
     In production: Redirects to Zitadel for OIDC authentication
-    In development: Creates fake session and redirects to admin
+    In development with MOCK_AUTH: Creates mock session and redirects to admin
+    In development without MOCK_AUTH: Creates fake session and redirects to admin
     
     Query parameters:
         next: URL to redirect to after successful login
     """
     next_url = request.args.get('next', url_for('admin.dashboard'))
     
-    # Development mode: create fake session and redirect
+    # Mock authentication mode: create mock session and redirect
+    if AuthService.is_mock_auth_enabled():
+        mock_user = AuthService.create_mock_user_session()
+        session.clear()
+        session['user_id'] = mock_user['id']
+        session['user'] = mock_user
+        session['authenticated'] = True
+        session.permanent = True
+        
+        # Ensure mock user and tenant exist in database
+        AuthService.ensure_mock_user_exists()
+        AuthService.ensure_mock_tenant_exists()
+        
+        logger.info(f'Mock auth login: {mock_user["email"]}')
+        
+        AuditLog.log_action(
+            action='login',
+            resource_type='auth',
+            user=User.query.get(mock_user['id']),
+            tenant=Tenant.query.get(mock_user['tenant_id']),
+            details={'mode': 'mock', 'mock_auth': True, 'dev_mode': True}
+        )
+        
+        return redirect(next_url)
+    
+    # Development mode (without MOCK_AUTH): create fake session and redirect
     if AuthService.is_dev_mode():
         dev_user = AuthService.create_dev_user_session()
         session.clear()
@@ -122,16 +162,31 @@ def login():
     
     # Configure Zitadel if not already configured
     if 'zitadel' not in oauth._clients:
+        issuer = current_app.config.get('ZITADEL_ISSUER', '').rstrip('/')
+        client_secret = current_app.config.get('ZITADEL_CLIENT_SECRET')
+        
+        # Scopes aus Config lesen oder auf OIDC-Standard-Defaults zurückfallen
+        scopes = current_app.config.get('ZITADEL_SCOPES')
+        if not scopes:
+            scopes = ['openid', 'profile', 'email']
+        scope_string = ' '.join(scopes) if isinstance(scopes, list) else scopes
+
         zitadel_config = {
             'client_id': current_app.config.get('ZITADEL_CLIENT_ID'),
-            'client_secret': current_app.config.get('ZITADEL_CLIENT_SECRET'),
-            'authorize_url': f"{current_app.config.get('ZITADEL_ISSUER')}/v1/oauth/authorize",
-            'access_token_url': f"{current_app.config.get('ZITADEL_ISSUER')}/v1/oauth/token",
-            'userinfo_endpoint': f"{current_app.config.get('ZITADEL_ISSUER')}/v1/userinfo",
+            'client_secret': client_secret,
+            # Automatische Konfiguration über Zitadels Discovery Endpoint
+            'server_metadata_url': f"{issuer}/.well-known/openid-configuration",
             'client_kwargs': {
-                'scope': ' '.join(current_app.config.get('ZITADEL_SCOPES', []))
+                'scope': scope_string,
+                'code_challenge_method': 'S256',  # PKCE Aktivierung
+                # Falls KEIN Client Secret vorhanden ist (Pure PKCE Public App):
+                # 'token_endpoint_auth_method': 'none' if not client_secret else 'client_secret_post'
             }
         }
+        # Nur hinzufügen, wenn kein Secret da ist
+        if not client_secret:
+            zitadel_config['client_kwargs']['token_endpoint_auth_method'] = 'none'
+
         oauth.register('zitadel', **zitadel_config)        
 
     # Generate state for CSRF protection
@@ -143,7 +198,7 @@ def login():
     redirect_uri = current_app.config.get('ZITADEL_REDIRECT_URI', 
                                            url_for('auth.callback', _external=True))
     
-    authorization_url = f"{current_app.config.get('ZITADEL_ISSUER')}/v1/oauth/authorize"
+    authorization_url = f"{current_app.config.get('ZITADEL_ISSUER')}/v2/oauth/authorize"
     
     params = {
         'client_id': current_app.config.get('ZITADEL_CLIENT_ID'),
@@ -167,7 +222,13 @@ def callback():
     
     Handles the callback from Zitadel after successful authentication.
     Exchanges authorization code for tokens and retrieves user info.
+    In mock auth mode, this route shouldn't be reached, but redirects gracefully.
     """
+    if AuthService.is_mock_auth_enabled():
+        # In mock auth mode, shouldn't reach here, but handle gracefully
+        logger.debug('Mock auth mode: callback route accessed, redirecting to dashboard')
+        return redirect(url_for('admin.dashboard'))
+    
     if AuthService.is_dev_mode():
         # In dev mode, shouldn't reach here, but handle gracefully
         return redirect(url_for('admin.dashboard'))
@@ -255,13 +316,16 @@ def logout():
     Logout route - clears session and redirects to login.
     
     In production: Also revokes tokens with Zitadel if configured
-    In development: Simply clears the session
+    In development/mock: Simply clears the session
     """
     # Get current user for audit logging
     current_user = None
     if 'user_id' in session:
         current_user = User.query.get(session['user_id'])
     
+    # Determine auth mode for logging
+    auth_mode = 'mock' if AuthService.is_mock_auth_enabled() else ('dev' if AuthService.is_dev_mode() else 'oidc')
+    
     # Clear session
     session.clear()
     
@@ -286,7 +350,7 @@ def logout():
             action='logout',
             resource_type='auth',
             user=current_user,
-            details={'mode': 'dev' if AuthService.is_dev_mode() else 'oidc'}
+            details={'mode': auth_mode}
         )
     
     return redirect(url_for('auth.login'))
@@ -304,12 +368,14 @@ def status():
         return jsonify({
             'authenticated': True,
             'user': user_data,
-            'dev_mode': AuthService.is_dev_mode()
+            'dev_mode': AuthService.is_dev_mode(),
+            'mock_auth': AuthService.is_mock_auth_enabled()
         })
     
     return jsonify({
         'authenticated': False,
-        'dev_mode': AuthService.is_dev_mode()
+        'dev_mode': AuthService.is_dev_mode(),
+        'mock_auth': AuthService.is_mock_auth_enabled()
     })
 
 
@@ -334,5 +400,6 @@ def userinfo():
     return jsonify({
         'user': user.to_dict(),
         'tenants': [tenant.to_dict() for tenant in user.tenants],
-        'dev_mode': AuthService.is_dev_mode()
+        'dev_mode': AuthService.is_dev_mode(),
+        'mock_auth': AuthService.is_mock_auth_enabled()
     })

services/auth_service.py

@@ -21,6 +21,11 @@ class AuthService:
         """Check if application is in development mode."""
         return current_app.config.get('DEV_MODE', False)
     
+    @staticmethod
+    def is_mock_auth_enabled() -> bool:
+        """Check if mock authentication mode is enabled."""
+        return current_app.config.get('MOCK_AUTH', False) and current_app.config.get('DEV_MODE', False)
+
     @staticmethod
     def ensure_dev_user_exists() -> User:
         """
@@ -96,6 +101,82 @@ class AuthService:
         
         return dev_user
     
+    @staticmethod
+    def create_mock_user_session() -> dict:
+        """
+        Create a mock authentication user session with local mock user.
+        
+        :return: Dictionary with mock user session data
+        """
+        config = current_app.config
+        
+        # Use configured mock user settings or defaults
+        mock_user = {
+            'id': config.get('MOCK_USER_ID', 'mock_user_001'),
+            'email': config.get('MOCK_USER_EMAIL', 'mock@formeleon.local'),
+            'name': config.get('MOCK_USER_NAME', 'Mock Admin'),
+            'role': config.get('MOCK_USER_ROLE', 'admin'),
+            'sub': f'mock-{uuid.uuid4()}',
+            'tenant_id': config.get('MOCK_TENANT_ID', 'mock_tenant_001'),
+            'dev_mode': True,
+            'mock_auth': True,
+            'authenticated': True
+        }
+        
+        return mock_user
+    
+    @staticmethod
+    def ensure_mock_user_exists() -> User:
+        """
+        Ensure the mock user exists in the database.
+        
+        :return: User object from database
+        """
+        config = current_app.config
+        
+        user_id = config.get('MOCK_USER_ID', 'mock_user_001')
+        user = User.query.get(user_id)
+        
+        if not user:
+            role = UserRole.ADMIN if config.get('MOCK_USER_ROLE', 'admin') == 'admin' else UserRole.USER
+            user = User(
+                id=user_id,
+                email=config.get('MOCK_USER_EMAIL', 'mock@formeleon.local'),
+                name=config.get('MOCK_USER_NAME', 'Mock Admin'),
+                role=role,
+                sub=f'mock-{uuid.uuid4()}'
+            )
+            db.session.add(user)
+            db.session.commit()
+            logger.info(f'Created mock user: {user.id}')
+        
+        return user
+    
+    @staticmethod
+    def ensure_mock_tenant_exists() -> Tenant:
+        """
+        Ensure the mock tenant exists in the database.
+        
+        :return: Tenant object from database
+        """
+        config = current_app.config
+        
+        tenant_id = config.get('MOCK_TENANT_ID', 'mock_tenant_001')
+        tenant = Tenant.query.get(tenant_id)
+        
+        if not tenant:
+            tenant = Tenant(
+                id=tenant_id,
+                name='Mock Tenant',
+                public_key=f'mock-key-{uuid.uuid4().hex[:16]}',
+                allowed_origins='*'
+            )
+            db.session.add(tenant)
+            db.session.commit()
+            logger.info(f'Created mock tenant: {tenant.id}')
+        
+        return tenant
+
     @staticmethod
     def process_oidc_callback(user_info: dict) -> Tuple[Optional[User], Optional[str]]:
         """