auth_fc: separate link from login use case (#52929)

src/authentic2_auth_fc/views.py

@@ -391,30 +391,36 @@ class LoginOrLinkView(PopupViewMixin, FcOAuthSessionViewMixin, View):
             messages.error(request, _('Your account is disabled.'))
         return self.redirect(request)
 
-    def get(self, request, *args, **kwargs):
+    def link(self, request):
         '''Request an access grant code and associate it to the current user'''
-        self.service = get_service_from_request(request)
+        try:
+            self.fc_account, created = models.FcAccount.objects.get_or_create(
+                sub=self.sub, user=request.user, order=0, defaults={'token': json.dumps(self.token)}
+            )
+            # Prevent adding a link with an FC account already linked with another user.
+        except IntegrityError:
+            # unique index check failed, find why.
+            return self.uniqueness_check_failed(request)
+
+        if created:
+            self.logger.info('fc link created sub %s', self.sub)
+            messages.info(
+                request, _('Your FranceConnect account {} has been linked.').format(self.fc_display_name)
+            )
+            hooks.call_hooks('event', name='fc-link', user=request.user, sub=self.sub, request=request)
+        else:
+            messages.info(request, _('Your local account has been updated.'))
+        self.update_user_info()
+        return self.redirect(request)
+
+    def get(self, request, *args, **kwargs):
         if request.user.is_authenticated:
-            # Prevent to add a link with an FC account already linked with another user.
-            try:
-                self.fc_account, created = models.FcAccount.objects.get_or_create(
-                    sub=self.sub, user=request.user, order=0, defaults={'token': json.dumps(self.token)}
-                )
-            except IntegrityError:
-                # unique index check failed, find why.
-                return self.uniqueness_check_failed(request)
-
-            if created:
-                self.logger.info('fc link created sub %s', self.sub)
-                messages.info(
-                    request, _('Your FranceConnect account {} has been linked.').format(self.fc_display_name)
-                )
-                hooks.call_hooks('event', name='fc-link', user=request.user, sub=self.sub, request=request)
-            else:
-                messages.info(request, _('Your local account has been updated.'))
-            self.update_user_info()
-            return self.redirect(request)
+            return self.link(request)
+        else:
+            return self.login(request)
 
+    def login(self, request):
+        self.service = get_service_from_request(request)
         default_ou = get_default_ou()
         email_is_unique = a2_app_settings.A2_EMAIL_IS_UNIQUE or default_ou.email_is_unique
         email_present_and_unique = self.user_info.get('email') and email_is_unique