From 8239f777ec34a19dcd02ef00e02dd54605de1b23 Mon Sep 17 00:00:00 2001
From: Pedro Crespo-Valero <32402063+pcrespov@users.noreply.github.com>
Date: Wed, 30 Oct 2024 13:15:16 +0100
Subject: [PATCH] generalized

---
 .../api_schemas_webserver/groups.py           | 24 ++++++++------
 .../models_library/utils/common_validators.py | 32 +++++++++++++++++++
 2 files changed, 46 insertions(+), 10 deletions(-)

diff --git a/packages/models-library/src/models_library/api_schemas_webserver/groups.py b/packages/models-library/src/models_library/api_schemas_webserver/groups.py
index f83bc5386086..13bfe711dfb5 100644
--- a/packages/models-library/src/models_library/api_schemas_webserver/groups.py
+++ b/packages/models-library/src/models_library/api_schemas_webserver/groups.py
@@ -10,9 +10,10 @@
     root_validator,
     validator,
 )
-from simcore_service_webserver.db.base_repository import UserID
 
 from ..emails import LowerCaseEmailStr
+from ..users import UserID
+from ..utils.common_validators import create__only_one_is_set__root_validator
 from ._base import InputSchema, OutputSchema
 
 
@@ -182,15 +183,18 @@ class GroupUserAdd(InputSchema):
     uid: UserID | None = None
     email: LowerCaseEmailStr | None = None
 
-    @root_validator
-    @classmethod
-    def _check_uid_or_email(cls, values):
-        uid, email = values.get("uid"), values.get("email")
-        # Ensure exactly one of uid or email is set
-        if not (bool(uid is not None) ^ bool(email is not None)):
-            msg = f"Either 'uid' or 'email' must be set, but not both. Got {uid=} and {email=}"
-            raise ValueError(msg)
-        return values
+    _check_uid_or_email = root_validator(allow_reuse=True)(
+        create__only_one_is_set__root_validator(["uid", "email"])
+    )
+    # @root_validator
+    # @classmethod
+    # def _check_uid_or_email(cls, values):
+    #     uid, email = values.get("uid"), values.get("email")
+    #     # Ensure exactly one of uid or email is set
+    #     if not (bool(uid is not None) ^ bool(email is not None)):
+    #         msg = f"Either 'uid' or 'email' must be set, but not both. Got {uid=} and {email=}"
+    #         raise ValueError(msg)
+    #     return values
 
 
 class GroupUserUpdate(InputSchema):
diff --git a/packages/models-library/src/models_library/utils/common_validators.py b/packages/models-library/src/models_library/utils/common_validators.py
index c60586dfa92c..baf09445ffe8 100644
--- a/packages/models-library/src/models_library/utils/common_validators.py
+++ b/packages/models-library/src/models_library/utils/common_validators.py
@@ -16,6 +16,8 @@ class MyModel(BaseModel):
 """
 
 import enum
+import functools
+import operator
 from typing import Any
 
 
@@ -69,3 +71,33 @@ def null_or_none_str_to_none_validator(value: Any):
     if isinstance(value, str) and value.lower() in ("null", "none"):
         return None
     return value
+
+
+def create__only_one_is_set__root_validator(alternative_field_names: list[str]):
+    """Ensure exactly one and only one of the alternatives is set
+
+    This is useful when you want to give the client alternative
+    ways to set the same thing e.g. set the user by email or id or username
+    and each of those has a different field
+
+    NOTE: Alternatevely, the previous example can also be solved using a
+    single field as `user: Email | UserID | UserName`
+
+    SEE test_uid_or_email_are_set.py for more details
+    """
+
+    def _validator(cls, values):
+        assert set(alternative_field_names).issubset(cls.__fields__)  # nosec
+
+        got = {
+            field_name: values.get(field_name) for field_name in alternative_field_names
+        }
+
+        if not functools.reduce(operator.xor, (v is not None for v in got.values())):
+            msg = (
+                f"Either { 'or'.join(got.keys()) } must be set, but not both. Got {got}"
+            )
+            raise ValueError(msg)
+        return values
+
+    return _validator