Add Username Hyphen Validation on Django Admin

Signed-off-by: Kipchirchir Sigei <arapgodsmack@gmail.com>

Author: KipSigei

onadata/apps/main/admin.py

@@ -0,0 +1,61 @@
+# -*- coding: utf-8 -*-
+"""API Django admin amendments."""
+# pylint: disable=imported-auth-user
+from django.contrib import admin
+from django.contrib.auth.admin import UserAdmin
+from django.contrib.auth.forms import UserCreationForm, UserChangeForm
+from django.contrib.auth.models import User
+from django.core.exceptions import ValidationError
+
+
+class BaseCustomUserForm:
+    """
+    Base form class for custom user forms.
+    Contains common logic for validating the username.
+    """
+
+    def clean_username(self):
+        """
+        Clean the username field to ensure it does not contain hyphens.
+        Raises:
+            ValidationError: If the username contains hyphens.
+        Returns:
+            str: The cleaned username.
+        """
+        username = self.cleaned_data["username"]
+        if "-" in username:
+            raise ValidationError("Usernames cannot contain hyphens.")
+        return username
+
+
+class CustomUserCreationForm(BaseCustomUserForm, UserCreationForm):
+    """
+    Custom form for user creation.
+    Inherits from BaseCustomUserForm and UserCreationForm.
+    """
+
+    class Meta(UserCreationForm.Meta):
+        model = User
+
+
+class CustomUserChangeForm(BaseCustomUserForm, UserChangeForm):
+    """
+    Custom form for user change.
+    Inherits from BaseCustomUserForm and UserChangeForm.
+    """
+
+    class Meta(UserChangeForm.Meta):
+        model = User
+
+
+class CustomUserAdmin(UserAdmin):
+    """
+    Custom User admin panel configuration.
+    """
+
+    add_form = CustomUserCreationForm
+    form = CustomUserChangeForm
+
+
+admin.site.unregister(User)
+admin.site.register(User, CustomUserAdmin)