A mixin handling read-only fields per group, admin model and form type in Django

mixins.py

class FieldPermissionsMixin:
    """
    Define a mixin handling read-only fields per group, admin model and form type.

    !!!THIS IS JUST A DRAFT, AWAITING COMPLETION!!!

    Read-only fields can be specified in a setting exemplified below.
    For permission names, codenames without the model name are considered well-formed.
    
    GROUPS = { 
        "{{group_name}}" : {
            "{{model_name}}" : {
                "permissions" : ("{{permission_name_1}}", "{{permission_name_2}}"),
                "readonly_fields": {
                    "{{field_name}}": {
                        "list_display": "{{readonly_field_name}}",
                        "change_form": "{{readonly_field_name}}"
                    }
                },
                ...
            },
            ...
        },
        ..
    }
    """

    def _get_readonly_fields_for_groups(self, group_names, form_type):
        """Return readonly fields for input groups."""
        model_label = self.model.__name__.lower()
        readonly_fields = {}
        for g in group_names:
            dg = settings.GROUPS[g]
            default_readonly_fields = dg.get(model_label, {}).get("readonly_fields", [])
            for f in default_readonly_fields:
                readonly_field_name = default_readonly_fields[f].get(form_type)
                if readonly_field_name:
                    readonly_fields.update({f: readonly_field_name})
        return readonly_fields

    def _replace_fields_in_collection(self, data, readonly_fields):
        """Walk through fields or fieldsets and replace field with readonly variant."""

        def _traverse_and_replace_data(data, readonly_fields):
            """Traverse and replace data."""
            if isinstance(data, list):
                for d in data:
                    if isinstance(d, str):
                        if d in readonly_fields.keys():
                            idx = data.index(d)
                            data[idx] = readonly_fields[d]
                    else:
                        _traverse_and_replace_data(d, readonly_fields)
            if isinstance(data, dict):
                for _k, v in data.items():
                    _traverse_and_replace_data(v, readonly_fields)

        _traverse_and_replace_data(data, readonly_fields)
        return data

    def get_fields(self, request, obj=None):
        """Return field list with additional readonly fields."""
        form_type = "change_form"
        fields = json.loads(json.dumps(super().get_fields(request, obj)))
        if fields:
            group_names = request.user.groups.all().values_list("name", flat=True)
            additional_readonly_fields = self._get_readonly_fields_for_groups(
                group_names, form_type
            )
            if additional_readonly_fields:
                fields = self._replace_fields_in_collection(
                    fields, additional_readonly_fields
                )
        return fields

    def get_fieldsets(self, request, obj=None):
        """Return fieldset data structure with additional readonly fields."""
        form_type = "change_form"
        fieldsets = json.loads(json.dumps(super().get_fieldsets(request, obj)))
        if fieldsets:
            group_names = request.user.groups.all().values_list("name", flat=True)
            additional_readonly_fields = self._get_readonly_fields_for_groups(
                group_names, form_type
            )
            if additional_readonly_fields:
                fieldsets = self._replace_fields_in_collection(
                    fieldsets, additional_readonly_fields
                )
        return fieldsets

    def get_readonly_fields(self, request, obj=None):
        """Return readonly field list with additional readonly fields."""
        form_type = "change_form"
        readonly_fields = super().get_readonly_fields(request, obj)
        group_names = request.user.groups.all().values_list("name", flat=True)
        additional_readonly_fields = self._get_readonly_fields_for_groups(
            group_names, form_type
        )
        if additional_readonly_fields:
            for _k, v in additional_readonly_fields:
                readonly_fields += v