from enum import IntEnum


def validate(json_object):
    results = ValidationResults()

    if "$schemaRef" not in json_object:
        results.add(ValidationSeverity.FATAL, JsonValidationException("No $schemaRef found, unable to validate."))

    return results


class ValidationSeverity(IntEnum):
    OK = 0,
    WARN = 1,
    ERROR = 2,
    FATAL = 3


class ValidationResults(object):

    severity = ValidationSeverity.OK
    messages = []

    def add(self, severity, exception):
        self.severity = max(severity, self.severity)
        self.messages.append(exception)


class JsonValidationException(Exception):
    pass