import logging
logger = logging.getLogger("RoundupExport")
from config import RELAXNG_SCHEMA_FILE
import libxml2

class ErrorHandler:
    def __init__(self):
        self.errors = []

    def handler(self, msg, data):
        self.errors.append(msg)

class ValidateXML(object):
    def __init__(self, xml):
        self.xml = xml

    def validate(self):
        schemaf = open(RELAXNG_SCHEMA_FILE, "r")
        schema = schemaf.read()
        schemaf.close()
        rngp = libxml2.relaxNGNewMemParserCtxt(schema, len(schema))
        rngs = rngp.relaxNGParse()
        ctxt = rngs.relaxNGNewValidCtxt()
        e = ErrorHandler()
        ctxt.setValidityErrorHandler(e.handler, e.handler)
        doc = libxml2.parseDoc(self.xml)
        ret = doc.relaxNGValidateDoc(ctxt)
        if ret != 0 or e.errors:
            logger.debug("Error doing RelaxNG validation")
        else:
            logger.debug("RelaxNG validation successful")
        return e