from xform_instance_parser import parse_xform_instance


class SurveyInstance(object):

    def __init__(self, survey_object, **kwargs):
        self._survey = survey_object
        self.kwargs = kwargs #not sure what might be passed to this

        #does the survey object provide a way to get the key dicts?
        self._keys = [c.name for c in self._survey.children]

        self._name = self._survey.name
        self._id = self._survey.id_string

        # get xpaths
        #  - prep for xpaths.
        self._survey.xml()
        self._xpaths = self._survey._xpath.values()
        
        #see "answers(self):" below for explanation of this dict
        self._answers = {}
        self._orphan_answers = {}
    
    def keys(self):
        return self._keys
    
    def xpaths(self):
        #originally thought of having this method get the xpath stuff
        #but survey doesn't like when xml() is called multiple times.
        return self._xpaths

    def answer(self, name=None, value=None):
        if name is None:
            raise Exception("In answering, name must be given")
        
        #ahh. this is horrible, but we need the xpath dict in survey to be up-to-date
        #...maybe
      # self._survey.xml()


        if name in self._survey._xpath.keys():
            self._answers[name] = value
        else:
            self._orphan_answers[name] = value

    def to_json_dict(self):
        children = []
        for k, v in self._answers.items():
            children.append({'node_name':k, 'value':v})
        return {
            'node_name': self._name,
            'id': self._id,
            'children': children
        }
        
    def to_xml(self):
        """
        A horrible way to do this, but it works (until we need the attributes pumped out in order, etc)
        """
        open_str = """<?xml version='1.0' ?><%s id="%s">""" % (self._name, self._id)
        close_str = """</%s>""" % self._name
        vals = ""
        for k, v in self._answers.items():
            vals += "<%s>%s</%s>" % (k, str(v), k)
        
        output = open_str + vals + close_str
        return output

    def answers(self):
        """
        This returns "_answers", which is a dict with the key-value
        responses for this given instance. This could be pumped to xml
        or returned as a dict for maximum convenience (i.e. testing.)
        """
        return self._answers
        
    def import_from_xml(self, xml_string_or_filename):
        import os.path
        if os.path.isfile(xml_string_or_filename):
            xml_str = open(xml_string_or_filename).read()
        else:
            xml_str = xml_string_or_filename
        key_val_dict = parse_xform_instance(xml_str)
        for k, v in key_val_dict.items():
            self.answer(name=k, value=v)
        
    def __unicode__(self):
        orphan_count = len(self._orphan_answers.keys())
        placed_count = len(self._answers.keys())
        answer_count = orphan_count + placed_count
        return "<Instance (%d answers: %d placed. %d orphans)>" % (answer_count, placed_count, orphan_count)