from core.builtin_concepts import ParserResultConcept
from core.concept import Concept, ConceptParts
from evaluators.BaseEvaluator import OneReturnValueEvaluator
import logging

from parsers.BaseParser import BaseParser

log = logging.getLogger(__name__)


class ConceptEvaluator(OneReturnValueEvaluator):
    def __init__(self):
        super().__init__("Concept Evaluator", 50)

    def matches(self, context, return_value):
        return return_value.status and \
               return_value.who.startswith(BaseParser.PREFIX) and \
               isinstance(return_value.value, Concept) and \
               not isinstance(return_value.value, ParserResultConcept)  # because there are specific evaluators

    def eval(self, context, return_value):
        sheerka = context.sheerka
        concept = return_value.value

        # pre condition should already be validated by the parser.
        # It's a mandatory condition for the concept before it can be recognized

        if len(concept.codes) == 0:
            sheerka.add_codes_to_concept(context, concept)

        # TODO; check pre
        # if pre is not true, return Concept with a false value

        if ConceptParts.BODY in concept.codes:
            body = concept.codes[ConceptParts.BODY]
            if body is None:
                return None  # nothing to do

            return sheerka.ret(self.name, True, body.value, parents=[return_value])

        else:
            return sheerka.ret(self.name, True, concept, parents=[return_value])