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


class ConceptEvaluator(OneReturnValueEvaluator):
    """
    The concept evaluatuor is the main class that know what to do with a concept
    It verifies the PRE
    If ok, can execute or not the BODY
    Then checks the POST conditions
    """
    NAME = "Concept"
    evaluation_steps = [
        BuiltinConcepts.BEFORE_EVALUATION,
        BuiltinConcepts.EVALUATION,
        BuiltinConcepts.AFTER_EVALUATION
    ]

    def __init__(self):
        super().__init__(self.NAME, 50)

    def matches(self, context, return_value):
        return return_value.status and \
               isinstance(return_value.value, ParserResultConcept) and \
               isinstance(return_value.value.value, Concept)

    def eval(self, context, return_value):
        sheerka = context.sheerka
        concept = return_value.value.value
        context.log(self.verbose_log, f"Evaluating concept {concept}.", self.name)

        # If the concept that is requested is in the context(at least its name), drop the call.
        # Why ?
        # If we evaluate Concept("foo", body="a").set_prop("a", "'property_a'")
        # The body should be 'property_a', and not a concept called a in our universe
        if context.obj and concept.name in context.obj.props:
            return sheerka.ret(self.name, False, sheerka.new(BuiltinConcepts.NOT_FOR_ME), parents=[return_value])

        evaluated = sheerka.evaluate_concept(context, concept, self.verbose_log)

        if evaluated.key != concept.key:
            # evaluated.key != concept.key means that we have transformed the concept
            # When you successfully evaluate an error, the status should not be false
            return sheerka.ret(
                self.name,
                False,
                evaluated,
                parents=[return_value])

        if ConceptParts.BODY not in evaluated.cached_asts:
            return sheerka.ret(self.name, True, evaluated, parents=[return_value])
        else:
            return sheerka.ret(self.name, True, evaluated.body, parents=[return_value])