from core.builtin_concepts import BuiltinConcepts
from core.concept import Concept
from core.global_symbols import NotInit
from evaluators.BaseEvaluator import OneReturnValueEvaluator


class PostExecutionEvaluator(OneReturnValueEvaluator):
    """
    Last chance to alter the return_value
    This evaluator is supposed to be a generic evaluator for all rules that must be executed just before
        the aggregations
    As of now, the AUTO_EVAL rule implementation is simply hardcoded
    """

    NAME = "PostExecution"

    def __init__(self):
        super().__init__(self.NAME, [BuiltinConcepts.AFTER_EVALUATION], 90)

    def matches(self, context, return_value):
        evaluation_parents = context.get_parents(lambda c: c.action == BuiltinConcepts.PROCESSING)
        if len(evaluation_parents) > 1:
            return False  # It must be executed only when the top level context

        value = return_value.body
        return isinstance(value, Concept) and context.sheerka.isa(value, context.sheerka.new(BuiltinConcepts.AUTO_EVAL))

    def eval(self, context, return_value):
        # only support the rule for the AUTO_EVAL
        return context.sheerka.ret(
            self.name,
            True,
            self.custom_obj_value(context, return_value.body),
            parents=[return_value])

    @staticmethod
    def custom_obj_value(context, obj):
        """
        get concept inner value.
        You cannot use sheerka.objvalue() as it does not handle container
        And...
        Do not try to make it manage it, it won't work ;-)
        :param context:
        :param obj:
        :return:
        """
        if context.sheerka.is_container(obj):
            return obj

        if isinstance(obj, Concept):
            if isinstance(obj.body, Concept):
                return PostExecutionEvaluator.custom_obj_value(context, obj.body)
            else:
                return obj.body if obj.body != NotInit else obj

        return obj