from core.builtin_concepts import BuiltinConcepts
from evaluators.BaseEvaluator import OneReturnValueEvaluator


class PrepareEvalEvaluator(OneReturnValueEvaluator):
    """
    To parse evaluation requests
    """

    NAME = "PrepareEval"

    def __init__(self, **kwargs):
        super().__init__(self.NAME, [BuiltinConcepts.BEFORE_PARSING], 90)
        self.text = None

    def matches(self, context, return_value):
        if not (return_value.status and
                context.sheerka.isinstance(return_value.body, BuiltinConcepts.USER_INPUT) and
                isinstance(return_value.body.body, str)):
            return False

        text = return_value.body.body.strip()
        if not text.startswith("eval "):
            return False

        self.text = text
        return True

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

        new_text_to_parse = sheerka.ret(
            self.name,
            True, sheerka.new(BuiltinConcepts.USER_INPUT, body=self.text[5:], user_name=context.event.user))

        evaluation_requested = sheerka.ret(
            self.name,
            True, sheerka.new(BuiltinConcepts.CONCEPT_VALUE_REQUESTED))

        return [new_text_to_parse, evaluation_requested]