#  Copyright (c) PARRRATE T&V 2021. All rights reserved.

from bu4.evaluation.av.envtype import envtype
from bu4.evaluation.constructs.evaluable import Evaluable
from bu4.linking.states.linkingfinished import LinkingFinished
from bu4.linking.states.linkingstate import LinkingState
from bu4.parsing.constructs.linked import Linked, Parsed

__all__ = ('PName',)


class LName(Linked):
    def __init__(self, promise: set[bytes], name: bytes):
        assert name in promise, f'undefined: {name}'
        self.name = name
        self.future = {name}

    def link(self) -> LinkingState:
        return LinkingFinished(self)

    def evaluable(self, env: envtype) -> Evaluable:
        return env[self.name]

    def __str__(self):
        return f'[{self.name.decode()}]'

    def unlink(self) -> Parsed:
        return PName(self.name)


class PName(Parsed):
    def __init__(self, name: bytes):
        self.name = name

    def link(self, promise: set[bytes]) -> Linked:
        return LName(promise, self.name)