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

from bu4.combinatory.lcombinatory import LCombinatory
from bu4.combinatory.lic import LIC
from bu4.combinatory.lkc import LKC
from bu4.combinatory.lsc import LSC
from bu4.linking.constructs.lcall import LCall
from bu4.linking.constructs.ldelayed import LDelayed
from bu4.linking.constructs.lexception import LException
from bu4.linking.constructs.linked import Linked
from bu4.linking.constructs.llambda import LLambda
from bu4.linking.constructs.lname import LName
from bu4.linking.constructs.lnull import LNull
from bu4.transform.states.aftertransform import AfterTransform
from bu4.transform.states.transformfinished import TransformFinished
from bu4.transform.states.transformstart import TransformStart
from bu4.transform.states.transformstate import TransformState
from bu4.transform.targets.atlambda import ATLambda


class LCCall(LCall, LCombinatory):
    def __init__(self, argument: LCombinatory, lambda_: LCombinatory):
        super().__init__(argument, lambda_)


class LCNull(LNull, LCombinatory):
    pass


class LCException(LException, LCombinatory):
    pass


def is_kks(linked: Linked) -> bool:
    if not isinstance(linked, LCall):
        return False
    if not isinstance(linked.lambda_, LSC):
        return False
    linked = linked.argument
    if not isinstance(linked, LCall):
        return False
    if not isinstance(linked.argument, LKC):
        return False
    if not isinstance(linked.lambda_, LKC):
        return False
    return True


def is_ikks(linked: Linked) -> bool:
    if not isinstance(linked, LCall):
        return False
    if not isinstance(linked.argument, LIC):
        return False
    return is_kks(linked.lambda_)


def is_eta(linked: Linked) -> bool:
    if not isinstance(linked, LCall):
        return False
    if not isinstance(linked.argument, LKC):
        return False
    linked = linked.lambda_
    if not isinstance(linked, LCall):
        return False
    if not isinstance(linked.lambda_, LSC):
        return False
    linked = linked.argument
    if not isinstance(linked, LCall):
        return False
    if not isinstance(linked.lambda_, LKC):
        return False
    linked = linked.argument
    if not isinstance(linked, LCall):
        return False
    if not isinstance(linked.argument, LIC):
        return False
    if not isinstance(linked.lambda_, LSC):
        return False
    return True


def lccall(argument: Linked, lambda_: Linked) -> TransformState[Linked]:
    if isinstance(lambda_, LIC):
        return TransformFinished(argument)
    elif isinstance(argument, LKC) and isinstance(lambda_, LSC):
        return TransformFinished(LCCall(LIC(), LKC()))
    elif isinstance(lambda_, LCall) and isinstance(lambda_.lambda_, LKC):
        return TransformFinished(lambda_.argument)
    elif isinstance(argument, LIC) and is_kks(lambda_):
        return TransformFinished(LKC())
    elif isinstance(lambda_, LCall) and is_eta(lambda_.lambda_):
        lcall = lambda_
        return TransformStart(lambda: lccall(lcall.argument, argument))
    elif isinstance(argument, LCombinatory) and isinstance(lambda_, LCombinatory):
        return TransformFinished(LCCall(argument, lambda_))
    else:
        return TransformFinished(LCall.new(argument, lambda_))


def to_combinatory(linked: Linked) -> TransformState[Linked]:
    if isinstance(linked, LCombinatory):
        return TransformFinished(linked)
    elif is_ikks(linked):
        return TransformFinished(LKC())
    elif isinstance(linked, LCall):
        lcall = linked
        return AfterTransform(
            TransformStart(lambda: to_combinatory(lcall.argument)),
            ATLambda(
                lambda argument: AfterTransform(
                    TransformStart(lambda: to_combinatory(lcall.lambda_)),
                    ATLambda(
                        lambda lambda_: lccall(argument, lambda_)
                    )
                )
            )
        )
    elif isinstance(linked, LDelayed):
        ldelayed = linked
        return AfterTransform(
            TransformStart(lambda: to_combinatory(ldelayed.value)),
            ATLambda(
                lambda value: lccall(value, LKC())
            )
        )
    elif isinstance(linked, LLambda):
        llambda = linked
        if not llambda.used:
            return AfterTransform(
                TransformStart(lambda: to_combinatory(llambda.value)),
                ATLambda(
                    lambda value: lccall(value, LKC())
                )
            )
        elif isinstance(llambda.value, LName) and llambda.value.name == llambda.name:
            return TransformFinished(LIC())
        elif isinstance(llambda.value, LCall):
            lcall = llambda.value
            return AfterTransform(
                TransformStart(lambda: to_combinatory(LLambda(llambda.name, lcall.argument))),
                ATLambda(
                    lambda argument: AfterTransform(
                        TransformStart(lambda: to_combinatory(LLambda(llambda.name, lcall.lambda_))),
                        ATLambda(
                            lambda lambda_: AfterTransform(
                                lccall(
                                    lambda_,
                                    LSC()
                                ),
                                ATLambda(
                                    lambda combined: lccall(
                                        argument,
                                        combined
                                    )
                                )
                            )
                        )
                    )
                )
            )
        else:
            return AfterTransform(
                TransformStart(lambda: to_combinatory(llambda.value)),
                ATLambda(
                    lambda value: to_combinatory(LLambda(llambda.name, value))
                )
            )
    elif isinstance(linked, LNull):
        return TransformFinished(LCNull())
    elif isinstance(linked, LException):
        return TransformFinished(LCException(linked.name))
    else:
        return TransformFinished(linked)