from nifty.rg import RGSpace
from nifty.lm import GLSpace, HPSpace, LMSpace

from rgrgtransformation import RGRGTransformation
from gllmtransformation import GLLMTransformation
from hplmtransformation import HPLMTransformation
from lmgltransformation import LMGLTransformation
from lmhptransformation import LMHPTransformation


class _TransformationFactory(object):
    """
        Transform factory which generates transform objects
    """

    def __init__(self):
        # cache for storing the transform objects
        self.cache = {}

    def _get_transform(self, domain, codomain, module):
        if isinstance(domain, RGSpace):
            if isinstance(codomain, RGSpace):
                return RGRGTransformation(domain, codomain, module)
            else:
                raise ValueError('ERROR: incompatible codomain')

        elif isinstance(domain, GLSpace):
            if isinstance(codomain, GLSpace):
                return GLLMTransformation(domain, codomain, module)
            else:
                raise ValueError('ERROR: incompatible codomain')

        elif isinstance(domain, HPSpace):
            if isinstance(codomain, GLSpace):
                return HPLMTransformation(domain, codomain, module)
            else:
                raise ValueError('ERROR: incompatible codomain')

        elif isinstance(domain, LMSpace):
            if isinstance(codomain, GLSpace):
                return LMGLTransformation(domain, codomain, module)
            elif isinstance(codomain, HPSpace):
                return LMHPTransformation(domain, codomain, module)
            else:
                raise ValueError('ERROR: incompatible codomain')
        else:
            raise ValueError('ERROR: unknown domain')

    def create(self, domain, codomain, module=None):
        key = domain.__hash__() ^ ((codomain.__hash__()/111) ^
                                   (module.__hash__())/179)

        if key not in self.cache:
            self.cache[key] = self._get_transform(domain, codomain, module)

        return self.cache[key]


TransformationFactory = _TransformationFactory()