#   Copyright 2015 Ufora Inc.
#
#   Licensed under the Apache License, Version 2.0 (the "License");
#   you may not use this file except in compliance with the License.
#   You may obtain a copy of the License at
#
#       http://www.apache.org/licenses/LICENSE-2.0
#
#   Unless required by applicable law or agreed to in writing, software
#   distributed under the License is distributed on an "AS IS" BASIS,
#   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
#   See the License for the specific language governing permissions and
#   limitations under the License.

from pyfora.Exceptions import PythonToForaConversionError

import ufora.native.FORA as ForaNative


class ConstantConverter(object):
    def __init__(self, nativeConstantConverter=None):
        self.conversionDict = \
            ConstantConverter.createConversionDict(nativeConstantConverter)

        self.nativeConstantConverter = nativeConstantConverter

    @staticmethod
    def createConversionDict(nativeConstantConverter):
        return {
            int: nativeConstantConverter.convertInt,
            long: nativeConstantConverter.convertLong,
            bool: nativeConstantConverter.convertBool,
            float: nativeConstantConverter.convertFloat,
            str: nativeConstantConverter.convertString,
            type(None): lambda _: nativeConstantConverter.noneValue()
            }

    def convert(self, pyObject):
        if type(pyObject) in self.conversionDict:
            return self.conversionDict[type(pyObject)](pyObject)
        else:
            raise PythonToForaConversionError("can't convert " + str(pyObject))

    def invertForaConstant(self, implVal):
        """attempt to unwrap the ForaValue as a constant (returning it in a tuple),
        or return None if we can't unwrap it.
        """
        return self.nativeConstantConverter.invertForaConstant(implVal)


