from __future__ import absolute_import
# Copyright (c) 2010-2015 openpyxl

from openpyxl.utils.indexed_list import IndexedList

from .numbers import BUILTIN_FORMATS, BUILTIN_FORMATS_REVERSE


class StyleProxy(object):
    """
    Proxy formatting objects so that they cannot be altered
    """

    __slots__ = ('__target')

    def __init__(self, target):
        if not hasattr(target, 'copy'):
            raise TypeError("Proxied objects must have a copy method.")
        self.__target = target


    def __repr__(self):
        return repr(self.__target)


    def __getattr__(self, attr):
        return getattr(self.__target, attr)


    def __setattr__(self, attr, value):
        if attr != "_StyleProxy__target":
            raise AttributeError("Style objects are immutable and cannot be changed."
                                 "Reassign the style with a copy")
        super(StyleProxy, self).__setattr__(attr, value)


    def copy(self, **kw):
        """Return a copy of the proxied object. Keyword args will be passed through"""
        return self.__target.copy(**kw)


    def __eq__(self, other):
        return self.__target == other


    def __ne__(self, other):
        return not self == other