#------------------------------------------------------------------------------
# Copyright (c) 2013-2017, Nucleic Development Team.
#
# Distributed under the terms of the Modified BSD License.
#
# The full license is in the file LICENSE, distributed with this software.
#------------------------------------------------------------------------------
# Note: This module is imported by 'atom.catom' module from code defined in
# the 'enumtypes.cpp' file. This module must therefore not import atom.
import copyreg


# IntEnum is not defined until the metaclass creates it.
IntEnum = None


def _invalid_op(op):
    msg = " is an invalid operation for {}"
    msg = ("'%s'" % op) + msg

    def closure(self, *args):
        # Use format as otherwise fail for mod operator
        raise TypeError(msg.format(self))

    return closure


def _int_enum_flags_unpickler(enum_class, value):
    return int.__new__(enum_class.Flags, value)


def _int_enum_flags_pickler(flags):
    enum_class = type(flags).__enum_class__
    return _int_enum_flags_unpickler, (enum_class, int(flags))


class _IntEnumMeta(type):
    """ The metaclass for IntEnum and its subclasses.

    """
    class IntEnumFlags(int):

        # Set by the metaclass in the Flags property.
        __enum_class__ = None

        def __new__(cls, value=0):
            if isinstance(value, cls):
                return value
            if value == 0:
                return int.__new__(cls, value)
            return int.__new__(cls, cls.__enum_class__(value))

        def __make_flags(self, other, value):
            scls = type(self)
            ocls = type(other)
            if ocls is not scls and ocls is not scls.__enum_class__:
                msg = "cannot combine %s with object of type '%s'"
                raise TypeError(msg % (self, ocls.__name__))
            return int.__new__(scls, value)

        def __repr__(self):
            return '<enumflags: %s [value=%d]>' % (type(self).__name__, self)

        def __str__(self):
            return type(self).__name__

        def __and__(self, other):
            return self.__make_flags(other, int.__and__(self, other))

        __rand__ = __and__

        def __or__(self, other):
            return self.__make_flags(other, int.__or__(self, other))

        __ror__ = __or__

        def __xor__(self, other):
            return self.__make_flags(other, int.__xor__(self, other))

        __rxor__ = __xor__

        def __invert__(self):
            return self.__make_flags(self, int.__invert__(self))

        __add__ = _invalid_op('+')
        __sub__ = _invalid_op('-')
        __mul__ = _invalid_op('*')
        __div__ = _invalid_op('/')
        __truediv__ = _invalid_op('/')
        __floordiv__ = _invalid_op('//')
        __mod__ = _invalid_op('%')
        __divmod__ = _invalid_op('divmod')
        __pow__ = _invalid_op('**')
        __lshift__ = _invalid_op('<<')
        __rshift__ = _invalid_op('>>')
        __radd__ = _invalid_op('+')
        __rsub__ = _invalid_op('-')
        __rmul__ = _invalid_op('*')
        __rdiv__ = _invalid_op('/')
        __rtruediv__ = _invalid_op('/')
        __rfloordiv__ = _invalid_op('//')
        __rmod__ = _invalid_op('%')
        __rdivmod__ = _invalid_op('divmod')
        __rpow__ = _invalid_op('**')
        __rlshift__ = _invalid_op('<<')
        __rrshift__ = _invalid_op('>>')
        __neg__ = _invalid_op('-')
        __pos__ = _invalid_op('+')
        __abs__ = _invalid_op('abs')

    def __new__(meta, name, bases, dct):
        if len(bases) > 1:
            raise TypeError('int enums do not support multiple inheritance')
        if IntEnum is None:
            return type.__new__(meta, name, bases, dct)
        if bases[0] is not IntEnum:
            raise TypeError('int enums cannot be extended')
        enums = {}
        reved = {}
        cls = type.__new__(meta, name, bases, dct)
        for key, value in cls.__dict__.items():
            if isinstance(value, int):
                enum = int.__new__(cls, value)
                enum.__enum_name__ = key
                type.__setattr__(cls, key, enum)
                enums[key] = enum
                reved[int(enum)] = enum
        type.__setattr__(cls, '__enums__', enums)
        type.__setattr__(cls, '__reved__', reved)
        return cls

    def __call__(cls, which):
        enum = None
        if isinstance(which, int):
            enum = cls.__reved__.get(which)
        elif isinstance(which, str):
            enum = cls.__enums__.get(which)
        else:
            msg = "enum specifier must be an int or str, "
            msg += "got object of type '%s' instead"
            raise TypeError(msg % type(which).__name__)
        if enum is None:
            msg = "'%s' is not a valid %s enum specifier"
            raise ValueError(msg % (which, cls.__name__))
        return enum

    def __contains__(cls, which):
        return which in cls.__reved__ or which in cls.__enums__

    def __getitem__(cls, which):
        return cls(which)

    def __len__(cls):
        return len(cls.__enums__)

    def __iter__(cls):
        return iter(cls.__enums__.values())

    def __setattr__(cls, name, value):
        if name in cls.__enums__:
            raise TypeError("cannot change the value of an enum")
        type.__setattr__(cls, name, value)

    @property
    def Flags(cls):
        if cls.__flags_class__ is not None:
            return cls.__flags_class__
        name = cls.__name__ + 'Flags'
        flags_class = type(name, (cls.IntEnumFlags,), {})
        flags_class.__enum_class__ = cls
        cls.__flags_class__ = flags_class
        copyreg.pickle(flags_class, _int_enum_flags_pickler)
        return flags_class


class IntEnum(int, metaclass=_IntEnumMeta):
    """ An integer subclass for declaring enum types.

    """

    # Set by the metaclass in the Flags property.
    __flags_class__ = None

    def __make_flags(self, other, value):
        scls = type(self)
        ocls = type(other)
        fcls = scls.Flags
        if ocls is not scls and ocls is not fcls:
            msg = "cannot combine %s with object of type '%s'"
            raise TypeError(msg % (self, ocls.__name__))
        return int.__new__(fcls, value)

    def __reduce_ex__(self, proto):
        return (type(self), (int(self),))

    def __repr__(self):
        t_name = type(self).__name__
        s_name = self.__enum_name__
        return '<enum: %s.%s [value=%d]>' % (t_name, s_name, self)

    def __str__(self):
        return '%s.%s' % (type(self).__name__, self.__enum_name__)

    def __and__(self, other):
        return self.__make_flags(other, int.__and__(self, other))

    __rand__ = __and__

    def __or__(self, other):
        return self.__make_flags(other, int.__or__(self, other))

    __ror__ = __or__

    def __xor__(self, other):
        return self.__make_flags(other, int.__xor__(self, other))

    __rxor__ = __xor__

    def __invert__(self):
        return self.__make_flags(self, int.__invert__(self))

    __add__ = _invalid_op('+')
    __sub__ = _invalid_op('-')
    __mul__ = _invalid_op('*')
    __div__ = _invalid_op('/')
    __truediv__ = _invalid_op('/')
    __floordiv__ = _invalid_op('//')
    __mod__ = _invalid_op('%')
    __divmod__ = _invalid_op('divmod')
    __pow__ = _invalid_op('**')
    __lshift__ = _invalid_op('<<')
    __rshift__ = _invalid_op('>>')
    __radd__ = _invalid_op('+')
    __rsub__ = _invalid_op('-')
    __rmul__ = _invalid_op('*')
    __rdiv__ = _invalid_op('/')
    __rtruediv__ = _invalid_op('/')
    __rfloordiv__ = _invalid_op('//')
    __rmod__ = _invalid_op('%')
    __rdivmod__ = _invalid_op('divmod')
    __rpow__ = _invalid_op('**')
    __rlshift__ = _invalid_op('<<')
    __rrshift__ = _invalid_op('>>')
    __neg__ = _invalid_op('-')
    __pos__ = _invalid_op('+')
    __abs__ = _invalid_op('abs')

    @property
    def name(self):
        return self.__enum_name__
