# This file is dual licensed under the terms of the Apache License, Version
# 2.0, and the BSD License. See the LICENSE file in the root of this repository
# for complete details.
from __future__ import absolute_import, division, print_function

import re

from ._typing import TYPE_CHECKING, cast
from .version import InvalidVersion, Version

if TYPE_CHECKING:  # pragma: no cover
    from typing import NewType, Union

    NormalizedName = NewType("NormalizedName", str)
else:
    NormalizedName = str

_canonicalize_regex = re.compile(r"[-_.]+")


def canonicalize_name(name):
    # type: (str) -> NormalizedName
    # This is taken from PEP 503.
    value = _canonicalize_regex.sub("-", name).lower()
    return cast("NormalizedName", value)


def canonicalize_version(version):
    # type: (Union[Version, str]) -> Union[Version, str]
    """
    This is very similar to Version.__str__, but has one subtle difference
    with the way it handles the release segment.
    """
    if not isinstance(version, Version):
        try:
            version = Version(version)
        except InvalidVersion:
            # Legacy versions cannot be normalized
            return version

    parts = []

    # Epoch
    if version.epoch != 0:
        parts.append("{0}!".format(version.epoch))

    # Release segment
    # NB: This strips trailing '.0's to normalize
    parts.append(re.sub(r"(\.0)+$", "", ".".join(str(x) for x in version.release)))

    # Pre-release
    if version.pre is not None:
        parts.append("".join(str(x) for x in version.pre))

    # Post-release
    if version.post is not None:
        parts.append(".post{0}".format(version.post))

    # Development release
    if version.dev is not None:
        parts.append(".dev{0}".format(version.dev))

    # Local version segment
    if version.local is not None:
        parts.append("+{0}".format(version.local))

    return "".join(parts)
