# -*- coding: utf-8 -*-
# This file is part of 'miniver': https://github.com/jbweston/miniver
#
from collections import namedtuple
import os
import subprocess
import sys

from distutils.command.build_py import build_py as build_py_orig
from setuptools.command.sdist import sdist as sdist_orig

Version = namedtuple('Version', ('release', 'dev', 'labels'))

# No public API
__all__ = []

package_root = os.path.dirname(os.path.realpath(__file__))
package_name = os.path.basename(package_root)
distr_root = os.path.dirname(package_root)

STATIC_VERSION_FILE = '_static_version.py'


def get_version(version_file=STATIC_VERSION_FILE):
    version_info = {}
    with open(os.path.join(package_root, version_file), 'rb') as f:
        exec(f.read(), {}, version_info)
    version = version_info['version']
    if version == "__use_git__":
        version = get_version_from_git()
        if not version:
            version = get_version_from_git_archive(version_info)
        if not version:
            version = Version("unknown", None, None)
        return pep440_format(version)
    else:
        return version


def pep440_format(version_info):
    release, dev, labels = version_info

    version_parts = [release]
    if dev:
        if release.endswith('-dev') or release.endswith('.dev'):
            version_parts.append(dev)
        else:  # prefer PEP440 over stric adhesion to semver
            version_parts.append('.dev{}'.format(dev))

    if labels:
        version_parts.append('+')
        version_parts.append(".".join(labels))

    return "".join(version_parts)


def get_version_from_git():
    try:
        p = subprocess.Popen(['git', 'rev-parse', '--show-toplevel'],
                             cwd=distr_root,
                             stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    except OSError:
        return
    if p.wait() != 0:
        return
    if not os.path.samefile(p.communicate()[0].decode().rstrip('\n'),
                            distr_root):
        # The top-level directory of the current Git repository is not the same
        # as the root directory of the distribution: do not extract the
        # version from Git.
        return

    # git describe --first-parent does not take into account tags from branches
    # that were merged-in.
    for opts in [['--first-parent'], []]:
        try:
            p = subprocess.Popen(['git', 'describe', '--long'] + opts,
                                 cwd=distr_root,
                                 stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        except OSError:
            return
        if p.wait() == 0:
            break
    else:
        return
    description = p.communicate()[0].decode().strip('v').rstrip('\n')

    release, dev, git = description.rsplit('-', 2)
    labels = []
    if dev == "0":
        dev = None
    else:
        labels.append(git)

    try:
        p = subprocess.Popen(['git', 'diff', '--quiet'], cwd=distr_root)
    except OSError:
        labels.append('confused') # This should never happen.
    else:
        if p.wait() == 1:
            labels.append('dirty')

    return Version(release, dev, labels)


# TODO: change this logic when there is a git pretty-format
#       that gives the same output as 'git describe'.
#       Currently we can only tell the tag the current commit is
#       pointing to, or its hash (with no version info)
#       if it is not tagged.
def get_version_from_git_archive(version_info):
    try:
        refnames = version_info['refnames']
        git_hash = version_info['git_hash']
    except KeyError:
        # These fields are not present if we are running from an sdist.
        # Execution should never reach here, though
        return None

    if git_hash.startswith('$Format') or refnames.startswith('$Format'):
        # variables not expanded during 'git archive'
        return None

    VTAG = 'tag: v'
    refs = set(r.strip() for r in refnames.split(","))
    version_tags = set(r[len(VTAG):] for r in refs if r.startswith(VTAG))
    if version_tags:
        release, *_ = sorted(version_tags)  # prefer e.g. "2.0" over "2.0rc1"
        return Version(release, dev=None, labels=None)
    else:
        return Version('unknown', dev=None, labels=['g{}'.format(git_hash)])


__version__ = get_version()

# The following section defines a module global 'cmdclass',
# which can be used from setup.py. The 'package_name' and
# '__version__' module globals are used (but not modified).

def _write_version(fname):
    # This could be a hard link, so try to delete it first.  Is there any way
    # to do this atomically together with opening?
    try:
        os.remove(fname)
    except OSError:
        pass
    with open(fname, 'w') as f:
        f.write("# This file has been created by setup.py.\n"
                "version = '{}'\n".format(__version__))


class _build_py(build_py_orig):
    def run(self):
        super().run()
        _write_version(os.path.join(self.build_lib, package_name,
                                    STATIC_VERSION_FILE))


class _sdist(sdist_orig):
    def make_release_tree(self, base_dir, files):
        super().make_release_tree(base_dir, files)
        _write_version(os.path.join(base_dir, package_name,
                                    STATIC_VERSION_FILE))


cmdclass = dict(sdist=_sdist, build_py=_build_py)
