from subprocess import Popen, PIPE
import os
import sys

pyver = sys.version_info


# ----------------------------------------------------------------------------
# Get version string from git
#
# Author: Douglas Creager <dcreager@dcreager.net>
# http://dcreager.net/2010/02/10/setuptools-git-version-numbers/
#
# PEP 386 adaptation from
# https://gist.github.com/ilogue/2567778/f6661ea2c12c070851b2dfb4da8840a6641914bc
# ----------------------------------------------------------------------------
def call_git_describe(abbrev=4):
    try:
        p = Popen(['git', 'describe', '--exclude', 'ev3dev-*', '--abbrev=%d' % abbrev], stdout=PIPE, stderr=PIPE)
        p.stderr.close()
        line = p.stdout.readlines()[0]
        return line.strip().decode('utf8')

    except Exception:
        return None


def read_release_version():
    try:
        with open('{}/RELEASE-VERSION'.format(os.path.dirname(__file__)), 'r') as f:
            version = f.readlines()[0]
            return version.strip()
    except Exception:
        return None


def write_release_version(version):
    with open('{}/RELEASE-VERSION'.format(os.path.dirname(__file__)), 'w') as f:
        f.write("%s\n" % version)


def pep386adapt(version):
    # adapt git-describe version to be in line with PEP 386
    parts = version.split('-')
    if len(parts) > 1:
        parts[-2] = 'post' + parts[-2]
        version = '.'.join(parts[:-1])
    return version


def git_version(abbrev=4):
    # Read in the version that's currently in RELEASE-VERSION.
    release_version = read_release_version()

    # Try to get the current version using "git describe".
    version = call_git_describe(abbrev)

    # If that doesn't work, fall back on the value that's in
    # RELEASE-VERSION.
    if version is None:
        version = release_version
    else:
        # adapt to PEP 386 compatible versioning scheme
        version = pep386adapt(version)

    # If we still don't have anything, that's an error.
    if version is None:
        raise ValueError("Cannot find the version number!")

    # If the current version is different from what's in the
    # RELEASE-VERSION file, update the file to be current.
    if version != release_version:
        write_release_version(version)

    # Update the ev3dev2/version.py
    with open('{}/ev3dev2/version.py'.format(os.path.dirname(__file__)), 'w') as f:
        f.write("__version__ = '{}'".format(version))

    # Finally, return the current version.
    return version
