from __future__ import unicode_literals
from subprocess import (
    call,
    STDOUT
)
from ..version import __version__
import os
import subprocess


def app_version():
    def minimal_env_cmd(cmd):
        # make minimal environment
        env = {k: os.environ[k] for k in ['SYSTEMROOT', 'PATH'] if k in os.environ}
        env.update({'LANGUAGE': 'C', 'LANG': 'C', 'LC_ALL': 'C'})

        out = subprocess.Popen(cmd, stdout=subprocess.PIPE, env=env).communicate()[0]
        return out

    subst_list = {
        "version": __version__,
        "branch": None,
        "commit": None
    }

    if os.system("command -v git > /dev/null 2>&1") != 0:
        return subst_list

    if call(["git", "branch"], stderr=STDOUT, stdout=open(os.devnull, 'w')) != 0:
        return subst_list

    describe = minimal_env_cmd(["git", "describe", "--tags", "--always"])
    git_revision = describe.strip().decode('ascii')

    branch = minimal_env_cmd(["git", "branch"])
    git_branch = branch.strip().decode('ascii').replace('* ', '')

    subst_list.update({
        "branch": git_branch,
        "commit": git_revision
    })

    return subst_list


if __name__ == "__main__":
    app_version()