# -*- coding: utf-8 -*-

# This code is part of Qiskit.
#
# (C) Copyright IBM 2019.
#
# This code is licensed under the Apache License, Version 2.0. You may
# obtain a copy of this license in the LICENSE.txt file in the root directory
# of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
#
# Any modifications or derivative works of this code must retain this
# copyright notice, and modified files need to carry a notice indicating
# that they have been altered from the originals.

"""Functions for getting version information about ignis."""


import os
import subprocess

ROOT_DIR = os.path.dirname(os.path.abspath(__file__))


def _minimal_ext_cmd(cmd):
    # construct minimal environment
    env = {}
    for k in ['SYSTEMROOT', 'PATH']:
        v = os.environ.get(k)
        if v is not None:
            env[k] = v
    # LANGUAGE is used on win32
    env['LANGUAGE'] = 'C'
    env['LANG'] = 'C'
    env['LC_ALL'] = 'C'
    proc = subprocess.Popen(cmd, stdout=subprocess.PIPE,
                            stderr=subprocess.PIPE, env=env,
                            cwd=os.path.join(os.path.dirname(ROOT_DIR)))
    out = proc.communicate()[0]
    if proc.returncode > 0:
        raise OSError
    return out


def git_version():
    """Get the current git head sha1."""
    # Determine if we're at master
    try:
        out = _minimal_ext_cmd(['git', 'rev-parse', 'HEAD'])
        git_revision = out.strip().decode('ascii')
    except OSError:
        git_revision = "Unknown"

    return git_revision


with open(os.path.join(ROOT_DIR, "VERSION.txt"), "r") as version_file:
    VERSION = version_file.read().strip()


def get_version_info():
    """Get the full version string."""
    # Adding the git rev number needs to be done inside
    # write_version_py(), otherwise the import of scipy.version messes
    # up the build under Python 3.
    full_version = VERSION

    if not os.path.exists(os.path.join(os.path.dirname(
            os.path.dirname(ROOT_DIR)), '.git')):
        return full_version
    try:
        release = _minimal_ext_cmd(['git', 'tag', '-l', '--points-at', 'HEAD'])
    except Exception:  # pylint: disable=broad-except
        return full_version
    if not release:
        git_revision = git_version()
        full_version += '.dev0+' + git_revision[:7]

    return full_version


__version__ = get_version_info()
