""" Utilities for using virtualenv as library and planemo command.
"""
from __future__ import absolute_import

import os
import sys

from galaxy.util.commands import which

DEFAULT_PYTHON_VERSION = os.environ.get("PLANEMO_DEFAULT_PYTHON_VERSION", "3")


def create_command(virtualenv_path, galaxy_python_version=None):
    """ If virtualenv is on Planemo's path use it, otherwise use the planemo
    subcommand virtualenv to create the virtualenv.
    """
    # Create a virtualenv with the selected python version.
    if galaxy_python_version is None:
        galaxy_python_version = DEFAULT_PYTHON_VERSION
    python = which("python%s" % galaxy_python_version)
    if python:
        python = os.path.abspath(python)
    else:
        python = sys.executable or 'python'
    command = [python, '-m', 'venv', virtualenv_path]
    return " ".join(command)