from __future__ import unicode_literals

import contextlib

from pre_commit.languages import helpers

from pre_commit.util import clean_path_on_failure

ENVIRONMENT_DIR = 'py_env'

class PythonEnv(helpers.Environment):

@property

def env_prefix(self):

return '. {{prefix}}{0}/bin/activate &&'.format(ENVIRONMENT_DIR)

@contextlib.contextmanager

def in_env(repo_cmd_runner):

yield PythonEnv(repo_cmd_runner)

def install_environment(repo_cmd_runner, version='default'):

assert repo_cmd_runner.exists('setup.py')

# Install a virtualenv

with clean_path_on_failure(repo_cmd_runner.path(ENVIRONMENT_DIR)):

venv_cmd = ['virtualenv', '{{prefix}}{0}'.format(ENVIRONMENT_DIR)]

if version != 'default':

venv_cmd.extend(['-p', version])

repo_cmd_runner.run(venv_cmd)

with in_env(repo_cmd_runner) as env:

env.run('cd {prefix} && pip install .')

def run_hook(repo_cmd_runner, hook, file_args):

with in_env(repo_cmd_runner) as env:

return helpers.run_hook(env, hook, file_args)