from __future__ import unicode_literals

import contextlib

from pre_commit.languages import helpers
from pre_commit.prefixed_command_runner import CalledProcessError
from pre_commit.util import clean_path_on_failure


ENVIRONMENT_DIR = 'node_env'


class NodeEnv(helpers.Environment):
    @property
    def env_prefix(self):
        return '. {{prefix}}{0}/bin/activate &&'.format(ENVIRONMENT_DIR)


@contextlib.contextmanager
def in_env(repo_cmd_runner):
    yield NodeEnv(repo_cmd_runner)


def install_environment(repo_cmd_runner, version='default'):
    assert repo_cmd_runner.exists('package.json')

    env_dir = repo_cmd_runner.path(ENVIRONMENT_DIR)
    with clean_path_on_failure(env_dir):
        if version == 'default':
            # In the default case we attempt to install system node and if that
            # doesn't work we use --prebuilt
            try:
                with clean_path_on_failure(env_dir):
                    repo_cmd_runner.run([
                        'python', '-m', 'nodeenv', '-n', 'system',
                        '{{prefix}}{0}'.format(ENVIRONMENT_DIR),
                    ])
            except CalledProcessError:
                # TODO: log failure here
                repo_cmd_runner.run([
                    'python', '-m', 'nodeenv', '--prebuilt',
                    '{{prefix}}{0}'.format(ENVIRONMENT_DIR)
                ])
        else:
            repo_cmd_runner.run([
                'python', '-m', 'nodeenv', '--prebuilt', '-n', version,
                '{{prefix}}{0}'.format(ENVIRONMENT_DIR)
            ])

        with in_env(repo_cmd_runner) as node_env:
            node_env.run('cd {prefix} && npm install -g')


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)