from __future__ import unicode_literals

import contextlib
import os

from pre_commit.envcontext import envcontext
from pre_commit.envcontext import Var
from pre_commit.languages import helpers
from pre_commit.util import clean_path_on_failure
from pre_commit.util import cmd_output
from pre_commit.xargs import xargs

ENVIRONMENT_DIR = 'swift_env'
get_default_version = helpers.basic_get_default_version
healthy = helpers.basic_healthy
BUILD_DIR = '.build'
BUILD_CONFIG = 'release'


def get_env_patch(venv):  # pragma: windows no cover
    bin_path = os.path.join(venv, BUILD_DIR, BUILD_CONFIG)
    return (('PATH', (bin_path, os.pathsep, Var('PATH'))),)


@contextlib.contextmanager
def in_env(prefix):  # pragma: windows no cover
    envdir = prefix.path(
        helpers.environment_dir(ENVIRONMENT_DIR, 'default'),
    )
    with envcontext(get_env_patch(envdir)):
        yield


def install_environment(
        prefix, version, additional_dependencies,
):  # pragma: windows no cover
    helpers.assert_version_default('swift', version)
    helpers.assert_no_additional_deps('swift', additional_dependencies)
    directory = prefix.path(
        helpers.environment_dir(ENVIRONMENT_DIR, 'default'),
    )

    # Build the swift package
    with clean_path_on_failure(directory):
        os.mkdir(directory)
        cmd_output(
            'swift', 'build',
            '-C', prefix.prefix_dir,
            '-c', BUILD_CONFIG,
            '--build-path', os.path.join(directory, BUILD_DIR),
        )


def run_hook(prefix, hook, file_args):  # pragma: windows no cover
    with in_env(prefix):
        return xargs(helpers.to_cmd(hook), file_args)