# Copyright 2013-2019 Lawrence Livermore National Security, LLC and other
# Spack Project Developers. See the top-level COPYRIGHT file for details.
#
# SPDX-License-Identifier: (Apache-2.0 OR MIT)

"""Test Spack's environment utility functions."""
import pytest
import os
import spack.util.environment as envutil


@pytest.fixture()
def prepare_environment_for_tests():
    if 'TEST_ENV_VAR' in os.environ:
        del os.environ['TEST_ENV_VAR']
    yield
    del os.environ['TEST_ENV_VAR']


def test_is_system_path():
    assert(envutil.is_system_path('/usr/bin'))
    assert(not envutil.is_system_path('/nonsense_path/bin'))


test_paths = ['/usr/bin',
              '/nonsense_path/lib',
              '/usr/local/lib',
              '/bin',
              '/nonsense_path/extra/bin',
              '/usr/lib64']


def test_filter_system_paths():
    expected = [p for p in test_paths if p.startswith('/nonsense_path')]
    filtered = envutil.filter_system_paths(test_paths)
    assert(expected == filtered)


def deprioritize_system_paths():
    expected = [p for p in test_paths if p.startswith('/nonsense_path')]
    expected.extend([p for p in test_paths
                     if not p.startswith('/nonsense_path')])
    filtered = envutil.deprioritize_system_paths(test_paths)
    assert(expected == filtered)


def test_prune_duplicate_paths():
    test_paths = ['/a/b', '/a/c', '/a/b', '/a/a', '/a/c', '/a/a/..']
    expected = ['/a/b', '/a/c', '/a/a', '/a/a/..']
    assert(expected == envutil.prune_duplicate_paths(test_paths))


def test_get_path(prepare_environment_for_tests):
    os.environ['TEST_ENV_VAR'] = '/a:/b:/c/d'
    expected = ['/a', '/b', '/c/d']
    assert(envutil.get_path('TEST_ENV_VAR') == expected)


def test_env_flag(prepare_environment_for_tests):
    assert(not envutil.env_flag('TEST_NO_ENV_VAR'))
    os.environ['TEST_ENV_VAR'] = '1'
    assert(envutil.env_flag('TEST_ENV_VAR'))
    os.environ['TEST_ENV_VAR'] = 'TRUE'
    assert(envutil.env_flag('TEST_ENV_VAR'))
    os.environ['TEST_ENV_VAR'] = 'True'
    assert(envutil.env_flag('TEST_ENV_VAR'))
    os.environ['TEST_ENV_VAR'] = 'TRue'
    assert(envutil.env_flag('TEST_ENV_VAR'))
    os.environ['TEST_ENV_VAR'] = 'true'
    assert(envutil.env_flag('TEST_ENV_VAR'))
    os.environ['TEST_ENV_VAR'] = '27'
    assert(not envutil.env_flag('TEST_ENV_VAR'))
    os.environ['TEST_ENV_VAR'] = '-2.3'
    assert(not envutil.env_flag('TEST_ENV_VAR'))
    os.environ['TEST_ENV_VAR'] = '0'
    assert(not envutil.env_flag('TEST_ENV_VAR'))
    os.environ['TEST_ENV_VAR'] = 'False'
    assert(not envutil.env_flag('TEST_ENV_VAR'))
    os.environ['TEST_ENV_VAR'] = 'false'
    assert(not envutil.env_flag('TEST_ENV_VAR'))
    os.environ['TEST_ENV_VAR'] = 'garbage'
    assert(not envutil.env_flag('TEST_ENV_VAR'))


def test_path_set(prepare_environment_for_tests):
    envutil.path_set('TEST_ENV_VAR', ['/a', '/a/b', '/a/a'])
    assert(os.environ['TEST_ENV_VAR'] == '/a:/a/b:/a/a')


def test_path_put_first(prepare_environment_for_tests):
    envutil.path_set('TEST_ENV_VAR', test_paths)
    expected = ['/usr/bin', '/new_nonsense_path/a/b']
    expected.extend([p for p in test_paths if p != '/usr/bin'])
    envutil.path_put_first('TEST_ENV_VAR', expected)
    assert(envutil.get_path('TEST_ENV_VAR') == expected)


def test_dump_environment(prepare_environment_for_tests, tmpdir):
    test_paths = '/a:/b/x:/b/c'
    os.environ['TEST_ENV_VAR'] = test_paths
    dumpfile_path = str(tmpdir.join('envdump.txt'))
    envutil.dump_environment(dumpfile_path)
    with open(dumpfile_path, 'r') as dumpfile:
        assert('TEST_ENV_VAR={0}; export TEST_ENV_VAR\n'.format(test_paths)
               in list(dumpfile))


def test_reverse_environment_modifications(working_env):
    start_env = {
        'PREPEND_PATH': '/path/to/prepend/to',
        'APPEND_PATH': '/path/to/append/to',
        'UNSET': 'var_to_unset',
        'APPEND_FLAGS': 'flags to append to',
    }

    to_reverse = envutil.EnvironmentModifications()

    to_reverse.prepend_path('PREPEND_PATH', '/new/path/prepended')
    to_reverse.append_path('APPEND_PATH', '/new/path/appended')
    to_reverse.set_path('SET_PATH', ['/one/set/path', '/two/set/path'])
    to_reverse.set('SET', 'a var')
    to_reverse.unset('UNSET')
    to_reverse.append_flags('APPEND_FLAGS', 'more_flags')

    reversal = to_reverse.reversed()

    os.environ = start_env.copy()

    print(os.environ)
    to_reverse.apply_modifications()
    print(os.environ)
    reversal.apply_modifications()
    print(os.environ)

    start_env.pop('UNSET')
    assert os.environ == start_env
