import contextlib
import os.path
import shutil
import sys

import pytest

from pre_commit import parse_shebang
from pre_commit.envcontext import envcontext
from pre_commit.envcontext import Var
from pre_commit.util import make_executable


def _echo_exe() -> str:
    exe = shutil.which('echo')
    assert exe is not None
    return exe


def test_file_doesnt_exist():
    assert parse_shebang.parse_filename('herp derp derp') == ()


def test_simple_case(tmpdir):
    x = tmpdir.join('f')
    x.write('#!/usr/bin/env echo')
    make_executable(x.strpath)
    assert parse_shebang.parse_filename(x.strpath) == ('echo',)


def test_find_executable_full_path():
    assert parse_shebang.find_executable(sys.executable) == sys.executable


def test_find_executable_on_path():
    assert parse_shebang.find_executable('echo') == _echo_exe()


def test_find_executable_not_found_none():
    assert parse_shebang.find_executable('not-a-real-executable') is None


def write_executable(shebang, filename='run'):
    os.mkdir('bin')
    path = os.path.join('bin', filename)
    with open(path, 'w') as f:
        f.write(f'#!{shebang}')
    make_executable(path)
    return path


@contextlib.contextmanager
def bin_on_path():
    bindir = os.path.join(os.getcwd(), 'bin')
    with envcontext((('PATH', (bindir, os.pathsep, Var('PATH'))),)):
        yield


def test_find_executable_path_added(in_tmpdir):
    path = os.path.abspath(write_executable('/usr/bin/env sh'))
    assert parse_shebang.find_executable('run') is None
    with bin_on_path():
        assert parse_shebang.find_executable('run') == path


def test_find_executable_path_ext(in_tmpdir):
    """Windows exports PATHEXT as a list of extensions to automatically add
    to executables when doing PATH searching.
    """
    exe_path = os.path.abspath(
        write_executable('/usr/bin/env sh', filename='run.myext'),
    )
    env_path = {'PATH': os.path.dirname(exe_path)}
    env_path_ext = dict(env_path, PATHEXT=os.pathsep.join(('.exe', '.myext')))
    assert parse_shebang.find_executable('run') is None
    assert parse_shebang.find_executable('run', _environ=env_path) is None
    ret = parse_shebang.find_executable('run.myext', _environ=env_path)
    assert ret == exe_path
    ret = parse_shebang.find_executable('run', _environ=env_path_ext)
    assert ret == exe_path


def test_normexe_does_not_exist():
    with pytest.raises(OSError) as excinfo:
        parse_shebang.normexe('i-dont-exist-lol')
    assert excinfo.value.args == ('Executable `i-dont-exist-lol` not found',)


def test_normexe_does_not_exist_sep():
    with pytest.raises(OSError) as excinfo:
        parse_shebang.normexe('./i-dont-exist-lol')
    assert excinfo.value.args == ('Executable `./i-dont-exist-lol` not found',)


@pytest.mark.xfail(os.name == 'nt', reason='posix only')
def test_normexe_not_executable(tmpdir):  # pragma: win32 no cover
    tmpdir.join('exe').ensure()
    with tmpdir.as_cwd(), pytest.raises(OSError) as excinfo:
        parse_shebang.normexe('./exe')
    assert excinfo.value.args == ('Executable `./exe` is not executable',)


def test_normexe_is_a_directory(tmpdir):
    with tmpdir.as_cwd():
        tmpdir.join('exe').ensure_dir()
        exe = os.path.join('.', 'exe')
        with pytest.raises(OSError) as excinfo:
            parse_shebang.normexe(exe)
        msg, = excinfo.value.args
        assert msg == f'Executable `{exe}` is a directory'


def test_normexe_already_full_path():
    assert parse_shebang.normexe(sys.executable) == sys.executable


def test_normexe_gives_full_path():
    assert parse_shebang.normexe('echo') == _echo_exe()
    assert os.sep in _echo_exe()


def test_normalize_cmd_trivial():
    cmd = (_echo_exe(), 'hi')
    assert parse_shebang.normalize_cmd(cmd) == cmd


def test_normalize_cmd_PATH():
    cmd = ('echo', '--version')
    expected = (_echo_exe(), '--version')
    assert parse_shebang.normalize_cmd(cmd) == expected


def test_normalize_cmd_shebang(in_tmpdir):
    echo = _echo_exe().replace(os.sep, '/')
    path = write_executable(echo)
    assert parse_shebang.normalize_cmd((path,)) == (echo, path)


def test_normalize_cmd_PATH_shebang_full_path(in_tmpdir):
    echo = _echo_exe().replace(os.sep, '/')
    path = write_executable(echo)
    with bin_on_path():
        ret = parse_shebang.normalize_cmd(('run',))
        assert ret == (echo, os.path.abspath(path))


def test_normalize_cmd_PATH_shebang_PATH(in_tmpdir):
    echo = _echo_exe()
    path = write_executable('/usr/bin/env echo')
    with bin_on_path():
        ret = parse_shebang.normalize_cmd(('run',))
        assert ret == (echo, os.path.abspath(path))