import os
import builtins

import pytest

from xonsh.commands_cache import (CommandsCache, predict_shell,
                                  SHELL_PREDICTOR_PARSER, predict_true, predict_false)
from tools import skip_if_on_windows

def test_commands_cache_lazy(xonsh_builtins):
    cc = CommandsCache()
    assert not cc.lazyin('xonsh')
    assert 0 == len(list(cc.lazyiter()))
    assert 0 == cc.lazylen()


TRUE_SHELL_ARGS = [
    ['-c', 'yo'],
    ['-c=yo'],
    ['file'],
    ['-i', '-l', 'file'],
    ['-i', '-c', 'yo'],
    ['-i', 'file'],
    ['-i', '-c', 'yo', 'file'],
    ]

@pytest.mark.parametrize('args', TRUE_SHELL_ARGS)
def test_predict_shell_parser(args):
    ns, unknown = SHELL_PREDICTOR_PARSER.parse_known_args(args)
    if ns.filename is not None:
        assert not ns.filename.startswith('-')


@pytest.mark.parametrize('args', TRUE_SHELL_ARGS)
def test_predict_shell_true(args):
    assert predict_shell(args)


FALSE_SHELL_ARGS = [
    [],
    ['-c'],
    ['-i'],
    ['-i', '-l'],
    ]

@pytest.mark.parametrize('args', FALSE_SHELL_ARGS)
def test_predict_shell_false(args):
    assert not predict_shell(args)


PATTERN_BIN_USING_TTY_OR_NOT = [
    (False, {10: b'isnotatty'}),
    (False, {12: b'isatty'}),
    (False, {151: b'gpm'}),
    (False, {10: b'isatty', 100: b'tcgetattr', }),
    (False, {10: b'isatty', 100: b'tcsetattr'}),
    (True, {10: b'isatty', 100: b'tcsetattr', 1000: b'tcgetattr'}),
    (True, {1000: b'libncurses'}),
    (True, {4094: b'libgpm'}),
    (True, {2045: b'tcgetattr', 4095: b'tcgetattr', 6140: b'tcsetattr',
            8190: b'isatty'}),
]


@pytest.mark.parametrize('args', PATTERN_BIN_USING_TTY_OR_NOT)
@skip_if_on_windows
def test_commands_cache_predictor_default(args):
    cc = CommandsCache()
    use_tty, patterns = args
    f = open('testfile', 'wb')
    where = list(patterns.keys())
    where.sort()

    pos = 0
    for w in where:
        f.write(b'\x20' * (w - pos))
        f.write(patterns[w])
        pos = w + len(patterns[w])

    f.write(b'\x20' * (pos // 2))
    f.close()

    result = cc.default_predictor_readbin('', os.getcwd() + os.sep + 'testfile',
                                          timeout=1, failure=None)
    expected = predict_false if use_tty else predict_true
    assert result == expected


@skip_if_on_windows
def test_cd_is_only_functional_alias(xonsh_builtins):
    cc = CommandsCache()
    builtins.aliases['cd'] = lambda args: os.chdir(args[0])
    assert cc.is_only_functional_alias('cd')


def test_non_exist_is_only_functional_alias(xonsh_builtins):
    cc = CommandsCache()
    assert not cc.is_only_functional_alias('<not really a command name>')


@skip_if_on_windows
def test_bash_is_only_functional_alias(xonsh_builtins):
    builtins.__xonsh_env__['PATH'] = os.environ['PATH'].split(os.pathsep)
    cc = CommandsCache()
    assert not cc.is_only_functional_alias('bash')


@skip_if_on_windows
def test_bash_and_is_alias_is_only_functional_alias(xonsh_builtins):
    builtins.__xonsh_env__['PATH'] = os.environ['PATH'].split(os.pathsep)
    cc = CommandsCache()
    builtins.aliases['bash'] = lambda args: os.chdir(args[0])
    assert not cc.is_only_functional_alias('bash')