import os
import tempfile
import unittest

import pytest

from ..platform.xattr import buffer, split_lstring
from ..xattr import is_enabled, getxattr, setxattr, listxattr
from ..platformflags import is_linux
from . import BaseTestCase


@unittest.skipUnless(is_enabled(), 'xattr not enabled on filesystem')
class XattrTestCase(BaseTestCase):

    def setUp(self):
        self.tmpfile = tempfile.NamedTemporaryFile()
        self.symlink = self.tmpfile.name + '.symlink'
        os.symlink(self.tmpfile.name, self.symlink)

    def tearDown(self):
        os.unlink(self.symlink)

    def assert_equal_se(self, is_x, want_x):
        # check 2 xattr lists for equality, but ignore security.selinux attr
        is_x = set(is_x) - {b'security.selinux'}
        want_x = set(want_x)
        self.assert_equal(is_x, want_x)

    def test(self):
        tmp_fn = os.fsencode(self.tmpfile.name)
        tmp_lfn = os.fsencode(self.symlink)
        tmp_fd = self.tmpfile.fileno()
        self.assert_equal_se(listxattr(tmp_fn), [])
        self.assert_equal_se(listxattr(tmp_fd), [])
        self.assert_equal_se(listxattr(tmp_lfn), [])
        setxattr(tmp_fn, b'user.foo', b'bar')
        setxattr(tmp_fd, b'user.bar', b'foo')
        setxattr(tmp_fn, b'user.empty', b'')
        if not is_linux:
            # linux does not allow setting user.* xattrs on symlinks
            setxattr(tmp_lfn, b'user.linkxattr', b'baz')
        self.assert_equal_se(listxattr(tmp_fn), [b'user.foo', b'user.bar', b'user.empty'])
        self.assert_equal_se(listxattr(tmp_fd), [b'user.foo', b'user.bar', b'user.empty'])
        self.assert_equal_se(listxattr(tmp_lfn, follow_symlinks=True), [b'user.foo', b'user.bar', b'user.empty'])
        if not is_linux:
            self.assert_equal_se(listxattr(tmp_lfn), [b'user.linkxattr'])
        self.assert_equal(getxattr(tmp_fn, b'user.foo'), b'bar')
        self.assert_equal(getxattr(tmp_fd, b'user.foo'), b'bar')
        self.assert_equal(getxattr(tmp_lfn, b'user.foo', follow_symlinks=True), b'bar')
        if not is_linux:
            self.assert_equal(getxattr(tmp_lfn, b'user.linkxattr'), b'baz')
        self.assert_equal(getxattr(tmp_fn, b'user.empty'), b'')

    def test_listxattr_buffer_growth(self):
        tmp_fn = os.fsencode(self.tmpfile.name)
        # make it work even with ext4, which imposes rather low limits
        buffer.resize(size=64, init=True)
        # xattr raw key list will be > 64
        keys = [b'user.attr%d' % i for i in range(20)]
        for key in keys:
            setxattr(tmp_fn, key, b'x')
        got_keys = listxattr(tmp_fn)
        self.assert_equal_se(got_keys, keys)
        self.assert_true(len(buffer) > 64)

    def test_getxattr_buffer_growth(self):
        tmp_fn = os.fsencode(self.tmpfile.name)
        # make it work even with ext4, which imposes rather low limits
        buffer.resize(size=64, init=True)
        value = b'x' * 126
        setxattr(tmp_fn, b'user.big', value)
        got_value = getxattr(tmp_fn, b'user.big')
        self.assert_equal(value, got_value)
        self.assert_equal(len(buffer), 128)


@pytest.mark.parametrize('lstring, splitted', (
    (b'', []),
    (b'\x00', [b'']),
    (b'\x01a', [b'a']),
    (b'\x01a\x02cd', [b'a', b'cd']),
))
def test_split_lstring(lstring, splitted):
    assert split_lstring(lstring) == splitted
