#
# Tests for the `osbuild.util.linux` module.
#

import os
import subprocess
import tempfile
import unittest

from osbuild.util import linux


def can_set_immutable():
    with tempfile.TemporaryDirectory(dir="/var/tmp") as tmp:
        try:
            os.makedirs(f"{tmp}/f")
            # fist they give it ...
            subprocess.run(["chattr", "+i", f"{tmp}/f"], check=True)
            # ... then they take it away
            subprocess.run(["chattr", "-i", f"{tmp}/f"], check=True)
        except (subprocess.CalledProcessError, FileNotFoundError):
            return False
        return True


class TestUtilLinux(unittest.TestCase):
    def setUp(self):
        self.vartmpdir = tempfile.TemporaryDirectory(dir="/var/tmp")

    def tearDown(self):
        self.vartmpdir.cleanup()

    def test_ioctl_get_immutable(self):
        #
        # Test the `ioctl_get_immutable()` helper and make sure it works
        # as intended.
        #

        with open(f"{self.vartmpdir.name}/immutable", "x") as f:
            assert not linux.ioctl_get_immutable(f.fileno())

    @unittest.skipUnless(can_set_immutable(), "root-only")
    def test_ioctl_toggle_immutable(self):
        #
        # Test the `ioctl_toggle_immutable()` helper and make sure it works
        # as intended.
        #

        with open(f"{self.vartmpdir.name}/immutable", "x") as f:
            # Check the file is mutable by default and if we clear it again.
            assert not linux.ioctl_get_immutable(f.fileno())
            linux.ioctl_toggle_immutable(f.fileno(), False)
            assert not linux.ioctl_get_immutable(f.fileno())

            # Set immutable and check for it. Try again to verify with flag set.
            linux.ioctl_toggle_immutable(f.fileno(), True)
            assert linux.ioctl_get_immutable(f.fileno())
            linux.ioctl_toggle_immutable(f.fileno(), True)
            assert linux.ioctl_get_immutable(f.fileno())

            # Verify immutable files cannot be unlinked.
            with self.assertRaises(OSError):
                os.unlink(f"{self.vartmpdir.name}/immutable")

            # Check again that clearing the flag works.
            linux.ioctl_toggle_immutable(f.fileno(), False)
            assert not linux.ioctl_get_immutable(f.fileno())

            # This time, check that we actually set the same flag as `chattr`.
            subprocess.run(["chattr", "+i",
                            f"{self.vartmpdir.name}/immutable"], check=True)
            assert linux.ioctl_get_immutable(f.fileno())

            # Same for clearing it.
            subprocess.run(["chattr", "-i",
                            f"{self.vartmpdir.name}/immutable"], check=True)
            assert not linux.ioctl_get_immutable(f.fileno())

            # Verify we can unlink the file again, once the flag is cleared.
            os.unlink(f"{self.vartmpdir.name}/immutable")