import contextlib
import errno
import importlib
import io
import os
import shutil
import socket
import stat
import subprocess
import sys
import tempfile
import textwrap
import time
import unittest
from test import support
from test.support import script_helper

TESTFN = support.TESTFN


class TestSupport(unittest.TestCase):

    def test_import_module(self):
        support.import_module("ftplib")
        self.assertRaises(unittest.SkipTest, support.import_module, "foo")

    def test_import_fresh_module(self):
        support.import_fresh_module("ftplib")

    def test_get_attribute(self):
        self.assertEqual(support.get_attribute(self, "test_get_attribute"),
                        self.test_get_attribute)
        self.assertRaises(unittest.SkipTest, support.get_attribute, self, "foo")

    @unittest.skip("failing buildbots")
    def test_get_original_stdout(self):
        self.assertEqual(support.get_original_stdout(), sys.stdout)

    def test_unload(self):
        import sched
        self.assertIn("sched", sys.modules)
        support.unload("sched")
        self.assertNotIn("sched", sys.modules)

    def test_unlink(self):
        with open(TESTFN, "w") as f:
            pass
        support.unlink(TESTFN)
        self.assertFalse(os.path.exists(TESTFN))
        support.unlink(TESTFN)

    def test_rmtree(self):
        dirpath = support.TESTFN + 'd'
        subdirpath = os.path.join(dirpath, 'subdir')
        os.mkdir(dirpath)
        os.mkdir(subdirpath)
        support.rmtree(dirpath)
        self.assertFalse(os.path.exists(dirpath))
        with support.swap_attr(support, 'verbose', 0):
            support.rmtree(dirpath)

        os.mkdir(dirpath)
        os.mkdir(subdirpath)
        os.chmod(dirpath, stat.S_IRUSR|stat.S_IXUSR)
        with support.swap_attr(support, 'verbose', 0):
            support.rmtree(dirpath)
        self.assertFalse(os.path.exists(dirpath))

        os.mkdir(dirpath)
        os.mkdir(subdirpath)
        os.chmod(dirpath, 0)
        with support.swap_attr(support, 'verbose', 0):
            support.rmtree(dirpath)
        self.assertFalse(os.path.exists(dirpath))

    def test_forget(self):
        mod_filename = TESTFN + '.py'
        with open(mod_filename, 'w') as f:
            print('foo = 1', file=f)
        sys.path.insert(0, os.curdir)
        importlib.invalidate_caches()
        try:
            mod = __import__(TESTFN)
            self.assertIn(TESTFN, sys.modules)

            support.forget(TESTFN)
            self.assertNotIn(TESTFN, sys.modules)
        finally:
            del sys.path[0]
            support.unlink(mod_filename)
            support.rmtree('__pycache__')

    def test_HOST(self):
        s = socket.create_server((support.HOST, 0))
        s.close()

    def test_find_unused_port(self):
        port = support.find_unused_port()
        s = socket.create_server((support.HOST, port))
        s.close()

    def test_bind_port(self):
        s = socket.socket()
        support.bind_port(s)
        s.listen()
        s.close()

    # Tests for temp_dir()

    def test_temp_dir(self):
        """Test that temp_dir() creates and destroys its directory."""
        parent_dir = tempfile.mkdtemp()
        parent_dir = os.path.realpath(parent_dir)

        try:
            path = os.path.join(parent_dir, 'temp')
            self.assertFalse(os.path.isdir(path))
            with support.temp_dir(path) as temp_path:
                self.assertEqual(temp_path, path)
                self.assertTrue(os.path.isdir(path))
            self.assertFalse(os.path.isdir(path))
        finally:
            support.rmtree(parent_dir)

    def test_temp_dir__path_none(self):
        """Test passing no path."""
        with support.temp_dir() as temp_path:
            self.assertTrue(os.path.isdir(temp_path))
        self.assertFalse(os.path.isdir(temp_path))

    def test_temp_dir__existing_dir__quiet_default(self):
        """Test passing a directory that already exists."""
        def call_temp_dir(path):
            with support.temp_dir(path) as temp_path:
                raise Exception("should not get here")

        path = tempfile.mkdtemp()
        path = os.path.realpath(path)
        try:
            self.assertTrue(os.path.isdir(path))
            self.assertRaises(FileExistsError, call_temp_dir, path)
            # Make sure temp_dir did not delete the original directory.
            self.assertTrue(os.path.isdir(path))
        finally:
            shutil.rmtree(path)

    def test_temp_dir__existing_dir__quiet_true(self):
        """Test passing a directory that already exists with quiet=True."""
        path = tempfile.mkdtemp()
        path = os.path.realpath(path)

        try:
            with support.check_warnings() as recorder:
                with support.temp_dir(path, quiet=True) as temp_path:
                    self.assertEqual(path, temp_path)
                warnings = [str(w.message) for w in recorder.warnings]
            # Make sure temp_dir did not delete the original directory.
            self.assertTrue(os.path.isdir(path))
        finally:
            shutil.rmtree(path)

        self.assertEqual(len(warnings), 1, warnings)
        warn = warnings[0]
        self.assertTrue(warn.startswith(f'tests may fail, unable to create '
                                        f'temporary directory {path!r}: '),
                        warn)

    @unittest.skipUnless(hasattr(os, "fork"), "test requires os.fork")
    def test_temp_dir__forked_child(self):
        """Test that a forked child process does not remove the directory."""
        # See bpo-30028 for details.
        # Run the test as an external script, because it uses fork.
        script_helper.assert_python_ok("-c", textwrap.dedent("""
            import os
            from test import support
            with support.temp_cwd() as temp_path:
                pid = os.fork()
                if pid != 0:
                    # parent process (child has pid == 0)

                    # wait for the child to terminate
                    (pid, status) = os.waitpid(pid, 0)
                    if status != 0:
                        raise AssertionError(f"Child process failed with exit "
                                             f"status indication 0x{status:x}.")

                    # Make sure that temp_path is still present. When the child
                    # process leaves the 'temp_cwd'-context, the __exit__()-
                    # method of the context must not remove the temporary
                    # directory.
                    if not os.path.isdir(temp_path):
                        raise AssertionError("Child removed temp_path.")
        """))

    # Tests for change_cwd()

    def test_change_cwd(self):
        original_cwd = os.getcwd()

        with support.temp_dir() as temp_path:
            with support.change_cwd(temp_path) as new_cwd:
                self.assertEqual(new_cwd, temp_path)
                self.assertEqual(os.getcwd(), new_cwd)

        self.assertEqual(os.getcwd(), original_cwd)

    def test_change_cwd__non_existent_dir(self):
        """Test passing a non-existent directory."""
        original_cwd = os.getcwd()

        def call_change_cwd(path):
            with support.change_cwd(path) as new_cwd:
                raise Exception("should not get here")

        with support.temp_dir() as parent_dir:
            non_existent_dir = os.path.join(parent_dir, 'does_not_exist')
            self.assertRaises(FileNotFoundError, call_change_cwd,
                              non_existent_dir)

        self.assertEqual(os.getcwd(), original_cwd)

    def test_change_cwd__non_existent_dir__quiet_true(self):
        """Test passing a non-existent directory with quiet=True."""
        original_cwd = os.getcwd()

        with support.temp_dir() as parent_dir:
            bad_dir = os.path.join(parent_dir, 'does_not_exist')
            with support.check_warnings() as recorder:
                with support.change_cwd(bad_dir, quiet=True) as new_cwd:
                    self.assertEqual(new_cwd, original_cwd)
                    self.assertEqual(os.getcwd(), new_cwd)
                warnings = [str(w.message) for w in recorder.warnings]

        self.assertEqual(len(warnings), 1, warnings)
        warn = warnings[0]
        self.assertTrue(warn.startswith(f'tests may fail, unable to change '
                                        f'the current working directory '
                                        f'to {bad_dir!r}: '),
                        warn)

    # Tests for change_cwd()

    def test_change_cwd__chdir_warning(self):
        """Check the warning message when os.chdir() fails."""
        path = TESTFN + '_does_not_exist'
        with support.check_warnings() as recorder:
            with support.change_cwd(path=path, quiet=True):
                pass
            messages = [str(w.message) for w in recorder.warnings]

        self.assertEqual(len(messages), 1, messages)
        msg = messages[0]
        self.assertTrue(msg.startswith(f'tests may fail, unable to change '
                                       f'the current working directory '
                                       f'to {path!r}: '),
                        msg)

    # Tests for temp_cwd()

    def test_temp_cwd(self):
        here = os.getcwd()
        with support.temp_cwd(name=TESTFN):
            self.assertEqual(os.path.basename(os.getcwd()), TESTFN)
        self.assertFalse(os.path.exists(TESTFN))
        self.assertEqual(os.getcwd(), here)


    def test_temp_cwd__name_none(self):
        """Test passing None to temp_cwd()."""
        original_cwd = os.getcwd()
        with support.temp_cwd(name=None) as new_cwd:
            self.assertNotEqual(new_cwd, original_cwd)
            self.assertTrue(os.path.isdir(new_cwd))
            self.assertEqual(os.getcwd(), new_cwd)
        self.assertEqual(os.getcwd(), original_cwd)

    def test_sortdict(self):
        self.assertEqual(support.sortdict({3:3, 2:2, 1:1}), "{1: 1, 2: 2, 3: 3}")

    def test_make_bad_fd(self):
        fd = support.make_bad_fd()
        with self.assertRaises(OSError) as cm:
            os.write(fd, b"foo")
        self.assertEqual(cm.exception.errno, errno.EBADF)

    def test_check_syntax_error(self):
        support.check_syntax_error(self, "def class", lineno=1, offset=5)
        with self.assertRaises(AssertionError):
            support.check_syntax_error(self, "x=1")

    def test_CleanImport(self):
        import importlib
        with support.CleanImport("asyncore"):
            importlib.import_module("asyncore")

    def test_DirsOnSysPath(self):
        with support.DirsOnSysPath('foo', 'bar'):
            self.assertIn("foo", sys.path)
            self.assertIn("bar", sys.path)
        self.assertNotIn("foo", sys.path)
        self.assertNotIn("bar", sys.path)

    def test_captured_stdout(self):
        with support.captured_stdout() as stdout:
            print("hello")
        self.assertEqual(stdout.getvalue(), "hello\n")

    def test_captured_stderr(self):
        with support.captured_stderr() as stderr:
            print("hello", file=sys.stderr)
        self.assertEqual(stderr.getvalue(), "hello\n")

    def test_captured_stdin(self):
        with support.captured_stdin() as stdin:
            stdin.write('hello\n')
            stdin.seek(0)
            # call test code that consumes from sys.stdin
            captured = input()
        self.assertEqual(captured, "hello")

    def test_gc_collect(self):
        support.gc_collect()

    def test_python_is_optimized(self):
        self.assertIsInstance(support.python_is_optimized(), bool)

    def test_swap_attr(self):
        class Obj:
            pass
        obj = Obj()
        obj.x = 1
        with support.swap_attr(obj, "x", 5) as x:
            self.assertEqual(obj.x, 5)
            self.assertEqual(x, 1)
        self.assertEqual(obj.x, 1)
        with support.swap_attr(obj, "y", 5) as y:
            self.assertEqual(obj.y, 5)
            self.assertIsNone(y)
        self.assertFalse(hasattr(obj, 'y'))
        with support.swap_attr(obj, "y", 5):
            del obj.y
        self.assertFalse(hasattr(obj, 'y'))

    def test_swap_item(self):
        D = {"x":1}
        with support.swap_item(D, "x", 5) as x:
            self.assertEqual(D["x"], 5)
            self.assertEqual(x, 1)
        self.assertEqual(D["x"], 1)
        with support.swap_item(D, "y", 5) as y:
            self.assertEqual(D["y"], 5)
            self.assertIsNone(y)
        self.assertNotIn("y", D)
        with support.swap_item(D, "y", 5):
            del D["y"]
        self.assertNotIn("y", D)

    class RefClass:
        attribute1 = None
        attribute2 = None
        _hidden_attribute1 = None
        __magic_1__ = None

    class OtherClass:
        attribute2 = None
        attribute3 = None
        __magic_1__ = None
        __magic_2__ = None

    def test_detect_api_mismatch(self):
        missing_items = support.detect_api_mismatch(self.RefClass,
                                                    self.OtherClass)
        self.assertEqual({'attribute1'}, missing_items)

        missing_items = support.detect_api_mismatch(self.OtherClass,
                                                    self.RefClass)
        self.assertEqual({'attribute3', '__magic_2__'}, missing_items)

    def test_detect_api_mismatch__ignore(self):
        ignore = ['attribute1', 'attribute3', '__magic_2__', 'not_in_either']

        missing_items = support.detect_api_mismatch(
                self.RefClass, self.OtherClass, ignore=ignore)
        self.assertEqual(set(), missing_items)

        missing_items = support.detect_api_mismatch(
                self.OtherClass, self.RefClass, ignore=ignore)
        self.assertEqual(set(), missing_items)

    def test_check__all__(self):
        extra = {'tempdir'}
        blacklist = {'template'}
        support.check__all__(self,
                             tempfile,
                             extra=extra,
                             blacklist=blacklist)

        extra = {'TextTestResult', 'installHandler'}
        blacklist = {'load_tests', "TestProgram", "BaseTestSuite"}

        support.check__all__(self,
                             unittest,
                             ("unittest.result", "unittest.case",
                              "unittest.suite", "unittest.loader",
                              "unittest.main", "unittest.runner",
                              "unittest.signals"),
                             extra=extra,
                             blacklist=blacklist)

        self.assertRaises(AssertionError, support.check__all__, self, unittest)

    @unittest.skipUnless(hasattr(os, 'waitpid') and hasattr(os, 'WNOHANG'),
                         'need os.waitpid() and os.WNOHANG')
    def test_reap_children(self):
        # Make sure that there is no other pending child process
        support.reap_children()

        # Create a child process
        pid = os.fork()
        if pid == 0:
            # child process: do nothing, just exit
            os._exit(0)

        t0 = time.monotonic()
        deadline = time.monotonic() + 60.0

        was_altered = support.environment_altered
        try:
            support.environment_altered = False
            stderr = io.StringIO()

            while True:
                if time.monotonic() > deadline:
                    self.fail("timeout")

                with contextlib.redirect_stderr(stderr):
                    support.reap_children()

                # Use environment_altered to check if reap_children() found
                # the child process
                if support.environment_altered:
                    break

                # loop until the child process completed
                time.sleep(0.100)

            msg = "Warning -- reap_children() reaped child process %s" % pid
            self.assertIn(msg, stderr.getvalue())
            self.assertTrue(support.environment_altered)
        finally:
            support.environment_altered = was_altered

        # Just in case, check again that there is no other
        # pending child process
        support.reap_children()

    def check_options(self, args, func, expected=None):
        code = f'from test.support import {func}; print(repr({func}()))'
        cmd = [sys.executable, *args, '-c', code]
        env = {key: value for key, value in os.environ.items()
               if not key.startswith('PYTHON')}
        proc = subprocess.run(cmd,
                              stdout=subprocess.PIPE,
                              stderr=subprocess.DEVNULL,
                              universal_newlines=True,
                              env=env)
        if expected is None:
            expected = args
        self.assertEqual(proc.stdout.rstrip(), repr(expected))
        self.assertEqual(proc.returncode, 0)

    def test_args_from_interpreter_flags(self):
        # Test test.support.args_from_interpreter_flags()
        for opts in (
            # no option
            [],
            # single option
            ['-B'],
            ['-s'],
            ['-S'],
            ['-E'],
            ['-v'],
            ['-b'],
            ['-q'],
            ['-I'],
            # same option multiple times
            ['-bb'],
            ['-vvv'],
            # -W options
            ['-Wignore'],
            # -X options
            ['-X', 'dev'],
            ['-Wignore', '-X', 'dev'],
            ['-X', 'faulthandler'],
            ['-X', 'importtime'],
            ['-X', 'showalloccount'],
            ['-X', 'showrefcount'],
            ['-X', 'tracemalloc'],
            ['-X', 'tracemalloc=3'],
        ):
            with self.subTest(opts=opts):
                self.check_options(opts, 'args_from_interpreter_flags')

        self.check_options(['-I', '-E', '-s'], 'args_from_interpreter_flags',
                           ['-I'])

    def test_optim_args_from_interpreter_flags(self):
        # Test test.support.optim_args_from_interpreter_flags()
        for opts in (
            # no option
            [],
            ['-O'],
            ['-OO'],
            ['-OOOO'],
        ):
            with self.subTest(opts=opts):
                self.check_options(opts, 'optim_args_from_interpreter_flags')

    def test_match_test(self):
        class Test:
            def __init__(self, test_id):
                self.test_id = test_id

            def id(self):
                return self.test_id

        test_access = Test('test.test_os.FileTests.test_access')
        test_chdir = Test('test.test_os.Win32ErrorTests.test_chdir')

        with support.swap_attr(support, '_match_test_func', None):
            # match all
            support.set_match_tests([])
            self.assertTrue(support.match_test(test_access))
            self.assertTrue(support.match_test(test_chdir))

            # match all using None
            support.set_match_tests(None)
            self.assertTrue(support.match_test(test_access))
            self.assertTrue(support.match_test(test_chdir))

            # match the full test identifier
            support.set_match_tests([test_access.id()])
            self.assertTrue(support.match_test(test_access))
            self.assertFalse(support.match_test(test_chdir))

            # match the module name
            support.set_match_tests(['test_os'])
            self.assertTrue(support.match_test(test_access))
            self.assertTrue(support.match_test(test_chdir))

            # Test '*' pattern
            support.set_match_tests(['test_*'])
            self.assertTrue(support.match_test(test_access))
            self.assertTrue(support.match_test(test_chdir))

            # Test case sensitivity
            support.set_match_tests(['filetests'])
            self.assertFalse(support.match_test(test_access))
            support.set_match_tests(['FileTests'])
            self.assertTrue(support.match_test(test_access))

            # Test pattern containing '.' and a '*' metacharacter
            support.set_match_tests(['*test_os.*.test_*'])
            self.assertTrue(support.match_test(test_access))
            self.assertTrue(support.match_test(test_chdir))

            # Multiple patterns
            support.set_match_tests([test_access.id(), test_chdir.id()])
            self.assertTrue(support.match_test(test_access))
            self.assertTrue(support.match_test(test_chdir))

            support.set_match_tests(['test_access', 'DONTMATCH'])
            self.assertTrue(support.match_test(test_access))
            self.assertFalse(support.match_test(test_chdir))

    def test_fd_count(self):
        # We cannot test the absolute value of fd_count(): on old Linux
        # kernel or glibc versions, os.urandom() keeps a FD open on
        # /dev/urandom device and Python has 4 FD opens instead of 3.
        start = support.fd_count()
        fd = os.open(__file__, os.O_RDONLY)
        try:
            more = support.fd_count()
        finally:
            os.close(fd)
        self.assertEqual(more - start, 1)

    # XXX -follows a list of untested API
    # make_legacy_pyc
    # is_resource_enabled
    # requires
    # fcmp
    # umaks
    # findfile
    # check_warnings
    # EnvironmentVarGuard
    # TransientResource
    # transient_internet
    # run_with_locale
    # set_memlimit
    # bigmemtest
    # precisionbigmemtest
    # bigaddrspacetest
    # requires_resource
    # run_doctest
    # threading_cleanup
    # reap_threads
    # strip_python_stderr
    # can_symlink
    # skip_unless_symlink
    # SuppressCrashReport


def test_main():
    tests = [TestSupport]
    support.run_unittest(*tests)

if __name__ == '__main__':
    test_main()