from test import support
from test.support.script_helper import assert_python_ok, assert_python_failure
import builtins
import codecs
import gc
import locale
import operator
import os
import struct
import subprocess
import sys
import sysconfig
import test.support
import textwrap
import unittest
import warnings


# count the number of test runs, used to create unique
# strings to intern in test_intern()
INTERN_NUMRUNS = 0


class DisplayHookTest(unittest.TestCase):

    def test_original_displayhook(self):
        dh = sys.__displayhook__

        with support.captured_stdout() as out:
            dh(42)

        self.assertEqual(out.getvalue(), "42\n")
        self.assertEqual(builtins._, 42)

        del builtins._

        with support.captured_stdout() as out:
            dh(None)

        self.assertEqual(out.getvalue(), "")
        self.assertTrue(not hasattr(builtins, "_"))

        # sys.displayhook() requires arguments
        self.assertRaises(TypeError, dh)

        stdout = sys.stdout
        try:
            del sys.stdout
            self.assertRaises(RuntimeError, dh, 42)
        finally:
            sys.stdout = stdout

    def test_lost_displayhook(self):
        displayhook = sys.displayhook
        try:
            del sys.displayhook
            code = compile("42", "<string>", "single")
            self.assertRaises(RuntimeError, eval, code)
        finally:
            sys.displayhook = displayhook

    def test_custom_displayhook(self):
        def baddisplayhook(obj):
            raise ValueError

        with support.swap_attr(sys, 'displayhook', baddisplayhook):
            code = compile("42", "<string>", "single")
            self.assertRaises(ValueError, eval, code)


class ExceptHookTest(unittest.TestCase):

    def test_original_excepthook(self):
        try:
            raise ValueError(42)
        except ValueError as exc:
            with support.captured_stderr() as err:
                sys.__excepthook__(*sys.exc_info())

        self.assertTrue(err.getvalue().endswith("ValueError: 42\n"))

        self.assertRaises(TypeError, sys.__excepthook__)

    def test_excepthook_bytes_filename(self):
        # bpo-37467: sys.excepthook() must not crash if a filename
        # is a bytes string
        with warnings.catch_warnings():
            warnings.simplefilter('ignore', BytesWarning)

            try:
                raise SyntaxError("msg", (b"bytes_filename", 123, 0, "text"))
            except SyntaxError as exc:
                with support.captured_stderr() as err:
                    sys.__excepthook__(*sys.exc_info())

        err = err.getvalue()
        self.assertIn("""  File "b'bytes_filename'", line 123\n""", err)
        self.assertIn("""    text\n""", err)
        self.assertTrue(err.endswith("SyntaxError: msg\n"))

    def test_excepthook(self):
        with test.support.captured_output("stderr") as stderr:
            sys.excepthook(1, '1', 1)
        self.assertTrue("TypeError: print_exception(): Exception expected for " \
                         "value, str found" in stderr.getvalue())

    # FIXME: testing the code for a lost or replaced excepthook in
    # Python/pythonrun.c::PyErr_PrintEx() is tricky.


class SysModuleTest(unittest.TestCase):

    def tearDown(self):
        test.support.reap_children()

    def test_exit(self):
        # call with two arguments
        self.assertRaises(TypeError, sys.exit, 42, 42)

        # call without argument
        with self.assertRaises(SystemExit) as cm:
            sys.exit()
        self.assertIsNone(cm.exception.code)

        rc, out, err = assert_python_ok('-c', 'import sys; sys.exit()')
        self.assertEqual(rc, 0)
        self.assertEqual(out, b'')
        self.assertEqual(err, b'')

        # call with integer argument
        with self.assertRaises(SystemExit) as cm:
            sys.exit(42)
        self.assertEqual(cm.exception.code, 42)

        # call with tuple argument with one entry
        # entry will be unpacked
        with self.assertRaises(SystemExit) as cm:
            sys.exit((42,))
        self.assertEqual(cm.exception.code, 42)

        # call with string argument
        with self.assertRaises(SystemExit) as cm:
            sys.exit("exit")
        self.assertEqual(cm.exception.code, "exit")

        # call with tuple argument with two entries
        with self.assertRaises(SystemExit) as cm:
            sys.exit((17, 23))
        self.assertEqual(cm.exception.code, (17, 23))

        # test that the exit machinery handles SystemExits properly
        rc, out, err = assert_python_failure('-c', 'raise SystemExit(47)')
        self.assertEqual(rc, 47)
        self.assertEqual(out, b'')
        self.assertEqual(err, b'')

        def check_exit_message(code, expected, **env_vars):
            rc, out, err = assert_python_failure('-c', code, **env_vars)
            self.assertEqual(rc, 1)
            self.assertEqual(out, b'')
            self.assertTrue(err.startswith(expected),
                "%s doesn't start with %s" % (ascii(err), ascii(expected)))

        # test that stderr buffer is flushed before the exit message is written
        # into stderr
        check_exit_message(
            r'import sys; sys.stderr.write("unflushed,"); sys.exit("message")',
            b"unflushed,message")

        # test that the exit message is written with backslashreplace error
        # handler to stderr
        check_exit_message(
            r'import sys; sys.exit("surrogates:\uDCFF")',
            b"surrogates:\\udcff")

        # test that the unicode message is encoded to the stderr encoding
        # instead of the default encoding (utf8)
        check_exit_message(
            r'import sys; sys.exit("h\xe9")',
            b"h\xe9", PYTHONIOENCODING='latin-1')

    def test_getdefaultencoding(self):
        self.assertRaises(TypeError, sys.getdefaultencoding, 42)
        # can't check more than the type, as the user might have changed it
        self.assertIsInstance(sys.getdefaultencoding(), str)

    # testing sys.settrace() is done in test_sys_settrace.py
    # testing sys.setprofile() is done in test_sys_setprofile.py

    def test_setcheckinterval(self):
        with warnings.catch_warnings():
            warnings.simplefilter("ignore")
            self.assertRaises(TypeError, sys.setcheckinterval)
            orig = sys.getcheckinterval()
            for n in 0, 100, 120, orig: # orig last to restore starting state
                sys.setcheckinterval(n)
                self.assertEqual(sys.getcheckinterval(), n)

    def test_switchinterval(self):
        self.assertRaises(TypeError, sys.setswitchinterval)
        self.assertRaises(TypeError, sys.setswitchinterval, "a")
        self.assertRaises(ValueError, sys.setswitchinterval, -1.0)
        self.assertRaises(ValueError, sys.setswitchinterval, 0.0)
        orig = sys.getswitchinterval()
        # sanity check
        self.assertTrue(orig < 0.5, orig)
        try:
            for n in 0.00001, 0.05, 3.0, orig:
                sys.setswitchinterval(n)
                self.assertAlmostEqual(sys.getswitchinterval(), n)
        finally:
            sys.setswitchinterval(orig)

    def test_recursionlimit(self):
        self.assertRaises(TypeError, sys.getrecursionlimit, 42)
        oldlimit = sys.getrecursionlimit()
        self.assertRaises(TypeError, sys.setrecursionlimit)
        self.assertRaises(ValueError, sys.setrecursionlimit, -42)
        sys.setrecursionlimit(10000)
        self.assertEqual(sys.getrecursionlimit(), 10000)
        sys.setrecursionlimit(oldlimit)

    def test_recursionlimit_recovery(self):
        if hasattr(sys, 'gettrace') and sys.gettrace():
            self.skipTest('fatal error if run with a trace function')

        oldlimit = sys.getrecursionlimit()
        def f():
            f()
        try:
            for depth in (10, 25, 50, 75, 100, 250, 1000):
                try:
                    sys.setrecursionlimit(depth)
                except RecursionError:
                    # Issue #25274: The recursion limit is too low at the
                    # current recursion depth
                    continue

                # Issue #5392: test stack overflow after hitting recursion
                # limit twice
                self.assertRaises(RecursionError, f)
                self.assertRaises(RecursionError, f)
        finally:
            sys.setrecursionlimit(oldlimit)

    @test.support.cpython_only
    def test_setrecursionlimit_recursion_depth(self):
        # Issue #25274: Setting a low recursion limit must be blocked if the
        # current recursion depth is already higher than the "lower-water
        # mark". Otherwise, it may not be possible anymore to
        # reset the overflowed flag to 0.

        from _testcapi import get_recursion_depth

        def set_recursion_limit_at_depth(depth, limit):
            recursion_depth = get_recursion_depth()
            if recursion_depth >= depth:
                with self.assertRaises(RecursionError) as cm:
                    sys.setrecursionlimit(limit)
                self.assertRegex(str(cm.exception),
                                 "cannot set the recursion limit to [0-9]+ "
                                 "at the recursion depth [0-9]+: "
                                 "the limit is too low")
            else:
                set_recursion_limit_at_depth(depth, limit)

        oldlimit = sys.getrecursionlimit()
        try:
            sys.setrecursionlimit(1000)

            for limit in (10, 25, 50, 75, 100, 150, 200):
                # formula extracted from _Py_RecursionLimitLowerWaterMark()
                if limit > 200:
                    depth = limit - 50
                else:
                    depth = limit * 3 // 4
                set_recursion_limit_at_depth(depth, limit)
        finally:
            sys.setrecursionlimit(oldlimit)

    def test_recursionlimit_fatalerror(self):
        # A fatal error occurs if a second recursion limit is hit when recovering
        # from a first one.
        code = textwrap.dedent("""
            import sys

            def f():
                try:
                    f()
                except RecursionError:
                    f()

            sys.setrecursionlimit(%d)
            f()""")
        with test.support.SuppressCrashReport():
            for i in (50, 1000):
                sub = subprocess.Popen([sys.executable, '-c', code % i],
                    stderr=subprocess.PIPE)
                err = sub.communicate()[1]
                self.assertTrue(sub.returncode, sub.returncode)
                self.assertIn(
                    b"Fatal Python error: Cannot recover from stack overflow",
                    err)

    def test_getwindowsversion(self):
        # Raise SkipTest if sys doesn't have getwindowsversion attribute
        test.support.get_attribute(sys, "getwindowsversion")
        v = sys.getwindowsversion()
        self.assertEqual(len(v), 5)
        self.assertIsInstance(v[0], int)
        self.assertIsInstance(v[1], int)
        self.assertIsInstance(v[2], int)
        self.assertIsInstance(v[3], int)
        self.assertIsInstance(v[4], str)
        self.assertRaises(IndexError, operator.getitem, v, 5)
        self.assertIsInstance(v.major, int)
        self.assertIsInstance(v.minor, int)
        self.assertIsInstance(v.build, int)
        self.assertIsInstance(v.platform, int)
        self.assertIsInstance(v.service_pack, str)
        self.assertIsInstance(v.service_pack_minor, int)
        self.assertIsInstance(v.service_pack_major, int)
        self.assertIsInstance(v.suite_mask, int)
        self.assertIsInstance(v.product_type, int)
        self.assertEqual(v[0], v.major)
        self.assertEqual(v[1], v.minor)
        self.assertEqual(v[2], v.build)
        self.assertEqual(v[3], v.platform)
        self.assertEqual(v[4], v.service_pack)

        # This is how platform.py calls it. Make sure tuple
        #  still has 5 elements
        maj, min, buildno, plat, csd = sys.getwindowsversion()

    def test_call_tracing(self):
        self.assertRaises(TypeError, sys.call_tracing, type, 2)

    @unittest.skipUnless(hasattr(sys, "setdlopenflags"),
                         'test needs sys.setdlopenflags()')
    def test_dlopenflags(self):
        self.assertTrue(hasattr(sys, "getdlopenflags"))
        self.assertRaises(TypeError, sys.getdlopenflags, 42)
        oldflags = sys.getdlopenflags()
        self.assertRaises(TypeError, sys.setdlopenflags)
        sys.setdlopenflags(oldflags+1)