"""Internationalization primitives (spec §7.1 Punycode / §7.2 SMTPUTF8)."""
import unittest

from app.validator.i18n import (
    EAI_REASON,
    domain_is_unicode,
    eai_gate,
    local_part_is_ascii,
    to_punycode,
)


class PunycodeTests(unittest.TestCase):
    def test_ascii_domain_untouched(self):
        self.assertEqual(to_punycode("example.com"), "example.com")

    def test_unicode_domain_encoded(self):
        out = to_punycode("bücher.example")
        self.assertTrue(out.startswith("xn--"))
        self.assertEqual(out.encode("ascii").decode(), out)

    def test_already_punycode_roundtrip(self):
        self.assertEqual(to_punycode("xn--bcher-kva.example"), "xn--bcher-kva.example")

    def test_unicode_tld(self):
        out = to_punycode("пример.рф")
        self.assertTrue(all(ord(c) < 128 for c in out))
        self.assertIn("xn--", out)

    def test_garbage_domain_returns_as_is(self):
        # Must never raise — DNS will fail naturally and the verdict degrades.
        self.assertEqual(to_punycode("\x00bad"), "\x00bad")

    def test_empty_and_dot_stripping_safe(self):
        self.assertEqual(to_punycode(""), "")
        self.assertEqual(to_punycode("example.com"), "example.com")


class UnicodeDetectionTests(unittest.TestCase):
    def test_domain_is_unicode(self):
        self.assertTrue(domain_is_unicode("münchen.de"))
        self.assertFalse(domain_is_unicode("xn--mnchen-3ya.de"))
        self.assertFalse(domain_is_unicode("example.com"))


class EAITests(unittest.TestCase):
    def test_ascii_local_passes_gate(self):
        self.assertIsNone(eai_gate("john.smith"))
        self.assertIsNone(eai_gate("o+brien+tag"))

    def test_unicode_local_blocked_deterministically(self):
        self.assertEqual(eai_gate("用户"), EAI_REASON)
        self.assertEqual(eai_gate("café"), EAI_REASON)

    def test_ascii_flag_consistency(self):
        self.assertTrue(local_part_is_ascii("simple"))
        self.assertFalse(local_part_is_ascii("日本語"))


if __name__ == "__main__":
    unittest.main()