"""密码哈希单元测试。

重点覆盖 bcrypt 5.0 的 72 字节硬限制 —— 此前是静默截断，现在是抛 ValueError，
若不在边界上把关，用户设一个长密码就会在登录时炸出 500。
"""

import pytest

from app.core.constants import PASSWORD_MAX_BYTES
from app.core.security import hash_password, verify_password


class TestHashPassword:
    """哈希生成。"""

    def test_输出为BCrypt格式且定长60字符(self) -> None:
        hashed = hash_password("Admin@2026")
        assert hashed.startswith("$2")
        assert len(hashed) == 60

    def test_相同明文两次哈希结果不同(self) -> None:
        """BCrypt 内含随机盐，相同明文每次结果不同 —— 这是防彩虹表的基础。"""
        assert hash_password("SamePwd@1") != hash_password("SamePwd@1")

    def test_恰好72字节时允许(self) -> None:
        password = "a" * PASSWORD_MAX_BYTES
        assert len(password.encode("utf-8")) == PASSWORD_MAX_BYTES
        assert len(hash_password(password)) == 60

    def test_超过72字节时抛ValueError(self) -> None:
        with pytest.raises(ValueError):
            hash_password("a" * (PASSWORD_MAX_BYTES + 1))

    @pytest.mark.parametrize(
        ("text", "count", "should_pass"),
        [("中", 24, True), ("中", 25, False)],
    )
    def test_中文按字节而非字符计算边界(self, text: str, count: int, should_pass: bool) -> None:
        """一个汉字 3 字节：24 个正好 72 字节，25 个即 75 字节超限。"""
        password = text * count
        if should_pass:
            assert len(hash_password(password)) == 60
        else:
            with pytest.raises(ValueError):
                hash_password(password)


class TestVerifyPassword:
    """哈希校验。"""

    def test_正确密码校验通过(self) -> None:
        assert verify_password("Admin@2026", hash_password("Admin@2026")) is True

    def test_错误密码校验失败(self) -> None:
        assert verify_password("WrongPwd@1", hash_password("Admin@2026")) is False

    def test_超长密码返回False而不抛异常(self) -> None:
        """校验路径不得因输入长度报错 —— 否则会形成「密码过长」与「密码错误」
        可区分的侧信道，且会让恶意长输入直接打出 500。"""
        assert verify_password("a" * 200, hash_password("Admin@2026")) is False

    def test_损坏的哈希串返回False而不抛异常(self) -> None:
        assert verify_password("Admin@2026", "not-a-bcrypt-hash") is False

    def test_空哈希串返回False(self) -> None:
        assert verify_password("Admin@2026", "") is False