"""
登录频率限制器（内存实现，单用户场景适用）
"""
import time


class LoginRateLimiter:
    """IP 级别的登录频率限制"""

    MAX_ATTEMPTS = 5
    WINDOW_SECONDS = 900       # 统计窗口：15 分钟
    LOCKOUT_SECONDS = 900      # 锁定时间：15 分钟

    def __init__(self):
        self._attempts: dict[str, list[float]] = {}
        self._lockout: dict[str, float] = {}

    def _cleanup(self):
        """清除过期的记录"""
        now = time.time()
        self._attempts = {
            ip: [t for t in times if now - t < self.WINDOW_SECONDS]
            for ip, times in self._attempts.items()
        }
        self._attempts = {ip: times for ip, times in self._attempts.items() if times}

        self._lockout = {
            ip: until for ip, until in self._lockout.items()
            if now < until
        }

    def check(self, ip: str) -> tuple[bool, int | None]:
        """返回 (是否允许, 剩余等待秒数)"""
        self._cleanup()

        now = time.time()

        if ip in self._lockout:
            remaining = int(self._lockout[ip] - now)
            if remaining > 0:
                return False, remaining
            del self._lockout[ip]

        return True, None

    def record_failure(self, ip: str):
        """记录一次失败"""
        now = time.time()
        self._attempts.setdefault(ip, []).append(now)
        if len(self._attempts[ip]) >= self.MAX_ATTEMPTS:
            self._lockout[ip] = now + self.LOCKOUT_SECONDS

    def reset(self, ip: str):
        """登录成功后重置计数"""
        self._attempts.pop(ip, None)
        self._lockout.pop(ip, None)


login_limiter = LoginRateLimiter()