"""Configuration and error carrier for per-user HTTP rate limiting."""

from dataclasses import dataclass

from app.core.config import Settings
from app.core.errors import RateLimitedError


class RateLimitExceededError(RateLimitedError):
    def __init__(self, message: str, retry_after_seconds: int) -> None:
        super().__init__(message)
        self.retry_after_seconds = max(1, int(retry_after_seconds))


@dataclass(frozen=True)
class RateLimitPolicy:
    enabled: bool
    window_seconds: int
    max_requests: int
    key_prefix: str

    @classmethod
    def from_settings(cls, settings: Settings) -> "RateLimitPolicy":
        return cls(settings.rate_limit_enabled, settings.rate_limit_window_seconds,
                   settings.rate_limit_max_requests, settings.rate_limit_key_prefix)

    def key(self, user_id: str, method: str, route_path: str) -> str:
        return f"{self.key_prefix}:{user_id}:{method.upper()}:{route_path}"