from __future__ import annotations

import secrets
import time
from typing import Optional

from fastapi import Depends, Header, HTTPException, Request
from fastapi.security import HTTPAuthorizationCredentials, HTTPBearer

from backend import config

_bearer = HTTPBearer(auto_error=False)

_RATE_LIMIT = 5
_RATE_WINDOW = 600  # 10 minutes


async def verify_webhook_secret(
    x_telegram_bot_api_secret_token: str = Header(default=""),
) -> None:
    if not secrets.compare_digest(
        x_telegram_bot_api_secret_token, config.WEBHOOK_SECRET
    ):
        raise HTTPException(status_code=403, detail="Forbidden")


async def verify_admin_token(
    credentials: Optional[HTTPAuthorizationCredentials] = Depends(_bearer),
) -> None:
    if credentials is None or not secrets.compare_digest(
        credentials.credentials, config.ADMIN_TOKEN
    ):
        raise HTTPException(status_code=401, detail="Unauthorized")


async def rate_limit_register(request: Request) -> None:
    counters = request.app.state.rate_counters
    client_ip = request.client.host if request.client else "unknown"
    now = time.time()
    count, window_start = counters.get(client_ip, (0, now))
    if now - window_start >= _RATE_WINDOW:
        count = 0
        window_start = now
    count += 1
    counters[client_ip] = (count, window_start)
    if count > _RATE_LIMIT:
        raise HTTPException(status_code=429, detail="Too Many Requests")