from __future__ import annotations

import hmac
import logging
import secrets
import time

logger = logging.getLogger(__name__)

_PAIRING_CODES: dict[str, tuple[str, float]] = {}
_CODE_TTL_SECONDS = 300


class TelegramPairing:
    id_label = "telegramUserId"

    async def generate_code(self, peer_id: str) -> str:
        code = f"{secrets.randbelow(1_000_000):06d}"
        _PAIRING_CODES[peer_id] = (code, time.monotonic())
        logger.info("Telegram pairing code generated for peer %s", peer_id)
        return code

    async def verify_code(self, peer_id: str, code: str) -> bool:
        stored = _PAIRING_CODES.get(peer_id)
        if stored is None:
            return False
        stored_code, created_at = stored
        if time.monotonic() - created_at > _CODE_TTL_SECONDS:
            _PAIRING_CODES.pop(peer_id, None)
            return False
        if not hmac.compare_digest(stored_code, code):
            return False
        _PAIRING_CODES.pop(peer_id, None)
        return True

    def normalize_allow_entry(self, entry: str) -> str:
        stripped = entry.strip()
        for prefix in ("tg:", "telegram:"):
            if stripped.startswith(prefix):
                return stripped[len(prefix):]
        return stripped

    async def notify_approval(self, config: dict, peer_id: str, account_id: str | None = None) -> None:
        logger.info("Telegram pairing approved for peer %s", peer_id)
        try:
            from yuxi.channel.extensions.telegram.config import TelegramConfigAdapter

            adapter = TelegramConfigAdapter()
            adapter._config = config
            account = await adapter.resolve_account(account_id or "default")
            token = account.get("token", "")
            if not token:
                return

            import httpx

            async with httpx.AsyncClient(timeout=httpx.Timeout(5.0)) as client:
                await client.post(
                    f"https://api.telegram.org/bot{token}/sendMessage",
                    json={
                        "chat_id": peer_id,
                        "text": "✅ 您的访问请求已批准。现在可以直接向我发送消息了。",
                        "parse_mode": "HTML",
                    },
                )
        except Exception:
            logger.warning("Failed to send approval notification to peer %s", peer_id, exc_info=True)