import secrets
import time
import logging

logger = logging.getLogger(__name__)

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


class IntercomPairing:
    id_label = "intercomContactId"

    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("Intercom pairing code generated for contact %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)
            logger.info("Intercom pairing code expired for contact %s", peer_id)
            return False
        if not secrets.compare_digest(stored_code, code):
            return False
        _PAIRING_CODES.pop(peer_id, None)
        logger.info("Intercom pairing code verified for contact %s", peer_id)
        return True

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

    async def notify_approval(self, config: dict, peer_id: str, account_id: str | None = None) -> None:
        logger.info("Intercom pairing approved for contact %s (account=%s)", peer_id, account_id or "default")