from __future__ import annotations

import hashlib
import hmac
import logging
import os

logger = logging.getLogger(__name__)


class HelpScoutWebhookHandler:
    def __init__(self, queue):
        self._queue = queue

    async def handle(self, payload: dict) -> dict:
        event_type = payload.pop("_event_type", "unknown")
        logger.debug(
            "Help Scout webhook received: type=%s conversation_id=%s",
            event_type,
            payload.get("conversation", {}).get("id", "N/A"),
        )

        if self._queue is not None:
            await self._queue.put((event_type, payload))

        return {"status": "ok"}

    @staticmethod
    def verify_signature(raw_body: bytes, signature: str) -> bool:
        secret = os.getenv("HELPSCOUT_WEBHOOK_SECRET", "")
        if not secret:
            logger.warning("HELPSCOUT_WEBHOOK_SECRET not set — skipping signature verification")
            return True

        if not signature:
            return False

        expected = hmac.new(
            secret.encode(),
            raw_body,
            hashlib.sha1,
        ).hexdigest()

        return hmac.compare_digest(expected, signature)