from __future__ import annotations

import asyncio
import json
import logging

from backend import config

logger = logging.getLogger(__name__)


async def send_push(subscription_json: str, title: str, body: str) -> None:
    """Send a Web Push notification. Swallows all errors — never raises."""
    if not config.VAPID_PRIVATE_KEY:
        logger.warning("VAPID_PRIVATE_KEY not configured — push notification skipped")
        return
    try:
        import pywebpush  # type: ignore[import]
    except ImportError:
        logger.warning("pywebpush not installed — push notification skipped")
        return
    try:
        subscription_info = json.loads(subscription_json)
        data = json.dumps({"title": title, "body": body})
        vapid_claims = {"sub": f"mailto:{config.VAPID_CLAIMS_EMAIL or 'admin@example.com'}"}

        await asyncio.to_thread(
            pywebpush.webpush,
            subscription_info=subscription_info,
            data=data,
            vapid_private_key=config.VAPID_PRIVATE_KEY,
            vapid_claims=vapid_claims,
        )
    except Exception as exc:
        logger.error("Web Push failed: %s", exc)