import json
import logging

from fastapi import APIRouter, Depends, HTTPException
from pywebpush import WebPushException, webpush
from sqlmodel import Session, select

from app.auth import get_current_user
from app.config import settings
from app.db import get_session
from app.models.models import PushSubscription, PushSubscriptionCreate

logger = logging.getLogger(__name__)

router = APIRouter(prefix="/notifications", tags=["notifications"])


@router.get("/vapid-public-key")
def get_vapid_public_key(_user: str = Depends(get_current_user)):
    if not settings.VAPID_PUBLIC_KEY:
        raise HTTPException(status_code=503, detail="Push notifications not configured")
    return {"publicKey": settings.VAPID_PUBLIC_KEY}


@router.post("/subscribe", status_code=201)
def subscribe(
    data: PushSubscriptionCreate,
    session: Session = Depends(get_session),
    _user: str = Depends(get_current_user),
):
    existing = session.exec(
        select(PushSubscription).where(PushSubscription.endpoint == data.endpoint)
    ).first()
    if existing:
        existing.p256dh = data.keys["p256dh"]
        existing.auth = data.keys["auth"]
        session.add(existing)
        session.commit()
        return {"status": "updated"}

    sub = PushSubscription(
        endpoint=data.endpoint,
        p256dh=data.keys["p256dh"],
        auth=data.keys["auth"],
    )
    session.add(sub)
    session.commit()
    return {"status": "subscribed"}


@router.delete("/unsubscribe")
def unsubscribe(
    data: PushSubscriptionCreate,
    session: Session = Depends(get_session),
    _user: str = Depends(get_current_user),
):
    existing = session.exec(
        select(PushSubscription).where(PushSubscription.endpoint == data.endpoint)
    ).first()
    if existing:
        session.delete(existing)
        session.commit()
    return {"status": "unsubscribed"}


def send_push_to_all(session: Session, title: str, body: str, url: str = "/"):
    """Send a push notification to all registered subscriptions."""
    if not settings.VAPID_PRIVATE_KEY or not settings.VAPID_PUBLIC_KEY:
        logger.debug("VAPID keys not configured, skipping push notification")
        return

    subscriptions = session.exec(select(PushSubscription)).all()
    payload = json.dumps({"title": title, "body": body, "url": url})

    for sub in subscriptions:
        subscription_info = {
            "endpoint": sub.endpoint,
            "keys": {"p256dh": sub.p256dh, "auth": sub.auth},
        }
        try:
            webpush(
                subscription_info=subscription_info,
                data=payload,
                vapid_private_key=settings.VAPID_PRIVATE_KEY,
                vapid_claims={"sub": settings.VAPID_CLAIM_EMAIL},
            )
        except WebPushException as e:
            logger.warning("Push failed for %s: %s", sub.endpoint[:50], e)
            if e.response and e.response.status_code in (404, 410):
                session.delete(sub)
                session.commit()
        except Exception:
            logger.exception("Unexpected push error for %s", sub.endpoint[:50])