from __future__ import annotations

import json
from typing import Any

from flask import current_app


def push_is_configured() -> bool:
    return bool(
        current_app.config.get("VAPID_PUBLIC_KEY")
        and current_app.config.get("VAPID_PRIVATE_KEY")
        and current_app.config.get("VAPID_SUBJECT")
    )


def push_public_key() -> str | None:
    return current_app.config.get("VAPID_PUBLIC_KEY") or None


def send_push_message(subscription: dict[str, Any], *, title: str, body: str, url: str) -> tuple[bool, str | None]:
    if not push_is_configured():
        return False, "Push ist noch nicht konfiguriert."

    try:
        from pywebpush import WebPushException, webpush
    except Exception:
        return False, "Die Push-Bibliothek ist noch nicht installiert."

    payload = json.dumps(
        {
            "title": title,
            "body": body,
            "url": url,
            "icon": "/static/brand/pwa-192.png",
            "badge": "/static/brand/pwa-badge.png",
        }
    )

    try:
        webpush(
            subscription_info=subscription,
            data=payload,
            vapid_private_key=current_app.config["VAPID_PRIVATE_KEY"],
            vapid_claims={"sub": current_app.config["VAPID_SUBJECT"]},
        )
    except WebPushException as exc:  # pragma: no cover - depends on live push endpoint
        return False, str(exc)

    return True, None