import { useEffect } from 'react';
import { apiFetch } from '../api-client';

const VAPID_PUBLIC_KEY = import.meta.env['VITE_VAPID_PUBLIC_KEY'] as string | undefined;

function urlBase64ToUint8Array(base64: string): Uint8Array {
  const padding = '='.repeat((4 - (base64.length % 4)) % 4);
  const b64 = (base64 + padding).replace(/-/g, '+').replace(/_/g, '/');
  const raw = atob(b64);
  return Uint8Array.from(raw, (c) => c.charCodeAt(0));
}

export function usePushRegistration() {
  useEffect(() => {
    if (!VAPID_PUBLIC_KEY || !('serviceWorker' in navigator) || !('PushManager' in window)) return;

    const register = async () => {
      try {
        const reg = await navigator.serviceWorker.ready;
        const existing = await reg.pushManager.getSubscription();
        const sub =
          existing ??
          (await reg.pushManager.subscribe({
            userVisibleOnly: true,
            applicationServerKey: urlBase64ToUint8Array(VAPID_PUBLIC_KEY),
          }));
        const json = sub.toJSON();
        await apiFetch('/notifications/subscribe', {
          method: 'POST',
          body: {
            endpoint: sub.endpoint,
            keys: { p256dh: json.keys?.['p256dh'] ?? '', auth: json.keys?.['auth'] ?? '' },
          },
        });
      } catch {
        // Push é opt-in — permissão negada ou SW não disponível é normal
      }
    };

    void register();
  }, []);
}