import axios from 'axios';

export const initSw = async () => {
    if (!('serviceWorker' in navigator) || !('PushManager' in window)) {
        console.warn('Push messaging is not supported in this browser.');
        return;
    }

    try {
        const registration = await navigator.serviceWorker.register('/service-worker.js');
        console.log('Service Worker Registered');

        await initPush();
    } catch (err) {
        console.error('Service Worker registration failed:', err);
    }
}

/**
 * Request permission and trigger subscription
 */
const initPush = async () => {
    // Request permission
    const permission = await Notification.requestPermission();

    if (permission !== 'granted') {
        console.warn('Notification permission denied.');
        return;
    }

    await subscribeUser();
}

/**
 * Subscribe the user to the Push Manager
 */
const subscribeUser = async () => {
    const registration = await navigator.serviceWorker.ready;

    // Check if a subscription already exists
    let pushSubscription = await registration.pushManager.getSubscription();

    if (!pushSubscription) {
        const subscribeOptions = {
            userVisibleOnly: true,
            applicationServerKey: urlBase64ToUint8Array(
                import.meta.env.VITE_VAPID_PUBLIC_KEY
            )
        };

        try {
            pushSubscription = await registration.pushManager.subscribe(subscribeOptions);
            console.log('New Subscription created.');
        } catch (err) {
            console.error('Failed to subscribe user:', err);
            return;
        }
    } else {
        console.log('User is already subscribed.');
    }

    // Send subscription to Laravel backend
    if (pushSubscription) {
        console.log('Received PushSubscription:', JSON.stringify(pushSubscription));
        await storePushSubscription(pushSubscription);
    }
}

export const storePushSubscription = async (pushSubscription) => {
    try {
        const response = await axios.post('/api/push', pushSubscription);
        console.log('Successfully stored subscription:', response.data);
    } catch (err) {
        console.error('Error storing subscription on server:', err);
    }
}

/**
 * Helper to convert VAPID key
 */
function urlBase64ToUint8Array(base64String) {
    if (!base64String) {
        console.error('VITE_VAPID_PUBLIC_KEY is missing from .env');
        return new Uint8Array();
    }
    const padding = '='.repeat((4 - base64String.length % 4) % 4);
    const base64 = (base64String + padding).replace(/-/g, '+').replace(/_/g, '/');
    const rawData = window.atob(base64);
    return Uint8Array.from([...rawData].map((char) => char.charCodeAt(0)));
}