/* Baustelle PWA Service Worker.
 * Cache-Strategie:
 *   - App-Shell (HTML/CSS/JS): cache-first, network update
 *   - API-Calls: network-first, kein offline-cache (da auth-pflichtig)
 */

const CACHE = 'baustelle-v5';
const SHELL = [
    './',
    './index.html',
    './share.html',
    './app.css',
    './app.js',
    './manifest.webmanifest',
    './lib/idb.js',
    './lib/api.js',
    './lib/offline.js',
    './lib/router.js',
    './icons/icon-192.png',
    './icons/icon-512.png',
];

// Web Share Target: eingehende POSTs an share.html abfangen und in IDB zwischenspeichern
async function handleShareTarget(request) {
    const fd = await request.formData();
    const files = fd.getAll('photos');
    if (files.length) {
        const db = await new Promise((res, rej) => {
            const req = indexedDB.open('baustelle-pwa-v1', 1);
            req.onupgradeneeded = () => {
                const d = req.result;
                if (!d.objectStoreNames.contains('kv')) d.createObjectStore('kv');
                if (!d.objectStoreNames.contains('queue')) d.createObjectStore('queue', { keyPath: 'id', autoIncrement: true });
            };
            req.onsuccess = () => res(req.result);
            req.onerror = () => rej(req.error);
        });
        const tx = db.transaction('kv', 'readwrite');
        tx.objectStore('kv').put(files.map(f => ({ name: f.name, type: f.type, data: f })), 'shared_files');
        await new Promise(res => tx.oncomplete = res);
    }
    return Response.redirect('./share.html', 303);
}

self.addEventListener('install', (e) => {
    e.waitUntil(caches.open(CACHE).then(c => c.addAll(SHELL).catch(() => null)));
    self.skipWaiting();
});

self.addEventListener('activate', (e) => {
    e.waitUntil(
        caches.keys().then(keys => Promise.all(
            keys.filter(k => k !== CACHE).map(k => caches.delete(k))
        ))
    );
    self.clients.claim();
});

self.addEventListener('fetch', (e) => {
    const url = new URL(e.request.url);

    // Web Share Target: POST auf share.html abfangen
    if (e.request.method === 'POST' && url.pathname.endsWith('/share.html')) {
        e.respondWith(handleShareTarget(e.request));
        return;
    }

    // API-Requests: nicht cachen, durchreichen
    if (url.pathname.includes('/custom/bericht/api/')) {
        return; // default network
    }

    // App-Shell: cache-first
    if (e.request.method === 'GET' && url.origin === location.origin) {
        e.respondWith(
            caches.match(e.request).then(hit => {
                if (hit) {
                    // Background-Update
                    fetch(e.request).then(r => {
                        if (r.ok) caches.open(CACHE).then(c => c.put(e.request, r.clone()));
                    }).catch(() => null);
                    return hit;
                }
                return fetch(e.request).then(r => {
                    if (r.ok) {
                        const clone = r.clone();
                        caches.open(CACHE).then(c => c.put(e.request, clone));
                    }
                    return r;
                });
            })
        );
    }
});