// Service worker: makes the app installable, opens it without network (the
// saved chats open offline) and shows web pushes.
const CACHE = "shell-v1";
// The icon badge: `base` is the unread total the app saw last, `pending` the
// pushes since (the app resets both when it runs, src/ui/Main.svelte).
const BADGE = "badge";

// Navigations can update index.html while the worker script stays identical.
// Cache its referenced bundles before replacing the offline page; relying on
// script fetch events misses loads served by the browser's memory cache.
async function cacheShell(res) {
  const cache = await caches.open(CACHE);
  const html = await res.clone().text();
  const assets = [...html.matchAll(/(?:src|href)="(?:\.\/)?(assets\/[^"]+)"/g)].map(m => `./${m[1]}`);
  await Promise.all([...new Set(assets)].map(async asset => {
    if (await cache.match(asset, { ignoreVary: true })) return;
    const response = await fetch(asset);
    if (!response.ok) throw new Error("Could not cache app bundle.");
    await cache.put(asset, response);
  }));
  await cache.addAll(["./config.js", "./manifest.webmanifest", "./icon-192.png"]);
  await cache.put("./", res);
}

// Cache the app shell on install: the page plus the bundles it references.
// Waiting for the fetch handler isn't enough — Chromium serves repeat loads
// from its memory cache, which bypasses the service worker.
self.addEventListener("install", (event) => {
  event.waitUntil(
    (async () => {
      const res = await fetch("./", { cache: "no-cache" });
      if (!res.ok) throw new Error("Could not cache app page.");
      await cacheShell(res);
    })()
      .catch((err) => console.warn("precache failed", err))
      .then(() => self.skipWaiting()),
  );
});

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

self.addEventListener("fetch", (event) => {
  const req = event.request;
  const url = new URL(req.url);
  // Only our own static files; uploads, the websocket and anything
  // cross-origin go straight to the network.
  if (req.method !== "GET" || url.origin !== self.location.origin) return;

  // Hashed build assets never change: cache first. ignoreVary: module scripts are
  // requested with an Origin header, the precache request had none.
  if (url.pathname.includes("/assets/")) {
    const result = caches.match(req, { ignoreVary: true }).then(hit =>
      hit ? { res: hit, cached: true } : fetch(req).then(res => ({ res, cached: false })),
    );
    event.waitUntil(result.then(({ res, cached }) => {
      if (!cached && res.ok) {
        const copy = res.clone();
        return caches.open(CACHE).then(c => c.put(req, copy));
      }
    }).catch(() => {}));
    event.respondWith(result.then(({ res }) => res));
    return;
  }

  // The page, config.js, manifest and icons: network first, so a deploy is
  // picked up right away; the cached copy only when offline.
  const response = fetch(req);
  // Keep caching alive without holding the page response behind bundle/icon
  // downloads or storage writes. Register waitUntil during event dispatch.
  event.waitUntil(response.then(res => {
    if (!res.ok) return;
    const copy = res.clone();
    if (req.mode === "navigate") return cacheShell(copy);
    return caches.open(CACHE).then(c => c.put(req, copy));
  }).catch(err => console.warn("cache shell", err)));
  event.respondWith(
    response.catch(() =>
      caches.match(req.mode === "navigate" ? "./" : req, { ignoreVary: true }).then((hit) => hit || Response.error()),
    ),
  );
});

// Web push (PLAN.md, milestone 8): Prosody's mod_push2 sends each message
// that arrives while we're away, encrypted for this browser; the payload is
// the forwarded <message/> in an SCE envelope. iOS drops a subscription
// whose pushes show nothing, so every push shows a notification.
self.addEventListener("push", (event) => {
  event.waitUntil(showPush(event.data ? event.data.text() : ""));
});

const unescape = (s) =>
  s.replace(/&lt;/g, "<").replace(/&gt;/g, ">").replace(/&quot;/g, '"').replace(/&apos;/g, "'").replace(/&amp;/g, "&");

function attr(tag, name) {
  const m = new RegExp(`\\s${name}=(['"])(.*?)\\1`).exec(tag);
  return m ? unescape(m[2]) : "";
}

function parsePush(xml) {
  const tag = /<message\b[^>]*>/.exec(xml)?.[0] ?? "";
  const from = attr(tag, "from");
  const peer = from.split("/")[0];
  const name = peer.split("@")[0] || "0ff chat";
  // Calls: the caller hanging up replaces "Incoming call" (same tag).
  if (/<propose\b[^>]*urn:xmpp:jingle-message:0/.test(xml)) return { peer, title: name, body: "Incoming call", call: true };
  if (/<retract\b[^>]*urn:xmpp:jingle-message:0/.test(xml)) return { peer, title: name, body: "Missed call", call: true };
  const text = /<body(?:\s[^>]*)?>([\s\S]*?)<\/body>/.exec(xml);
  let body = text ? unescape(text[1]) : "New message";
  if (/jabber:x:oob/.test(xml)) body = "Attachment";
  if (attr(tag, "type") === "groupchat") return { peer, title: `${from.slice(from.indexOf("/") + 1)} in ${name}`, body };
  return { peer, title: name, body };
}

async function bumpBadge() {
  const cache = await caches.open(BADGE);
  const res = await cache.match("./badge-state");
  const state = res ? await res.json() : { base: 0, pending: 0 };
  state.pending += 1;
  await cache.put("./badge-state", new Response(JSON.stringify(state)));
  return state.base + state.pending;
}

async function showPush(xml) {
  const n = parsePush(xml);
  // The badge counts unread messages; calls are not among them.
  const count = n.call ? 0 : await bumpBadge().catch(() => 0);
  // Same tag as the in-page notifications, so one replaces the other. iOS
  // doesn't replace by tag, and mod_push2 pushes calls twice (archive and
  // session queue), so close the old one first (seen 2026-09-29).
  const tag = n.peer || "push";
  for (const old of await self.registration.getNotifications({ tag }).catch(() => [])) old.close();
  await self.registration.showNotification(n.title, {
    body: n.body.slice(0, 200),
    tag,
    icon: "icon-192.png",
    data: { hash: n.peer ? `#/chat/${encodeURIComponent(n.peer)}` : "" },
  });
  if (count) await self.navigator.setAppBadge?.(count).catch(() => {});
}

// Clicking a notification focuses the app and opens that chat.
self.addEventListener("notificationclick", (event) => {
  event.notification.close();
  const hash = event.notification.data?.hash ?? "";
  event.waitUntil(
    self.clients.matchAll({ type: "window", includeUncontrolled: true }).then((wins) => {
      const win = wins[0];
      if (win) {
        win.postMessage({ type: "open", hash });
        return win.focus();
      }
      return self.clients.openWindow(`./${hash}`);
    }),
  );
});