/// <reference lib="WebWorker" />

export type {};
declare const self: ServiceWorkerGlobalScope;

type SessionInfo = {
  accessToken: string;
  baseUrl: string;
};

/**
 * Store session per client (tab)
 */
const sessions = new Map<string, SessionInfo>();

const clientToResolve = new Map<string, (value: SessionInfo | undefined) => void>();
const clientToSessionPromise = new Map<string, Promise<SessionInfo | undefined>>();

async function cleanupDeadClients() {
  const activeClients = await self.clients.matchAll();
  const activeIds = new Set(activeClients.map((c) => c.id));

  Array.from(sessions.keys()).forEach((id) => {
    if (!activeIds.has(id)) {
      sessions.delete(id);
      clientToResolve.delete(id);
      clientToSessionPromise.delete(id);
    }
  });
}

function setSession(clientId: string, accessToken: any, baseUrl: any) {
  if (typeof accessToken === 'string' && typeof baseUrl === 'string') {
    sessions.set(clientId, { accessToken, baseUrl });
  } else {
    // Logout or invalid session
    sessions.delete(clientId);
  }

  const resolveSession = clientToResolve.get(clientId);
  if (resolveSession) {
    resolveSession(sessions.get(clientId));
    clientToResolve.delete(clientId);
    clientToSessionPromise.delete(clientId);
  }
}

function requestSession(client: Client): Promise<SessionInfo | undefined> {
  const promise =
    clientToSessionPromise.get(client.id) ??
    new Promise((resolve) => {
      clientToResolve.set(client.id, resolve);
      client.postMessage({ type: 'requestSession' });
    });

  if (!clientToSessionPromise.has(client.id)) {
    clientToSessionPromise.set(client.id, promise);
  }

  return promise;
}

async function requestSessionWithTimeout(
  clientId: string,
  timeoutMs = 3000
): Promise<SessionInfo | undefined> {
  const client = await self.clients.get(clientId);
  if (!client) return undefined;

  const sessionPromise = requestSession(client);

  const timeout = new Promise<undefined>((resolve) => {
    setTimeout(() => resolve(undefined), timeoutMs);
  });

  return Promise.race([sessionPromise, timeout]);
}

self.addEventListener('install', () => {
  self.skipWaiting();
});

self.addEventListener('activate', (event: ExtendableEvent) => {
  event.waitUntil(
    (async () => {
      await self.clients.claim();
      await cleanupDeadClients();
    })()
  );
});

/**
 * Receive session updates from clients
 */
self.addEventListener('message', (event: ExtendableMessageEvent) => {
  const client = event.source as Client | null;
  if (!client) return;

  const { type, accessToken, baseUrl } = event.data || {};

  if (type === 'setSession') {
    setSession(client.id, accessToken, baseUrl);
    cleanupDeadClients();
  }
});

const MEDIA_PATHS = ['/_matrix/client/v1/media/download', '/_matrix/client/v1/media/thumbnail'];

function mediaPath(url: string): boolean {
  try {
    const { pathname } = new URL(url);
    return MEDIA_PATHS.some((p) => pathname.startsWith(p));
  } catch {
    return false;
  }
}

function validMediaRequest(url: string, baseUrl: string): boolean {
  return MEDIA_PATHS.some((p) => {
    const validUrl = new URL(p, baseUrl);
    return url.startsWith(validUrl.href);
  });
}

function fetchConfig(token: string): RequestInit {
  return {
    headers: {
      Authorization: `Bearer ${token}`,
    },
    cache: 'default',
  };
}

self.addEventListener('fetch', (event: FetchEvent) => {
  const { url, method } = event.request;

  if (method !== 'GET' || !mediaPath(url)) return;

  const { clientId } = event;
  if (!clientId) return;

  const session = sessions.get(clientId);
  if (session) {
    if (validMediaRequest(url, session.baseUrl)) {
      event.respondWith(fetch(url, fetchConfig(session.accessToken)));
    }
    return;
  }

  event.respondWith(
    requestSessionWithTimeout(clientId).then((s) => {
      if (s && validMediaRequest(url, s.baseUrl)) {
        return fetch(url, fetchConfig(s.accessToken));
      }
      return fetch(event.request);
    })
  );
});

// --- Push Notifications ---

type PushPayload = {
  notification?: {
    event_id?: string;
    room_id?: string;
    sender?: string;
    sender_display_name?: string;
    room_name?: string;
    type?: string;
    content?: { body?: string; msgtype?: string };
    counts?: { unread?: number; missed_calls?: number };
    prio?: 'high' | 'low';
  };
};

async function hasVisibleClient(): Promise<boolean> {
  const clients = await self.clients.matchAll({ type: 'window', includeUncontrolled: true });
  return clients.some((c) => c.visibilityState === 'visible' && c.focused);
}

async function anySession(): Promise<SessionInfo | undefined> {
  const clients = await self.clients.matchAll({ type: 'window' });
  const existing = clients.map((c) => sessions.get(c.id)).find((s): s is SessionInfo => !!s);
  if (existing) return existing;
  if (clients.length > 0) {
    return requestSessionWithTimeout(clients[0].id);
  }
  return undefined;
}

// Fallback strings for when we can't fetch event content (offline / encrypted /
// no session). The main app runs i18next, but the SW is a separate context —
// we read navigator.language here and ship a small map for the locales we support.
type PushFallback = { brand: string; newMessage: string; encrypted: string };
const PUSH_FALLBACKS: Record<string, PushFallback> = {
  en: { brand: 'Vojo', newMessage: 'New message', encrypted: 'New encrypted message' },
  ru: { brand: 'Vojo', newMessage: 'Новое сообщение', encrypted: 'Новое зашифрованное сообщение' },
};

function pushFallback(): PushFallback {
  const lang = (typeof navigator !== 'undefined' ? navigator.language : 'en')
    .slice(0, 2)
    .toLowerCase();
  return PUSH_FALLBACKS[lang] ?? PUSH_FALLBACKS.en;
}

async function fetchEventDetails(
  session: SessionInfo,
  roomId: string,
  eventId: string
): Promise<{ title: string; body: string }> {
  const headers = { Authorization: `Bearer ${session.accessToken}` };
  const [evRes, nameRes] = await Promise.all([
    fetch(
      `${session.baseUrl}/_matrix/client/v3/rooms/${encodeURIComponent(roomId)}/event/${encodeURIComponent(eventId)}`,
      { headers }
    ),
    fetch(
      `${session.baseUrl}/_matrix/client/v3/rooms/${encodeURIComponent(roomId)}/state/m.room.name/`,
      { headers }
    ).catch(() => undefined),
  ]);

  const fb = pushFallback();
  let title = fb.brand;
  let body = fb.newMessage;

  if (evRes.ok) {
    const event = await evRes.json();
    if (event?.type === 'm.room.encrypted') {
      body = fb.encrypted;
    } else if (typeof event?.content?.body === 'string') {
      body = event.content.body.slice(0, 200);
    }
  }

  if (nameRes?.ok) {
    const json = await nameRes.json();
    if (typeof json?.name === 'string') title = json.name;
  }

  return { title, body };
}

self.addEventListener('push', (event: PushEvent) => {
  if (!event.data) return;

  event.waitUntil(
    (async () => {
      // Foreground dedup: in-app MessageNotifications handles visible clients
      if (await hasVisibleClient()) return;

      let payload: PushPayload = {};
      try {
        if (event.data) payload = event.data.json();
      } catch {
        payload = {};
      }

      const notif = payload.notification;
      const roomId = notif?.room_id;
      const eventId = notif?.event_id;

      // Defensive: if Sygnal sends a notification without event_id (e.g. unread-count-only
      // push, which `events_only: true` on the pusher should suppress but can slip through
      // if config drifts), skip it. We'd otherwise show a generic "New message" tied to no
      // room/event — clicking it goes nowhere useful.
      if (!eventId || !roomId) return;

      const fb = pushFallback();
      let title = notif?.room_name ?? fb.brand;
      let body = notif?.content?.body ?? fb.newMessage;

      const session = await anySession();
      if (session) {
        try {
          const details = await fetchEventDetails(session, roomId, eventId);
          title = details.title;
          body = details.body;
        } catch {
          // fall back to defaults
        }
      }

      await self.registration.showNotification(title, {
        body,
        icon: '/res/android/android-chrome-192x192.png',
        badge: '/res/android/android-chrome-96x96.png',
        tag: roomId,
        data: { roomId, eventId },
        renotify: true,
      } as NotificationOptions & { renotify?: boolean });
    })()
  );
});

self.addEventListener('notificationclick', (event) => {
  event.notification.close();
  const { roomId } = (event.notification.data as { roomId?: string }) ?? {};

  event.waitUntil(
    (async () => {
      const windows = await self.clients.matchAll({ type: 'window', includeUncontrolled: true });
      if (windows.length > 0) {
        const target = windows[0];
        await target.focus();
        target.postMessage({ type: 'notificationClick', roomId });
        return;
      }
      const path = roomId ? `/home/${encodeURIComponent(roomId)}/` : '/';
      await self.clients.openWindow(path);
    })()
  );
});

self.addEventListener('pushsubscriptionchange', ((event: ExtendableEvent) => {
  event.waitUntil(
    (async () => {
      const windows = await self.clients.matchAll({ type: 'window', includeUncontrolled: true });
      windows.forEach((c) => c.postMessage({ type: 'pushSubscriptionChange' }));
    })()
  );
}) as EventListener);