// ── Firebase Messaging (background push for Android PWA) ──────────────────────
// Dynamically fetch Firebase config from backend to ensure consistency
importScripts('https://www.gstatic.com/firebasejs/10.14.1/firebase-app-compat.js');
importScripts('https://www.gstatic.com/firebasejs/10.14.1/firebase-messaging-compat.js');

let FIREBASE_CONFIG = null;
let VAPID_KEY = null;

// Fetch Firebase config and initialise messaging
let messaging = null;
let firebaseConfigPromise = fetch('/api/push/firebase-config')
  .then(res => res.json())
  .then(config => {
    FIREBASE_CONFIG = {
      apiKey: config.apiKey,
      authDomain: config.authDomain || `${config.projectId}.firebaseapp.com`,
      projectId: config.projectId,
      storageBucket: config.storageBucket || `${config.projectId}.firebasestorage.app`,
      messagingSenderId: config.messagingSenderId,
      appId: config.appId
    };
    VAPID_KEY = config.vapidKey;
    
    if (FIREBASE_CONFIG.apiKey) {
      firebase.initializeApp(FIREBASE_CONFIG);
      messaging = firebase.messaging();
      console.log('[SW] Firebase initialized with dynamic config');
    }
  })
  .catch(err => {
    console.warn('[SW] Failed to fetch Firebase config:', err);
  });

// ── Cache ─────────────────────────────────────────────────────────────────────
const CACHE_NAME = 'rosterchirp-v1';
const STATIC_ASSETS = ['/'];

self.addEventListener('install', (event) => {
  event.waitUntil(
    caches.open(CACHE_NAME).then((cache) => cache.addAll(STATIC_ASSETS))
  );
  self.skipWaiting();
});

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

self.addEventListener('fetch', (event) => {
  const url = event.request.url;
  if (url.includes('/api/') || url.includes('/socket.io/') || url.includes('/manifest.json')) {
    return;
  }
  event.respondWith(
    fetch(event.request).catch(() => caches.match(event.request))
  );
});

// ── Badge counter ─────────────────────────────────────────────────────────────
let badgeCount = 0;

function showRosterChirpNotification(data) {
  console.log('[SW] showRosterChirpNotification:', JSON.stringify(data));
  badgeCount++;
  if (self.navigator?.setAppBadge) self.navigator.setAppBadge(badgeCount).catch(() => {});

  return self.registration.showNotification(data.title || 'New Message', {
    body:    data.body || '',
    icon:    '/icons/icon-192.png',
    badge:   '/icons/icon-192-maskable.png',
    data:    { url: data.url || '/' },
    tag:     data.groupId ? `rosterchirp-group-${data.groupId}` : 'rosterchirp-message',
    renotify: true,
    vibrate:  [200, 100, 200],
  });
}

// ── FCM background messages ───────────────────────────────────────────────────
// Wait for Firebase config to be loaded before setting up message handler
firebaseConfigPromise.then(() => {
  if (messaging) {
    messaging.onBackgroundMessage((payload) => {
      console.log('[SW] onBackgroundMessage received, data:', JSON.stringify(payload.data));
      return showRosterChirpNotification(payload.data || {});
    });
  } else {
    console.warn('[SW] Firebase messaging not initialised — push notifications disabled');
  }
});

// ── Raw push event (fallback for Android) ─────────────────────────────────────
// Android Chrome sometimes doesn't properly trigger Firebase's onBackgroundMessage
// This fallback ensures notifications are displayed even if Firebase SDK fails
self.addEventListener('push', (event) => {
  console.log('[SW] push event received, hasData:', !!event.data, 'text:', event.data?.text?.()?.slice(0, 120));
  
  // Try to handle the push event directly as a fallback
  if (event.data) {
    try {
      const data = event.data.json();
      console.log('[SW] Push data parsed:', JSON.stringify(data));
      
      // If this is a Firebase message with data payload, show notification
      if (data.data || (data.title && data.body)) {
        const notificationData = data.data || data;
        return showRosterChirpNotification(notificationData);
      }
    } catch (e) {
      console.warn('[SW] Failed to parse push data:', e);
      // Try to show a basic notification with the raw text
      const text = event.data.text();
      if (text) {
        return self.registration.showNotification('RosterChirp', {
          body: text.slice(0, 100),
          icon: '/icons/icon-192.png',
          badge: '/icons/icon-192-maskable.png',
          tag: 'rosterchirp-fallback',
        });
      }
    }
  }
});

// ── Notification click ────────────────────────────────────────────────────────
self.addEventListener('notificationclick', (event) => {
  event.notification.close();
  badgeCount = 0;
  if (self.navigator?.clearAppBadge) self.navigator.clearAppBadge().catch(() => {});
  event.waitUntil(
    clients.matchAll({ type: 'window', includeUncontrolled: true }).then((clientList) => {
      const url = event.notification.data?.url || '/';
      for (const client of clientList) {
        if (client.url.includes(self.location.origin) && 'focus' in client) {
          client.focus();
          return;
        }
      }
      return clients.openWindow(url);
    })
  );
});

// ── Badge control messages from main thread ───────────────────────────────────
self.addEventListener('message', (event) => {
  if (event.data?.type === 'CLEAR_BADGE') {
    badgeCount = 0;
    if (self.navigator?.clearAppBadge) self.navigator.clearAppBadge().catch(() => {});
  }
  if (event.data?.type === 'SET_BADGE') {
    badgeCount = event.data.count || 0;
    if (self.navigator?.setAppBadge) {
      if (badgeCount > 0) {
        self.navigator.setAppBadge(badgeCount).catch(() => {});
      } else {
        self.navigator.clearAppBadge().catch(() => {});
      }
    }
  }
});