const CACHE_NAME = 'iistwin-pwa-v13';
const STATIC_ASSETS = [
  '/',
  '/index.html',
  '/manifest.json',
  '/favicon.svg',
  // Self-hosted шрифты — precache, чтобы PWA офлайн рендерился без FOUT/fallback
  // (имена файлов должны совпадать с @font-face в client/src/index.css)
  '/fonts/inter-var-latin.woff2',
  '/fonts/inter-var-latin-ext.woff2',
  '/fonts/inter-var-cyrillic.woff2',
  '/fonts/inter-var-cyrillic-ext.woff2',
  '/fonts/dm-mono-400-latin.woff2',
  '/fonts/dm-mono-400-latin-ext.woff2',
  '/fonts/dm-mono-500-latin.woff2',
  '/fonts/dm-mono-500-latin-ext.woff2'
];

// Активный чат, о котором сообщает клиент через postMessage.
// Используется для подавления push-уведомлений, когда пользователь уже
// смотрит в соответствующий чат.
let activeChat = null; // { type: 'messenger'|'task', id: number, visible: boolean, updatedAt: number }

// ── IndexedDB helpers (mirrors offlineQueue.ts schema, must stay in sync) ────
// Schema history:
//  v1 – `queue` store (keyPath: id, index: enqueuedAt)
//  v2 – no structural change (conflictStatus field added to queue items)
//  v3 – `inbox-cache`, `task-cache`, `form-cache` added for PWA offline mode
//  v4 – `directory-cache` added for offline справочник lookups
//  v5 – `attachment-queue` для фоновой отправки сообщений с файлами
//  v6 – synced-* stores для офлайн-кэша форм/задач/справочников
//  v7 – queue token/orgId fields nullable for cookie-based auth
const IDB_NAME = 'iistwin-offline';
const IDB_VERSION = 7;
const IDB_STORE = 'queue';

function openQueueDB() {
  return new Promise((resolve, reject) => {
    const req = indexedDB.open(IDB_NAME, IDB_VERSION);
    req.onupgradeneeded = (e) => {
      const db = e.target.result;
      // v1
      if (!db.objectStoreNames.contains('queue')) {
        const store = db.createObjectStore('queue', { keyPath: 'id' });
        store.createIndex('enqueuedAt', 'enqueuedAt', { unique: false });
      }
      // v2: no structural change
      // v3
      if (!db.objectStoreNames.contains('inbox-cache')) {
        db.createObjectStore('inbox-cache', { keyPath: 'userId' });
      }
      if (!db.objectStoreNames.contains('task-cache')) {
        db.createObjectStore('task-cache', { keyPath: 'taskId' });
      }
      if (!db.objectStoreNames.contains('form-cache')) {
        db.createObjectStore('form-cache', { keyPath: 'formId' });
      }
      // v4
      if (!db.objectStoreNames.contains('directory-cache')) {
        db.createObjectStore('directory-cache', { keyPath: 'tableId' });
      }
      // v5: attachment-queue для фоновой отправки сообщений с файлами
      if (!db.objectStoreNames.contains('attachment-queue')) {
        const aqStore = db.createObjectStore('attachment-queue', { keyPath: 'id' });
        aqStore.createIndex('enqueuedAt', 'enqueuedAt', { unique: false });
      }
      // v6/v7: synced-* stores для офлайн-кэша форм и задач
      const syncedStoreNames = [
        'synced-forms',
        'synced-tasks',
        'synced-task-field-values',
        'synced-data-tables',
        'synced-data-table-rows',
        'synced-automations',
        'sync-subscriptions',
        'sync-meta',
        'pending-mutations',
        'synced-users',
      ];
      for (const name of syncedStoreNames) {
        if (!db.objectStoreNames.contains(name)) {
          if (name === 'synced-task-field-values') {
            const store = db.createObjectStore(name, { keyPath: 'id' });
            store.createIndex('taskId', 'taskId', { unique: false });
          } else if (name === 'synced-data-table-rows') {
            const store = db.createObjectStore(name, { keyPath: 'id' });
            store.createIndex('tableId', 'tableId', { unique: false });
          } else {
            db.createObjectStore(name, { keyPath: 'id' });
          }
        }
      }
    };
    req.onsuccess = () => resolve(req.result);
    req.onerror = () => reject(req.error);
  });
}

function getAllQueueItems(db) {
  return new Promise((resolve, reject) => {
    const tx = db.transaction(IDB_STORE, 'readonly');
    const req = tx.objectStore(IDB_STORE).index('enqueuedAt').getAll();
    req.onsuccess = () => resolve(req.result);
    req.onerror = () => reject(req.error);
  });
}

function removeQueueItem(db, id) {
  return new Promise((resolve, reject) => {
    const tx = db.transaction(IDB_STORE, 'readwrite');
    tx.objectStore(IDB_STORE).delete(id);
    tx.oncomplete = () => resolve();
    tx.onerror = () => reject(tx.error);
  });
}

function isSafeToDrop(url, method) {
  return method === 'POST' && /\/api\/messages\/\d+\/read$/.test(url);
}

function fetchWithTimeout(request, timeoutMs) {
  return new Promise((resolve, reject) => {
    const controller = new AbortController();
    const timer = setTimeout(() => controller.abort(), timeoutMs);
    fetch(request, { signal: controller.signal })
      .then((response) => {
        clearTimeout(timer);
        resolve(response);
      })
      .catch((error) => {
        clearTimeout(timer);
        reject(error);
      });
  });
}

const ATTACHMENT_STORE = 'attachment-queue';

function getAllAttachmentItems(db) {
  return new Promise((resolve, reject) => {
    const tx = db.transaction(ATTACHMENT_STORE, 'readonly');
    const req = tx.objectStore(ATTACHMENT_STORE).index('enqueuedAt').getAll();
    req.onsuccess = () => resolve(req.result);
    req.onerror = () => reject(req.error);
  });
}

function removeAttachmentItem(db, id) {
  return new Promise((resolve, reject) => {
    const tx = db.transaction(ATTACHMENT_STORE, 'readwrite');
    tx.objectStore(ATTACHMENT_STORE).delete(id);
    tx.oncomplete = () => resolve();
    tx.onerror = () => reject(tx.error);
  });
}

function updateAttachmentItem(db, item) {
  return new Promise((resolve, reject) => {
    const tx = db.transaction(ATTACHMENT_STORE, 'readwrite');
    tx.objectStore(ATTACHMENT_STORE).put(item);
    tx.oncomplete = () => resolve();
    tx.onerror = () => reject(tx.error);
  });
}

async function uploadFileFromSW(file) {
  const formData = new FormData();
  formData.append('file', file.blob, file.name);
  const res = await fetch('/api/upload', {
    method: 'POST',
    body: formData,
    credentials: 'include',
  });
  if (!res.ok) {
    const err = await res.json().catch(() => ({}));
    throw new Error(err.error || `Upload failed: ${res.status}`);
  }
  return res.json();
}

async function sendMessageFromSW(item, attachments) {
  const url = item.type === 'messenger'
    ? `/api/messenger/conversations/${item.targetId}/messages`
    : `/api/tasks/${item.targetId}/messages`;

  const payload = {
    message: item.message || '',
    attachments,
  };

  if (item.replyToId || item.replyToMessageId) {
    if (item.type === 'messenger') {
      payload.replyToId = item.replyToId || item.replyToMessageId;
    } else {
      payload.replyToMessageId = item.replyToMessageId || item.replyToId;
    }
  }

  if (item.mentionedUserIds && item.mentionedUserIds.length > 0) {
    payload.mentionedUserIds = item.mentionedUserIds;
  }
  if (item.mentionedBotIds && item.mentionedBotIds.length > 0) {
    payload.mentionedBotIds = item.mentionedBotIds;
  }

  const res = await fetch(url, {
    method: 'POST',
    headers: { 'Content-Type': 'application/json' },
    body: JSON.stringify(payload),
    credentials: 'include',
  });

  if (!res.ok) {
    const err = await res.json().catch(() => ({}));
    throw new Error(err.error || `Send failed: ${res.status}`);
  }
  return res.json();
}

/** Replay attachment queue directly from the SW. */
async function replayAttachmentQueueFromSW() {
  let db;
  try {
    db = await openQueueDB();
  } catch {
    console.log('[SW] Cannot open IndexedDB for attachment replay');
    return;
  }
  const items = await getAllAttachmentItems(db);
  console.log(`[SW] Replaying ${items.length} attachment operation(s) from SW`);

  for (const item of items) {
    // Skip items already in error state (need user action or app open to retry)
    if (item.status === 'error') {
      console.log(`[SW] Skipping attachment ${item.id} — error state`);
      continue;
    }

    try {
      const attachments = [];
      for (const file of item.files || []) {
        const data = await uploadFileFromSW(file);
        attachments.push({
          url: data.url,
          name: data.name,
          size: data.size,
          mimeType: file.type || undefined,
        });
      }
      await sendMessageFromSW(item, attachments);
      await removeAttachmentItem(db, item.id);
      console.log(`[SW] Replayed attachment ${item.id} → success`);
    } catch (err) {
      console.log(`[SW] Attachment replay error ${item.id}:`, err.message);
      // Network errors: stop and retry later
      // 401/403: mark error (session may be expired, need app open)
      // 4xx validation errors: mark error
      // 5xx/429: stop and retry later
      if (err.message && (err.message.includes('401') || err.message.includes('403'))) {
        item.status = 'error';
        item.error = 'Требуется повторный вход';
        await updateAttachmentItem(db, item);
        continue;
      }
      if (err.message && /\b4\d\d\b/.test(err.message)) {
        item.status = 'error';
        item.error = err.message;
        await updateAttachmentItem(db, item);
        continue;
      }
      // Transient error — stop replay, next sync will retry
      break;
    }
  }
}

/** Replay the offline queue directly from the SW (used when no window clients exist). */
async function replayQueueFromSW() {
  let db;
  try {
    db = await openQueueDB();
  } catch {
    console.log('[SW] Cannot open IndexedDB for replay');
    return;
  }
  const items = await getAllQueueItems(db);
  console.log(`[SW] Replaying ${items.length} queued request(s) from SW`);
  for (const item of items) {
    try {
      const headers = { 'Content-Type': 'application/json' };
      const res = await fetch(item.url, {
        method: item.method,
        headers,
        body: item.body ?? undefined,
        credentials: 'include',
      });
      if (res.ok || (res.status >= 400 && res.status < 500 && res.status !== 429 && isSafeToDrop(item.url, item.method))) {
        // Success or safe permanent client error — remove from queue
        await removeQueueItem(db, item.id);
        console.log(`[SW] Replayed ${item.method} ${item.url} → ${res.status}`);
      } else {
        // Server error, 429, or non-safe 4xx — stop and let the app handle it
        console.log(`[SW] Replay stopped at ${item.method} ${item.url} → ${res.status}`);
        break;
      }
    } catch {
      // Network error during SW replay — stop
      console.log(`[SW] Replay network error at ${item.method} ${item.url}`);
      break;
    }
  }
}

// ── Lifecycle ─────────────────────────────────────────────────────────────────

self.addEventListener('install', (event) => {
  console.log('[SW] Installing service worker...');
  event.waitUntil(
    caches.open(CACHE_NAME).then((cache) => {
      console.log('[SW] Caching static assets');
      return cache.addAll(STATIC_ASSETS);
    })
  );
  self.skipWaiting();
});

self.addEventListener('activate', (event) => {
  console.log('[SW] Activating service worker...');
  event.waitUntil(
    caches.keys().then((cacheNames) => {
      return Promise.all(
        cacheNames
          .filter((name) => name !== CACHE_NAME)
          .map((name) => {
            console.log('[SW] Deleting old cache:', name);
            return caches.delete(name);
          })
      );
    })
  );
  self.clients.claim();
});

async function handleShareTarget(request) {
  try {
    const formData = await request.formData();
    const files = formData.getAll('media');
    const title = formData.get('title') || '';
    const text = formData.get('text') || '';
    const url = formData.get('url') || '';

    const cache = await caches.open('share-target-files');
    await cache.put('/share-target/data', new Response(JSON.stringify({
      title: String(title),
      text: String(text) + (url ? '\n' + url : ''),
      fileCount: files.length,
      fileNames: files.map(f => (f instanceof File ? f.name : 'file')),
      timestamp: Date.now(),
    }), { headers: { 'Content-Type': 'application/json' } }));

    for (let i = 0; i < files.length; i++) {
      const file = files[i];
      if (file instanceof Blob) {
        await cache.put(`/share-target/file/${i}`, new Response(file, {
          headers: { 'Content-Type': file.type || 'application/octet-stream' }
        }));
      }
    }
  } catch (err) {
    console.error('[SW] Share target error:', err);
  }
  return Response.redirect('/share-target?shared=1', 303);
}

self.addEventListener('fetch', (event) => {
  if (event.request.url.includes('/share-target') && event.request.method === 'POST') {
    event.respondWith(handleShareTarget(event.request));
    return;
  }

  if (event.request.method !== 'GET') return;

  const url = new URL(event.request.url);

  // Skip API requests
  if (url.pathname.startsWith('/api/')) return;

  // Navigation requests (page loads): network-first with a short timeout,
  // falling back to the cached shell. This guarantees that users see the
  // latest build when they are online, while still keeping the app usable
  // during cold PWA starts or flaky connections.
  if (event.request.mode === 'navigate') {
    event.respondWith(
      fetchWithTimeout(event.request, 3000)
        .then(async (networkResponse) => {
          if (networkResponse.status === 200) {
            const clone = networkResponse.clone();
            const cache = await caches.open(CACHE_NAME);
            await cache.put('/index.html', clone);
          }
          return networkResponse;
        })
        .catch(async () => {
          const cached = await caches.match('/index.html');
          if (cached) return cached;
          const rootFallback = await caches.match('/');
          if (rootFallback) return rootFallback;
          return new Response('Offline', { status: 503, statusText: 'Service Unavailable' });
        })
    );
    return;
  }

  event.respondWith(
    fetchWithTimeout(event.request, 5000)
      .then((response) => {
        if (response.status === 200) {
          const responseClone = response.clone();
          caches.open(CACHE_NAME).then((cache) => {
            cache.put(event.request, responseClone);
          });
        }
        return response;
      })
      .catch(() => caches.match(event.request))
  );
});

// ── Background Sync ───────────────────────────────────────────────────────────

self.addEventListener('sync', (event) => {
  if (event.tag === 'offline-queue') {
    console.log('[SW] Background sync triggered: offline-queue');
    event.waitUntil(
      clients.matchAll({ type: 'window', includeUncontrolled: false }).then(async (clientList) => {
        if (clientList.length > 0) {
          // App is open — tell it to handle sync (it has access to React Query cache)
          for (const client of clientList) {
            client.postMessage({ type: 'TRIGGER_SYNC' });
          }
        } else {
          // App is closed — replay queue directly from SW
          await replayQueueFromSW();
        }
      })
    );
  }

  if (event.tag === 'attachment-queue') {
    console.log('[SW] Background sync triggered: attachment-queue');
    event.waitUntil(
      clients.matchAll({ type: 'window', includeUncontrolled: false }).then(async (clientList) => {
        if (clientList.length > 0) {
          // App is open — let the app handle it so React Query cache is updated
          for (const client of clientList) {
            client.postMessage({ type: 'TRIGGER_ATTACHMENT_SYNC' });
          }
        } else {
          // App is closed — replay attachment queue directly from SW
          await replayAttachmentQueueFromSW();
        }
      })
    );
  }

  if (event.tag === 'offline-sync') {
    console.log('[SW] Background sync triggered: offline-sync');
    event.waitUntil(
      clients.matchAll({ type: 'window', includeUncontrolled: false }).then((clientList) => {
        if (clientList.length > 0) {
          // App is open — let the full sync engine run in the window context
          for (const client of clientList) {
            client.postMessage({ type: 'TRIGGER_SYNC' });
          }
        }
        // When the app is closed we cannot run the full sync engine (it needs
        // React Query and the authenticated fetch layer). The queued mutations
        // will be replayed by the offline-queue tag instead.
      })
    );
  }
});

// ── Push notifications ────────────────────────────────────────────────────────

async function hasVisibleClient() {
  const clientList = await clients.matchAll({ type: 'window', includeUncontrolled: true });
  return clientList.some((client) => client.visibilityState === 'visible');
}

async function sendToForegroundClients(payload) {
  const clientList = await clients.matchAll({ type: 'window', includeUncontrolled: true });
  for (const client of clientList) {
    client.postMessage({ type: 'FOREGROUND_NOTIFICATION', payload });
  }
}

function shouldSuppressPushForActiveChat(payload) {
  if (!activeChat || !activeChat.visible) return false;

  // Игнорируем устаревшие записи.
  const maxAgeMs = 60 * 1000;
  if (!activeChat.updatedAt || Date.now() - activeChat.updatedAt > maxAgeMs) return false;

  const nestedType = payload.data?.type;

  if (nestedType === 'messenger' && activeChat.type === 'messenger') {
    return parseInt(payload.data?.conversationId, 10) === activeChat.id;
  }

  if ((nestedType === 'chat' || payload.type === 'chat') && activeChat.type === 'task') {
    return parseInt(payload.data?.taskId || payload.taskId, 10) === activeChat.id;
  }

  return false;
}

self.addEventListener('push', (event) => {
  console.log('[SW] Push notification received');

  let data = {
    title: 'Уведомление',
    body: 'Новое сообщение',
    icon: '/icons/icon-192x192.png',
    url: '/',
  };

  if (event.data) {
    try {
      data = { ...data, ...event.data.json() };
    } catch {
      data.body = event.data.text();
    }
  }

  // Silent sync trigger: do not show a notification, just request a background sync.
  // Support both the new top-level type and the old nested data.type shape.
  if (data.type === 'SYNC_NEEDED' || data.data?.type === 'SYNC_NEEDED') {
    event.waitUntil(
      self.registration.sync
        ? self.registration.sync.register('offline-sync').catch(() => {})
        : Promise.resolve()
    );
    return;
  }

  // Подавляем push, если пользователь уже смотрит в этот чат на активной вкладке.
  if (shouldSuppressPushForActiveChat(data)) {
    console.log('[SW] Push suppressed for active chat:', activeChat);
    return;
  }

  event.waitUntil(
    hasVisibleClient().then((visible) => {
      if (visible) {
        // Active tab gets an in-app toast instead of a system notification.
        return sendToForegroundClients(data);
      }

      const options = {
        body: data.body || data.message || '',
        icon: data.icon || '/icons/icon-192x192.png',
        badge: '/icons/icon-192x192.png',
        vibrate: [100, 50, 100],
        data: { url: data.url || data.click_action || '/', ...data },
        actions: data.actions || [],
        // Keep the notification on screen until the user interacts with it
        // when the tab is not active.
        requireInteraction: true,
        // Use a unique tag per task so multiple task notifications stack instead of
        // replacing each other, and avoid renotify which can suppress display on some OSs.
        tag: data.tag || (data.taskId ? `task-${data.taskId}` : `notif-${Date.now()}`),
      };

      return self.registration.showNotification(data.title, options);
    })
  );
});

async function openOrFocusChat(url) {
  const absoluteUrl = new URL(url, self.location.origin).href;
  console.log('[SW] openOrFocusChat:', absoluteUrl);

  try {
    // Ищем любые окна (включая неподконтрольные) — focus работает и на них,
    // а navigate может не сработать на uncontrolled, поэтому оборачиваем в try/catch.
    const clientList = await clients.matchAll({ type: 'window', includeUncontrolled: true });
    console.log('[SW] clients found:', clientList.length);

    // Сначала ищем клиент с уже открытым этим URL — просто фокусируем.
    for (const client of clientList) {
      try {
        if (client.url === absoluteUrl && 'focus' in client) {
          console.log('[SW] focusing existing client with same URL');
          return await client.focus();
        }
      } catch (err) {
        console.error('[SW] focus same-url client error:', err);
      }
    }

    // Затем пытаемся навигировать любой доступный клиент.
    for (const client of clientList) {
      try {
        if ('focus' in client) {
          console.log('[SW] navigating client to', absoluteUrl);
          await client.navigate(absoluteUrl);
          return await client.focus();
        }
      } catch (err) {
        console.error('[SW] navigate client error:', err);
      }
    }

    // Нет подходящих клиентов — открываем новое окно/вкладку.
    console.log('[SW] opening new window');
    const newClient = await clients.openWindow(absoluteUrl);
    if (newClient && 'focus' in newClient) {
      return await newClient.focus();
    }
    return newClient;
  } catch (err) {
    console.error('[SW] openOrFocusChat fatal error:', err);
    // Последний fallback — всё равно пытаемся открыть окно.
    return clients.openWindow(absoluteUrl);
  }
}

async function markNotificationRead(data) {
  try {
    // Поддерживаем оба формата: type на верхнем уровне и вложенный data.type
    const type = data?.type || data?.data?.type;
    const messageId = data?.messageId || data?.data?.messageId;
    const conversationId = data?.conversationId || data?.data?.conversationId;

    if (type === 'chat' && messageId) {
      await fetch(`/api/messages/${messageId}/read`, {
        method: 'POST',
        credentials: 'include',
      });
      console.log('[SW] Marked chat message as read:', messageId);
    } else if (type === 'messenger' && conversationId) {
      await fetch(`/api/messenger/conversations/${conversationId}/read`, {
        method: 'POST',
        credentials: 'include',
      });
      console.log('[SW] Marked messenger conversation as read:', conversationId);
    }
  } catch (err) {
    console.error('[SW] Failed to mark notification as read:', err);
  }
}

self.addEventListener('notificationclick', (event) => {
  console.log('[SW] Notification clicked, action:', event.action);
  event.notification.close();

  const data = event.notification.data || {};
  console.log('[SW] Notification data:', JSON.stringify(data));

  // Fallback: если url отсутствует, пытаемся восстановить его из вложенного data.
  let urlToOpen = data.url || '/';
  if ((!data.url || data.url === '/') && data.data) {
    const nested = data.data;
    if (nested.type === 'chat' && nested.taskId && nested.formId) {
      urlToOpen = `/forms/${nested.formId}/tasks/${nested.taskId}${nested.isChat === 'true' ? '?tab=chat' : ''}`;
      console.log('[SW] Rebuilt url from nested data:', urlToOpen);
    } else if (nested.type === 'messenger' && nested.conversationId) {
      urlToOpen = `/chat/${nested.conversationId}`;
      console.log('[SW] Rebuilt url from nested data:', urlToOpen);
    }
  }

  if (event.action === 'read') {
    // "Прочитано": помечаем прочитанным и всё равно открываем задачу/чат, как ожидает пользователь.
    event.waitUntil(
      Promise.all([
        navigator.clearAppBadge ? navigator.clearAppBadge() : Promise.resolve(),
        markNotificationRead(data.data || data),
        openOrFocusChat(urlToOpen),
      ])
    );
    return;
  }

  // Body click or 'reply' action: open the linked task/chat and focus an existing tab if possible.
  event.waitUntil(
    Promise.all([
      navigator.clearAppBadge ? navigator.clearAppBadge() : Promise.resolve(),
      openOrFocusChat(urlToOpen),
    ])
  );
});

// ── Push subscription lifecycle ───────────────────────────────────────────────

self.addEventListener('pushsubscriptionchange', (event) => {
  console.log('[SW] Push subscription changed');
  event.waitUntil(
    clients.matchAll({ type: 'window', includeUncontrolled: true }).then((clientList) => {
      if (clientList.length > 0) {
        // Ask the app to resubscribe and register the new subscription with the server.
        for (const client of clientList) {
          client.postMessage({ type: 'PUSH_SUBSCRIPTION_CHANGE', oldEndpoint: event.oldSubscription?.endpoint });
        }
      } else {
        // No open clients — we cannot fetch a new subscription without user interaction.
        // The next app start will detect the missing/expired subscription and re-register.
        console.log('[SW] No window clients to handle pushsubscriptionchange');
      }
    })
  );
});

self.addEventListener('message', (event) => {
  if (event.data?.type === 'SKIP_WAITING') {
    self.skipWaiting();
    return;
  }

  if (event.data?.type === 'ACTIVE_CHAT') {
    const payload = event.data?.payload || {};
    activeChat = {
      type: payload.type,
      id: payload.id,
      visible: !!payload.visible,
      updatedAt: Date.now(),
    };
    return;
  }

  if (event.data?.type === 'CLEAR_ACTIVE_CHAT') {
    activeChat = null;
  }
});