/**
 * ╔══════════════════════════════════════════════════════════╗
 * ║          SECUREVIEW SERVER  —  VERSION STABLE            ║
 * ║  WebRTC Surveillance · Base de données permanente        ║
 * ║  Cible: https://tafita1206-admin.hf.space                ║
 * ╚══════════════════════════════════════════════════════════╝
 *
 *  ARCHITECTURE DE ROUTAGE WEBRTC:
 *  ┌──────────┐   offer/ice(→client)   ┌──────────┐
 *  │  ADMIN   │ ─────────────────────► │  CLIENT  │
 *  │(adminSID)│ ◄───────────────────── │(clientId)│
 *  └──────────┘   answer/ice(→admin)   └──────────┘
 *
 *  Chaque admin reçoit un adminSessionId unique à la connexion.
 *  Ce SID est transmis au client dans incoming_call/webrtc_offer
 *  pour que le client sache vers quel admin renvoyer son answer.
 */

'use strict';

const express   = require('express');
const http      = require('http');
const WebSocket = require('ws');
const path      = require('path');
const cors      = require('cors');
const fs        = require('fs');

// ─────────────────────────────────────────────────
//  CONFIG
// ─────────────────────────────────────────────────
const PORT    = parseInt(process.env.PORT || '7860', 10);
const DB_FILE = path.join(__dirname, 'secureview_db.json');
const WS_PING_INTERVAL = 20000;   // ping ws toutes les 20s pour détecter déconnexions
const OFFLINE_TIMEOUT  = 90000;   // marquer offline après 90s sans heartbeat

// ─────────────────────────────────────────────────
//  EXPRESS
// ─────────────────────────────────────────────────
const app    = express();
const server = http.createServer(app);

app.use(cors({ origin: '*', methods: ['GET','POST','PUT','DELETE','OPTIONS'], allowedHeaders: '*' }));
app.use(express.json({ limit: '1mb' }));
app.use(express.static(path.join(__dirname, 'public')));

// Health check pour HuggingFace
app.get('/', (req, res) => res.json({ status: 'ok', service: 'SecureView', version: '2.0' }));

// ─────────────────────────────────────────────────
//  BASE DE DONNÉES JSON PERMANENTE
// ─────────────────────────────────────────────────
let db = { clients: {}, history: [] };

function dbLoad() {
  try {
    if (fs.existsSync(DB_FILE)) {
      const raw = fs.readFileSync(DB_FILE, 'utf8');
      const parsed = JSON.parse(raw);
      db.clients = parsed.clients || {};
      db.history  = parsed.history  || [];
      console.log(`[DB] Chargée: ${Object.keys(db.clients).length} compte(s)`);
    } else {
      dbSave();
      console.log('[DB] Nouvelle base créée');
    }
  } catch(e) {
    console.error('[DB] Erreur chargement:', e.message);
    db = { clients: {}, history: [] };
    dbSave();
  }
}

let dbSaveTimer = null;
function dbSave() {
  // Debounce: ne pas écrire plus d'une fois par seconde
  if (dbSaveTimer) return;
  dbSaveTimer = setTimeout(() => {
    dbSaveTimer = null;
    try { fs.writeFileSync(DB_FILE, JSON.stringify(db, null, 2), 'utf8'); }
    catch(e) { console.error('[DB] Erreur sauvegarde:', e.message); }
  }, 500);
}

function dbAddHistory(clientId, eventType, meta = {}) {
  db.history.push({
    id: Date.now() + Math.random(),
    client_id: clientId,
    event_type: eventType,
    timestamp: new Date().toISOString(),
    meta,
  });
  if (db.history.length > 5000) db.history = db.history.slice(-5000);
  dbSave();
}

dbLoad();

// ─────────────────────────────────────────────────
//  GÉNÉRATEUR D'IDs
// ─────────────────────────────────────────────────
function genId(prefix) {
  const ts  = Date.now().toString(36).toUpperCase();
  const rnd = Math.random().toString(36).substr(2, 6).toUpperCase();
  return `${prefix}_${ts}${rnd}`;
}

// ─────────────────────────────────────────────────
//  ÉTAT WEBSOCKET
//  ┌─ connectedClients : Map<clientId,    ws>
//  └─ adminSessions    : Map<adminSID,    ws>
//  ┌─ wsRegistry       : Map<ws, {type, id}>
// ─────────────────────────────────────────────────
const connectedClients = new Map();
const adminSessions    = new Map();
const ownerSessions    = new Map(); // Map<ownerSID, {ws, clientId}>
const wsRegistry       = new Map();

// ─────────────────────────────────────────────────
//  WEBSOCKET SERVER
// ─────────────────────────────────────────────────
const wss = new WebSocket.Server({ server, path: '/' });

wss.on('connection', (ws, req) => {
  const ip = (req.headers['x-forwarded-for'] || req.socket.remoteAddress || '?').split(',')[0].trim();

  // ── Ping/Pong pour détecter les connexions mortes ──
  ws._isAlive = true;
  ws.on('pong', () => { ws._isAlive = true; });

  ws.on('message', (raw) => {
    let msg;
    try { msg = JSON.parse(raw.toString()); }
    catch(e) { return; } // Ignorer JSON invalide

    handleMessage(ws, msg, ip);
  });

  ws.on('close', () => handleDisconnect(ws));
  ws.on('error', (e) => { console.error('[WS] Erreur:', e.message); });
});

// Ping toutes les 20s pour détecter clients fantômes
const pingInterval = setInterval(() => {
  wss.clients.forEach(ws => {
    if (!ws._isAlive) { ws.terminate(); return; }
    ws._isAlive = false;
    try { ws.ping(); } catch(e) {}
  });
}, WS_PING_INTERVAL);

wss.on('close', () => clearInterval(pingInterval));

// ─────────────────────────────────────────────────
//  GESTIONNAIRE DE MESSAGES
// ─────────────────────────────────────────────────
async function handleMessage(ws, msg, ip) {
  const { type } = msg;

  switch(type) {

    // ════════════════════════════════════════
    //  ENREGISTREMENT CLIENT
    // ════════════════════════════════════════
    case 'register_client': {
      const { clientId, registrationId } = msg;
      const client = db.clients[clientId];

      if (!client) {
        send(ws, { type: 'error', code: 'NOT_FOUND', message: 'Client ID inconnu. Créez un compte via /api/register' });
        return;
      }

      // Vérification Registration ID si fourni
      if (registrationId && client.registration_id !== registrationId) {
        send(ws, { type: 'error', code: 'AUTH_FAILED', message: 'Registration ID invalide' });
        return;
      }

      // Fermer ancienne connexion proprement
      const existing = connectedClients.get(clientId);
      if (existing && existing !== ws) {
        wsRegistry.delete(existing);
        try { existing.close(1000, 'New connection'); } catch(e) {}
      }

      connectedClients.set(clientId, ws);
      wsRegistry.set(ws, { type: 'client', id: clientId });

      // Mettre à jour statut
      client.status   = 'online';
      client.last_seen = new Date().toISOString();
      client.last_ip   = ip;
      dbSave();
      dbAddHistory(clientId, 'connect', { ip });

      send(ws, {
        type: 'registration_success',
        clientId,
        name: client.name,
        registrationId: client.registration_id,
      });

      notifyAdmins({
        type: 'client_connected',
        client: buildClientInfo(clientId),
      });

      console.log(`[WS] Client connecté: ${clientId} (${client.name}) depuis ${ip}`);
      break;
    }

    // ════════════════════════════════════════
    //  ENREGISTREMENT ADMIN
    // ════════════════════════════════════════
    case 'register_admin': {
      const adminSID = genId('ASID');

      adminSessions.set(adminSID, ws);
      wsRegistry.set(ws, { type: 'admin', id: adminSID });

      const clientList = buildClientList();

      send(ws, { type: 'admin_registered', adminSID });
      send(ws, { type: 'client_list', clients: clientList });

      console.log(`[WS] Admin connecté: ${adminSID} depuis ${ip}`);
      break;
    }

    // ════════════════════════════════════════
    //  ENREGISTREMENT OWNER (propriétaire)
    //  Le propriétaire se connecte avec son clientId
    //  Il reçoit le flux WebRTC de son propre appareil
    // ════════════════════════════════════════
    case 'register_owner': {
      const { clientId } = msg;
      if (!clientId || !db.clients[clientId]) {
        send(ws, { type: 'error', code: 'NOT_FOUND', message: 'Client ID inconnu' });
        return;
      }
      const ownerSID = genId('OSID');
      ownerSessions.set(ownerSID, { ws, clientId });
      wsRegistry.set(ws, { type: 'owner', id: ownerSID, clientId });

      send(ws, {
        type: 'owner_registered',
        ownerSID,
        clientId,
        client: buildClientInfo(clientId),
      });
      console.log(`[WS] Owner connecté: ${ownerSID} pour client(${clientId}) depuis ${ip}`);
      break;
    }

    // ════════════════════════════════════════
    //  CALL FROM OWNER → son propre client APK
    // ════════════════════════════════════════
    case 'owner_call_client': {
      const info = wsRegistry.get(ws);
      if (info?.type !== 'owner') return;
      const { mode } = msg;
      const { clientId } = info;
      const clientWs = connectedClients.get(clientId);
      if (!clientWs || clientWs.readyState !== WebSocket.OPEN) {
        send(ws, { type: 'call_error', clientId, message: 'Appareil hors ligne' });
        return;
      }
      send(clientWs, { type: 'incoming_call', mode: mode || 'manual', adminSID: info.id });
      send(ws, { type: 'call_initiated', clientId });
      console.log(`[CALL] Owner(${info.id}) → Client(${clientId}) mode=${mode}`);
      break;
    }

    // ════════════════════════════════════════
    //  WEBRTC OFFER (owner → son client APK)
    // ════════════════════════════════════════
    case 'owner_webrtc_offer': {
      const info = wsRegistry.get(ws);
      if (info?.type !== 'owner') return;
      const { offer } = msg;
      const { clientId, id: ownerSID } = info;
      const clientWs = connectedClients.get(clientId);
      if (!clientWs || clientWs.readyState !== WebSocket.OPEN) {
        send(ws, { type: 'rtc_error', message: `Appareil ${clientId} non connecté` });
        return;
      }
      send(clientWs, { type: 'webrtc_offer', offer, adminSID: ownerSID });
      console.log(`[RTC] Offer: owner(${ownerSID}) → client(${clientId})`);
      break;
    }

    // ════════════════════════════════════════
    //  ICE depuis owner → son client APK
    // ════════════════════════════════════════
    case 'owner_webrtc_ice': {
      const info = wsRegistry.get(ws);
      if (info?.type !== 'owner') return;
      const { candidate } = msg;
      const { clientId } = info;
      const clientWs = connectedClients.get(clientId);
      if (clientWs && clientWs.readyState === WebSocket.OPEN) {
        send(clientWs, { type: 'webrtc_ice', candidate });
      }
      break;
    }

    // ════════════════════════════════════════
    //  HEARTBEAT CLIENT
    // ════════════════════════════════════════
    case 'heartbeat': {
      const { clientId } = msg;
      if (db.clients[clientId]) {
        db.clients[clientId].status    = 'online';
        db.clients[clientId].last_seen = new Date().toISOString();
        dbSave();
      }
      send(ws, { type: 'heartbeat_ack' });
      break;
    }

    // ════════════════════════════════════════
    //  APPEL CLIENT (admin → client)
    // ════════════════════════════════════════
    case 'call_client': {
      const { clientId, mode } = msg;
      const info = wsRegistry.get(ws);
      if (info?.type !== 'admin') return;

      const adminSID  = info.id;
      const clientWs  = connectedClients.get(clientId);

      if (!clientWs || clientWs.readyState !== WebSocket.OPEN) {
        send(ws, { type: 'call_error', clientId, message: 'Client hors ligne ou introuvable' });
        return;
      }

      send(clientWs, { type: 'incoming_call', mode: mode || 'manual', adminSID });
      send(ws, { type: 'call_initiated', clientId, adminSID });
      console.log(`[CALL] Admin(${adminSID}) → Client(${clientId}) mode=${mode}`);
      break;
    }

    // ════════════════════════════════════════
    //  WEBRTC OFFER  (admin → client)
    // ════════════════════════════════════════
    case 'webrtc_offer': {
      const { targetClientId, offer, adminSID } = msg;
      const clientWs = connectedClients.get(targetClientId);

      if (!clientWs || clientWs.readyState !== WebSocket.OPEN) {
        send(ws, { type: 'rtc_error', message: `Client ${targetClientId} non connecté` });
        return;
      }

      send(clientWs, { type: 'webrtc_offer', offer, adminSID });
      console.log(`[RTC] Offer: admin(${adminSID}) → client(${targetClientId})`);
      break;
    }

    // ════════════════════════════════════════
    //  WEBRTC ANSWER  (client → admin ou owner)
    // ════════════════════════════════════════
    case 'webrtc_answer': {
      const { targetAdminSID, answer } = msg;

      // Chercher d'abord dans adminSessions
      const adminWs = adminSessions.get(targetAdminSID);
      if (adminWs && adminWs.readyState === WebSocket.OPEN) {
        send(adminWs, { type: 'webrtc_answer', answer });
        console.log(`[RTC] Answer: client → admin(${targetAdminSID})`);
        break;
      }

      // Sinon chercher dans ownerSessions
      const ownerEntry = ownerSessions.get(targetAdminSID);
      if (ownerEntry && ownerEntry.ws.readyState === WebSocket.OPEN) {
        send(ownerEntry.ws, { type: 'webrtc_answer', answer });
        console.log(`[RTC] Answer: client → owner(${targetAdminSID})`);
        break;
      }

      // Fallback: diffuser à tous les admins connectés
      console.warn(`[RTC] Dest(${targetAdminSID}) introuvable, broadcast fallback`);
      broadcastAdmins({ type: 'webrtc_answer', answer });
      break;
    }

    // ════════════════════════════════════════
    //  ICE CANDIDATE  (bidirectionnel)
    //  direction: 'to_client' | 'to_admin'
    // ════════════════════════════════════════
    case 'webrtc_ice': {
      const { direction, targetId, candidate } = msg;

      if (direction === 'to_client') {
        const dest = connectedClients.get(targetId);
        if (dest && dest.readyState === WebSocket.OPEN) {
          send(dest, { type: 'webrtc_ice', candidate });
        }
      } else if (direction === 'to_admin') {
        // Chercher admin d'abord
        const dest = adminSessions.get(targetId);
        if (dest && dest.readyState === WebSocket.OPEN) {
          send(dest, { type: 'webrtc_ice', candidate });
        } else {
          // Chercher owner ensuite
          const ownerEntry = ownerSessions.get(targetId);
          if (ownerEntry && ownerEntry.ws.readyState === WebSocket.OPEN) {
            send(ownerEntry.ws, { type: 'webrtc_ice', candidate });
          } else {
            broadcastAdmins({ type: 'webrtc_ice', candidate });
          }
        }
      }
      break;
    }

    // ════════════════════════════════════════
    //  FIN SESSION WEBRTC
    // ════════════════════════════════════════
    case 'webrtc_end': {
      const { targetId, direction } = msg;
      if (direction === 'to_client') {
        const dest = connectedClients.get(targetId);
        if (dest) send(dest, { type: 'webrtc_end' });
      } else {
        const destAdmin = adminSessions.get(targetId);
        if (destAdmin) { send(destAdmin, { type: 'webrtc_end' }); return; }
        const destOwner = ownerSessions.get(targetId);
        if (destOwner) send(destOwner.ws, { type: 'webrtc_end' });
      }
      break;
    }

    // FIN SESSION OWNER → client
    case 'owner_webrtc_end': {
      const info = wsRegistry.get(ws);
      if (info?.type !== 'owner') return;
      const clientWs = connectedClients.get(info.clientId);
      if (clientWs) send(clientWs, { type: 'webrtc_end' });
      break;
    }

    default:
      console.log('[WS] Message inconnu:', type);
  }
}

// ─────────────────────────────────────────────────
//  GESTIONNAIRE DE DÉCONNEXION
// ─────────────────────────────────────────────────
function handleDisconnect(ws) {
  const info = wsRegistry.get(ws);
  wsRegistry.delete(ws);
  if (!info) return;

  if (info.type === 'client') {
    const { id } = info;
    connectedClients.delete(id);
    if (db.clients[id]) {
      db.clients[id].status    = 'offline';
      db.clients[id].last_seen = new Date().toISOString();
      dbSave();
    }
    dbAddHistory(id, 'disconnect');
    notifyAdmins({ type: 'client_disconnected', clientId: id });
    console.log(`[WS] Client déconnecté: ${id}`);
  } else if (info.type === 'owner') {
    ownerSessions.delete(info.id);
    console.log(`[WS] Owner déconnecté: ${info.id} (client: ${info.clientId})`);
  } else if (info.type === 'admin') {
    adminSessions.delete(info.id);
    console.log(`[WS] Admin déconnecté: ${info.id}`);
  }
}

// ─────────────────────────────────────────────────
//  HELPERS
// ─────────────────────────────────────────────────
function send(ws, data) {
  try {
    if (ws && ws.readyState === WebSocket.OPEN)
      ws.send(JSON.stringify(data));
  } catch(e) { /* ignore */ }
}

function notifyAdmins(data) {
  adminSessions.forEach(ws => send(ws, data));
}

function broadcastAdmins(data) {
  adminSessions.forEach(ws => send(ws, data));
}

function buildClientInfo(id) {
  const c = db.clients[id];
  if (!c) return null;
  return { ...c, isOnline: connectedClients.has(id) };
}

function buildClientList() {
  return Object.values(db.clients)
    .map(c => ({ ...c, isOnline: connectedClients.has(c.client_id) }))
    .sort((a, b) => new Date(b.last_seen) - new Date(a.last_seen));
}

// ─────────────────────────────────────────────────
//  NETTOYAGE AUTOMATIQUE — marquer offline
// ─────────────────────────────────────────────────
setInterval(() => {
  const limit = new Date(Date.now() - OFFLINE_TIMEOUT).toISOString();
  let changed = 0;
  Object.values(db.clients).forEach(c => {
    if (c.status === 'online' && c.last_seen < limit && !connectedClients.has(c.client_id)) {
      c.status = 'offline';
      changed++;
    }
  });
  if (changed > 0) { dbSave(); console.log(`[Cleanup] ${changed} client(s) marqué(s) offline`); }
}, 30000);

// ─────────────────────────────────────────────────
//  API REST
// ─────────────────────────────────────────────────

// POST /api/register  ─ Créer un compte permanent
app.post('/api/register', (req, res) => {
  const { name, email, phone, custom_id } = req.body || {};

  if (!name || typeof name !== 'string' || !name.trim()) {
    return res.status(400).json({ success: false, error: 'Le nom est requis' });
  }

  const clientId = custom_id?.trim() || genId('SV');

  if (db.clients[clientId]) {
    return res.status(409).json({
      success: false,
      error: 'Cet ID existe déjà',
      existing: { client_id: clientId, name: db.clients[clientId].name },
    });
  }

  const now = new Date().toISOString();
  const registrationId = genId('REG');

  db.clients[clientId] = {
    client_id:       clientId,
    registration_id: registrationId,
    name:            name.trim(),
    email:           (email || '').trim(),
    phone:           (phone || '').trim(),
    status:          'offline',
    created_at:      now,
    last_seen:       now,
    last_ip:         '',
  };
  dbSave();
  dbAddHistory(clientId, 'register');
  notifyAdmins({ type: 'new_registration', client: buildClientInfo(clientId) });

  console.log(`[API] Compte créé: ${clientId} (${name.trim()})`);

  return res.status(201).json({
    success: true,
    data: {
      client_id:       clientId,
      registration_id: registrationId,
      name:            db.clients[clientId].name,
      email:           db.clients[clientId].email,
      created_at:      now,
    },
  });
});

// GET /api/clients/:id  ─ Récupérer un client
app.get('/api/clients/:id', (req, res) => {
  const c = db.clients[req.params.id];
  if (!c) return res.status(404).json({ success: false, error: 'Client introuvable' });
  return res.json({ success: true, data: buildClientInfo(req.params.id) });
});

// GET /api/clients  ─ Tous les clients
app.get('/api/clients', (req, res) => {
  return res.json({ success: true, data: buildClientList() });
});

// DELETE /api/clients/:id  ─ Supprimer un compte
app.delete('/api/clients/:id', (req, res) => {
  const id = req.params.id;
  if (!db.clients[id]) return res.status(404).json({ success: false, error: 'Client introuvable' });
  const { name } = db.clients[id];
  delete db.clients[id];
  dbSave();
  const ws = connectedClients.get(id);
  if (ws) { connectedClients.delete(id); wsRegistry.delete(ws); try { ws.close(); } catch(e){} }
  notifyAdmins({ type: 'client_deleted', clientId: id });
  console.log(`[API] Compte supprimé: ${id} (${name})`);
  return res.json({ success: true, message: `Compte "${name}" supprimé` });
});

// POST /api/heartbeat  ─ Heartbeat HTTP
app.post('/api/heartbeat', (req, res) => {
  const { clientId } = req.body || {};
  if (!db.clients[clientId]) return res.status(404).json({ success: false, error: 'Client introuvable' });
  db.clients[clientId].status    = 'online';
  db.clients[clientId].last_seen = new Date().toISOString();
  dbSave();
  return res.json({ success: true, status: 'online' });
});

// GET /api/clients/:id/history
app.get('/api/clients/:id/history', (req, res) => {
  const events = db.history
    .filter(e => e.client_id === req.params.id)
    .sort((a, b) => new Date(b.timestamp) - new Date(a.timestamp))
    .slice(0, 200);
  return res.json({ success: true, data: events });
});

// GET /api/stats
app.get('/api/stats', (req, res) => {
  const all = Object.values(db.clients);
  return res.json({
    success: true,
    data: {
      totalClients:    all.length,
      onlineClients:   all.filter(c => connectedClients.has(c.client_id)).length,
      adminSessions:   adminSessions.size,
      totalHistory:    db.history.length,
      totalConnections: db.history.filter(e => e.event_type === 'connect').length,
    },
  });
});

// POST /api/clients/:id/call  ─ Appel HTTP (utile pour APK sans WS)
app.post('/api/clients/:id/call', (req, res) => {
  const id  = req.params.id;
  const { mode } = req.body || {};
  if (!db.clients[id]) return res.status(404).json({ success: false, error: 'Client introuvable' });
  const cws = connectedClients.get(id);
  if (!cws || cws.readyState !== WebSocket.OPEN)
    return res.status(503).json({ success: false, error: 'Client hors ligne' });

  const adminSID = adminSessions.keys().next().value || 'ADMIN_BROADCAST';
  send(cws, { type: 'incoming_call', mode: mode || 'manual', adminSID });
  notifyAdmins({ type: 'call_initiated', clientId: id });
  return res.json({ success: true, message: `Appel envoyé à ${db.clients[id].name}` });
});

// ─────────────────────────────────────────────────
//  DÉMARRAGE
// ─────────────────────────────────────────────────
server.listen(PORT, '0.0.0.0', () => {
  console.log('\n╔══════════════════════════════════════╗');
  console.log('║     SECUREVIEW SERVER  v2.0          ║');
  console.log(`║  Port    : ${PORT}                     ║`);
  console.log(`║  BDD     : secureview_db.json        ║`);
  console.log(`║  Comptes : ${String(Object.keys(db.clients).length).padEnd(4)}                     ║`);
  console.log('╚══════════════════════════════════════╝\n');
});

function gracefulShutdown(signal) {
  console.log(`\n[Server] ${signal} reçu — arrêt propre...`);
  if (dbSaveTimer) { clearTimeout(dbSaveTimer); dbSaveTimer = null; }
  try { fs.writeFileSync(DB_FILE, JSON.stringify(db, null, 2), 'utf8'); }
  catch(e) { console.error('[DB] Erreur sauvegarde finale:', e.message); }
  server.close(() => process.exit(0));
  setTimeout(() => process.exit(1), 5000);
}

process.on('SIGINT',  () => gracefulShutdown('SIGINT'));
process.on('SIGTERM', () => gracefulShutdown('SIGTERM'));
process.on('uncaughtException',  (e) => console.error('[UNCAUGHT]', e));
process.on('unhandledRejection', (e) => console.error('[UNHANDLED]', e));