"use strict";

const { WebSocketServer } = require("ws");
const fs = require("fs");
const path = require("path");

// ── Konfiguration aus Umgebungsvariablen ────────────────────────────
const PORT = parseInt(process.env.PORT || "3000", 10);
const MAX_SESSIONS = parseInt(process.env.MAX_SESSIONS || "10", 10);
const UPDATES_DIR = process.env.UPDATES_DIR || "/updates";
// Kein Polling — APK wird manuell per git pull bereitgestellt

// Erlaubte Nachrichtentypen — alles andere wird verworfen
const ALLOWED_TYPES = new Set([
  "chat", "audio", "file", "location", "mode", "log", "event", "heartbeat",
  "file_request", "file_response", "file_saved", "stt_result", "config", "tts_request",
  "xtts_request", "xtts_response", "xtts_list_voices", "xtts_voices_list", "voice_upload", "xtts_voice_saved",
  "update_check", "update_available", "update_download", "update_data",
]);

// Token-Raum: token -> { clients: Set<ws> }
const rooms = new Map();

// ── Hilfsfunktionen ─────────────────────────────────────────────────

function timestamp() {
  return new Date().toISOString();
}

function log(msg) {
  console.log(`[${timestamp()}] ${msg}`);
}

// Leere Räume und tote Clients aufräumen
function cleanupRooms() {
  for (const [token, room] of rooms) {
    // Tote Clients entfernen
    for (const client of room.clients) {
      if (client.readyState > 1) room.clients.delete(client);
    }
    // Raum löschen wenn leer
    if (room.clients.size === 0) {
      rooms.delete(token);
      log(`Leerer Raum entfernt: ${token.slice(0, 8)}...`);
    }
  }
}

// ── WebSocket-Server starten ────────────────────────────────────────

const wss = new WebSocketServer({ port: PORT });

wss.on("listening", () => {
  log(`RVS läuft auf Port ${PORT} | Max Sessions: ${MAX_SESSIONS}`);
  // Beim Start pruefen ob eine APK da ist
  const apkInfo = getLatestAPK();
  if (apkInfo) log(`APK bereit: v${apkInfo.version} (${(fs.statSync(apkInfo.path).size / 1024 / 1024).toFixed(1)}MB)`);
});

wss.on("connection", (ws, req) => {
  // Token aus URL-Query lesen: ws://host:port/?token=abc123
  const url = new URL(req.url, `http://${req.headers.host}`);
  let token = url.searchParams.get("token");

  // Wenn kein Token in der URL, auf erste Nachricht warten
  if (!token) {
    ws.once("message", (raw) => {
      try {
        const msg = JSON.parse(raw);
        if (msg.token) {
          registerClient(ws, msg.token);
        } else {
          ws.close(4000, "Kein Token angegeben");
        }
      } catch {
        ws.close(4000, "Ungültige erste Nachricht — Token erwartet");
      }
    });
    return;
  }

  registerClient(ws, token);
});

function registerClient(ws, token) {
  // Maximale Anzahl aktiver Sessions prüfen
  if (!rooms.has(token) && rooms.size >= MAX_SESSIONS) {
    ws.close(4002, "Maximale Anzahl aktiver Sessions erreicht");
    log(`Abgelehnt: Session-Limit (${MAX_SESSIONS}) erreicht`);
    return;
  }

  // Raum erstellen oder betreten
  if (!rooms.has(token)) {
    rooms.set(token, { clients: new Set() });
    log(`Neuer Raum: ${token.slice(0, 8)}...`);
  }

  const room = rooms.get(token);
  room.clients.add(ws);
  ws._token = token;

  log(`Client verbunden: ${token.slice(0, 8)}... (${room.clients.size} im Raum)`);

  // Nachrichten an alle anderen Clients im selben Raum weiterleiten
  ws.on("message", (raw) => {
    let msg;
    try {
      msg = JSON.parse(raw);
    } catch {
      return; // Keine gültige JSON-Nachricht — ignorieren
    }

    // Nur erlaubte Nachrichtentypen durchlassen
    if (!msg.type || !ALLOWED_TYPES.has(msg.type)) {
      return;
    }

    // Update-Check: direkt an den anfragenden Client antworten (nicht relay'en)
    if (msg.type === "update_check") {
      const clientVersion = msg.payload?.version || "0.0.0.0";
      const apkInfo = getLatestAPK();
      if (apkInfo && compareVersions(apkInfo.version, clientVersion) > 0) {
        ws.send(JSON.stringify({
          type: "update_available",
          payload: {
            version: apkInfo.version,
            downloadUrl: `/update/latest.apk`,
            size: fs.statSync(apkInfo.path).size,
          },
          timestamp: Date.now(),
        }));
      }
      return;
    }

    // Update-Download: APK als Base64 ueber WebSocket senden
    if (msg.type === "update_download") {
      const apkInfo = getLatestAPK();
      if (!apkInfo) {
        ws.send(JSON.stringify({ type: "update_data", payload: { error: "Keine APK verfuegbar" }, timestamp: Date.now() }));
        return;
      }
      try {
        const data = fs.readFileSync(apkInfo.path);
        const base64 = data.toString("base64");
        const sizeMB = (data.length / 1024 / 1024).toFixed(1);
        log(`APK sende: v${apkInfo.version} (${sizeMB}MB) an Client`);
        ws.send(JSON.stringify({
          type: "update_data",
          payload: {
            version: apkInfo.version,
            base64,
            size: data.length,
            fileName: `ARIA-v${apkInfo.version}.apk`,
          },
          timestamp: Date.now(),
        }));
      } catch (err) {
        ws.send(JSON.stringify({ type: "update_data", payload: { error: err.message }, timestamp: Date.now() }));
      }
      return;
    }

    // An alle anderen Clients im Raum weiterleiten
    for (const client of room.clients) {
      if (client !== ws && client.readyState === 1) {
        client.send(raw.toString());
      }
    }
  });

  ws.on("close", () => {
    room.clients.delete(ws);
    log(`Client getrennt: ${token.slice(0, 8)}... (${room.clients.size} verbleibend)`);
    if (room.clients.size === 0) {
      rooms.delete(token);
      log(`Raum geschlossen: ${token.slice(0, 8)}...`);
    }
  });

  ws.on("error", (err) => {
    log(`Fehler: ${err.message}`);
    room.clients.delete(ws);
  });
}

// ── Heartbeat — hält Verbindungen am Leben, räumt tote auf ──────────

const HEARTBEAT_INTERVAL = 15_000;

const heartbeat = setInterval(() => {
  for (const client of wss.clients) {
    if (client.isAlive === false) {
      log(`Toter Client entfernt (kein Pong)`);
      client.terminate();
      continue;
    }
    client.isAlive = false;
    client.ping();
  }
}, HEARTBEAT_INTERVAL);

wss.on("connection", (ws) => {
  ws.isAlive = true;
  ws.on("pong", () => { ws.isAlive = true; });
  // App-seitiger Heartbeat (JSON) zaehlt auch als lebendig
  const origOnMessage = ws._events?.message;
  ws.on("message", (raw) => {
    try {
      const msg = JSON.parse(raw);
      if (msg.type === "heartbeat") ws.isAlive = true;
    } catch {}
  });
});

// Aufräumen alle 30 Sekunden (statt 60)
const cleanup = setInterval(cleanupRooms, 30_000);

wss.on("close", () => {
  clearInterval(heartbeat);
  clearInterval(cleanup);
});

// ── Auto-Update: APK-Erkennung + Push ──────────────────────────────

let latestVersion = null;

function getLatestAPK() {
  try {
    if (!fs.existsSync(UPDATES_DIR)) return null;
    const files = fs.readdirSync(UPDATES_DIR)
      .filter(f => f.endsWith(".apk"))
      .map(f => {
        // ARIA-v0.0.2.3.apk oder ARIA-Cockpit-release.apk
        const match = f.match(/(\d+\.\d+\.\d+[\.\d]*)/);
        return { file: f, path: path.join(UPDATES_DIR, f), version: match ? match[1] : null };
      })
      .filter(f => f.version)
      .sort((a, b) => compareVersions(b.version, a.version)); // Neueste zuerst

    return files[0] || null;
  } catch {
    return null;
  }
}

function compareVersions(a, b) {
  const pa = a.split(".").map(Number);
  const pb = b.split(".").map(Number);
  for (let i = 0; i < Math.max(pa.length, pb.length); i++) {
    const diff = (pa[i] || 0) - (pb[i] || 0);
    if (diff !== 0) return diff;
  }
  return 0;
}

function notifyClientsAboutUpdate(apkInfo) {
  const msg = JSON.stringify({
    type: "update_available",
    payload: {
      version: apkInfo.version,
      downloadUrl: `/update/latest.apk`,
      size: fs.statSync(apkInfo.path).size,
    },
    timestamp: Date.now(),
  });

  // An alle Clients in allen Rooms senden
  for (const [, room] of rooms) {
    for (const client of room.clients) {
      if (client.readyState === 1) {
        client.send(msg);
      }
    }
  }
  log(`Update-Benachrichtigung gesendet: v${apkInfo.version} (${rooms.size} Raum/Raeume)`);
}

// Kein Polling — Update-Check passiert on-demand (update_check Message von App)

// ── Sauberes Herunterfahren ─────────────────────────────────────────

process.on("SIGTERM", () => {
  log("SIGTERM empfangen — fahre herunter");
  wss.close(() => process.exit(0));
});

process.on("SIGINT", () => {
  log("SIGINT empfangen — fahre herunter");
  wss.close(() => process.exit(0));
});