const baileys = require('@whiskeysockets/baileys');
const makeWASocket = baileys.default || baileys.makeWASocket || baileys;
const { useMultiFileAuthState, DisconnectReason, fetchLatestBaileysVersion } = baileys;
const pino = require('pino');
const axios = require('axios');
const fs = require('fs');
const path = require('path');

const sessions = new Map(); // Store active sockets in memory
const retryCounters = new Map(); // Track reconnection attempts per session

const MAX_RETRIES = 5; // Maximum reconnection attempts before giving up

// Local folder for saving auth keys
const SESSIONS_DIR = path.join(__dirname, 'sessions');
if (!fs.existsSync(SESSIONS_DIR)) {
    fs.mkdirSync(SESSIONS_DIR, { recursive: true });
}

async function sendWebhook(webhook_url, payload) {
    try {
        console.log(`[Webhook] Sending to ${webhook_url} | state=${payload.state}`);
        const response = await axios.post(webhook_url, payload, {
            headers: {
                'Content-Type': 'application/json',
                'X-Webhook-Secret': process.env.WEBHOOK_SECRET || ''
            },
            timeout: 10000
        });
        console.log(`[Webhook] ✅ Success | HTTP ${response.status}`);
    } catch (err) {
        if (err.response) {
            console.error(`[Webhook] ❌ HTTP ${err.response.status} | ${JSON.stringify(err.response.data)}`);
        } else {
            console.error(`[Webhook] ❌ Network Error: ${err.message}`);
        }
    }
}

async function startSession(session_key, webhook_url) {
    // Return existing socket if it's already active
    if (sessions.has(session_key)) {
        console.log(`[Session] ${session_key} already active, reusing`);
        return sessions.get(session_key);
    }

    console.log(`[Session] Starting ${session_key} → webhook: ${webhook_url}`);

    const sessionFolder = path.join(SESSIONS_DIR, session_key);
    const { state, saveCreds } = await useMultiFileAuthState(sessionFolder);

    // Fetch the latest WhatsApp Web version to avoid 405 rejection
    let version;
    try {
        const versionInfo = await fetchLatestBaileysVersion();
        version = versionInfo.version;
        console.log(`[Baileys] Using WA version: ${version}`);
    } catch (e) {
        console.warn(`[Baileys] Could not fetch version, using default`);
    }

    const socketConfig = {
        auth: state,
        printQRInTerminal: false,
        logger: pino({ level: 'silent' }),
        browser: ['Nabeh Gateway', 'Chrome', '120.0.0']
    };
    if (version) socketConfig.version = version;

    const sock = makeWASocket(socketConfig);
    console.log(`[Session] Socket created for ${session_key}`);

    sessions.set(session_key, sock);

    sock.ev.on('creds.update', saveCreds);

    sock.ev.on('connection.update', async (update) => {
        const { connection, lastDisconnect, qr } = update;

        if (qr) {
            console.log(`[QR] Generated for ${session_key}`);
            // Reset retry counter on QR generation (session is alive)
            retryCounters.set(session_key, 0);
            await sendWebhook(webhook_url, {
                session_key,
                state: 'waiting_qr',
                qr_code: qr
            });
        }

        if (connection === 'close') {
            const statusCode = lastDisconnect?.error?.output?.statusCode;
            const shouldReconnect = statusCode !== DisconnectReason.loggedOut;
            const retries = (retryCounters.get(session_key) || 0) + 1;
            retryCounters.set(session_key, retries);

            console.log(`[Connection] ${session_key} closed | code=${statusCode} | retry=${retries}/${MAX_RETRIES} | shouldReconnect=${shouldReconnect}`);

            if (shouldReconnect && retries <= MAX_RETRIES) {
                // Try reconnecting with exponential backoff
                sessions.delete(session_key);
                const delay = Math.min(retries * 3000, 15000); // 3s, 6s, 9s, 12s, 15s
                console.log(`[Connection] Reconnecting ${session_key} in ${delay}ms...`);
                setTimeout(() => startSession(session_key, webhook_url), delay);
            } else {
                // Either logged out, banned, or max retries exceeded
                console.log(`[Connection] ${session_key} permanently closed. Cleaning up.`);
                await cleanupSession(session_key);
                await sendWebhook(webhook_url, {
                    session_key,
                    state: 'disconnected'
                });
            }
        } else if (connection === 'open') {
            console.log(`[Connection] ✅ ${session_key} connected successfully!`);
            retryCounters.set(session_key, 0); // Reset on successful connection

            // Parse phone number from the JID (e.g. 9665XXXXXXX@s.whatsapp.net)
            const phone = sock.user.id.split(':')[0];

            await sendWebhook(webhook_url, {
                session_key,
                state: 'connected',
                phone: phone
            });
        }
    });

    return sock;
}

/**
 * Cleanup session: remove from memory and delete auth files
 */
async function cleanupSession(session_key) {
    const sock = sessions.get(session_key);
    if (sock) {
        try { sock.end(); } catch (e) { } // Gracefully close socket without logout
        sessions.delete(session_key);
    }
    retryCounters.delete(session_key);

    // Wipe the auth directory so a fresh session can be created next time
    const sessionFolder = path.join(SESSIONS_DIR, session_key);
    if (fs.existsSync(sessionFolder)) {
        fs.rmSync(sessionFolder, { recursive: true, force: true });
        console.log(`[Cleanup] Deleted session folder for ${session_key}`);
    }
}

/**
 * Disconnect session: logout from WhatsApp and cleanup
 */
async function disconnectSession(session_key) {
    const sock = sessions.get(session_key);
    if (sock) {
        try { sock.logout(); } catch (e) { } // best effort logout
        sessions.delete(session_key);
    }
    retryCounters.delete(session_key);

    // Completely wipe the auth directory
    const sessionFolder = path.join(SESSIONS_DIR, session_key);
    if (fs.existsSync(sessionFolder)) {
        fs.rmSync(sessionFolder, { recursive: true, force: true });
        console.log(`[Disconnect] Deleted session folder for ${session_key}`);
    }
}

module.exports = {
    startSession,
    disconnectSession
};