const express = require('express');
const crypto = require('node:crypto');
const dotenv = require('dotenv');
dotenv.config();

const app = express();

const PORT = process.env.PORT || 3000;
const WEBHOOK_SECRET = process.env.TICKETWAVE_WEBHOOK_SECRET;

if (!WEBHOOK_SECRET) {
    console.error('Missing TICKETWAVE_WEBHOOK_SECRET');
    process.exit(1);
}

// Signature RAW body पर बनती है, इसलिए untouched bytes को वैसे ही रखें।
app.use('/webhooks/ticketwave', express.raw({ type: 'application/json' }));

// इससे पुरानी किसी भी request को reject करें, ताकि captured request बाद में replay न की जा सके।
const MAX_TIMESTAMP_AGE = 5 * 60; // 5 minutes

function verifySignature(req) {
    const Signature = req.get('X-TicketWave-Signature');
    const Timestamp = req.get('X-TicketWave-Timestamp');

    if (!Signature || !Timestamp) return false;

    // 1. Timestamp हाल का होना चाहिए
    const Age = Math.abs(Math.floor(Date.now() / 1000) - Number(Timestamp));
    if (!Number.isFinite(Age) || Age > MAX_TIMESTAMP_AGE) return false;

    // 2. `${timestamp}.${rawBody}` पर HMAC दोबारा compute करें
    const Expected = crypto
        .createHmac('sha256', WEBHOOK_SECRET)
        .update(`${Timestamp}.${req.body}`)
        .digest('hex');

    // 3. Constant time में compare करें
    const Received = Signature.replace('sha256=', '');
    const ExpectedBuffer = Buffer.from(Expected, 'hex');
    const ReceivedBuffer = Buffer.from(Received, 'hex');

    if (ExpectedBuffer.length !== ReceivedBuffer.length) return false;
    return crypto.timingSafeEqual(ExpectedBuffer, ReceivedBuffer);
}

// संभाली गई delivery ids याद रखें, क्योंकि retry वही event फिर से भेजता है।
const HandledDeliveries = new Set();

app.post('/webhooks/ticketwave', (req, res) => {
    if (!verifySignature(req)) {
        console.warn('Rejected a request with an invalid signature');
        return res.status(401).json({ error: 'invalid signature' });
    }

    const DeliveryId = req.get('X-TicketWave-Delivery');
    const Payload = JSON.parse(req.body);

    // तुरंत जवाब दें - आपके पास 10 seconds हैं, और धीमे replies retry हो जाते हैं।
    res.status(200).json({ received: true });

    // उस delivery को ignore करें जिसे हम पहले ही संभाल चुके हैं
    if (HandledDeliveries.has(DeliveryId)) return;
    HandledDeliveries.add(DeliveryId);

    handleEvent(Payload).catch((err) => {
        console.error(`Failed to handle ${Payload.event}:`, err);
    });
});

async function handleEvent(payload) {
    const { event, guild_id: guildId, data } = payload;

    // Dashboard का test button यही भेजता है
    if (data.test) {
        console.log(`Test event (${event}) received from guild ${guildId}`);
        return;
    }

    switch (event) {
        case 'ticket.created':
            console.log(`[${guildId}] ${data.ticket_id} opened by ${data.user?.username}`);
            break;

        case 'ticket.closed':
            console.log(`[${guildId}] ${data.ticket_id} closed by ${data.closed_by?.username} (${data.reason ?? 'no reason'})`);
            break;

        case 'ticket.updated':
            console.log(`[${guildId}] ${data.ticket_id} updated: ${data.action}`, data.changes);
            break;

        case 'message.sent':
            console.log(`[${guildId}] ${data.ticket_id} ${data.is_staff ? 'staff' : 'member'} ${data.author?.username}: ${data.content}`);
            break;

        case 'blacklist.added':
            console.log(`[${guildId}] ${data.user?.username} blacklisted (${data.reason ?? 'no reason'})`);
            break;

        case 'blacklist.removed':
            console.log(`[${guildId}] ${data.user?.username} removed from the blacklist`);
            break;

        default:
            // नए event types समय के साथ जोड़े जाते हैं - जो आप नहीं जानते, उस पर कभी throw न करें।
            console.log(`[${guildId}] Unhandled event ${event}`);
    }
}

app.listen(PORT, () => {
    console.log(`Listening for TicketWave webhooks on port ${PORT}`);
});

// किसी भी SQL database के साथ example
async function alreadyHandled(deliveryId) {
    const [rows] = await db.query(
        'SELECT 1 FROM webhook_deliveries WHERE delivery_id = ?',
        [deliveryId]
    );
    if (rows.length > 0) return true;

    await db.query(
        'INSERT INTO webhook_deliveries (delivery_id) VALUES (?)',
        [deliveryId]
    );
    return false;
}

# ngrok
ngrok http 3000

# or Cloudflare Tunnel
cloudflared tunnel --url http://localhost:3000