const express = require('express');
const admin = require('firebase-admin');
const crypto = require('crypto');
const cluster = require('cluster');
const os = require('os');

const numCPUs = os.cpus().length;

if (cluster.isMaster) {
    console.log(`[Master Process ${process.pid}] Server Active. Detecting ${numCPUs} CPU cores...`);
    for (let i = 0; i < numCPUs; i++) { cluster.fork(); }
    cluster.on('exit', (worker) => { cluster.fork(); });
} else {
    const app = express();
    app.use(express.json());
    const workerId = process.pid;

    // ==========================================
    // ১. ডাইনামিক CORS (ডোমেন লক) মিডলওয়্যার
    // ==========================================
    const allowedDomains = [
        'earnglow.raybil.tech',
        'earnglow-es.raybil.tech',
        'earnglow-rk.raybil.tech',
        'ffyef.raybil.tech'
    ];

    app.use((req, res, next) => {
        // হেলথ চেক রাউটগুলোর জন্য ডোমেন লক সম্পূর্ণ ওপেন (CORS Bypass)
        const publicPaths = ['/health', '/ch', '/unps'];
        if (publicPaths.includes(req.path)) {
            res.setHeader('Access-Control-Allow-Origin', '*');
            res.setHeader('Access-Control-Allow-Methods', 'GET, POST, OPTIONS');
            res.setHeader('Access-Control-Allow-Headers', 'Content-Type');
            return next();
        }

        // মেইন রিকোয়েস্টগুলোর জন্য কঠোর ডোমেন ভ্যালিডেশন
        const origin = req.headers.origin;
        let originDomain = '';
        
        if (origin) {
            try {
                originDomain = new URL(origin).hostname;
            } catch (e) {
                originDomain = '';
            }
        }

        if (allowedDomains.includes(originDomain)) {
            res.setHeader('Access-Control-Allow-Origin', origin);
            res.setHeader('Access-Control-Allow-Methods', 'POST, OPTIONS');
            res.setHeader('Access-Control-Allow-Headers', 'Content-Type, Authorization');
            
            // প্রি-ফ্লাইট (OPTIONS) রিকোয়েস্টের জন্য হ্যান্ডেল
            if (req.method === 'OPTIONS') {
                return res.sendStatus(200);
            }
            next();
        } else {
            // যদি কেউ অননুমোদিত ডোমেন বা পোস্টম্যান দিয়ে ডিরেক্ট হিট করার চেষ্টা করে
            console.log(`[Worker ${workerId}] Blocked Request from Unauthorized Origin: ${originDomain || 'No Origin'}`);
            return res.status(403).json({ error: 'CORS Policy: Access Denied for this Origin.' });
        }
    });

    // ==========================================
    // ২. ফায়ারবেজ মাল্টিপল অ্যাডমিন সেটআপ
    // ==========================================
    const initFirebase = (envAdmin, envUrl, appName) => {
        if (!process.env[envAdmin] || !process.env[envUrl]) return null;
        return admin.initializeApp({
            credential: admin.credential.cert(JSON.parse(process.env[envAdmin])),
            databaseURL: process.env[envUrl]
        }, appName);
    };

    const app1 = initFirebase('FIREBASE_ADMIN_1', 'FIREBASE_DB_URL_1', 'Admin1');
    const app3 = initFirebase('FIREBASE_ADMIN_3', 'FIREBASE_DB_URL_3', 'Admin3');
    const app4 = initFirebase('FIREBASE_ADMIN_4', 'FIREBASE_DB_URL_4', 'Admin4');

    const db1 = app1 ? app1.database() : null;
    const db3 = app3 ? app3.database() : null;
    const db4 = app4 ? app4.database() : null;

    // ==========================================
    // ৩. হেলথ চেক রাউটস (যেকোনো ডোমেন থেকে অ্যাক্সেসযোগ্য)
    // ==========================================
    const healthHandler = (req, res) => { res.send('Ok, yes, done'); };
    app.all('/health', healthHandler);
    app.all('/ch', healthHandler);
    app.all('/unps', healthHandler);

    // ==========================================
    // ৪. মিডলওয়্যার: শুধুমাত্র POST রিকোয়েস্ট পারমিট করা
    // ==========================================
    const checkPostMethod = (req, res, next) => {
        if (req.method !== 'POST') {
            return res.status(405).json({ error: 'Method Not Allowed. Only POST is accepted.' });
        }
        next();
    };

    // ==========================================
    // ৫. Telegram Security ভ্যালিডেশন মিডলওয়্যার
    // ==========================================
    const verifyTelegramAuth = (req, res, next) => {
        const { init_data, user_id, name } = req.body;
        if (!init_data) return res.status(401).json({ error: 'Unauthorized: init_data is missing' });

        try {
            const botToken = process.env.BOT_TOKEN;
            if (!botToken) return res.status(500).json({ error: 'Server configuration error' });

            const urlParams = new URLSearchParams(init_data);
            const hash = urlParams.get('hash');
            urlParams.delete('hash');

            const dataToCheck = [...urlParams.entries()].map(([key, value]) => `${key}=${value}`).sort().join('\n');
            const secretKey = crypto.createHmac('sha256', 'WebAppData').update(botToken).digest();
            const calculatedHash = crypto.createHmac('sha256', secretKey).update(dataToCheck).digest('hex');

            if (calculatedHash !== hash) return res.status(403).json({ error: 'Forbidden: Invalid Telegram signature' });

            const tgUser = JSON.parse(urlParams.get('user'));
            if (String(tgUser.id) !== String(user_id)) return res.status(403).json({ error: 'Forbidden: User ID mismatch' });

            const tgFullName = tgUser.last_name ? `${tgUser.first_name} ${tgUser.last_name}`.trim() : tgUser.first_name;
            if (String(tgFullName) !== String(name) && String(tgUser.first_name) !== String(name)) {
                return res.status(403).json({ error: 'Forbidden: Name mismatch' });
            }
            next();
        } catch (error) {
            return res.status(500).json({ error: 'Internal server error during validation' });
        }
    };

    // ==========================================
    // ৬. API: ক্রিয়েট অ্যাকাউন্ট (/creataccoumt)
    // ==========================================
    app.post('/creataccoumt', checkPostMethod, verifyTelegramAuth, async (req, res) => {
        const { user_id, refer_id, name, username, profile_pic_url } = req.body;
        try {
            const userRef = db1.ref('user').child(user_id);
            const snapshot = await userRef.once('value');

            if (snapshot.exists()) {
                const reply = { message: 'Account already exists. No action taken.' };
                console.log(`[Worker ${workerId}] User ID: ${user_id} | Status: Existing User | Reply: ${reply.message}`);
                return res.status(200).json(reply);
            }

            const newUserData = {
                user_id, refer_id: refer_id || null, name: name || null, username: username || null,
                profile_pic_url: profile_pic_url || null, balance: 0, total_withdraw: 0,
                total_withdraw_amount: 0, join_date: admin.database.ServerValue.TIMESTAMP, total_refer: 0
            };

            await userRef.set(newUserData);
            let logMsg = `[Worker ${workerId}] User ID: ${user_id} | DB1: Updated`;

            if (refer_id) {
                const referUserRef = db1.ref('user').child(refer_id);
                const referUserSnap = await referUserRef.once('value');

                if (referUserSnap.exists()) {
                    await referUserRef.child('total_refer').transaction((currentValue) => { return (currentValue || 0) + 1; });
                    const referListRef = db3.ref('refer').child(refer_id);
                    await referListRef.push(user_id);
                    logMsg += ` & DB3: Refer Updated`;
                }
            }

            const reply = { message: 'Account created successfully!' };
            console.log(`${logMsg} | Reply: ${reply.message}`);
            res.status(201).json(reply);
        } catch (error) {
            console.error(`[Worker ${workerId}] User ID: ${user_id || 'Unknown'} | Error in /creataccoumt`);
            res.status(500).json({ error: 'Internal Server Error' });
        }
    });

    // ==========================================
    // ৭. API: উইথড্র মেইন ব্যালেন্স (/withdraw-main)
    // ==========================================
    app.post('/withdraw-main', checkPostMethod, verifyTelegramAuth, async (req, res) => {
        const { user_id, method, address, time, amount } = req.body;
        const allowedMethods = ['bkash', 'mobile-gp', 'mobile-ar', 'mobile-ro', 'mobile-bl', 'mobile-tk', 'nagad', 'binance', 'usdt', 'ton'];

        if (!method || !address || !amount) return res.status(400).json({ error: 'Missing required fields' });
        if (!allowedMethods.includes(method)) return res.status(400).json({ error: 'Invalid withdrawal method' });

        try {
            const userRef = db1.ref('user').child(user_id);
            const snapshot = await userRef.once('value');
            if (!snapshot.exists()) return res.status(404).json({ error: 'User not found' });

            const userData = snapshot.val();
            const currentBalance = Number(userData.balance || 0);
            const requestAmount = Number(amount);

            if (currentBalance < requestAmount) return res.status(400).json({ error: 'Insufficient balance' });

            await userRef.child('balance').set(currentBalance - requestAmount);

            const pendingRef = db3.ref('withdrow/painding').child(user_id);
            await pendingRef.push({
                method, address, time: time || admin.database.ServerValue.TIMESTAMP, amount: requestAmount, status: 'pending'
            });

            const reply = { message: 'Withdrawal request successful' };
            console.log(`[Worker ${workerId}] User ID: ${user_id} | DB1: Balance Cut | DB3: Request Saved | Reply: ${reply.message}`);
            res.status(200).json(reply);
        } catch (error) {
            console.error(`[Worker ${workerId}] User ID: ${user_id} | Error in /withdraw-main`);
            res.status(500).json({ error: 'Internal Server Error' });
        }
    });

    // ==========================================
    // ৮. API: অ্যাড ব্যালেন্স উইথড্র (Admin 4 -> Admin 1)
    // ==========================================
    const adWithdrawPaths = [
        '/withdraw-link-visit', '/withdraw-adsgram-1', '/withdraw-adsgram-2',
        '/withdraw-gigapub-1', '/withdraw-gigapub-2', '/withdraw-monetag-1', '/withdraw-monetag-2'
    ];

    app.post(adWithdrawPaths, checkPostMethod, async (req, res) => {
        const { user_id, amount, method } = req.body;
        if (!user_id || !amount || method !== 'wallet') {
            return res.status(400).json({ error: 'Invalid request. Method must be wallet and amount is required.' });
        }

        const adNetworkName = req.path.replace('/withdraw-', '');
        const requestAmount = Number(amount);

        try {
            const adRef = db4.ref(adNetworkName).child(user_id);
            const adSnapshot = await adRef.once('value');
            if (!adSnapshot.exists()) return res.status(404).json({ error: 'No ad earnings found for this user' });

            let adCurrentBalance = Number(adSnapshot.val().balance || 0);
            if (adCurrentBalance < requestAmount) return res.status(400).json({ error: 'Insufficient ad balance' });

            await adRef.child('balance').set(adCurrentBalance - requestAmount);

            const mainUserRef = db1.ref('user').child(user_id);
            await mainUserRef.child('balance').transaction((currentMainBalance) => {
                return (currentMainBalance || 0) + requestAmount;
            });

            const reply = { message: `Success! ${requestAmount} transferred to main balance from ${adNetworkName}` };
            console.log(`[Worker ${workerId}] User ID: ${user_id} | DB4: Ad Balance Cut | DB1: Main Balance Added | Reply: ${reply.message}`);
            res.status(200).json(reply);
        } catch (error) {
            console.error(`[Worker ${workerId}] User ID: ${user_id} | Error in Ad Withdraw paths`);
            res.status(500).json({ error: 'Internal Server Error' });
        }
    });

    const PORT = process.env.PORT || 7860;
    app.listen(PORT);
}