const express = require('express');
const { spawn } = require('child_process');
const { MongoClient } = require('mongodb');
const path = require('path');
const app = express();
const http = require('http').createServer(app);
const io = require('socket.io')(http, {
    cors: {
        origin: "*",
        methods: ["GET", "POST"]
    }
});
const crypto = require('crypto');
const fs = require('fs');

// MongoDB Connection
const MONGO_URI = process.env.MONGO_URI || "mongodb://localhost:27017";
let db;

async function connectDB() {
    try {
        const client = new MongoClient(MONGO_URI);
        await client.connect();
        db = client.db('whatsapp-bots');
        console.log("✅ Connected to MongoDB");
        
        // Initialize collections
        const collections = ['users', 'bots', 'sessions'];
        for (const colName of collections) {
            if (!(await db.listCollections({ name: colName }).hasNext())) {
                await db.createCollection(colName);
                console.log(`Created collection: ${colName}`);
            }
        }
        
        // Create admin user if not exists
        const adminExists = await db.collection('users').findOne({ username: 'admin' });
        if (!adminExists) {
            await db.collection('users').insertOne({
                username: 'admin',
                password: hashPassword('admin123'),
                isAdmin: true,
                createdAt: new Date()
            });
            console.log("👑 Created admin user (password: admin123)");
        }
    } catch (err) {
        console.error("❌ MongoDB connection error:", err);
        process.exit(1);
    }
}

function hashPassword(password) {
    return crypto
        .createHash('sha256')
        .update(password + (process.env.PEPPER || 'defaultPepper'))
        .digest('hex');
}

// Socket.IO
io.on('connection', (socket) => {
    console.log(`New connection: ${socket.id}`);
    
    // Force terminal initialization
    socket.emit('terminal-init', { 
        status: 'ready',
        timestamp: Date.now() 
    });
    
    // Terminal command handler
    socket.on('terminal-command', async (data) => {
        try {
            const { command, userId } = data;
            console.log(`Command from ${userId}: ${command}`);
            
            // Execute command in user's directory
            const userDir = `/persistent/storage/${userId}`;
            const child = spawn(command.split(' ')[0], command.split(' ').slice(1), {
                cwd: userDir
            });
            
            child.stdout.on('data', (data) => {
                socket.emit('terminal-output', data.toString());
            });
            
            child.stderr.on('data', (data) => {
                socket.emit('terminal-output', `ERROR: ${data.toString()}`);
            });
            
            child.on('close', (code) => {
                socket.emit('terminal-output', `Process exited with code ${code}\n`);
            });
        } catch (err) {
            socket.emit('terminal-output', `ERROR: ${err.message}\n`);
        }
    });
    
    // Authentication handlers
    socket.on('login', async (data) => {
        try {
            const { username, password } = data;
            const user = await db.collection('users').findOne({ 
                username,
                password: hashPassword(password)
            });
            
            if (user) {
                currentUser = user._id.toString();
                socket.emit('login-success', { 
                    userId: currentUser,
                    isAdmin: user.isAdmin 
                });
                
                // Ensure user directory exists
                const userDir = `/persistent/storage/${currentUser}`;
                if (!fs.existsSync(userDir)) {
                    fs.mkdirSync(userDir, { recursive: true });
                }
            } else {
                socket.emit('login-error', 'Invalid credentials');
            }
        } catch (err) {
            socket.emit('login-error', 'Authentication failed');
        }
    });
});

// Express middleware
app.use(express.static('public'));
app.use(express.json());

// Health check endpoint
app.get('/health', (req, res) => {
    res.status(200).json({ 
        status: 'healthy',
        timestamp: Date.now() 
    });
});

// Error handling
app.use((err, req, res, next) => {
    console.error('Global error:', err);
    io.emit('terminal-output', `SYSTEM ERROR: ${err.message}\n`);
    res.status(500).json({ error: err.message });
});

// Start server
const PORT = process.env.PORT || 7860;
connectDB().then(() => {
    http.listen(PORT, () => {
        console.log(`🚀 Server running on port ${PORT}`);
        
        // Restart any previously running bots
        db.collection('bots').find({ status: 'running' }).forEach(bot => {
            console.log(`Restarting bot for user ${bot.userId}`);
            startBotProcess(bot.userId, bot.repoUrl, bot.entryFile);
        });
    });
});

// Helper function to start bot processes
function startBotProcess(userId, repoUrl, entryFile) {
    const botDir = `/persistent/storage/${userId}`;
    
    // Clone repo if needed
    if (!fs.existsSync(botDir)) {
        const clone = spawn('git', ['clone', repoUrl, botDir]);
        clone.on('close', (code) => {
            if (code === 0) installDependencies(botDir, userId, repoUrl, entryFile);
        });
    } else {
        installDependencies(botDir, userId, repoUrl, entryFile);
    }
}

function installDependencies(botDir, userId, repoUrl, entryFile) {
    const install = spawn('npm', ['install'], { cwd: botDir });
    install.on('close', (code) => {
        if (code === 0) runBot(botDir, userId, repoUrl, entryFile);
    });
}

function runBot(botDir, userId, repoUrl, entryFile) {
    const botProcess = spawn('node', [entryFile], { cwd: botDir });
    
    // Save to database
    db.collection('bots').updateOne(
        { userId },
        { $set: { 
            status: 'running',
            repoUrl,
            entryFile,
            pid: botProcess.pid,
            lastStarted: new Date()
        }},
        { upsert: true }
    );
    
    // Handle process events
    botProcess.on('exit', (code) => {
        db.collection('bots').updateOne(
            { userId },
            { $set: { status: 'stopped', exitCode: code } }
        );
    });
}