const express = require('express');
const app = express();
const dotenv = require('dotenv');
const path = require('path');
const cors = require('cors');
const cookieParser = require('cookie-parser'); 
const connectDatabase = require('./config/connectDatabase');
const { execSync } = require('child_process');
const fs = require('fs');

dotenv.config({ path: path.join(__dirname, 'config', 'config.env') });

const products = require('./routes/product');
const users = require('./routes/user');
const adminRoutes = require('./routes/admin');

connectDatabase();

const isProduction = process.env.NODE_ENV === 'production';
const isDevelopment = process.env.NODE_ENV === 'development';
if (isProduction) {
  const buildPath = path.join(__dirname, '..', 'frontend', 'build');
  const frontendPath = path.join(__dirname, '..', 'frontend');
  
  if (!fs.existsSync(buildPath)) {
    console.log('🏗️  Building frontend for production...');
    try {
      const packageJsonPath = path.join(frontendPath, 'package.json');
      const nodeModulesPath = path.join(frontendPath, 'node_modules');
      
      if (!fs.existsSync(nodeModulesPath)) {
        console.log('📦 Installing frontend dependencies...');
        execSync('npm install', { 
          cwd: frontendPath, 
          stdio: 'inherit' 
        });
      }
      
      console.log('📦 Building React app...');
      execSync('npm run build', { 
        cwd: frontendPath, 
        stdio: 'inherit' 
      });
      console.log('✅ Frontend build completed');
    } catch (error) {
      console.error('❌ Frontend build failed:', error.message);
      console.log('⚠️  Starting server without frontend build...');
    }
  }
}

const getBackendUrl = () => {
  if (isProduction) {

    return process.env.APP_URL || `https://${process.env.HOST || 'localhost'}:${process.env.PORT || 7860}`;
  }
  return 'http://localhost:7860';
};

const getFrontendUrl = () => {
  if (isProduction) {

    return process.env.FRONTEND_URL || getBackendUrl().replace('7860', '3000').replace('api.', '');
  }
  return 'http://localhost:3000';
};

const corsOptions = {
  origin: function (origin, callback) {
    if (!origin) return callback(null, true);
    
    const backendUrl = getBackendUrl();
    const frontendUrl = getFrontendUrl();
    
    const allowedOrigins = [
      backendUrl,
      frontendUrl,
      'http://localhost:3000',
      'https://localhost:3000',
      'http://localhost:3001',
      'https://localhost:3001',
      'http://localhost:7860',
      'https://localhost:7860',
      'https://mkshopping.onrender.com',
      'https://mkshoppingbd.onrender.com',
      'https://kumar715-mkcart.hf.space'
    ]
    
    // Support Hugging Face Spaces dynamically
    if (origin.endsWith('.hf.space')) {
      return callback(null, true);
    }

    if (isDevelopment) {
      if (origin.includes('localhost') || origin.includes('127.0.0.1')) {
        return callback(null, true);
      }
    }
    
    if (allowedOrigins.includes(origin)) {
      callback(null, true);
    } else {
      console.log("Blocked by CORS:", origin);
      console.log("Allowed origins:", allowedOrigins);
      callback(new Error("Not allowed by CORS"));
    }
  },
  credentials: true,
  methods: ['GET', 'POST', 'PUT', 'DELETE', 'OPTIONS', 'PATCH'],
  allowedHeaders: [
    'Content-Type', 
    'Authorization', 
    'X-Requested-With',
    'Accept',
    'Origin',
    'Access-Control-Request-Method',
    'Access-Control-Request-Headers'
  ],
  exposedHeaders: ['Set-Cookie', 'Authorization'],
  preflightContinue: false,
  optionsSuccessStatus: 204
};

app.use(cors(corsOptions));

app.options('*', cors(corsOptions));

app.use(express.json());
app.use(express.urlencoded({ extended: true }));
app.use(cookieParser());

app.use('/uploads', express.static(path.join(__dirname, 'uploads')));

app.use('/images', express.static(path.join(__dirname, '../frontend/public/images')));

app.use('/api', products);
app.use('/api', users);
app.use('/api/admin', adminRoutes);

if (isProduction) {
  const buildPath = path.join(__dirname, '..', 'frontend', 'build');
  if (fs.existsSync(buildPath)) {
    app.use(express.static(buildPath));
    app.get('*', (req, res) => {
      res.sendFile(path.resolve(buildPath, 'index.html'));
    });
  }
}

app.use((err, req, res, next) => {
  const statusCode = res.statusCode === 200 ? 500 : res.statusCode;
  res.status(statusCode);
  res.json({
    message: err.message,
    stack: isDevelopment ? err.stack : {},
  });
});

app.listen(process.env.PORT, () => {
  console.log(`🚀 Server running on Port ${process.env.PORT} in ${process.env.NODE_ENV} mode`);
  console.log(`📡 Backend URL: ${getBackendUrl()}`);
  console.log(`🌐 Frontend URL: ${getFrontendUrl()}`);
  console.log(`🔧 Environment: ${isProduction ? 'Production' : 'Development'}`);
  
});