const express = require('express');
const http = require('http');
const socketIo = require('socket.io');
const mongoose = require('mongoose');
const cors = require('cors');
const bcrypt = require('bcryptjs');
const jwt = require('jsonwebtoken');
const path = require('path');
require('dotenv').config();

const app = express();
const server = http.createServer(app);

// Fix CORS configuration
const io = socketIo(server, {
  cors: {
    origin: "http://localhost:3000",
    methods: ["GET", "POST", "PUT", "DELETE"],
    credentials: false
  }
});

// CORS middleware - fix this part
app.use(cors({
  origin: "http://localhost:3000",
  credentials: false,
  methods: ["GET", "POST", "PUT", "DELETE"],
  allowedHeaders: ["Content-Type", "Authorization"]
}));

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

// Simple User Model (in-memory for now)
const users = [];

// Auth Routes
app.post('/api/auth/register', async (req, res) => {
  try {
    const { username, email, password, displayName } = req.body;

    console.log('Registration attempt:', { username, email, displayName });

    // Validation
    if (!username || !email || !password || !displayName) {
      return res.status(400).json({ error: 'All fields are required' });
    }

    // Check if user exists
    const existingUser = users.find(u => u.email === email || u.username === username);
    if (existingUser) {
      return res.status(400).json({ error: 'User already exists' });
    }

    // Hash password
    const hashedPassword = await bcrypt.hash(password, 12);

    // Create user
    const user = {
      id: Date.now().toString(),
      username,
      email,
      displayName,
      password: hashedPassword,
      avatar: null,
      status: 'online',
      lastSeen: new Date(),
      createdAt: new Date()
    };

    users.push(user);

    // Generate token
    const token = jwt.sign({ userId: user.id }, process.env.JWT_SECRET || 'fallback-secret', { expiresIn: '30d' });

    // Remove password from response
    const { password: _, ...userWithoutPassword } = user;

    console.log('User registered successfully:', userWithoutPassword.username);

    res.status(201).json({
      message: 'User registered successfully',
      user: userWithoutPassword,
      token
    });

  } catch (error) {
    console.error('Registration error:', error);
    res.status(500).json({ error: 'Server error during registration' });
  }
});

app.post('/api/auth/login', async (req, res) => {
  try {
    const { email, password } = req.body;

    console.log('Login attempt:', { email });

    if (!email || !password) {
      return res.status(400).json({ error: 'Email and password are required' });
    }

    // Find user
    const user = users.find(u => u.email === email);
    if (!user) {
      return res.status(401).json({ error: 'Invalid credentials' });
    }

    // Check password
    const isPasswordValid = await bcrypt.compare(password, user.password);
    if (!isPasswordValid) {
      return res.status(401).json({ error: 'Invalid credentials' });
    }

    // Update user status
    user.status = 'online';
    user.lastSeen = new Date();

    // Generate token
    const token = jwt.sign({ userId: user.id }, process.env.JWT_SECRET || 'fallback-secret', { expiresIn: '30d' });

    // Remove password from response
    const { password: _, ...userWithoutPassword } = user;

    console.log('User logged in:', userWithoutPassword.username);

    res.json({
      message: 'Login successful',
      user: userWithoutPassword,
      token
    });

  } catch (error) {
    console.error('Login error:', error);
    res.status(500).json({ error: 'Server error during login' });
  }
});

app.get('/api/auth/me', (req, res) => {
  const token = req.headers.authorization?.split(' ')[1];
  
  if (!token) {
    return res.status(401).json({ error: 'No token provided' });
  }

  try {
    const decoded = jwt.verify(token, process.env.JWT_SECRET || 'fallback-secret');
    const user = users.find(u => u.id === decoded.userId);
    
    if (!user) {
      return res.status(404).json({ error: 'User not found' });
    }

    const { password: _, ...userWithoutPassword } = user;
    res.json({ user: userWithoutPassword });

  } catch (error) {
    res.status(401).json({ error: 'Invalid token' });
  }
});

// Health check
app.get('/api/health', (req, res) => {
  res.json({ 
    status: 'OK', 
    message: 'YSNRFD Messenger Backend is running!',
    usersCount: users.length,
    timestamp: new Date().toISOString()
  });
});

// Test route to verify CORS is working
app.get('/api/test-cors', (req, res) => {
  res.json({ 
    message: 'CORS is working!',
    corsConfig: {
      origin: 'http://localhost:3000',
      credentials: false
    }
  });
});

// Socket.io connection
io.on('connection', (socket) => {
  console.log('User connected:', socket.id);
  
  socket.on('disconnect', () => {
    console.log('User disconnected:', socket.id);
  });
});

const PORT = process.env.PORT || 5000;
server.listen(PORT, () => {
  console.log(`🚀 YSNRFD Messenger backend running on port ${PORT}`);
  console.log(`🔧 Environment: ${process.env.NODE_ENV || 'development'}`);
  console.log(`🌍 Frontend URL: http://localhost:3000`);
  console.log(`🔍 Health check: http://localhost:${PORT}/api/health`);
  console.log(`🔍 CORS test: http://localhost:${PORT}/api/test-cors`);
  console.log(`👥 Registered users: ${users.length}`);
});