require("dotenv").config();
const express = require("express");
const mongoose = require("mongoose");
const cors = require("cors");
const http = require("http");
const socketio = require("socket.io");
const helmet = require("helmet");
const rateLimit = require("express-rate-limit");
const { errorHandler } = require("./middleware/errorHandler");
const socketAuth = require("./middleware/socketAuth");

const app = express();
const server = http.createServer(app);
const io = socketio(server, {
  cors: {
    origin: process.env.FRONTEND_URL || "http://localhost:3000",
    methods: ["GET", "POST"],
    credentials: true,
  },
});
const port = process.env.PORT || 5000;

// Security Headers - Helmet
app.use(helmet());

// CORS Configuration
app.use(
  cors({
    origin: process.env.FRONTEND_URL || "http://localhost:3000",
    credentials: true,
  }),
);

// Body Parser
app.use(express.json());

// Rate Limiting for Auth Routes (5 requests per 15 minutes)
const authLimiter = rateLimit({
  windowMs: 15 * 60 * 1000, // 15 minutes
  max: 5, // 5 requests per windowMs
  message: {
    success: false,
    error: "Too many authentication attempts, please try again later",
  },
  standardHeaders: true,
  legacyHeaders: false,
});

// General API Rate Limiting (100 requests per 15 minutes)
const apiLimiter = rateLimit({
  windowMs: 15 * 60 * 1000, // 15 minutes
  max: 100, // 100 requests per windowMs
  message: {
    success: false,
    error: "Too many requests, please try again later",
  },
  standardHeaders: true,
  legacyHeaders: false,
});

// MongoDB Connection
mongoose
  .connect(process.env.MONGO_URI, {
    useNewUrlParser: true,
    useUnifiedTopology: true,
  })
  .then(() => console.log("MongoDB connected"))
  .catch((err) => console.log("MongoDB connection error:", err));

// Socket.IO Authentication Middleware
io.use(socketAuth);

// Socket.IO Setup with Authentication
io.on("connection", (socket) => {
  console.log(`Client connected: ${socket.user.id}`);

  socket.on("joinEvent", (eventId) => {
    socket.join(`event_${eventId}`);
    console.log(`User ${socket.user.id} joined event ${eventId}`);
  });

  socket.on("joinPost", (postId) => {
    socket.join(`post_${postId}`);
    console.log(`User ${socket.user.id} joined post ${postId}`);
  });

  socket.on("eventUpdate", (data) => {
    io.to(`event_${data.eventId}`).emit("update", data.message);
  });

  socket.on("disconnect", () => {
    console.log(`Client disconnected: ${socket.user.id}`);
  });
});

// Make io available to routes
app.set("io", io);

// Routes
const authRoutes = require("./routes/auth");
const streetRoutes = require("./routes/streets");
const taskRoutes = require("./routes/tasks");
const postRoutes = require("./routes/posts");
const commentsRoutes = require("./routes/comments");
const eventRoutes = require("./routes/events");
const rewardRoutes = require("./routes/rewards");
const reportRoutes = require("./routes/reports");
const badgesRoutes = require("./routes/badges");
const aiRoutes = require("./routes/ai");
const paymentRoutes = require("./routes/payments");
const userRoutes = require("./routes/users");

// Apply rate limiters
app.use("/api/auth/register", authLimiter);
app.use("/api/auth/login", authLimiter);
app.use("/api", apiLimiter);

// Routes
app.use("/api/auth", authRoutes);
app.use("/api/streets", streetRoutes);
app.use("/api/tasks", taskRoutes);
app.use("/api/posts", postRoutes);
app.use("/api/posts", commentsRoutes); // Comments are nested under posts
app.use("/api/events", eventRoutes);
app.use("/api/rewards", rewardRoutes);
app.use("/api/reports", reportRoutes);
app.use("/api/badges", badgesRoutes);
app.use("/api/ai", aiRoutes);
app.use("/api/payments", paymentRoutes);
app.use("/api/users", userRoutes);

app.get("/", (req, res) => {
  res.send("Street Adoption App Backend");
});

// Error Handler Middleware (must be last)
app.use(errorHandler);

server.listen(port, () => {
  console.log(`Server running on port ${port}`);
});