server.js

const express = require('express');
const app = express();
const { MongoClient, ObjectId } = require('mongodb');
const path = require('path');
const bodyParser = require('body-parser');
const open = require('open');

// ---- 1. MongoDB connection string ----
const uri = "mongodb+srv://s3710021:Test1234@dba-cluster.jpcdrgc.mongodb.net/sample_airbnb?retryWrites=true&w=majority&appName=DBA-Cluster";
const client = new MongoClient(uri);

// ---- 2. Express Middleware ----
app.use(bodyParser.urlencoded({ extended: true }));
app.use(bodyParser.json());
app.use(express.static('public')); // Serve static files (index.html, etc.)

// ---- 3. Start server AFTER DB connects ----
async function startServer() {
  try {
    await client.connect();
    console.log("Connected to MongoDB");

    // ---- 4. API Endpoint: Search Listings ----
    app.get('/api/listings', async (req, res, next) => {
      try {
        const db = client.db("sample_airbnb");
        const collection = db.collection("listingsAndReviews");
        const filter = {};

        // If id is given, return only that listing (for bookings page)
        if (req.query.id) {
          const id = req.query.id;
          let objId;
          try {
            objId = id.length === 24 ? new ObjectId(id) : id;
          } catch {
            objId = id; // fallback if not an ObjectId
          }
          const listing = await collection.find({ _id: objId }, {
            projection: {
              name: 1,
              summary: 1,
              price: 1,
              "review_scores.review_scores_rating": 1,
              _id: 1
            }
          }).toArray();
          return res.json(listing);
        }

        // --- RANDOM listings if no filters provided (homepage load) ---
        if (!req.query.location && !req.query.propertyType && !req.query.bedrooms) {
          const listings = await collection.aggregate([
            { $sample: { size: 10 } },
            {
              $project: {
                name: 1,
                summary: 1,
                price: 1,
                "review_scores.review_scores_rating": 1,
                _id: 1
              }
            }
          ]).toArray();
          return res.json(listings);
        }

        // Otherwise, use filters for search
        if (req.query.location) {
          filter['address.market'] = { $regex: req.query.location, $options: 'i' };
        }
        if (req.query.propertyType) {
          filter.property_type = req.query.propertyType;
        }
        if (req.query.bedrooms) {
          if (req.query.bedrooms === '5plus') {
            filter.bedrooms = { $gte: 5 };
          } else {
            filter.bedrooms = parseInt(req.query.bedrooms);
          }
        }

        // Filtered search (sorted by rating, max 20)
        const listings = await collection.find(filter, {
          projection: {
            name: 1,
            summary: 1,
            price: 1,
            "review_scores.review_scores_rating": 1,
            _id: 1
          }
        })
        .sort({ "review_scores.review_scores_rating": -1 })
        .limit(20)
        .toArray();

        res.json(listings);

      } catch (err) {
        next(err);
      }
    });

    // ---- 5. API endpoint: handle booking form POST ----
    app.post('/api/bookings', async (req, res, next) => {
      try {
        const booking = req.body;
        const db = client.db("sample_airbnb");
        const bookingsCol = db.collection("bookings");
    
        // Make sure startDate and endDate are present
        if (!booking.startDate || !booking.endDate) {
          return res.json({ success: false, error: "Missing start or end date." });
        }
    
        // Convert to ISO strings to ensure proper comparison
        const newStart = new Date(booking.startDate);
        const newEnd = new Date(booking.endDate);
    
        // Check for overlapping bookings for the same listing
        const overlap = await bookingsCol.findOne({
          listing_id: booking.listing_id,
          startDate: { $lte: booking.endDate },
          endDate: { $gte: booking.startDate }
        });
    
        if (overlap) {
          return res.json({
            success: false,
            error: "The selected dates overlap with an existing booking for this property. Please choose another date range."
          });
        }
    
        // No overlap, insert the new booking
        await bookingsCol.insertOne(booking);
        res.json({ success: true });
      } catch (err) {
        res.json({ success: false, error: err.message });
      }
    });    

    // ---- 6. Error Handlers ----
    app.use((req, res, next) => res.status(404).send("Not found"));
    app.use((err, req, res, next) => {
      console.error(err.stack);
      res.status(500).send("Internal Server Error");
    });

    // ---- 7. Start Listening and Open Browser ----
    const PORT = 3000;
    app.listen(PORT, () => {
      console.log(`Server listening on port ${PORT}`);
      open(`http://localhost:${PORT}`);
    });

  } catch (err) {
    console.error("Failed to connect to MongoDB", err);
    process.exit(1);
  }
}

startServer();