server.js

require('dotenv').config();
const express = require('express');
const axios = require('axios');
const path = require('path');

const app = express();
const PORT = process.env.PORT || 3000;
const OPENWEATHER_KEY = process.env.OPENWEATHER_KEY;

if (!OPENWEATHER_KEY) {
  console.error('Error: OPENWEATHER_KEY not found in .env');
  process.exit(1);
}

console.log('OpenWeather Key Loaded:', OPENWEATHER_KEY ? 'Yes' : 'No');

// Serve static files from public/
app.use(express.static(path.join(__dirname, 'public')));

// In-memory cache
const cache = {};

// Validate city names
function isValidCity(value) {
  return /^[a-zA-Z0-9\s,.'-]{1,100}$/.test(value);
}

// API endpoint
app.get('/api/weather', async (req, res) => {
  const city = (req.query.city || '').trim();
  if (!isValidCity(city)) {
    return res.status(400).json({ error: 'Invalid city name' });
  }

  const cityKey = city.toLowerCase();

  // Return cached response if available and fresh
  if (cache[cityKey] && Date.now() - cache[cityKey].timestamp < 60_000) {
    return res.json({ ...cache[cityKey].data, fromCache: true });
  }

  try {
    // Use the official OpenWeatherMap API endpoint and the configured key
    const response = await axios.get('https://api.openweathermap.org/data/2.5/weather', {
      params: {
        q: city,
        appid: OPENWEATHER_KEY,
        units: 'metric'
      }
    });

    const data = {
      name: response.data.name,
      country: response.data.sys.country,
      weather: {
        main: response.data.weather[0].main,
        description: response.data.weather[0].description,
        icon: response.data.weather[0].icon
      },
      main: response.data.main,
      wind: response.data.wind
    };

    cache[cityKey] = { data, timestamp: Date.now() };
    res.json(data);

  } catch (err) {
    const status = err.response?.status || 502;
    const msg = err.response?.data?.message || err.message;
    // Provide clearer message when the API key is invalid
    if (status === 401) {
      console.error('OpenWeatherMap API unauthorized (check OPENWEATHER_KEY):', msg);
      return res.status(401).json({ error: 'Invalid OpenWeather API key. Check your OPENWEATHER_KEY in .env' });
    }

    console.error('OpenWeatherMap API error:', status, msg);
    res.status(status).json({ error: `OpenWeatherMap API error: ${msg}` });
  }
});

app.listen(PORT, () => {
  console.log(`Server running at http://localhost:${PORT}`);
});