// server.js — minimal Web Push backend.
//
// Setup:
//   npm init -y
//   npm install express web-push
//   npx web-push generate-vapid-keys      # paste the two keys below
//   node server.js
//
// Serves the static test page from ./public, stores subscriptions in memory,
// and exposes /api/send to push to every stored subscription.

const express = require('express');
const webpush = require('web-push');
const path = require('path');

const app = express();
app.use(express.json());
app.use(express.static(path.join(__dirname, 'public')));

// --- VAPID keys -----------------------------------------------------------
// Paste the output of `npx web-push generate-vapid-keys` here.

const VAPID_PUBLIC  = 'BDjn64xCA8SGTAZy8Tes-Kqm44sgFTyZlgXRfpeKvUjSSFdnfI4ru0jY64JExOlfV4qNke7kqKb6B_sBUmbTdIY';
const VAPID_PRIVATE = 'u2cXEA3HC2FUY7f4FedQNqnAcOeFdfG655WK_ktYWbQ';

webpush.setVapidDetails(
  'mailto:simon@unisolve.com.au',  // contact the push service can reach if there's a problem
  VAPID_PUBLIC,
  VAPID_PRIVATE
);

// Expose the public key so the page can subscribe without hardcoding it.
app.get('/api/vapidPublicKey', (req, res) => res.send(VAPID_PUBLIC));

// --- Subscription store ---------------------------------------------------
// In-memory for testing. Use a real table (one row per device) in production.
const subscriptions = new Map();   // endpoint -> subscription object

app.post('/api/subscribe', (req, res) => {
  const sub = req.body;
  if (!sub || !sub.endpoint) return res.status(400).json({ error: 'bad subscription' });
  subscriptions.set(sub.endpoint, sub);
  console.log('Stored subscription. Total:', subscriptions.size);
  res.status(201).json({ ok: true });
});

// --- Send a push to everyone ----------------------------------------------
// POST /api/send  { "title": "...", "body": "..." }
app.post('/api/send', async (req, res) => {
  const payload = JSON.stringify({
    title: req.body.title || 'Test push',
    body:  req.body.body  || 'Sent from the server at ' + new Date().toLocaleTimeString()
  });

  const results = [];
  for (const [endpoint, sub] of subscriptions) {
    try {
      await webpush.sendNotification(sub, payload);
      results.push({ endpoint, ok: true });
    } catch (err) {
      // 404/410 mean the subscription is dead — drop it so we stop trying.
      if (err.statusCode === 404 || err.statusCode === 410) {
        subscriptions.delete(endpoint);
        results.push({ endpoint, ok: false, removed: true });
      } else {
        results.push({ endpoint, ok: false, status: err.statusCode });
      }
    }
  }
  res.json({ sent: results.length, results });
});

const PORT = process.env.PORT || 8000;
app.listen(PORT, () => console.log(`Listening on http://localhost:${PORT}`));