require('dotenv').config();
const express = require('express');
const cors = require('cors');
const { MongoClient, ObjectId } = require('mongodb');

const app = express();
app.use(cors());
app.use(express.json());

// Statische Dateien (z.B. global.js, CSS) ausliefern
app.use(express.static('public'));

// Pug als Template Engine einrichten
app.set('view engine', 'pug');
app.set('views', './views');

const PORT = process.env.PORT || 3000;
const MONGO_URI = process.env.MONGO_URI || 'mongodb://localhost:27017';
const DB_NAME = process.env.DB_NAME || 'espdb';

let db, entriesCollection;

// MongoDB-Verbindung herstellen
async function initMongo() {
  const client = new MongoClient(MONGO_URI);
  await client.connect();
  db = client.db(DB_NAME);
  entriesCollection = db.collection('entries');
  console.log(`MongoDB verbunden: ${MONGO_URI}/${DB_NAME}`);
}
initMongo().catch(err => {
  console.error('MongoDB Verbindungsfehler:', err);
  process.exit(1);
});

function formatDate(date) {
  const d = new Date(date);
  const year = d.getFullYear();
  const month = String(d.getMonth() + 1).padStart(2, '0');
  const day = String(d.getDate()).padStart(2, '0');
  return `${year}-${month}-${day}`;
}

// --- Web-Seite (Pug) rendern ---
app.get('/', (req, res) => {
  res.render('index');
});

// --- API ---
app.post('/api/save', async (req, res) => {
  const { espId, sensorNumber } = req.body;
  if (!espId || !sensorNumber) {
    return res.status(400).json({ ok: false, error: 'ESP-ID und Sensornummer sind erforderlich' });
  }
  try {
    const doc = {
      espId: String(espId).trim(),
      sensorNumber: String(sensorNumber).trim(),
      createdAt: new Date()
    };
    const result = await entriesCollection.insertOne(doc);
    return res.json({ ok: true, id: result.insertedId, entry: doc });
  } catch (err) {
    console.error(err);
    return res.status(500).json({ ok: false, error: 'DB Fehler' });
  }
});

app.get('/api/list', async (req, res) => {
  const page = Math.max(1, parseInt(req.query.page) || 1);
  const limit = Math.max(1, Math.min(100, parseInt(req.query.limit) || 50));
  try {
    const total = await entriesCollection.countDocuments();
    const rawItems = await entriesCollection.find({})
      .sort({ createdAt: -1 })
      .skip((page - 1) * limit)
      .limit(limit)
      .toArray();
    const items = rawItems.map(it => ({
      ...it,
      createdAt: formatDate(it.createdAt)
    }));
    return res.json({ ok: true, page, limit, total, items });
  } catch (err) {
    console.error(err);
    return res.status(500).json({ ok: false, error: 'DB Fehler' });
  }
});

app.delete('/api/entry/:id', async (req, res) => {
  try {
    await entriesCollection.deleteOne({ _id: new ObjectId(req.params.id) });
    return res.json({ ok: true });
  } catch (err) {
    console.error(err);
    return res.status(500).json({ ok: false });
  }
});

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