// server.js
require('dotenv').config();
const express    = require('express');
const mysql      = require('mysql2/promise');
const bodyParser = require('body-parser');
const path       = require('path');
const axios      = require('axios');
const { uploadTrendsCsv } = require('./s3');

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

// In‐memory shift counters
const shiftCounters = {};

// ─── Helpers ─────────────────────────────────────────────────────────────────
// Format an epoch ms timestamp for Slack: "M/D/YY @HH:mm" in America/New_York
function formatForSlack(epoch) {
  return new Date(epoch).toLocaleString('en-US', {
    timeZone:  'America/New_York',
    month:     'numeric',
    day:       'numeric',
    year:      '2-digit',
    hour12:    false,
    hour:      '2-digit',
    minute:    '2-digit'
  }).replace(',', ' @');
}

// Compute NOAA heat‐index
function computeHeatIndex(T, R) {
  const [c1,c2,c3,c4,c5,c6,c7,c8,c9] = [
    -42.379, 2.04901523, 10.14333127, -0.22475541,
    -0.00683783, -0.05481717, 0.00122874, 0.00085282, -0.00000199
  ];
  const HI = c1 + c2*T + c3*R + c4*T*R
           + c5*T*T + c6*R*R + c7*T*T*R
           + c8*T*R*R + c9*T*T*R*R;
  return Math.round(HI * 100) / 100;
}

// Determine Day/Night shift and rolling period key
function getShiftInfo(epoch) {
  // first get a string in NY time, then parse back to Date
  const estString = new Date(epoch).toLocaleString('en-US', { timeZone: 'America/New_York' });
  const est = new Date(estString);
  const h = est.getHours(), m = est.getMinutes();
  let shift, start = new Date(est);

  if (h > 7 || (h === 7 && m >= 0)) {
    if (h < 17 || (h === 17 && m < 30)) {
      shift = 'Day';   start.setHours(7,0,0,0);
    } else {
      shift = 'Night'; start.setHours(17,30,0,0);
    }
  } else {
    shift = 'Night';
    start.setDate(start.getDate() - 1);
    start.setHours(17,30,0,0);
  }

  const key = `${shift}-${start.toISOString().slice(0,10)}-${start.getHours()}${start.getMinutes()}`;
  return { shift, key, estNow: est };
}

// Fetch current weather forecast for Baltimore
async function fetchCurrentWeather() {
  const key = process.env.WEATHER_API_KEY, zip = process.env.ZIP_CODE;
  if (!key || !zip) return 'Unavailable';
  try {
    const { data } = await axios.get(
      'https://api.openweathermap.org/data/2.5/weather',
      { params: { zip: `${zip},us`, appid: key, units: 'imperial' } }
    );
    const desc = data.weather[0].description.replace(/^\w/, c => c.toUpperCase());
    const hi   = Math.round(data.main.temp_max);
    const hum  = data.main.humidity;
    return `${desc}. Hi of ${hi}, Humidity ${hum}%`;
  } catch (e) {
    console.error('Weather API error:', e.message);
    return 'Unavailable';
  }
}

// ─── MariaDB Pool & Table Setup ───────────────────────────────────────────────
const pool = mysql.createPool({
  host:               process.env.DB_HOST,
  port:               parseInt(process.env.DB_PORT,10) || 3306,
  user:               process.env.DB_USER,
  password:           process.env.DB_PASSWORD,
  database:           process.env.DB_NAME,
  waitForConnections: true,
  connectionLimit:    10,
  queueLimit:         0,
  connectTimeout:     10000
});

// Ensure readings table exists (with epoch_ms instead of timestamp)
(async () => {
  await pool.execute(`
    CREATE TABLE IF NOT EXISTS readings (
      id                INT       NOT NULL AUTO_INCREMENT PRIMARY KEY,
      location          VARCHAR(20) NOT NULL,
      stationDockDoor   VARCHAR(10) NOT NULL,
      epoch_ms          BIGINT    NOT NULL,
      temperature       DOUBLE,
      humidity          DOUBLE,
      heatIndex         DOUBLE,
      INDEX idx_time    (epoch_ms),
      INDEX idx_loc     (location)
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
  `);
})();

// ─── Middleware & Static ─────────────────────────────────────────────────────
app.use(bodyParser.json());
app.use(express.static(path.join(__dirname,'public'), { index: 'heatmap.html' }));

// ─── SSE Setup ────────────────────────────────────────────────────────────────
let clients = [];
app.get('/api/stream', (req, res) => {
  res.set({
    'Content-Type':  'text/event-stream',
    'Cache-Control': 'no-cache',
    Connection:      'keep-alive'
  });
  res.flushHeaders();
  clients.push(res);
  req.on('close', () => { clients = clients.filter(c => c !== res); });
});
function broadcast(event, data) {
  const msg = `event: ${event}\ndata: ${JSON.stringify(data)}\n\n`;
  clients.forEach(c => c.write(msg));
}

// ─── Dual Dock-Door Readings Endpoint ─────────────────────────────────────────
app.post('/api/readings', async (req, res) => {
  try {
    const { inbound = {}, outbound = {} } = req.body;
    const { dockDoor: inD, temperature: inT, humidity: inH } = inbound;
    const { dockDoor: outD, temperature: outT, humidity: outH } = outbound;
    if ([inD, inT, inH, outD, outT, outH].some(v => v == null)) {
      return res.status(400).json({ error: 'Missing fields' });
    }

    const epoch = Date.now();
    const hiIn  = computeHeatIndex(inT, inH);
    const hiOut = computeHeatIndex(outT, outH);
    const { shift, key, estNow } = getShiftInfo(epoch);
    shiftCounters[key] = (shiftCounters[key] || 0) + 1;
    const period = shiftCounters[key];

    // Insert inbound + outbound
    const sql = `
      INSERT INTO readings(location,stationDockDoor,epoch_ms,temperature,humidity,heatIndex)
      VALUES (?, ?, ?, ?, ?, ?)
    `;
    await pool.execute(sql, ['Inbound',  String(inD), epoch, inT, inH, hiIn]);
    await pool.execute(sql, ['Outbound', String(outD), epoch, outT, outH, hiOut]);

    // Broadcast via SSE
    const slackTs = formatForSlack(epoch);
    broadcast('new-reading', {
      location: 'Inbound',
      stationDockDoor: String(inD),
      timestamp: slackTs,
      temperature: inT,
      humidity: inH,
      heatIndex: hiIn
    });
    broadcast('new-reading', {
      location: 'Outbound',
      stationDockDoor: String(outD),
      timestamp: slackTs,
      temperature: outT,
      humidity: outH,
      heatIndex: hiOut
    });

    // CSV upload for today's readings
    const y = estNow.getFullYear(), m = pad2(estNow.getMonth()+1), d = pad2(estNow.getDate());
    const dateKey = `${y}${m}${d}`;
    const [rows] = await pool.execute(
      `SELECT * FROM readings WHERE DATE(FROM_UNIXTIME(epoch_ms/1000)) = CURDATE() ORDER BY epoch_ms`
    );
    let csvUrl = null;
    try { csvUrl = await uploadTrendsCsv(dateKey, rows); }
    catch (e) { console.error('CSV upload error:', e); }

    // Send Slack notification
    const weather = await fetchCurrentWeather();
    const text =
      `*_${shift} shift Period ${period} dock/trailer temperature checks for ${slackTs}_*\n` +
      `*_Current Weather Forecast for Baltimore: ${weather}_*\n\n` +
      `*_⬇️ Inbound Dock Door 🚛 :_* ${inD}\n` +
      `*_Temp:_* ${inT} °F 🌡️\n` +
      `*_Humidity:_* ${inH} % 💦\n` +
      `*_Heat Index:_* ${hiIn} °F 🥵\n\n` +
      `*_⬆️ Outbound Dock Door 🚛 :_* ${outD}\n` +
      `*_Temp:_* ${outT} °F 🌡️\n` +
      `*_Humidity:_* ${outH} % 💦\n` +
      `*_Heat Index:_* ${hiOut} °F 🥵`;

    await axios.post(
      process.env.SLACK_WEBHOOK_URL,
      { text },
      { headers: { 'Content-Type': 'application/json' } }
    );

    res.json({ success: true, shift, period, csvUrl });
  } catch (err) {
    console.error('POST /api/readings error:', err);
    res.status(500).json({ error: err.message });
  }
});

// ─── Area/Mod Station Readings Endpoint ───────────────────────────────────────
app.post('/api/area-readings', async (req, res) => {
  try {
    const { area, stationCode, temperature: T, humidity: H } = req.body;
    if (!area || !stationCode || T == null || H == null) {
      return res.status(400).json({ error: 'Missing fields' });
    }

    const epoch = Date.now();
    const hi = computeHeatIndex(T, H);
    const { shift, key, estNow } = getShiftInfo(epoch);

    await pool.execute(
      `INSERT INTO readings(location,stationDockDoor,epoch_ms,temperature,humidity,heatIndex)
       VALUES (?, ?, ?, ?, ?, ?)`,
      [area, stationCode, epoch, T, H, hi]
    );

    const slackTs = formatForSlack(epoch);
    broadcast('new-area-reading', {
      location: area,
      stationDockDoor: stationCode,
      timestamp: slackTs,
      temperature: T,
      humidity: H,
      heatIndex: hi
    });

    const y = estNow.getFullYear(), m = pad2(estNow.getMonth()+1), d = pad2(estNow.getDate());
    const dateKey = `${y}${m}${d}`;
    const [rows] = await pool.execute(
      `SELECT * FROM readings WHERE DATE(FROM_UNIXTIME(epoch_ms/1000)) = CURDATE() ORDER BY epoch_ms`
    );
    let csvUrl = null;
    try { csvUrl = await uploadTrendsCsv(dateKey, rows); }
    catch (e) { console.error('CSV upload error:', e); }

    const weather = await fetchCurrentWeather();
    const text =
      `*_${shift} shift ${area} temp check for ${slackTs}_*\n` +
      `*_Current Weather Forecast for Baltimore: ${weather}_*\n\n` +
      `*_${area.toUpperCase()} station:_* ${stationCode}\n` +
      `*_Temp:_* ${T} °F 🌡️\n` +
      `*_Humidity:_* ${H} % 💦\n` +
      `*_Heat Index:_* ${hi} °F 🥵`;

    await axios.post(
      process.env.SLACK_WEBHOOK_URL,
      { text },
      { headers: { 'Content-Type': 'application/json' } }
    );

    res.json({ success: true, csvUrl });
  } catch (err) {
    console.error('POST /api/area-readings error:', err);
    res.status(500).json({ error: err.message });
  }
});

// ─── Fetch All Readings ────────────────────────────────────────────────────────
app.get('/api/readings', async (req, res) => {
  try {
    const [rows] = await pool.execute(`SELECT * FROM readings ORDER BY epoch_ms`);
    res.json(rows);
  } catch (err) {
    console.error('GET /api/readings error:', err);
    res.status(500).json({ error: err.message });
  }
});

// ─── Export CSV ───────────────────────────────────────────────────────────────
app.get('/api/export', async (req, res) => {
  try {
    const [rows] = await pool.execute(`SELECT * FROM readings ORDER BY epoch_ms`);
    res.setHeader('Content-disposition', 'attachment; filename=readings.csv');
    res.set('Content-Type', 'text/csv');
    res.write('id,location,stationDockDoor,epoch_ms,temperature,humidity,heatIndex\n');
    rows.forEach(r => {
      res.write(`${r.id},${r.location},${r.stationDockDoor},${r.epoch_ms},${r.temperature},${r.humidity},${r.heatIndex}\n`);
    });
    res.end();
  } catch (err) {
    console.error('GET /api/export error:', err);
    res.status(500).send(err.message);
  }
});

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

// Utility pad2 used above
function pad2(n) {
  return n.toString().padStart(2,'0');
}