// 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 a millisecond timestamp into "M/D/YY @HH:mm" 24-hr in 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(',', ' @');
}
// NOAA heat-index formula
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 & period
function getShiftInfo(epoch) {
  const estNow = new Date(epoch).toLocaleString('en-US',{timeZone:'America/New_York'});
  const d = new Date(estNow);
  const h = d.getHours(), m = d.getMinutes();
  let shift, start = new Date(d);
  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:d };
}
// Fetch weather
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:`${zip},us`, appid:key, units:'imperial' } }
    );
    const desc = data.weather[0].description.replace(/^\w/,c=>c.toUpperCase());
    return `${desc}. Hi of ${Math.round(data.main.temp_max)}, Humidity ${data.main.humidity}%`;
  } catch(e){
    console.error('Weather API error',e.message);
    return 'Unavailable';
  }
}

// ─── MariaDB Pool ─────────────────────────────────────────────────────────────
const pool = mysql.createPool({
  host:            process.env.DB_HOST,
  port:            +process.env.DB_PORT||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 table exists (no-op if already ran above)
(async()=>{
  await pool.execute(`
    CREATE TABLE IF NOT EXISTS readings (
      id INT 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
    );
  `);
})();

// ─── 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(evt,data){
  const msg = `event: ${evt}\ndata: ${JSON.stringify(data)}\n\n`;
  clients.forEach(c=>c.write(msg));
}

// ─── Dual Dock‐Door 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 both readings
    const ins = `
      INSERT INTO readings(location,stationDockDoor,epoch_ms,temperature,humidity,heatIndex)
      VALUES(?,?,?,?,?,?)`;
    await pool.execute(ins,['Inbound', String(inD), epoch, inT, inH, hiIn]);
    await pool.execute(ins,['Outbound',String(outD), epoch,outT,outH,hiOut]);

    // broadcast 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
    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(e); }

    // Slack
    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(err);
    res.status(500).json({ error: err.message });
  }
});

// ─── Area/Mod 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, 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});

    // CSV
    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(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(err);
    res.status(500).json({ error: err.message });
  }
});

// ─── Fetch & Export ─────────────────────────────────────────────────────────
app.get('/api/readings', async (req,res)=>{
  const [rows] = await pool.execute(`SELECT * FROM readings ORDER BY epoch_ms`);
  res.json(rows);
});
app.get('/api/export', async (req,res)=>{
  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();
});

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