// 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 JS Date in EST as SQL DATETIME
function formatDateEST(date) {
  const pad = n => n.toString().padStart(2,'0');
  return `${date.getFullYear()}-${pad(date.getMonth()+1)}-${pad(date.getDate())} ` +
         `${pad(date.getHours())}:${pad(date.getMinutes())}:${pad(date.getSeconds())}`;
}

// Format a JS Date in EST as an ISO-like string (no Z)
function isoStringEST(date) {
  const pad = n => n.toString().padStart(2,'0');
  return `${date.getFullYear()}-${pad(date.getMonth()+1)}-${pad(date.getDate())}` +
         `T${pad(date.getHours())}:${pad(date.getMinutes())}:${pad(date.getSeconds())}`;
}

// Compute heat index (NOAA 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 shift (Day/Night), shiftStart, key & estNow in EST
function getShiftInfo(now) {
  const estNow = new Date(now.toLocaleString('en-US',{ timeZone:'America/New_York' }));
  const [h,m] = [estNow.getHours(), estNow.getMinutes()];
  let shift, shiftStart = new Date(estNow);

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

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

// Fetch current weather from OpenWeatherMap
async function fetchCurrentWeather() {
  const apiKey = process.env.WEATHER_API_KEY;
  const zip    = process.env.ZIP_CODE;
  if (!apiKey || !zip) return null;
  try {
    const { data } = await axios.get(
      'https://api.openweathermap.org/data/2.5/weather',
      { params: { zip:`${zip},us`, appid:apiKey, units:'imperial' } }
    );
    return {
      description: data.weather[0].description,
      humidity:    data.main.humidity,
      temperature: data.main.temp
    };
  } catch (err) {
    console.error('Weather API error:', err.message);
    return null;
  }
}

/** MariaDB pool **/
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,
  enableKeepAlive:    true,
  keepAliveInitialDelay:10000
});

// Ensure readings table exists (for dock doors & areas)
(async ()=>{
  const createSQL = `
    CREATE TABLE IF NOT EXISTS readings (
      id INT AUTO_INCREMENT PRIMARY KEY,
      dockDoor    INT,
      direction   VARCHAR(10),
      region      VARCHAR(20),
      stationCode VARCHAR(10),
      timestamp   DATETIME NOT NULL,
      temperature DOUBLE,
      humidity    DOUBLE,
      heatIndex   DOUBLE
    );
  `;
  await pool.execute(createSQL);
})();

/** SSE for real-time updates **/
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));
}

// Middleware & static
app.use(bodyParser.json());
app.use(express.static(path.join(__dirname,'public')));

/** Dual-dock-door readings **/
app.post('/api/readings',async(req,res)=>{
  try {
    const { inbound={}, outbound={} } = req.body;
    const { dockDoor: inDoor, temperature: inTemp, humidity: inHum } = inbound;
    const { dockDoor: outDoor,temperature: outTemp,humidity: outHum } = outbound;
    if ([inDoor,inTemp,inHum,outDoor,outTemp,outHum].some(v=>v===undefined))
      return res.status(400).json({error:'Missing inbound/outbound fields'});

    const hiIn  = computeHeatIndex(inTemp,inHum);
    const hiOut = computeHeatIndex(outTemp,outHum);
    const { shift, shiftStart, key, estNow } = getShiftInfo(new Date());
    shiftCounters[key]=(shiftCounters[key]||0)+1;
    const period = shiftCounters[key];

    const sqlTs = formatDateEST(estNow);
    const bcTs  = isoStringEST(estNow);

    // Insert dock readings
    const insertSQL = `
      INSERT INTO readings
        (dockDoor,direction,timestamp,temperature,humidity,heatIndex)
      VALUES (?,?,?,?,?,?)
    `;
    await pool.execute(insertSQL,[inDoor,'inbound',sqlTs,inTemp,inHum,hiIn]);
    await pool.execute(insertSQL,[outDoor,'outbound',sqlTs,outTemp,outHum,hiOut]);

    // Broadcast SSE
    broadcast('new-reading',{ dockDoor:inDoor, direction:'inbound',timestamp:bcTs,
      temperature:inTemp, humidity:inHum, heatIndex:hiIn });
    broadcast('new-reading',{ dockDoor:outDoor,direction:'outbound',timestamp:bcTs,
      temperature:outTemp,humidity:outHum,heatIndex:hiOut });

    // Build CSV & upload
    const dateKey = `${estNow.getFullYear()}${String(estNow.getMonth()+1).padStart(2,'0')}${String(estNow.getDate()).padStart(2,'0')}`;
    const [rows]  = await pool.execute(
      `SELECT * FROM readings WHERE DATE(timestamp)=CURDATE() ORDER BY timestamp ASC`
    );
    let csvUrl=null;
    try{ csvUrl = await uploadTrendsCsv(dateKey,rows); }
    catch(e){ console.error('CSV upload error:',e); }

    // Weather
    const weather = await fetchCurrentWeather();

    // Slack payload
    const slackPayload = {
      text:                'New temperature readings recorded',
      inbound_dockDoor:    inDoor,
      inbound_temperature: inTemp,
      inbound_humidity:    inHum,
      hiIn,
      outbound_dockDoor:   outDoor,
      outbound_temperature:outTemp,
      outbound_humidity:   outHum,
      hiOut,
      shift,
      period,
      timestamp:           bcTs,
      csvUrl,
      current_weather:     weather?.description    || null,
      current_humidity:    weather?.humidity       || null,
      current_temperature: weather?.temperature    || null
    };
    await axios.post(process.env.SLACK_WEBHOOK_URL,slackPayload);

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

/** Area (A-Mod / AFE-1 / AFE-2 / B-Mod) readings **/
app.post('/api/area-readings',async(req,res)=>{
  try {
    const { area, stationCode, temperature, humidity } = req.body;
    if (!area||!stationCode||temperature==null||humidity==null)
      return res.status(400).json({error:'Missing area,stationCode,temp,humidity'});

    const hi = computeHeatIndex(temperature,humidity);
    const { shift, shiftStart, key, estNow } = getShiftInfo(new Date());
    shiftCounters[key]=(shiftCounters[key]||0)+1;
    const period = shiftCounters[key];
    const sqlTs = formatDateEST(estNow);
    const bcTs  = isoStringEST(estNow);

    // Insert area reading
    const sql = `
      INSERT INTO readings
        (region,stationCode,timestamp,temperature,humidity,heatIndex)
      VALUES (?,?,?,?,?,?)
    `;
    await pool.execute(sql,[area,stationCode,sqlTs,temperature,humidity,hi]);

    // Broadcast SSE
    broadcast('new-area-reading',{ region:area,stationCode,timestamp:bcTs,
      temperature,humidity,heatIndex:hi });

    // Build CSV & upload
    const dateKey = `${estNow.getFullYear()}${String(estNow.getMonth()+1).padStart(2,'0')}${String(estNow.getDate()).padStart(2,'0')}`;
    const [rows]  = await pool.execute(
      `SELECT * FROM readings WHERE DATE(timestamp)=CURDATE() ORDER BY timestamp ASC`
    );
    let csvUrl=null;
    try{ csvUrl = await uploadTrendsCsv(dateKey,rows); }
    catch(e){ console.error('CSV upload error:',e); }

    // Weather
    const weather = await fetchCurrentWeather();

    // Slack payload
    const slackPayload = {
      text:                 'New area temperature reading',
      area,
      stationCode,
      temperature,
      humidity,
      heatIndex:           hi,
      shift,
      period,
      timestamp:            bcTs,
      csvUrl,
      current_weather:      weather?.description    || null,
      current_humidity:     weather?.humidity       || null,
      current_temperature:  weather?.temperature    || null
    };
    await axios.post(process.env.SLACK_WEBHOOK_URL,slackPayload);

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

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

/** Export CSV of all readings **/
app.get('/api/export',async(req,res)=>{
  try {
    const [rows] = await pool.execute(`SELECT * FROM readings ORDER BY timestamp ASC`);
    res.setHeader('Content-disposition','attachment; filename=readings.csv');
    res.set('Content-Type','text/csv');
    res.write('id,dockDoor,direction,region,stationCode,timestamp,temperature,humidity,heatIndex\n');
    rows.forEach(r=>{
      const ts = r.timestamp instanceof Date ? formatDateEST(r.timestamp) : r.timestamp;
      res.write(`${r.id},${r.dockDoor||''},${r.direction||''},${r.region||''},${r.stationCode||''},${ts},${r.temperature},${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}`);
});