const express = require('express');
const { Pool } = require('pg');
const cors = require('cors');
require('dotenv').config();

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

const pool = new Pool({
  user: process.env.DB_USER || 'admin',
  host: process.env.DB_HOST || 'localhost',
  database: process.env.DB_NAME || 'sop_monitoring',
  password: process.env.DB_PASS || 'password',
  port: process.env.DB_PORT || 5432,
});

app.get('/api/changeovers', async (req, res) => {
  try {
    const result = await pool.query('SELECT DISTINCT changeover_id, changeover_date FROM events ORDER BY changeover_date DESC');
    res.json(result.rows);
  } catch (err) {
    console.error(err);
    res.status(500).json({ error: 'Internal Server Error' });
  }
});

app.get('/api/events', async (req, res) => {
  try {
    const { camera_zone, state, changeover_id } = req.query;
    let query = 'SELECT * FROM events WHERE 1=1';
    let values = [];
    
    if (camera_zone) {
      values.push(camera_zone);
      query += ` AND camera_zone = $${values.length}`;
    }
    if (state) {
      values.push(state);
      query += ` AND state = $${values.length}`;
    }
    if (changeover_id) {
      values.push(changeover_id);
      query += ` AND changeover_id = $${values.length}`;
    }
    query += ' ORDER BY start_time ASC';
    
    const result = await pool.query(query, values);
    res.json(result.rows);
  } catch (err) {
    console.error(err);
    res.status(500).json({ error: 'Internal Server Error' });
  }
});

app.get('/api/analytics/idle-time', async (req, res) => {
  try {
    const { changeover_id } = req.query;
    let filter = changeover_id ? `AND changeover_id = $1` : '';
    let params = changeover_id ? [changeover_id] : [];

    // 1. CO Idle Time: Sum of all events marked Waste in CO
    const coResult = await pool.query(`
      SELECT SUM(state_duration_seconds) as total_idle
      FROM events
      WHERE camera_zone = 'CO' AND state = 'Waste' ${filter}
    `, params);
    const coIdle = parseInt(coResult.rows[0].total_idle || 0);

    // 2. Mill Idle Time: Sum of Waste in Mill + specific Mill gap/idle
    const millResult = await pool.query(`
      SELECT SUM(state_duration_seconds) as total_idle
      FROM events
      WHERE camera_zone = 'Mill' AND (state = 'Waste' OR state = 'Idle') ${filter}
    `, params);
    const millIdle = parseInt(millResult.rows[0].total_idle || 0);

    // 3. Conveyor Idle Time: Sum of No Load (Waste) + Load waiting before start
    const conveyorResult = await pool.query(`
      SELECT SUM(state_duration_seconds) as total_idle
      FROM events
      WHERE camera_zone = 'Conveyor' AND (state = 'Waste' OR state = 'Load waiting') ${filter}
    `, params);
    const conveyorIdle = parseInt(conveyorResult.rows[0].total_idle || 0);

    res.json({
      CO: coIdle,
      Mill: millIdle,
      Conveyor: conveyorIdle
    });
  } catch (err) {
    console.error(err);
    res.status(500).json({ error: 'Internal Server Error' });
  }
});

app.get('/api/analytics/bottlenecks', async (req, res) => {
  try {
    const { changeover_id } = req.query;
    let filter = changeover_id ? `AND changeover_id = $1` : '';
    let params = changeover_id ? [changeover_id] : [];

    const result = await pool.query(`
      SELECT event_description, camera_zone, SUM(state_duration_seconds) as total_duration, COUNT(*) as occurrences
      FROM events
      WHERE state IN ('Waste', 'Idle', 'Load waiting') ${filter}
      GROUP BY event_description, camera_zone
      ORDER BY total_duration DESC
      LIMIT 10
    `, params);
    res.json(result.rows);
  } catch (err) {
    console.error(err);
    res.status(500).json({ error: 'Internal Server Error' });
  }
});

app.get('/api/analytics/sop-compliance', async (req, res) => {
  try {
    const { changeover_id } = req.query;
    let filter = changeover_id ? `AND changeover_id = $1` : '';
    let params = changeover_id ? [changeover_id] : [];

    // 1. Conveyor must be started 15 mins before changeover
    const coStartResult = await pool.query(`SELECT start_time FROM events WHERE camera_zone = 'CO' ${filter} ORDER BY start_time ASC LIMIT 1`, params);
    const convStartResult = await pool.query(`SELECT start_time FROM events WHERE camera_zone = 'Conveyor' AND (event_description ILIKE '%Started%' OR event_description ILIKE '%Active%') ${filter} ORDER BY start_time ASC LIMIT 1`, params);
    
    let conveyorCompliance = { rule: "Conveyor started 15 min before CO", status: "Unknown", detail: "" };
    if (coStartResult.rows.length > 0 && convStartResult.rows.length > 0) {
      const coTime = coStartResult.rows[0].start_time;
      const convTime = convStartResult.rows[0].start_time;
      // Compare times (assuming same day)
      const coDate = new Date(`1970-01-01T${coTime}Z`);
      const convDate = new Date(`1970-01-01T${convTime}Z`);
      const diffMins = (coDate - convDate) / 60000;
      
      if (diffMins >= 15) {
        conveyorCompliance.status = "Pass";
        conveyorCompliance.detail = `Started ${diffMins.toFixed(1)} mins before CO`;
      } else {
        conveyorCompliance.status = "Fail";
        if (diffMins > 0) conveyorCompliance.detail = `Started only ${diffMins.toFixed(1)} mins before CO`;
        else conveyorCompliance.detail = `Started ${Math.abs(diffMins).toFixed(1)} mins AFTER CO`;
      }
    }

    // 2. Mill should be completed within 15 mins after pushout rubber collection
    const pushoutResult = await pool.query(`SELECT end_time FROM events WHERE event_description ILIKE '%Pushout of Rubber - 4%' ${filter} ORDER BY end_time DESC LIMIT 1`, params);
    const millCompleteResult = await pool.query(`SELECT end_time FROM events WHERE camera_zone = 'Mill' AND event_description ILIKE '%Sheeting Out - 3%' ${filter} ORDER BY end_time DESC LIMIT 1`, params);
    
    let millCompliance = { rule: "Mill completed within 15 min of Pushout", status: "Unknown", detail: "" };
    if (pushoutResult.rows.length > 0 && millCompleteResult.rows.length > 0) {
      const pushoutTime = pushoutResult.rows[0].end_time;
      const millTime = millCompleteResult.rows[0].end_time;
      const pushoutDate = new Date(`1970-01-01T${pushoutTime}Z`);
      const millDate = new Date(`1970-01-01T${millTime}Z`);
      const diffMins = (millDate - pushoutDate) / 60000;
      
      if (diffMins <= 15 && diffMins >= 0) {
        millCompliance.status = "Pass";
        millCompliance.detail = `Completed in ${diffMins.toFixed(1)} mins`;
      } else {
        millCompliance.status = "Fail";
        millCompliance.detail = `Completed in ${diffMins.toFixed(1)} mins (limit 15)`;
      }
    }

    res.json([conveyorCompliance, millCompliance]);
  } catch (err) {
    console.error(err);
    res.status(500).json({ error: 'Internal Server Error' });
  }
});

const PORT = process.env.PORT || 3000;
app.listen(PORT, () => {
  console.log(`Server running on port ${PORT}`);
});