const express = require('express');
const router = express.Router();

// Get key metrics trends (revenue, inventory value, GMROI)
router.get('/trends', async (req, res) => {
  const pool = req.app.locals.pool;
  try {
    const [rows] = await pool.query(`
      WITH MonthlyMetrics AS (
        SELECT 
          DATE(CONCAT(pta.year, '-', LPAD(pta.month, 2, '0'), '-01')) as date,
          CAST(COALESCE(SUM(pta.total_revenue), 0) AS DECIMAL(15,3)) as revenue,
          CAST(COALESCE(SUM(pta.total_cost), 0) AS DECIMAL(15,3)) as cost,
          CAST(COALESCE(SUM(pm.inventory_value), 0) AS DECIMAL(15,3)) as inventory_value,
          CASE 
            WHEN SUM(pm.inventory_value) > 0 
            THEN CAST((SUM(pta.total_revenue - pta.total_cost) / SUM(pm.inventory_value)) * 100 AS DECIMAL(15,3))
            ELSE 0 
          END as gmroi
        FROM product_time_aggregates pta
        JOIN product_metrics pm ON pta.pid = pm.pid
        WHERE (pta.year * 100 + pta.month) >= DATE_FORMAT(DATE_SUB(CURDATE(), INTERVAL 12 MONTH), '%Y%m')
        GROUP BY pta.year, pta.month
        ORDER BY date ASC
      )
      SELECT 
        DATE_FORMAT(date, '%b %y') as date,
        revenue,
        inventory_value,
        gmroi
      FROM MonthlyMetrics
    `);

    console.log('Raw metrics trends data:', rows);

    // Transform the data into the format expected by the frontend
    const transformedData = {
      revenue: rows.map(row => ({
        date: row.date,
        value: parseFloat(row.revenue)
      })),
      inventory_value: rows.map(row => ({
        date: row.date,
        value: parseFloat(row.inventory_value)
      })),
      gmroi: rows.map(row => ({
        date: row.date,
        value: parseFloat(row.gmroi)
      }))
    };

    console.log('Transformed metrics data:', transformedData);
    res.json(transformedData);
  } catch (error) {
    console.error('Error fetching metrics trends:', error);
    res.status(500).json({ error: 'Failed to fetch metrics trends' });
  }
});

module.exports = router;