const { outputProgress, formatElapsedTime, estimateRemaining, calculateRate, logError } = require('./utils/progress');
const { getConnection } = require('./utils/db');

async function calculateFinancialMetrics(startTime, totalProducts, processedCount = 0, isCancelled = false) {
    const connection = await getConnection();
    let success = false;
    const BATCH_SIZE = 5000;
    let myProcessedProducts = 0; // Track products processed *within this module*
    
    try {
        // Get last calculation timestamp
        const [lastCalc] = await connection.query(`
            SELECT last_calculation_timestamp 
            FROM calculate_status 
            WHERE module_name = 'financial_metrics'
        `);
        const lastCalculationTime = lastCalc[0]?.last_calculation_timestamp || '1970-01-01';

        // Get total count of products needing updates
        if (!totalProducts) {
            const [productCount] = await connection.query(`
                SELECT COUNT(DISTINCT p.pid) as count 
                FROM products p
                LEFT JOIN orders o ON p.pid = o.pid AND o.updated > ?
                WHERE p.updated > ?
                   OR o.pid IS NOT NULL
            `, [lastCalculationTime, lastCalculationTime]);
            totalProducts = productCount[0].count;
        }

        if (totalProducts === 0) {
            console.log('No products need financial metric updates');
            return {
                processedProducts: 0,
                processedOrders: 0,
                processedPurchaseOrders: 0,
                success: true
            };
        }

        if (isCancelled) {
            outputProgress({
                status: 'cancelled',
                operation: 'Financial metrics calculation cancelled',
                current: processedCount,
                total: totalProducts,
                elapsed: formatElapsedTime(startTime),
                remaining: null,
                rate: calculateRate(startTime, processedCount),
                percentage: ((processedCount / totalProducts) * 100).toFixed(1),
                timing: {
                    start_time: new Date(startTime).toISOString(),
                    end_time: new Date().toISOString(),
                    elapsed_seconds: Math.round((Date.now() - startTime) / 1000)
                }
            });
            return {
                processedProducts: myProcessedProducts,
                processedOrders: 0,
                processedPurchaseOrders: 0,
                success
            };
        }

        outputProgress({
            status: 'running',
            operation: 'Starting financial metrics calculation',
            current: processedCount,
            total: totalProducts,
            elapsed: formatElapsedTime(startTime),
            remaining: estimateRemaining(startTime, processedCount, totalProducts),
            rate: calculateRate(startTime, processedCount),
            percentage: ((processedCount / totalProducts) * 100).toFixed(1),
            timing: {
                start_time: new Date(startTime).toISOString(),
                end_time: new Date().toISOString(),
                elapsed_seconds: Math.round((Date.now() - startTime) / 1000)
            }
        });

        // Process in batches
        let lastPid = 0;
        while (true) {
            if (isCancelled) break;

            const [batch] = await connection.query(`
                SELECT DISTINCT p.pid 
                FROM products p
                LEFT JOIN orders o ON p.pid = o.pid 
                WHERE p.pid > ?
                  AND (
                      p.updated > ?
                      OR EXISTS (
                          SELECT 1 FROM orders o2 
                          WHERE o2.pid = p.pid 
                          AND o2.updated > ?
                      )
                  )
                ORDER BY p.pid 
                LIMIT ?
            `, [lastPid, lastCalculationTime, lastCalculationTime, BATCH_SIZE]);

            if (batch.length === 0) break;

            // Update financial metrics for this batch
            await connection.query(`
                UPDATE product_metrics pm
                JOIN (
                    SELECT 
                        p.pid,
                        p.cost_price * p.stock_quantity as inventory_value,
                        SUM(o.quantity * o.price) as total_revenue,
                        SUM(o.quantity * p.cost_price) as cost_of_goods_sold,
                        SUM(o.quantity * (o.price - p.cost_price)) as gross_profit,
                        COUNT(DISTINCT DATE(o.date)) as active_days
                    FROM products p
                    LEFT JOIN orders o ON p.pid = o.pid 
                        AND o.canceled = false
                        AND o.date >= DATE_SUB(CURRENT_DATE, INTERVAL 90 DAY)
                    WHERE p.pid IN (?)
                    GROUP BY p.pid
                ) fin ON pm.pid = fin.pid
                SET 
                    pm.inventory_value = COALESCE(fin.inventory_value, 0),
                    pm.total_revenue = COALESCE(fin.total_revenue, 0),
                    pm.cost_of_goods_sold = COALESCE(fin.cost_of_goods_sold, 0),
                    pm.gross_profit = COALESCE(fin.gross_profit, 0),
                    pm.gmroi = CASE 
                        WHEN COALESCE(fin.inventory_value, 0) > 0 AND fin.active_days > 0 
                        THEN (COALESCE(fin.gross_profit, 0) * (365.0 / fin.active_days)) / COALESCE(fin.inventory_value, 0)
                        ELSE 0 
                    END,
                    pm.last_calculated_at = NOW()
            `, [batch.map(row => row.pid)]);

            lastPid = batch[batch.length - 1].pid;
            myProcessedProducts += batch.length;

            outputProgress({
                status: 'running',
                operation: 'Processing financial metrics batch',
                current: processedCount + myProcessedProducts,
                total: totalProducts,
                elapsed: formatElapsedTime(startTime),
                remaining: estimateRemaining(startTime, processedCount + myProcessedProducts, totalProducts),
                rate: calculateRate(startTime, processedCount + myProcessedProducts),
                percentage: (((processedCount + myProcessedProducts) / totalProducts) * 100).toFixed(1),
                timing: {
                    start_time: new Date(startTime).toISOString(),
                    end_time: new Date().toISOString(),
                    elapsed_seconds: Math.round((Date.now() - startTime) / 1000)
                }
            });
        }

        // If we get here, everything completed successfully
        success = true;
        
        // Update calculate_status
        await connection.query(`
            INSERT INTO calculate_status (module_name, last_calculation_timestamp)
            VALUES ('financial_metrics', NOW())
            ON DUPLICATE KEY UPDATE last_calculation_timestamp = NOW()
        `);

        return {
            processedProducts: myProcessedProducts,
            processedOrders: 0,
            processedPurchaseOrders: 0,
            success
        };

    } catch (error) {
        success = false;
        logError(error, 'Error calculating financial metrics');
        throw error;
    } finally {
        if (connection) {
            connection.release();
        }
    }
}

module.exports = calculateFinancialMetrics;