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

async function calculateVendorMetrics(startTime, totalProducts, processedCount, isCancelled = false) {
    const connection = await getConnection();
    try {
        if (isCancelled) {
            outputProgress({
                status: 'cancelled',
                operation: 'Vendor 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 processedCount;
        }

        outputProgress({
            status: 'running',
            operation: 'Starting vendor 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)
            }
        });

        // First ensure all vendors exist in vendor_details
        await connection.query(`
            INSERT IGNORE INTO vendor_details (vendor, status, created_at, updated_at)
            SELECT DISTINCT 
                vendor,
                'active' as status,
                NOW() as created_at,
                NOW() as updated_at
            FROM products
            WHERE vendor IS NOT NULL
        `);

        processedCount = Math.floor(totalProducts * 0.8);
        outputProgress({
            status: 'running',
            operation: 'Vendor details updated, calculating metrics',
            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)
            }
        });

        if (isCancelled) return processedCount;

        // Now calculate vendor metrics
        await connection.query(`
            INSERT INTO vendor_metrics (
                vendor,
                total_revenue,
                total_orders,
                total_late_orders,
                avg_lead_time_days,
                on_time_delivery_rate,
                order_fill_rate,
                avg_order_value,
                active_products,
                total_products,
                total_purchase_value,
                avg_margin_percent,
                status,
                last_calculated_at
            )
            WITH vendor_sales AS (
                SELECT 
                    p.vendor,
                    SUM(o.quantity * o.price) as total_revenue,
                    COUNT(DISTINCT o.id) as total_orders,
                    COUNT(DISTINCT p.pid) as active_products,
                    SUM(o.quantity * (o.price - p.cost_price)) as total_margin
                FROM products p
                JOIN orders o ON p.pid = o.pid
                WHERE o.canceled = false
                    AND o.date >= DATE_SUB(CURRENT_DATE, INTERVAL 12 MONTH)
                GROUP BY p.vendor
            ),
            vendor_po AS (
                SELECT 
                    p.vendor,
                    COUNT(DISTINCT CASE WHEN po.receiving_status = 40 THEN po.id END) as received_orders,
                    COUNT(DISTINCT po.id) as total_orders,
                    AVG(CASE 
                        WHEN po.receiving_status = 40 
                        THEN DATEDIFF(po.received_date, po.date) 
                    END) as avg_lead_time_days,
                    SUM(po.ordered * po.po_cost_price) as total_purchase_value
                FROM products p
                JOIN purchase_orders po ON p.pid = po.pid
                WHERE po.date >= DATE_SUB(CURRENT_DATE, INTERVAL 12 MONTH)
                GROUP BY p.vendor
            ),
            vendor_products AS (
                SELECT 
                    vendor,
                    COUNT(DISTINCT pid) as total_products
                FROM products
                GROUP BY vendor
            )
            SELECT 
                vs.vendor,
                COALESCE(vs.total_revenue, 0) as total_revenue,
                COALESCE(vp.total_orders, 0) as total_orders,
                COALESCE(vp.total_orders - vp.received_orders, 0) as total_late_orders,
                COALESCE(vp.avg_lead_time_days, 0) as avg_lead_time_days,
                CASE 
                    WHEN vp.total_orders > 0 
                    THEN (vp.received_orders / vp.total_orders) * 100 
                    ELSE 0 
                END as on_time_delivery_rate,
                CASE 
                    WHEN vp.total_orders > 0 
                    THEN (vp.received_orders / vp.total_orders) * 100 
                    ELSE 0 
                END as order_fill_rate,
                CASE 
                    WHEN vs.total_orders > 0 
                    THEN vs.total_revenue / vs.total_orders 
                    ELSE 0 
                END as avg_order_value,
                COALESCE(vs.active_products, 0) as active_products,
                COALESCE(vpr.total_products, 0) as total_products,
                COALESCE(vp.total_purchase_value, 0) as total_purchase_value,
                CASE 
                    WHEN vs.total_revenue > 0 
                    THEN (vs.total_margin / vs.total_revenue) * 100 
                    ELSE 0 
                END as avg_margin_percent,
                'active' as status,
                NOW() as last_calculated_at
            FROM vendor_sales vs
            LEFT JOIN vendor_po vp ON vs.vendor = vp.vendor
            LEFT JOIN vendor_products vpr ON vs.vendor = vpr.vendor
            WHERE vs.vendor IS NOT NULL
            ON DUPLICATE KEY UPDATE
                total_revenue = VALUES(total_revenue),
                total_orders = VALUES(total_orders),
                total_late_orders = VALUES(total_late_orders),
                avg_lead_time_days = VALUES(avg_lead_time_days),
                on_time_delivery_rate = VALUES(on_time_delivery_rate),
                order_fill_rate = VALUES(order_fill_rate),
                avg_order_value = VALUES(avg_order_value),
                active_products = VALUES(active_products),
                total_products = VALUES(total_products),
                total_purchase_value = VALUES(total_purchase_value),
                avg_margin_percent = VALUES(avg_margin_percent),
                status = VALUES(status),
                last_calculated_at = VALUES(last_calculated_at)
        `);

        processedCount = Math.floor(totalProducts * 0.9);
        outputProgress({
            status: 'running',
            operation: 'Vendor metrics calculated, updating time-based metrics',
            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)
            }
        });

        if (isCancelled) return processedCount;

        // Calculate time-based metrics
        await connection.query(`
            INSERT INTO vendor_time_metrics (
                vendor,
                year,
                month,
                total_orders,
                late_orders,
                avg_lead_time_days,
                total_purchase_value,
                total_revenue,
                avg_margin_percent
            )
            WITH monthly_orders AS (
                SELECT 
                    p.vendor,
                    YEAR(o.date) as year,
                    MONTH(o.date) as month,
                    COUNT(DISTINCT o.id) as total_orders,
                    SUM(o.quantity * o.price) as total_revenue,
                    SUM(o.quantity * (o.price - p.cost_price)) as total_margin
                FROM products p
                JOIN orders o ON p.pid = o.pid
                WHERE o.canceled = false
                    AND o.date >= DATE_SUB(CURRENT_DATE, INTERVAL 12 MONTH)
                GROUP BY p.vendor, YEAR(o.date), MONTH(o.date)
            ),
            monthly_po AS (
                SELECT 
                    p.vendor,
                    YEAR(po.date) as year,
                    MONTH(po.date) as month,
                    COUNT(DISTINCT po.id) as total_po,
                    COUNT(DISTINCT CASE 
                        WHEN po.receiving_status = 40 AND po.received_date > po.expected_date 
                        THEN po.id 
                    END) as late_orders,
                    AVG(CASE 
                        WHEN po.receiving_status = 40 
                        THEN DATEDIFF(po.received_date, po.date)
                    END) as avg_lead_time_days,
                    SUM(po.ordered * po.po_cost_price) as total_purchase_value
                FROM products p
                JOIN purchase_orders po ON p.pid = po.pid
                WHERE po.date >= DATE_SUB(CURRENT_DATE, INTERVAL 12 MONTH)
                GROUP BY p.vendor, YEAR(po.date), MONTH(po.date)
            )
            SELECT 
                mo.vendor,
                mo.year,
                mo.month,
                COALESCE(mp.total_po, 0) as total_orders,
                COALESCE(mp.late_orders, 0) as late_orders,
                COALESCE(mp.avg_lead_time_days, 0) as avg_lead_time_days,
                COALESCE(mp.total_purchase_value, 0) as total_purchase_value,
                COALESCE(mo.total_revenue, 0) as total_revenue,
                CASE 
                    WHEN mo.total_revenue > 0 
                    THEN (mo.total_margin / mo.total_revenue) * 100 
                    ELSE 0 
                END as avg_margin_percent
            FROM monthly_orders mo
            LEFT JOIN monthly_po mp ON mo.vendor = mp.vendor 
                AND mo.year = mp.year 
                AND mo.month = mp.month
            ON DUPLICATE KEY UPDATE
                total_orders = VALUES(total_orders),
                late_orders = VALUES(late_orders),
                avg_lead_time_days = VALUES(avg_lead_time_days),
                total_purchase_value = VALUES(total_purchase_value),
                total_revenue = VALUES(total_revenue),
                avg_margin_percent = VALUES(avg_margin_percent)
        `);

        processedCount = Math.floor(totalProducts * 0.95);
        outputProgress({
            status: 'running',
            operation: 'Time-based vendor metrics calculated',
            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)
            }
        });

        return processedCount;
    } catch (error) {
        logError(error, 'Error calculating vendor metrics');
        throw error;
    } finally {
        if (connection) {
            connection.release();
        }
    }
}

module.exports = calculateVendorMetrics;