const { outputProgress } = require('./utils/progress');
const { getConnection } = require('./utils/db');

async function calculateVendorMetrics(startTime, totalProducts, processedCount) {
    const connection = await getConnection();
    try {
        outputProgress({
            status: 'running',
            operation: 'Calculating vendor metrics',
            current: Math.floor(totalProducts * 0.7),
            total: totalProducts,
            elapsed: formatElapsedTime(startTime),
            remaining: estimateRemaining(startTime, Math.floor(totalProducts * 0.7), totalProducts),
            rate: calculateRate(startTime, Math.floor(totalProducts * 0.7)),
            percentage: '70'
        });

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

        // Calculate vendor performance metrics
        await connection.query(`
            INSERT INTO vendor_metrics (
                vendor,
                avg_lead_time_days,
                on_time_delivery_rate,
                order_fill_rate,
                total_orders,
                total_late_orders,
                total_purchase_value,
                avg_order_value,
                active_products,
                total_products,
                total_revenue,
                avg_margin_percent,
                status
            )
            WITH vendor_orders AS (
                SELECT 
                    po.vendor,
                    AVG(DATEDIFF(po.received_date, po.date)) as avg_lead_time_days,
                    COUNT(*) as total_orders,
                    COUNT(CASE WHEN po.received_date > po.expected_date THEN 1 END) as total_late_orders,
                    SUM(po.cost_price * po.ordered) as total_purchase_value,
                    AVG(po.cost_price * po.ordered) as avg_order_value,
                    CASE 
                        WHEN COUNT(*) > 0 THEN 
                            (COUNT(CASE WHEN po.received = po.ordered THEN 1 END) * 100.0) / COUNT(*)
                        ELSE 0 
                    END as order_fill_rate
                FROM purchase_orders po
                WHERE po.status = 'closed'
                GROUP BY po.vendor
            ),
            vendor_products AS (
                SELECT 
                    p.vendor,
                    COUNT(DISTINCT p.product_id) as total_products,
                    COUNT(DISTINCT CASE WHEN p.visible = true THEN p.product_id END) as active_products,
                    SUM(o.price * o.quantity) as total_revenue,
                    CASE 
                        WHEN SUM(o.price * o.quantity) > 0 THEN 
                            (SUM((o.price - p.cost_price) * o.quantity) * 100.0) / SUM(o.price * o.quantity)
                        ELSE 0 
                    END as avg_margin_percent
                FROM products p
                LEFT JOIN orders o ON p.product_id = o.product_id AND o.canceled = false
                GROUP BY p.vendor
            )
            SELECT 
                vd.vendor,
                COALESCE(vo.avg_lead_time_days, 0) as avg_lead_time_days,
                CASE 
                    WHEN COALESCE(vo.total_orders, 0) > 0 THEN 
                        ((COALESCE(vo.total_orders, 0) - COALESCE(vo.total_late_orders, 0)) * 100.0) / COALESCE(vo.total_orders, 1)
                    ELSE 0 
                END as on_time_delivery_rate,
                COALESCE(vo.order_fill_rate, 0) as order_fill_rate,
                COALESCE(vo.total_orders, 0) as total_orders,
                COALESCE(vo.total_late_orders, 0) as total_late_orders,
                COALESCE(vo.total_purchase_value, 0) as total_purchase_value,
                COALESCE(vo.avg_order_value, 0) as avg_order_value,
                COALESCE(vp.active_products, 0) as active_products,
                COALESCE(vp.total_products, 0) as total_products,
                COALESCE(vp.total_revenue, 0) as total_revenue,
                COALESCE(vp.avg_margin_percent, 0) as avg_margin_percent,
                vd.status
            FROM vendor_details vd
            LEFT JOIN vendor_orders vo ON vd.vendor = vo.vendor
            LEFT JOIN vendor_products vp ON vd.vendor = vp.vendor
            ON DUPLICATE KEY UPDATE
                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),
                total_orders = VALUES(total_orders),
                total_late_orders = VALUES(total_late_orders),
                total_purchase_value = VALUES(total_purchase_value),
                avg_order_value = VALUES(avg_order_value),
                active_products = VALUES(active_products),
                total_products = VALUES(total_products),
                total_revenue = VALUES(total_revenue),
                avg_margin_percent = VALUES(avg_margin_percent),
                status = VALUES(status),
                last_calculated_at = CURRENT_TIMESTAMP
        `);

        // Calculate vendor 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 vendor_time_data AS (
                SELECT 
                    vd.vendor,
                    YEAR(po.date) as year,
                    MONTH(po.date) as month,
                    COUNT(DISTINCT po.po_id) as total_orders,
                    COUNT(DISTINCT CASE WHEN po.received_date > po.expected_date THEN po.po_id END) as late_orders,
                    AVG(DATEDIFF(po.received_date, po.date)) as avg_lead_time_days,
                    SUM(po.cost_price * po.ordered) as total_purchase_value,
                    SUM(o.price * o.quantity) as total_revenue,
                    CASE 
                        WHEN SUM(o.price * o.quantity) > 0 THEN 
                            (SUM((o.price - p.cost_price) * o.quantity) * 100.0) / SUM(o.price * o.quantity)
                        ELSE 0 
                    END as avg_margin_percent
                FROM vendor_details vd
                LEFT JOIN products p ON vd.vendor = p.vendor
                LEFT JOIN purchase_orders po ON p.product_id = po.product_id
                LEFT JOIN orders o ON p.product_id = o.product_id AND o.canceled = false
                WHERE po.date >= DATE_SUB(CURRENT_DATE, INTERVAL 12 MONTH)
                GROUP BY vd.vendor, YEAR(po.date), MONTH(po.date)
            )
            SELECT 
                vendor,
                year,
                month,
                COALESCE(total_orders, 0) as total_orders,
                COALESCE(late_orders, 0) as late_orders,
                COALESCE(avg_lead_time_days, 0) as avg_lead_time_days,
                COALESCE(total_purchase_value, 0) as total_purchase_value,
                COALESCE(total_revenue, 0) as total_revenue,
                COALESCE(avg_margin_percent, 0) as avg_margin_percent
            FROM vendor_time_data
            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)
        `);

        return Math.floor(totalProducts * 0.75);
    } finally {
        connection.release();
    }
}

module.exports = calculateVendorMetrics;