<?php
    session_start();
    require '../../../assets/utils/db_auth.php';
    require '../../../assets/utils/classes/WarehouseManager.php';

    // Returns active lots for a given product_sku
    // "Active" = EXISTS in an occupied md_rack (product_sku IS NOT NULL)
    $product_sku = $data['product_sku'] ?? '';

    if (empty($product_sku)) {
        $answer['output']  = [];
        $answer['success'] = 1;
        exit(json_encode($answer));
    }

    // Discover all warehouses
    $sth = $pdo2->prepare(
        "SELECT id, warehouse_name FROM md_warehouse
         WHERE company_id = :company_id AND status = 1"
    );
    $sth->execute([':company_id' => $company_id]);
    $warehouses = $sth->fetchAll(PDO::FETCH_ASSOC);

    $active_lots = [];

    foreach ($warehouses as $wh) {
        $safe  = preg_replace('/[^a-zA-Z0-9_]/', '', $wh['warehouse_name']);
        $table = "td_stock_{$safe}";

        $sth = $pdo2->prepare(
            "SELECT DISTINCT s.lot_number, l.expiry_date
             FROM `{$table}` s
             LEFT JOIN md_lot l
                 ON l.company_id  = s.company_id
                 AND l.product_sku = s.product_sku
                 AND l.lot_number  = s.lot_number
             WHERE s.company_id  = :company_id
               AND s.product_sku = :product_sku
               AND s.type        = 'in'
               AND s.lot_number  IS NOT NULL
               AND EXISTS (
                   SELECT 1 FROM md_rack r
                   WHERE r.company_id  = s.company_id
                     AND r.td_stock_id = s.id
                     AND r.product_sku IS NOT NULL
               )"
        );
        $sth->execute([
            ':company_id'  => $company_id,
            ':product_sku' => $product_sku,
        ]);

        foreach ($sth->fetchAll(PDO::FETCH_ASSOC) as $row) {
            $key = $row['lot_number'];
            if (!isset($active_lots[$key])) {
                $active_lots[$key] = $row;
            }
        }
    }

    $answer['output']  = array_values($active_lots);
    $answer['success'] = 1;
    exit(json_encode($answer));
?>