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

    require_role($user_role, ['owner', 'admin', 'staff']);

    $whMgmt = new WarehouseManager($pdo2, $company_id);

    $mode         = $data['mode'] ?? '';
    $warehouse_id = (int)($data['warehouse_id'] ?? 0);
    $zone         = trim($data['zone'] ?? '');
    $aisle        = trim($data['aisle'] ?? '');
    $rack         = trim($data['rack'] ?? '');
    $product_sku  = trim($data['product_sku'] ?? '');
    $lot_number   = trim($data['lot_number'] ?? '');
    $serial       = trim($data['serial_number'] ?? '');

    if (!$warehouse_id || $zone === '' || $aisle === '' || $rack === '') {
        $answer['message'] = 'Location label is incomplete.';
        http_response_code(400);
        exit(json_encode($answer));
    }

    function rackRow(PDO $pdo, int $company_id, int $warehouse_id, string $zone, string $aisle, string $rack): array|false {
        $sth = $pdo->prepare(
            "SELECT id, product_sku, td_stock_id
             FROM md_rack
             WHERE company_id = :company_id
               AND warehouse = :warehouse
               AND zone = :zone
               AND aisle = :aisle
               AND rack = :rack
             LIMIT 1"
        );
        $sth->execute([
            ':company_id' => $company_id,
            ':warehouse'  => $warehouse_id,
            ':zone'       => $zone,
            ':aisle'      => $aisle,
            ':rack'       => $rack,
        ]);
        return $sth->fetch(PDO::FETCH_ASSOC);
    }

    try {
        $rack_row = rackRow($pdo2, $company_id, $warehouse_id, $zone, $aisle, $rack);
        if (!$rack_row) throw new Exception("Location {$zone}-{$aisle}-{$rack} does not exist.");

        if ($mode === 'in' || $mode === 'to') {
            if ($rack_row['product_sku'] !== null) {
                throw new Exception("Location {$zone}-{$aisle}-{$rack} is already occupied by {$rack_row['product_sku']}.");
            }

            if ($mode === 'in' && $product_sku !== '') {
                $whMgmt->validateStockUnique($product_sku, $lot_number ?: null, $serial ?: null);
            }
        } elseif ($mode === 'out' || $mode === 'from') {
            if ($product_sku === '') throw new Exception('Scan the SKU label first.');

            $stock = $whMgmt->getRackStock($warehouse_id, $zone, $aisle, $rack);
            if (!$stock) {
                throw new Exception("Location {$zone}-{$aisle}-{$rack} has no approved stock to move out.");
            }

            if ($stock['product_sku'] !== $product_sku) {
                throw new Exception("Location holds {$stock['product_sku']}, not {$product_sku}.");
            }

            if ($lot_number !== '' && (string)$stock['lot_number'] !== $lot_number) {
                throw new Exception("Location holds lot '{$stock['lot_number']}', not '{$lot_number}'.");
            }

            if ($serial !== '' && (string)$stock['serial_number'] !== $serial) {
                throw new Exception("Location holds serial '{$stock['serial_number']}', not '{$serial}'.");
            }
        } else {
            throw new Exception('Invalid scan validation mode.');
        }

        $answer['success'] = 1;
        exit(json_encode($answer));
    } catch (Exception $e) {
        $answer['message'] = $e->getMessage();
        http_response_code(400);
        exit(json_encode($answer));
    }
?>