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

    $barcode = trim($data['barcode'] ?? '');

    if (!$barcode) {
        $answer['message'] = 'No barcode provided.';
        http_response_code(400);
        exit(json_encode($answer));
    }

    function findProduct(PDO $pdo, int $company_id, string $sku): array|false {
        $sth = $pdo->prepare(
            "SELECT sku, product_name, uom
             FROM md_product
             WHERE company_id = :company_id
               AND sku = :sku
               AND status > 0
             LIMIT 1"
        );
        $sth->execute([':company_id' => $company_id, ':sku' => $sku]);
        return $sth->fetch(PDO::FETCH_ASSOC);
    }

    function validateLotSerial(PDO $pdo, int $company_id, string $sku, string $lot, string $serial): void {
        if ($serial === '') return;

        $warehouses = $pdo->prepare(
            "SELECT id FROM md_warehouse
             WHERE company_id = :company_id AND status = 1"
        );
        $warehouses->execute([':company_id' => $company_id]);

        foreach ($warehouses->fetchAll(PDO::FETCH_COLUMN) as $warehouse_id) {
            $table = 'td_stock_' . (int)$warehouse_id;
            $sth = $pdo->prepare(
                "SELECT lot_number
                 FROM `{$table}`
                 WHERE company_id = :company_id
                   AND product_sku = :sku
                   AND serial_number = :serial
                   AND status != -1
                 LIMIT 1"
            );
            $sth->execute([':company_id' => $company_id, ':sku' => $sku, ':serial' => $serial]);
            $existing_lot = $sth->fetchColumn();
            if ($existing_lot !== false && (string)$existing_lot !== $lot) {
                throw new Exception('Serial number belongs to a different lot.');
            }
        }
    }

    function findPreparedLabel(PDO $pdo, int $company_id, string $barcode, string $type): array|false {
        $sth = $pdo->prepare(
            "SELECT *
             FROM md_barcode
             WHERE company_id = :company_id
               AND barcode = :barcode
               AND barcode_type = :barcode_type
             LIMIT 1"
        );
        $sth->execute([
            ':company_id'   => $company_id,
            ':barcode'      => $barcode,
            ':barcode_type' => $type,
        ]);
        $row = $sth->fetch(PDO::FETCH_ASSOC);
        if ($row && (int)$row['status'] !== 1) {
            throw new Exception('Barcode is disabled.');
        }
        return $row ?: false;
    }

    function advancedLocation(PDO $pdo, int $company_id): bool {
        $sth = $pdo->prepare(
            "SELECT value FROM company_setting
             WHERE company_id = :company_id AND setting_key = 'advanced_location'
             LIMIT 1"
        );
        $sth->execute([':company_id' => $company_id]);
        $value = $sth->fetchColumn();
        return (int)($value === false ? 0 : $value) === 1;
    }

    function validateLocation(PDO $pdo, int $company_id, int $warehouse_id, string $zone, string $aisle, string $rack): void {
        $sth = $pdo->prepare(
            "SELECT 1 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'       => $rack,
        ]);
        if (!$sth->fetchColumn()) throw new Exception('Location not found.');
    }

    $parts = explode('|', $barcode);
    $label_type = strtoupper($parts[0] ?? '');

    try {
        if ($label_type === 'SKU') {
            if (count($parts) !== 4) throw new Exception('Invalid SKU label format.');
            $sku = trim($parts[1]);
            $lot = trim($parts[2]);
            $serial = trim($parts[3]);
            if ($sku === '' || $lot === '' || $serial === '') throw new Exception('SKU, lot, and serial are required.');

            $label = findPreparedLabel($pdo2, $company_id, $barcode, 'sku');
            if (!$label) throw new Exception('SKU barcode label was not prepared.');
            if ($label['product_sku'] !== $sku || $label['lot_number'] !== $lot || $label['serial_number'] !== $serial) {
                throw new Exception('SKU barcode label does not match its registry.');
            }

            $product = findProduct($pdo2, $company_id, $sku);
            if (!$product) throw new Exception('SKU not found.');
            validateLotSerial($pdo2, $company_id, $sku, $lot, $serial);

            $answer['success']       = 1;
            $answer['type']          = 'sku';
            $answer['sku']           = $product['sku'];
            $answer['product_name']  = $product['product_name'];
            $answer['uom']           = $product['uom'] ?? 'pcs';
            $answer['lot_number']    = $lot;
            $answer['serial_number'] = $serial;
            exit(json_encode($answer));
        }

        if ($label_type === 'LOC') {
            $advanced = advancedLocation($pdo1, $company_id);
            if ($advanced && count($parts) !== 5) throw new Exception('Invalid advanced location label format.');
            if (!$advanced && count($parts) !== 3) throw new Exception('Invalid location label format.');

            $warehouse_id = (int)($parts[1] ?? 0);
            if ($advanced) {
                $zone = trim($parts[2]);
                $aisle = trim($parts[3]);
                $rack = trim($parts[4]);
            } else {
                $rack = trim($parts[2]);
                $zone = $rack;
                $aisle = $rack;
            }
            if (!$warehouse_id || $zone === '' || $aisle === '' || $rack === '') throw new Exception('Location label is incomplete.');

            $label = findPreparedLabel($pdo2, $company_id, $barcode, 'loc');
            if (!$label) throw new Exception('Location barcode label was not prepared.');
            if ((int)$label['warehouse_id'] !== $warehouse_id || $label['zone'] !== $zone || $label['aisle'] !== $aisle || $label['rack'] !== $rack) {
                throw new Exception('Location barcode label does not match its registry.');
            }

            validateLocation($pdo2, $company_id, $warehouse_id, $zone, $aisle, $rack);

            $answer['success']      = 1;
            $answer['type']         = 'loc';
            $answer['warehouse_id'] = $warehouse_id;
            $answer['zone']         = $zone;
            $answer['aisle']        = $aisle;
            $answer['rack']         = $rack;
            exit(json_encode($answer));
        }
    } catch (Exception $e) {
        $answer['message'] = $e->getMessage();
        http_response_code(400);
        exit(json_encode($answer));
    }

    $sth = $pdo2->prepare(
        "SELECT sku, product_name, uom
         FROM md_product
         WHERE company_id = :company_id
           AND (barcode = :barcode OR sku = :sku)
           AND status > 0
         ORDER BY (barcode = :barcode_order) DESC
         LIMIT 1"
    );
    $sth->execute([
        ':company_id'    => $company_id,
        ':barcode'       => $barcode,
        ':sku'           => $barcode,
        ':barcode_order' => $barcode,
    ]);
    $product = $sth->fetch(PDO::FETCH_ASSOC);

    if (!$product) {
        $answer['message'] = 'Barcode not found.';
        http_response_code(404);
        exit(json_encode($answer));
    }

    $answer['success']      = 1;
    $answer['type']         = 'raw';
    $answer['sku']          = $product['sku'];
    $answer['product_name'] = $product['product_name'];
    $answer['uom']          = $product['uom'] ?? 'pcs';
    exit(json_encode($answer));
?>