<?php
/* Copyright (C) 2026 ZUGFeRD Import Module
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 */

/**
 * \file    class/zugferdparser.class.php
 * \ingroup importzugferd
 * \brief   Parser for ZUGFeRD/Factur-X XML invoices
 */

/**
 * Class ZugferdParser
 * Parses ZUGFeRD XML from PDF attachments
 */
class ZugferdParser
{
    /**
     * @var DoliDB Database handler
     */
    public $db;

    /**
     * @var string Error message
     */
    public $error = '';

    /**
     * @var array Error messages
     */
    public $errors = array();

    /**
     * @var string XML content
     */
    public $xml_content = '';

    /**
     * @var SimpleXMLElement Parsed XML
     */
    public $xml;

    /**
     * @var array Parsed invoice data
     */
    public $invoice_data = array();

    /**
     * @var array Namespace prefixes
     */
    private $namespaces = array();

    /**
     * Constructor
     *
     * @param DoliDB $db Database handler
     */
    public function __construct($db)
    {
        $this->db = $db;
    }

    /**
     * Extract XML from PDF file
     *
     * @param string $pdf_path Path to PDF file
     * @return int 1 if OK, -1 if error
     */
    public function extractFromPdf($pdf_path)
    {
        if (!file_exists($pdf_path)) {
            $this->error = 'File not found: ' . $pdf_path;
            return -1;
        }

        // Read PDF content
        $pdf_content = file_get_contents($pdf_path);
        if ($pdf_content === false) {
            $this->error = 'Cannot read PDF file';
            return -1;
        }

        // Try to find embedded XML using different methods
        $xml = $this->extractXmlFromPdfContent($pdf_content);

        if (empty($xml)) {
            // Try using pdfdetach command
            $xml = $this->extractXmlUsingPdfdetach($pdf_path);
        }

        if (empty($xml)) {
            $this->error = 'No ZUGFeRD/Factur-X XML found in PDF';
            return -1;
        }

        $this->xml_content = $xml;
        return 1;
    }

    /**
     * Extract XML from PDF content by searching for XML patterns
     *
     * @param string $content PDF binary content
     * @return string|null XML content or null
     */
    private function extractXmlFromPdfContent($content)
    {
        // Look for embedded file streams
        // ZUGFeRD XML typically starts with <?xml and contains CrossIndustryInvoice or CrossIndustryDocument

        // Method 1: Look for FlateDecode streams and decompress
        $pattern = '/stream\s*(.*?)\s*endstream/s';
        preg_match_all($pattern, $content, $matches);

        foreach ($matches[1] as $stream) {
            // Try to decompress
            $decompressed = @gzuncompress($stream);
            if ($decompressed === false) {
                $decompressed = @gzinflate($stream);
            }
            if ($decompressed === false) {
                $decompressed = $stream;
            }

            // Check if it's XML
            if (strpos($decompressed, '<?xml') !== false &&
                (strpos($decompressed, 'CrossIndustryDocument') !== false ||
                 strpos($decompressed, 'CrossIndustryInvoice') !== false)) {
                // Extract just the XML part
                $start = strpos($decompressed, '<?xml');
                $xml = substr($decompressed, $start);
                // Find the end
                if (preg_match('/<\/[a-z]+:CrossIndustry(Document|Invoice)>/i', $xml, $endMatch, PREG_OFFSET_CAPTURE)) {
                    $xml = substr($xml, 0, $endMatch[0][1] + strlen($endMatch[0][0]));
                    return $xml;
                }
            }
        }

        return null;
    }

    /**
     * Extract XML using pdfdetach command line tool
     *
     * @param string $pdf_path Path to PDF
     * @return string|null XML content or null
     */
    private function extractXmlUsingPdfdetach($pdf_path)
    {
        $tmp_file = sys_get_temp_dir() . '/zugferd_' . uniqid() . '.xml';

        // Try to extract first attachment
        $cmd = 'pdfdetach -save 1 -o ' . escapeshellarg($tmp_file) . ' ' . escapeshellarg($pdf_path) . ' 2>&1';
        exec($cmd, $output, $return_code);

        if ($return_code === 0 && file_exists($tmp_file)) {
            $xml = file_get_contents($tmp_file);
            unlink($tmp_file);

            if (strpos($xml, 'CrossIndustryDocument') !== false ||
                strpos($xml, 'CrossIndustryInvoice') !== false) {
                return $xml;
            }
        }

        // Try listing and extracting by name
        $cmd = 'pdfdetach -list ' . escapeshellarg($pdf_path) . ' 2>&1';
        exec($cmd, $list_output, $return_code);

        foreach ($list_output as $line) {
            if (preg_match('/(ZUGFeRD|factur-x|xrechnung)/i', $line)) {
                if (preg_match('/(\d+):/', $line, $matches)) {
                    $idx = $matches[1];
                    $cmd = 'pdfdetach -save ' . $idx . ' -o ' . escapeshellarg($tmp_file) . ' ' . escapeshellarg($pdf_path) . ' 2>&1';
                    exec($cmd, $output, $return_code);

                    if ($return_code === 0 && file_exists($tmp_file)) {
                        $xml = file_get_contents($tmp_file);
                        unlink($tmp_file);
                        return $xml;
                    }
                }
            }
        }

        return null;
    }

    /**
     * Parse the XML content
     *
     * @param string $xml_content Optional XML content, uses $this->xml_content if not provided
     * @return int 1 if OK, -1 if error
     */
    public function parse($xml_content = null)
    {
        if ($xml_content !== null) {
            $this->xml_content = $xml_content;
        }

        if (empty($this->xml_content)) {
            $this->error = 'No XML content to parse';
            return -1;
        }

        libxml_use_internal_errors(true);
        $this->xml = simplexml_load_string($this->xml_content);

        if ($this->xml === false) {
            $errors = libxml_get_errors();
            $this->error = 'XML parse error: ' . ($errors[0]->message ?? 'Unknown error');
            libxml_clear_errors();
            return -1;
        }

        // Get namespaces
        $this->namespaces = $this->xml->getNamespaces(true);

        // Determine ZUGFeRD version and parse accordingly
        if ($this->isZugferdV1()) {
            return $this->parseZugferdV1();
        } elseif ($this->isZugferdV2()) {
            return $this->parseZugferdV2();
        } else {
            $this->error = 'Unknown ZUGFeRD/Factur-X format';
            return -1;
        }
    }

    /**
     * Check if ZUGFeRD v1 format
     *
     * @return bool
     */
    private function isZugferdV1()
    {
        return strpos($this->xml_content, 'CrossIndustryDocument') !== false;
    }

    /**
     * Check if ZUGFeRD v2 / Factur-X format
     *
     * @return bool
     */
    private function isZugferdV2()
    {
        return strpos($this->xml_content, 'CrossIndustryInvoice') !== false;
    }

    /**
     * Parse ZUGFeRD v1 format
     *
     * @return int 1 if OK, -1 if error
     */
    private function parseZugferdV1()
    {
        $this->xml->registerXPathNamespace('rsm', 'urn:ferd:CrossIndustryDocument:invoice:1p0');
        $this->xml->registerXPathNamespace('ram', 'urn:un:unece:uncefact:data:standard:ReusableAggregateBusinessInformationEntity:12');
        $this->xml->registerXPathNamespace('udt', 'urn:un:unece:uncefact:data:standard:UnqualifiedDataType:15');

        $data = array();

        // Header information
        $header = $this->xml->xpath('//rsm:HeaderExchangedDocument');
        if (!empty($header)) {
            $data['invoice_number'] = $this->getXpathValue('//rsm:HeaderExchangedDocument/ram:ID');
            $data['invoice_type'] = $this->getXpathValue('//rsm:HeaderExchangedDocument/ram:TypeCode');
            $data['invoice_name'] = $this->getXpathValue('//rsm:HeaderExchangedDocument/ram:Name');

            $dateStr = $this->getXpathValue('//rsm:HeaderExchangedDocument/ram:IssueDateTime/udt:DateTimeString');
            $data['invoice_date'] = $this->parseDate($dateStr);
        }

        // Seller (Lieferant)
        $data['seller'] = array(
            'name' => $this->getXpathValue('//ram:SellerTradeParty/ram:Name'),
            'global_id' => $this->getXpathValue('//ram:SellerTradeParty/ram:GlobalID'),
            'vat_id' => $this->getXpathValue('//ram:SellerTradeParty/ram:SpecifiedTaxRegistration/ram:ID[@schemeID="VA"]'),
            'address' => array(
                'street' => $this->getXpathValue('//ram:SellerTradeParty/ram:PostalTradeAddress/ram:LineOne'),
                'postcode' => $this->getXpathValue('//ram:SellerTradeParty/ram:PostalTradeAddress/ram:PostcodeCode'),
                'city' => $this->getXpathValue('//ram:SellerTradeParty/ram:PostalTradeAddress/ram:CityName'),
                'country' => $this->getXpathValue('//ram:SellerTradeParty/ram:PostalTradeAddress/ram:CountryID'),
            )
        );

        // Buyer (Käufer - wir)
        $data['buyer'] = array(
            'id' => $this->getXpathValue('//ram:BuyerTradeParty/ram:ID'),
            'reference' => $this->getXpathValue('//ram:ApplicableSupplyChainTradeAgreement/ram:BuyerReference'),
            'name' => $this->getXpathValue('//ram:BuyerTradeParty/ram:Name'),
        );

        // Totals
        $data['totals'] = array(
            'net' => (float) $this->getXpathValue('//ram:SpecifiedTradeSettlementMonetarySummation/ram:LineTotalAmount'),
            'tax' => (float) $this->getXpathValue('//ram:SpecifiedTradeSettlementMonetarySummation/ram:TaxTotalAmount'),
            'gross' => (float) $this->getXpathValue('//ram:SpecifiedTradeSettlementMonetarySummation/ram:GrandTotalAmount'),
            'currency' => $this->getXpathValue('//ram:ApplicableSupplyChainTradeSettlement/ram:InvoiceCurrencyCode'),
        );

        // Due date
        $dueDateStr = $this->getXpathValue('//ram:SpecifiedTradePaymentTerms/ram:DueDateDateTime/udt:DateTimeString');
        $data['due_date'] = $this->parseDate($dueDateStr);

        // Line items
        $data['lines'] = array();
        $lines = $this->xml->xpath('//ram:IncludedSupplyChainTradeLineItem');

        foreach ($lines as $line) {
            $line->registerXPathNamespace('ram', 'urn:un:unece:uncefact:data:standard:ReusableAggregateBusinessInformationEntity:12');

            // Get price and basis quantity for correct unit price calculation
            $chargeAmount = (float) $this->getNodeValue($line->xpath('ram:SpecifiedSupplyChainTradeAgreement/ram:NetPriceProductTradePrice/ram:ChargeAmount'));
            $basisQuantity = (float) $this->getNodeValue($line->xpath('ram:SpecifiedSupplyChainTradeAgreement/ram:NetPriceProductTradePrice/ram:BasisQuantity'));
            $basisQuantityUnit = (string) $this->getNodeAttribute($line->xpath('ram:SpecifiedSupplyChainTradeAgreement/ram:NetPriceProductTradePrice/ram:BasisQuantity'), 'unitCode');

            // Calculate real unit price: if BasisQuantity is e.g. 100 (meters), price is for 100 units
            if ($basisQuantity > 0 && $basisQuantity != 1) {
                $unitPrice = $chargeAmount / $basisQuantity;
            } else {
                $unitPrice = $chargeAmount;
            }

            // Extract copper surcharge (Kupferzuschlag) from AppliedTradeAllowanceCharge
            $copperSurcharge = null;
            $copperSurchargeBasisQty = null;
            $allowanceCharges = $line->xpath('ram:SpecifiedSupplyChainTradeAgreement/ram:GrossPriceProductTradePrice/ram:AppliedTradeAllowanceCharge');
            foreach ($allowanceCharges as $charge) {
                $charge->registerXPathNamespace('ram', 'urn:un:unece:uncefact:data:standard:ReusableAggregateBusinessInformationEntity:12');
                $reason = (string) $this->getNodeValue($charge->xpath('ram:Reason'));
                if (stripos($reason, 'Kupfer') !== false || stripos($reason, 'copper') !== false || stripos($reason, 'Metall') !== false) {
                    $copperSurcharge = (float) $this->getNodeValue($charge->xpath('ram:ActualAmount'));
                    $copperSurchargeBasisQty = (float) $this->getNodeValue($charge->xpath('ram:BasisQuantity'));
                    break;
                }
            }

            // Also check ApplicableProductCharacteristic for copper surcharge
            if ($copperSurcharge === null) {
                $characteristics = $line->xpath('ram:SpecifiedTradeProduct/ram:ApplicableProductCharacteristic');
                foreach ($characteristics as $char) {
                    $char->registerXPathNamespace('ram', 'urn:un:unece:uncefact:data:standard:ReusableAggregateBusinessInformationEntity:12');
                    $desc = (string) $this->getNodeValue($char->xpath('ram:Description'));
                    if (stripos($desc, 'Kupfer') !== false || stripos($desc, 'copper') !== false || stripos($desc, 'Metall') !== false) {
                        $copperSurcharge = (float) $this->getNodeValue($char->xpath('ram:Value'));
                        // Usually refers to same basis quantity as the price
                        $copperSurchargeBasisQty = $basisQuantity ?: 1;
                        break;
                    }
                }
            }

            // Calculate copper surcharge per single unit
            $copperSurchargePerUnit = null;
            if ($copperSurcharge !== null && $copperSurcharge > 0) {
                if ($copperSurchargeBasisQty > 0 && $copperSurchargeBasisQty != 1) {
                    $copperSurchargePerUnit = $copperSurcharge / $copperSurchargeBasisQty;
                } else {
                    $copperSurchargePerUnit = $copperSurcharge;
                }
            }

            $lineData = array(
                'line_id' => (string) $this->getNodeValue($line->xpath('ram:AssociatedDocumentLineDocument/ram:LineID')),
                'product' => array(
                    'seller_id' => (string) $this->getNodeValue($line->xpath('ram:SpecifiedTradeProduct/ram:SellerAssignedID')),
                    'buyer_id' => (string) $this->getNodeValue($line->xpath('ram:SpecifiedTradeProduct/ram:BuyerAssignedID')),
                    'global_id' => (string) $this->getNodeValue($line->xpath('ram:SpecifiedTradeProduct/ram:GlobalID')),
                    'name' => (string) $this->getNodeValue($line->xpath('ram:SpecifiedTradeProduct/ram:Name')),
                    'description' => (string) $this->getNodeValue($line->xpath('ram:SpecifiedTradeProduct/ram:Description')),
                ),
                'quantity' => (float) $this->getNodeValue($line->xpath('ram:SpecifiedSupplyChainTradeDelivery/ram:BilledQuantity')),
                'unit_code' => (string) $this->getNodeAttribute($line->xpath('ram:SpecifiedSupplyChainTradeDelivery/ram:BilledQuantity'), 'unitCode'),
                'unit_price' => $unitPrice,
                'unit_price_raw' => $chargeAmount,
                'basis_quantity' => $basisQuantity ?: 1,
                'basis_quantity_unit' => $basisQuantityUnit,
                'line_total' => (float) $this->getNodeValue($line->xpath('ram:SpecifiedSupplyChainTradeSettlement/ram:SpecifiedTradeSettlementMonetarySummation/ram:LineTotalAmount')),
                'tax_percent' => (float) $this->getNodeValue($line->xpath('ram:SpecifiedSupplyChainTradeSettlement/ram:ApplicableTradeTax/ram:ApplicablePercent')),
                // Copper surcharge data
                'copper_surcharge' => $copperSurcharge,
                'copper_surcharge_basis_qty' => $copperSurchargeBasisQty,
                'copper_surcharge_per_unit' => $copperSurchargePerUnit,
            );

            $data['lines'][] = $lineData;
        }

        $this->invoice_data = $data;
        return 1;
    }

    /**
     * Parse ZUGFeRD v2 / Factur-X format
     *
     * @return int 1 if OK, -1 if error
     */
    private function parseZugferdV2()
    {
        $this->xml->registerXPathNamespace('rsm', 'urn:un:unece:uncefact:data:standard:CrossIndustryInvoice:100');
        $this->xml->registerXPathNamespace('ram', 'urn:un:unece:uncefact:data:standard:ReusableAggregateBusinessInformationEntity:100');
        $this->xml->registerXPathNamespace('qdt', 'urn:un:unece:uncefact:data:standard:QualifiedDataType:100');
        $this->xml->registerXPathNamespace('udt', 'urn:un:unece:uncefact:data:standard:UnqualifiedDataType:100');

        $data = array();

        // Header information
        $data['invoice_number'] = $this->getXpathValue('//rsm:ExchangedDocument/ram:ID');
        $data['invoice_type'] = $this->getXpathValue('//rsm:ExchangedDocument/ram:TypeCode');
        $data['invoice_name'] = $this->getXpathValue('//rsm:ExchangedDocument/ram:Name');

        $dateStr = $this->getXpathValue('//rsm:ExchangedDocument/ram:IssueDateTime/udt:DateTimeString');
        $data['invoice_date'] = $this->parseDate($dateStr);

        // Seller (Lieferant)
        $data['seller'] = array(
            'name' => $this->getXpathValue('//ram:ApplicableHeaderTradeAgreement/ram:SellerTradeParty/ram:Name'),
            'global_id' => $this->getXpathValue('//ram:ApplicableHeaderTradeAgreement/ram:SellerTradeParty/ram:GlobalID'),
            'vat_id' => $this->getXpathValue('//ram:ApplicableHeaderTradeAgreement/ram:SellerTradeParty/ram:SpecifiedTaxRegistration/ram:ID'),
            'address' => array(
                'street' => $this->getXpathValue('//ram:ApplicableHeaderTradeAgreement/ram:SellerTradeParty/ram:PostalTradeAddress/ram:LineOne'),
                'postcode' => $this->getXpathValue('//ram:ApplicableHeaderTradeAgreement/ram:SellerTradeParty/ram:PostalTradeAddress/ram:PostcodeCode'),
                'city' => $this->getXpathValue('//ram:ApplicableHeaderTradeAgreement/ram:SellerTradeParty/ram:PostalTradeAddress/ram:CityName'),
                'country' => $this->getXpathValue('//ram:ApplicableHeaderTradeAgreement/ram:SellerTradeParty/ram:PostalTradeAddress/ram:CountryID'),
            )
        );

        // Buyer (Käufer - wir)
        $data['buyer'] = array(
            'id' => $this->getXpathValue('//ram:ApplicableHeaderTradeAgreement/ram:BuyerTradeParty/ram:ID'),
            'reference' => $this->getXpathValue('//ram:ApplicableHeaderTradeAgreement/ram:BuyerReference'),
            'name' => $this->getXpathValue('//ram:ApplicableHeaderTradeAgreement/ram:BuyerTradeParty/ram:Name'),
        );

        // Totals
        $data['totals'] = array(
            'net' => (float) $this->getXpathValue('//ram:ApplicableHeaderTradeSettlement/ram:SpecifiedTradeSettlementHeaderMonetarySummation/ram:LineTotalAmount'),
            'tax' => (float) $this->getXpathValue('//ram:ApplicableHeaderTradeSettlement/ram:SpecifiedTradeSettlementHeaderMonetarySummation/ram:TaxTotalAmount'),
            'gross' => (float) $this->getXpathValue('//ram:ApplicableHeaderTradeSettlement/ram:SpecifiedTradeSettlementHeaderMonetarySummation/ram:GrandTotalAmount'),
            'currency' => $this->getXpathValue('//ram:ApplicableHeaderTradeSettlement/ram:InvoiceCurrencyCode'),
        );

        // Due date
        $dueDateStr = $this->getXpathValue('//ram:SpecifiedTradePaymentTerms/ram:DueDateDateTime/udt:DateTimeString');
        $data['due_date'] = $this->parseDate($dueDateStr);

        // Line items
        $data['lines'] = array();
        $lines = $this->xml->xpath('//ram:IncludedSupplyChainTradeLineItem');

        foreach ($lines as $line) {
            $line->registerXPathNamespace('ram', 'urn:un:unece:uncefact:data:standard:ReusableAggregateBusinessInformationEntity:100');

            // Get price and basis quantity for correct unit price calculation
            $chargeAmount = (float) $this->getNodeValue($line->xpath('ram:SpecifiedLineTradeAgreement/ram:NetPriceProductTradePrice/ram:ChargeAmount'));
            $basisQuantity = (float) $this->getNodeValue($line->xpath('ram:SpecifiedLineTradeAgreement/ram:NetPriceProductTradePrice/ram:BasisQuantity'));
            $basisQuantityUnit = (string) $this->getNodeAttribute($line->xpath('ram:SpecifiedLineTradeAgreement/ram:NetPriceProductTradePrice/ram:BasisQuantity'), 'unitCode');

            // Calculate real unit price: if BasisQuantity is e.g. 100 (meters), price is for 100 units
            if ($basisQuantity > 0 && $basisQuantity != 1) {
                $unitPrice = $chargeAmount / $basisQuantity;
            } else {
                $unitPrice = $chargeAmount;
            }

            // Extract copper surcharge (Kupferzuschlag) from AppliedTradeAllowanceCharge (v2)
            $copperSurcharge = null;
            $copperSurchargeBasisQty = null;
            $allowanceCharges = $line->xpath('ram:SpecifiedLineTradeAgreement/ram:GrossPriceProductTradePrice/ram:AppliedTradeAllowanceCharge');
            foreach ($allowanceCharges as $charge) {
                $charge->registerXPathNamespace('ram', 'urn:un:unece:uncefact:data:standard:ReusableAggregateBusinessInformationEntity:100');
                $reason = (string) $this->getNodeValue($charge->xpath('ram:Reason'));
                if (stripos($reason, 'Kupfer') !== false || stripos($reason, 'copper') !== false || stripos($reason, 'Metall') !== false) {
                    $copperSurcharge = (float) $this->getNodeValue($charge->xpath('ram:ActualAmount'));
                    $copperSurchargeBasisQty = (float) $this->getNodeValue($charge->xpath('ram:BasisQuantity'));
                    break;
                }
            }

            // Also check ApplicableProductCharacteristic for copper surcharge (v2)
            if ($copperSurcharge === null) {
                $characteristics = $line->xpath('ram:SpecifiedTradeProduct/ram:ApplicableProductCharacteristic');
                foreach ($characteristics as $char) {
                    $char->registerXPathNamespace('ram', 'urn:un:unece:uncefact:data:standard:ReusableAggregateBusinessInformationEntity:100');
                    $desc = (string) $this->getNodeValue($char->xpath('ram:Description'));
                    if (stripos($desc, 'Kupfer') !== false || stripos($desc, 'copper') !== false || stripos($desc, 'Metall') !== false) {
                        $copperSurcharge = (float) $this->getNodeValue($char->xpath('ram:Value'));
                        $copperSurchargeBasisQty = $basisQuantity ?: 1;
                        break;
                    }
                }
            }

            // Calculate copper surcharge per single unit
            $copperSurchargePerUnit = null;
            if ($copperSurcharge !== null && $copperSurcharge > 0) {
                if ($copperSurchargeBasisQty > 0 && $copperSurchargeBasisQty != 1) {
                    $copperSurchargePerUnit = $copperSurcharge / $copperSurchargeBasisQty;
                } else {
                    $copperSurchargePerUnit = $copperSurcharge;
                }
            }

            $lineData = array(
                'line_id' => (string) $this->getNodeValue($line->xpath('ram:AssociatedDocumentLineDocument/ram:LineID')),
                'product' => array(
                    'seller_id' => (string) $this->getNodeValue($line->xpath('ram:SpecifiedTradeProduct/ram:SellerAssignedID')),
                    'buyer_id' => (string) $this->getNodeValue($line->xpath('ram:SpecifiedTradeProduct/ram:BuyerAssignedID')),
                    'global_id' => (string) $this->getNodeValue($line->xpath('ram:SpecifiedTradeProduct/ram:GlobalID')),
                    'name' => (string) $this->getNodeValue($line->xpath('ram:SpecifiedTradeProduct/ram:Name')),
                    'description' => (string) $this->getNodeValue($line->xpath('ram:SpecifiedTradeProduct/ram:Description')),
                ),
                'quantity' => (float) $this->getNodeValue($line->xpath('ram:SpecifiedLineTradeDelivery/ram:BilledQuantity')),
                'unit_code' => (string) $this->getNodeAttribute($line->xpath('ram:SpecifiedLineTradeDelivery/ram:BilledQuantity'), 'unitCode'),
                'unit_price' => $unitPrice,
                'unit_price_raw' => $chargeAmount,
                'basis_quantity' => $basisQuantity ?: 1,
                'basis_quantity_unit' => $basisQuantityUnit,
                'line_total' => (float) $this->getNodeValue($line->xpath('ram:SpecifiedLineTradeSettlement/ram:SpecifiedTradeSettlementLineMonetarySummation/ram:LineTotalAmount')),
                'tax_percent' => (float) $this->getNodeValue($line->xpath('ram:SpecifiedLineTradeSettlement/ram:ApplicableTradeTax/ram:RateApplicablePercent')),
                // Copper surcharge data
                'copper_surcharge' => $copperSurcharge,
                'copper_surcharge_basis_qty' => $copperSurchargeBasisQty,
                'copper_surcharge_per_unit' => $copperSurchargePerUnit,
            );

            $data['lines'][] = $lineData;
        }

        $this->invoice_data = $data;
        return 1;
    }

    /**
     * Get value from XPath result
     *
     * @param string $xpath XPath expression
     * @return string
     */
    private function getXpathValue($xpath)
    {
        $result = $this->xml->xpath($xpath);
        if (!empty($result)) {
            return trim((string) $result[0]);
        }
        return '';
    }

    /**
     * Get value from node array
     *
     * @param array $nodes XPath result array
     * @return string
     */
    private function getNodeValue($nodes)
    {
        if (!empty($nodes) && isset($nodes[0])) {
            return trim((string) $nodes[0]);
        }
        return '';
    }

    /**
     * Get attribute from node
     *
     * @param array $nodes XPath result array
     * @param string $attr Attribute name
     * @return string
     */
    private function getNodeAttribute($nodes, $attr)
    {
        if (!empty($nodes) && isset($nodes[0])) {
            $attributes = $nodes[0]->attributes();
            if (isset($attributes[$attr])) {
                return (string) $attributes[$attr];
            }
        }
        return '';
    }

    /**
     * Parse date string in format YYYYMMDD or ISO
     *
     * @param string $dateStr Date string
     * @return string Date in Y-m-d format
     */
    private function parseDate($dateStr)
    {
        if (empty($dateStr)) {
            return '';
        }

        // Format: YYYYMMDD
        if (preg_match('/^(\d{4})(\d{2})(\d{2})$/', $dateStr, $matches)) {
            return $matches[1] . '-' . $matches[2] . '-' . $matches[3];
        }

        // Format: YYYY-MM-DD or ISO
        if (preg_match('/^(\d{4})-(\d{2})-(\d{2})/', $dateStr, $matches)) {
            return $matches[1] . '-' . $matches[2] . '-' . $matches[3];
        }

        return $dateStr;
    }

    /**
     * Get file hash for duplicate detection
     *
     * @param string $file_path Path to file
     * @return string SHA256 hash
     */
    public function getFileHash($file_path)
    {
        if (!file_exists($file_path)) {
            return '';
        }
        return hash_file('sha256', $file_path);
    }

    /**
     * Get invoice data
     *
     * @return array
     */
    public function getInvoiceData()
    {
        return $this->invoice_data;
    }

    /**
     * Get XML content
     *
     * @return string
     */
    public function getXmlContent()
    {
        return $this->xml_content;
    }
}