<?php
/* Copyright (C) 2026 Eduard Wisch <data@data-it-solution.de>
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <https://www.gnu.org/licenses/>.
 */

/**
 * \file    class/zugferdgenerator.class.php
 * \ingroup exportzugferd
 * \brief   ZUGFeRD/Factur-X/XRechnung XML Generator
 */

/**
 * Class ZugferdGenerator
 * Generates EN16931-compliant XML for ZUGFeRD/Factur-X/XRechnung
 */
class ZugferdGenerator
{
	/**
	 * @var DoliDB Database handler
	 */
	private $db;

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

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

	/**
	 * Profile constants
	 */
	const PROFILE_MINIMUM = 'MINIMUM';
	const PROFILE_BASICWL = 'BASIC WL';
	const PROFILE_BASIC = 'BASIC';
	const PROFILE_EN16931 = 'EN16931';
	const PROFILE_EXTENDED = 'EXTENDED';
	const PROFILE_XRECHNUNG = 'XRECHNUNG';

	/**
	 * @var string Current profile
	 */
	private $profile;

	/**
	 * XML Namespaces
	 */
	private $namespaces = array(
		'rsm' => 'urn:un:unece:uncefact:data:standard:CrossIndustryInvoice:100',
		'ram' => 'urn:un:unece:uncefact:data:standard:ReusableAggregateBusinessInformationEntity:100',
		'qdt' => 'urn:un:unece:uncefact:data:standard:QualifiedDataType:100',
		'udt' => 'urn:un:unece:uncefact:data:standard:UnqualifiedDataType:100',
	);

	/**
	 * Constructor
	 *
	 * @param DoliDB $db Database handler
	 */
	public function __construct($db)
	{
		$this->db = $db;
		$this->profile = getDolGlobalString('EXPORTZUGFERD_PROFILE', self::PROFILE_EN16931);
	}

	/**
	 * Generate ZUGFeRD XML from a Dolibarr invoice
	 *
	 * @param Facture $invoice Invoice object
	 * @return string|false XML content or false on error
	 */
	public function generateFromInvoice($invoice)
	{
		global $conf, $mysoc;

		if (empty($invoice->id)) {
			$this->error = 'Invoice ID is empty';
			return false;
		}

		// Fetch invoice data if not already loaded
		if (empty($invoice->lines)) {
			$invoice->fetch_lines();
		}

		// Fetch thirdparty
		if (empty($invoice->thirdparty) || empty($invoice->thirdparty->id)) {
			$invoice->fetch_thirdparty();
		}

		// Start building XML
		$xml = $this->createXMLHeader();
		$xml .= $this->createExchangedDocumentContext();
		$xml .= $this->createExchangedDocument($invoice);
		$xml .= $this->createSupplyChainTradeTransaction($invoice, $mysoc);
		$xml .= $this->createXMLFooter();

		return $xml;
	}

	/**
	 * Create XML header with namespaces
	 *
	 * @return string XML header
	 */
	private function createXMLHeader()
	{
		$xml = '<?xml version="1.0" encoding="UTF-8"?>' . "\n";
		$xml .= '<rsm:CrossIndustryInvoice';
		foreach ($this->namespaces as $prefix => $uri) {
			$xml .= ' xmlns:' . $prefix . '="' . $uri . '"';
		}
		$xml .= '>' . "\n";
		return $xml;
	}

	/**
	 * Create XML footer
	 *
	 * @return string XML footer
	 */
	private function createXMLFooter()
	{
		return '</rsm:CrossIndustryInvoice>' . "\n";
	}

	/**
	 * Create ExchangedDocumentContext element
	 *
	 * @return string XML content
	 */
	private function createExchangedDocumentContext()
	{
		$profileId = $this->getProfileURN();

		$xml = '  <rsm:ExchangedDocumentContext>' . "\n";
		$xml .= '    <ram:GuidelineSpecifiedDocumentContextParameter>' . "\n";
		$xml .= '      <ram:ID>' . $this->xmlEncode($profileId) . '</ram:ID>' . "\n";
		$xml .= '    </ram:GuidelineSpecifiedDocumentContextParameter>' . "\n";
		$xml .= '  </rsm:ExchangedDocumentContext>' . "\n";

		return $xml;
	}

	/**
	 * Get profile URN based on selected profile
	 *
	 * @return string Profile URN
	 */
	private function getProfileURN()
	{
		switch ($this->profile) {
			case self::PROFILE_MINIMUM:
				return 'urn:factur-x.eu:1p0:minimum';
			case self::PROFILE_BASICWL:
				return 'urn:factur-x.eu:1p0:basicwl';
			case self::PROFILE_BASIC:
				return 'urn:cen.eu:en16931:2017#compliant#urn:factur-x.eu:1p0:basic';
			case self::PROFILE_EXTENDED:
				return 'urn:cen.eu:en16931:2017#conformant#urn:factur-x.eu:1p0:extended';
			case self::PROFILE_XRECHNUNG:
				return 'urn:cen.eu:en16931:2017#compliant#urn:xeinkauf.de:kosit:xrechnung_3.0';
			case self::PROFILE_EN16931:
			default:
				return 'urn:cen.eu:en16931:2017';
		}
	}

	/**
	 * Create ExchangedDocument element
	 *
	 * @param Facture $invoice Invoice object
	 * @return string XML content
	 */
	private function createExchangedDocument($invoice)
	{
		$xml = '  <rsm:ExchangedDocument>' . "\n";
		$xml .= '    <ram:ID>' . $this->xmlEncode($invoice->ref) . '</ram:ID>' . "\n";
		$xml .= '    <ram:TypeCode>' . $this->getInvoiceTypeCode($invoice) . '</ram:TypeCode>' . "\n";
		$xml .= '    <ram:IssueDateTime>' . "\n";
		$xml .= '      <udt:DateTimeString format="102">' . date('Ymd', $invoice->date) . '</udt:DateTimeString>' . "\n";
		$xml .= '    </ram:IssueDateTime>' . "\n";

		// Add notes if present
		if (!empty($invoice->note_public)) {
			$xml .= '    <ram:IncludedNote>' . "\n";
			$xml .= '      <ram:Content>' . $this->xmlEncode($invoice->note_public) . '</ram:Content>' . "\n";
			$xml .= '    </ram:IncludedNote>' . "\n";
		}

		$xml .= '  </rsm:ExchangedDocument>' . "\n";

		return $xml;
	}

	/**
	 * Get invoice type code (UNCL 1001)
	 *
	 * @param Facture $invoice Invoice object
	 * @return string Type code
	 */
	private function getInvoiceTypeCode($invoice)
	{
		// 380 = Commercial invoice
		// 381 = Credit note
		// 384 = Corrected invoice
		// 389 = Self-billed invoice
		if ($invoice->type == Facture::TYPE_CREDIT_NOTE) {
			return '381';
		}
		return '380';
	}

	/**
	 * Create SupplyChainTradeTransaction element
	 *
	 * @param Facture  $invoice Invoice object
	 * @param Societe  $mysoc   Seller company
	 * @return string XML content
	 */
	private function createSupplyChainTradeTransaction($invoice, $mysoc)
	{
		$xml = '  <rsm:SupplyChainTradeTransaction>' . "\n";

		// Invoice lines - skip title/subtotal lines with no amount
		$lineNumber = 0;
		foreach ($invoice->lines as $line) {
			// Skip lines that are titles, subtotals, or have zero total and zero price
			// These are typically from subtotaltitle module
			if ($this->isSkippableLine($line)) {
				continue;
			}
			$lineNumber++;
			$xml .= $this->createLineItem($line, $lineNumber);
		}

		// Trade agreement (seller/buyer)
		$xml .= $this->createApplicableHeaderTradeAgreement($invoice, $mysoc);

		// Delivery information
		$xml .= $this->createApplicableHeaderTradeDelivery($invoice);

		// Payment information and totals
		$xml .= $this->createApplicableHeaderTradeSettlement($invoice);

		$xml .= '  </rsm:SupplyChainTradeTransaction>' . "\n";

		return $xml;
	}

	/**
	 * Create line item element
	 *
	 * @param FactureLigne $line       Invoice line
	 * @param int          $lineNumber Line number
	 * @return string XML content
	 */
	private function createLineItem($line, $lineNumber)
	{
		$xml = '    <ram:IncludedSupplyChainTradeLineItem>' . "\n";

		// Line document
		$xml .= '      <ram:AssociatedDocumentLineDocument>' . "\n";
		$xml .= '        <ram:LineID>' . $lineNumber . '</ram:LineID>' . "\n";
		$xml .= '      </ram:AssociatedDocumentLineDocument>' . "\n";

		// Product info
		$xml .= '      <ram:SpecifiedTradeProduct>' . "\n";
		if (!empty($line->product_ref)) {
			$xml .= '        <ram:SellerAssignedID>' . $this->xmlEncode($line->product_ref) . '</ram:SellerAssignedID>' . "\n";
		}
		$xml .= '        <ram:Name>' . $this->xmlEncode($line->product_label ?: $line->desc) . '</ram:Name>' . "\n";
		if (!empty($line->desc) && $line->desc != $line->product_label) {
			$xml .= '        <ram:Description>' . $this->xmlEncode(strip_tags($line->desc)) . '</ram:Description>' . "\n";
		}
		$xml .= '      </ram:SpecifiedTradeProduct>' . "\n";

		// Line agreement (price)
		$xml .= '      <ram:SpecifiedLineTradeAgreement>' . "\n";
		$xml .= '        <ram:NetPriceProductTradePrice>' . "\n";
		$xml .= '          <ram:ChargeAmount>' . $this->formatAmount($line->subprice) . '</ram:ChargeAmount>' . "\n";
		$xml .= '        </ram:NetPriceProductTradePrice>' . "\n";
		$xml .= '      </ram:SpecifiedLineTradeAgreement>' . "\n";

		// Line delivery (quantity)
		$xml .= '      <ram:SpecifiedLineTradeDelivery>' . "\n";
		$xml .= '        <ram:BilledQuantity unitCode="' . $this->getUnitCode($line) . '">' . $this->formatQuantity($line->qty) . '</ram:BilledQuantity>' . "\n";
		$xml .= '      </ram:SpecifiedLineTradeDelivery>' . "\n";

		// Line settlement (tax, total)
		$xml .= '      <ram:SpecifiedLineTradeSettlement>' . "\n";
		$xml .= '        <ram:ApplicableTradeTax>' . "\n";
		$xml .= '          <ram:TypeCode>VAT</ram:TypeCode>' . "\n";
		$xml .= '          <ram:CategoryCode>' . $this->getVATCategoryCode($line->tva_tx) . '</ram:CategoryCode>' . "\n";
		$xml .= '          <ram:RateApplicablePercent>' . $this->formatAmount($line->tva_tx) . '</ram:RateApplicablePercent>' . "\n";
		$xml .= '        </ram:ApplicableTradeTax>' . "\n";
		$xml .= '        <ram:SpecifiedTradeSettlementLineMonetarySummation>' . "\n";
		$xml .= '          <ram:LineTotalAmount>' . $this->formatAmount($line->total_ht) . '</ram:LineTotalAmount>' . "\n";
		$xml .= '        </ram:SpecifiedTradeSettlementLineMonetarySummation>' . "\n";
		$xml .= '      </ram:SpecifiedLineTradeSettlement>' . "\n";

		$xml .= '    </ram:IncludedSupplyChainTradeLineItem>' . "\n";

		return $xml;
	}

	/**
	 * Create ApplicableHeaderTradeAgreement element (seller/buyer)
	 *
	 * @param Facture $invoice Invoice object
	 * @param Societe $mysoc   Seller company
	 * @return string XML content
	 */
	private function createApplicableHeaderTradeAgreement($invoice, $mysoc)
	{
		$buyer = $invoice->thirdparty;

		// Load extrafields for buyer if not loaded
		if (empty($buyer->array_options)) {
			$buyer->fetch_optionals();
		}

		$xml = '    <ram:ApplicableHeaderTradeAgreement>' . "\n";

		// Buyer Reference (Leitweg-ID for XRechnung) - must come before SellerTradeParty
		$leitwegId = '';
		if (!empty($buyer->array_options['options_leitweg_id'])) {
			$leitwegId = $buyer->array_options['options_leitweg_id'];
		}
		if (!empty($leitwegId)) {
			$xml .= '      <ram:BuyerReference>' . $this->xmlEncode($leitwegId) . '</ram:BuyerReference>' . "\n";
		}

		// Seller
		$xml .= '      <ram:SellerTradeParty>' . "\n";
		$xml .= '        <ram:Name>' . $this->xmlEncode($mysoc->name) . '</ram:Name>' . "\n";

		// Seller address
		$xml .= '        <ram:PostalTradeAddress>' . "\n";
		$xml .= '          <ram:PostcodeCode>' . $this->xmlEncode($mysoc->zip) . '</ram:PostcodeCode>' . "\n";
		$xml .= '          <ram:LineOne>' . $this->xmlEncode($mysoc->address) . '</ram:LineOne>' . "\n";
		$xml .= '          <ram:CityName>' . $this->xmlEncode($mysoc->town) . '</ram:CityName>' . "\n";
		$xml .= '          <ram:CountryID>' . $this->xmlEncode($mysoc->country_code) . '</ram:CountryID>' . "\n";
		$xml .= '        </ram:PostalTradeAddress>' . "\n";

		// Seller tax registration
		if (!empty($mysoc->tva_intra)) {
			$xml .= '        <ram:SpecifiedTaxRegistration>' . "\n";
			$xml .= '          <ram:ID schemeID="VA">' . $this->xmlEncode($mysoc->tva_intra) . '</ram:ID>' . "\n";
			$xml .= '        </ram:SpecifiedTaxRegistration>' . "\n";
		}

		$xml .= '      </ram:SellerTradeParty>' . "\n";

		// Buyer
		$xml .= '      <ram:BuyerTradeParty>' . "\n";
		$xml .= '        <ram:Name>' . $this->xmlEncode($buyer->name) . '</ram:Name>' . "\n";

		// Buyer address
		$xml .= '        <ram:PostalTradeAddress>' . "\n";
		$xml .= '          <ram:PostcodeCode>' . $this->xmlEncode($buyer->zip) . '</ram:PostcodeCode>' . "\n";
		$xml .= '          <ram:LineOne>' . $this->xmlEncode($buyer->address) . '</ram:LineOne>' . "\n";
		$xml .= '          <ram:CityName>' . $this->xmlEncode($buyer->town) . '</ram:CityName>' . "\n";
		$xml .= '          <ram:CountryID>' . $this->xmlEncode($buyer->country_code) . '</ram:CountryID>' . "\n";
		$xml .= '        </ram:PostalTradeAddress>' . "\n";

		// Buyer tax registration
		if (!empty($buyer->tva_intra)) {
			$xml .= '        <ram:SpecifiedTaxRegistration>' . "\n";
			$xml .= '          <ram:ID schemeID="VA">' . $this->xmlEncode($buyer->tva_intra) . '</ram:ID>' . "\n";
			$xml .= '        </ram:SpecifiedTaxRegistration>' . "\n";
		}

		$xml .= '      </ram:BuyerTradeParty>' . "\n";

		// Buyer order reference
		if (!empty($invoice->ref_client)) {
			$xml .= '      <ram:BuyerOrderReferencedDocument>' . "\n";
			$xml .= '        <ram:IssuerAssignedID>' . $this->xmlEncode($invoice->ref_client) . '</ram:IssuerAssignedID>' . "\n";
			$xml .= '      </ram:BuyerOrderReferencedDocument>' . "\n";
		}

		$xml .= '    </ram:ApplicableHeaderTradeAgreement>' . "\n";

		return $xml;
	}

	/**
	 * Create ApplicableHeaderTradeDelivery element
	 *
	 * @param Facture $invoice Invoice object
	 * @return string XML content
	 */
	private function createApplicableHeaderTradeDelivery($invoice)
	{
		$xml = '    <ram:ApplicableHeaderTradeDelivery>' . "\n";

		// Ship to party (same as buyer for now)
		$buyer = $invoice->thirdparty;
		$xml .= '      <ram:ShipToTradeParty>' . "\n";
		$xml .= '        <ram:Name>' . $this->xmlEncode($buyer->name) . '</ram:Name>' . "\n";
		$xml .= '        <ram:PostalTradeAddress>' . "\n";
		$xml .= '          <ram:PostcodeCode>' . $this->xmlEncode($buyer->zip) . '</ram:PostcodeCode>' . "\n";
		$xml .= '          <ram:LineOne>' . $this->xmlEncode($buyer->address) . '</ram:LineOne>' . "\n";
		$xml .= '          <ram:CityName>' . $this->xmlEncode($buyer->town) . '</ram:CityName>' . "\n";
		$xml .= '          <ram:CountryID>' . $this->xmlEncode($buyer->country_code) . '</ram:CountryID>' . "\n";
		$xml .= '        </ram:PostalTradeAddress>' . "\n";
		$xml .= '      </ram:ShipToTradeParty>' . "\n";

		$xml .= '    </ram:ApplicableHeaderTradeDelivery>' . "\n";

		return $xml;
	}

	/**
	 * Create ApplicableHeaderTradeSettlement element (payment, totals)
	 *
	 * @param Facture $invoice Invoice object
	 * @return string XML content
	 */
	private function createApplicableHeaderTradeSettlement($invoice)
	{
		global $conf;

		$xml = '    <ram:ApplicableHeaderTradeSettlement>' . "\n";

		// Currency
		$xml .= '      <ram:InvoiceCurrencyCode>' . ($invoice->multicurrency_code ?: $conf->currency) . '</ram:InvoiceCurrencyCode>' . "\n";

		// Get bank account IBAN from invoice
		$iban = '';
		$bic = '';
		$bankName = '';
		if (!empty($invoice->fk_account)) {
			require_once DOL_DOCUMENT_ROOT . '/compta/bank/class/account.class.php';
			$bankAccount = new Account($this->db);
			if ($bankAccount->fetch($invoice->fk_account) > 0) {
				$iban = $bankAccount->iban;
				$bic = $bankAccount->bic;
				$bankName = $bankAccount->bank;
			}
		}

		// Payment means
		$xml .= '      <ram:SpecifiedTradeSettlementPaymentMeans>' . "\n";
		$xml .= '        <ram:TypeCode>' . $this->getPaymentMeansCode($invoice) . '</ram:TypeCode>' . "\n";

		// Bank account for SEPA transfer
		if (!empty($iban)) {
			$xml .= '        <ram:PayeePartyCreditorFinancialAccount>' . "\n";
			$xml .= '          <ram:IBANID>' . $this->xmlEncode($iban) . '</ram:IBANID>' . "\n";
			$xml .= '        </ram:PayeePartyCreditorFinancialAccount>' . "\n";

			// BIC if available
			if (!empty($bic)) {
				$xml .= '        <ram:PayeeSpecifiedCreditorFinancialInstitution>' . "\n";
				$xml .= '          <ram:BICID>' . $this->xmlEncode($bic) . '</ram:BICID>' . "\n";
				if (!empty($bankName)) {
					$xml .= '          <ram:Name>' . $this->xmlEncode($bankName) . '</ram:Name>' . "\n";
				}
				$xml .= '        </ram:PayeeSpecifiedCreditorFinancialInstitution>' . "\n";
			}
		}

		$xml .= '      </ram:SpecifiedTradeSettlementPaymentMeans>' . "\n";

		// Tax summary
		$xml .= $this->createTaxSummary($invoice);

		// Payment terms
		if (!empty($invoice->cond_reglement_id)) {
			$xml .= '      <ram:SpecifiedTradePaymentTerms>' . "\n";
			if ($invoice->date_lim_reglement) {
				$xml .= '        <ram:DueDateDateTime>' . "\n";
				$xml .= '          <udt:DateTimeString format="102">' . date('Ymd', $invoice->date_lim_reglement) . '</udt:DateTimeString>' . "\n";
				$xml .= '        </ram:DueDateDateTime>' . "\n";
			}
			$xml .= '      </ram:SpecifiedTradePaymentTerms>' . "\n";
		}

		// Monetary summation
		$xml .= '      <ram:SpecifiedTradeSettlementHeaderMonetarySummation>' . "\n";
		$xml .= '        <ram:LineTotalAmount>' . $this->formatAmount($invoice->total_ht) . '</ram:LineTotalAmount>' . "\n";
		$xml .= '        <ram:TaxBasisTotalAmount>' . $this->formatAmount($invoice->total_ht) . '</ram:TaxBasisTotalAmount>' . "\n";
		$xml .= '        <ram:TaxTotalAmount currencyID="' . ($invoice->multicurrency_code ?: $conf->currency) . '">' . $this->formatAmount($invoice->total_tva) . '</ram:TaxTotalAmount>' . "\n";
		$xml .= '        <ram:GrandTotalAmount>' . $this->formatAmount($invoice->total_ttc) . '</ram:GrandTotalAmount>' . "\n";
		$xml .= '        <ram:DuePayableAmount>' . $this->formatAmount($invoice->total_ttc - $invoice->getSommePaiement()) . '</ram:DuePayableAmount>' . "\n";
		$xml .= '      </ram:SpecifiedTradeSettlementHeaderMonetarySummation>' . "\n";

		$xml .= '    </ram:ApplicableHeaderTradeSettlement>' . "\n";

		return $xml;
	}

	/**
	 * Check if a line should be skipped (title, subtotal, etc.)
	 *
	 * @param FactureLigne $line Invoice line
	 * @return bool True if line should be skipped
	 */
	private function isSkippableLine($line)
	{
		// Skip free text lines (product_type == 9 in some modules)
		if (isset($line->product_type) && $line->product_type == 9) {
			return true;
		}

		// Skip lines with special_code for titles/subtotals (subtotaltitle module uses special_code)
		if (!empty($line->special_code) && in_array($line->special_code, array(104777, 104778, 104779))) {
			return true;
		}

		// Skip lines where qty is 0 and total is 0 and it looks like a title/subtotal
		if ((float) $line->qty == 0 && (float) $line->total_ht == 0 && (float) $line->subprice == 0) {
			return true;
		}

		// Skip lines where description contains "Zwischensumme" or starts with title markers
		$desc = strtolower($line->desc ?? '');
		if (strpos($desc, 'zwischensumme') !== false) {
			return true;
		}

		return false;
	}

	/**
	 * Create tax summary from invoice lines
	 *
	 * @param Facture $invoice Invoice object
	 * @return string XML content
	 */
	private function createTaxSummary($invoice)
	{
		// Group by VAT rate - only include real lines
		$vatGroups = array();
		foreach ($invoice->lines as $line) {
			// Skip title/subtotal lines
			if ($this->isSkippableLine($line)) {
				continue;
			}
			$rate = (float) $line->tva_tx;
			if (!isset($vatGroups[$rate])) {
				$vatGroups[$rate] = array(
					'base' => 0,
					'amount' => 0,
				);
			}
			$vatGroups[$rate]['base'] += $line->total_ht;
			$vatGroups[$rate]['amount'] += $line->total_tva;
		}

		$xml = '';
		foreach ($vatGroups as $rate => $data) {
			$xml .= '      <ram:ApplicableTradeTax>' . "\n";
			$xml .= '        <ram:CalculatedAmount>' . $this->formatAmount($data['amount']) . '</ram:CalculatedAmount>' . "\n";
			$xml .= '        <ram:TypeCode>VAT</ram:TypeCode>' . "\n";
			$xml .= '        <ram:BasisAmount>' . $this->formatAmount($data['base']) . '</ram:BasisAmount>' . "\n";
			$xml .= '        <ram:CategoryCode>' . $this->getVATCategoryCode($rate) . '</ram:CategoryCode>' . "\n";
			$xml .= '        <ram:RateApplicablePercent>' . $this->formatAmount($rate) . '</ram:RateApplicablePercent>' . "\n";
			$xml .= '      </ram:ApplicableTradeTax>' . "\n";
		}

		return $xml;
	}

	/**
	 * Get payment means code (UNCL 4461)
	 *
	 * @param Facture $invoice Invoice object
	 * @return string Payment means code
	 */
	private function getPaymentMeansCode($invoice)
	{
		// 10 = Cash
		// 30 = Credit transfer
		// 42 = Payment to bank account
		// 48 = Bank card
		// 49 = Direct debit
		// 58 = SEPA credit transfer
		// 59 = SEPA direct debit
		return '58'; // Default to SEPA credit transfer
	}

	/**
	 * Get VAT category code (UNCL 5305)
	 *
	 * @param float $rate VAT rate
	 * @return string Category code
	 */
	private function getVATCategoryCode($rate)
	{
		// S = Standard rate
		// Z = Zero rated
		// E = Exempt
		// AE = Reverse charge
		// K = Intra-community supply
		// G = Export outside EU
		// O = Outside scope of VAT
		// L = Canary Islands
		// M = Ceuta and Melilla
		if ($rate == 0) {
			return 'Z';
		}
		return 'S';
	}

	/**
	 * Get unit code (UN/ECE Rec. 20)
	 *
	 * @param FactureLigne $line Invoice line
	 * @return string Unit code
	 */
	private function getUnitCode($line)
	{
		// Map Dolibarr units to UN/ECE codes
		// Common codes: C62=piece, HUR=hour, DAY=day, MTR=meter, KGM=kilogram, LTR=liter
		$unit = strtolower($line->product_type == 1 ? 'service' : ($line->fk_unit ?: 'piece'));

		$unitMap = array(
			'piece' => 'C62',
			'pce' => 'C62',
			'stk' => 'C62',
			'stück' => 'C62',
			'hour' => 'HUR',
			'h' => 'HUR',
			'std' => 'HUR',
			'stunde' => 'HUR',
			'day' => 'DAY',
			'tag' => 'DAY',
			'meter' => 'MTR',
			'm' => 'MTR',
			'kg' => 'KGM',
			'kilogram' => 'KGM',
			'liter' => 'LTR',
			'l' => 'LTR',
			'service' => 'C62',
		);

		return $unitMap[$unit] ?? 'C62';
	}

	/**
	 * Format amount for XML
	 *
	 * @param float $amount Amount
	 * @return string Formatted amount
	 */
	private function formatAmount($amount)
	{
		return number_format((float) $amount, 2, '.', '');
	}

	/**
	 * Format quantity for XML
	 *
	 * @param float $qty Quantity
	 * @return string Formatted quantity
	 */
	private function formatQuantity($qty)
	{
		return number_format((float) $qty, 4, '.', '');
	}

	/**
	 * Encode string for XML
	 *
	 * @param string $string String to encode
	 * @return string Encoded string
	 */
	private function xmlEncode($string)
	{
		return htmlspecialchars((string) $string, ENT_XML1 | ENT_QUOTES, 'UTF-8');
	}

	/**
	 * Set profile
	 *
	 * @param string $profile Profile constant
	 * @return void
	 */
	public function setProfile($profile)
	{
		$this->profile = $profile;
	}

	/**
	 * Get generated XML filename
	 *
	 * @param Facture $invoice Invoice object
	 * @return string Filename
	 */
	public function getXMLFilename($invoice)
	{
		if ($this->profile === self::PROFILE_XRECHNUNG) {
			return 'xrechnung-' . $invoice->ref . '.xml';
		}
		return 'factur-x.xml';
	}

	/**
	 * Save XML to file
	 *
	 * @param Facture $invoice Invoice object
	 * @param string  $xml     XML content
	 * @return string|false File path or false on error
	 */
	public function saveXML($invoice, $xml)
	{
		global $conf;

		$dir = $conf->facture->dir_output . '/' . dol_sanitizeFileName($invoice->ref);

		if (!is_dir($dir)) {
			dol_mkdir($dir);
		}

		$filename = $this->getXMLFilename($invoice);
		$filepath = $dir . '/' . $filename;

		$result = file_put_contents($filepath, $xml);

		if ($result === false) {
			$this->error = 'Failed to write XML file: ' . $filepath;
			return false;
		}

		return $filepath;
	}
}