<?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/pdfembedder.class.php
 * \ingroup exportzugferd
 * \brief   Embeds ZUGFeRD/Factur-X XML into PDF
 */

/**
 * Class ZugferdPdfEmbedder
 * Embeds ZUGFeRD XML into existing PDF files to create PDF/A-3 compliant ZUGFeRD PDFs
 */
class ZugferdPdfEmbedder
{
	/**
	 * @var string Last error message
	 */
	public $error = '';

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

	/**
	 * Embed XML file into existing PDF
	 *
	 * @param string $pdfFile    Path to the PDF file
	 * @param string $xmlFile    Path to the XML file to embed
	 * @param string $profile    ZUGFeRD profile (MINIMUM, BASIC, EN16931, XRECHNUNG, EXTENDED)
	 * @return bool True on success, false on error
	 */
	public function embedXmlInPdf($pdfFile, $xmlFile, $profile = 'EN16931')
	{
		global $conf;

		dol_syslog("ZugferdPdfEmbedder::embedXmlInPdf called - PDF: $pdfFile, XML: $xmlFile", LOG_INFO);

		if (!file_exists($pdfFile)) {
			$this->error = 'PDF file not found: ' . $pdfFile;
			dol_syslog("ZugferdPdfEmbedder: " . $this->error, LOG_ERR);
			return false;
		}

		if (!file_exists($xmlFile)) {
			$this->error = 'XML file not found: ' . $xmlFile;
			dol_syslog("ZugferdPdfEmbedder: " . $this->error, LOG_ERR);
			return false;
		}

		// Load TCPDF first (required by TCPDI)
		if (!class_exists('TCPDF')) {
			$tcpdfPath = DOL_DOCUMENT_ROOT . '/includes/tecnickcom/tcpdf/tcpdf.php';
			if (file_exists($tcpdfPath)) {
				require_once $tcpdfPath;
			} else {
				$this->error = 'TCPDF library not found';
				dol_syslog("ZugferdPdfEmbedder: " . $this->error, LOG_ERR);
				return false;
			}
		}

		// Check if TCPDI is available
		if (!class_exists('TCPDI')) {
			$tcpdiPath = DOL_DOCUMENT_ROOT . '/includes/tcpdi/tcpdi.php';
			if (file_exists($tcpdiPath)) {
				require_once $tcpdiPath;
			} else {
				$this->error = 'TCPDI library not found';
				dol_syslog("ZugferdPdfEmbedder: " . $this->error, LOG_ERR);
				return false;
			}
		}

		try {
			// Read XML content
			$xmlContent = file_get_contents($xmlFile);
			if ($xmlContent === false) {
				$this->error = 'Could not read XML file';
				dol_syslog("ZugferdPdfEmbedder: " . $this->error, LOG_ERR);
				return false;
			}

			dol_syslog("ZugferdPdfEmbedder: Creating TCPDI object", LOG_DEBUG);

			// Create new PDF with embedded XML
			$pdf = new TCPDI('P', 'mm', 'A4', true, 'UTF-8');
			dol_syslog("ZugferdPdfEmbedder: TCPDI object created", LOG_DEBUG);

			// Disable header and footer
			$pdf->setPrintHeader(false);
			$pdf->setPrintFooter(false);

			// Set PDF/A-3 mode for ZUGFeRD compliance (only if method exists - TCPDI may not have it)
			if (method_exists($pdf, 'setPDFA')) {
				$pdf->setPDFA(true);
			}

			// Set document information
			$pdf->SetCreator('Dolibarr ExportZugferd');
			$pdf->SetAuthor('Dolibarr ERP/CRM');
			$pdf->SetTitle('ZUGFeRD Invoice');
			$pdf->SetSubject('Electronic Invoice with embedded ZUGFeRD XML');

			dol_syslog("ZugferdPdfEmbedder: Setting source file: $pdfFile", LOG_DEBUG);

			// Import existing PDF pages
			$pageCount = $pdf->setSourceFile($pdfFile);
			dol_syslog("ZugferdPdfEmbedder: Importing $pageCount pages", LOG_DEBUG);

			for ($pageNo = 1; $pageNo <= $pageCount; $pageNo++) {
				dol_syslog("ZugferdPdfEmbedder: Importing page $pageNo", LOG_DEBUG);
				$templateId = $pdf->importPage($pageNo);
				$size = $pdf->getTemplateSize($templateId);

				// TCPDI returns 'w' and 'h' keys, not 'width' and 'height'
				$width = isset($size['w']) ? $size['w'] : (isset($size['width']) ? $size['width'] : 210);
				$height = isset($size['h']) ? $size['h'] : (isset($size['height']) ? $size['height'] : 297);
				$orientation = isset($size['orientation']) ? $size['orientation'] : ($width > $height ? 'L' : 'P');

				dol_syslog("ZugferdPdfEmbedder: Page $pageNo size: {$width}x{$height}, orientation: $orientation", LOG_DEBUG);

				// Add page with same size as original
				$pdf->AddPage($orientation, array($width, $height));
				$pdf->useTemplate($templateId);
			}

			dol_syslog("ZugferdPdfEmbedder: All pages imported", LOG_DEBUG);

			// Determine the attachment filename based on profile
			$attachmentName = $this->getAttachmentFilename($profile);

			dol_syslog("ZugferdPdfEmbedder: Adding embedded file for $attachmentName", LOG_DEBUG);

			// Embed XML using the correct ZUGFeRD method: only in EmbeddedFiles name tree
			// NOT as a FileAttachment annotation (which causes double listing)
			$this->addEmbeddedFile($pdf, $xmlFile, $attachmentName);

			dol_syslog("ZugferdPdfEmbedder: Embedded file added", LOG_DEBUG);

			// Create temporary file for output
			$tempFile = $pdfFile . '.tmp';

			// Output the modified PDF
			$pdf->Output($tempFile, 'F');

			dol_syslog("ZugferdPdfEmbedder: Temp file created: $tempFile", LOG_DEBUG);

			// Replace original with modified version
			if (file_exists($tempFile)) {
				if (filesize($tempFile) > 0) {
					// Replace original
					if (!rename($tempFile, $pdfFile)) {
						$this->error = 'Could not replace original PDF file';
						@unlink($tempFile);
						dol_syslog("ZugferdPdfEmbedder: " . $this->error, LOG_ERR);
						return false;
					}

					dol_syslog("ZugferdPdfEmbedder: Successfully embedded XML into PDF: " . $pdfFile, LOG_INFO);
					return true;
				} else {
					$this->error = 'Generated PDF is empty';
					@unlink($tempFile);
					dol_syslog("ZugferdPdfEmbedder: " . $this->error, LOG_ERR);
					return false;
				}
			} else {
				$this->error = 'Failed to create temporary PDF file';
				dol_syslog("ZugferdPdfEmbedder: " . $this->error, LOG_ERR);
				return false;
			}

		} catch (Exception $e) {
			$this->error = 'PDF embedding failed: ' . $e->getMessage();
			dol_syslog("ZugferdPdfEmbedder error: " . $e->getMessage(), LOG_ERR);
			return false;
		}
	}

	/**
	 * Get the standard attachment filename for the profile
	 *
	 * @param string $profile ZUGFeRD profile
	 * @return string Filename
	 */
	private function getAttachmentFilename($profile)
	{
		switch (strtoupper($profile)) {
			case 'XRECHNUNG':
				return 'xrechnung.xml';
			case 'MINIMUM':
			case 'BASIC':
			case 'BASIC WL':
			case 'EN16931':
			case 'EXTENDED':
			default:
				return 'factur-x.xml';
		}
	}

	/**
	 * Embed XML content directly into PDF (alternative method)
	 *
	 * @param string $pdfFile     Path to the PDF file
	 * @param string $xmlContent  XML content to embed
	 * @param string $xmlFilename Filename for the embedded XML (e.g., factur-x.xml)
	 * @param string $profile     ZUGFeRD profile
	 * @return bool True on success, false on error
	 */
	public function embedXmlContentInPdf($pdfFile, $xmlContent, $xmlFilename = 'factur-x.xml', $profile = 'EN16931')
	{
		// Create temporary XML file
		$tempXmlFile = sys_get_temp_dir() . '/' . $xmlFilename;

		if (file_put_contents($tempXmlFile, $xmlContent) === false) {
			$this->error = 'Could not create temporary XML file';
			return false;
		}

		$result = $this->embedXmlInPdf($pdfFile, $tempXmlFile, $profile);

		// Clean up temporary file
		@unlink($tempXmlFile);

		return $result;
	}

	/**
	 * Check if embedding is possible
	 *
	 * @return bool True if libraries are available
	 */
	public static function isEmbeddingAvailable()
	{
		// Check for TCPDF
		$tcpdfAvailable = class_exists('TCPDF') || file_exists(DOL_DOCUMENT_ROOT . '/includes/tecnickcom/tcpdf/tcpdf.php');

		// Check for TCPDI
		$tcpdiAvailable = class_exists('TCPDI') || file_exists(DOL_DOCUMENT_ROOT . '/includes/tcpdi/tcpdi.php');

		return $tcpdfAvailable && $tcpdiAvailable;
	}

	/**
	 * Get ZUGFeRD conformance level string for XMP metadata
	 *
	 * @param string $profile Profile name
	 * @return string Conformance level
	 */
	private function getConformanceLevel($profile)
	{
		switch (strtoupper($profile)) {
			case 'MINIMUM':
				return 'MINIMUM';
			case 'BASIC WL':
			case 'BASICWL':
				return 'BASIC WL';
			case 'BASIC':
				return 'BASIC';
			case 'EN16931':
				return 'EN 16931';
			case 'EXTENDED':
				return 'EXTENDED';
			case 'XRECHNUNG':
				return 'EN 16931';
			default:
				return 'EN 16931';
		}
	}

	/**
	 * Add embedded file to PDF without creating a FileAttachment annotation
	 * This ensures the file is only listed once in the EmbeddedFiles name tree
	 *
	 * @param TCPDI  $pdf      PDF object
	 * @param string $filepath Path to the file to embed
	 * @param string $filename Name for the embedded file
	 * @return void
	 */
	private function addEmbeddedFile($pdf, $filepath, $filename)
	{
		// Access TCPDF's internal embeddedfiles array directly
		// This avoids creating a FileAttachment annotation which causes double listing
		$reflection = new ReflectionClass($pdf);

		// Get the 'n' property (object counter)
		$nProp = $reflection->getProperty('n');
		$nProp->setAccessible(true);
		$n = $nProp->getValue($pdf);

		// Get the embeddedfiles array
		$efProp = $reflection->getProperty('embeddedfiles');
		$efProp->setAccessible(true);
		$embeddedfiles = $efProp->getValue($pdf);

		// Add the file to the embeddedfiles array
		$embeddedfiles[$filename] = array(
			'f' => ++$n,
			'n' => ++$n,
			'file' => $filepath
		);

		// Update the object counter
		$nProp->setValue($pdf, $n);

		// Update the embeddedfiles array
		$efProp->setValue($pdf, $embeddedfiles);

		dol_syslog("ZugferdPdfEmbedder: Added $filename to embeddedfiles array", LOG_DEBUG);
	}
}