<?php

AlphaAutoLoader::loadLib('eng.php');

/**
 *
 * A facade class for the TCPDF library which is used to convert some HTML content provided by the
 * Markdown library to a PDF file using FPDF
 * 
 * @package alpha::util
 * @since 1.0
 * @author John Collins <dev@alphaframework.org>
 * @version $Id: TCPDFFacade.inc 1550 2012-07-29 21:15:40Z alphadevx $
 * @license http://www.opensource.org/licenses/bsd-license.php The BSD License
 * @copyright Copyright (c) 2012, John Collins (founder of Alpha Framework).  
 * All rights reserved.
 * 
 * <pre>
 * Redistribution and use in source and binary forms, with or 
 * without modification, are permitted provided that the 
 * following conditions are met:
 * 
 * * Redistributions of source code must retain the above 
 *   copyright notice, this list of conditions and the 
 *   following disclaimer.
 * * Redistributions in binary form must reproduce the above 
 *   copyright notice, this list of conditions and the 
 *   following disclaimer in the documentation and/or other 
 *   materials provided with the distribution.
 * * Neither the name of the Alpha Framework nor the names 
 *   of its contributors may be used to endorse or promote 
 *   products derived from this software without specific 
 *   prior written permission.
 *   
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 
 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, 
 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR 
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE 
 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * </pre>
 *  
 */ 
class TCPDFFacade {
	/**
	 * The HTML-format content that we will render as a PDF
	 * 
	 * @var string
	 * @since 1.0
	 */	
	private $content;
	
	/**
	 * The PDF object that will be generated from the Markdown HTML content
	 * 
	 * @var AlphaTCPDF
	 * @since 1.0
	 */
	private $pdf;
	
	/**
	 * The business object that stores the content will be rendered to Markdown
	 * 
	 * @var AlphaDAO
	 * @since 1.0
	 */
	private $BO = null;
	
	/**
	 * The auto-generated name of the PDF cache file for the BO
	 * 
	 * @var string
	 * @since 1.0
	 */
	private $PDFFilename;
	
	/**
	 * The auto-generated name of the HTML cache file for the BO generated by Markdown
	 * 
	 * @var string
	 * @since 1.0
	 */
	private $HTMLFilename;
	
	/**
	 * The constructor
	 * 
	 * @param object $BO the business object that stores the content will be rendered to Markdown
	 * @since 1.0
	 */
	public function __construct($BO) {
		global $config;
		global $l;
		
		$this->BO = $BO;
		$this->PDFFilename = $config->get('app.file.store.dir').'cache/pdf/'.get_class($this->BO).'_'.$this->BO->getID().'_'.$this->BO->getVersion().'.pdf';
		$PDFDownloadName = str_replace(' ', '_', $this->BO->get('title').'.pdf');
		$this->HTMLFilename = $config->get('app.file.store.dir').'cache/html/'.get_class($this->BO).'_'.$this->BO->getID().'_'.$this->BO->getVersion().'.html';
		
		// first check the PDF cache, and if its there then re-direct to the file
		if($this->checkPDFCache())
			$this->serveCachedPDF($PDFDownloadName);
		
		if(method_exists($this->BO, 'getAttachmentsURL'))
			$attachURL = $this->BO->getAttachmentsURL();
		else
			$attachURL = '';
		
		if ($this->checkHTMLCache()) {
			$this->loadHTMLCache();
		}else{
			$this->content = $this->markdown($this->BO->get('content', true), $attachURL);
			$this->HTMLCache();
		}
		
		// Replace all instances of $attachURL in link tags to links to the ViewAttachment controller
		$attachments = array();		
		preg_match_all('/href\=\"\$attachURL\/.*\"/', $this->content, $attachments);
		
		foreach($attachments[0] as $attachmentURL) {
			$start = strpos($attachmentURL, '/');
			$end = strrpos($attachmentURL, '"');
			$fileName = substr($attachmentURL, $start+1, $end-($start+1));

			if(method_exists($this->BO, 'getAttachmentSecureURL')) {
				$this->content = str_replace($attachmentURL, 'href='.$this->BO->getAttachmentSecureURL($fileName), $this->content);
			}
		}
		
		// Handle image attachments		
		$attachments = array();		
		preg_match_all('/\<img\ src\=\"\$attachURL\/.*\".*\>/', $this->content, $attachments);
			
		foreach($attachments[0] as $attachmentURL) {
			$start = strpos($attachmentURL, '/');
			$end = strrpos($attachmentURL, '" alt');
			$fileName = substr($attachmentURL, $start+1, $end-($start+1));
	
			if($config->get('cms.images.widget')) {
				// get the details of the source image
				$path = $this->BO->getAttachmentsLocation().'/'.$fileName;
				$image_details = getimagesize($path);
				$imgType = $image_details[2];
		    	if($imgType == 1)
		    		$type = 'gif';
		    	elseif($imgType == 2)
		    		$type = 'jpg';
		    	elseif($imgType == 3)
		    		$type = 'png';
		    		
				$img = new Image($path, $image_details[0], $image_details[1], $type, 0.95, false, (boolean)$config->get('cms.images.widget.secure'));
				$this->content = str_replace($attachmentURL, $img->renderHTMLLink(), $this->content);
			}else{
				// render a normal image link to the ViewAttachment controller				
				if(method_exists($this->BO, 'getAttachmentSecureURL')) {
					$this->content = str_replace($attachmentURL, '<img src="'.$this->BO->getAttachmentSecureURL($fileName).'">', $this->content);
				}
			}
		}
		
		$this->pdf = new AlphaTCPDF(PDF_PAGE_ORIENTATION, PDF_UNIT, PDF_PAGE_FORMAT, true, 'UTF-8', false);
		$this->pdf->SetCreator(PDF_CREATOR);
		$this->pdf->SetAuthor($this->BO->get('author'));
		$this->pdf->SetTitle($this->BO->get('title'));
		$this->pdf->SetSubject($this->BO->get('description'));
		// TODO inject tags here?
		//$this->pdf->SetKeywords($this->BO->get('keywords'));
		
		//set margins
		$this->pdf->SetMargins(PDF_MARGIN_LEFT, PDF_MARGIN_TOP, PDF_MARGIN_RIGHT);
		$this->pdf->SetHeaderMargin(PDF_MARGIN_HEADER);
		$this->pdf->SetFooterMargin(PDF_MARGIN_FOOTER);
		
		//set auto page breaks
		$this->pdf->SetAutoPageBreak(TRUE, PDF_MARGIN_BOTTOM);
		
		//set image scale factor
		$this->pdf->setImageScale(2.5); 
		
		//set some language-dependent strings
		$this->pdf->setLanguageArray($l);
		
		// add a page
		$this->pdf->AddPage();
		
		// add the title
		$title = '<h1>'.$this->BO->get('title').'</h1>';
		// add some custom footer info about the article		
		$footer = '<br><p>Article URL: <a href="'.$this->BO->get('URL').'">'.$this->BO->get('URL').'</a><br>Title: '.$this->BO->get('title').'<br>Author: '.$this->BO->get('author').'</p>';
		
		// write the title
		$this->pdf->writeHTML($title, true, 0, true, 0);
		// output the HTML content
		$this->pdf->writeHTML($this->content, true, 0, true, 0);
		// write the article footer
		$this->pdf->writeHTML($footer, true, 0, true, 0);		
		
		// save this PDF to the cache
		$this->pdf->Output($this->PDFFilename, 'F');		
		$this->serveCachedPDF($PDFDownloadName);
	}
	
	/**
	 * Facade method which will invoke our custom markdown class rather than the standard one
	 * 
	 * @since 1.0
	 */
	 private function markdown($text, $attachURL='') {
	 	global $config;
	 	
		/*
		 * Initialize the parser and return the result of its transform method.
		 * 
		 */		
		static $parser;
		if (!isset($parser)) {
			$parser_class = 'AlphaMarkdown';
			$parser = new $parser_class;
		}
		
		/*
		 * Replace all instances of $sysURL in the text with the app.url setting from config
		 * 
		 */
		$text = str_replace('$sysURL', $config->get('app.url'), $text);
		
		// transform text using parser.
		return $parser->transform($text);
	}
	
	/**
	 * Fetter for the content
	 * 
	 * @return string HTML rendered the content
	 * @since 1.0
	 */
	public function getContent() {
		return $this->content;
	}
	
	/**
	 * Saves the HTML generated by Markdown to the cache directory
	 * 
	 * @since 1.0	 
	 */
	private function HTMLCache() {
		// check to ensure that the article is not transient before caching it
		if ($this->BO->getID() != '00000000000') {
			$fp=fopen($this->HTMLFilename,"w");
			if (!$fp) {
				throw new AlphaException('Failed to open the cache file for writing, directory permissions my not be set correctly!');
			}else{
				flock($fp,2); // locks the file for writting		    
				fwrite($fp,$this->content); 
				flock($fp,3); // unlocks the file
				fclose($fp); //closes the file
			}
		}
	}
	
	/**
	 * Used to check the HTML cache for the BO cache file
	 * 	 
	 * @return bool true if the file exists, false otherwise
	 * @since 1.0
	 */
	private function checkHTMLCache() {
		global $config;
		
		return file_exists($this->HTMLFilename);
	}
	
	/**
	 * Method to load the content of the cache file to the $content attribute of this object
	 * 
	 * @since 1.0	 
	 */
	private function loadHTMLCache() {		
		$fp = fopen($this->HTMLFilename,"r");
		
		if (!$fp) {
			throw new AlphaException('Failed to open the cache file for reading, directory permissions my not be set correctly!' ,'loadHTMLCache()');
		}else{				    
			$this->content = fread($fp, filesize($this->HTMLFilename));			
			fclose($fp); //closes the file			
		}
	}
	
	/**
	 * Used to check the PDF cache for the BO cache file
	 * 	 
	 * @return bool true if the file exists, false otherwise
	 * @since 1.0
	 */
	private function checkPDFCache() {
		return file_exists($this->PDFFilename);
	}
	
	/**
	 * Used to serve the cached PDF file as a download
	 * 
	 * @since 1.0
	 */
	private function serveCachedPDF($name) {
		// first load the file
		$handle = fopen ($this->PDFFilename, 'r'); 
		$data = fread($handle, filesize($this->PDFFilename));
		fclose($handle);
		
		$filesize = strlen($data);
	    $mimetype = 'application/octet-stream';
	    	
	    // Start sending headers
	    header("Pragma: public"); // required
	    header("Expires: 0");
	    header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
	    header("Cache-Control: private",false); // required for certain browsers
	    header("Content-Transfer-Encoding: binary");
	    header("Content-Type: " . $mimetype);
	    header("Content-Length: " . $filesize);
	    header("Content-Disposition: attachment; filename=\"" . $name . "\";" );
	
	    // Send data
	    echo $data;
	    die();
	}
}
?>