<?php
  /**
   * ownCloud - Documents App
   *
   * @author Victor Dubiniuk
   * @copyright 2013 Victor Dubiniuk victor.dubiniuk@gmail.com
   *
   * This file is licensed under the Affero General Public License version 3 or
   * later.
   */
  
  namespace OCA\Documents;
  
  /**
   * Class processing range HTTP request (partial download)
   */
  class Download_Range extends \OCA\Documents\Download {
  
  	// Start of the range
  	protected $start;
  	// End of the range
  	protected $end;
  
  	/**
  	 * Build download model to serve HTTP_RANGE
  	 * @param type $view - filesystem view
  	 * @param type $filepath - path to the file relative to this view root
  	 */
  	public function __construct($owner, $filepath){
  		$this->view = $this->getView($owner);
  		$this->filepath = $filepath;
  	}
  
  	/**
  	 * Send the requested parts of the file
  	 */
  	public function sendResponse(){
  		if (!preg_match('/^bytes=\d*-\d*(,\d*-\d*)*$/', $_SERVER['HTTP_RANGE'])){
  			$this->sendNotSatisfiable();
  		}
  		$ranges = explode(',', substr($_SERVER['HTTP_RANGE'], 6));
  		foreach ($ranges as $range){
  			$parts = explode('-', $range);
  
  			$start = isset($parts[0]) ? $parts[0] : 0;
  			$end = isset($parts[1]) ? $parts[1] : $this->getFilesize() - 1;
  
  			if ($start > $end){
  				$this->sendNotSatisfiable();
  			}
  
  			$handle = $this->view->fopen($this->filepath, 'rb');
  			\fseek($handle, $start);
  			$buffer = \fread($handle, $end - $start);
  			$md5Sum = md5($buffer);
  			\fclose($handle);
  			// send the headers and data 
  			header("Content-Length: " . $end - $start);
  			header("Content-md5: " . $md5Sum);
  			header("Accept-Ranges: bytes");
  			header('Content-Range: bytes ' . $start . '-' . ($end) . '/' . $this->getFilesize());
  			header("Connection: close");
  			header("Content-type: " . $this->getMimeType());
  			header('Content-Disposition: attachment; filename=' . $this->getFilename());
  			\OC_Util::obEnd();
  			echo $buffer;
  			flush();
  		}
  	}
  
  	/**
  	 * Send 416 if we can't satisfy the requested ranges
  	 */
  	protected function sendNotSatisfiable(){
  		header('HTTP/1.1 416 Requested Range Not Satisfiable');
  		header('Content-Range: bytes */' . $this->getFilesize()); // Required in 416.
  		exit;
  	}
  }