<?php
  	function explore($current_dir,$sub_dirs,$num_of_results) {
  		$return = array();
  		// Search for pdfs in sub directories.
  		foreach ($sub_dirs as $dir) {
  			$pdfs = \OC_FileCache::searchByMime('application', 'pdf', '/'.\OCP\USER::getUser().'/files'.$current_dir.$dir.'/');
  			sort($pdfs);
  			$max_count = min(count($pdfs),$num_of_results);
  			$thumbs = array();
  			for ($i = $max_count - 1; $i >= 0; $i--) {
  				if (!in_array($pdfs[$i],$thumbs)) 
  					$thumbs[] = $pdfs[$i];
  			}
  			$return[] = array($dir,$thumbs); 
  		}
  		return $return; 
  	}
  	
  ?>