Generating lists of download links

<?php

// Shows all files in the newsletter directory,
// descending by year,
// assending by issue number within each year.

// Filenames must be in format: yyyy-nn-MonthName
// e.g. 2007-02-February

$newline = "<br/>";
$dir = $modx->config['base_path'].'assets/newsletters'; // set path to newsletter files
$dir_array = array(); // main array - contains all file names in directory
$temp_array = array(); // temp array used to hold one year's file names

// open directory and parse file list 
if (is_dir($dir)) { 
   if ($dh = opendir($dir)) { 
   
      // iterate over file list to create full directory array
      
      while (($filename = readdir($dh)) !== false) { 
          if (($filename != ".") && ($filename != "..") && ($filename != "WS_FTP.LOG")) { // skip self, parent, and ftp log

		  	$dir_array[] = $filename; // add the filename to the array

          } 
      } 

      closedir($dh);  // close directory 
   }
   natsort($dir_array); // sort in ascending order by year and issue number
   $dir_array = array_reverse($dir_array, false); // reverse array (descending by year)
      
   $year = ""; // used for comparison to find new year
   $i = 0;
   $n = count($dir_array); // total number of files
   
   for($i=0;$i<$n;$i++) {  // can't use foreach() here -- need to manipulate index
	    
   		$file_year = substr($dir_array[$i],0,4);  // year is first four characters of file name
		
		if ($file_year != $year) {  // new year
			echo "<h3>    ",$file_year,"</h3>";
			
			$j = $i;  // set j (temporary index) to beginning of the new year
			
			$temp_array=array(); // empty $temp_array
			$year = $file_year;  // set $year to current year
			while($year == substr($dir_array[$j],0,4)) {  // build temp array for one year
			
			    if ($j > $n) {  // don't go beyond end of full array
					break;
				}
				//$value = $dir_array[$j];
				//$temp_array[] = $value;
				$temp_array[] = $dir_array[$j];  // add one issue to temp_array
				
				$j++;
			}
			
			
			$temp_array = array_reverse($temp_array, false); // reverse array to show ascending months
			
			foreach($temp_array as $temp_value) {  // create one year's links on screen
			
			    $link = $modx->config['base_url'].'assets/newsletters/'.$temp_value;
        
				echo '        <a href ="';
	         	echo $link;
      			echo '">';
				echo $temp_value;
				echo '</a>';
             	echo $newline;
			}
			$j--;  // decrement j because we went one too far
			$i = $j;  // set  main index to beginning of next year
			$year = $file_year;  // set $file year for start of new year
		}
  
 
	}
 
} 
echo $newline;

?>