<?php

  // Get link from url
  // Should be in format of {username}/{encoded_id}/files/{path}
  // {node_id} can be omitted so that it always points to the latest revision
  // Example: ?link=atlassian/rKGEo/files/snippet.txt
  $link = filter_input(INPUT_GET, 'link', FILTER_SANITIZE_URL);
	
  if (empty($link)) {
    trigger_error('Link parameter must be specified.', E_USER_ERROR); 
  }
  
  // URL for Bitbucket Snippets API
  $bb = 'https://bitbucket.org/!api/2.0/snippets/';

  // Add link to Bitbucket URL
  $url = $bb . $link;

  // Temp file needed to get mime type
  $tmpfname = tempnam(sys_get_temp_dir(), "bitbucket_snippet_");
  $fp = fopen($tmpfname, "w");
  
  // Setup curl parameters for download
  $ch = curl_init();
  curl_setopt($ch, CURLOPT_URL, $url);
  curl_setopt($ch, CURLOPT_FILE, $fp);
  // Must be set to true so that PHP follows any "Location:" header
  curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);	  
  
  // Download file
  curl_exec($ch);
  
  // Close temp file
  fclose($fp);
  
  // Get HTTP status code
  $code = curl_getinfo($ch, CURLINFO_HTTP_CODE);
  
  if ($code != 200) {
    $output = "No cURL data returned for $url [". $code. "]";
    if (curl_error($ch)) {
      $output .= "\n". curl_error($ch);
    }
    trigger_error($output, E_USER_ERROR); 
  }
  
  // Close connection
  curl_close($ch);
  
  if (filesize($tmpfname) < 1) {
	trigger_error("Error retrieving file.", E_USER_ERROR); 
  }

  // Set Content Type header from file since Bitbucket does not return proper Content Type
  // Must use special magic file for programming files
  // https://bitbucket.org/snippets/mythics/yjLgz/
  $finfo = new finfo(FILEINFO_MIME_TYPE, '/usr/local/apache/conf/programming.magic');
  $mime = $finfo->file($tmpfname);
  header('Content-Type: ' . $mime);

  // Output file to browser
  readfile($tmpfname);
  
  // Delete temp file
  unlink($tmpfname);
?>