<?php
  /**
   * @package dompdf
   * @link    http://dompdf.github.com/
   * @author  Benj Carson <benjcarson@digitaljunkies.ca>
   * @author  Helmut Tischer <htischer@weihenstephan.org>
   * @author  Fabien Ménager <fabien.menager@gmail.com>
   * @license http://www.gnu.org/copyleft/lesser.html GNU Lesser General Public License
   */
  namespace Dompdf\Image;
  
  use Dompdf\Dompdf;
  use Dompdf\Helpers;
  use Dompdf\Exception\ImageException;
  
  /**
   * Static class that resolves image urls and downloads and caches
   * remote images if required.
   *
   * @package dompdf
   */
  class Cache
  {
      /**
       * Array of downloaded images.  Cached so that identical images are
       * not needlessly downloaded.
       *
       * @var array
       */
      protected static $_cache = array();
  
      /**
       * The url to the "broken image" used when images can't be loaded
       *
       * @var string
       */
      public static $broken_image = "data:image/png;base64,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";
  
      /**
       * Current dompdf instance
       *
       * @var Dompdf
       */
      protected static $_dompdf;
  
      /**
       * Resolve and fetch an image for use.
       *
       * @param string $url The url of the image
       * @param string $protocol Default protocol if none specified in $url
       * @param string $host Default host if none specified in $url
       * @param string $base_path Default path if none specified in $url
       * @param Dompdf $dompdf The Dompdf instance
       *
       * @throws ImageException
       * @return array             An array with two elements: The local path to the image and the image extension
       */
      static function resolve_url($url, $protocol, $host, $base_path, Dompdf $dompdf)
      {
          self::$_dompdf = $dompdf;
  
          $protocol = mb_strtolower($protocol);
          $parsed_url = Helpers::explode_url($url);
          $message = null;
  
          $remote = ($protocol && $protocol !== "file://") || ($parsed_url['protocol'] != "");
  
          $data_uri = strpos($parsed_url['protocol'], "data:") === 0;
          $full_url = null;
          $enable_remote = $dompdf->get_option("enable_remote");
  
          try {
  
              // Remote not allowed and is not DataURI
              if (!$enable_remote && $remote && !$data_uri) {
                  throw new ImageException("Remote file access is disabled.", E_WARNING);
              } // Remote allowed or DataURI
              else {
                  if ($enable_remote && $remote || $data_uri) {
                      // Download remote files to a temporary directory
                      $full_url = Helpers::build_url($protocol, $host, $base_path, $url);
  
                      // From cache
                      if (isset(self::$_cache[$full_url])) {
                          $resolved_url = self::$_cache[$full_url];
                      } // From remote
                      else {
                          $tmp_dir = $dompdf->get_option("temp_dir");
                          $resolved_url = tempnam($tmp_dir, "ca_dompdf_img_");
                          $image = "";
  
                          if ($data_uri) {
                              if ($parsed_data_uri = Helpers::parse_data_uri($url)) {
                                  $image = $parsed_data_uri['data'];
                              }
                          } else {
                              set_error_handler(array("\\Dompdf\\Helpers", "record_warnings"));
                              $image = file_get_contents($full_url, null, $dompdf->getHttpContext());
                              restore_error_handler();
                          }
  
                          // Image not found or invalid
                          if (strlen($image) == 0) {
                              $msg = ($data_uri ? "Data-URI could not be parsed" : "Image not found");
                              throw new ImageException($msg, E_WARNING);
                          } // Image found, put in cache and process
                          else {
                              //e.g. fetch.php?media=url.jpg&cache=1
                              //- Image file name might be one of the dynamic parts of the url, don't strip off!
                              //- a remote url does not need to have a file extension at all
                              //- local cached file does not have a matching file extension
                              //Therefore get image type from the content
                              file_put_contents($resolved_url, $image);
                          }
                      }
                  } // Not remote, local image
                  else {
                      $resolved_url = Helpers::build_url($protocol, $host, $base_path, $url);
                  }
              }
  
              // Check if the local file is readable
              if (!is_readable($resolved_url) || !filesize($resolved_url)) {
                  throw new ImageException("Image not readable or empty", E_WARNING);
              } // Check is the file is an image
              else {
                  list($width, $height, $type) = Helpers::dompdf_getimagesize($resolved_url, $dompdf->getHttpContext());
  
                  // Known image type
                  if ($width && $height && in_array($type, array("gif", "png", "jpeg", "bmp", "svg"))) {
                      //Don't put replacement image into cache - otherwise it will be deleted on cache cleanup.
                      //Only execute on successful caching of remote image.
                      if ($enable_remote && $remote || $data_uri) {
                          self::$_cache[$full_url] = $resolved_url;
                      }
                  } // Unknown image type
                  else {
                      throw new ImageException("Image type unknown", E_WARNING);
                  }
              }
          } catch (ImageException $e) {
              $resolved_url = self::$broken_image;
              $type = "png";
              $message = "Image not found or type unknown";
              Helpers::record_warnings($e->getCode(), $e->getMessage() . " 
   $url", $e->getFile(), $e->getLine());
          }
  
          return array($resolved_url, $type, $message);
      }
  
      /**
       * Unlink all cached images (i.e. temporary images either downloaded
       * or converted)
       */
      static function clear()
      {
          if (empty(self::$_cache) || self::$_dompdf->get_option("debugKeepTemp")) {
              return;
          }
  
          foreach (self::$_cache as $file) {
              if (self::$_dompdf->get_option("debugPng")) {
                  print "[clear unlink $file]";
              }
              unlink($file);
          }
  
          self::$_cache = array();
      }
  
      static function detect_type($file, $context = null)
      {
          list(, , $type) = Helpers::dompdf_getimagesize($file, $context);
  
          return $type;
      }
  
      static function is_broken($url)
      {
          return $url === self::$broken_image;
      }
  }
  
  if (file_exists(realpath(__DIR__ . "/../../lib/res/broken_image.png"))) {
      Cache::$broken_image = realpath(__DIR__ . "/../../lib/res/broken_image.png");
  }