<?php

/**
 * @file
 * Mimetype specific utility functions.
 */

/**
 * Retrieve the correct file extension for a give mimetype.
 *
 * @param string $mimetype
 *   The mimetype whose extension is required.
 *
 * @return string
 *   The extension mapped to the given mimetype. Defaults to 'bin'.
 */
function islandora_get_extension_for_mimetype($mimetype) {
  // file.mimetypes.inc is a part of Drupal core, however is not
  // automatically loaded. Manually require it.
  require_once DRUPAL_ROOT . "/includes/file.mimetypes.inc";
  $extension = 'bin';
  $mimetype_mapping = file_mimetype_mapping();
  $extension_index = array_search($mimetype, $mimetype_mapping['mimetypes']);
  if ($extension_index !== FALSE) {
    $mime_array_flipped = array_reverse($mimetype_mapping['extensions']);
    $extension = array_search($extension_index, $mime_array_flipped);
  }

  // We can only have one mapping in drupal for 'xml'.
  if ($mimetype == "text/xml") {
    return "xml";
  }
  return $extension;
}

/**
 * Retrieve all file extensions for a give mimetype.
 *
 * @param string $mimetype
 *   The mimetype whose extensions are required.
 *
 * @return array
 *   All known legal extensions.
 */
function islandora_get_extensions_for_mimetype($mimetype) {
  // file.mimetypes.inc is a part of Drupal core, however is not
  // automatically loaded. Manually require it.
  require_once DRUPAL_ROOT . "/includes/file.mimetypes.inc";
  $mimetype_mapping = file_mimetype_mapping();
  $index = array_search($mimetype, $mimetype_mapping['mimetypes']);
  $extensions = array();
  if ($index !== FALSE) {
    $extensions = array_keys($mimetype_mapping['extensions'], $index);
  }
  // We can only have one mapping in drupal for 'xml'.
  if ($mimetype == "text/xml") {
    $extensions[] = 'xml';
  }
  return $extensions;
}

/**
 * Extensions for the mimes accepted by a datastream.
 *
 * @param AbstractObject $object
 *   Object to check for extensions.
 * @param string $dsid
 *   Datastream ID to check for extensions.
 *
 * @return string[]
 *   Extensions for the mimes accepted by the datastream ID on the object.
 */
function islandora_get_extensions_for_datastream(AbstractObject $object, $dsid) {
  module_load_include('inc', 'islandora', 'includes/utilities');
  $datastream_mime_map = islandora_get_datastreams_requirements_from_models($object->models);
  $mimes = isset($datastream_mime_map[$dsid]) ? $datastream_mime_map[$dsid]['mime'] : array();
  if (isset($object[$dsid])) {
    $current_mime = $object[$dsid]->mimetype;
    if (!in_array($current_mime, $mimes)) {
      $mimes[] = $current_mime;
    }
  }
  $extensions = array();
  foreach ($mimes as $mime) {
    $extensions = array_merge($extensions, islandora_get_extensions_for_mimetype($mime));
  }
  return array_unique($extensions);
}