<?php

// $Id$

/**
 * @file
 * Base utilities used by the Islandora fedora module.
 */

if (!function_exists('str_getcsv')) {

  /**
   * Functions that emulate php5.3 functionality for backwards compatiablity
   * @param type $input
   * @param type $delimiter
   * @param type $enclosure
   * @param type $escape
   * @param type $eol
   * @return type 
   */
  function str_getcsv($input, $delimiter=',', $enclosure='"', $escape=NULL, $eol=NULL) {
    $temp = fopen("php://memory", "rw");
    fwrite($temp, $input);
    fseek($temp, 0);
    $r = fgetcsv($temp, 4096, $delimiter, $enclosure);
    fclose($temp);
    return $r;
  }

}

/**
 * 
 * Utility method to get data from a url location using curl_exec and return
 * 
 * This method takes identical parameters to do_curl_ext and passes them
 * directly to do_curl_ext.  The output from do_curl_ext is processed into
 * either a TRUE, FALSE, or NULL value.
 * 
 * This method exists for historical reasons as existing code makes use of
 * do_curl directly and expects a simple return value and not an array.
 * 
 * @param $url
 *   URL to be accessed by the function
 * @param $return_to_variable
 *   Indicates whether the resource accessed by the curl call (HTML page,
 *   XML page, etc.) is returned directly from the function to the calling
 *   program or if it is sent directly to output.
 * @param $number_of_post_vars
 *   Number of variable sot be posted
 * @param $post
 *   Whether the curl_exec is done as a "get" or a "post"
 *   
 * @return
 *   TRUE, FALSE, NULL, or the data returned from accessing the URL
 */
function do_curl($url, $return_to_variable = 1, $number_of_post_vars = 0, $post = NULL) {
  $return_array = do_curl_ext($url, $return_to_variable, $number_of_post_vars, $post);
  return ($return_array != NULL) ? $return_array[0] : NULL;
}

/**
 * 
 * Utility method to get data from a url location using curl_exec
 * 
 * This method takes a URL and three associated parameters and initializes the
 * structure required to make a call to curl_exec.  As a part of the
 * initialization the permissions associated with the (global) user are added
 * to the call.  This ensures access to any potentially user restricted URLs.
 * 
 * Various defaults are used for the parameters required by curl_exec including
 * the user agent and timeout.  These are hard-coded.
 * 
 * @param $url
 *   URL to be accessed by the function
 * @param $return_to_variable
 *   Indicates whether the resource accessed by the curl call (HTML page,
 *   XML page, etc.) is returned directly from the function to the calling
 *   program or if it is sent directly to output.
 * @param $number_of_post_vars
 *   Number of variable sot be posted
 * @param $post
 *   Whether the curl_exec is done as a "get" or a "post"
 *   
 * @return
 *   an array that consists of three value or NULL if curl is not suported:
 *   - element 0:
 *     The value returned from the curl_exec function call.
 *     This is either a TRUE or FALSE value or the actual data returned from
 *     accessing the URL.
 *   - element 1:
 *     The error code reslting from attempting to access the URL with curl_exec
 *   - element 2:
 *     A string representing a textual representation of the error code that
 *     resulted from attempting to access the URL with curl_exec
 */
function do_curl_ext($url, $return_to_variable = 1, $number_of_post_vars = 0, $post = NULL) {
  global $user;
  
  // Check if we are inside Drupal and there is a valid user.
  
  // If the user is not valid for a Fedora call curl will throw an exception.
  if ((!isset($user)) || $user->uid == 0) {
    $fedora_user = 'anonymous';
    $fedora_pass = 'anonymous';
  }
  else {
    $fedora_user = $user->name;
    $fedora_pass = $user->pass;
  }

  if (function_exists("curl_init")) {
    $ch = curl_init();
    $user_agent = "Mozilla/4.0 pp(compatible; MSIE 5.01; Windows NT 5.0)";
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, FALSE);
    curl_setopt($ch, CURLOPT_FAILONERROR, TRUE); // Fail on errors
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1); // allow redirects
    curl_setopt($ch, CURLOPT_TIMEOUT, 90); // times out after 90s
    curl_setopt($ch, CURLOPT_USERAGENT, $user_agent);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, $return_to_variable); // return into a variable
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_USERPWD, "$fedora_user:$fedora_pass");
    //curl_setopt($ch, CURLOPT_HTTPAUTH, CURLAUTH_ANY);
    if ($number_of_post_vars > 0 && $post) {
      curl_setopt($ch, CURLOPT_POST, $number_of_post_vars);
      curl_setopt($ch, CURLOPT_POSTFIELDS, "$post");
    }
    
    $ret_val = curl_exec($ch);
    
    $error_code = curl_errno($ch);
    $error_string = curl_error($ch);
    return array ($ret_val, $error_code, $error_string);
  }
  
  else {
    if (function_exists(drupal_set_message)) {
      drupal_set_message(t('No curl support.'), 'error');
    }
    return NULL;
  }
}

/**
 * Fedora available
 * @return type 
 */
function fedora_available() {

  $response = do_curl_ext(variable_get('fedora_base_url', 'http://localhost:8080/fedora') . '/describe');
  return ($response != NULL) ? ($response[1] == 0) : FALSE;
}

/**
 * Resource index search available
 * @return type 
 */
function risearch_available() {

  $response = do_curl_ext(variable_get('islandora_repository_url', 'http://localhost:8080/fedora/risearch'));
  return ($response != NULL) ? ($response[1] == 0): FALSE;
}


/**
 * Returns a UTF-8-encoded transcripiton of the string given in $in_str.
 * @param string $in_str
 * @return string A UTF-8 encoded string.
 */
function fix_encoding($in_str) {
  $cur_encoding = mb_detect_encoding($in_str);
  if ($cur_encoding == "UTF-8" && mb_check_encoding($in_str, "UTF-8")) {
    return $in_str;
  }
  else {
    return utf8_encode($in_str);
  }
}

/**
 * valid pid ??
 * @param type $pid
 * @return boolean 
 */
function valid_pid($pid) {
  $valid = FALSE;
  if (strlen(trim($pid)) <= 64 && preg_match('/^([A-Za-z0-9]|-|\.)+:(([A-Za-z0-9])|-|\.|~|_|(%[0-9A-F]{2}))+$/', trim($pid))) {
    $valid = TRUE;
  }

  return $valid;
}

/**
 * Valid Dsid ??
 * @param type $dsid
 * @return boolean 
 */
function valid_dsid($dsid) {
  $valid = FALSE;
  if (strlen(trim($dsid)) <= 64 && preg_match('/^[a-zA-Z0-9\_\-\.]+$/', trim($dsid))) {
    $valid = TRUE;
  }

  return $valid;
}

/**
 * fixDsid ??
 * @param type $dsid
 * @return string 
 */
function fix_dsid($dsid) {
  $new_dsid = trim($dsid);

  $find = '/[^a-zA-Z0-9\.\_\-]/';
  $replace = '';
  $new_dsid = preg_replace($find, $replace, $new_dsid);

  if (strlen($new_dsid) > 63)
    $new_dsid = substr($new_dsid, -63);

  if (preg_match('/^[^a-zA-Z]/', $dsid))
    $new_dsid = 'x' . $new_dsid;

  if (strlen($new_dsid) == 0)
    $new_dsid = 'item' . rand(1, 100);

  return $new_dsid;
}

/**
 * Function: get_collections_as_option_array
 *
 * Description: Returns an associative array of all collection objects in Fedora instance
 *
 * @return array
 */
function get_collections_as_option_array() {
  module_load_include('inc', 'islandora_repository', 'api/fedora_utils');
  $query = 'select $object $title from <#ri>
                            where ($object <dc:title> $title
                              and $object <info:fedora/fedora-system:def/model#hasModel> <info:fedora/islandora:collectionCModel>
                              and $object <fedora-model:state> <info:fedora/fedora-system:def/model#Active>)
                            order by $title';
  $url = variable_get('islandora_repository_url', 'http://localhost:8080/fedora/risearch');
  $url .= "?type=tuples&flush=true&format=csv&limit=1000&lang=itql&stream=on&query=";
  $content = do_curl($url . htmlentities(urlencode($query)));
  $list = explode("\n", $content);
  array_shift($list);
  $list = preg_replace('/info:fedora\//', '', $list);
  $options = array();
  foreach ($list as $item) {   //removes  blanks
    if ($item) {
      $parts = explode(',', $item);
      $options[$parts[0]] = $parts[1];
    }
  }
  unset($options['islandora:ContentModelCollection']);
  return $options;
}

/**
 * Function: get_content_models_as_option_array
 *
 * Description: Returns an associative array of all collection objects in Fedora instance
 *
 * @return array
 */
function get_content_models_as_option_array() {
  module_load_include('inc', 'islandora_repository', 'api/fedora_item');
  module_load_include('inc', 'islandora_repository', 'api/fedora_utils');
  $restricted = variable_get('fedora_namespace_restriction_enforced', true);
  $allowed_string = variable_get('fedora_pids_allowed', 'default: demo: changeme: islandora:');
  $namespaces = explode(':', $allowed_string);
  foreach ($namespaces as $namespace) {
    if ($namespace) {
      $allowed[] = trim($namespace);
    }
  }
  $query = 'select $object $title from <#ri>
          where ($object <dc:title> $title
          and ($object <fedora-model:hasModel> <info:fedora/fedora-system:ContentModel-3.0>
          or $object <fedora-rels-ext:isMemberOfCollection> <info:fedora/islandora:ContentModelsCollection>)
          and $object <fedora-model:state> <info:fedora/fedora-system:def/model#Active>)
          order by $title';

  $url = variable_get('islandora_repository_url', 'http://localhost:8080/fedora/risearch');
  $url .= "?type=tuples&flush=true&format=csv&limit=1000&lang=itql&stream=on&query=";
  $content = do_curl($url . htmlentities(urlencode($query)));
  $list = explode("\n", $content);
  array_shift($list);
  $list = preg_replace('/info:fedora\//', '', $list);
  foreach ($list as $item) {   //removes  blanks
    if ($item) {
      $parts = explode(',', $item);
      $item = new fedora_item($parts[0]);
      $nameparts = explode(':', $parts[0]);
      if (!$restricted || in_array($nameparts[0], $allowed))
        if ($item->get_datastream_dissemination('ISLANDORACM')) {
          $options[$parts[0]] = $parts[1]. ' ~ ' . $parts[0] ;
        }
    }
  }

  return $options;
}