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   1  <?php
   2  // This file is part of Moodle - http://moodle.org/
   3  //
   4  // Moodle is free software: you can redistribute it and/or modify
   5  // it under the terms of the GNU General Public License as published by
   6  // the Free Software Foundation, either version 3 of the License, or
   7  // (at your option) any later version.
   8  //
   9  // Moodle is distributed in the hope that it will be useful,
  10  // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  // GNU General Public License for more details.
  13  //
  14  // You should have received a copy of the GNU General Public License
  15  // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16  
  17  namespace core;
  18  
  19  /**
  20   * User Alert notifications.
  21   *
  22   * @package    core
  23   * @copyright  2016 Andrew Nicols <andrew@nicols.co.uk>
  24   * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  25   */
  26  
  27  defined('MOODLE_INTERNAL') || die();
  28  
  29  class notification {
  30      /**
  31       * A notification of level 'success'.
  32       */
  33      const SUCCESS = 'success';
  34  
  35      /**
  36       * A notification of level 'warning'.
  37       */
  38      const WARNING = 'warning';
  39  
  40      /**
  41       * A notification of level 'info'.
  42       */
  43      const INFO = 'info';
  44  
  45      /**
  46       * A notification of level 'error'.
  47       */
  48      const ERROR = 'error';
  49  
  50      /**
  51       * Add a message to the session notification stack.
  52       *
  53       * @param string $message The message to add to the stack
  54       * @param string $level   The type of message to add to the stack
  55       */
  56      public static function add($message, $level = null) {
  57          global $PAGE, $SESSION;
  58  
  59          if ($PAGE && $PAGE->state === \moodle_page::STATE_IN_BODY) {
  60              // Currently in the page body - just render and exit immediately.
  61              // We insert some code to immediately insert this into the user-notifications created by the header.
  62              $id = uniqid();
  63              echo \html_writer::span(
  64                  $PAGE->get_renderer('core')->render(new \core\output\notification($message, $level)),
  65                  '', array('id' => $id));
  66  
  67              // Insert this JS here using a script directly rather than waiting for the page footer to load to avoid
  68              // ensure that the message is added to the user-notifications section as soon as possible after it is created.
  69              echo \html_writer::script(
  70                      "(function() {" .
  71                          "var notificationHolder = document.getElementById('user-notifications');" .
  72                          "if (!notificationHolder) { return; }" .
  73                          "var thisNotification = document.getElementById('{$id}');" .
  74                          "if (!thisNotification) { return; }" .
  75                          "notificationHolder.appendChild(thisNotification.firstChild);" .
  76                          "thisNotification.remove();" .
  77                      "})();"
  78                  );
  79              return;
  80          }
  81  
  82          // Add the notification directly to the session.
  83          // This will either be fetched in the header, or by JS in the footer.
  84          if (!isset($SESSION->notifications) || !array($SESSION->notifications)) {
  85              $SESSION->notifications = [];
  86          }
  87          $SESSION->notifications[] = (object) array(
  88              'message'   => $message,
  89              'type'      => $level,
  90          );
  91      }
  92  
  93      /**
  94       * Fetch all of the notifications in the stack and clear the stack.
  95       *
  96       * @return array All of the notifications in the stack
  97       */
  98      public static function fetch() {
  99          global $SESSION;
 100  
 101          if (!isset($SESSION) || !isset($SESSION->notifications)) {
 102              return [];
 103          }
 104  
 105          $notifications = $SESSION->notifications;
 106          unset($SESSION->notifications);
 107  
 108          $renderables = [];
 109          foreach ($notifications as $notification) {
 110              $renderable = new \core\output\notification($notification->message, $notification->type);
 111              $renderables[] = $renderable;
 112          }
 113  
 114          return $renderables;
 115      }
 116  
 117      /**
 118       * Fetch all of the notifications in the stack and clear the stack.
 119       *
 120       * @return array All of the notifications in the stack
 121       */
 122      public static function fetch_as_array(\renderer_base $renderer) {
 123          $notifications = [];
 124          foreach (self::fetch() as $notification) {
 125              $notifications[] = [
 126                  'template'  => $notification->get_template_name(),
 127                  'variables' => $notification->export_for_template($renderer),
 128              ];
 129          }
 130          return $notifications;
 131      }
 132  
 133      /**
 134       * Add a success message to the notification stack.
 135       *
 136       * @param string $message The message to add to the stack
 137       */
 138      public static function success($message) {
 139          return self::add($message, self::SUCCESS);
 140      }
 141  
 142      /**
 143       * Add a info message to the notification stack.
 144       *
 145       * @param string $message The message to add to the stack
 146       */
 147      public static function info($message) {
 148          return self::add($message, self::INFO);
 149      }
 150  
 151      /**
 152       * Add a warning message to the notification stack.
 153       *
 154       * @param string $message The message to add to the stack
 155       */
 156      public static function warning($message) {
 157          return self::add($message, self::WARNING);
 158      }
 159  
 160      /**
 161       * Add a error message to the notification stack.
 162       *
 163       * @param string $message The message to add to the stack
 164       */
 165      public static function error($message) {
 166          return self::add($message, self::ERROR);
 167      }
 168  }