In moodle, get a list of activities that are available and their index (order from the top down)

activity.php

<?php
require('../../config.php'); // adjust as needed
require_once($CFG->dirroot.'/course/format/lib.php');
require_once($CFG->libdir.'/modinfolib.php');

$courseid = 26; // the numerical id of the course we are looking in
$index = 1;
$course = get_course($courseId); // in course/format/lib.php
$modinfo = get_fast_modinfo($course); // in lib/modinfolib.php

foreach ($modinfo->get_cms() as $cmid => $cm) {
  if ($cm->uservisible && $cm->available) {
      echo PHP_EOL . $index, ". ", $cmid, " name=", $cm->modname, ", name=" . $cm->name;// $cm is a cm_info;
      // $url = new moodle_url("/mod/" . $cm->modname . "/view.php", array("id" => $cmid));
      $index++;
  }
}