public function page_index() {
        global $CFG;
        $output = '';
        // Checking wiki instance
        if (!$wiki = wiki_get_wiki($this->page->cm->instance)) {
            return false;
        }

        // @TODO: Fix call to wiki_get_subwiki_by_group
        $gid = groups_get_activity_group($this->page->cm);
        $gid = !empty($gid) ? $gid : 0;
        if (!$subwiki = wiki_get_subwiki_by_group($this->page->cm->instance, $gid)) {
            return false;
        }
        $swid = $subwiki->id;
        $pages = wiki_get_page_list($swid);
        $selectoptions = array();
        foreach ($pages as $page) {
            $selectoptions[$page->id] = $page->title;
        }
        $label = get_string('pageindex', 'wiki') . ': ';
        $select = new single_select(new moodle_url('/mod/wiki/view.php'), 'pageid', $selectoptions);
        $select->label = $label;
        return $this->output->container($this->output->render($select), 'wiki_index');
    }

function wiki_extend_navigation(navigation_node $navref, $course, $module, $cm)
{
    global $CFG, $PAGE, $USER;
    require_once $CFG->dirroot . '/mod/wiki/locallib.php';
    $context = context_module::instance($cm->id);
    $url = $PAGE->url;
    $userid = 0;
    if ($module->wikimode == 'individual') {
        $userid = $USER->id;
    }
    if (!($wiki = wiki_get_wiki($cm->instance))) {
        return false;
    }
    if (!($gid = groups_get_activity_group($cm))) {
        $gid = 0;
    }
    if (!($subwiki = wiki_get_subwiki_by_group($cm->instance, $gid, $userid))) {
        return null;
    } else {
        $swid = $subwiki->id;
    }
    $pageid = $url->param('pageid');
    $cmid = $url->param('id');
    if (empty($pageid) && !empty($cmid)) {
        // wiki main page
        $page = wiki_get_page_by_title($swid, $wiki->firstpagetitle);
        $pageid = $page->id;
    }
    if (wiki_can_create_pages($context)) {
        $link = new moodle_url('/mod/wiki/create.php', array('action' => 'new', 'swid' => $swid));
        $node = $navref->add(get_string('newpage', 'wiki'), $link, navigation_node::TYPE_SETTING);
    }
    if (is_numeric($pageid)) {
        if (has_capability('mod/wiki:viewpage', $context)) {
            $link = new moodle_url('/mod/wiki/view.php', array('pageid' => $pageid));
            $node = $navref->add(get_string('view', 'wiki'), $link, navigation_node::TYPE_SETTING);
        }
        if (wiki_user_can_edit($subwiki)) {
            $link = new moodle_url('/mod/wiki/edit.php', array('pageid' => $pageid));
            $node = $navref->add(get_string('edit', 'wiki'), $link, navigation_node::TYPE_SETTING);
        }
        if (has_capability('mod/wiki:viewcomment', $context)) {
            $link = new moodle_url('/mod/wiki/comments.php', array('pageid' => $pageid));
            $node = $navref->add(get_string('comments', 'wiki'), $link, navigation_node::TYPE_SETTING);
        }
        if (has_capability('mod/wiki:viewpage', $context)) {
            $link = new moodle_url('/mod/wiki/history.php', array('pageid' => $pageid));
            $node = $navref->add(get_string('history', 'wiki'), $link, navigation_node::TYPE_SETTING);
        }
        if (has_capability('mod/wiki:viewpage', $context)) {
            $link = new moodle_url('/mod/wiki/map.php', array('pageid' => $pageid));
            $node = $navref->add(get_string('map', 'wiki'), $link, navigation_node::TYPE_SETTING);
        }
        if (has_capability('mod/wiki:viewpage', $context)) {
            $link = new moodle_url('/mod/wiki/files.php', array('pageid' => $pageid));
            $node = $navref->add(get_string('files', 'wiki'), $link, navigation_node::TYPE_SETTING);
        }
        if (has_capability('mod/wiki:managewiki', $context)) {
            $link = new moodle_url('/mod/wiki/admin.php', array('pageid' => $pageid));
            $node = $navref->add(get_string('admin', 'wiki'), $link, navigation_node::TYPE_SETTING);
        }
    }
}

// User ID
$groupanduser = optional_param('groupanduser', null, PARAM_TEXT);
if (!($page = wiki_get_page($pageid))) {
    print_error('incorrectpageid', 'wiki');
}
if ($groupanduser) {
    list($currentgroup, $userid) = explode('-', $groupanduser);
    $currentgroup = clean_param($currentgroup, PARAM_INT);
    $userid = clean_param($userid, PARAM_INT);
}
if ($wid) {
    // in group mode
    if (!($wiki = wiki_get_wiki($wid))) {
        print_error('incorrectwikiid', 'wiki');
    }
    if (!($subwiki = wiki_get_subwiki_by_group($wiki->id, $currentgroup, $userid))) {
        // create subwiki if doesn't exist
        $subwikiid = wiki_add_subwiki($wiki->id, $currentgroup, $userid);
        $subwiki = wiki_get_subwiki($subwikiid);
    }
} else {
    // no group
    if (!($subwiki = wiki_get_subwiki($page->subwikiid))) {
        print_error('incorrectsubwikiid', 'wiki');
    }
    // Checking wiki instance of that subwiki
    if (!($wiki = wiki_get_wiki($subwiki->wikiid))) {
        print_error('incorrectwikiid', 'wiki');
    }
}
// Checking course module instance

    function create_page($pagetitle) {
        global $USER, $PAGE;

        $data = $this->mform->get_data();
        if (isset($data->groupinfo)) {
            $groupid = $data->groupinfo;
        } else if (!empty($this->gid)) {
            $groupid = $this->gid;
        } else {
            $groupid = '0';
        }
        if (empty($this->subwiki)) {
            // If subwiki is not set then try find one and set else create one.
            if (!$this->subwiki = wiki_get_subwiki_by_group($this->wid, $groupid, $this->uid)) {
                $swid = wiki_add_subwiki($PAGE->activityrecord->id, $groupid, $this->uid);
                $this->subwiki = wiki_get_subwiki($swid);
            }
        }
        if ($data) {
            $this->set_title($data->pagetitle);
            $id = wiki_create_page($this->subwiki->id, $data->pagetitle, $data->pageformat, $USER->id);
        } else {
            $this->set_title($pagetitle);
            $id = wiki_create_page($this->subwiki->id, $pagetitle, $PAGE->activityrecord->defaultformat, $USER->id);
        }
        $this->page = $id;
        return $id;
    }

$group = optional_param('group', 0, PARAM_INT);
$uid = optional_param('uid', 0, PARAM_INT);
// 'create' action must be submitted by moodle form
// so sesskey must be checked
if ($action == 'create') {
    if (!confirm_sesskey()) {
        print_error('invalidsesskey');
    }
}
if (!empty($swid)) {
    $subwiki = wiki_get_subwiki($swid);
    if (!($wiki = wiki_get_wiki($subwiki->wikiid))) {
        print_error('incorrectwikiid', 'wiki');
    }
} else {
    $subwiki = wiki_get_subwiki_by_group($wid, $group, $uid);
    if (!($wiki = wiki_get_wiki($wid))) {
        print_error('incorrectwikiid', 'wiki');
    }
}
if (!($cm = get_coursemodule_from_instance('wiki', $wiki->id))) {
    print_error('invalidcoursemodule');
}
$groups = new stdClass();
if (groups_get_activity_groupmode($cm)) {
    $modulecontext = context_module::instance($cm->id);
    $canaccessgroups = has_capability('moodle/site:accessallgroups', $modulecontext);
    if ($canaccessgroups) {
        $groups->availablegroups = groups_get_all_groups($cm->course);
        $allpart = new stdClass();
        $allpart->id = '0';

    if ($wiki->wikimode == 'individual' && ($groupmode == SEPARATEGROUPS || $groupmode == VISIBLEGROUPS)) {
        list($gid, $uid) = explode('-', $groupanduser);
    } else if ($wiki->wikimode == 'individual') {
        $gid = 0;
        $uid = $userid;
    } else if ($groupmode == NOGROUPS) {
        $gid = 0;
        $uid = 0;
    } else {
        $gid = $currentgroup;
        $uid = 0;
    }

    // Getting subwiki instance. If it does not exists, redirect to create page
    if (!$subwiki = wiki_get_subwiki_by_group($wiki->id, $gid, $uid)) {
        $context = context_module::instance($cm->id);

        $modeanduser = $wiki->wikimode == 'individual' && $uid != $USER->id;
        $modeandgroupmember = $wiki->wikimode == 'collaborative' && !groups_is_member($gid);

        $manage = has_capability('mod/wiki:managewiki', $context);
        $edit = has_capability('mod/wiki:editpage', $context);
        $manageandedit = $manage && $edit;

        if ($groupmode == VISIBLEGROUPS and ($modeanduser || $modeandgroupmember) and !$manageandedit) {
            print_error('nocontent','wiki');
        }

        $params = array('wid' => $wiki->id, 'group' => $gid, 'uid' => $uid, 'title' => $title);
        $url = new moodle_url('/mod/wiki/create.php', $params);

if ($subwikiid) {
    // Subwiki id is specified.
    $subwiki = wiki_get_subwiki($subwikiid);
    if (!$subwiki || $subwiki->wikiid != $wiki->id) {
        print_error('incorrectsubwikiid', 'wiki');
    }
} else {
    // Getting current group id
    $gid = groups_get_activity_group($cm);
    // Getting current user id
    if ($wiki->wikimode == 'individual') {
        $userid = $userid ? $userid : $USER->id;
    } else {
        $userid = 0;
    }
    if (!($subwiki = wiki_get_subwiki_by_group($cm->instance, $gid, $userid))) {
        // Subwiki does not exist yet, redirect to the view page (which will redirect to create page if allowed).
        $params = array('wid' => $wiki->id, 'group' => $gid, 'uid' => $userid, 'title' => $wiki->firstpagetitle);
        $url = new moodle_url('/mod/wiki/view.php', $params);
        redirect($url);
    }
}
if ($subwiki && !wiki_user_can_view($subwiki, $wiki)) {
    print_error('cannotviewpage', 'wiki');
}
$wikipage = new page_wiki_search($wiki, $subwiki, $cm);
$wikipage->set_search_string($search, $searchcontent);
$wikipage->set_title(get_string('search'));
$wikipage->print_header();
$wikipage->print_content();
$wikipage->print_footer();

 function create_page($pagetitle)
 {
     global $USER, $PAGE;
     $data = $this->mform->get_data();
     if (isset($data->groupinfo)) {
         $groupid = $data->groupinfo;
     } else {
         $groupid = '0';
     }
     if (!($this->subwiki = wiki_get_subwiki_by_group($this->wid, $groupid))) {
         $swid = wiki_add_subwiki($PAGE->activityrecord->id, $groupid, $this->uid);
         $this->subwiki = wiki_get_subwiki($swid);
     }
     if ($data) {
         $this->set_title($data->pagetitle);
         $id = wiki_create_page($this->subwiki->id, $data->pagetitle, $data->pageformat, $USER->id);
     } else {
         $this->set_title($pagetitle);
         $id = wiki_create_page($this->subwiki->id, $pagetitle, $PAGE->activityrecord->defaultformat, $USER->id);
     }
     $this->page = $id;
     return $id;
 }

/**
 * Utility function for getting a subwiki by group and user, validating that the user can view it.
 * If the subwiki doesn't exists in DB yet it'll have id -1.
 *
 * @param stdClass $wiki The wiki.
 * @param int $groupid Group ID. 0 means the subwiki doesn't use groups.
 * @param int $userid User ID. 0 means the subwiki doesn't use users.
 * @return stdClass Subwiki. If it doesn't exists in DB yet it'll have id -1. If the user can't view the
 *                  subwiki this function will return false.
 * @since  Moodle 3.1
 * @throws moodle_exception
 */
function wiki_get_subwiki_by_group_and_user_with_validation($wiki, $groupid, $userid)
{
    global $USER, $DB;
    // Get subwiki based on group and user.
    if (!($subwiki = wiki_get_subwiki_by_group($wiki->id, $groupid, $userid))) {
        // The subwiki doesn't exist.
        // Validate if user is valid.
        if ($userid != 0) {
            $user = core_user::get_user($userid, '*', MUST_EXIST);
            core_user::require_active_user($user);
        }
        // Validate that groupid is valid.
        if ($groupid != 0 && !groups_group_exists($groupid)) {
            throw new moodle_exception('cannotfindgroup', 'error');
        }
        // Valid data but subwiki not found. We'll simulate a subwiki object to check if the user would be able to see it
        // if it existed. If he's able to see it then we'll return an empty array because the subwiki has no pages.
        $subwiki = new stdClass();
        $subwiki->id = -1;
        $subwiki->wikiid = $wiki->id;
        $subwiki->userid = $userid;
        $subwiki->groupid = $groupid;
    }
    // Check that the user can view the subwiki. This function checks capabilities.
    if (!wiki_user_can_view($subwiki, $wiki)) {
        return false;
    }
    return $subwiki;
}

/**
 * Get a sub wiki instance by wiki id, group id and user id.
 * If the wiki doesn't exist in DB it will return an isntance with id -1.
 *
 * @param int $wikiid  Wiki ID.
 * @param int $groupid Group ID.
 * @param int $userid  User ID.
 * @return object      Subwiki instance.
 * @since Moodle 3.1
 */
function wiki_get_possible_subwiki_by_group($wikiid, $groupid, $userid = 0)
{
    if (!($subwiki = wiki_get_subwiki_by_group($wikiid, $groupid, $userid))) {
        $subwiki = new stdClass();
        $subwiki->id = -1;
        $subwiki->wikiid = $wikiid;
        $subwiki->groupid = $groupid;
        $subwiki->userid = $userid;
    }
    return $subwiki;
}

 /**
  * Generates a page in wiki.
  *
  * @param stdClass wiki object returned from create_instance (if known)
  * @param stdClass|array $record data to insert as wiki entry.
  * @return stdClass
  * @throws coding_exception if neither $record->wikiid nor $wiki->id is specified
  */
 public function create_page($wiki, $record = array())
 {
     global $CFG, $USER;
     require_once $CFG->dirroot . '/mod/wiki/locallib.php';
     $this->pagecount++;
     $record = (array) $record + array('title' => 'wiki page ' . $this->pagecount, 'wikiid' => $wiki->id, 'subwikiid' => 0, 'group' => 0, 'content' => 'Wiki page content ' . $this->pagecount, 'format' => $wiki->defaultformat);
     if (empty($record['wikiid']) && empty($record['subwikiid'])) {
         throw new coding_exception('wiki page generator requires either wikiid or subwikiid');
     }
     if (!$record['subwikiid']) {
         if (!isset($record['userid'])) {
             $record['userid'] = $wiki->wikimode == 'individual' ? $USER->id : 0;
         }
         if ($subwiki = wiki_get_subwiki_by_group($record['wikiid'], $record['group'], $record['userid'])) {
             $record['subwikiid'] = $subwiki->id;
         } else {
             $record['subwikiid'] = wiki_add_subwiki($record['wikiid'], $record['group'], $record['userid']);
         }
     }
     if ($wikipage = wiki_get_page_by_title($record['subwikiid'], $record['title'])) {
         $rv = wiki_save_page($wikipage, $record['content'], $USER->id);
         return $rv['page'];
     }
     $pageid = wiki_create_page($record['subwikiid'], $record['title'], $record['format'], $USER->id);
     $wikipage = wiki_get_page($pageid);
     $rv = wiki_save_page($wikipage, $record['content'], $USER->id);
     return $rv['page'];
 }

 /**
  * Generates a page in wiki.
  *
  * @param stdClass wiki object returned from create_instance (if known)
  * @param stdClass|array $record data to insert as wiki entry.
  * @return stdClass
  * @throws coding_exception if neither $record->wikiid nor $wiki->id is specified
  */
 public function create_page($wiki, $record = array())
 {
     global $CFG, $USER;
     require_once $CFG->dirroot . '/mod/wiki/locallib.php';
     $this->pagecount++;
     $record = (array) $record + array('title' => 'wiki page ' . $this->pagecount, 'wikiid' => $wiki->id, 'subwikiid' => 0, 'group' => 0, 'content' => 'Wiki page content ' . $this->pagecount, 'format' => $wiki->defaultformat);
     if (empty($record['wikiid']) && empty($record['subwikiid'])) {
         throw new coding_exception('wiki page generator requires either wikiid or subwikiid');
     }
     if (!$record['subwikiid']) {
         if (!isset($record['userid'])) {
             $record['userid'] = $wiki->wikimode == 'individual' ? $USER->id : 0;
         }
         if ($subwiki = wiki_get_subwiki_by_group($record['wikiid'], $record['group'], $record['userid'])) {
             $record['subwikiid'] = $subwiki->id;
         } else {
             $record['subwikiid'] = wiki_add_subwiki($record['wikiid'], $record['group'], $record['userid']);
         }
     }
     $wikipage = wiki_get_page_by_title($record['subwikiid'], $record['title']);
     if (!$wikipage) {
         $pageid = wiki_create_page($record['subwikiid'], $record['title'], $record['format'], $USER->id);
         $wikipage = wiki_get_page($pageid);
     }
     $rv = wiki_save_page($wikipage, $record['content'], $USER->id);
     if (array_key_exists('tags', $record)) {
         $tags = is_array($record['tags']) ? $record['tags'] : preg_split('/,/', $record['tags']);
         if (empty($wiki->cmid)) {
             $cm = get_coursemodule_from_instance('wiki', $wiki->id, isset($wiki->course) ? $wiki->course : 0);
             $wiki->cmid = $cm->id;
         }
         core_tag_tag::set_item_tags('mod_wiki', 'wiki_pages', $wikipage->id, context_module::instance($wiki->cmid), $tags);
     }
     return $rv['page'];
 }

 /**
  * Returns the list of pages from a specific subwiki.
  *
  * @param int $wikiid The wiki instance ID.
  * @param int $groupid The group ID. If not defined, use current group.
  * @param int $userid The user ID. If not defined, use current user.
  * @param array $options Several options like sort by, sort direction, ...
  * @return array Containing a list of warnings and a list of pages.
  * @since Moodle 3.1
  */
 public static function get_subwiki_pages($wikiid, $groupid = -1, $userid = 0, $options = array())
 {
     global $USER, $DB;
     $returnedpages = array();
     $warnings = array();
     $params = self::validate_parameters(self::get_subwiki_pages_parameters(), array('wikiid' => $wikiid, 'groupid' => $groupid, 'userid' => $userid, 'options' => $options));
     // Get wiki instance.
     if (!($wiki = wiki_get_wiki($params['wikiid']))) {
         throw new moodle_exception('incorrectwikiid', 'wiki');
     }
     list($course, $cm) = get_course_and_cm_from_instance($wiki, 'wiki');
     $context = context_module::instance($cm->id);
     self::validate_context($context);
     // Determine group.
     $groupmode = groups_get_activity_groupmode($cm);
     if ($groupmode == NOGROUPS) {
         $groupid = 0;
     } else {
         if ($params['groupid'] == -1) {
             // Use current group.
             $groupid = groups_get_activity_group($cm);
             $groupid = !empty($groupid) ? $groupid : 0;
         } else {
             $groupid = $params['groupid'];
         }
     }
     // Determine user.
     if ($wiki->wikimode == 'collaborative') {
         // Collaborative wikis don't use userid in subwikis.
         $userid = 0;
     } else {
         if (empty($params['userid'])) {
             // Use current user.
             $userid = $USER->id;
         } else {
             $userid = $params['userid'];
         }
     }
     // Get subwiki based on group and user.
     if (!($subwiki = wiki_get_subwiki_by_group($cm->instance, $groupid, $userid))) {
         // The subwiki doesn't exist.
         // Validate if user is valid.
         if ($userid != 0 && $userid != $USER->id && !($user = $DB->get_record('user', array('id' => $userid)))) {
             throw new moodle_exception('invaliduserid', 'error');
         }
         // Validate that groupid is valid.
         if ($groupid != 0 && !groups_group_exists($groupid)) {
             throw new moodle_exception('cannotfindgroup', 'error');
         }
         // Valid data but subwiki not found. We'll simulate a subwiki object to check if the user would be able to see it
         // if it existed. If he's able to see it then we'll return an empty array because the subwiki has no pages.
         $subwiki = new stdClass();
         $subwiki->wikiid = $wiki->id;
         $subwiki->userid = $userid;
         $subwiki->groupid = $groupid;
         // Check that the user can view the subwiki. This function checks capabilities.
         if (!wiki_user_can_view($subwiki, $wiki)) {
             throw new moodle_exception('cannotviewpage', 'wiki');
         }
     } else {
         // Check that the user can view the subwiki. This function checks capabilities.
         if (!wiki_user_can_view($subwiki, $wiki)) {
             throw new moodle_exception('cannotviewpage', 'wiki');
         }
         // Set sort param.
         $options = $params['options'];
         if (!empty($options['sortby'])) {
             if ($options['sortdirection'] != 'ASC' && $options['sortdirection'] != 'DESC') {
                 // Invalid sort direction. Use default.
                 $options['sortdirection'] = 'ASC';
             }
             $sort = $options['sortby'] . ' ' . $options['sortdirection'];
         }
         $pages = wiki_get_page_list($subwiki->id, $sort);
         $caneditpages = wiki_user_can_edit($subwiki);
         $firstpage = wiki_get_first_page($subwiki->id);
         foreach ($pages as $page) {
             $retpage = array('id' => $page->id, 'subwikiid' => $page->subwikiid, 'title' => external_format_string($page->title, $context->id), 'timecreated' => $page->timecreated, 'timemodified' => $page->timemodified, 'timerendered' => $page->timerendered, 'userid' => $page->userid, 'pageviews' => $page->pageviews, 'readonly' => $page->readonly, 'caneditpage' => $caneditpages, 'firstpage' => $page->id == $firstpage->id);
             if ($options['includecontent']) {
                 // Refresh page cached content if needed.
                 if ($page->timerendered + WIKI_REFRESH_CACHE_TIME < time()) {
                     if ($content = wiki_refresh_cachedcontent($page)) {
                         $page = $content['page'];
                     }
                 }
                 list($retpage['cachedcontent'], $retpage['contentformat']) = external_format_text($page->cachedcontent, FORMAT_HTML, $context->id, 'mod_wiki', 'attachments', $subwiki->id);
             }
             $returnedpages[] = $retpage;
         }
     }
//.........这里部分代码省略.........