mod/chat/lib.php

   1 <?php
   2
   3 // This file is part of Moodle - http://moodle.org/
   4 //
   5 // Moodle is free software: you can redistribute it and/or modify
   6 // it under the terms of the GNU General Public License as published by
   7 // the Free Software Foundation, either version 3 of the License, or
   8 // (at your option) any later version.
   9 //
  10 // Moodle is distributed in the hope that it will be useful,
  11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 // GNU General Public License for more details.
  14 //
  15 // You should have received a copy of the GNU General Public License
  16 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  17
  18 /**
  19  * Library of functions and constants for module chat
  20  *
  21  * @package   mod-chat
  22  * @copyright 1999 onwards Martin Dougiamas  {@link http://moodle.com}
  23  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  24  */
  25
  26 require_once($CFG->dirroot.'/calendar/lib.php');
  27
  28 // The HTML head for the message window to start with (<!-- nix --> is used to get some browsers starting with output
  29 global $CHAT_HTMLHEAD;
  30 $CHAT_HTMLHEAD = "<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.0 Transitional//EN\" \"http://www.w3.org/TR/REC-html40/loose.dtd\"><html><head></head>\n<body>\n\n".padding(200);
  31
  32 // The HTML head for the message window to start with (with js scrolling)
  33 global $CHAT_HTMLHEAD_JS;
  34 $CHAT_HTMLHEAD_JS = <<<EOD
  35 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
  36 <html><head><script type="text/javascript">
  37 //<![CDATA[
  38 function move(){
  39     if (scroll_active)
  40         window.scroll(1,400000);
  41     window.setTimeout("move()",100);
  42 }
  43 var scroll_active = true;
  44 move();
  45 //]]>
  46 </script>
  47 </head>
  48 <body onBlur="scroll_active = true" onFocus="scroll_active = false">
  49 EOD;
  50 global $CHAT_HTMLHEAD_JS;
  51 $CHAT_HTMLHEAD_JS .= padding(200);
  52
  53 // The HTML code for standard empty pages (e.g. if a user was kicked out)
  54 global $CHAT_HTMLHEAD_OUT;
  55 $CHAT_HTMLHEAD_OUT = "<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.0 Transitional//EN\" \"http://www.w3.org/TR/REC-html40/loose.dtd\"><html><head><title>You are out!</title></head><body></body></html>";
  56
  57 // The HTML head for the message input page
  58 global $CHAT_HTMLHEAD_MSGINPUT;
  59 $CHAT_HTMLHEAD_MSGINPUT = "<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.0 Transitional//EN\" \"http://www.w3.org/TR/REC-html40/loose.dtd\"><html><head><title>Message Input</title></head><body>";
  60
  61 // The HTML code for the message input page, with JavaScript
  62 global $CHAT_HTMLHEAD_MSGINPUT_JS;
  63 $CHAT_HTMLHEAD_MSGINPUT_JS = <<<EOD
  64 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
  65 <html>
  66     <head><title>Message Input</title>
  67     <script type="text/javascript">
  68     //<![CDATA[
  69     scroll_active = true;
  70     function empty_field_and_submit(){
  71         document.fdummy.arsc_message.value=document.f.arsc_message.value;
  72         document.fdummy.submit();
  73         document.f.arsc_message.focus();
  74         document.f.arsc_message.select();
  75         return false;
  76     }
  77     //]]>
  78     </script>
  79     </head><body OnLoad="document.f.arsc_message.focus();document.f.arsc_message.select();">;
  80 EOD;
  81
  82 // Dummy data that gets output to the browser as needed, in order to make it show output
  83 global $CHAT_DUMMY_DATA;
  84 $CHAT_DUMMY_DATA = padding(200);
  85
  86 /**
  87  * @param int $n
  88  * @return string
  89  */
  90 function padding($n){
  91     $str = '';
  92     for($i=0; $i<$n; $i++){
  93         $str.="<!-- nix -->\n";
  94     }
  95     return $str;
  96 }
  97
  98 /**
  99  * Given an object containing all the necessary data,
 100  * (defined by the form in mod_form.php) this function
 101  * will create a new instance and return the id number
 102  * of the new instance.
 103  *
 104  * @global object
 105  * @param object $chat
 106  * @return int
 107  */
 108 function chat_add_instance($chat) {
 109     global $DB;
 110
 111     $chat->timemodified = time();
 112
 113     $returnid = $DB->insert_record("chat", $chat);
 114
 115     $event = NULL;
 116     $event->name        = $chat->name;
 117     $event->description = format_module_intro('chat', $chat, $chat->coursemodule);
 118     $event->courseid    = $chat->course;
 119     $event->groupid     = 0;
 120     $event->userid      = 0;
 121     $event->modulename  = 'chat';
 122     $event->instance    = $returnid;
 123     $event->eventtype   = 'chattime';
 124     $event->timestart   = $chat->chattime;
 125     $event->timeduration = 0;
 126
 127     calendar_event::create($event);
 128
 129     return $returnid;
 130 }
 131
 132 /**
 133  * Given an object containing all the necessary data,
 134  * (defined by the form in mod_form.php) this function
 135  * will update an existing instance with new data.
 136  *
 137  * @global object
 138  * @param object $chat
 139  * @return bool
 140  */
 141 function chat_update_instance($chat) {
 142     global $DB;
 143
 144     $chat->timemodified = time();
 145     $chat->id = $chat->instance;
 146
 147
 148     $DB->update_record("chat", $chat);
 149
 150     $event = new stdClass();
 151
 152     if ($event->id = $DB->get_field('event', 'id', array('modulename'=>'chat', 'instance'=>$chat->id))) {
 153
 154         $event->name        = $chat->name;
 155         $event->description = format_module_intro('chat', $chat, $chat->coursemodule);
 156         $event->timestart   = $chat->chattime;
 157
 158         $calendarevent = calendar_event::load($event->id);
 159         $calendarevent->update($event);
 160     }
 161
 162     return true;
 163 }
 164
 165 /**
 166  * Given an ID of an instance of this module,
 167  * this function will permanently delete the instance
 168  * and any data that depends on it.
 169  *
 170  * @global object
 171  * @param int $id
 172  * @return bool
 173  */
 174 function chat_delete_instance($id) {
 175     global $DB;
 176
 177
 178     if (! $chat = $DB->get_record('chat', array('id'=>$id))) {
 179         return false;
 180     }
 181
 182     $result = true;
 183
 184     // Delete any dependent records here
 185
 186     if (! $DB->delete_records('chat', array('id'=>$chat->id))) {
 187         $result = false;
 188     }
 189     if (! $DB->delete_records('chat_messages', array('chatid'=>$chat->id))) {
 190         $result = false;
 191     }
 192     if (! $DB->delete_records('chat_messages_current', array('chatid'=>$chat->id))) {
 193         $result = false;
 194     }
 195     if (! $DB->delete_records('chat_users', array('chatid'=>$chat->id))) {
 196         $result = false;
 197     }
 198
 199     if (! $DB->delete_records('event', array('modulename'=>'chat', 'instance'=>$chat->id))) {
 200         $result = false;
 201     }
 202
 203     return $result;
 204 }
 205
 206 /**
 207  * Return a small object with summary information about what a
 208  * user has done with a given particular instance of this module
 209  * Used for user activity reports.
 210  * <code>
 211  * $return->time = the time they did it
 212  * $return->info = a short text description
 213  * </code>
 214  *
 215  * @param object $course
 216  * @param object $user
 217  * @param object $mod
 218  * @param object $chat
 219  * @return void
 220  */
 221 function chat_user_outline($course, $user, $mod, $chat) {
 222     return NULL;
 223 }
 224
 225 /**
 226  * Print a detailed representation of what a  user has done with
 227  * a given particular instance of this module, for user activity reports.
 228  *
 229  * @param object $course
 230  * @param object $user
 231  * @param object $mod
 232  * @param object $chat
 233  * @return bool
 234  */
 235 function chat_user_complete($course, $user, $mod, $chat) {
 236     return true;
 237 }
 238
 239 /**
 240  * Given a course and a date, prints a summary of all chat rooms past and present
 241  * This function is called from course/lib.php: print_recent_activity()
 242  *
 243  * @global object
 244  * @global object
 245  * @global object
 246  * @param object $course
 247  * @param bool $viewfullnames
 248  * @param int|string $timestart Timestamp
 249  * @return bool
 250  */
 251 function chat_print_recent_activity($course, $viewfullnames, $timestart) {
 252     global $CFG, $USER, $DB, $OUTPUT;
 253
 254     // this is approximate only, but it is really fast ;-)
 255     $timeout = $CFG->chat_old_ping * 10;
 256
 257     if (!$mcms = $DB->get_records_sql("SELECT cm.id, MAX(chm.timestamp) AS lasttime
 258                                          FROM {course_modules} cm
 259                                          JOIN {modules} md        ON md.id = cm.module
 260                                          JOIN {chat} ch           ON ch.id = cm.instance
 261                                          JOIN {chat_messages} chm ON chm.chatid = ch.id
 262                                         WHERE chm.timestamp > ? AND ch.course = ? AND md.name = 'chat'
 263                                      GROUP BY cm.id
 264                                      ORDER BY lasttime ASC", array($timestart, $course->id))) {
 265          return false;
 266     }
 267
 268     $past     = array();
 269     $current  = array();
 270     $modinfo =& get_fast_modinfo($course); // reference needed because we might load the groups
 271
 272     foreach ($mcms as $cmid=>$mcm) {
 273         if (!array_key_exists($cmid, $modinfo->cms)) {
 274             continue;
 275         }
 276         $cm = $modinfo->cms[$cmid];
 277         $cm->lasttime = $mcm->lasttime;
 278         if (!$modinfo->cms[$cm->id]->uservisible) {
 279             continue;
 280         }
 281
 282         if (groups_get_activity_groupmode($cm) != SEPARATEGROUPS
 283          or has_capability('moodle/site:accessallgroups', get_context_instance(CONTEXT_MODULE, $cm->id))) {
 284             if ($timeout > time() - $cm->lasttime) {
 285                 $current[] = $cm;
 286             } else {
 287                 $past[] = $cm;
 288             }
 289
 290             continue;
 291         }
 292
 293         if (is_null($modinfo->groups)) {
 294             $modinfo->groups = groups_get_user_groups($course->id); // load all my groups and cache it in modinfo
 295         }
 296
 297         // verify groups in separate mode
 298         if (!$mygroupids = $modinfo->groups[$cm->groupingid]) {
 299             continue;
 300         }
 301
 302         // ok, last post was not for my group - we have to query db to get last message from one of my groups
 303         // only minor problem is that the order will not be correct
 304         $mygroupids = implode(',', $mygroupids);
 305         $cm->mygroupids = $mygroupids;
 306
 307         if (!$mcm = $DB->get_record_sql("SELECT cm.id, MAX(chm.timestamp) AS lasttime
 308                                            FROM {course_modules} cm
 309                                            JOIN {chat} ch           ON ch.id = cm.instance
 310                                            JOIN {chat_messages_current} chm ON chm.chatid = ch.id
 311                                           WHERE chm.timestamp > ? AND cm.id = ? AND
 312                                                 (chm.groupid IN ($mygroupids) OR chm.groupid = 0)
 313                                        GROUP BY cm.id", array($timestart, $cm->id))) {
 314              continue;
 315         }
 316
 317         $cm->lasttime = $mcm->lasttime;
 318         if ($timeout > time() - $cm->lasttime) {
 319             $current[] = $cm;
 320         } else {
 321             $past[] = $cm;
 322         }
 323     }
 324
 325     if (!$past and !$current) {
 326         return false;
 327     }
 328
 329     $strftimerecent = get_string('strftimerecent');
 330
 331     if ($past) {
 332         echo $OUTPUT->heading(get_string("pastchats", 'chat').':');
 333
 334         foreach ($past as $cm) {
 335             $link = $CFG->wwwroot.'/mod/chat/view.php?id='.$cm->id;
 336             $date = userdate($cm->lasttime, $strftimerecent);
 337             echo '<div class="head"><div class="date">'.$date.'</div></div>';
 338             echo '<div class="info"><a href="'.$link.'">'.format_string($cm->name,true).'</a></div>';
 339         }
 340     }
 341
 342     if ($current) {
 343         echo $OUTPUT->heading(get_string("currentchats", 'chat').':');
 344
 345         $oldest = floor((time()-$CFG->chat_old_ping)/10)*10;  // better db caching
 346
 347         $timeold    = time() - $CFG->chat_old_ping;
 348         $timeold    = floor($timeold/10)*10;  // better db caching
 349         $timeoldext = time() - ($CFG->chat_old_ping*10); // JSless gui_basic needs much longer timeouts
 350         $timeoldext = floor($timeoldext/10)*10;  // better db caching
 351
 352         $params = array('timeold'=>$timeold, 'timeoldext'=>$timeoldext, 'cmid'=>$cm->id);
 353
 354         $timeout = "AND (chu.version<>'basic' AND chu.lastping>:timeold) OR (chu.version='basic' AND chu.lastping>:timeoldext)";
 355
 356         foreach ($current as $cm) {
 357             //count users first
 358             if (isset($cm->mygroupids)) {
 359                 $groupselect = "AND (chu.groupid IN ({$cm->mygroupids}) OR chu.groupid = 0)";
 360             } else {
 361                 $groupselect = "";
 362             }
 363
 364             if (!$users = $DB->get_records_sql("SELECT u.id, u.firstname, u.lastname, u.email, u.picture
 365                                                   FROM {course_modules} cm
 366                                                   JOIN {chat} ch        ON ch.id = cm.instance
 367                                                   JOIN {chat_users} chu ON chu.chatid = ch.id
 368                                                   JOIN {user} u         ON u.id = chu.userid
 369                                                  WHERE cm.id = :cmid $timeout $groupselect
 370                                               GROUP BY u.id, u.firstname, u.lastname, u.email, u.picture", $params)) {
 371             }
 372
 373             $link = $CFG->wwwroot.'/mod/chat/view.php?id='.$cm->id;
 374             $date = userdate($cm->lasttime, $strftimerecent);
 375
 376             echo '<div class="head"><div class="date">'.$date.'</div></div>';
 377             echo '<div class="info"><a href="'.$link.'">'.format_string($cm->name,true).'</a></div>';
 378             echo '<div class="userlist">';
 379             if ($users) {
 380                 echo '<ul>';
 381                     foreach ($users as $user) {
 382                         echo '<li>'.fullname($user, $viewfullnames).'</li>';
 383                     }
 384                 echo '</ul>';
 385             }
 386             echo '</div>';
 387         }
 388     }
 389
 390     return true;
 391 }
 392
 393 /**
 394  * Function to be run periodically according to the moodle cron
 395  * This function searches for things that need to be done, such
 396  * as sending out mail, toggling flags etc ...
 397  *
 398  * @global object
 399  * @return bool
 400  */
 401 function chat_cron () {
 402     global $DB;
 403
 404     chat_update_chat_times();
 405
 406     chat_delete_old_users();
 407
 408     /// Delete old messages with a
 409     /// single SQL query.
 410     $subselect = "SELECT c.keepdays
 411                     FROM {chat} c
 412                    WHERE c.id = {chat_messages}.chatid";
 413
 414     $sql = "DELETE
 415               FROM {chat_messages}
 416              WHERE ($subselect) > 0 AND timestamp < ( ".time()." -($subselect) * 24 * 3600)";
 417
 418     $DB->execute($sql);
 419
 420     $sql = "DELETE
 421               FROM {chat_messages_current}
 422              WHERE timestamp < ( ".time()." - 8 * 3600)";
 423
 424     $DB->execute($sql);
 425
 426     return true;
 427 }
 428
 429 /**
 430  * Returns the users with data in one chat
 431  * (users with records in chat_messages, students)
 432  *
 433  * @todo: deprecated - to be deleted in 2.2
 434  *
 435  * @param int $chatid
 436  * @param int $groupid
 437  * @return array
 438  */
 439 function chat_get_participants($chatid, $groupid=0) {
 440     global $DB;
 441
 442     $params = array('groupid'=>$groupid, 'chatid'=>$chatid);
 443
 444     if ($groupid) {
 445         $groupselect = " AND (c.groupid=:groupid OR c.groupid='0')";
 446     } else {
 447         $groupselect = "";
 448     }
 449
 450     //Get students
 451     $students = $DB->get_records_sql("SELECT DISTINCT u.id, u.id
 452                                         FROM {user} u, {chat_messages} c
 453                                        WHERE c.chatid = :chatid $groupselect
 454                                              AND u.id = c.userid", $params);
 455
 456     //Return students array (it contains an array of unique users)
 457     return ($students);
 458 }
 459
 460 /**
 461  * This standard function will check all instances of this module
 462  * and make sure there are up-to-date events created for each of them.
 463  * If courseid = 0, then every chat event in the site is checked, else
 464  * only chat events belonging to the course specified are checked.
 465  * This function is used, in its new format, by restore_refresh_events()
 466  *
 467  * @global object
 468  * @param int $courseid
 469  * @return bool
 470  */
 471 function chat_refresh_events($courseid = 0) {
 472     global $DB;
 473
 474     if ($courseid) {
 475         if (! $chats = $DB->get_records("chat", array("course"=>$courseid))) {
 476             return true;
 477         }
 478     } else {
 479         if (! $chats = $DB->get_records("chat")) {
 480             return true;
 481         }
 482     }
 483     $moduleid = $DB->get_field('modules', 'id', array('name'=>'chat'));
 484
 485     foreach ($chats as $chat) {
 486         $cm = get_coursemodule_from_id('chat', $chat->id);
 487         $event = new stdClass();
 488         $event->name        = $chat->name;
 489         $event->description = format_module_intro('chat', $chat, $cm->id);
 490         $event->timestart   = $chat->chattime;
 491
 492         if ($event->id = $DB->get_field('event', 'id', array('modulename'=>'chat', 'instance'=>$chat->id))) {
 493             $calendarevent = calendar_event::load($event->id);
 494             $calendarevent->update($event);
 495         } else {
 496             $event->courseid    = $chat->course;
 497             $event->groupid     = 0;
 498             $event->userid      = 0;
 499             $event->modulename  = 'chat';
 500             $event->instance    = $chat->id;
 501             $event->eventtype   = 'chattime';
 502             $event->timeduration = 0;
 503             $event->visible     = $DB->get_field('course_modules', 'visible', array('module'=>$moduleid, 'instance'=>$chat->id));
 504
 505             calendar_event::create($event);
 506         }
 507     }
 508     return true;
 509 }
 510
 511
 512 //////////////////////////////////////////////////////////////////////
 513 /// Functions that require some SQL
 514
 515 /**
 516  * @global object
 517  * @param int $chatid
 518  * @param int $groupid
 519  * @param int $groupingid
 520  * @return array
 521  */
 522 function chat_get_users($chatid, $groupid=0, $groupingid=0) {
 523     global $DB;
 524
 525     $params = array('chatid'=>$chatid, 'groupid'=>$groupid, 'groupingid'=>$groupingid);
 526
 527     if ($groupid) {
 528         $groupselect = " AND (c.groupid=:groupid OR c.groupid='0')";
 529     } else {
 530         $groupselect = "";
 531     }
 532
 533     if (!empty($groupingid)) {
 534         $groupingjoin = "JOIN {groups_members} gm ON u.id = gm.userid
 535                          JOIN {groupings_groups} gg ON gm.groupid = gg.groupid AND gg.groupingid = :groupingid ";
 536
 537     } else {
 538         $groupingjoin = '';
 539     }
 540
 541     $ufields = user_picture::fields('u');
 542     return $DB->get_records_sql("SELECT DISTINCT $ufields, c.lastmessageping, c.firstping
 543                                    FROM {chat_users} c
 544                                    JOIN {user} u ON u.id = c.userid $groupingjoin
 545                                   WHERE c.chatid = :chatid $groupselect
 546                                ORDER BY c.firstping ASC", $params);
 547 }
 548
 549 /**
 550  * @global object
 551  * @param int $chatid
 552  * @param int $groupid
 553  * @return array
 554  */
 555 function chat_get_latest_message($chatid, $groupid=0) {
 556     global $DB;
 557
 558     $params = array('chatid'=>$chatid, 'groupid'=>$groupid);
 559
 560     if ($groupid) {
 561         $groupselect = "AND (groupid=:groupid OR groupid=0)";
 562     } else {
 563         $groupselect = "";
 564     }
 565
 566     $sql = "SELECT *
 567         FROM {chat_messages_current} WHERE chatid = :chatid $groupselect
 568         ORDER BY timestamp DESC";
 569
 570     // return the lastest one message
 571     return $DB->get_record_sql($sql, $params, true);
 572 }
 573
 574
 575 //////////////////////////////////////////////////////////////////////
 576 // login if not already logged in
 577
 578 /**
 579  * login if not already logged in
 580  *
 581  * @global object
 582  * @global object
 583  * @param int $chatid
 584  * @param string $version
 585  * @param int $groupid
 586  * @param object $course
 587  * @return bool|int Returns the chat users sid or false
 588  */
 589 function chat_login_user($chatid, $version, $groupid, $course) {
 590     global $USER, $DB;
 591
 592     if (($version != 'sockets') and $chatuser = $DB->get_record('chat_users', array('chatid'=>$chatid, 'userid'=>$USER->id, 'groupid'=>$groupid))) {
 593         // this will update logged user information
 594         $chatuser->version  = $version;
 595         $chatuser->ip       = $USER->lastip;
 596         $chatuser->lastping = time();
 597         $chatuser->lang     = current_language();
 598
 599         // Sometimes $USER->lastip is not setup properly
 600         // during login. Update with current value if possible
 601         // or provide a dummy value for the db
 602         if (empty($chatuser->ip)) {
 603             $chatuser->ip = getremoteaddr();
 604         }
 605
 606         if (($chatuser->course != $course->id) or ($chatuser->userid != $USER->id)) {
 607             return false;
 608         }
 609         $DB->update_record('chat_users', $chatuser);
 610
 611     } else {
 612         $chatuser = new stdClass();
 613         $chatuser->chatid   = $chatid;
 614         $chatuser->userid   = $USER->id;
 615         $chatuser->groupid  = $groupid;
 616         $chatuser->version  = $version;
 617         $chatuser->ip       = $USER->lastip;
 618         $chatuser->lastping = $chatuser->firstping = $chatuser->lastmessageping = time();
 619         $chatuser->sid      = random_string(32);
 620         $chatuser->course   = $course->id; //caching - needed for current_language too
 621         $chatuser->lang     = current_language(); //caching - to resource intensive to find out later
 622
 623         // Sometimes $USER->lastip is not setup properly
 624         // during login. Update with current value if possible
 625         // or provide a dummy value for the db
 626         if (empty($chatuser->ip)) {
 627             $chatuser->ip = getremoteaddr();
 628         }
 629
 630
 631         $DB->insert_record('chat_users', $chatuser);
 632
 633         if ($version == 'sockets') {
 634             // do not send 'enter' message, chatd will do it
 635         } else {
 636             $message = new stdClass();
 637             $message->chatid    = $chatuser->chatid;
 638             $message->userid    = $chatuser->userid;
 639             $message->groupid   = $groupid;
 640             $message->message   = 'enter';
 641             $message->system    = 1;
 642             $message->timestamp = time();
 643
 644             $DB->insert_record('chat_messages', $message);
 645             $DB->insert_record('chat_messages_current', $message);
 646         }
 647     }
 648
 649     return $chatuser->sid;
 650 }
 651
 652 /**
 653  * Delete the old and in the way
 654  *
 655  * @global object
 656  * @global object
 657  */
 658 function chat_delete_old_users() {
 659 // Delete the old and in the way
 660     global $CFG, $DB;
 661
 662     $timeold = time() - $CFG->chat_old_ping;
 663     $timeoldext = time() - ($CFG->chat_old_ping*10); // JSless gui_basic needs much longer timeouts
 664
 665     $query = "(version<>'basic' AND lastping<?) OR (version='basic' AND lastping<?)";
 666     $params = array($timeold, $timeoldext);
 667
 668     if ($oldusers = $DB->get_records_select('chat_users', $query, $params) ) {
 669         $DB->delete_records_select('chat_users', $query, $params);
 670         foreach ($oldusers as $olduser) {
 671             $message = new stdClass();
 672             $message->chatid    = $olduser->chatid;
 673             $message->userid    = $olduser->userid;
 674             $message->groupid   = $olduser->groupid;
 675             $message->message   = 'exit';
 676             $message->system    = 1;
 677             $message->timestamp = time();
 678
 679             $DB->insert_record('chat_messages', $message);
 680             $DB->insert_record('chat_messages_current', $message);
 681         }
 682     }
 683 }
 684
 685 /**
 686  * Updates chat records so that the next chat time is correct
 687  *
 688  * @global object
 689  * @param int $chatid
 690  * @return void
 691  */
 692 function chat_update_chat_times($chatid=0) {
 693 /// Updates chat records so that the next chat time is correct
 694     global $DB;
 695
 696     $timenow = time();
 697
 698     $params = array('timenow'=>$timenow, 'chatid'=>$chatid);
 699
 700     if ($chatid) {
 701         if (!$chats[] = $DB->get_record_select("chat", "id = :chatid AND chattime <= :timenow AND schedule > 0", $params)) {
 702             return;
 703         }
 704     } else {
 705         if (!$chats = $DB->get_records_select("chat", "chattime <= :timenow AND schedule > 0", $params)) {
 706             return;
 707         }
 708     }
 709
 710     foreach ($chats as $chat) {
 711         switch ($chat->schedule) {
 712             case 1: // Single event - turn off schedule and disable
 713                     $chat->chattime = 0;
 714                     $chat->schedule = 0;
 715                     break;
 716             case 2: // Repeat daily
 717                     while ($chat->chattime <= $timenow) {
 718                         $chat->chattime += 24 * 3600;
 719                     }
 720                     break;
 721             case 3: // Repeat weekly
 722                     while ($chat->chattime <= $timenow) {
 723                         $chat->chattime += 7 * 24 * 3600;
 724                     }
 725                     break;
 726         }
 727         $DB->update_record("chat", $chat);
 728
 729         $event = new stdClass();           // Update calendar too
 730
 731         $cond = "modulename='chat' AND instance = :chatid AND timestart <> :chattime";
 732         $params = array('chattime'=>$chat->chattime, 'chatid'=>$chatid);
 733
 734         if ($event->id = $DB->get_field_select('event', 'id', $cond, $params)) {
 735             $event->timestart   = $chat->chattime;
 736             $calendarevent = calendar_event::load($event->id);
 737             $calendarevent->update($event, false);
 738         }
 739     }
 740 }
 741
 742 /**
 743  * @global object
 744  * @global object
 745  * @param object $message
 746  * @param int $courseid
 747  * @param object $sender
 748  * @param object $currentuser
 749  * @param string $chat_lastrow
 750  * @return bool|string Returns HTML or false
 751  */
 752 function chat_format_message_manually($message, $courseid, $sender, $currentuser, $chat_lastrow=NULL) {
 753     global $CFG, $USER, $OUTPUT;
 754
 755     $output = new stdClass();
 756     $output->beep = false;       // by default
 757     $output->refreshusers = false; // by default
 758
 759     // Use get_user_timezone() to find the correct timezone for displaying this message:
 760     // It's either the current user's timezone or else decided by some Moodle config setting
 761     // First, "reset" $USER->timezone (which could have been set by a previous call to here)
 762     // because otherwise the value for the previous $currentuser will take precedence over $CFG->timezone
 763     $USER->timezone = 99;
 764     $tz = get_user_timezone($currentuser->timezone);
 765
 766     // Before formatting the message time string, set $USER->timezone to the above.
 767     // This will allow dst_offset_on (called by userdate) to work correctly, otherwise the
 768     // message times appear off because DST is not taken into account when it should be.
 769     $USER->timezone = $tz;
 770     $message->strtime = userdate($message->timestamp, get_string('strftimemessage', 'chat'), $tz);
 771
 772     $message->picture = $OUTPUT->user_picture($sender, array('size'=>false, 'courseid'=>$courseid, 'link'=>false));
 773
 774     if ($courseid) {
 775         $message->picture = "<a onclick=\"window.open('$CFG->wwwroot/user/view.php?id=$sender->id&amp;course=$courseid')\" href=\"$CFG->wwwroot/user/view.php?id=$sender->id&amp;course=$courseid\">$message->picture</a>";
 776     }
 777
 778     //Calculate the row class
 779     if ($chat_lastrow !== NULL) {
 780         $rowclass = ' class="r'.$chat_lastrow.'" ';
 781     } else {
 782         $rowclass = '';
 783     }
 784
 785     // Start processing the message
 786
 787     if(!empty($message->system)) {
 788         // System event
 789         $output->text = $message->strtime.': '.get_string('message'.$message->message, 'chat', fullname($sender));
 790         $output->html  = '<table class="chat-event"><tr'.$rowclass.'><td class="picture">'.$message->picture.'</td><td class="text">';
 791         $output->html .= '<span class="event">'.$output->text.'</span></td></tr></table>';
 792         $output->basic = '<dl><dt class="event">'.$message->strtime.': '.get_string('message'.$message->message, 'chat', fullname($sender)).'</dt></dl>';
 793
 794         if($message->message == 'exit' or $message->message == 'enter') {
 795             $output->refreshusers = true; //force user panel refresh ASAP
 796         }
 797         return $output;
 798     }
 799
 800     // It's not a system event
 801
 802     $text = $message->message;
 803
 804     /// Parse the text to clean and filter it
 805
 806     $options = new stdClass();
 807     $options->para = false;
 808     $text = format_text($text, FORMAT_MOODLE, $options, $courseid);
 809
 810     // And now check for special cases
 811     $special = false;
 812
 813     if (substr($text, 0, 5) == 'beep ') {
 814         /// It's a beep!
 815         $special = true;
 816         $beepwho = trim(substr($text, 5));
 817
 818         if ($beepwho == 'all') {   // everyone
 819             $outinfo = $message->strtime.': '.get_string('messagebeepseveryone', 'chat', fullname($sender));
 820             $outmain = '';
 821             $output->beep = true;  // (eventually this should be set to
 822                                    //  to a filename uploaded by the user)
 823
 824         } else if ($beepwho == $currentuser->id) {  // current user
 825             $outinfo = $message->strtime.': '.get_string('messagebeepsyou', 'chat', fullname($sender));
 826             $outmain = '';
 827             $output->beep = true;
 828
 829         } else {  //something is not caught?
 830             return false;
 831         }
 832     } else if (substr($text, 0, 1) == '/') {     /// It's a user command
 833         // support some IRC commands
 834         $pattern = '#(^\/)(\w+).*#';
 835         preg_match($pattern, trim($text), $matches);
 836         $command = $matches[2];
 837         switch ($command){
 838         case 'me':
 839             $special = true;
 840             $outinfo = $message->strtime;
 841             $outmain = '*** <b>'.$sender->firstname.' '.substr($text, 4).'</b>';
 842             break;
 843         }
 844     } elseif (substr($text, 0, 2) == 'To') {
 845         $pattern = '#To[[:space:]](.*):(.*)#';
 846         preg_match($pattern, trim($text), $matches);
 847         $special = true;
 848         $outinfo = $message->strtime;
 849         $outmain = $sender->firstname.' '.get_string('saidto', 'chat').' <i>'.$matches[1].'</i>: '.$matches[2];
 850     }
 851
 852     if(!$special) {
 853         $outinfo = $message->strtime.' '.$sender->firstname;
 854         $outmain = $text;
 855     }
 856
 857     /// Format the message as a small table
 858
 859     $output->text  = strip_tags($outinfo.': '.$outmain);
 860
 861     $output->html  = "<table class=\"chat-message\"><tr$rowclass><td class=\"picture\" valign=\"top\">$message->picture</td><td class=\"text\">";
 862     $output->html .= "<span class=\"title\">$outinfo</span>";
 863     if ($outmain) {
 864         $output->html .= ": $outmain";
 865         $output->basic = '<dl><dt class="title">'.$outinfo.':</dt><dd class="text">'.$outmain.'</dd></dl>';
 866     } else {
 867         $output->basic = '<dl><dt class="title">'.$outinfo.'</dt></dl>';
 868     }
 869     $output->html .= "</td></tr></table>";
 870     return $output;
 871 }
 872
 873 /**
 874  * @global object
 875  * @param object $message
 876  * @param int $courseid
 877  * @param object $currentuser
 878  * @param string $chat_lastrow
 879  * @return bool|string Returns HTML or false
 880  */
 881 function chat_format_message($message, $courseid, $currentuser, $chat_lastrow=NULL) {
 882 /// Given a message object full of information, this function
 883 /// formats it appropriately into text and html, then
 884 /// returns the formatted data.
 885     global $DB;
 886
 887     static $users;     // Cache user lookups
 888
 889     if (isset($users[$message->userid])) {
 890         $user = $users[$message->userid];
 891     } else if ($user = $DB->get_record('user', array('id'=>$message->userid), user_picture::fields())) {
 892         $users[$message->userid] = $user;
 893     } else {
 894         return NULL;
 895     }
 896     return chat_format_message_manually($message, $courseid, $user, $currentuser, $chat_lastrow);
 897 }
 898
 899 /**
 900  * @global object
 901  * @param object $message
 902  * @param int $courseid
 903  * @param object $currentuser
 904  * @param string $chat_lastrow
 905  * @return bool|string Returns HTML or false
 906  */
 907 function chat_format_message_theme ($message, $courseid, $currentuser, $theme = 'bubble') {
 908     global $CFG, $USER, $OUTPUT, $COURSE, $DB;
 909
 910     static $users;     // Cache user lookups
 911
 912     $result = new stdClass();
 913
 914     if (file_exists($CFG->dirroot . '/mod/chat/gui_ajax/theme/'.$theme.'/config.php')) {
 915         include($CFG->dirroot . '/mod/chat/gui_ajax/theme/'.$theme.'/config.php');
 916     }
 917
 918     if (isset($users[$message->userid])) {
 919         $sender = $users[$message->userid];
 920     } else if ($sender = $DB->get_record('user', array('id'=>$message->userid), user_picture::fields())) {
 921         $users[$message->userid] = $sender;
 922     } else {
 923         return NULL;
 924     }
 925
 926     $USER->timezone = 99;
 927     $tz = get_user_timezone($currentuser->timezone);
 928     $USER->timezone = $tz;
 929
 930     if (empty($courseid)) {
 931         $courseid = $COURSE->id;
 932     }
 933
 934     $message->strtime = userdate($message->timestamp, get_string('strftimemessage', 'chat'), $tz);
 935     $message->picture = $OUTPUT->user_picture($sender, array('courseid'=>$courseid));
 936
 937     $message->picture = "<a target='_blank' href=\"$CFG->wwwroot/user/view.php?id=$sender->id&amp;course=$courseid\">$message->picture</a>";
 938
 939     // Start processing the message
 940     if(!empty($message->system)) {
 941         $result->type = 'system';
 942
 943         $userlink = new moodle_url('/user/view.php', array('id'=>$message->userid,'course'=>$courseid));
 944
 945         $patterns = array();
 946         $replacements = array();
 947         $patterns[] = '___senderprofile___';
 948         $patterns[] = '___sender___';
 949         $patterns[] = '___time___';
 950         $patterns[] = '___event___';
 951         $replacements[] = $CFG->wwwroot.'/user/view.php?id='.$sender->id.'&amp;course='.$courseid;
 952         $replacements[] = fullname($sender);
 953         $replacements[] = $message->strtime;
 954         $replacements[] = get_string('message'.$message->message, 'chat', fullname($sender));
 955         $result->html = str_replace($patterns, $replacements, $chattheme_cfg->event_message);
 956         return $result;
 957     }
 958
 959     // It's not a system event
 960     $text = $message->message;
 961
 962     /// Parse the text to clean and filter it
 963     $options = new stdClass();
 964     $options->para = false;
 965     $text = format_text($text, FORMAT_MOODLE, $options, $courseid);
 966
 967     // And now check for special cases
 968     $special = false;
 969     $outtime = $message->strtime;
 970
 971     if (substr($text, 0, 5) == 'beep ') {
 972         $special = true;
 973         /// It's a beep!
 974         $result->type = 'beep';
 975         $beepwho = trim(substr($text, 5));
 976
 977         if ($beepwho == 'all') {   // everyone
 978             $outmain =  get_string('messagebeepseveryone', 'chat', fullname($sender));
 979         } else if ($beepwho == $currentuser->id) {  // current user
 980             $outmain = get_string('messagebeepsyou', 'chat', fullname($sender));
 981         } else if ($sender->id == $currentuser->id) {  //something is not caught?
 982
 983             $receiver = $DB->get_record('user', array('id'=>$beepwho), 'id,picture,firstname,lastname');
 984             $outmain = get_string('messageyoubeep', 'chat', fullname($receiver));
 985         }
 986     } else if (substr($text, 0, 1) == '/') {     /// It's a user command
 987         $special = true;
 988         $result->type = 'command';
 989         // support some IRC commands
 990         $pattern = '#(^\/)(\w+).*#';
 991         preg_match($pattern, trim($text), $matches);
 992         $command = $matches[2];
 993         $special = true;
 994         switch ($command){
 995         case 'me':
 996             $outmain = '*** <b>'.$sender->firstname.' '.substr($text, 4).'</b>';
 997             break;
 998         }
 999     } elseif (substr($text, 0, 2) == 'To') {
1000         $special = true;
1001         $result->type = 'dialogue';
1002         $pattern = '#To[[:space:]](.*):(.*)#';
1003         preg_match($pattern, trim($text), $matches);
1004         $special = true;
1005         $outmain = $sender->firstname.' <b>'.get_string('saidto', 'chat').'</b> <i>'.$matches[1].'</i>: '.$matches[2];
1006     }
1007
1008     if(!$special) {
1009         $outmain = $text;
1010     }
1011
1012     $result->text = strip_tags($outtime.': '.$outmain);
1013
1014     $ismymessage = '';
1015     $rightalign = '';
1016     if ($sender->id == $USER->id) {
1017         $ismymessage = ' class="mymessage"';
1018         $rightalign = ' align="right"';
1019     }
1020     $patterns = array();
1021     $replacements = array();
1022     $patterns[] = '___avatar___';
1023     $patterns[] = '___sender___';
1024     $patterns[] = '___senderprofile___';
1025     $patterns[] = '___time___';
1026     $patterns[] = '___message___';
1027     $patterns[] = '___mymessageclass___';
1028     $patterns[] = '___tablealign___';
1029     $replacements[] = $message->picture;
1030     $replacements[] = fullname($sender);
1031     $replacements[] = $CFG->wwwroot.'/user/view.php?id='.$sender->id.'&amp;course='.$courseid;
1032     $replacements[] = $outtime;
1033     $replacements[] = $outmain;
1034     $replacements[] = $ismymessage;
1035     $replacements[] = $rightalign;
1036     if (!empty($chattheme_cfg->avatar) and !empty($chattheme_cfg->align)) {
1037         if (!empty($ismymessage)) {
1038             $result->html = str_replace($patterns, $replacements, $chattheme_cfg->user_message_right);
1039         } else {
1040             $result->html = str_replace($patterns, $replacements, $chattheme_cfg->user_message_left);
1041         }
1042     } else {
1043         $result->html = str_replace($patterns, $replacements, $chattheme_cfg->user_message);
1044     }
1045
1046     return $result;
1047 }
1048
1049
1050 /**
1051  * @global object $DB
1052  * @global object $CFG
1053  * @global object $COURSE
1054  * @global object $OUTPUT
1055  * @param object $users
1056  * @param object $course
1057  * @return array return formatted user list
1058  */
1059 function chat_format_userlist($users, $course) {
1060     global $CFG, $DB, $COURSE, $OUTPUT;
1061     $result = array();
1062     foreach($users as $user){
1063         $item = array();
1064         $item['name'] = fullname($user);
1065         $item['url'] = $CFG->wwwroot.'/user/view.php?id='.$user->id.'&amp;course='.$course->id;
1066         $item['picture'] = $OUTPUT->user_picture($user);
1067         $item['id'] = $user->id;
1068         $result[] = $item;
1069     }
1070     return $result;
1071 }
1072
1073 /**
1074  * Print json format error
1075  * @param string $level
1076  * @param string $msg
1077  */
1078 function chat_print_error($level, $msg) {
1079     header('Content-Length: ' . ob_get_length() );
1080     $error = new stdClass();
1081     $error->level = $level;
1082     $error->msg   = $msg;
1083     $response['error'] = $error;
1084     echo json_encode($response);
1085     ob_end_flush();
1086     exit;
1087 }
1088
1089 /**
1090  * @return array
1091  */
1092 function chat_get_view_actions() {
1093     return array('view','view all','report');
1094 }
1095
1096 /**
1097  * @return array
1098  */
1099 function chat_get_post_actions() {
1100     return array('talk');
1101 }
1102
1103 /**
1104  * @global object
1105  * @global object
1106  * @param array $courses
1107  * @param array $htmlarray Passed by reference
1108  */
1109 function chat_print_overview($courses, &$htmlarray) {
1110     global $USER, $CFG;
1111
1112     if (empty($courses) || !is_array($courses) || count($courses) == 0) {
1113         return array();
1114     }
1115
1116     if (!$chats = get_all_instances_in_courses('chat',$courses)) {
1117         return;
1118     }
1119
1120     $strchat = get_string('modulename', 'chat');
1121     $strnextsession  = get_string('nextsession', 'chat');
1122
1123     foreach ($chats as $chat) {
1124         if ($chat->chattime and $chat->schedule) {  // A chat is scheduled
1125             $str = '<div class="chat overview"><div class="name">'.
1126                    $strchat.': <a '.($chat->visible?'':' class="dimmed"').
1127                    ' href="'.$CFG->wwwroot.'/mod/chat/view.php?id='.$chat->coursemodule.'">'.
1128                    $chat->name.'</a></div>';
1129             $str .= '<div class="info">'.$strnextsession.': '.userdate($chat->chattime).'</div></div>';
1130
1131             if (empty($htmlarray[$chat->course]['chat'])) {
1132                 $htmlarray[$chat->course]['chat'] = $str;
1133             } else {
1134                 $htmlarray[$chat->course]['chat'] .= $str;
1135             }
1136         }
1137     }
1138 }
1139
1140
1141 /**
1142  * Implementation of the function for printing the form elements that control
1143  * whether the course reset functionality affects the chat.
1144  *
1145  * @param object $mform form passed by reference
1146  */
1147 function chat_reset_course_form_definition(&$mform) {
1148     $mform->addElement('header', 'chatheader', get_string('modulenameplural', 'chat'));
1149     $mform->addElement('advcheckbox', 'reset_chat', get_string('removemessages','chat'));
1150 }
1151
1152 /**
1153  * Course reset form defaults.
1154  *
1155  * @param object $course
1156  * @return array
1157  */
1158 function chat_reset_course_form_defaults($course) {
1159     return array('reset_chat'=>1);
1160 }
1161
1162 /**
1163  * Actual implementation of the reset course functionality, delete all the
1164  * chat messages for course $data->courseid.
1165  *
1166  * @global object
1167  * @global object
1168  * @param object $data the data submitted from the reset course.
1169  * @return array status array
1170  */
1171 function chat_reset_userdata($data) {
1172     global $CFG, $DB;
1173
1174     $componentstr = get_string('modulenameplural', 'chat');
1175     $status = array();
1176
1177     if (!empty($data->reset_chat)) {
1178         $chatessql = "SELECT ch.id
1179                         FROM {chat} ch
1180                        WHERE ch.course=?";
1181         $params = array($data->courseid);
1182
1183         $DB->delete_records_select('chat_messages', "chatid IN ($chatessql)", $params);
1184         $DB->delete_records_select('chat_messages_current', "chatid IN ($chatessql)", $params);
1185         $DB->delete_records_select('chat_users', "chatid IN ($chatessql)", $params);
1186         $status[] = array('component'=>$componentstr, 'item'=>get_string('removemessages', 'chat'), 'error'=>false);
1187     }
1188
1189     /// updating dates - shift may be negative too
1190     if ($data->timeshift) {
1191         shift_course_mod_dates('chat', array('chattime'), $data->timeshift, $data->courseid);
1192         $status[] = array('component'=>$componentstr, 'item'=>get_string('datechanged'), 'error'=>false);
1193     }
1194
1195     return $status;
1196 }
1197
1198 /**
1199  * Returns all other caps used in module
1200  *
1201  * @return array
1202  */
1203 function chat_get_extra_capabilities() {
1204     return array('moodle/site:accessallgroups', 'moodle/site:viewfullnames');
1205 }
1206
1207
1208 /**
1209  * @param string $feature FEATURE_xx constant for requested feature
1210  * @return mixed True if module supports feature, null if doesn't know
1211  */
1212 function chat_supports($feature) {
1213     switch($feature) {
1214         case FEATURE_GROUPS:                  return true;
1215         case FEATURE_GROUPINGS:               return true;
1216         case FEATURE_GROUPMEMBERSONLY:        return true;
1217         case FEATURE_MOD_INTRO:               return true;
1218         case FEATURE_BACKUP_MOODLE2:          return true;
1219         case FEATURE_COMPLETION_TRACKS_VIEWS: return true;
1220         case FEATURE_GRADE_HAS_GRADE:         return false;
1221         case FEATURE_GRADE_OUTCOMES:          return true;
1222
1223         default: return null;
1224     }
1225 }
1226
1227 function chat_extend_navigation($navigation, $course, $module, $cm) {
1228     global $CFG, $USER, $PAGE, $OUTPUT;
1229
1230     $currentgroup = groups_get_activity_group($cm, true);
1231
1232     if (has_capability('mod/chat:chat', get_context_instance(CONTEXT_MODULE, $cm->id))) {
1233         $strenterchat    = get_string('enterchat', 'chat');
1234
1235         $target = $CFG->wwwroot.'/mod/chat/';
1236         $params = array('id'=>$cm->instance);
1237
1238         if ($currentgroup) {
1239             $params['groupid'] = $currentgroup;
1240         }
1241
1242         $links = array();
1243
1244         // If user is using screenreader, display gui_basic gui link only
1245         if (empty($USER->screenreader)) {
1246             $url = new moodle_url($target.'gui_'.$CFG->chat_method.'/index.php', $params);
1247             $action = new popup_action('click', $url, 'chat'.$course->id.$cm->instance.$currentgroup, array('height' => 500, 'width' => 700));
1248             $links[] = new action_link($url, $strenterchat, $action);
1249         }
1250
1251         $url = new moodle_url($target.'gui_basic/index.php', $params);
1252         $action = new popup_action('click', $url, 'chat'.$course->id.$cm->instance.$currentgroup, array('height' => 500, 'width' => 700));
1253         $links[] = new action_link($url, get_string('noframesjs', 'message'), $action);
1254
1255         foreach ($links as $link) {
1256             $navigation->add($link->text, $link, navigation_node::TYPE_SETTING, null ,null, new pix_icon('c/group' , ''));
1257         }
1258     }
1259
1260     $chatusers = chat_get_users($cm->instance, $currentgroup, $cm->groupingid);
1261     if (is_array($chatusers) && count($chatusers)>0) {
1262         $users = $navigation->add(get_string('currentusers', 'chat'));
1263         foreach ($chatusers as $chatuser) {
1264             $userlink = new moodle_url('/user/view.php', array('id'=>$chatuser->id,'course'=>$course->id));
1265             $users->add(fullname($chatuser).' '.format_time(time() - $chatuser->lastmessageping), $userlink, navigation_node::TYPE_USER, null, null, new pix_icon('c/user', ''));
1266         }
1267     }
1268 }
1269
1270 /**
1271  * Adds module specific settings to the settings block
1272  *
1273  * @param settings_navigation $settings The settings navigation object
1274  * @param navigation_node $chatnode The node to add module settings to
1275  */
1276 function chat_extend_settings_navigation(settings_navigation $settings, navigation_node $chatnode) {
1277     global $DB, $PAGE, $USER;
1278     $chat = $DB->get_record("chat", array("id" => $PAGE->cm->instance));
1279
1280     if ($chat->chattime && $chat->schedule) {
1281         $nextsessionnode = $chatnode->add(get_string('nextsession', 'chat').': '.userdate($chat->chattime).' ('.usertimezone($USER->timezone));
1282         $nextsessionnode->add_class('note');
1283     }
1284
1285     $currentgroup = groups_get_activity_group($PAGE->cm, true);
1286     if ($currentgroup) {
1287         $groupselect = " AND groupid = '$currentgroup'";
1288     } else {
1289         $groupselect = '';
1290     }
1291
1292     if ($chat->studentlogs || has_capability('mod/chat:readlog',$PAGE->cm->context)) {
1293         if ($DB->get_records_select('chat_messages', "chatid = ? $groupselect", array($chat->id))) {
1294             $chatnode->add(get_string('viewreport', 'chat'), new moodle_url('/mod/chat/report.php', array('id'=>$PAGE->cm->id)));
1295         }
1296     }
1297 }
1298
1299 /**
1300  * user logout event handler
1301  *
1302  * @param object $user full $USER object
1303  */
1304 function chat_user_logout($user) {
1305     global $DB;
1306     $DB->delete_records('chat_users', array('userid'=>$user->id));
1307 }
1308
1309 /**
1310  * Return a list of page types
1311  * @param string $pagetype current page type
1312  * @param stdClass $parentcontext Block's parent context
1313  * @param stdClass $currentcontext Current context of block
1314  */
1315 function chat_page_type_list($pagetype, $parentcontext, $currentcontext) {
1316     $module_pagetype = array('mod-chat-*'=>get_string('page-mod-chat-x', 'chat'));
1317     return $module_pagetype;
1318 }