<?php  // $Id$

/** jsupdated.php - notes by Martin Langhoff <martin@catalyst.net.nz>
 ** 
 ** This is an alternative version of jsupdate.php that acts
 ** as a long-running daemon. It will feed/stall/feed JS updates
 ** to the client. From the module configuration select "Stream"
 ** updates.
 ** 
 ** The client connection is not forever though. Once we reach 
 ** CHAT_MAX_CLIENT_UPDATES, it will force the client to re-fetch it. 
 ** 
 ** This buys us all the benefits that chatd has, minus the setup,
 ** as we are using apache to do the daemon handling.
 **
 **/


    define('CHAT_MAX_CLIENT_UPDATES', 1000);
    $nomoodlecookie = true;     // Session not needed!

    require('../../../config.php');
    require('../lib.php');

    // we are going to run for a long time
    // avoid being terminated by php
    @set_time_limit(0);

    $chat_sid      = required_param('chat_sid',          PARAM_ALPHANUM);
    $chat_lasttime = optional_param('chat_lasttime',  0, PARAM_INT);
    $chat_lastrow  = optional_param('chat_lastrow',   1, PARAM_INT);
    $chat_lastid   = optional_param('chat_lastid',    0, PARAM_INT);

    if (!$chatuser = get_record('chat_users', 'sid', $chat_sid)) {
        error('Not logged in!');
    }

    //Get the minimal course
    if (!$course = get_record('course','id',$chatuser->course,'','','','','id,theme,lang')) {
        error('incorrect course id');
    }

    //Get the user theme and enough info to be used in chat_format_message() which passes it along to
    // chat_format_message_manually() -- and only id and timezone are used.
    if (!$USER = get_record('user','id',$chatuser->userid)) { // no optimisation here, it would break again in future!
        error('User does not exist!');
    }
    $USER->description = '';

    //Setup course, lang and theme
    course_setup($course);

    // force deleting of timed out users if there is a silence in room or just entering
    if ((time() - $chat_lasttime) > $CFG->chat_old_ping) {
        // must be done before chat_get_latest_message!!!
        chat_delete_old_users();
    }

    //
    // Time to send headers, and lay out the basic JS updater page
    //
    header('Expires: Sun, 28 Dec 1997 09:32:45 GMT');
    header('Last-Modified: '.gmdate('D, d M Y H:i:s').' GMT');
    header('Cache-Control: no-cache, must-revalidate');
    header('Pragma: no-cache');
    header('Content-Type: text/html; charset=utf-8');

    /// required stylesheets
    $stylesheetshtml = '';
    foreach ($CFG->stylesheets as $stylesheet) {
        $stylesheetshtml .= '<link rel="stylesheet" type="text/css" href="'.$stylesheet.'" />';
    }

?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
    <head>
        <meta http-equiv="content-type" content="text/html; charset=utf-8" />
        <script type="text/javascript">
        //<![CDATA[
        function safari_refresh() {
            self.location.href= '<?php echo $refreshurl;?>';
        }
        var issafari = false;
        if(window.devicePixelRatio){
            issafari = true;
            setTimeout('safari_refresh()', <?php echo $CFG->chat_refresh_room*1000;?>);
        }
        if (parent.msg.document.getElementById("msgStarted") == null) {
            parent.msg.document.close();
            parent.msg.document.open("text/html","replace");
            parent.msg.document.write("<!DOCTYPE html PUBLIC \"-//W3C//DTD XHTML 1.0 Transitional//EN\" \"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd\">");
            parent.msg.document.write("<html><head>");
            parent.msg.document.write("<meta http-equiv=\"content-type\" content=\"text/html; charset=utf-8\" />");
            parent.msg.document.write("<base target=\"_blank\" />");
            parent.msg.document.write("<?php echo addslashes_js($stylesheetshtml) ?>");
            parent.msg.document.write("</head><body class=\"mod-chat-gui_header_js course-<?php echo $chatuser->course ?>\" id=\"mod-chat-gui_header_js-jsupdate\"><div style=\"display: none\" id=\"msgStarted\">&nbsp;</div>");
        }
        //]]>
        </script>
   </head>
   <body>

<?php

    // Ensure the HTML head makes it out there
    echo $CHAT_DUMMY_DATA;
    @ob_end_flush();   

    for ($n=0; $n <= CHAT_MAX_CLIENT_UPDATES; $n++) { 
        
        // ping first so we can later shortcut as needed.
        $chatuser->lastping = time();
        set_field('chat_users', 'lastping', $chatuser->lastping, 'id', $chatuser->id  );

        if ($message = chat_get_latest_message($chatuser->chatid, $chatuser->groupid)) {
            $chat_newlasttime = $message->timestamp;
            $chat_newlastid   = $message->id;
        } else {
            $chat_newlasttime = 0;
            $chat_newlastid   = 0;
            print " \n";
            print $CHAT_DUMMY_DATA;
            @ob_end_flush();
            sleep($CFG->chat_refresh_room);
            continue;
        }

        $timenow    = time();
                
                
        $groupselect = $chatuser->groupid ? " AND (groupid='".$chatuser->groupid."' OR groupid='0') " : "";

        $newcriteria = '';
        if ($chat_lastid > 0) {
            $newcriteria = "id > $chat_lastid";
        } else {
            if ($chat_lasttime == 0) { //display some previous messages
                $chat_lasttime = $timenow - $CFG->chat_old_ping; //TO DO - any better value??
            }
            $newcriteria = "timestamp > $chat_lasttime";
        }
        
        $messages = get_records_select("chat_messages",
                                       "chatid = '$chatuser->chatid' AND $newcriteria $groupselect",
                                       "timestamp ASC");
        
        if ($messages) {
            $num = count($messages);
        } else {
            print " \n";
            print $CHAT_DUMMY_DATA;
            @ob_end_flush();
            sleep($CFG->chat_refresh_room);
            continue;
            $num = 0;
        }

        print '<script type="text/javascript">' . "\n";
        print "//<![CDATA[\n\n"; 

        $chat_newrow = ($chat_lastrow + $num) % 2;

        $refreshusers = false;
        $us = array ();
        if (($chat_lasttime != $chat_newlasttime) and $messages) {

            $beep         = false;
            $refreshusers = false; 
            foreach ($messages as $message) {
                $chat_lastrow = ($chat_lastrow + 1) % 2;
                $formatmessage = chat_format_message($message, $chatuser->course, $USER, $chat_lastrow);
                if ($formatmessage->beep) {
                    $beep = true;
                }
                if ($formatmessage->refreshusers) {
                    $refreshusers = true;
                }
                $us[$message->userid] = $timenow - $message->timestamp;
                echo "parent.msg.document.write('".addslashes_js($formatmessage->html )."\\n');\n";

            }
            // from the last message printed...
            // a strange case where lack of closures is useful!
            $chat_lasttime = $message->timestamp;
            $chat_lastid   = $message->id;
        }
                
        if ($refreshusers) {
            echo "if (parent.users.document.anchors[0] != null) {" .
                "parent.users.location.href = parent.users.document.anchors[0].href;}\n";
        } else {
            foreach($us as $uid=>$lastping) {
                $min = (int) ($lastping/60);
                $sec = $lastping - ($min*60);
                $min = $min < 10 ? '0'.$min : $min;
                $sec = $sec < 10 ? '0'.$sec : $sec;
                $idle = $min.':'.$sec;
                echo "if (parent.users.document.getElementById('uidle{$uid}') != null) {".
                        "parent.users.document.getElementById('uidle{$uid}').innerHTML = '$idle';}\n";
            }
        }

        print <<<EOD
        if(parent.input){
            var autoscroll = parent.input.document.getElementById('auto');
            if(parent.msg && autoscroll && autoscroll.checked){
                parent.msg.scroll(1,5000000);
            }
        }
EOD;
        print "//]]>\n";
        print '</script>' . "\n\n";
        if ($beep) {
            print '<embed src="../beep.wav" autostart="true" hidden="true" name="beep" />';
        }
        print $CHAT_DUMMY_DATA;
        @ob_end_flush();
        sleep($CFG->chat_refresh_room);
    } // here ends the for() loop 

    // here & should be written & :-D
    $refreshurl = "{$CFG->wwwroot}/mod/chat/gui_header_js/jsupdated.php?chat_sid=$chat_sid&chat_lasttime=$chat_lasttime&chat_lastrow=$chat_newrow&chat_lastid=$chat_lastid"; 
    print '<script type="text/javascript">' . "\n";
    print "//<![CDATA[ \n\n"; 
    print "location.href = '$refreshurl';\n";
    print "//]]>\n";
    print '</script>' . "\n\n";

?>

    </body>
</html>
