не понятен алгоритм

<?php // rnmessages.php
include_once 'rnheader.php';
 
if (!isset($_SESSION['user']))
    die("<br /><br />You need to login to view this page");
$user = $_SESSION['user'];
 
if (isset($_GET['view'])) $view = sanitizeString($_GET['view']);
else $view = $user;
 
if (isset($_POST['text']))
{
    $text = sanitizeString($_POST['text']);
 
    if ($text != "")
    {
        $pm = substr(sanitizeString($_POST['pm']),0,1);
        $time = time();
        queryMysql("INSERT INTO rnmessages VALUES(NULL,
                   '$user', '$view', '$pm', $time, '$text')");
    }
}
 
if ($view != "")
{
    if ($view == $user)
    {
        $name1 = "Your";
        $name2 = "Your";
    }
    else
    {
        $name1 = "<a href='rnmembers.php?view=$view'>$view</a>'s";
        $name2 = "$view's";
    }
 
    echo "<h3>$name1 Messages</h3>";
    showProfile($view);
    
    echo <<<_END
<form method='post' action='rnmessages.php?view=$view'>
Type here to leave a message:<br />
<textarea name='text' cols='40' rows='3'></textarea><br />
Public<input type='radio' name='pm' value='0' checked='checked' />
Private<input type='radio' name='pm' value='1' />
<input type='submit' value='Post Message' /></form>
_END;
 
    if (isset($_GET['erase']))
    {
        $erase = sanitizeString($_GET['erase']);
        queryMysql("DELETE FROM rnmessages WHERE id=$erase
                    AND recip='$user'");
    }
    
    $query = "SELECT * FROM rnmessages WHERE recip='$view'
              ORDER BY time DESC";
    $result = queryMysql($query);
    $num = mysql_num_rows($result);
    
    for ($j = 0 ; $j < $num ; ++$j)
    {
        $row = mysql_fetch_row($result);
 
        if ($row[3] == 0 ||
            $row[1] == $user ||
            $row[2] == $user)
        {
            echo date('M jS \'y g:sa:', $row[4]);
            echo " <a href='rnmessages.php?";
            echo "view=$row[1]'>$row[1]</a> ";
 
            if ($row[3] == 0)
            {
                echo "wrote: &quot;$row[5]&quot; ";
            }
            else
            {
                echo "whispered: <i><font
                color='#006600'>&quot;$row[5]&quot;</font></i> ";
            }
 
            if ($row[2] == $user)
            {
                echo "[<a href='rnmessages.php?view=$view";
                echo "&erase=$row[0]'>erase</a>]";
            }
            echo "<br>";
        }
    }
}
 
if (!$num) echo "<li>No messages yet</li><br />";
 
echo "<br><a href='rnmessages.php?view=$view'>Refresh messages</a>";
echo " | <a href='rnfriends.php?view=$view'>View $name2 friends</a>";
?>