How to implement template logic in PHP

Having my first attempt with PHP templates and i'm a bit confused separating business with presentation logic. I've choosen Dwoo as my template engine as you will see on the example below but my question is independent of Dwoo. I see that what im doing isn't a good logic, it'll confuse the designer and it doesn't really separates PHP/HTML. I can't think any other way of doing it so please if anyone have the time explain me a bit.

Cheers.

PHP Code

$trans = translation('LABEL');  

// Load Template Engine

$dwoo = new Dwoo();
   $dwooTpl = new Dwoo_Template_File('tpl/label.tpl.html');
   $dwooData = new Dwoo_Data();
   $dwooData->assign('title','Page Title');

if(!isset($_SESSION['logged'])){
    $dwooData->assign('logged',0);
    $dwoo->output($dwooTpl,$dwooData);
}else{
    $userID = $_SESSION['userID'];
    if (!isset($_POST['add'])){
        $sql = "SELECT labelName
                FROM label
                WHERE userID = $userID";
        $rs = mysql_query($sql) or die('Can\'t get label'. mysql_error());
        if(mysql_num_rows($rs)){
            while ($row = mysql_fetch_object($rs)){
                $labels[] =  $row->labelName;
            }
            $dwooData->assign('labels',$labels);
        }

    $dwooData->assign('logged',1);
    $dwooData->assign('addLabel',0);
    $dwoo->output($dwooTpl,$dwooData);

}else{

    $labelName = mysql_real_escape_string($_POST['labelName']);
    $labelName = trim($labelName);
        if(strlen($labelName) < 1)
        {
            $dwooData->assign('ERR1','Label Name is not valid.
                  You must enter at least 1 letter as Label开发者_如何学Go name.');
        }else{
            $sql = "SELECT labelName
                    FROM label
                    WHERE userID = '$userID'
                    AND labelName = '$labelName'";
            $rs = mysql_query($sql) or die('Can\'t get label '. mysql_error());
            if(mysql_num_rows($rs)){
               $dwooData->assign('ERR2',"Label '<strong>$labelName</strong>' already exists.");

            }else{
                $sql = "INSERT INTO label
                        VALUES('','$userID','$labelName')";
                mysql_query($sql) or die('Can\'t insert Label '. mysql_error());
                $dwooData->assign('INFO','Label added Succesfully.');
             }
        }


$dwooData->assign('logged',1);
$dwooData->assign('addLabel',1);
$dwoo->output($dwooTpl,$dwooData);

}


}

Template Code

{include(file='header.tpl.html')}


    {if $logged == 1}
    {if $addLabel == 1}
        {if $ERR1}
            {$ERR1}
        {else}
            {if $ERR2}
                {$ERR2}
            {else}
                {$INFO}
            {/if}
         {/if}
    {else}
        Add Label:
        <form method="POST" action="label.php">
        Name: <input type="text" name="labelName"><br>
        <input type="submit" value="add" name="addLabel">
        </form>
        {foreach $labels label}
            {escape($label)}
        {/foreach}
    {/if}
{else}
     You must login to access this page.
{/if}
{include(file='footer.tpl.html')}

---

In this case, turn it into three distinct template files:

• a single $ERRMSG template
• one "You must login.." page
• and a form

The application logic should define which of the three cases gets displayed.