IF $class = ($value->status == "done") HOW?

Guys, I would like to use this to show three different colors on my gantt chart:

Code:

$class = ($value->status == "done") ? "#336699" : "";

Currently I have one color, that shows done tasks
Is this possible to use something like:

Code:

if $class = ($value->status == "open") ? "#536699" : "";
if $class = ($value->status == "in_progress") ? "#796699" : "";
if $class = ($value->status == "done") ? "#336699" : "";

But of course above code doesn't work. Can You please help me to create some "if" listing for that?