Помогите, пожалуйста, как пояснить коды, срочно!!!

action_add();
}else if(isset($_POST['save']))
$carsController->action_save();
else if(isset($_POST['edit']))
$carsController->action_edit();
else if(isset($_POST['delete']))
$carsController->action_delete();
else if(isset($_POST['viewcontracts']))
{
if(isset($_POST['checkboxcar']) && count($_POST['checkboxcar']) > 0)
{
$contractsController = new contractsController();
$contractsController->action_filter_by_cars();
}
else
$carsController->action_index();
}
else
$carsController->action_index();
}
else
{
header('Location: login.php');
}
?>

action_add();
}else if(isset($_POST['save']))
$carsController->action_save();
else if(isset($_POST['edit']))
$carsController->action_edit();
else if(isset($_POST['delete']))
$carsController->action_delete();
else if(isset($_POST['viewcontracts']))
{ if(isset($_POST['checkboxcar']) && count($_POST['checkboxcar']) > 0)
{ $contractsController = new contractsController();
$contractsController->action_filter_by_cars();}
else
$carsController->action_index();}
else
$carsController->action_index();}
else
{ header('Location: login.php');}
?>