Magento: Redirect to login page while user not login on landing

Redirect User To Login If User Is Not Logged In

<?php
    $redirect_url = Mage::getUrl('customer/account/login/');
    $current_url = Mage::helper('core/url')->getCurrentUrl();
    if((!$this->helper('customer')->isLoggedIn()) && ($current_url != $redirect_url)){
        Mage::app()->getFrontController()->getResponse()->setRedirect($redirect_url);
    }
?>

Or a login Link To see Product details for non-logged in user:

<?php
    if(!Mage::helper('customer')->isLoggedIn()) {
        Mage::getSingleton('customer/session')->setBeforeAuthUrl(Mage::helper('core/url')->getCurrentUrl()); ?>
        <p>Please <a href="<?php echo Mage::getUrl('customer/account/login'); ?>" >Login </a>to view the product Details.</p><?php
    }
    else{
        //Your product details here:
    }
?>