Product Added To Wishlist

It is not clear from product details page whatever product you are about to add to wishlist is already added or not, unless you do it and popup will tell you. How to make a condition

responsive / templates / addons / wishlist / hooks / products / buy_now.pre.tpl

{if !$hide_wishlist_button}
    {include file="addons/wishlist/views/wishlist/components/add_to_wishlist.tpl" but_id="button_wishlist_`$obj_prefix``$product.product_id`" but_name="dispatch[wishlist.add..`$product.product_id`]" but_role="text"}

if this button was named watch, then after clicking watch it would become unwatch ?

Looks like you should check all items in the $smarty.session.wishlist.products array and compare each item with the current product by product_id