EDD Already Purchased Item(s)

file.php

<?php // DO NOT COPY THIS LINE

/**
 * Prevents logged-in customers from purchasing an item twice
 */
function pw_edd_prevent_duplicate_purchase( $valid_data, $posted ) {

	$cart_contents = edd_get_cart_contents();
	foreach( $cart_contents as $item ) {
		if( edd_has_user_purchased( get_current_user_id(), $item['id'] ) ) {
			edd_set_error( 'duplicate_item', 'You have one or more items in the cart that have already been purchased.' );
		}
	}
}
add_action( 'edd_checkout_error_checks', 'pw_edd_prevent_duplicate_purchase', 10, 2 );


/**
 * Add notice next to each item in cart that has been purchased
 */
function sd_already_purchased_notice( $item ) {

	if ( edd_has_user_purchased( get_current_user_id(), $item['id'] ) ) {
		echo ' <small>(already purchased)</small>';
	}
}
add_action( 'edd_checkout_cart_item_title_after', 'sd_already_purchased_notice' );