Hide free shipping when subtotal is greater than 0 in WooCommerce - php

Question

I'm using Free Product Sample for the WooCommerce plugin and trying to set conditional free shipping only for a Sample product, sample product cost is 0 and therefore I'm trying to hide free shipping unless the order subtotal amount is 0.
To put it in a nutshell:
I want to offer free shipping only for sample products and, the free shipping method should only visible for a product having subtotal = 0
Screenshot for further clarification:
My attempted code:
function ts_hide_shipping_for_order_total( $rates ) {
$rate = array();
$order_total = WC()->cart->get_subtotal();
if( $order_total > 0 ) {
foreach ( $rates as $rate_id => $rate ) {
if ( 'free_shipping:20' === $rate->get_method_id() ) {
$rate[ $rate_id ] = $rate;
}
}
}
return ! empty( $free ) ? $free : $rates;
}
add_filter( 'woocommerce_package_rates', 'ts_hide_shipping_for_order_total', 100 );
OR
add_filter( 'woocommerce_package_rates', 'hide_shipping_except_local_when_free_is_available', 100 );
function hide_shipping_except_local_when_free_is_available($rates) {
$free = $local = array();
foreach ( $rates as $rate_id => $rate ) {
if ( 'free_shipping:20' === $rate->method_id ) {
$free[ $rate_id ] = $rate;
}
}
return ! empty( $free ) ? array_merge( $free, $local ) : $rates;
}
But both codes do not give me the desired result. Can anyone point me in the right direction?

Answer 1

To hide/unset the "free shipping", as long as the subtotal is greater than 0, you can use the following.
So you get:
function filter_woocommerce_package_rates( $rates, $package ) {
// Get subtotal
$subtotal = $package['cart_subtotal'];
// Hide free shipping if subtotal > 0
if ( $subtotal > 0 ) {
// Loop trough
foreach ( $rates as $rate_id => $rate ) {
if ( $rate->method_id === 'free_shipping' ) {
unset( $rates[$rate_id] );
}
}
}
return $rates;
}
add_filter( 'woocommerce_package_rates', 'filter_woocommerce_package_rates', 10, 2 );
Additional question: Hide the other methods when subtotal <= 0
function filter_woocommerce_package_rates( $rates, $package ) {
// Get subtotal
$subtotal = $package['cart_subtotal'];
// Loop trough
foreach ( $rates as $rate_id => $rate ) {
if ( $rate->method_id === 'free_shipping' ) {
// Hide free shipping if subtotal > 0
if ( $subtotal > 0 ) {
unset( $rates[$rate_id] );
}
} else {
// Hide other methods when subtotal <= 0
if ( $subtotal <= 0 ) {
unset( $rates[$rate_id] );
}
}
}
return $rates;
}
add_filter( 'woocommerce_package_rates', 'filter_woocommerce_package_rates', 10, 2 );