Add new condition to Table Rate settings page Reviewing Stock Status

betrs-add-stock-status-condition.php

/**
 * Add ability to find and compare the stock status of items in Table Rate shipping
 * Intended for Use with Per Order setups and Method Conditions
 * https://codecanyon.net/item/table-rate-shipping-for-woocommerce/3796656?ref=bolderelements
 *
 * Code should be added to theme's functions.php file
 */
function betrs_add_stock_status_cond( $conditions ) {
    // add new option to list
    $conditions['stock_status'] = 'Stock Status';
    
    return $conditions;
}
add_filter( 'betrs_shipping_cost_conditionals', 'betrs_add_stock_status_cond', 10, 1 );

function betrs_add_stock_status_cond_secondary( $conditions ) {
    // add new option to list
    $conditions['includes']['conditions'][] = 'stock_status';
    $conditions['excludes']['conditions'][] = 'stock_status';
    
    return $conditions;
}
add_filter( 'betrs_shipping_cost_conditionals_secondary', 'betrs_add_stock_status_cond_secondary', 10, 1 );

function betrs_add_stock_status_cond_tertiary( $type, $item, $row_ID, $option_ID, $cond_key ) {
    // add select box of available stock status options
    $terms = wc_get_product_stock_status_options();
    $op_name_tertiary = ( isset( $option_ID ) ) ? "cond_tertiary[" . $option_ID . "][" . $row_ID . "]" : "method_cond_tertiary";
    $cond_key = abs( $cond_key );
?>
<select name="<?php echo $op_name_tertiary; ?>[<?php echo $cond_key; ?>]" class="cond_tertiary">
        <?php  foreach( $terms as $slug => $status ) :  ?>
    <option value="<?php echo $slug; ?>" <?php selected( $slug, $item['cond_tertiary'], true ); ?>><?php echo $status; ?></option>
        <?php endforeach; ?>
</select>
<?php
}
add_action( 'betrs_shipping_cost_conditionals_tertiary', 'betrs_add_stock_status_cond_tertiary', 10, 5 );

function betrs_add_stock_status_calc( $data, $items ) {
    $status_ar = array();
    
    // determine longest length
    foreach( $items as $key => $values ) {
        $status_ar[] = $values[ 'data' ]->get_stock_status();
    }

    // remove duplicated
    $status_ar = array_unique( $status_ar );
    $data['stock_status'] = $status_ar;

    return $data;
}
add_filter( 'betrs_calculated_totals-per_order', 'betrs_add_stock_status_calc', 10, 2 );

function betrs_determine_condition_stock_status( $return, $cond, $cart_data ) {
    // exit if the custom condition is not a stock status
    if( sanitize_title( $cond['cond_type'] ) != 'stock_status' ) return $return;

    // calculate longest length and init comparison numbers
    $comparison = (array) $cart_data['stock_status'];
    $cond_tertiary = sanitize_title( $cond['cond_tertiary'] );

    // determine how to compare the sum to the setting
    switch( sanitize_text_field( $cond['cond_secondary'] ) ) {
        case 'includes':
            if( in_array( $cond_tertiary, $comparison ) )
                return true;
            break;
        case 'excludes':
            if( ! in_array( $cond_tertiary, $comparison ) )
                return true;
            break;
    }

    // return false if the condition is not met
    return $return;

}
add_filter( 'betrs_determine_condition_result', 'betrs_determine_condition_stock_status', 10, 3 );