display state field when not available in checkout page

display state field when not available in checkout page

class Custom_State_Field_Handler {

    public function __construct() {
        add_filter( 'wfacp_form_section', [ $this, 'inject_state_into_form_section' ], 10 );
        add_filter( 'wfacp_checkout_fields', [ $this, 'inject_state_into_checkout_fields' ], 10 );
    }

    /**
     * Injects state field into form section after country field if missing.
     */
    public function inject_state_into_form_section( $section ) {
        if ( ! empty( $section['fields'] ) && is_array( $section['fields'] ) ) {

            $country_field_ids = [ 'billing_country', 'shipping_country' ];
            $state_field_ids   = [ 'billing_state', 'shipping_state' ];

            $existing_field_ids = wp_list_pluck( $section['fields'], 'id' );
            $new_fields = [];

            foreach ( $section['fields'] as $field ) {
                $new_fields[] = $field;

                if ( isset( $field['id'] ) && in_array( $field['id'], $country_field_ids ) ) {
                    $country_id = $field['id'];
                    $index      = array_search( $country_id, $country_field_ids, true );
                    $state_id   = $state_field_ids[ $index ];

                    if ( ! in_array( $state_id, $existing_field_ids, true ) ) {
                        $state_field = $this->get_state_field_array( $state_id, $country_id, $field['class'], $field['field_type'] );
                        $new_fields[] = $state_field;
                    }
                }
            }

            $section['fields'] = $new_fields;
        }

        return $section;
    }

    /**
     * Injects state field into checkout fields array when wp_doing_ajax().
     */
    public function inject_state_into_checkout_fields( $fields ) {
        if ( wp_doing_ajax() ) {
            $country_field_ids = [ 'billing_country', 'shipping_country' ];
            $state_field_ids   = [ 'billing_state', 'shipping_state' ];

            foreach ( $country_field_ids as $index => $country_id ) {
                $state_id = $state_field_ids[ $index ];

                foreach ( [ 'billing', 'shipping' ] as $group ) {
                    if ( isset( $fields[ $group ] ) ) {
                        if ( isset( $fields[ $group ][ $country_id ] ) && ! isset( $fields[ $group ][ $state_id ] ) ) {
                            $class      = isset( $fields[ $group ][ $country_id ]['class'] ) ? $fields[ $group ][ $country_id ]['class'] : [ 'form-row-wide' ];
                            $field_type = $group;

                            $fields[ $group ][ $state_id ] = $this->get_state_field_array( $state_id, $country_id, $class, $field_type );
                        }
                    }
                }
            }
        }

        return $fields;
    }

    /**
     * Returns a consistent state field array.
     */
    private function get_state_field_array( $state_id, $country_id, $class, $field_type ) {
        return [
            'type'          => 'state',
            'label'         => 'State',
            'required'      => false,
            'class'         => $class,
            'priority'      => 80,
            'country_field' => $country_id,
            'cssready'      => [],
            'field_type'    => $field_type,
            'placeholder'   => '',
            'id'            => $state_id,
            'address_group' => 1,
        ];
    }
}

// Initialize
new Custom_State_Field_Handler();