// SAVE the product meta to CART item (does not yet display it though)
add_filter( 'woocommerce_add_cart_item_data', 'fs_save_my_custom_product_field', 10, 2 );
function fs_save_my_custom_product_field( $cart_item_data, $product_id ) {
    $port = get_field( 'port', $product_id, true );
    $fs_duration_monday     = get_field( 'custom_duration_monday', $product_id, true );
    $fs_duration_tuesday    = get_field( 'custom_duration_tuesday', $product_id, true );
    $fs_duration_wednesday  = get_field( 'custom_duration_wednesday', $product_id, true );
    $fs_duration_thursday   = get_field( 'custom_duration_thursday', $product_id, true );
    $fs_duration_friday     = get_field( 'custom_duration_friday', $product_id, true );
    $fs_duration_saturday   = get_field( 'custom_duration_saturday', $product_id, true );
    $fs_duration_sunday     = get_field( 'custom_duration_sunday', $product_id, true );

    if( !empty( $port ) ) {
        $cart_item_data['port'] = $port;

        // below statement make sure every add to cart action as unique line item
        $cart_item_data['unique_key'] = md5( microtime().rand() );
    }
    if( !empty( $fs_duration_monday ) ) {
        $cart_item_data['custom_duration_monday'] = $fs_duration_monday;

        // below statement make sure every add to cart action as unique line item
        $cart_item_data['unique_key'] = md5( microtime().rand() );
    }
    if( !empty( $fs_duration_tuesday ) ) {
        $cart_item_data['custom_duration_tuesday'] = $fs_duration_tuesday;

        // below statement make sure every add to cart action as unique line item
        $cart_item_data['unique_key'] = md5( microtime().rand() );
    }
    if( !empty( $fs_duration_wednesday ) ) {
        $cart_item_data['custom_duration_wednesday'] = $fs_duration_wednesday;

        // below statement make sure every add to cart action as unique line item
        $cart_item_data['unique_key'] = md5( microtime().rand() );
    }
    if( !empty( $fs_duration_thursday ) ) {
        $cart_item_data['custom_duration_thursday'] = $fs_duration_thursday;

        // below statement make sure every add to cart action as unique line item
        $cart_item_data['unique_key'] = md5( microtime().rand() );
    }
    if( !empty( $fs_duration_friday ) ) {
        $cart_item_data['custom_duration_friday'] = $fs_duration_friday;

        // below statement make sure every add to cart action as unique line item
        $cart_item_data['unique_key'] = md5( microtime().rand() );
    }
    if( !empty( $fs_duration_saturday ) ) {
        $cart_item_data['custom_duration_saturday'] = $fs_duration_saturday;

        // below statement make sure every add to cart action as unique line item
        $cart_item_data['unique_key'] = md5( microtime().rand() );
    }
    if( !empty( $fs_duration_sunday ) ) {
        $cart_item_data['custom_duration_sunday'] = $fs_duration_sunday;

        // below statement make sure every add to cart action as unique line item
        $cart_item_data['unique_key'] = md5( microtime().rand() );
    }
    return $cart_item_data;
}

add_filter( 'woocommerce_get_item_data', 'fs_woocommerce_get_item_data', 11, 2 );
function fs_woocommerce_get_item_data( $item_data, $cart_item ) {
    $product_id = isset( $cart_item[ 'product_id' ] ) ? $cart_item[ 'product_id' ] : 0;
    if ( YITH_WCBK_Product_Post_Type_Admin::is_booking( $product_id ) ) {
        /**  @var WC_Product_Booking $product */
        $product = wc_get_product( $product_id );

        $fs_duration_monday     = $cart_item['custom_duration_monday'];
        $fs_duration_tuesday    = $cart_item['custom_duration_tuesday'];
        $fs_duration_wednesday  = $cart_item['custom_duration_wednesday'];
        $fs_duration_thursday   = $cart_item['custom_duration_thursday'];
        $fs_duration_friday     = $cart_item['custom_duration_friday'];
        $fs_duration_saturday   = $cart_item['custom_duration_saturday'];
        $fs_duration_sunday     = $cart_item['custom_duration_sunday'];

        $booking_data           = $cart_item[ 'yith_booking_data' ];

        $from                   = $booking_data[ 'from' ];
        $to                     = $booking_data[ 'to' ];
        $duration               = $booking_data[ 'duration' ];
        $has_time               = in_array( $product->get_duration_unit(), array( 'hour', 'minute' ) );
        $date_format            = wc_date_format();
        $date_format            .= $has_time ? ' ' . wc_time_format() : '';

        // check current day of the Booking Date and see if it matches a particular day of week
        $fs_date_day = date_i18n( 'l', $from );
        // if it does, then force change the Duration display to match the length that was set in the settings
        if( $fs_date_day === 'Monday' && $fs_duration_monday) {
            $duration = $fs_duration_monday;
            $duration_display = $duration . ' hours';
        }
        elseif( $fs_date_day === 'Tuesday' && $fs_duration_tuesday) {
            $duration = $fs_duration_tuesday;
            $duration_display = $duration . ' hours';
        }
        elseif( $fs_date_day === 'Wednesday' && $fs_duration_wednesday) {
            $duration = $fs_duration_wednesday;
            $duration_display = $duration . ' hours';
        }
        elseif( $fs_date_day === 'Thursday' && $fs_duration_thursday) {
            $duration = $fs_duration_thursday;
            $duration_display = $duration . ' hours';
        }
        elseif( $fs_date_day === 'Friday' && $fs_duration_friday ) {
            $duration = $fs_duration_friday;
            $duration_display = $duration . ' hours';
        }
        elseif( $fs_date_day === 'Saturday' && $fs_duration_saturday) {
            $duration = $fs_duration_saturday;
            $duration_display = $duration . ' hours';
        }
        elseif( $fs_date_day === 'Sunday' && $fs_duration_sunday) {
            $duration = $fs_duration_sunday;
            $duration_display = $duration . ' hours';
        }
        // otherwise fallback to the default setting from YITH
        else {
            $duration_display = yith_wcbk_format_duration( $duration, $product->get_duration_unit() );
        }

        // get the original from date again
        $fs_from = $booking_data[ 'from' ];
        $fs_duration_minutes = $duration * 60;
        // get the custom end date by adding new duration in minutes
        $fs_until_new = strtotime('+'. $fs_duration_minutes .' minutes', $fs_from);

        $booking_item_data = array(
            'yith_booking_from'     => array(
                //'key'     => yith_wcbk_get_booking_meta_label( 'from' ),
                'key'     => 'Cruising on',
                'value'   => $from,
                'display' => date_i18n( 'l, F, j Y', $from ) .' from '. date_i18n( wc_time_format(), $from ) .' to '. date_i18n( wc_time_format(), $fs_until_new )
            ),
            'yith_booking_to'       => array(
                'key'     => yith_wcbk_get_booking_meta_label( 'to' ),
                'value'   => $to,
                'display' => date_i18n( $date_format, $to )
            ),
            'yith_booking_duration' => array(
                'key'     => yith_wcbk_get_booking_meta_label( 'duration' ),
                'value'   => $duration,
                'display' => $duration_display
            )
        );

        $item_data = array_merge( $item_data, $booking_item_data );
    }

    return $item_data;
}

/**
 * get booking details from booking data
 *
 * @param array $booking_data
 * @param int   $product_id
 *
 * @return array
 *
 * @since 2.0.6
 */
public function get_booking_order_item_details( $booking_data, $product_id = 0 ) {
    $details = array();
    foreach ( $booking_data as $booking_data_key => $booking_data_value ) {
        $this_title = yith_wcbk_get_booking_meta_label( $booking_data_key );

        switch ( $booking_data_key ) {
            case 'person_types':
                if ( is_array( $booking_data_value ) ) {
                    foreach ( $booking_data_value as $person_type ) {
                        if ( !empty( $person_type[ 'number' ] ) ) {
                            $details[] = array(
                                'key'   => $person_type[ 'title' ],
                                'value' => $person_type[ 'number' ],
                            );
                        }

                    }
                }
                break;
            case 'booking_services':
                if ( is_array( $booking_data_value ) ) {
                    $booking_services        = array();
                    $hidden_booking_services = array();
                    foreach ( $booking_data_value as $service ) {
                        if ( !$service[ 'hidden' ] ) {
                            $booking_services[] = $service[ 'title' ];
                        } else {
                            $hidden_booking_services[] = $service[ 'title' ];
                        }
                    }
                    if ( !!$booking_services ) {
                        $details[] = array(
                            'key'   => yith_wcbk_get_label( 'booking-services' ),
                            'value' => yith_wcbk_booking_services_html( $booking_services ),
                        );
                    }
                    if ( !!$hidden_booking_services ) {
                        $details[] = array(
                            'key'   => '_hidden_booking_services',
                            'value' => yith_wcbk_booking_services_html( $hidden_booking_services ),
                        );
                    }
                }
                break;

            case 'from':
            case 'to':
                /** @var WC_Product_Booking $product */
                $product     = wc_get_product( $product_id );
                $date_format = wc_date_format();
                if ( $product && $product->is_type( 'booking' ) && $product->has_time() ) {
                    $date_format .= ' ' . wc_time_format();
                }
                $this_value = date_i18n( $date_format, $booking_data_value );
                $details[]  = array(
                    'key'   => $this_title,
                    'value' => $this_value,
                );
                break;
            case 'duration':
                $this_value = $booking_data_value;
                $product    = wc_get_product( $product_id );
                if ( $product && $product instanceof WC_Product_Booking ) {
                    $duration_unit       = $product->get_duration_unit();
                    $duration_unit_label = yith_wcbk_get_duration_unit_label( $duration_unit, absint( $booking_data_value ) );
                    $this_value          .= ' ' . $duration_unit_label;
                }
                $details[] = array(
                    'key'   => $this_title,
                    'value' => $this_value,
                );
                break;
            default:
                $details[] = array(
                    'key'   => $this_title,
                    'value' => $booking_data_value,
                );
                break;
        }
    }

    return apply_filters( 'yith_wcbk_order_get_booking_order_item_details', $details, $booking_data, $product_id );
}