JetBooking. Allow to book multiple units at single purchase

jet-booking-muliple-units.php

<?php
/**
 * Allow to book multiple units/appartments/tickets at same date/dates with single purchase
 * You need to add '_capacity' field into the form. This field should be responsible for number of booked items
 */
add_filter( 'jet-booking/form-action/pre-process', function( $result, $booking, $action ) {

	$capacity = absint( $action->getRequest( '_capacity' ) );

	if ( ! $capacity && 1 === $capacity ) {
		return $result;
	}

	$booking_ids = [];

	$all_units = \JET_ABAF\Plugin::instance()->db->get_apartment_units( $booking['apartment_id'] );

	if ( empty( $all_units ) ) {
		return $result;
	}

	$booked_units       = \JET_ABAF\Plugin::instance()->db->get_booked_units( $booking );
	$all_units_count    = count( $all_units );
	$booked_units_count = count( $booked_units );

	if ( ( $available_units = $all_units_count - $booked_units_count ) < $capacity ) {
		throw new JET_ABAF\Vendor\Actions_Core\Base_Handler_Exception( 
			'Not enough available units. Only ' . $available_units . ' are available',
			'error'
		);
	}

	for ( $i = 1; $i <= $capacity; $i++ ) { 
		
		$booking_id = \JET_ABAF\Plugin::instance()->db->insert_booking( $booking );

		if ( $booking_id ) {
			$booking_ids = $booking_id;
		} else {
			throw new \JET_ABAF\Vendor\Actions_Core\Base_Handler_Exception( 
				esc_html__( 'Booking dates already taken', 'jet-booking' ),
				'error'
			);
		}

	}

	$action->setRequest( 'booking_id', implode( ',', $booking_ids ) );
	$action->setRequest( 'booking_ids', $booking_ids );

	return $booking;

}, 10, 3 );