Carbon Calculate hours in an interval from a period

<?php

use Carbon\Carbon;
use Carbon\CarbonPeriod;
use Carbon\CarbonInterval;

class PeriodInterval {
    public function hoursIn() {
        /**
        * Time Periods
        */
        $periods = [
            'day' => [
                '08:00:00',
                '18:00:00'
            ],
            'night' => [
                '18:00:00',
                '08:00:00'
            ],
            'lunch' => [
                '11:00:00',
                '14:00:00'
            ]
        ];

        /**
        * Time Intervals
        */
        $intervals = [
            'parking' => [
                'John Doe' => [
                    Carbon::createFromFormat('Y-m-d H:i:s', '2018-12-10 07:00:00'),
                    Carbon::createFromFormat('Y-m-d H:i:s', '2018-12-10 09:00:00')
                ],
                'Jane Doe' => [
                    Carbon::createFromFormat('Y-m-d H:i:s', '2018-12-10 08:00:00'),
                    Carbon::createFromFormat('Y-m-d H:i:s', '2018-12-10 09:00:00')
                ],
                'John Hope' => [
                    Carbon::createFromFormat('Y-m-d H:i:s', '2018-12-10 11:00:00'),
                    Carbon::createFromFormat('Y-m-d H:i:s', '2018-12-10 13:00:00')
                ],
                'Jane Hope' => [
                    Carbon::createFromFormat('Y-m-d H:i:s', '2018-12-10 18:00:00'),
                    Carbon::createFromFormat('Y-m-d H:i:s', '2018-12-10 19:00:00')
                ]
            ]
        ];

        /**
        * Hours for Interval in Period
        */
        function hoursForIntervalInPeriod(array $period, array $interval) {
            $Period = new CarbonPeriod(array_shift($interval)->toDateTimeString(), '1 hour', array_pop($interval)->toDateTimeString());

            return $Period->filter(function($date) use ($period) {
                $period_starts = Carbon::createFromFormat('Y-m-d H:i:s', $date->format('Y-m-d') . ' ' . array_shift($period));
                $period_ends = Carbon::createFromFormat('Y-m-d H:i:s', $date->format('Y-m-d') . ' ' . array_pop($period));

                // Normal Period
                if ($period_starts < $period_ends) {
                    return ($date >= $period_starts && $date < $period_ends);
                }

                // Inverted Period (Overnight)
                if ($period_starts > $period_ends) {
                    return ($date >= $period_starts || $date < $period_ends);
                }

                return false;
            })->count();
        }

        /**
        * Map Everything
        */
        $hours = array_map(function($interval, $interval_key) use ($periods) {
            return array_map(function ($period, $period_key) use ($interval, $interval_key) {
                return [ $interval_key . ucfirst($period_key) => array_map(function($interval_item, $interval_item_key) use ($period) {
                    /**
                    * Calculate Total Hours
                    */
                    $total_hours = hoursForIntervalInPeriod($period, $interval_item);

                    return [ $interval_item_key => $total_hours ];
                }, $interval, array_keys($interval)) ];
            }, $periods, array_keys($periods));
        }, $intervals, array_keys($intervals));

        return $hours;
    }
}