app/classes/ReleaseInsights/Duration.php

<?php

declare(strict_types=1);

namespace ReleaseInsights;

use DateInterval, DatePeriod, DateTime;

/**
 * Calculate durations in days and working days to indicate working days left in schedules
 */
class Duration
{
   /** @var array<string> $wellness_days */
    private readonly array $wellness_days;

    public function __construct(
        public readonly Datetime $start,
        public readonly Datetime $end
    )
    {
        $this->wellness_days = include DATA . 'wellness_days.php';
    }

    /**
     * Get The number of days between 2 dates
     */
    public function days(): int
    {
        return $this->start->diff($this->end)->days;
    }

    /**
     * Get The number of weeks between 2 dates
     * We round down to 0.5
     */
    public function weeks(): float
    {
        // We are limiting to 1 decimal for the week
        $weeks = number_format($this->days()/7, 1);

        // We want some logic to round down only the decimal to 0.5
        [$main, $minor] = explode('.', (string) $weeks);
        $minor =  $minor >= 5 ? 5 : 0;

        return (float) ($main . '.' . $minor);
    }

    /**
     * Check if a day is a workday
     */
    public function isWorkDay(DateTime $day): bool
    {
        // We don't consider the current day as a working day
        if ($day->format('Y-m-d') === new DateTime()->format('Y-m-d')) {
            return false;
        }

        // We substract week-end days
        if (in_array($day->format('l'), ['Saturday','Sunday'])) {
            return false;
        }

        // We substract wellness days
        if (in_array($day->format('Y-m-d'), $this->wellness_days)) {
            return false;
        }

        return true;
    }

    /**
     * Get The number of working days between 2 dates
     */
    public function workDays(): int
    {
        $count = 0;

        // P1D is short for 'Period: 1 Day'
        $range = new DatePeriod(start: $this->start, end: $this->end, interval: new DateInterval('P1D'));

        foreach($range as $date){

            if ($this->isWorkDay($date)) {
                $count++;
            }
        }

        return $count;
    }

    /**
     * Return all the data in an array for template use
     *
     * @return array<string, float|int>
     */
    public function report(): array
    {
        return [
            'days'     => $this->days(),
            'workdays' => $this->workDays(),
            'weeks'    => $this->weeks(),
        ];
    }
}