<?php

namespace App\Utilities;

use Carbon\Carbon;
use Carbon\CarbonPeriod;

class WorkingDaysCalculator
{
    public static function calculate(string $month, array $holidays = []): int
    {
        $start = Carbon::createFromFormat('Y-m', $month)->startOfMonth();
        $end = $start->copy()->endOfMonth();

        return self::getWorkingDaysInRange($start->toDateString(), $end->toDateString(), $holidays);
    }

    public static function getWorkingDaysInRange(string $start, string $end, array $holidays = []): int
    {
        $period = CarbonPeriod::create(Carbon::create($start), Carbon::create($end));
        $holidayLookup = array_flip($holidays);
        $workingDays = 0;

        foreach ($period as $day) {
            $date = $day->toDateString();

            if (self::isWorkingDay($date, $holidayLookup)) {
                $workingDays++;
            }
        }

        return $workingDays;
    }

    public static function isWorkingDay(string $date, array $holidays = []): bool
    {
        $carbonDate = Carbon::create($date);

        if ($carbonDate->isWeekend()) {
            return false;
        }

        if (isset($holidays[$carbonDate->toDateString()])) {
            return false;
        }

        return true;
    }
}