feat: add multiple working day determiner

app/Services/WorkingDays/Utils/MultipleWorkingDayDeterminer.php

@@ -0,0 +1,42 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Services\WorkingDays\Utils;
+
+use App\Services\WorkingDays\WorkingDayDeterminerInterface;
+
+/**
+ * Determines if a given date is a working day -- on multiple working day determiners.
+ */
+class MultipleWorkingDayDeterminer implements WorkingDayDeterminerInterface
+{
+    /**
+     * @param array<int, WorkingDayDeterminerInterface> $workingDayDeterminers
+     */
+    public function __construct(
+        protected readonly array $workingDayDeterminers,
+    ) {
+    }
+
+    public function isWorkingDay(\DateTimeImmutable $date): bool
+    {
+        foreach ($this->workingDayDeterminers as $workingDayDeterminer) {
+            if (!$workingDayDeterminer->isWorkingDay($date)) {
+                return false;
+            }
+        }
+        return true; // All working day determiners returned true, so the date is a working day.
+    }
+
+    public function getWorkingDaysCount(\DateTimeImmutable $startDate, int $workingDays): int
+    {
+        $workingDaysCount = $workingDays;
+
+        foreach ($this->workingDayDeterminers as $workingDayDeterminer) {
+            $workingDaysCount = min($workingDaysCount, $workingDayDeterminer->getWorkingDaysCount($startDate, $workingDays));
+        }
+
+        return $workingDaysCount;
+    }
+}