feat: indicate family insurance eligibility

src/Service/FamilyInsuranceAvailabilityChecker.php

@@ -0,0 +1,82 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Service;
+
+use App\BusProNet\Model\Insurance;
+use App\Form\Model\BookingDto;
+
+/**
+ * Single source of truth for "the applicant could still upgrade to a family insurance".
+ *
+ * Participants are entered one card at a time, applicant first, so at the moment the
+ * applicant has to pick an insurance the family constellation is not yet known and no
+ * family insurance can be offered. Only the applicant may hold a family insurance, so
+ * without a standing hint the opportunity is silently lost once the dependents' dates
+ * of birth make the booking eligible.
+ *
+ * This is deliberately a derived predicate rather than a one-time event: it stays true
+ * for as long as the applicant can still act on it and disappears by itself once they
+ * switch to a family insurance, deliberately pick something else while eligible, or the
+ * constellation stops qualifying.
+ */
+class FamilyInsuranceAvailabilityChecker
+{
+    public function __construct(
+        private readonly InsuranceManager $insuranceService,
+        private readonly BookingPriceCalculator $priceCalculatorService,
+    ) {
+    }
+
+    /**
+     * Whether the applicant should be pointed at a family insurance they cannot have
+     * chosen earlier.
+     *
+     * Requires `applicantInsuranceChosenWhileFamilyIneligible` - i.e. the standing choice
+     * was actually made before family insurance was possible - so an applicant who was
+     * offered a family insurance and picked something else is not nagged about it.
+     */
+    public function isFamilyInsuranceUpgradeAvailable(BookingDto $bookingDto): bool
+    {
+        if (false === $bookingDto->applicantInsuranceChosenWhileFamilyIneligible) {
+            return false;
+        }
+
+        $applicant = $bookingDto->getParticipant(0);
+
+        if (null === $applicant || null === $applicant->insurance || true === $applicant->insurance->familyInsurance) {
+            return false;
+        }
+
+        return $this->hasEligibleFamilyInsurance($bookingDto);
+    }
+
+    /**
+     * Checks whether a family insurance is actually eligible right now - not just whether
+     * the participant composition qualifies as a family booking, but whether a selectable
+     * family insurance product actually matches the current total booking price.
+     */
+    public function hasEligibleFamilyInsurance(BookingDto $bookingDto): bool
+    {
+        if (false === $bookingDto->isFamilyBooking()) {
+            return false;
+        }
+
+        $applicant = $bookingDto->getParticipant(0);
+        if (null === $applicant) {
+            return false;
+        }
+
+        $selectableInsurances = $this->insuranceService->getSelectableInsurances($bookingDto->travel);
+        $familyInsurances = array_values(array_filter($selectableInsurances, static fn (Insurance $i) => true === $i->familyInsurance));
+
+        if ([] === $familyInsurances) {
+            return false;
+        }
+
+        $totalPrice = $this->priceCalculatorService->calculateTotalBookingPriceExcludingInsurance($bookingDto);
+
+        return [] !== $this->insuranceService->getEligibleInsurances($familyInsurances, $applicant, $bookingDto, $totalPrice);
+    }
+}