fix: incorrect rules around family insurances

addresses #869dr80qj

src/Service/BookingPriceCalculator.php

@@ -4,6 +4,7 @@ declare(strict_types=1);
 
 namespace App\Service;
 
+use App\BusProNet\Model\Insurance;
 use App\Form\Model\BookingDto;
 
 /**
@@ -76,6 +77,22 @@ class BookingPriceCalculator
         return $this->participantPricingCalculator->calculateAllParticipantIndividualPrices($bookingDto);
     }
 
+    /**
+     * Calculates total booking price across all participants, excluding insurance.
+     *
+     * Used for family insurance price-tier determination, where the tier is based on
+     * the combined trip cost rather than any single participant's price.
+     */
+    public function calculateTotalBookingPriceExcludingInsurance(BookingDto $bookingDto): float
+    {
+        $total = 0.0;
+        foreach ($bookingDto->getParticipants() as $index => $participant) {
+            $total += $this->calculateIndividualParticipantPriceExcludingInsurance($bookingDto, $index);
+        }
+
+        return $total;
+    }
+
     /**
      * Calculates the total price for an individual participant excluding insurance.
      *
@@ -95,4 +112,22 @@ class BookingPriceCalculator
             $participantIndex
         );
     }
+
+    /**
+     * Resolves the travel price to use for insurance eligibility checks.
+     *
+     * Family insurances are always evaluated against the total booking price (all
+     * participants combined); everything else uses the individual participant's price.
+     * Non-applicant participants can never hold a family insurance (InsuranceManager
+     * restricts family insurances to the applicant), so this does not need to know
+     * whether $participantIndex is the applicant.
+     */
+    public function resolveInsuranceTravelPrice(BookingDto $bookingDto, int $participantIndex, Insurance $insurance): float
+    {
+        if (true === $insurance->familyInsurance) {
+            return $this->calculateTotalBookingPriceExcludingInsurance($bookingDto);
+        }
+
+        return $this->calculateIndividualParticipantPriceExcludingInsurance($bookingDto, $participantIndex);
+    }
 }