feat: split nights off an accommodation booking as separate periods

addresses #869f6z36v

src/Service/GroupsPriceCalculator.php

@@ -86,6 +86,8 @@ class GroupsPriceCalculator
             $nights,
             $dateFrom,
             $dateTo,
+            $dateFrom,
+            $nights,
             $prices,
             $boardService?->getPrice(),
             array_map(
@@ -104,7 +106,12 @@ class GroupsPriceCalculator
      * Same calculation but using frozen snapshot data from an AccommodationBooking entity
      * instead of live catalog entities.
      *
-     * @param AccommodationPrice[]                                                              $prices                     all prices overlapping the booking window
+     * $dateFrom/$dateTo/$nights are the nights being priced, which is the main period of a booking
+     * with split-off periods. $stayDateFrom and $stayNights describe the whole stay, which the
+     * includedPax floor and the short-term surcharge are judged on, so that splitting nights off
+     * never changes either.
+     *
+     * @param AccommodationPrice[]                                                              $prices                     all prices overlapping the whole stay
      * @param list<array{label: string, price: int, type: string, originalServiceId: int|null}> $additionalServiceSnapshots
      *
      * @return array{
@@ -131,6 +138,8 @@ class GroupsPriceCalculator
         int $nights,
         \DateTimeImmutable $dateFrom,
         \DateTimeImmutable $dateTo,
+        \DateTimeImmutable $stayDateFrom,
+        int $stayNights,
         array $prices,
         ?int $boardServicePricePerPersonNight,
         array $additionalServiceSnapshots,
@@ -151,6 +160,8 @@ class GroupsPriceCalculator
             $nights,
             $dateFrom,
             $dateTo,
+            $stayDateFrom,
+            $stayNights,
             $prices,
             $boardServicePricePerPersonNight,
             $items,
@@ -186,15 +197,19 @@ class GroupsPriceCalculator
         int $nights,
         \DateTimeImmutable $dateFrom,
         \DateTimeImmutable $dateTo,
+        \DateTimeImmutable $stayDateFrom,
+        int $stayNights,
         array $prices,
         ?int $boardServicePricePerPersonNight,
         array $additionalItems,
         string $currency,
     ): array {
-        // Derive effectivePax: children 0–3 don't count, but never drop below includedPax
+        // Derive effectivePax: children 0–3 don't count, but never drop below includedPax.
+        // The floor comes from the stay's first night, not the priced range's, so that splitting
+        // nights off the start cannot swap in another price row's floor.
         $firstCandidates = array_values(array_filter(
             $prices,
-            fn (AccommodationPrice $p) => $p->getDateFrom() <= $dateFrom && $p->getDateTo() >= $dateFrom,
+            fn (AccommodationPrice $p) => $p->getDateFrom() <= $stayDateFrom && $p->getDateTo() >= $stayDateFrom,
         ));
         $firstWinner = $this->priceTimelineBuilder->resolveWinner($firstCandidates);
         $includedPaxFloor = $firstWinner?->getIncludedPax() ?? 1;
@@ -239,10 +254,10 @@ class GroupsPriceCalculator
             }
         }
 
-        // Rule 3: short-term surcharge
+        // Rule 3: short-term surcharge, judged on the whole stay but charged on the priced nights
         $shortTermSurcharge = 0;
-        if (isset(self::SHORT_TERM_FACTORS[$nights])) {
-            $shortTermSurcharge = (int) round(($basePrice + $additionalPersonsPrice) * self::SHORT_TERM_FACTORS[$nights] / 100);
+        if (isset(self::SHORT_TERM_FACTORS[$stayNights])) {
+            $shortTermSurcharge = (int) round(($basePrice + $additionalPersonsPrice) * self::SHORT_TERM_FACTORS[$stayNights] / 100);
         }
 
         // Board is only billable — and only triggers the catering surcharge — when it costs