feat: replace custom discount with absolute value in favor of percentage

docs/api-consumer-guide.md

@@ -276,7 +276,7 @@ Single booking by UUID. `404 {"message":"Not found"}` if unknown.
   "accommodationDiscount": null,
   "boardServiceDiscount": null,
   "additionalServicesDiscount": null,
-  "totalDiscount": null,
+  "totalDiscountAmount": null,
   "totalDiscountLabel": null,
   "totalPrice": 123456,
   "pricingCurrency": "EUR",
@@ -285,19 +285,19 @@ Single booking by UUID. `404 {"message":"Not found"}` if unknown.
 }
 ```
 
-`totalPrice` is in integer **minor units** (cents) — unlike the contingent endpoints. The `*Discount` fields are whole **percentages** (1–100) or `null`, not amounts. `dateFrom`/`dateTo` are `Y-m-d`; `acceptedAt` is a full ISO-8601 datetime and is `null` until accepted. `priceBreakdown` is a computed nested structure.
+`totalPrice` and `totalDiscountAmount` are integer **minor units** (cents) — unlike the contingent endpoints. The three `*Discount` fields are whole **percentages** (1–100) or `null`, not amounts. `dateFrom`/`dateTo` are `Y-m-d`; `acceptedAt` is a full ISO-8601 datetime and is `null` until accepted. `priceBreakdown` is a computed nested structure.
 
 The first three discounts each apply to one section of the breakdown: `accommodationDiscount` to `basePrice + additionalPersonsPrice`, `boardServiceDiscount` to `boardPrice`, `additionalServicesDiscount` to `servicesPrice`. Surcharges and running costs sit in `total` but in no section, so they are never discounted.
 
-`totalDiscount` is a freely named discount on the whole price, labelled by `totalDiscountLabel`. **It compounds**: the three section discounts reduce `total` first, and `totalDiscount` then applies to that already-reduced subtotal. Recomputing it against the gross `total` yields a different figure. Each amount is rounded to the nearest cent at the step it is applied.
+`totalDiscountAmount` is a freely named discount on the whole price, labelled by `totalDiscountLabel`. It is a fixed sum, not a percentage, and is subtracted **after** the three section discounts have reduced `total`. It is capped at what is left of that subtotal, so `discountedTotal` is never negative and the amount shown in the breakdown may be smaller than `totalDiscountAmount` itself. The section discounts are each rounded to the nearest cent as they are applied.
 
 `priceBreakdown` carries the resulting rows, all in minor units:
 
 | field | meaning |
 | --- | --- |
 | `discounts` | list of `{label, percent, amount}` for the section discounts; entries rounding to `0` are omitted, and `label` already includes its `Rabatt ` prefix |
-| `discountSubtotal` | `total` minus the section discounts — present only when `totalDiscount` applies *and* at least one section discount did, otherwise `null` |
+| `discountSubtotal` | `total` minus the section discounts — present only when `totalDiscountAmount` applies *and* at least one section discount did, otherwise `null` |
-| `totalDiscountDetails` | `{label, percent, amount}` for the total discount, or `null` |
+| `totalDiscountDetails` | `{label, amount}` for the total discount, or `null`; `amount` is the capped figure actually subtracted |
 | `discountedTotal` | the final price, equal to the booking's `totalPrice` |
 
 #### `POST /api/accommodation-bookings/{uuid}/accept` — scope `api`

migrations/Version20260908161500.php

@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+namespace DoctrineMigrations;
+
+use Doctrine\DBAL\Schema\Schema;
+use Doctrine\Migrations\AbstractMigration;
+
+/**
+ * The percentage column is dropped rather than converted: it shipped with Version20260908145156
+ * but no booking was ever given a value, so there is nothing to carry over.
+ */
+final class Version20260908161500 extends AbstractMigration
+{
+    public function getDescription(): string
+    {
+        return 'Store the accommodation booking total discount as an absolute amount in minor units instead of a percentage';
+    }
+
+    public function up(Schema $schema): void
+    {
+        $this->addSql('ALTER TABLE accommodation_booking DROP total_discount, ADD total_discount_amount INT DEFAULT NULL');
+    }
+
+    public function down(Schema $schema): void
+    {
+        $this->addSql('ALTER TABLE accommodation_booking DROP total_discount_amount, ADD total_discount INT DEFAULT NULL');
+    }
+}

src/Controller/Admin/AccommodationBooking/EditController.php

@@ -91,6 +91,7 @@ class EditController extends AbstractController
             'current_board_service' => $currentBoardService,
             'current_additional_services' => $currentAdditionalServices,
             'assignable_managers' => $assignableManagers,
+            'currency' => $booking->getPricingCurrency() ?? $accommodation?->getCurrency() ?? 'EUR',
         ]);
         $form->handleRequest($request);
 

src/Entity/Groups/AccommodationBooking.php

@@ -156,13 +156,14 @@ class AccommodationBooking implements BlameableEntityInterface, TimestampableEnt
     #[Assert\Range(min: 1, max: 100)]
     private ?int $additionalServicesDiscount = null;
 
+    /** Absolute discount on the total, in minor units. Applied after the three section discounts. */
     #[ORM\Column(nullable: true)]
-    #[Assert\Range(min: 1, max: 100)]
+    #[Assert\Positive]
-    private ?int $totalDiscount = null;
+    private ?int $totalDiscountAmount = null;
 
     #[ORM\Column(length: 255, nullable: true)]
     #[Assert\Expression(
-        'null === this.getTotalDiscount() or (null !== value and "" !== value)',
+        'null === this.getTotalDiscountAmount() or (null !== value and "" !== value)',
         message: 'Bitte eine Bezeichnung für den Rabatt angeben.',
     )]
     private ?string $totalDiscountLabel = null;
@@ -649,14 +650,14 @@ class AccommodationBooking implements BlameableEntityInterface, TimestampableEnt
         return $this;
     }
 
-    public function getTotalDiscount(): ?int
+    public function getTotalDiscountAmount(): ?int
     {
-        return $this->totalDiscount;
+        return $this->totalDiscountAmount;
     }
 
-    public function setTotalDiscount(?int $totalDiscount): self
+    public function setTotalDiscountAmount(?int $totalDiscountAmount): self
     {
-        $this->totalDiscount = $totalDiscount;
+        $this->totalDiscountAmount = $totalDiscountAmount;
 
         return $this;
     }

src/Form/Admin/Groups/AccommodationBookingType.php

@@ -14,11 +14,13 @@ use Symfony\Component\Form\Extension\Core\Type\ChoiceType;
 use Symfony\Component\Form\Extension\Core\Type\DateType;
 use Symfony\Component\Form\Extension\Core\Type\EmailType;
 use Symfony\Component\Form\Extension\Core\Type\IntegerType;
+use Symfony\Component\Form\Extension\Core\Type\MoneyType;
 use Symfony\Component\Form\Extension\Core\Type\TextareaType;
 use Symfony\Component\Form\Extension\Core\Type\TextType;
 use Symfony\Component\Form\FormBuilderInterface;
 use Symfony\Component\Form\FormInterface;
 use Symfony\Component\OptionsResolver\OptionsResolver;
+use Symfony\Component\Validator\Constraints\Positive;
 use Symfony\Component\Validator\Constraints\Range;
 
 /** @extends AbstractType<AccommodationBooking> */
@@ -158,14 +160,17 @@ class AccommodationBookingType extends AbstractType
                     new Range(min: 1, max: 100),
                 ],
             ])
-            // Applies to the total after the three section discounts. The label is not marked
+            // A fixed sum, not a percentage, applied to the total after the three section
-            // required here — a percentage may legitimately be absent — but the entity refuses
+            // discounts. The label is not marked required here — an amount may legitimately be
-            // a percentage without one, so no unnamed discount can reach the customer.
+            // absent — but the entity refuses an amount without one, so no unnamed discount can
-            ->add('totalDiscount', IntegerType::class, [
+            // reach the customer.
-                'label' => 'Rabatt Gesamtpreis (%)',
+            ->add('totalDiscountAmount', MoneyType::class, [
+                'label' => 'Rabatt Gesamtpreis',
+                'currency' => $options['currency'],
+                'divisor' => 100,
                 'required' => false,
                 'constraints' => [
-                    new Range(min: 1, max: 100),
+                    new Positive(),
                 ],
             ])
             ->add('totalDiscountLabel', TextType::class, [
@@ -201,6 +206,7 @@ class AccommodationBookingType extends AbstractType
             'current_board_service' => null,
             'current_additional_services' => [],
             'assignable_managers' => [],
+            'currency' => 'EUR',
         ]);
         $resolver->setAllowedTypes('max_adolescent_age', 'int');
         $resolver->setAllowedTypes('board_services', 'array');
@@ -208,5 +214,6 @@ class AccommodationBookingType extends AbstractType
         $resolver->setAllowedTypes('current_board_service', ['null', BoardService::class]);
         $resolver->setAllowedTypes('current_additional_services', 'array');
         $resolver->setAllowedTypes('assignable_managers', 'array');
+        $resolver->setAllowedTypes('currency', 'string');
     }
 }

src/Model/AccommodationBookingApiResponse.php

@@ -73,9 +73,9 @@ final readonly class AccommodationBookingApiResponse
     #[Groups(['api:single'])]
     public ?int $additionalServicesDiscount;
 
-    /** Applies to the total after the three section discounts above, not to the gross total. */
+    /** An absolute amount in minor units, subtracted after the three section discounts above. */
     #[Groups(['api:single'])]
-    public ?int $totalDiscount;
+    public ?int $totalDiscountAmount;
 
     #[Groups(['api:single'])]
     public ?string $totalDiscountLabel;
@@ -122,7 +122,7 @@ final readonly class AccommodationBookingApiResponse
         $this->accommodationDiscount = $booking->getAccommodationDiscount();
         $this->boardServiceDiscount = $booking->getBoardServiceDiscount();
         $this->additionalServicesDiscount = $booking->getAdditionalServicesDiscount();
-        $this->totalDiscount = $booking->getTotalDiscount();
+        $this->totalDiscountAmount = $booking->getTotalDiscountAmount();
         $this->totalDiscountLabel = $booking->getTotalDiscountLabel();
         $this->totalPrice = $booking->getTotalPrice();
         $this->pricingCurrency = $booking->getPricingCurrency();

src/Service/AccommodationBookingBreakdownCalculator.php

@@ -43,7 +43,8 @@ class AccommodationBookingBreakdownCalculator
     public function withDiscounts(AccommodationBooking $booking, array $breakdown): array
     {
         // The labels carry their own "Rabatt" prefix so that every row renders as plain
-        // {label} {percent} %, including the freely named discount on the total below.
+        // {label} {percent} %, while the freely named discount on the total below is a fixed
+        // amount and renders as its label alone.
         $buckets = [
             ['Rabatt Unterkunft', $booking->getAccommodationDiscount(), (int) ($breakdown['basePrice'] ?? 0) + (int) ($breakdown['additionalPersonsPrice'] ?? 0)],
             ['Rabatt Verpflegung', $booking->getBoardServiceDiscount(), (int) ($breakdown['boardPrice'] ?? 0)],
@@ -70,15 +71,15 @@ class AccommodationBookingBreakdownCalculator
         // computing the new total, where the stored one is still the outdated value.
         $subtotal = (int) ($breakdown['total'] ?? 0) - $discountSum;
 
-        // Compounds on the already-reduced subtotal rather than on the gross total: the discount
+        // A fixed sum rather than a percentage, subtracted after the section discounts. Clamped to
-        // is granted on what the customer would otherwise pay, not on a figure no longer asked.
+        // what is left of the subtotal so that a discount larger than the price cannot produce a
-        $totalDiscountAmount = self::discountAmount($subtotal, $booking->getTotalDiscount());
+        // negative total, the same guard BookingSummaryAssembler applies to vouchers.
+        $totalDiscountAmount = min($booking->getTotalDiscountAmount() ?? 0, max(0, $subtotal));
 
         $breakdown['discounts'] = $discounts;
         $breakdown['totalDiscountDetails'] = 0 !== $totalDiscountAmount
             ? [
                 'label' => (string) $booking->getTotalDiscountLabel(),
-                'percent' => $booking->getTotalDiscount(),
                 'amount' => $totalDiscountAmount,
             ]
             : null;

templates/admin/accommodation_booking/edit.html.twig

@@ -81,7 +81,7 @@
         </div>
         <div class="lg:col-span-2 grid lg:grid-cols-2 gap-y-4 lg:gap-x-8">
             {{ form_row(form.totalDiscountLabel) }}
-            {{ form_row(form.totalDiscount) }}
+            {{ form_row(form.totalDiscountAmount) }}
         </div>
         <div class="lg:col-span-2">
             {{ form_row(form.remarks) }}

templates/admin/accommodation_booking/index.html.twig

@@ -84,8 +84,8 @@
                             {% if booking.additionalServicesDiscount is not null %}
                                 {% set discounts = discounts | merge(['Zusatzleistungen ' ~ booking.additionalServicesDiscount ~ '%']) %}
                             {% endif %}
-                            {% if booking.totalDiscount is not null %}
+                            {% if booking.totalDiscountAmount is not null %}
-                                {% set discounts = discounts | merge([(booking.totalDiscountLabel ?: 'Gesamtpreis') ~ ' ' ~ booking.totalDiscount ~ '%']) %}
+                                {% set discounts = discounts | merge([(booking.totalDiscountLabel ?: 'Gesamtpreis') ~ ' ' ~ ((booking.totalDiscountAmount / 100) | format_currency(booking.pricingCurrency ?: 'EUR'))]) %}
                             {% endif %}
                             <a href="{{ edit_url }}">{{ discounts | length > 0 ? (discounts | join(', ')) : '–' }}</a>
                         </td>

templates/admin/accommodation_booking/show.html.twig

@@ -160,7 +160,7 @@
                     {% endif %}
                     {% if priceBreakdown.totalDiscountDetails is not null %}
                         <tr class="text-green-700">
-                            <td class="pt-1">{{ priceBreakdown.totalDiscountDetails.label }} {{ priceBreakdown.totalDiscountDetails.percent }}&nbsp;%</td>
+                            <td class="pt-1">{{ priceBreakdown.totalDiscountDetails.label }}</td>
                             <td class="pt-1 text-right whitespace-nowrap">– {{ (priceBreakdown.totalDiscountDetails.amount / 100) | format_currency(currency) }}</td>
                         </tr>
                     {% endif %}

templates/email/_price_breakdown.html.twig

@@ -89,7 +89,7 @@
         {% endif %}
         {% if priceBreakdown.totalDiscountDetails is not null %}
             <tr>
-                <td style="{{ cell }}">{{ priceBreakdown.totalDiscountDetails.label }} {{ priceBreakdown.totalDiscountDetails.percent }}&nbsp;%</td>
+                <td style="{{ cell }}">{{ priceBreakdown.totalDiscountDetails.label }}</td>
                 <td style="{{ amount }}">– {{ (priceBreakdown.totalDiscountDetails.amount / 100)|format_currency(currency) }}</td>
             </tr>
         {% endif %}

templates/groups/offer/_summary.html.twig

@@ -164,7 +164,7 @@
                     {% endif %}
                     {% if ctx.priceBreakdown.totalDiscountDetails is not null %}
                         <tr class="text-green-700">
-                            <td class="p-2">{{ ctx.priceBreakdown.totalDiscountDetails.label }} {{ ctx.priceBreakdown.totalDiscountDetails.percent }}&nbsp;%</td>
+                            <td class="p-2">{{ ctx.priceBreakdown.totalDiscountDetails.label }}</td>
                             <td class="p-2 text-right whitespace-nowrap">– {{ (ctx.priceBreakdown.totalDiscountDetails.amount / 100)|format_currency(currency) }}</td>
                         </tr>
                     {% endif %}

tests/Controller/Api/AccommodationBookingControllerTest.php

@@ -56,7 +56,7 @@ class AccommodationBookingControllerTest extends TestCase
         $booking->setAccommodationDiscount(10);
         $booking->setBoardServiceDiscount(20);
         $booking->setAdditionalServicesDiscount(30);
-        $booking->setTotalDiscount(5);
+        $booking->setTotalDiscountAmount(5000);
         $booking->setTotalDiscountLabel('Treuerabatt');
         $booking->setStatus(AccommodationBookingStatus::Confirmed);
         $booking->setOrigin(AccommodationBookingOrigin::Direct);
@@ -129,7 +129,7 @@ class AccommodationBookingControllerTest extends TestCase
             'accommodationDiscount' => 10,
             'boardServiceDiscount' => 20,
             'additionalServicesDiscount' => 30,
-            'totalDiscount' => 5,
+            'totalDiscountAmount' => 5000,
             'totalDiscountLabel' => 'Treuerabatt',
             'totalPrice' => 11111,
             'pricingCurrency' => 'EUR',

tests/Form/Admin/Groups/AccommodationBookingTypeTest.php

@@ -74,13 +74,13 @@ class AccommodationBookingTypeTest extends TestCase
     }
 
     /**
-     * The label is printed verbatim on the customer's PDF, so a percentage without one is
+     * The label is printed verbatim on the customer's PDF, so an amount without one is
      * refused — and in the Default group, so that even a draft cannot store the pair half-set.
      */
     public function testTotalDiscountRequiresALabel(): void
     {
         $booking = new AccommodationBooking();
-        $booking->setTotalDiscount(5);
+        $booking->setTotalDiscountAmount(5000);
 
         $violations = $this->validate($booking, ['Default']);
 
@@ -91,17 +91,17 @@ class AccommodationBookingTypeTest extends TestCase
     public function testALabelledTotalDiscountPassesValidation(): void
     {
         $booking = new AccommodationBooking();
-        $booking->setTotalDiscount(5);
+        $booking->setTotalDiscountAmount(5000);
         $booking->setTotalDiscountLabel('Treuerabatt');
 
         self::assertCount(0, $this->validate($booking, ['Default']));
     }
 
     /**
-     * The reverse is harmless — without a percentage the label never reaches a breakdown row —
+     * The reverse is harmless — without an amount the label never reaches a breakdown row —
      * so it is deliberately left valid rather than blocking a half-typed edit.
      */
-    public function testALabelWithoutAPercentageIsAccepted(): void
+    public function testALabelWithoutAnAmountIsAccepted(): void
     {
         $booking = new AccommodationBooking();
         $booking->setTotalDiscountLabel('Treuerabatt');

tests/Service/AccommodationBookingBreakdownCalculatorTest.php

@@ -101,33 +101,32 @@ class AccommodationBookingBreakdownCalculatorTest extends TestCase
 
     /**
      * On its own the total discount has nothing to sit below, so no subtotal row is offered and
-     * the percentage applies to the plain total.
+     * the amount comes straight off the plain total.
      */
     public function testTotalDiscountAloneAppliesToTheTotalWithoutASubtotal(): void
     {
         $booking = new AccommodationBooking();
-        $booking->setTotalDiscount(10);
+        $booking->setTotalDiscountAmount(1235);
         $booking->setTotalDiscountLabel('Treuerabatt');
 
         $breakdown = $this->createCalculator()->withDiscounts($booking, $this->breakdown());
 
         self::assertSame([], $breakdown['discounts']);
-        self::assertSame(['label' => 'Treuerabatt', 'percent' => 10, 'amount' => 1235], $breakdown['totalDiscountDetails']);
+        self::assertSame(['label' => 'Treuerabatt', 'amount' => 1235], $breakdown['totalDiscountDetails']);
         self::assertNull($breakdown['discountSubtotal']);
         self::assertSame(12345 - 1235, $breakdown['discountedTotal']);
     }
 
     /**
-     * The worked example from the specification: the total discount compounds on the subtotal
+     * The worked example from the specification: a fixed 50,00 € off the 930,00 € left by the
-     * left by the section discounts, not on the gross total — 5 % of 930,00 € is 46,50 €, where
+     * section discounts, which is where the Zwischensumme row comes from.
-     * 5 % of the gross 1.000,00 € would have been 50,00 €.
      */
-    public function testTotalDiscountCompoundsOnTheSubtotalAfterSectionDiscounts(): void
+    public function testTotalDiscountIsSubtractedFromTheSubtotalAfterSectionDiscounts(): void
     {
         $booking = new AccommodationBooking();
         $booking->setAccommodationDiscount(10);
         $booking->setBoardServiceDiscount(5);
-        $booking->setTotalDiscount(5);
+        $booking->setTotalDiscountAmount(5000);
         $booking->setTotalDiscountLabel('Treuerabatt');
 
         $breakdown = $this->createCalculator()->withDiscounts($booking, [
@@ -138,14 +137,30 @@ class AccommodationBookingBreakdownCalculatorTest extends TestCase
 
         // accommodation: 60000*10% = 6000, board: 20000*5% = 1000 → subtotal 93000
         self::assertSame(93000, $breakdown['discountSubtotal']);
-        self::assertSame(['label' => 'Treuerabatt', 'percent' => 5, 'amount' => 4650], $breakdown['totalDiscountDetails']);
+        self::assertSame(['label' => 'Treuerabatt', 'amount' => 5000], $breakdown['totalDiscountDetails']);
-        self::assertSame(88350, $breakdown['discountedTotal']);
+        self::assertSame(88000, $breakdown['discountedTotal']);
+    }
+
+    /**
+     * A sum larger than the price is clamped rather than refused: prices move after the discount
+     * was agreed, and a negative total would be worse than a free stay.
+     */
+    public function testTotalDiscountLargerThanTheSubtotalIsClampedToIt(): void
+    {
+        $booking = new AccommodationBooking();
+        $booking->setTotalDiscountAmount(20000);
+        $booking->setTotalDiscountLabel('Treuerabatt');
+
+        $breakdown = $this->createCalculator()->withDiscounts($booking, $this->breakdown());
+
+        self::assertSame(['label' => 'Treuerabatt', 'amount' => 12345], $breakdown['totalDiscountDetails']);
+        self::assertSame(0, $breakdown['discountedTotal']);
     }
 
     public function testTotalDiscountThatAmountsToNothingIsSkipped(): void
     {
         $booking = new AccommodationBooking();
-        $booking->setTotalDiscount(20);
+        $booking->setTotalDiscountAmount(2000);
         $booking->setTotalDiscountLabel('Treuerabatt');
 
         $breakdown = $this->createCalculator()->withDiscounts($booking, ['total' => 0]);