feat(ADM-018): completed feature

project/src/modules/pricing/domain/errors.ts

@@ -0,0 +1,13 @@
+export class PriceNotFoundError extends Error {
+  constructor() {
+    super('Variant price not found');
+    this.name = 'PriceNotFoundError';
+  }
+}
+
+export class InvalidPriceError extends Error {
+  constructor(message = 'Invalid price command') {
+    super(message);
+    this.name = 'InvalidPriceError';
+  }
+}

project/src/modules/pricing/domain/ports.ts

@@ -0,0 +1,17 @@
+import type {
+  PriceCalculation,
+  PriceCalculationCommand,
+  SetVariantPriceCommand,
+  VariantPrice,
+} from './price.js';
+
+export interface PricingService {
+  calculate(input: PriceCalculationCommand): Promise<PriceCalculation>;
+  getVariantPrice(variantId: string): Promise<VariantPrice | undefined>;
+  setVariantPrice(input: SetVariantPriceCommand): Promise<VariantPrice>;
+}
+
+export interface PricingRepository {
+  findByVariantId(variantId: string): Promise<VariantPrice | undefined>;
+  setVariantPrice(input: SetVariantPriceCommand): Promise<VariantPrice>;
+}

project/src/modules/pricing/domain/price.ts

@@ -0,0 +1,46 @@
+export type VatRate = 'general' | 'reduced';
+
+export const VAT_BASIS_POINTS: Record<VatRate, number> = {
+  general: 2100,
+  reduced: 1000,
+};
+
+export interface VariantPrice {
+  variantId: string;
+  netUnitAmountCents: number;
+  offerCents: number | null;
+  costCents: number | null;
+  vatRate: VatRate;
+  currency: 'EUR';
+  createdAt: Date;
+  updatedAt: Date;
+}
+
+export interface SetVariantPriceCommand {
+  variantId: string;
+  netUnitAmountCents: number;
+  offerCents?: number | null;
+  costCents?: number | null;
+  vatRate: VatRate;
+}
+
+export interface PriceCalculationCommand {
+  variantId: string;
+  quantity: number;
+}
+
+export interface PriceCalculation {
+  variantId: string;
+  quantity: number;
+  currency: 'EUR';
+  vatRate: VatRate;
+  vatBasisPoints: number;
+  netUnitAmountCents: number;
+  netSubtotalCents: number;
+  vatAmountCents: number;
+  totalCents: number;
+}
+
+export function calculateVatAmountCents(netSubtotalCents: number, vatRate: VatRate): number {
+  return Math.round((netSubtotalCents * VAT_BASIS_POINTS[vatRate]) / 10_000);
+}