initial booking

src/lib/money.ts

@@ -0,0 +1,33 @@
+// Price math in öre (1 SEK = 100 öre) to avoid float drift.
+
+export function formatOre(ore: number, locale: 'sv' | 'en' = 'sv'): string {
+  const sek = ore / 100;
+  return new Intl.NumberFormat(locale === 'sv' ? 'sv-SE' : 'en-SE', {
+    style: 'currency',
+    currency: 'SEK',
+    minimumFractionDigits: 2,
+    maximumFractionDigits: 2,
+  }).format(sek);
+}
+
+export function vatAmountOre(netOre: number, vatBp: number): number {
+  return Math.round((netOre * vatBp) / 10000);
+}
+
+/** Net price + VAT, rounded the same way as billing. */
+export function priceInclVatOre(netOre: number, vatBp: number): number {
+  return netOre + vatAmountOre(netOre, vatBp);
+}
+
+export function computeTotals(
+  items: Array<{ unitPriceOre: number; quantity: number; vatBp: number }>,
+) {
+  let subtotal = 0;
+  let vat = 0;
+  for (const i of items) {
+    const line = i.unitPriceOre * i.quantity;
+    subtotal += line;
+    vat += vatAmountOre(line, i.vatBp);
+  }
+  return { subtotalOre: subtotal, vatOre: vat, totalOre: subtotal + vat };
+}