feat: arithmetic calc price function

src/utils/arithmetic.ts

@@ -1,4 +1,63 @@
+import { storeToRefs } from 'pinia';
+import { useConfigStore } from 'src/stores/config';
+
+const configStore = useConfigStore();
+const { data: config } = storeToRefs(configStore);
+
 export function precisionRound(number: number, precision = 2) {
-  var factor = Math.pow(10, precision);
+  const factor = Math.pow(10, precision);
   return Math.round(number * factor) / factor;
 }
+
+export function calculatePrice(
+  data: {
+    price: number;
+    vat?: number;
+    discount?: number;
+    amount?: number;
+    calcVat?: boolean;
+    vatIncluded?: boolean;
+    output: 'vat' | 'total' | 'beforeVat';
+  } = {
+    price: 0,
+    vat: 0.07,
+    discount: 0,
+    amount: 1,
+    calcVat: false,
+    vatIncluded: false,
+    output: 'total',
+  },
+) {
+  const {
+    price,
+    vat = config.value?.vat || 0.07,
+    discount = 0,
+    amount = 1,
+    calcVat = false,
+    vatIncluded = false,
+    output = 'total',
+  } = data;
+
+  // Calculate VAT
+  const calculatedVat = calcVat
+    ? precisionRound((price * amount - discount) * vat)
+    : 0;
+
+  // Calculate total
+  const total = precisionRound(
+    price * amount -
+      discount +
+      precisionRound(
+        calcVat ? price * (discount ? amount : 1) - discount * vat : 0,
+      ),
+  );
+
+  // Calculate before VAT
+  const beforeVat = vatIncluded ? precisionRound(price / (1 + vat)) : price;
+
+  // Return based on output selection
+  if (output === 'vat') return calculatedVat;
+  if (output === 'total') return total;
+  if (output === 'beforeVat') return beforeVat;
+  return 0;
+}