feat(ui): add original price display for rebated products

src/components/ProductDetailPage.js

@@ -713,6 +713,16 @@ class ProductDetailPage extends Component {
       currency: "EUR",
     }).format(product.price);
 
+    let originalPriceWithTax = null;
+    if (product.rebate && product.rebate > 0) {
+      const rebatePct = product.rebate / 100;
+      const originalPrice = Math.round((product.price / (1 - rebatePct)) * 10) / 10;
+      originalPriceWithTax = new Intl.NumberFormat("de-DE", {
+        style: "currency",
+        currency: "EUR",
+      }).format(originalPrice);
+    }
+
     return (
       <Container
         maxWidth="lg"
@@ -952,6 +962,20 @@ class ProductDetailPage extends Component {
                     color="primary"
                     sx={{ fontWeight: "bold" }}
                   >
+                    {originalPriceWithTax && (
+                      <Typography
+                        component="span"
+                        variant="h6"
+                        sx={{
+                          textDecoration: 'line-through',
+                          color: 'text.secondary',
+                          mr: 1,
+                          display: 'inline-block'
+                        }}
+                      >
+                        {originalPriceWithTax}
+                      </Typography>
+                    )}
                     {priceWithTax}
                   </Typography>
                   <Typography variant="body2" color="text.secondary">