Analytics: queued events, once-per-order revenue, heatmap on product pages (#17)

Analytics: queued events, once-per-order revenue, heatmap on product pages (#17)
Co-authored-by: Michael Czechowski <mail@librete.ch>

pages/checkout/result/[uuid].vue

@@ -151,6 +151,23 @@ onMounted(async () => {
 					orderTotal: order.value.total,
 					itemCount: order.value.cart?.length ?? 0
 				});
+
+				// Revenue for Umami's revenue report: exactly once per order, even if the
+				// customer reloads this page or opens it again from the confirmation mail.
+				const purchaseKey = `mp-purchase-tracked-${order.value.uuid}`;
+				if (!localStorage.getItem(purchaseKey)) {
+					const products = (order.value.cart ?? []).map((item) => item.product?.slug).filter(Boolean);
+					trackEvent(
+						"purchase-completed",
+						{
+							revenue: order.value.total,
+							currency: "EUR",
+							itemCount: (order.value.cart ?? []).reduce((sum, item) => sum + (item.count ?? 1), 0),
+							products: products.join(",").slice(0, 400)
+						},
+						() => localStorage.setItem(purchaseKey, new Date().toISOString())
+					);
+				}
 			}
 
 			if (order.value?.invoice?.url) {