add latest price autocomplete

lib/api.dart

@@ -184,6 +184,19 @@ class API {
     return resp.map((x) => Price(x)).toList();
   }
 
+  Future<Price> getLatestPrice(String item, String variant,
+      {String? origin}) async {
+    var url = "$instance/item/$item/$variant/price_latest";
+
+    if (origin != null) {
+      url += "?origin=$origin";
+    }
+
+    var resp = jsonDecode(await getRequest(url)) as Map<String, dynamic>;
+
+    return Price(resp);
+  }
+
   // Flows
 
   // /flows

lib/pages/supply.dart

@@ -98,8 +98,11 @@ class _SupplyPageState extends State<SupplyPage> {
                             .contains(textEditingValue.text.toLowerCase());
                       });
                     },
-                    onSelected: (String selection) {
+                    onSelected: (String selection) async {
+                      var price =
+                          await API().getLatestPrice(widget.item.id, variant);
                       setState(() {
+                        _price = price.value.toStringAsFixed(2);
                         _selectedOrigin = selection;
                       });
                     },