Bug fix and refactoring

- Display difference between "in stock" and "unallocated stock"
- Refactor to use single function in detail and list widgets

lib/inventree/part.dart

@@ -269,17 +269,18 @@ class InvenTreePart extends InvenTreeModel {
     }
 
     // Get the 'available stock' for this Part
-    double get availableStock {
+    double get unallocatedStock {
+
       // Note that the 'available_stock' was not added until API v35
-      if (jsondata.containsKey("available_stock")) {
-        return double.tryParse(jsondata["available_stock"].toString()) ?? 0;
+      if (jsondata.containsKey("unallocated_stock")) {
+        return double.tryParse(jsondata["unallocated_stock"].toString()) ?? 0;
       } else {
         return inStock;
       }
     }
 
-    String get availableStockString {
-      String q = simpleNumberString(availableStock);
+    String get unallocatedStockString {
+      String q = simpleNumberString(unallocatedStock);
 
       if (units.isNotEmpty) {
         q += " ${units}";
@@ -288,6 +289,20 @@ class InvenTreePart extends InvenTreeModel {
       return q;
     }
 
+    String stockString({bool includeUnits = true}) {
+      String q = unallocatedStockString;
+
+      if (unallocatedStock != inStock) {
+        q += " / ${inStockString}";
+      }
+
+      if (includeUnits && units.isNotEmpty) {
+        q += " ${units}";
+      }
+
+      return q;
+    }
+
     String get units => (jsondata["units"] ?? "") as String;
 
     // Get the number of units being build for this Part

lib/widget/part_detail.dart

@@ -209,19 +209,19 @@ class _PartDisplayState extends RefreshableState<PartDetailWidget> {
             subtitle: Text(L10().partCategoryTopLevel),
             leading: FaIcon(FontAwesomeIcons.sitemap, color: COLOR_CLICK),
             onTap: () {
-            Navigator.push(context, MaterialPageRoute(builder: (context) => CategoryDisplayWidget(null)));
+              Navigator.push(context, MaterialPageRoute(
+                  builder: (context) => CategoryDisplayWidget(null)));
             },
           )
       );
     }
 
-    // Stock information
     tiles.add(
       ListTile(
         title: Text(L10().availableStock),
         subtitle: Text(L10().stockDetails),
         leading: FaIcon(FontAwesomeIcons.boxes, color: COLOR_CLICK),
-        trailing: Text(part.availableStockString),
+        trailing: Text(part.stockString()),
         onTap: () {
           setState(() {
             tabIndex = 1;

lib/widget/part_list.dart

@@ -87,7 +87,7 @@ class _PaginatedPartListState extends PaginatedSearchState<PaginatedPartList> {
     return ListTile(
       title: Text(part.fullname),
       subtitle: Text(part.description),
-      trailing: Text(part.availableStockString),
+      trailing: Text(part.stockString()),
       leading: InvenTreeAPI().getImage(
         part.thumbnail,
         width: 40,