Refactor stock adjustment actions

- Handle timeout
- Handle error

lib/inventree/stock.dart

@@ -1,4 +1,5 @@
 import 'package:InvenTree/inventree/part.dart';
+import 'package:InvenTree/widget/dialogs.dart';
 import 'package:flutter/cupertino.dart';
 import 'package:http/http.dart' as http;
 import 'model.dart';
@@ -391,51 +392,81 @@ class InvenTreeStockItem extends InvenTreeModel {
     return item;
   }
 
-  Future<http.Response> countStock(double quan, {String notes}) async {
+  /*
+   * Perform stocktake action:
+   *
+   * - Add
+   * - Remove
+   * - Count
+   */
+  Future<bool> adjustStock(BuildContext context, String endpoint, double q, {String notes}) async {
 
-    // Cannot 'count' a serialized StockItem
+    // Serialized stock cannot be adjusted
     if (isSerialized()) {
-      return null;
+      return false;
     }
 
-    // Cannot count negative stock
+    // Cannot handle negative stock
-    if (quan < 0) {
+    if (q < 0) {
-      return null;
+      return false;
     }
 
-    return api.post("/stock/count/", body: {
+    var response = await api.post(
-      "item": {
+      endpoint,
-        "pk": "${pk}",
+      body: {
-        "quantity": "${quan}",
+        "item": {
-      },
+          "pk": "${pk}",
-      "notes": notes ?? '',
+          "quantity": "${q}",
+        },
+        "notes": notes ?? '',
+    }).timeout(Duration(seconds: 10)).catchError((error) {
+      if (error is TimeoutException) {
+        showTimeoutError(context);
+      } else if (error is SocketException) {
+        showServerError(
+            context,
+            I18N.of(context).connectionRefused,
+            error.toString()
+        );
+      } else {
+        // Re-throw the error, let sentry handle it!
+        throw error;
+      }
+
+      // Null response if error
+      return null;
     });
+
+    if (response == null) return false;
+
+    if (response.statusCode != 200) {
+      showStatusCodeError(context, response.statusCode);
+      return false;
+    }
+
+    // Stock adjustment succeeded!
+    return true;
   }
 
-  Future<http.Response> addStock(double quan, {String notes}) async {
+  Future<bool> countStock(BuildContext context, double q, {String notes}) async {
 
-    if (isSerialized() || quan <= 0) return null;
+    final bool result = await adjustStock(context, "/stock/count", q, notes: notes);
 
-    return api.post("/stock/add/", body: {
+    return result;
-      "item": {
-        "pk": "${pk}",
-        "quantity": "${quan}",
-      },
-      "notes": notes ?? '',
-    });
   }
 
-  Future<http.Response> removeStock(double quan, {String notes}) async {
+  Future<bool> addStock(BuildContext context, double q, {String notes}) async {
 
-    if (isSerialized() || quan <= 0) return null;
+    final bool result = await adjustStock(context,  "/stock/add/", q, notes: notes);
 
-    return api.post("/stock/remove/", body: {
+    return result;
-      "item": {
+  }
-        "pk": "${pk}",
+
-        "quantity": "${quan}",
+  Future<bool> removeStock(BuildContext context, double q, {String notes}) async {
-      },
+
-      "notes": notes ?? '',
+    final bool result = await adjustStock(context, "/stock/remove/", q, notes: notes);
-    });
+
+    return result;
   }
 
   Future<http.Response> transferStock(int location, {double quantity, String notes}) async {

lib/widget/stock_detail.dart

@@ -70,13 +70,11 @@ class _StockItemDisplayState extends RefreshableState<StockDetailWidget> {
     double quantity = double.parse(_quantityController.text);
     _quantityController.clear();
 
-    // Await response to prevent the button from being pressed multiple times
+    final bool result = await item.addStock(context, quantity, notes: _notesController.text);
-    var response = await item.addStock(quantity, notes: _notesController.text);
     _notesController.clear();
 
-    _stockUpdateMessage(response);
+    _stockUpdateMessage(result);
 
-    // TODO - Handle error cases
     refresh();
   }
 
@@ -111,20 +109,27 @@ class _StockItemDisplayState extends RefreshableState<StockDetailWidget> {
     );
   }
 
+  void _stockUpdateMessage(bool result) {
+
+    showSnackIcon(
+      refreshableKey,
+      result ? "Stock item updated" : "Stock item updated failed",
+      success: result
+    );
+  }
+
   void _removeStock() async {
     Navigator.of(context).pop();
 
     double quantity = double.parse(_quantityController.text);
     _quantityController.clear();
 
-    var response = await item.removeStock(quantity, notes: _notesController.text);
+    final bool result = await item.removeStock(context, quantity, notes: _notesController.text);
-    _notesController.clear();
 
-    // TODO - Handle error cases
+    _stockUpdateMessage(result);
 
     refresh();
 
-    // TODO - Display a snackbar here indicating the action was successful (or otherwise)
   }
 
   void _removeStockDialog() {
@@ -166,19 +171,16 @@ class _StockItemDisplayState extends RefreshableState<StockDetailWidget> {
     double quantity = double.parse(_quantityController.text);
     _quantityController.clear();
 
-    var response = await item.countStock(quantity, notes: _notesController.text);
+    final bool result = await item.countStock(context, quantity, notes: _notesController.text);
-    _notesController.clear();
 
-    // TODO - Handle error cases, timeout, etc
+    _stockUpdateMessage(result);
 
     refresh();
-
-    // TODO - Display a snackbar here indicating the action was successful (or otherwise)
   }
 
   void _countStockDialog() async {
 
-    _quantityController.text = item.quantity.toString();
+    _quantityController.text = item.quantityString;
     _notesController.clear();
 
     showFormDialog(context, I18N.of(context).countStock,
@@ -194,7 +196,7 @@ class _StockItemDisplayState extends RefreshableState<StockDetailWidget> {
       fields: <Widget> [
         QuantityField(
           label: I18N.of(context).countStock,
-          hint: "${item.quantity}",
+          hint: "${item.quantityString}",
           controller: _quantityController,
         ),
         TextFormField(
@@ -233,7 +235,7 @@ class _StockItemDisplayState extends RefreshableState<StockDetailWidget> {
 
     InvenTreeStockLocation selectedLocation;
 
-    _quantityController.text = "${item.quantity}";
+    _quantityController.text = "${item.quantityString}";
 
     showFormDialog(context, I18N.of(context).transferStock,
         key: _moveStockKey,
@@ -385,7 +387,7 @@ class _StockItemDisplayState extends RefreshableState<StockDetailWidget> {
           ListTile(
             title: Text(I18N.of(context).quantity),
             leading: FaIcon(FontAwesomeIcons.cubes),
-            trailing: Text("${item.quantity}"),
+            trailing: Text("${item.quantityString}"),
           )
       );
     }