Keeps initial product quantity unchanged

Previously, the product quantity was being decreased as new sales was being created. But the generated product report required to display the original product quantity. After this changes, the original product quantity will remain untouched. A new variable will be introduced to track number of units sold. Available units will be determined on the fly. While editing product, the price and quantity can not be modified after more than 1 units has been sold.
dipu-bd · Jun 10, 2021 · 19738a5 · 19738a5
1 parent 799cb72
commit 19738a5
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Showing 17 changed files with 167 additions and 127 deletions.
diff --git a/lib/src/blocs/repository.dart b/lib/src/blocs/repository.dart
@@ -142,8 +142,8 @@ class Repository {
     final doc = _products.doc(sales.productId);
     return doc.get().then((snapshot) {
       final product = snapshot.data()!;
-      assert(product.quantity >= sales.quantity);
-      doc.update({'quantity': product.quantity - sales.quantity});
+      assert(product.availableUnits >= sales.quantity);
+      doc.update({'units_sold': product.unitsSold + sales.quantity});
       return _sales.add(sales);
     });
   }

diff --git a/lib/src/models/product.dart b/lib/src/models/product.dart
@@ -6,15 +6,21 @@ export 'package:sales_tracker/src/models/item.dart';
 class Product extends Item {
   late final String name;
   late final double unitCost;
+  late final int unitsSold;
 
-  double get cost => quantity * unitCost;
+  double get totalCost => quantity * unitCost;
+
+  int get availableUnits => quantity - unitsSold;
+
+  double get availableCost => availableUnits * unitCost;
 
   Product({
     required this.name,
     required this.unitCost,
     required int quantity,
     required DateTime date,
-  }) : super(
+  })  : unitsSold = 0,
+        super(
           date: date,
           quantity: quantity,
         );
@@ -23,18 +29,26 @@ class Product extends Item {
       : super.fromJson(id, data) {
     name = data.remove('name');
     unitCost = data.remove('unit_price');
+    unitsSold = data.remove('units_sold') ?? 0;
   }
 
   Map<String, dynamic> toJson() {
     final data = super.toJson();
     data['name'] = name;
     data['unit_price'] = unitCost;
+    data['units_sold'] = unitsSold;
     return data;
   }
 }
 
 extension ProductFormat on Product {
+  String get unitsSoldStr => unitsSold.toString();
+
+  String get availableUnitsStr => availableUnits.toString();
+
   String get unitCostStr => formatCurrency(unitCost);
 
-  String get costStr => formatCurrency(cost);
+  String get totalCostStr => formatCurrency(totalCost);
+
+  String get availableCostStr => formatCurrency(availableCost);
 }
diff --git a/lib/src/models/product_report.dart b/lib/src/models/product_report.dart
@@ -5,8 +5,11 @@ import 'package:sales_tracker/src/utils/formatters.dart';
 export 'package:sales_tracker/src/models/report.dart';
 
 class ProductReport extends Report<Product> {
+  late final int totalSold;
   late final double totalCost;
 
+  int get remainingUnits => totalUnits - totalSold;
+
   ProductReport({
     required DateTime startTime,
     required DateTime endTime,
@@ -16,11 +19,14 @@ class ProductReport extends Report<Product> {
           endTime: endTime,
           items: products,
         ) {
+    int sold = 0;
     double cost = 0;
     for (final item in products) {
-      cost += item.cost;
+      sold += item.unitsSold;
+      cost += item.totalCost;
     }
     totalCost = cost;
+    totalSold = sold;
   }
 }
 

diff --git a/lib/src/models/report.dart b/lib/src/models/report.dart
@@ -6,7 +6,7 @@ class Report<T extends Item> {
   final DateTime endTime;
   final List<T> items;
   final Map<DateTime, List<T>> groups = {};
-  late final int totalItems;
+  late final int totalUnits;
 
   Report({
     required this.items,
@@ -28,7 +28,7 @@ class Report<T extends Item> {
       groups.putIfAbsent(group, () => []);
       groups[group]!.add(item);
     }
-    totalItems = total;
+    totalUnits = total;
   }
 }
 

diff --git a/lib/src/models/sales_record.dart b/lib/src/models/sales_record.dart
@@ -7,26 +7,26 @@ export 'package:sales_tracker/src/models/item.dart';
 class SalesRecord extends Item {
   late final String productId;
   late final String productName;
-  late final double unitBuyPrice;
-  late final double unitSellPrice;
+  late final double unitCost;
+  late final double unitPrice;
 
-  double get buyingPrice => quantity * unitBuyPrice;
+  double get totalCost => quantity * unitCost;
 
-  double get sellingPrice => quantity * unitSellPrice;
+  double get totalPrice => quantity * unitPrice;
 
-  double get profit => sellingPrice - buyingPrice;
+  double get profit => totalPrice - totalCost;
 
-  double get profitPerUnit => (sellingPrice - buyingPrice) / quantity;
+  double get profitPerUnit => (totalPrice - totalCost) / quantity;
 
   SalesRecord({
     required Product product,
-    required this.unitSellPrice,
+    required this.unitPrice,
     required int quantity,
     required DateTime date,
   })  : assert(product.id != null),
         productId = product.id!,
         productName = product.name,
-        unitBuyPrice = product.unitCost,
+        unitCost = product.unitCost,
         super(
           date: date,
           quantity: quantity,
@@ -36,28 +36,28 @@ class SalesRecord extends Item {
       : super.fromJson(id, data) {
     productId = data.remove('product_id');
     productName = data.remove('product_name');
-    unitBuyPrice = data.remove('buy_price');
-    unitSellPrice = data.remove('sell_price');
+    unitCost = data.remove('buy_price') ?? 0;
+    unitPrice = data.remove('sell_price') ?? 0;
   }
 
   Map<String, dynamic> toJson() {
     final data = super.toJson();
     data['product_id'] = productId;
     data['product_name'] = productName;
-    data['buy_price'] = unitBuyPrice;
-    data['sell_price'] = unitSellPrice;
+    data['buy_price'] = unitCost;
+    data['sell_price'] = unitPrice;
     return data;
   }
 }
 
 extension SalesRecordFormat on SalesRecord {
-  String get unitBuyPriceStr => formatCurrency(unitBuyPrice);
+  String get unitCostStr => formatCurrency(unitCost);
 
-  String get unitSellPriceStr => formatCurrency(unitSellPrice);
+  String get unitPriceStr => formatCurrency(unitPrice);
 
-  String get buyingPriceStr => formatCurrency(buyingPrice);
+  String get totalCostStr => formatCurrency(totalCost);
 
-  String get sellingPriceStr => formatCurrency(sellingPrice);
+  String get totalPriceStr => formatCurrency(totalPrice);
 
   String get profitStr => formatCurrency(profit);
 

diff --git a/lib/src/models/sales_report.dart b/lib/src/models/sales_report.dart
@@ -22,8 +22,8 @@ class SalesReport extends Report<SalesRecord> {
     double cost = 0;
     double price = 0;
     for (final record in sales) {
-      cost += record.buyingPrice;
-      price += record.sellingPrice;
+      cost += record.totalCost;
+      price += record.totalPrice;
     }
     totalCost = cost;
     totalPrice = price;

diff --git a/lib/src/pages/widgets/home_page_drawer.dart b/lib/src/pages/widgets/home_page_drawer.dart
@@ -77,7 +77,9 @@ class HomePageDrawer extends StatelessWidget {
 
   Widget buildUserName() {
     final user = FirebaseAuth.instance.currentUser;
-    if (user?.displayName == null) return Container();
+    if (user?.displayName == null) {
+      return Container();
+    }
     return Text(
       user!.displayName!,
       textAlign: TextAlign.center,
@@ -133,7 +135,7 @@ class HomePageDrawer extends StatelessWidget {
       ),
       onTap: () async {
         await SalesReportPage.display(context);
-        Navigator.of(context).pop();
+        Navigator.of(context, rootNavigator: true).pop();
       },
     );
   }
@@ -146,9 +148,9 @@ class HomePageDrawer extends StatelessWidget {
       shape: RoundedRectangleBorder(
         borderRadius: BorderRadius.circular(5),
       ),
-      onTap: () {
-        Navigator.of(context).pop();
-        ProductFormDialog.display(context);
+      onTap: () async {
+        await ProductFormDialog.display(context);
+        Navigator.of(context, rootNavigator: true).pop();
       },
     );
   }
@@ -173,13 +175,15 @@ class HomePageDrawer extends StatelessWidget {
               TextButton(
                 child: Text('Continue'),
                 onPressed: () {
-                  Navigator.of(context).pop();
                   Repository.of(context).clearAllData();
+                  Navigator.of(context).pop();
                 },
               ),
               TextButton(
                 child: Text('Cancel'),
-                onPressed: () => Navigator.of(context).pop(),
+                onPressed: () {
+                  Navigator.of(context, rootNavigator: true).pop();
+                },
               ),
             ],
           ),

diff --git a/lib/src/pages/widgets/product_form_dialog.dart b/lib/src/pages/widgets/product_form_dialog.dart
@@ -6,8 +6,8 @@ import 'package:sales_tracker/src/models/product.dart';
 import 'package:sales_tracker/src/pages/widgets/error_message.dart';
 
 class ProductFormDialog extends StatelessWidget {
-  static void display(BuildContext context, [Product? product]) {
-    Navigator.of(context).push(
+  static Future<void> display(BuildContext context, [Product? product]) {
+    return Navigator.of(context, rootNavigator: true).push(
       MaterialPageRoute(
         maintainState: false,
         fullscreenDialog: true,
@@ -31,7 +31,7 @@ class ProductFormDialog extends StatelessWidget {
     unitPriceInput = TextEditingController(text: product?.unitCost.toString());
     quantityInput = TextEditingController(text: product?.quantity.toString());
     dateInput = TextEditingController(
-      text: product?.date != null ? _dateFormatter.format(product!.date) : '',
+      text: _dateFormatter.format(product?.date ?? DateTime.now()),
     );
   }
 
@@ -119,11 +119,12 @@ class ProductFormDialog extends StatelessWidget {
 
   Widget buildUnitPriceInput(BuildContext context) {
     return TextField(
+      enabled: product == null || product!.unitsSold == 0,
       controller: unitPriceInput,
       keyboardType: TextInputType.number,
       textInputAction: TextInputAction.next,
       decoration: InputDecoration(
-          labelText: 'Cost Per Unit',
+        labelText: 'Cost Per Unit',
       ),
       onEditingComplete: () {
         FocusScope.of(context).nextFocus();
@@ -142,6 +143,7 @@ class ProductFormDialog extends StatelessWidget {
 
   Widget buildQuantityInput(BuildContext context) {
     return TextField(
+      enabled: product == null || product!.unitsSold == 0,
       controller: quantityInput,
       keyboardType: TextInputType.number,
       textInputAction: TextInputAction.next,

diff --git a/lib/src/pages/widgets/product_item.dart b/lib/src/pages/widgets/product_item.dart
@@ -32,7 +32,7 @@ class ProductItemTile extends StatelessWidget {
         buildDeleteAction(context),
         buildEditAction(context),
       ],
-      secondaryActions: product.quantity > 0
+      secondaryActions: product.availableUnits > 0
           ? <Widget>[
               buildSaleAction(context),
             ]
@@ -71,7 +71,7 @@ class ProductItemTile extends StatelessWidget {
     return CircleAvatar(
       backgroundColor: Colors.grey.shade300,
       child: Text(
-        '${product.quantity > 99 ? '99+' : product.quantity}',
+        '${product.availableUnits > 99 ? '99+' : product.availableUnits}',
         style: TextStyle(
           fontFamily: 'monospace',
           fontWeight: FontWeight.bold,
@@ -98,21 +98,28 @@ class ProductItemTile extends StatelessWidget {
 
   Widget buildPrice() {
     return Container(
-      constraints: BoxConstraints(
-        minWidth: 75,
-      ),
+      // constraints: BoxConstraints(
+      //   minWidth: 75,
+      // ),
       child: Column(
         mainAxisSize: MainAxisSize.min,
         children: [
           Text(
-            product.costStr,
+            product.unitCostStr,
             style: TextStyle(
               fontSize: 15,
               fontWeight: FontWeight.bold,
             ),
           ),
+          // Text(
+          //   '${product.availableUnits} × ${product.unitCostStr}',
+          //   style: TextStyle(
+          //     fontSize: 12,
+          //     color: Colors.grey,
+          //   ),
+          // ),
           Text(
-            '${product.quantity} × ${product.unitCostStr}',
+            'per unit',
             style: TextStyle(
               fontSize: 12,
               color: Colors.grey,
@@ -124,7 +131,7 @@ class ProductItemTile extends StatelessWidget {
   }
 
   void _saleProduct(BuildContext context) {
-    if (product.quantity > 0) {
+    if (product.availableUnits > 0) {
       SaleFormDialog.display(context, product);
     }
   }

diff --git a/lib/src/pages/widgets/product_report_view.dart b/lib/src/pages/widgets/product_report_view.dart
@@ -10,7 +10,7 @@ class ProductReportView extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    if (report.totalItems == 0) {
+    if (report.totalUnits == 0) {
       return buildEmptyMessage();
     }
 
@@ -28,10 +28,9 @@ class ProductReportView extends StatelessWidget {
     children += [
       Divider(height: 1),
       SizedBox(height: 10),
-      buildItemRow(
-          'Total Products', '${report.items.length}', Colors.grey[700]),
+      buildItemRow('Products', '${report.items.length}', Colors.grey[700]),
       SizedBox(height: 10),
-      buildItemRow('Total Quantity', '${report.totalItems}', Colors.grey[700]),
+      buildItemRow('Total Units', '${report.totalUnits}', Colors.grey[700]),
       SizedBox(height: 10),
       Divider(height: 1),
       SizedBox(height: 10),
@@ -106,7 +105,7 @@ class ProductReportView extends StatelessWidget {
         ),
         Text(' = '),
         Text(
-          product.costStr.padRight(10, ' '),
+          product.totalCostStr.padRight(10, ' '),
           style: TextStyle(
             fontFamily: 'monospace',
             fontSize: 12,

diff --git a/lib/src/pages/widgets/report_page_widget.dart b/lib/src/pages/widgets/report_page_widget.dart
@@ -66,7 +66,7 @@ class ReportPageWidget<T extends Report> extends StatelessWidget {
   }
 
   Widget buildSaveAsPdfButton(BuildContext context, T report) {
-    if (report.totalItems == 0) {
+    if (report.totalUnits == 0) {
       return Container();
     }
     return ListTile(