Restore form when form submit fails due to error

counter/static/bundled/counter/counter-click-index.ts

@@ -2,12 +2,19 @@ import { exportToHtml } from "#core:utils/globals";
 
 const quantityForTrayPrice = 6;
 
+interface InitialFormData {
+  /* Used to refill the form when the backend raises an error */
+  id?: string;
+  quantity?: number;
+}
+
 interface CounterConfig {
   csrfToken: string;
   clickApiUrl: string;
   customerBalance: number;
   customerId: number;
   products: Record<string, Product>;
+  formInitial: InitialFormData[];
 }
 
 interface Product {
@@ -48,8 +55,16 @@ exportToHtml("loadCounter", (config: CounterConfig) => {
       codeField: undefined,
 
       init() {
+        // Fill the basket with the initial data
+        for (const entry of config.formInitial) {
+          if (entry.id !== undefined && entry.quantity !== undefined) {
+            this.addToBasket(entry.id, entry.quantity);
+          }
+        }
+
         this.codeField = this.$refs.codeField;
         this.codeField.widget.focus();
+
         // It's quite tricky to manually apply attributes to the management part
         // of a formset so we dynamically apply it here
         this.$refs.basketManagementForm

counter/templates/counter/counter_click.jinja

@@ -169,21 +169,36 @@
   {{ super() }}
   <script>
     const products = {
-      {%- for p in products -%}
-        {{ p.id }}: {
-          id: "{{ p.id }}",
-          name: "{{ p.name }}",
-          price: {{ p.price }},
-          hasTrayPrice: {{ p.tray | tojson }},
+      {%- for product in products -%}
+        {{ product.id }}: {
+          id: "{{ product.id }}",
+          name: "{{ product.name }}",
+          price: {{ product.price }},
+          hasTrayPrice: {{ product.tray | tojson }},
         },
       {%- endfor -%}
     };
+    const formInitial = [
+      {%- for f in form -%}
+        {%- if f.cleaned_data -%}
+          {
+            {%- if f.cleaned_data["id"] -%}
+              id: '{{ f.cleaned_data["id"] | tojson }}',
+            {%- endif -%}
+            {%- if f.cleaned_data["quantity"] -%}
+              quantity: {{ f.cleaned_data["quantity"] | tojson }},
+            {%- endif -%}
+          },
+        {%- endif -%}
+      {%- endfor -%}
+    ];
     window.addEventListener("DOMContentLoaded", () => {
       loadCounter({
         csrfToken: "{{ csrf_token }}",
         clickApiUrl: "{{ url('counter:click', counter_id=counter.id, user_id=customer.user.id) }}", customerBalance: {{ customer.amount }},
         products: products,
         customerId: {{ customer.pk }},
+        formInitial: formInitial,
       });
     });
   </script>

counter/views/click.py

@@ -117,12 +117,16 @@ class BaseBasketForm(BaseFormSet):
         super().clean()
         if len(self) == 0:
             return
-        if len(self.errors) > 0:
-            return
 
+        self._check_forms_have_errors()
         self._check_recorded_products(self[0].customer)
         self._check_enough_money(self[0].counter, self[0].customer)
 
+    def _check_forms_have_errors(self):
+        for form in self:
+            if len(form.errors):
+                raise ValidationError(_("Submmited basket is invalid"))
+
     def _check_enough_money(self, counter: Counter, customer: Customer):
         self.total_price = sum([data["total_price"] for data in self.cleaned_data])
         if self.total_price > customer.amount: