feat: implement loading state for checkout process and enhance stepper component

src/app/features/store/pages/checkout-page/checkout-page.component.html

@@ -1,11 +1,17 @@
-<div class="checkout-page">
+@if (isLoadingPurchase()) {
-  <div
+  <div class="checkout-page__loading" role="status" aria-live="polite">
-    class="checkout-page__stepper-col"
+    <span class="checkout-page__spinner" aria-hidden="true"></span>
-    [class.checkout-page__stepper-col--editing]="isEditingItems()"
+    <span>Cargando compra...</span>
-    [attr.aria-hidden]="isEditingItems()"
+  </div>
-    [attr.inert]="isEditingItems() ? '' : null"
+} @else {
-  >
+  <div class="checkout-page">
-    <app-stepper #stepper>
+    <div
+      class="checkout-page__stepper-col"
+      [class.checkout-page__stepper-col--editing]="isEditingItems()"
+      [attr.aria-hidden]="isEditingItems()"
+      [attr.inert]="isEditingItems() ? '' : null"
+    >
+      <app-stepper #stepper [initialStepIndex]="checkoutStepIndex()">
         <app-step label="Datos" [isValid]="isStep1Valid()">
           <app-checkout-data-step
             [form]="form"
@@ -34,32 +40,33 @@
             (retryQrPolling)="retryQrPolling()"
           />
         </app-step>
-    </app-stepper>
+      </app-stepper>
-  </div>
-
-  @if (isEditingItems()) {
-    <div class="checkout-page__editing-notice" role="status">
-      <p>Terminá de modificar las cantidades para continuar con el pago.</p>
     </div>
-  }
 
-  <div class="checkout-page__cart-col">
+    @if (isEditingItems()) {
-    <app-cart
+      <div class="checkout-page__editing-notice" role="status">
-      title="COMPRA"
+        <p>Terminá de modificar las cantidades para continuar con el pago.</p>
-      [items]="mappedCartItems()"
+      </div>
-      [subtotal]="cartSubtotal()"
+    }
-      [discount]="cartDiscount()"
+
-      [total]="cartTotal()"
+    <div class="checkout-page__cart-col">
-      [allowEditing]="
+      <app-cart
-        createdPurchase()?.status === 'created' || createdPurchase()?.status === 'pending_payment'
+        title="COMPRA"
-      "
+        [items]="mappedCartItems()"
-      [allowRemove]="false"
+        [subtotal]="cartSubtotal()"
-      [persistQuantityChanges]="false"
+        [discount]="cartDiscount()"
-      [editing]="isEditingItems()"
+        [total]="cartTotal()"
-      [editingDisabled]="isUpdatingItem() || isPreparingItemEdit()"
+        [allowEditing]="
-      backgroundColor="transparent"
+          createdPurchase()?.status === 'created' || createdPurchase()?.status === 'pending_payment'
-      (editingChange)="onEditingItemsChange($event)"
+        "
-      (itemQuantityChange)="onPurchaseItemQuantityChange($event)"
+        [allowRemove]="false"
-    />
+        [persistQuantityChanges]="false"
+        [editing]="isEditingItems()"
+        [editingDisabled]="isUpdatingItem() || isPreparingItemEdit()"
+        backgroundColor="transparent"
+        (editingChange)="onEditingItemsChange($event)"
+        (itemQuantityChange)="onPurchaseItemQuantityChange($event)"
+      />
+    </div>
   </div>
-</div>
+}

src/app/features/store/pages/checkout-page/checkout-page.component.scss

@@ -36,10 +36,33 @@
   }
 
   &__cart-col {
-
     max-height: 80vh;
     overflow: hidden;
     display: flex;
     flex-direction: column;
   }
 }
+
+.checkout-page__loading {
+  display: grid;
+  min-height: 420px;
+  place-items: center;
+  align-content: center;
+  gap: 1rem;
+  color: #666666;
+}
+
+.checkout-page__spinner {
+  width: 3rem;
+  height: 3rem;
+  border: 0.25rem solid rgba(32, 32, 32, 0.08);
+  border-top-color: var(--tenant-primary);
+  border-radius: 50%;
+  animation: checkout-page-spin 0.8s linear infinite;
+}
+
+@keyframes checkout-page-spin {
+  to {
+    transform: rotate(360deg);
+  }
+}

src/app/features/store/pages/checkout-page/checkout-page.component.spec.ts

@@ -234,6 +234,9 @@ describe('CheckoutPageComponent payment validation', () => {
     const purchase = {
       id: 25,
       cart_id: null,
+      status: 'created',
+      payment_method: null,
+      transfer_payer_dni: null,
       nombre_apellido: 'Datos de la compra',
       email: 'compra@example.com',
       dni: '11111111',
@@ -293,6 +296,99 @@ describe('CheckoutPageComponent payment validation', () => {
     });
   });
 
+  it('keeps the checkout hidden while the purchase is loading', async () => {
+    let resolvePurchase!: (purchase: any) => void;
+    routeQueryParamMap = convertToParamMap({ purchase: 25 });
+    checkoutServiceStub.getPurchase.mockReturnValue(
+      new Promise((resolve) => {
+        resolvePurchase = resolve;
+      }),
+    );
+    const { component } = createComponent();
+
+    expect(component.isLoadingPurchase()).toBe(true);
+
+    resolvePurchase({
+      id: 25,
+      status: 'created',
+      payment_method: null,
+      transfer_payer_dni: null,
+      items: [],
+      subtotal: '0.00',
+      total: '0.00',
+    });
+    await Promise.resolve();
+
+    expect(component.isLoadingPurchase()).toBe(false);
+    expect(component.checkoutStepIndex()).toBe(0);
+  });
+
+  it('opens a pending purchase on the payment step and restores its payment method', async () => {
+    routeQueryParamMap = convertToParamMap({ purchase: 25 });
+    checkoutServiceStub.getPurchase.mockResolvedValue({
+      id: 25,
+      status: 'pending_payment',
+      payment_method: 'transfer',
+      transfer_payer_dni: '12345678',
+      items: [],
+      subtotal: '100.00',
+      total: '100.00',
+    });
+    const { component } = createComponent();
+    await Promise.resolve();
+
+    expect(component.checkoutStepIndex()).toBe(1);
+    expect(component.selectedPaymentMethod()).toBe('transfer');
+    expect(component.transferDni()).toBe('12345678');
+    expect(component.isLoadingPurchase()).toBe(false);
+  });
+
+  it('generates a new QR when reopening a pending QR purchase', async () => {
+    routeQueryParamMap = convertToParamMap({ purchase: 25 });
+    checkoutServiceStub.getPurchase.mockResolvedValue({
+      id: 25,
+      status: 'pending_payment',
+      payment_method: 'qr',
+      transfer_payer_dni: null,
+      items: [],
+      subtotal: '100.00',
+      total: '100.00',
+    });
+    const { component } = createComponent();
+    await Promise.resolve();
+    await Promise.resolve();
+
+    expect(component.checkoutStepIndex()).toBe(1);
+    expect(component.selectedPaymentMethod()).toBe('qr');
+    expect(checkoutServiceStub.generatePaymentIntent).toHaveBeenCalledWith(
+      'tenant-test',
+      25,
+      'qr',
+    );
+    expect(component.qrData()).toBe('qr-value');
+    expect(component.qrPaymentStatus()).toBe('waiting');
+  });
+
+  it.each(['paid', 'cancelled', 'rejected', 'expired'])(
+    'redirects a %s purchase to its status page',
+    async (status) => {
+      routeQueryParamMap = convertToParamMap({ purchase: 25 });
+      checkoutServiceStub.getPurchase.mockResolvedValue({
+        id: 25,
+        status,
+        payment_method: null,
+        transfer_payer_dni: null,
+        items: [],
+        subtotal: '100.00',
+        total: '100.00',
+      });
+      createComponent();
+      await Promise.resolve();
+
+      expect(routerStub.navigate).toHaveBeenCalledWith(['/checkout/status', 25]);
+    },
+  );
+
   it('updates a purchase item while editing and refreshes checkout totals', async () => {
     const updatedPurchase = {
       id: 25,
@@ -318,12 +414,7 @@ describe('CheckoutPageComponent payment validation', () => {
       quantity: 3,
     });
 
-    expect(checkoutServiceStub.updateItemQuantity).toHaveBeenCalledWith(
+    expect(checkoutServiceStub.updateItemQuantity).toHaveBeenCalledWith('tenant-test', 25, 91, 3);
-      'tenant-test',
-      25,
-      91,
-      3,
-    );
     expect(component.createdPurchase()).toBe(updatedPurchase);
     expect(component.isUpdatingItem()).toBe(false);
   });

src/app/features/store/pages/checkout-page/checkout-page.component.ts

@@ -77,6 +77,8 @@ export class CheckoutPageComponent implements OnInit, OnDestroy {
   });
 
   protected readonly createdPurchase = signal<PurchaseDetailResponse | null>(null);
+  protected readonly isLoadingPurchase = signal(true);
+  protected readonly checkoutStepIndex = signal(0);
 
   protected readonly cartSubtotal = computed(() => {
     const purchase = this.createdPurchase();
@@ -198,10 +200,7 @@ export class CheckoutPageComponent implements OnInit, OnDestroy {
 
     this.isPreparingItemEdit.set(true);
     try {
-      const purchase = await this.checkoutService.prepareItemEditing(
+      const purchase = await this.checkoutService.prepareItemEditing(tenant.codigo, purchaseId);
-        tenant.codigo,
-        purchaseId,
-      );
       this.createdPurchase.set(purchase);
     } catch (error) {
       console.error('Failed to prepare purchase item editing:', error);
@@ -574,8 +573,39 @@ export class CheckoutPageComponent implements OnInit, OnDestroy {
 
     try {
       const purchase = await this.checkoutService.getPurchase(tenant.codigo, purchaseId);
+
+      if (
+        purchase.status === 'paid' ||
+        purchase.status === 'cancelled' ||
+        purchase.status === 'rejected' ||
+        purchase.status === 'expired'
+      ) {
+        this.navigateToPurchaseStatus(purchaseId);
+        return;
+      }
+
+      if (purchase.status !== 'created' && purchase.status !== 'pending_payment') {
+        void this.router.navigate(['/']);
+        return;
+      }
+
       this.createdPurchaseId.set(purchase.id);
       this.createdPurchase.set(purchase);
+      this.checkoutStepIndex.set(purchase.status === 'pending_payment' ? 1 : 0);
+
+      if (
+        purchase.status === 'pending_payment' &&
+        this.paymentMethods.some((method) => method.id === purchase.payment_method)
+      ) {
+        this.selectedPaymentMethod.set(purchase.payment_method as PaymentMethod);
+        this.transferDni.set(purchase.transfer_payer_dni ?? '');
+      }
+
+      this.isLoadingPurchase.set(false);
+
+      if (purchase.status === 'pending_payment' && purchase.payment_method === 'qr') {
+        await this.selectPaymentMethod('qr');
+      }
     } catch (error) {
       console.error('Failed to load purchase:', error);
       void this.router.navigate(['/']);

src/app/shared/components/stepper/stepper.component.spec.ts

@@ -14,7 +14,7 @@ import { StepComponent } from './step.component';
         <div id="content-2">Content 2</div>
       </app-step>
     </app-stepper>
-  `
+  `,
 })
 class TestHostComponent {
   @ViewChild('stepper') stepper!: StepperComponent;
@@ -25,7 +25,7 @@ class TestHostComponent {
 describe('StepperComponent & StepComponent', () => {
   async function setup() {
     await TestBed.configureTestingModule({
-      imports: [TestHostComponent, StepperComponent, StepComponent]
+      imports: [TestHostComponent, StepperComponent, StepComponent],
     }).compileComponents();
 
     const fixture = TestBed.createComponent(TestHostComponent);
@@ -50,6 +50,18 @@ describe('StepperComponent & StepComponent', () => {
     expect(content2).toBeNull();
   });
 
+  it('can initialize on a specified step', async () => {
+    await TestBed.configureTestingModule({
+      imports: [StepperComponent, StepComponent],
+    }).compileComponents();
+
+    const fixture = TestBed.createComponent(StepperComponent);
+    fixture.componentRef.setInput('initialStepIndex', 1);
+    fixture.detectChanges();
+
+    expect(fixture.componentInstance.currentStepIndex()).toBe(1);
+  });
+
   it('advances to step 2 when next() is called and current step is valid', async () => {
     const { fixture, component } = await setup();
 

src/app/shared/components/stepper/stepper.component.ts

@@ -1,4 +1,10 @@
-import { ChangeDetectionStrategy, Component, contentChildren, signal } from '@angular/core';
+import {
+  ChangeDetectionStrategy,
+  Component,
+  contentChildren,
+  input,
+  linkedSignal,
+} from '@angular/core';
 import { StepComponent } from './step.component';
 import { NgClass } from '@angular/common';
 
@@ -11,7 +17,8 @@ import { NgClass } from '@angular/common';
 })
 export class StepperComponent {
   readonly steps = contentChildren(StepComponent);
-  readonly currentStepIndex = signal(0);
+  readonly initialStepIndex = input(0);
+  readonly currentStepIndex = linkedSignal(() => this.initialStepIndex());
 
   next() {
     const currentSteps = this.steps();