# ISA-Frontend Architecture: Quick Reference Guide

## Project Overview at a Glance

| Aspect | Details |
|--------|---------|
| **Project Type** | Angular 20.3.6 Monorepo (Domain-Driven Design) |
| **Build Tool** | Nx 21.3.2 |
| **Total Libraries** | 63 (organized by domain + infrastructure) |
| **Main Application** | `isa-app` (only runnable app) |
| **Domains** | OMS, Remission, Checkout, Catalogue, Availability, CRM |
| **UI Components** | 17 specialized design system libraries |
| **Testing** | Jest (legacy) + Vitest (modern) - migration in progress |
| **State Management** | NgRx Signals with entity normalization |
| **API Clients** | 10 auto-generated from Swagger/OpenAPI specs |
| **Styling** | Tailwind CSS + 7 custom plugins |
| **Authentication** | OAuth2/OIDC via `angular-oauth2-oidc` |
| **Barcode Support** | Scandit Web Datacapture |
| **Analytics** | Matomo integration |

---

## Domain Summary

### 1. Order Management System (OMS) - 9 Libraries
**Focus:** Return workflows and receipt management

| Library | Purpose |
|---------|---------|
| `oms-data-access` | State + API integration |
| `oms-feature-return-search` | Receipt search interface |
| `oms-feature-return-details` | Item selection & configuration |
| `oms-feature-return-process` | Dynamic return questions |
| `oms-feature-return-summary` | Confirmation & printing |
| `oms-feature-return-review` | Completion review |
| `oms-shared-product-info` | Product display |
| `oms-shared-task-list` | Task management UI |
| `oms-utils-translation` | Receipt type labels |

**Key APIs:** oms-api, isa-api, print-api

---

### 2. Remission (Returns Management) - 8 Libraries
**Focus:** Warehouse return processing (mandatory + department)

| Library | Purpose |
|---------|---------|
| `remission-data-access` | State + API integration |
| `remission-feature-remission-list` | Main list view |
| `remission-feature-remission-return-receipt-list` | Receipt list |
| `remission-feature-remission-return-receipt-details` | Receipt details |
| `remission-shared-product` | Product components |
| `remission-shared-remission-start-dialog` | Start workflow |
| `remission-shared-return-receipt-actions` | Action buttons |
| `remission-shared-search-item-to-remit-dialog` | Item search |

**Key APIs:** Remission-specific via ISA backend

---

### 3. Checkout & Rewards - 6 Libraries
**Focus:** Shopping cart, orders, loyalty rewards

| Library | Purpose |
|---------|---------|
| `checkout-data-access` | Cart state + API |
| `checkout-feature-reward-catalog` | Reward browsing |
| `checkout-feature-reward-shopping-cart` | Cart with rewards |
| `checkout-feature-reward-order-confirmation` | Order confirmation |
| `checkout-shared-product-info` | Product display |
| `checkout-shared-reward-selection-dialog` | Reward selection |

**Key APIs:** checkout-api, crm-api (bonus cards)

---

### 4. Catalogue - 1 Library
**Focus:** Product search and discovery

| Library | Purpose |
|---------|---------|
| `catalogue-data-access` | Search + filtering |

**Key APIs:** cat-search-api, availability-api

---

### 5. Availability - 1 Library
**Focus:** Product stock checking

| Library | Purpose |
|---------|---------|
| `availability-data-access` | Stock queries |

**Key APIs:** availability-api

---

### 6. CRM - 1 Library
**Focus:** Customer data and bonus cards

| Library | Purpose |
|---------|---------|
| `crm-data-access` | Customer + bonus card state |

**Key APIs:** crm-api

---

## Architecture Layers

```
┌─────────────────────────────────┐
│  FEATURE LAYER (User-Facing)    │
│  - Components with routes       │
│  - User interactions            │
│  - Navigation handlers          │
└──────────────┬──────────────────┘
               │ imports
┌──────────────▼──────────────────┐
│  SHARED LAYER (Reusable)        │
│  - UI components (17 libs)      │
│  - Shared components (7 libs)   │
│  - Domain shared                │
└──────────────┬──────────────────┘
               │ imports
┌──────────────▼──────────────────┐
│  DATA ACCESS LAYER (State)      │
│  - NgRx Signal Stores           │
│  - API Services                 │
│  - Entity management            │
└──────────────┬──────────────────┘
               │ imports
┌──────────────▼──────────────────┐
│  INFRASTRUCTURE (Foundation)    │
│  - Core libraries (5)           │
│  - Common utilities (3)         │
│  - Generated APIs (10)          │
│  - Utilities (3)                │
└─────────────────────────────────┘
```

---

## State Management Pattern

### NgRx Signals Store Structure

```typescript
export const orderStore = signalStore(
  // 1. State definition
  withState({
    orders: [] as Order[],
    selected: null as Order | null,
    loading: false,
    error: null as Error | null,
  }),
  
  // 2. Entity management (auto-normalization)
  withEntities({ entity: type<Order>() }),
  
  // 3. Computed values
  withComputed((store) => ({
    orderCount: computed(() => store.orders().length),
    hasSelected: computed(() => store.selected() !== null),
  })),
  
  // 4. Methods for state mutations
  withMethods((store, api = inject(OmsApiService)) => ({
    load: rxMethod<void>(
      pipe(
        tapResponse(
          (orders) => patchState(store, setAllEntities(orders)),
          (error) => handleError(error)
        )
      )
    ),
    select: (order: Order) => {
      patchState(store, { selected: order });
    },
  })),
  
  // 5. Auto persistence
  withStorage({ key: 'orders' }),
  
  // 6. Cleanup hooks
  withHooks({
    onInit: ({ load }) => load(),
    onDestroy: () => console.log('Store destroyed'),
  })
);
```

**Key Features:**
- Signals: Reactive properties
- Entity management: Auto-normalized state
- Methods: Encapsulated mutations
- Storage: Automatic persistence
- Hooks: Lifecycle management

---

## Component Structure

### Standalone Component Example

```typescript
@Component({
  selector: 'oms-return-search',
  standalone: true,
  imports: [
    CommonModule,
    ReactiveFormsModule,
    // Shared components
    UiSearchBar,
    UiButton,
    OmsProductInfo,
    UiEmptyState,
  ],
  template: `
    <div class="container">
      <ui-search-bar (search)="onSearch($event)" />
      
      @if (store.receipts(); as receipts) {
        @if (receipts.length > 0) {
          <oms-product-info 
            *ngFor="let receipt of receipts"
            [receipt]="receipt"
          />
        } @else {
          <ui-empty-state title="Keine Belege" />
        }
      } @loading {
        <ui-skeleton-loader />
      }
    </div>
  `,
  styles: [`...`],
})
export class OmsReturnSearchComponent {
  protected store = inject(omsStore);
  private api = inject(OmsApiService);

  onSearch(term: string) {
    this.store.searchReceipts(term);
  }
}
```

**Best Practices:**
- ✅ Standalone components only
- ✅ Explicit imports
- ✅ Inject store, not services
- ✅ Use store methods directly
- ✅ Let control flow (@if, @for)

---

## Common Patterns

### 1. Search with Debouncing

```typescript
export class SearchComponent {
  private searchTerm$ = new Subject<string>();
  
  results$ = this.searchTerm$.pipe(
    debounceTime(300),
    distinctUntilChanged(),
    switchMap((term) => this.api.search(term)),
    takeUntilKeydown('Escape')
  );

  onSearch(term: string) {
    this.searchTerm$.next(term);
  }
}
```

### 2. Modal/Dialog Handling

```typescript
export class DialogComponent {
  private dialog = inject(DialogService);
  
  openRewardSelection() {
    this.dialog.open(RewardSelectionDialog, {
      data: { cart: this.cart },
    }).afterClosed$.subscribe((reward) => {
      if (reward) {
        this.store.selectReward(reward);
      }
    });
  }
}
```

### 3. Form Validation

```typescript
export class ReturnProcessComponent {
  form = new FormGroup({
    reason: new FormControl('', [Validators.required]),
    quantity: new FormControl(1, [Validators.min(1)]),
    comments: new FormControl(''),
  });

  submit() {
    if (this.form.valid) {
      this.store.submitReturn(this.form.value);
    }
  }
}
```

### 4. Responsive Design

```typescript
export class ResponsiveComponent {
  // Use breakpoint service instead of CSS-only
  isDesktop = breakpoint([
    Breakpoint.Desktop,
    Breakpoint.DesktopL,
    Breakpoint.DesktopXL,
  ]);

  template = `
    @if (isDesktop()) {
      <desktop-layout />
    } @else {
      <mobile-layout />
    }
  `;
}
```

---

## Common Commands

### Development
```bash
npm start                          # Start with SSL
npm test                           # Test all libraries
npm run build                      # Dev build
npm run build-prod                 # Production build
```

### Testing
```bash
npx nx test oms-data-access --skip-nx-cache
npx nx affected:test --skip-nx-cache
npm run ci                         # CI with coverage
```

### Code Quality
```bash
npm run lint                       # ESLint
npm run prettier                   # Format code
npm run docs:generate              # Update library ref
```

### API & Swagger
```bash
npm run generate:swagger           # Regenerate all APIs
npm run fix:files:swagger          # Unicode cleanup
```

### Dependency Analysis
```bash
npx nx graph                       # Visual dependency graph
npx nx show project oms-data-access --web false
npx nx affected:lint --skip-nx-cache
```

---

## File Organization by Domain

### OMS Domain Structure
```
libs/oms/
├── data-access/
│   └── src/
│       ├── index.ts
│       ├── stores/
│       │   ├── receipt.store.ts
│       │   └── return.store.ts
│       └── services/
│           ├── oms-api.service.ts
│           └── print.service.ts
├── feature/
│   ├── return-search/
│   ├── return-details/
│   ├── return-process/
│   ├── return-summary/
│   └── return-review/
├── shared/
│   ├── product-info/
│   └── task-list/
└── utils/
    └── translation/
```

### UI Component Structure
```
libs/ui/buttons/
├── src/
│   ├── index.ts
│   ├── primary-button.component.ts
│   ├── secondary-button.component.ts
│   ├── ...
│   └── buttons.module.ts
├── README.md
├── project.json
└── ...
```

---

## TypeScript Path Aliases

```json
{
  "paths": {
    // Domain data-access
    "@isa/oms/data-access": ["libs/oms/data-access/src/index.ts"],
    "@isa/remission/data-access": ["libs/remission/data-access/src/index.ts"],
    
    // UI components
    "@isa/ui/buttons": ["libs/ui/buttons/src/index.ts"],
    "@isa/ui/dialog": ["libs/ui/dialog/src/index.ts"],
    
    // Core infrastructure
    "@isa/core/logging": ["libs/core/logging/src/index.ts"],
    "@isa/core/storage": ["libs/core/storage/src/index.ts"],
    
    // Generated APIs
    "@generated/swagger/oms-api": ["generated/swagger/oms-api/src/index.ts"]
  }
}
```

---

## Styling & Design System

### Tailwind Utilities (ISA-Specific)

```html
<!-- Brand Colors -->
<div class="text-isa-accent-primary">Primary text</div>
<button class="bg-isa-accent-primary">Primary button</button>

<!-- Typography -->
<h1 class="isa-text-heading-1-bold">Large heading</h1>
<p class="isa-text-body-2-regular">Body text</p>

<!-- Custom Breakpoints -->
<div class="hidden isa-desktop:block">Desktop only</div>
<div class="block isa-desktop:hidden">Mobile only</div>

<!-- Custom Plugins -->
<button class="isa-button-primary">ISA Button</button>
<div class="isa-input-group">...</div>
```

### Custom Tailwind Plugins
1. button - Button styling
2. typography - Text utilities
3. menu - Menu styling
4. label - Label & tag styling
5. input - Input styling
6. section - Section containers
7. select-bullet - Select styling

---

## Testing Approach

### New Libraries (Vitest + Angular Testing Utils)
```typescript
import { TestBed, ComponentFixture } from '@angular/core/testing';
import { OmsReturnSearchComponent } from './oms-return-search.component';

describe('OmsReturnSearchComponent', () => {
  let component: OmsReturnSearchComponent;
  let fixture: ComponentFixture<OmsReturnSearchComponent>;

  beforeEach(async () => {
    await TestBed.configureTestingModule({
      imports: [OmsReturnSearchComponent],
    }).compileComponents();

    fixture = TestBed.createComponent(OmsReturnSearchComponent);
    component = fixture.componentInstance;
    fixture.detectChanges();
  });

  it('should create', () => {
    expect(component).toBeTruthy();
  });
});
```

### E2E Attributes
All templates must include data attributes:
```html
<button 
  data-what="submit-return"
  data-which="primary-action"
  [attr.data-order-id]="orderId"
>
  Submit Return
</button>
```

---

## Troubleshooting

| Issue | Solution |
|-------|----------|
| **Build cache stale** | `npx nx reset` or `--skip-nx-cache` |
| **Test failures** | Always use `--skip-nx-cache` |
| **Import not found** | Check `tsconfig.base.json` path alias |
| **Circular dependency** | Run `npx nx lint` to identify |
| **SSL certificate error** | Accept localhost certificate in browser |
| **State not persisting** | Check `withStorage()` in store |
| **API 401 Unauthorized** | Verify OAuth2 token in auth service |

---

## Quick Links

- **Library Reference:** `/docs/library-reference.md`
- **Architecture Analysis:** `/docs/architecture-analysis.md`
- **Dependency Hierarchy:** `/docs/dependency-hierarchy.md`
- **Testing Guidelines:** `/docs/guidelines/testing.md`
- **Nx Documentation:** https://nx.dev/
- **Angular Documentation:** https://angular.io/
- **NgRx Signals:** https://ngrx.io/guide/signals

---

## Getting Help

1. Check library README: `libs/[domain]/[layer]/[feature]/README.md`
2. Review existing examples in similar domains
3. Check `npx nx show project [project-name]`
4. Read CLAUDE.md for project-specific conventions
5. Review git history: `git log --oneline libs/[domain]`

---

## Performance Budgets

- **Main bundle:** 2MB warning, 5MB error (gzipped)
- **Initial load:** < 2s on 4G
- **Core (after auth):** < 5s

**Bundle Analysis:**
```bash
npx nx build isa-app --configuration=production --stats-json
webpack-bundle-analyzer dist/isa-app/browser/stats.json
```

---

## Monorepo Statistics

| Metric | Count |
|--------|-------|
| Total Libraries | 63 |
| Feature Components | 20 |
| UI Components | 17 |
| Data Access | 6 |
| Core Infrastructure | 5 |
| Shared Components | 7 |
| Utilities | 3 |
| Generated APIs | 10 |
| Lines of Code | ~500K+ |
| TypeScript Files | ~1,500 |
| Test Files | ~400 |
| Generated Test Coverage | Vitest: 34%, Jest: 65% |