# Contributing to Familienarchiv

For the full collaboration rules (issue workflow, PR process, Red/Green TDD, commit conventions) see [COLLABORATING.md](./COLLABORATING.md).
For coding style see [CODESTYLE.md](./CODESTYLE.md).
For the system architecture see [docs/ARCHITECTURE.md](./docs/ARCHITECTURE.md) (introduced in DOC-2; until that PR merges, see [docs/architecture/c4-diagrams.md](./docs/architecture/c4-diagrams.md)).
For domain terminology see [docs/GLOSSARY.md](./docs/GLOSSARY.md).

---

## 1. Environment setup

**Prerequisites:** Java 21 (SDKMAN), Node 24 (nvm), Docker

**Activate SDKMAN and nvm before running `java`, `mvn`, `node`, or `npm`:**

```bash
source "$HOME/.sdkman/bin/sdkman-init.sh"
export NVM_DIR="$HOME/.nvm" && [ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"
```

---

## 2. Daily development workflow

**Startup order — services must start in this sequence:**

```bash
# 1. Start PostgreSQL and MinIO
docker compose up -d db minio

# 2. Start the backend (separate terminal)
cd backend && ./mvnw spring-boot:run

# 3. Start the frontend (separate terminal)
cd frontend && npm install && npm run dev
```

> `npm install` also wires up the Husky pre-commit hook via the `prepare` script.
> Run it before your first commit, or the hook will fail to execute.

> **Do not use `docker-compose.ci.yml` locally** — it disables the bind mounts that the dev workflow depends on.

**Regenerate TypeScript types after any backend API change:**

```bash
# Backend must be running with dev profile
cd frontend && npm run generate:api
```

> ⚠️ Forgetting this step is the most common cause of "where did my TypeScript type go?" — always regenerate after changing models or endpoints.

**Test commands:**

```bash
cd backend && ./mvnw test                 # backend unit + slice tests
cd frontend && npm run test               # Vitest unit tests
cd frontend && npm run check              # svelte-check (type errors)
cd frontend && npx playwright test        # Playwright e2e tests
```

**Branch naming:** `<type>/<issue-number>-<short-description>`, e.g. `feat/398-contributing`

**Commits:** one logical change per commit; reference the Gitea issue:

```
feat(person): add aliases endpoint

Closes #42
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
```

### Test-type decision matrix

| What you're testing | Test type | Tool |
|---|---|---|
| Service business logic, calculations | Unit test | JUnit + `@ExtendWith(MockitoExtension.class)` |
| HTTP contract, request validation, error codes | Controller slice test | `@WebMvcTest` |
| Server `load` function | Vitest unit | Import directly, mock `fetch` |
| Shared UI component | Vitest browser-mode | `render()` + `getByRole()` |
| Full user-facing flow, navigation, forms | E2E | Playwright |

---

## 3. Walkthrough A — Add a new domain

**Example:** adding a `citation` domain (formal references to documents).

Both the backend and frontend are organised **domain-first**. A new domain means adding a package on both sides under the same name.

### Backend

1. Create `backend/src/main/java/org/raddatz/familienarchiv/citation/`

2. Add entity, repository, service, controller, and DTOs flat in the package:
   - **Entity** `Citation.java` — annotate with `@Entity @Data @Builder @NoArgsConstructor @AllArgsConstructor`; use `@GeneratedValue(strategy = GenerationType.UUID)` for the `id` field; add `@Schema(requiredMode = REQUIRED)` on every field the backend always populates
   - **Repository** `CitationRepository.java` — extends `JpaRepository<Citation, UUID>`
   - **Service** `CitationService.java` — `@Service @RequiredArgsConstructor`; write methods `@Transactional`, read methods unannotated; cross-domain data goes through the other domain's service, never its repository
   - **Controller** `CitationController.java` — `@RestController @RequestMapping("/api/citations")`

3. Add `@RequirePermission(Permission.WRITE_ALL)` on every `POST`, `PUT`, `PATCH`, and `DELETE` endpoint — **this is not optional**. Read-only `GET` endpoints stay unannotated.

4. Add a Flyway migration: `backend/src/main/resources/db/migration/V{n}__{description}.sql` (use the next sequential number after the highest existing one).

5. **Write failing tests before any implementation** (Red step):
   - Service unit test for business logic (`@ExtendWith(MockitoExtension.class)`)
   - `@WebMvcTest` slice test for each HTTP endpoint

6. Rebuild with `--spring.profiles.active=dev` and run `npm run generate:api` in `frontend/`.

### Frontend

7. Create `frontend/src/lib/citation/` — domain-specific Svelte components and TypeScript utilities go here.

8. Add routes under `frontend/src/routes/citations/` as needed.

9. Add a per-domain `README.md` in both the backend package folder and `frontend/src/lib/citation/` (per DOC-6).

### Documentation

10. Update `docs/ARCHITECTURE.md` Section 2 to include the new domain.
11. Update `docs/GLOSSARY.md` if new terms are introduced.
12. Update the ESLint boundary allow-list in `frontend/eslint.config.js` if the domain needs to import from another domain.

---

## 4. Walkthrough B — Add a new endpoint

**Example:** `POST /api/persons/{id}/aliases` — attach a name alias to an existing person.

### Red (write failing tests first)

1. Write a failing `@WebMvcTest` controller slice test:
   ```java
   @Test
   void addAlias_returns201_whenAliasCreated() { ... }
   ```

2. Write a failing service unit test:
   ```java
   @Test
   void addAlias_throwsNotFound_whenPersonDoesNotExist() { ... }
   ```

### Green (implement)

3. Add the service method in `PersonService.java`:
   ```java
   @Transactional
   public PersonNameAlias addAlias(UUID personId, PersonNameAliasDTO dto) { ... }
   ```

4. Add the controller method in `PersonController.java`:
   ```java
   @PostMapping("/{id}/aliases")
   @RequirePermission(Permission.WRITE_ALL)
   public ResponseEntity<PersonNameAlias> addAlias(@PathVariable UUID id,
                                                   @RequestBody PersonNameAliasDTO dto) { ... }
   ```
   `@RequirePermission(Permission.WRITE_ALL)` on every state-mutating endpoint — **not optional**.

5. Validate user-supplied inputs at the controller boundary:
   ```java
   if (dto.name() == null || dto.name().isBlank())
       throw new ResponseStatusException(HttpStatus.BAD_REQUEST, "name is required");
   ```
   Validate at system boundaries; trust internal service code.

6. Use `DomainException` for domain errors:
   ```java
   DomainException.notFound(ErrorCode.PERSON_NOT_FOUND, "Person not found: " + id)
   ```
   If you need a new error code, add it to `ErrorCode.java`, mirror it in
   `frontend/src/lib/shared/errors.ts`, and add translation keys in `messages/{de,en,es}.json`.

7. Mark every field the backend always populates with `@Schema(requiredMode = REQUIRED)` — this drives TypeScript type generation.

### Types and tests

8. Rebuild with `--spring.profiles.active=dev`, then `npm run generate:api` in `frontend/`.

   > ⚠️ **Always regenerate types after any API change.** This is the #1 cause of "where did my TypeScript type go?"

9. Run the full test suite — all green before committing.

---

## 5. Walkthrough C — Add a new frontend page

**Example:** `/persons/[id]/timeline` — a chronological event timeline for one person.

### Red (write failing test first)

1. Write a failing Playwright E2E test for the user flow:
   ```typescript
   test('timeline shows events in chronological order', async ({ page }) => {
       await page.goto('/persons/1/timeline');
       // assertions...
   });
   ```

### Green (implement)

2. Create `frontend/src/routes/persons/[id]/timeline/+page.svelte`

3. Add `frontend/src/routes/persons/[id]/timeline/+page.server.ts` for the SSR load:
   ```typescript
   import { createApiClient } from '$lib/shared/api.server';
   export const load: PageServerLoad = async ({ params, fetch }) => {
       const api = createApiClient(fetch);
       const result = await api.GET('/api/persons/{id}', { params: { path: { id: params.id } } });
       if (!result.response.ok) throw error(result.response.status, '...');
       return { person: result.data! };
   };
   ```

4. Domain-specific components (e.g. `TimelineEntry.svelte`) → `frontend/src/lib/person/`

5. Shared primitives (e.g. a generic date-range display) → `frontend/src/lib/shared/primitives/`

6. UI patterns to follow:
   - Back navigation: `import BackButton from '$lib/shared/primitives/BackButton.svelte'`
   - Date display: always append `T12:00:00` — `new Intl.DateTimeFormat('de-DE', …).format(new Date(val + 'T12:00:00'))` — prevents UTC off-by-one errors
   - Brand colors: `brand-navy`, `brand-mint`, `brand-sand` (defined in `src/routes/layout.css`)
   - Accessibility: touch targets ≥ 44 px (`min-h-[44px]`); focus rings (`focus-visible:ring-2 focus-visible:ring-brand-navy`); `aria-label` on icon-only buttons; `aria-live="polite"` on dynamic status messages

7. Add Paraglide i18n keys in `messages/de.json`, `messages/en.json`, `messages/es.json`.

8. If adding a new error code: mirror in `frontend/src/lib/shared/errors.ts` and add translation keys.

9. Make all tests green before committing.

---

## 6. Conventions reference

### Error handling

| Scenario | Pattern |
|---|---|
| Domain entity not found | `DomainException.notFound(ErrorCode.X, "…")` |
| Permission denied | `DomainException.forbidden("…")` |
| Concurrent edit conflict | `DomainException.conflict(ErrorCode.X, "…")` |
| Infrastructure failure | `DomainException.internal(ErrorCode.X, "…")` |
| Simple controller validation | `throw new ResponseStatusException(HttpStatus.BAD_REQUEST, "…")` |

New error code: `ErrorCode.java` → `frontend/src/lib/shared/errors.ts` → `messages/{de,en,es}.json`.

### DTOs

- Input DTOs live flat in the domain package (e.g. `PersonUpdateDTO.java`)
- Responses are the entity itself — no separate response DTOs
- `@Schema(requiredMode = REQUIRED)` on every field the backend always populates

### Frontend API client

```typescript
const api = createApiClient(fetch); // from $lib/shared/api.server
const result = await api.GET('/api/persons/{id}', { params: { path: { id } } });
if (!result.response.ok) {
    const code = (result.error as unknown as { code?: string })?.code;
    throw error(result.response.status, getErrorMessage(code));
}
return { person: result.data! }; // non-null assertion is safe after the ok check
```

For multipart/form-data (file uploads): bypass the typed client and use raw `fetch` — the client cannot handle it.

### Date handling

| Context | Pattern |
|---|---|
| Form display | German `dd.mm.yyyy` with auto-dot insertion via `handleDateInput()` |
| Wire format | ISO 8601 via a hidden `<input type="hidden" name="documentDate" value={dateIso}>` |
| Display | `new Intl.DateTimeFormat('de-DE', …).format(new Date(val + 'T12:00:00'))` |

### Security checklist (new endpoint)

- `@RequirePermission(Permission.WRITE_ALL)` on every `POST`, `PUT`, `PATCH`, `DELETE` — required, not optional
- Validate all user-supplied inputs at the controller boundary before passing to the service
- Parameterised queries only — never interpolate user input into JPQL/SQL strings
- No raw user input in log messages — use `{}` placeholders: `log.warn("Not found: {}", id)`
- Validate content-type and size on upload endpoints before reading the stream

### Accessibility baseline (new frontend page)

- Touch targets ≥ 44 px on all interactive elements (`min-h-[44px]`)
- Focus rings on all focusable elements (`focus-visible:ring-2 focus-visible:ring-brand-navy`)
- `aria-label` on every icon-only button
- `aria-live="polite"` on dynamic status messages
- Color is never the sole status indicator

Full WCAG 2.1 AA reference: [docs/STYLEGUIDE.md](./docs/STYLEGUIDE.md).

### Lint and format

```bash
# Frontend
cd frontend && npm run lint     # Prettier + ESLint check
cd frontend && npm run format   # Auto-fix formatting
cd frontend && npm run check    # svelte-check (type errors)

# Backend — no standalone lint tool; compilation and test runs catch style issues
cd backend && ./mvnw test       # compile + test
cd backend && ./mvnw clean package -DskipTests  # compile-only check
```