# Auth Domain

Handles user authentication (login and registration) against the configured server endpoint. Provides the login, register, and user-bar UI components.

## Module map

```
auth/
├── application/
│   └── auth.service.ts              HTTP login/register against the active server endpoint
│
├── feature/
│   ├── login/                       Login form component
│   ├── register/                    Registration form component
│   └── user-bar/                    Displays current user or login/register links
│
└── index.ts                         Barrel exports
```

## Service overview

`AuthService` resolves the API base URL from `ServerDirectoryFacade`, then makes POST requests for login and registration. It does not hold session state itself; after a successful login the calling component stores `currentUserId` in localStorage and dispatches `UsersActions.setCurrentUser` into the NgRx store.

```mermaid
graph TD
    Login[LoginComponent]
    Register[RegisterComponent]
    UserBar[UserBarComponent]
    Auth[AuthService]
    SD[ServerDirectoryFacade]
    Store[NgRx Store]

    Login --> Auth
    Register --> Auth
    UserBar --> Store
    Auth --> SD
    Login --> Store

    click Auth "application/auth.service.ts" "HTTP login/register"
    click Login "feature/login/" "Login form"
    click Register "feature/register/" "Registration form"
    click UserBar "feature/user-bar/" "Current user display"
    click SD "../server-directory/application/server-directory.facade.ts" "Resolves API URL"
```

## Login flow

```mermaid
sequenceDiagram
    participant User
    participant Login as LoginComponent
    participant Auth as AuthService
    participant SD as ServerDirectoryFacade
    participant API as Server API
    participant Store as NgRx Store

    User->>Login: Submit credentials
    Login->>Auth: login(username, password)
    Auth->>SD: getApiBaseUrl()
    SD-->>Auth: https://server/api
    Auth->>API: POST /api/auth/login
    API-->>Auth: { userId, displayName }
    Auth-->>Login: success
    Login->>Store: UsersActions.setCurrentUser
    Login->>Login: localStorage.setItem(currentUserId)
```

## Registration flow

Registration follows the same pattern but posts to `/api/auth/register` with an additional `displayName` field. On success the user is treated as logged in and the same store dispatch happens.

## User bar

`UserBarComponent` reads the current user from the NgRx store. When logged in it shows the user's display name; when not logged in it shows links to the login and register views.