# Frontend Architecture

## Tech Stack

| Package | Version | Purpose |
|---|---|---|
| React | 19.2 | UI framework |
| TypeScript | 6.0 | Type safety |
| Vite | 8.0 | Build tool and dev server |
| TanStack React Query | 5.99 | Server state management, caching, mutations |
| Zustand | 5.0 | Client state (auth, UI) |
| Axios | 1.15 | HTTP client with interceptors |
| React Router | 7.14 | Client-side routing |
| React Hook Form | 7.72 | Form state management |
| Zod | 4.3 | Schema validation |
| Tailwind CSS | 3.4 | Utility-first CSS framework |
| Lucide React | 1.8 | Icon library |
| clsx | 2.1 | Conditional class merging |

### Dev Dependencies

| Package | Purpose |
|---|---|
| Vitest 4.1 + jsdom | Unit testing |
| @testing-library/react 16 | Component testing |
| @testing-library/jest-dom 6 | DOM matchers |
| @testing-library/user-event 14 | User interaction simulation |
| Playwright 1.59 | E2E testing |
| ESLint 9 | Linting |
| TypeScript ESLint 8 | TypeScript lint rules |

## Project Structure

```
frontend/src/
├── main.tsx                          # Entry point, renders <App />
├── App.tsx                           # Router, QueryClientProvider, auth guard
├── index.css                         # Tailwind directives, neumorphic classes
├── vite-env.d.ts                     # Vite env type declarations
│
├── lib/
│   └── api.ts                        # Axios client, auth interceptors
│
├── store/
│   ├── auth.store.ts                 # Auth state (token, user, isAuthenticated)
│   └── ui.store.ts                   # UI state (sidebar, notifications)
│
├── hooks/
│   ├── useServers.ts                 # TanStack Query hooks for server CRUD + lifecycle
│   ├── useServerDetail.ts            # TanStack Query hooks for config, players, bans, missions, mods, RCon
│   ├── useAuth.ts                    # Auth management hooks (users, password, logout)
│   ├── useGames.ts                   # Game type hooks (list, detail, schema, defaults)
│   └── useWebSocket.ts              # WebSocket connection with backoff + onEvent callback
│
├── pages/
│   ├── LoginPage.tsx                  # Login form with Zod validation
│   ├── DashboardPage.tsx              # Server grid with lifecycle controls
│   ├── ServerDetailPage.tsx           # Server detail with 7 tabs (overview, config, players, bans, missions, mods, logs)
│   ├── CreateServerPage.tsx           # 4-step server creation wizard (admin only)
│   └── SettingsPage.tsx               # Account (password change) + Users (admin user management)
│
├── components/
│   ├── layout/
│   │   └── Sidebar.tsx               # Left nav with server list
│   ├── servers/
│   │   ├── ServerCard.tsx            # Server card with actions
│   │   ├── ServerHeader.tsx          # Server name, status, stats grid, lifecycle buttons
│   │   ├── ConfigEditor.tsx          # Tabbed config section editor; per-field widgets via useServerConfigSchema
│   │   ├── PlayerTable.tsx           # Current players + history with search
│   │   ├── BanTable.tsx              # Ban list + create/revoke form
│   │   ├── MissionList.tsx           # Available missions + Mission Rotation sections; multi-file upload
│   │   ├── ModList.tsx               # Split-pane mod selector (Available vs Selected); Apply Selection button
│   │   └── LogViewer.tsx             # Log display with level filter + collapsible Log Files browser (download/delete)
│   ├── settings/
│   │   ├── PasswordChange.tsx         # Password change form
│   │   └── UserManager.tsx            # User CRUD table (admin only)
│   └── ui/
│       ├── StatusLed.tsx             # Colored status indicator dot
│       └── TagListEditor.tsx         # Dynamic string-list editor (add/remove items)
│
└── __tests__/
    ├── api.test.ts                    # Axios interceptor tests
    ├── auth.store.test.ts            # Auth store tests
    ├── ui.store.test.ts              # UI store tests
    ├── logger.test.ts                # Logger level-filtering tests
    ├── StatusLed.test.tsx            # StatusLed component tests
    ├── LoginPage.test.tsx            # Login page tests
    ├── DashboardPage.test.tsx        # Dashboard page tests
    ├── ServerCard.test.tsx           # Server card rendering tests
    ├── ServerCard.handlers.test.tsx # Server card interaction tests
    ├── Sidebar.test.tsx              # Sidebar tests
    ├── useWebSocket.test.tsx         # WebSocket hook tests
    ├── useServers.test.tsx           # Server hooks tests (useServers, useServer, lifecycle, useUpdateServer, useKillServer)
    ├── useServerDetail.test.tsx      # Server detail hooks (config, players, bans, missions, mods, RCon, logfiles)
    ├── useAuth.test.tsx              # Auth hooks tests
    ├── useGames.test.tsx             # Games hooks tests
    └── CreateServerPage.test.tsx     # Create server wizard (steps, validation, submit, edge cases)
```

## Routes

| Path | Component | Auth | Status |
|---|---|---|---|
| `/login` | `LoginPage` | Public | Implemented |
| `/` | `DashboardPage` | Protected | Implemented |
| `/servers/:serverId` | `ServerDetailPage` | Protected | Implemented (7 tabs) |
| `/servers/new` | `CreateServerPage` | Protected (admin only) | Implemented (4-step wizard) |
| `/settings` | `SettingsPage` | Protected | Implemented (Account + Users tabs) |

`ProtectedLayout` wraps all non-login routes. When `isAuthenticated` is false, it redirects to `/login`.

## Component Tree

```
App
├── QueryClientProvider
│   ├── BrowserRouter
│   │   ├── /login → LoginPage
│   │   └── /* → ProtectedLayout
│   │       ├── Sidebar
│   │       │   ├── Languard branding
│   │       │   ├── Dashboard link
│   │       │   ├── Server list (from useServers)
│   │       │   └── Settings link
│   │       └── main content area
│   │           ├── / → DashboardPage
│   │           │   ├── "2 servers configured" heading
│   │           │   ├── Add Server button
│   │           │   └── Server grid
│   │           │       └── ServerCard × N
│   │           │           ├── StatusLed + name + game type
│   │           │           ├── Stats: Players, Port, Restarts
│   │           │           └── Action buttons: Start/Stop/Restart
│   │           ├── /servers/:id → ServerDetailPage
│   │           │   ├── ServerHeader (status, stats, lifecycle buttons)
│   │           │   ├── Tab bar (Overview, Config, Players, Bans, Missions, Mods, Logs)
│   │           │   ├── OverviewTab (stats grid, executable path)
│   │           │   ├── ConfigEditor (section tabs, per-field widgets from schema, optimistic locking)
│   │           │   ├── PlayerTable (current + history with search)
│   │           │   ├── BanTable (ban list + create/revoke)
│   │           │   ├── MissionList (Available + Rotation sections, multi-file upload)
│   │           │   ├── ModList (split-pane: Available | Selected; Apply Selection)
│   │           │   └── LogViewer (level filter, real-time stream + Log Files browser)
│   │           ├── /servers/new → CreateServerPage
│   │           │   └── 4-step wizard (Game Type → Info → Options → Review)
│   │           └── /settings → SettingsPage
│   │               ├── Account tab → PasswordChange
│   │               └── Users tab → UserManager (admin only)
│   └── ReactQueryDevtools
```

## State Management

### Server State (TanStack Query)

All server data flows through TanStack Query hooks:

**Server CRUD** (`useServers.ts`):

| Hook | Type | Endpoint | Cache Key |
|---|---|---|---|
| `useServers()` | Query | `GET /api/servers` | `["servers"]` (refetch every 30s) |
| `useServer(id)` | Query | `GET /api/servers/:id` | `["servers", id]` |
| `useStartServer()` | Mutation | `POST /api/servers/:id/start` | Invalidates `["servers", id]`, `["servers"]` |
| `useStopServer()` | Mutation | `POST /api/servers/:id/stop` | Invalidates both caches |
| `useRestartServer()` | Mutation | `POST /api/servers/:id/restart` | Invalidates `["servers", id]` |
| `useCreateServer()` | Mutation | `POST /api/servers` | Invalidates `["servers"]` |
| `useDeleteServer()` | Mutation | `DELETE /api/servers/:id` | Invalidates `["servers"]` |
| `useUpdateServer(id)` | Mutation | `PUT /api/servers/:id` | Invalidates `["servers", id]`, `["servers"]` |
| `useKillServer()` | Mutation | `POST /api/servers/:id/kill` | Invalidates `["servers", id]`, `["servers"]` |

**Server Detail** (`useServerDetail.ts`):

| Hook | Type | Endpoint | Cache Key |
|---|---|---|---|
| `useServerConfig(id)` | Query | `GET /api/servers/:id/config` | `["servers", id, "config"]` |
| `useServerConfigSection(id, section)` | Query | `GET /api/servers/:id/config/:section` | `["servers", id, "config", section]` |
| `useServerConfigSchema(id)` | Query | `GET /api/servers/:id/config/schema` (per-field widget hints for ~80 fields: text, toggle, select, number, password, tag-list, hidden, textarea) | `["servers", id, "config", "schema"]` |
| `useServerConfigPreview(id)` | Query | `GET /api/servers/:id/config/preview` | `["servers", id, "config", "preview"]` |
| `useServerPlayers(id)` | Query | `GET /api/servers/:id/players` | `["players", id]` |
| `useServerPlayerHistory(id, opts?)` | Query | `GET /api/servers/:id/players/history` | `["players", id, "history", opts]` |
| `useServerBans(id)` | Query | `GET /api/servers/:id/bans` | `["bans", id]` |
| `useServerMissions(id)` | Query | `GET /api/servers/:id/missions` | `["missions", id]` |
| `useServerMissionRotation(id)` | Query | `GET /api/servers/:id/missions/rotation` | `["missions", id, "rotation"]` |
| `useServerMods(id)` | Query | `GET /api/servers/:id/mods` | `["mods", id]` |
| `useUpdateConfigSection(id, section)` | Mutation | `PUT /api/servers/:id/config/:section` | Invalidates config keys |
| `useCreateBan(id)` | Mutation | `POST /api/servers/:id/bans` | Invalidates `["bans", id]` |
| `useRevokeBan(id)` | Mutation | `DELETE /api/servers/:id/bans/:banId` | Invalidates `["bans", id]` |
| `useUploadMission(id)` | Mutation | `POST /api/servers/:id/missions` (multipart, `File[]`) | Invalidates `["missions", id]` |
| `useUpdateMissionRotation(id)` | Mutation | `PUT /api/servers/:id/missions/rotation` | Invalidates rotation + server config |
| `useDeleteMission(id)` | Mutation | `DELETE /api/servers/:id/missions/:filename` | Invalidates `["missions", id]` |
| `useSetEnabledMods(id)` | Mutation | `PUT /api/servers/:id/mods/enabled` body: `EnabledModEntry[]` | Invalidates `["mods", id]` |
| `useSendCommand(id)` | Mutation | `POST /api/servers/:id/rcon/command` | No invalidation |
| `useKickPlayer(id)` | Mutation | `POST /api/servers/:id/players/:slot_id/kick` | Invalidates `["players", id]` |
| `useBanPlayer(id)` | Mutation | `POST /api/servers/:id/players/:slot_id/ban` | Invalidates players + bans |
| `useServerLogFiles(id)` | Query | `GET /api/servers/:id/logfiles` | `["servers", id, "logfiles"]` (refetch 30s) |
| `useDeleteLogFile(id)` | Mutation | `DELETE /api/servers/:id/logfiles/:filename` | Invalidates logfiles |

**Auth** (`useAuth.ts`):

| Hook | Type | Endpoint |
|---|---|---|
| `useCurrentUser()` | Query | `GET /api/auth/me` |
| `useUsers()` | Query | `GET /api/auth/users` |
| `useChangePassword()` | Mutation | `PUT /api/auth/password` |
| `useCreateUser()` | Mutation | `POST /api/auth/users` |
| `useDeleteUser()` | Mutation | `DELETE /api/auth/users/:id` |
| `useLogout()` | Mutation | `POST /api/auth/logout` + clear auth state |

**Games** (`useGames.ts`):

| Hook | Type | Endpoint |
|---|---|---|
| `useGamesList()` | Query | `GET /api/games` |
| `useGameDetail(gameType)` | Query | `GET /api/games/:gameType` |
| `useGameConfigSchema(gameType)` | Query | `GET /api/games/:gameType/config-schema` |
| `useGameDefaults(gameType)` | Query | `GET /api/games/:gameType/defaults` |

**Key type notes**:
- `Server` type in `useServers.ts` uses `game_port`, `current_players`, `max_players` (matches enriched API response)
- `Mission` type: `{ name, filename, size_bytes, terrain }` — terrain parsed from filename
- `Mod` type: `{ name, path, size_bytes, enabled, is_server_mod, display_name, workshop_id }` — `display_name`/`workshop_id` from mod.cpp/meta.cpp; `is_server_mod` controls `-serverMod=` vs `-mod=`
- `EnabledModEntry` type: `{ name: string, is_server_mod: boolean }` — used as `useSetEnabledMods` mutation input
- `Ban` type: `{ id, server_id, guid, name, reason, banned_by, banned_at, expires_at, is_active, game_data }` (matches API)
- There is no REST endpoint for logs — logs are only pushed via WebSocket events

QueryClient defaults: `staleTime: 10s`, `retry: 2`, `refetchOnWindowFocus: false`.

### Client State (Zustand)

**auth.store.ts** — Persisted to localStorage under `languard-auth`:
- `token: string | null` — JWT access token
- `user: { id, username, role } | null` — Current user
- `isAuthenticated: boolean` — Derived on rehydration
- `setAuth(token, user)` — Sets token, user, and writes `languard_token` to localStorage
- `clearAuth()` — Clears all state and localStorage keys

**ui.store.ts** — In-memory only:
- `sidebarOpen: boolean` — Sidebar collapse state
- `activeServerId: number | null` — Highlighted server in sidebar
- `notifications: Notification[]` — Toast notifications (auto-remove after 5s)
- `addNotification(type, message)` — Add toast with auto-dismiss
- `removeNotification(id)` — Manual dismiss

## API Client

`src/lib/api.ts` configures Axios with:

- **Base URL**: `VITE_API_URL` env var, defaults to `http://localhost:8000`
- **Timeout**: 30 seconds
- **Request interceptor**: Reads `languard_token` from localStorage, adds `Authorization: Bearer <token>` header
- **Response interceptor**: On 401, checks if URL starts with `/api/auth/` — if NOT an auth endpoint, clears token and redirects to `/login`. Auth endpoint 401s are left for the calling component to handle.

Standard response envelope: `{ success: boolean, data: T | null, error?: string }`

## WebSocket

`useWebSocket.ts` connects to `VITE_WS_URL` (default `ws://localhost:8000`):
- Accepts `UseWebSocketOptions` (or `number[]` for backward compat): `{ serverIds?, onEvent? }`
- Passes JWT token as query parameter: `/ws?token=...&server_id=...`
- Exponential backoff reconnect: starts 2s, doubles up to 30s max
- Close code 4001 = explicit disconnect (no reconnect)
- `onEvent` callback: receives raw WebSocket events for custom handling (e.g., log accumulation in ServerDetailPage)
- Event handlers invalidate TanStack Query caches:
  - `server_status` → `["servers", id]` + `["servers"]`
  - `metrics` → `["metrics", id]`
  - `log` → no cache key (no REST endpoint for logs; use onEvent callback instead)
  - `players` → `["players", id]`

**Important**: There is no REST endpoint for server logs. Logs are only available via WebSocket push events. Components that need log data must use the `onEvent` callback to accumulate log entries in local state, then pass them to `LogViewer` as props.

## Design System

Dark neumorphic theme defined in `tailwind.config.js`:

**Colors:**
- Surface: base `#1a1a2e`, raised `#1e1e35`, recessed `#16162a`, overlay `#22223a`
- Accent: amber `#f59e0b` with bright/dim/glow variants
- Status: running green, stopped gray, crashed red, starting amber, restarting blue
- Text: primary `#e2e8f0`, secondary `#94a3b8`, muted `#475569`

**Neumorphic classes:** `neu-card`, `neu-input`, `btn-primary`, `btn-danger`, `btn-ghost`, `status-led-*`

**Custom shadows:** `neu-raised`, `neu-raised-lg`, `neu-recessed`, plus glow variants

**Fonts:** Inter (sans), JetBrains Mono (mono)

## Testing

### Unit Tests (167 tests, Vitest + React Testing Library)

| Test File | Tests | Coverage |
|---|---|---|
| `api.test.ts` | 4 | Interceptors: token header, 401 redirect (non-auth), 401 no-redirect (auth) |
| `auth.store.test.ts` | 8 | Init state, setAuth, clearAuth, localStorage sync, rehydration, partialize |
| `ui.store.test.ts` | 5 | Init state, toggleSidebar, setActiveServer, add/remove notifications |
| `logger.test.ts` | 10 | All 4 log methods, level filtering (debug/warn/error), message format |
| `StatusLed.test.tsx` | 8 | Status classes, showLabel, sizes |
| `LoginPage.test.tsx` | 4 | Form render, validation, API call, error display |
| `DashboardPage.test.tsx` | 5 | Loading/error/empty states, card rendering |
| `ServerCard.test.tsx` | 10 | Card rendering, button visibility, disabled states, actions |
| `ServerCard.handlers.test.tsx` | 9 | Start/stop/restart success/failure notifications |
| `Sidebar.test.tsx` | 6 | Branding, links, loading state, server list, active highlight |
| `useWebSocket.test.tsx` | 5 | No-connect without token, connect, token in URL, invalidation, cleanup |
| `useServers.test.tsx` | 12 | Server CRUD + lifecycle hooks, useUpdateServer, useKillServer |
| `useServerDetail.test.tsx` | 20+ | Config, players, bans, missions, mods, mutations, logfiles, cache invalidation |
| `useAuth.test.tsx` | 7 | Current user, users, change password, create/delete user, logout |
| `useGames.test.tsx` | 5 | Games list, detail, config schema, defaults |
| `CreateServerPage.test.tsx` | 14 | All 4 wizard steps, validation, submit, non-admin gate, API error handling |

### E2E Tests (38 tests, Playwright)

**Login Flow** (6 tests):
- Display login form, branding, validation errors
- Error on invalid credentials (mocked 401)
- Navigation to dashboard on successful login
- Loading state ("Signing in...")

**Dashboard** (12 tests):
- Header, server count, server cards, server names
- Add Server button, sidebar with server list
- Stop button for running server, Start button for stopped
- Player count display, server detail navigation
- Empty state, error state

**Server Detail — 5 UX phases** (15 tests, fully mocked):
- Overview: server name/status, all 6 tabs visible
- Config: field labels rendered (Hostname, BattlEye)
- Missions: mission names, terrain names, Upload button
- Mods: display names, enabled/disabled state
- Players: player list, ping values, Kick buttons
- Logs: collapsible Log Files section, Download buttons, live log viewer area

**Full Stack Integration** (5 tests):
- Login + see A3Master on dashboard (real backend)
- A3Master server details in card (real backend)
- Server detail navigation (real backend)
- Unauthenticated redirect to login
- API response shape validation

## Configuration

### Vite (`vite.config.ts`)
- Path alias `@` → `./src`
- Dev server on port 5173
- Proxy: `/api` → `http://localhost:8000`, `/ws` → `ws://localhost:8000`

### Vitest (`vitest.config.ts`)
- `jsdom` environment
- Global test APIs
- Setup: `src/__tests__/setup.ts` (imports jest-dom matchers)
- Excludes `tests-e2e` directory

### Playwright (`playwright.config.ts`)
- Chromium only
- `baseURL: http://localhost:5173`
- Traces on first retry, screenshots on failure, video on failure
- Dev server auto-started via `npm run dev`
- CI: retries=2, single worker, `forbidOnly`