# Memos Frontend Documentation

## Authentication and Middleware System

### Frontend Authentication Architecture

The frontend authentication system uses a combination of:

1. **React Context** for state management
2. **Route-based guards** for access control
3. **Connect RPC interceptors** for API authentication
4. **Layout-based protection** for UI components

### Core Authentication Components

#### 1. Auth Context (`web/src/contexts/AuthContext.tsx`)

```typescript
// Manages global authentication state
const AuthContext = createContext<AuthContextType>({
  currentUser: undefined,
  userGeneralSetting: undefined,
  isInitialized: false,
  isLoading: true,
  initialize: async () => {},
  logout: () => {},
  refetchSettings: async () => {}
});

// Provides authentication state to entire app
function AuthProvider({ children }: { children: React.ReactNode }) {
  // Handles token initialization, user fetching, logout logic
}
```

#### 2. Route Protection System

**Public Routes** (no auth required):

- `/auth` - Authentication pages
- `/auth/signup` - User registration
- `/auth/callback` - OAuth callback
- `/explore` - Public explore page
- `/u/:username` - User profiles
- `/memos/:uid` - Individual memo details

**Private Routes** (auth required):

- `/` (root) - Main dashboard
- `/attachments` - File attachments
- `/inbox` - Notifications
- `/archived` - Archived memos
- `/setting` - User settings

#### 3. Layout-Based Authentication Guards

**RootLayout** (`web/src/layouts/RootLayout.tsx`):

```typescript
const RootLayout = () => {
  const currentUser = useCurrentUser();
  
  useEffect(() => {
    if (!currentUser) {
      redirectOnAuthFailure(); // Redirects to /auth
    }
  }, [currentUser]);
  
  // Renders navigation and main content
  return (
    <div className="w-full min-h-full flex flex-row">
      <Navigation />
      <main>
        <Outlet />
      </main>
    </div>
  );
};
```

**Route Configuration** (`web/src/router/index.tsx`):

```typescript
const router = createBrowserRouter([
  {
    path: "/",
    element: <App />, // Handles instance initialization
    children: [
      {
        path: "/auth", // Public routes
        children: [
          { path: "", element: <SignIn /> },
          { path: "signup", element: <SignUp /> },
          { path: "callback", element: <AuthCallback /> }
        ]
      },
      {
        path: "/", // Protected routes (wrapped in RootLayout)
        element: <RootLayout />, // Auth guard here
        children: [
          {
            element: <MainLayout />, // Main app layout
            children: [
              { path: "", element: <Home /> },
              { path: "explore", element: <Explore /> }
              // ... other protected routes
            ]
          }
        ]
      }
    ]
  }
]);
```

### API Authentication Interceptors

#### Connect RPC Interceptor (`web/src/connect.ts`):

```typescript
const authInterceptor: Interceptor = (next) => async (req) => {
  const isRetryAttempt = req.header.get(RETRY_HEADER) === RETRY_HEADER_VALUE;
  const token = await getRequestToken();
  setAuthorizationHeader(req, token);

  try {
    return await next(req);
  } catch (error) {
    // Handle 401 Unauthorized
    if (error.code === Code.Unauthenticated && !isRetryAttempt) {
      try {
        // Attempt token refresh
        const newToken = await refreshAndGetAccessToken();
        setAuthorizationHeader(req, newToken);
        req.header.set(RETRY_HEADER, RETRY_HEADER_VALUE);
        return await next(req);
      } catch (refreshError) {
        redirectOnAuthFailure(); // Redirect to login
        throw refreshError;
      }
    }
    throw error;
  }
};
```

#### Token Management

- **Storage**: Access tokens stored in memory (not localStorage)
- **Refresh**: Automatic token refresh on 401 errors
- **Expiration**: Proactive refresh on tab focus
- **Cleanup**: Tokens cleared on logout/auth failure

### Authentication Flow

#### 1. App Initialization (`web/src/main.tsx`)

```typescript
// Early theme/locale setup to prevent flash
applyThemeEarly();
applyLocaleEarly();

// Initialize auth and instance contexts
<AuthProvider>
  <InstanceProvider>
    <RouterProvider router={router} />
  </InstanceProvider>
</AuthProvider>
```

#### 2. Authentication Check (`web/src/utils/auth-redirect.ts`)

```typescript
export function redirectOnAuthFailure(): void {
  const currentPath = window.location.pathname;
  
  // Allow public routes
  if (isPublicRoute(currentPath)) return;
  
  // Redirect private routes to auth
  if (isPrivateRoute(currentPath)) {
    clearAccessToken();
    window.location.replace(ROUTES.AUTH);
  }
}
```

#### 3. User Session Management

- Token refresh on window focus
- Automatic logout on token expiration
- Context cleanup on logout
- Query cache invalidation

### Key Security Features

- **Token Storage**: In-memory only (security best practice)
- **Automatic Refresh**: Handles token rotation seamlessly
- **Route Guards**: Prevent unauthorized access to protected routes
- **Context Isolation**: Auth state managed centrally
- **Error Handling**: Graceful degradation on auth failures
- **Session Cleanup**: Complete state reset on logout

### Related Files

- `web/src/contexts/AuthContext.tsx` - Authentication state management
- `web/src/layouts/RootLayout.tsx` - Main authentication guard
- `web/src/utils/auth-redirect.ts` - Route protection logic
- `web/src/connect.ts` - API authentication interceptors
- `web/src/router/index.tsx` - Route configuration
- `web/src/main.tsx` - App initialization

## Theme System Implementation

### Vite Build Process for Themes

The CSS themes are processed and built by **Vite** during the build process:

1. **Vite Configuration** (`web/vite.config.mts`)
   - Uses `@tailwindcss/vite` plugin for CSS processing
   - Tailwind CSS v4 handles theme token compilation
   - Themes are bundled during `pnpm build` process

2. **CSS Processing Pipeline**
   - Base styles imported in `web/src/index.css`
   - Theme-specific CSS files located in `web/src/themes/`
   - Vite processes `@theme inline` directives at build time
   - Dynamic theme switching handled via JavaScript at runtime

### Theme Architecture

#### Core Theme Files

- `web/src/index.css` - Main CSS entry point
- `web/src/themes/default.css` - Base theme with Tailwind token mappings
- `web/src/themes/default-dark.css` - Dark theme variables
- `web/src/themes/paper.css` - Paper-style theme
- `web/src/utils/theme.ts` - Theme loading and management logic

#### How Themes Are Built

##### 1. Build Time Processing (Vite + Tailwind)

```css
/* In web/src/themes/default.css */
@theme inline {
  --color-background: var(--background);
  --color-foreground: var(--foreground);
  /* ... other CSS variables */
}
```

- Tailwind compiles these into static CSS classes
- Shared across all themes
- Optimized during Vite build process

##### 2. Runtime Theme Switching

- JavaScript dynamically injects theme CSS
- Uses `?raw` import to get CSS as string
- Injects `<style>` elements into document head
- Controlled by `web/src/utils/theme.ts`

### Theme Loading Mechanism

In `web/src/utils/theme.ts`:

```typescript
import defaultDarkThemeContent from "../themes/default-dark.css?raw";
import paperThemeContent from "../themes/paper.css?raw";

const THEME_CONTENT: Record<ResolvedTheme, string | null> = {
  default: null,           // Uses base CSS
  "default-dark": defaultDarkThemeContent,
  paper: paperThemeContent,
};

// Dynamically injects theme CSS
const injectThemeStyle = (theme: ResolvedTheme): void => {
  if (theme === "default") return; // Use base CSS
  
  const css = THEME_CONTENT[theme];
  if (css) {
    const style = document.createElement("style");
    style.id = "instance-theme";
    style.textContent = css;
    document.head.appendChild(style);
  }
};
```

### Available Themes

1. **System** (`system`) - Follows OS preference
2. **Light** (`default`) - Default light theme
3. **Dark** (`default-dark`) - Dark mode theme
4. **Paper** (`paper`) - Paper-style theme

### Theme Selection Components

- `web/src/components/ThemeSelect.tsx` - Theme dropdown selector
- `web/src/pages/UserSetting.tsx` - User profile theme settings
- `web/src/contexts/InstanceContext.tsx` - Instance-wide theme defaults

### Build Process Commands

```bash
# Development
pnpm dev

# Production build (processes themes)
pnpm build

# The build process:
# 1. Vite processes Tailwind CSS
# 2. Theme CSS files are bundled
# 3. Dynamic theme loading code is included
# 4. Output goes to dist/ directory
```

### Key Technical Details

- **CSS-in-JS Approach**: Themes are injected as `<style>` elements
- **Tree Shaking**: Unused theme CSS is removed during build
- **Hot Reloading**: Theme changes reflect instantly in development
- **Performance**: Theme switching is instant (no page reload)
- **Storage**: Theme preference stored in localStorage
- **Fallback**: Defaults to "system" theme if none selected

The theme system leverages Vite's build optimization while maintaining runtime flexibility for dynamic theme switching.

## Menu and Navigation System

### Navigation Component Architecture

The menu/navigation system is implemented through the `Navigation` component which serves as the main sidebar navigation.

### Core Navigation Component (`web/src/components/Navigation.tsx`)

```typescript
interface NavLinkItem {
  id: string;
  path: string;
  title: string;
  icon: React.ReactNode;
}

const Navigation = (props: { collapsed?: boolean; className?: string }) => {
  const currentUser = useCurrentUser();
  const { data: notifications = [] } = useNotifications();
  
  // Navigation items are defined as objects
  const homeNavLink: NavLinkItem = {
    id: "header-memos",
    path: Routes.ROOT,
    title: t("common.memos"),
    icon: <LibraryIcon className="w-6 h-auto shrink-0" />
  };
  
  // Conditional navigation based on authentication state
  const navLinks: NavLinkItem[] = currentUser
    ? [homeNavLink, exploreNavLink, attachmentsNavLink, inboxNavLink]
    : [exploreNavLink, signInNavLink];
}
```

### Menu Items Configuration

#### For Authenticated Users

1. **Home** (`/`) - Main memos dashboard
   - Icon: `LibraryIcon`
   - Shows user's memos

2. **Explore** (`/explore`) - Public memos exploration
   - Icon: `EarthIcon`
   - Browse public content

3. **Attachments** (`/attachments`) - File management
   - Icon: `PaperclipIcon`
   - Manage uploaded files

4. **Inbox** (`/inbox`) - Notifications
   - Icon: `BellIcon` with badge
   - Shows unread notification count

#### For Unauthenticated Users

1. **Explore** (`/explore`) - Public content browsing
2. **Sign In** (`/auth`) - Authentication page
   - Icon: `UserCircleIcon`

### Navigation Layout Structure

#### Desktop (>768px)

- Fixed sidebar on left (`w-16` when collapsed, wider when expanded)
- `RootLayout` renders `Navigation` component vertically
- Collapsed state shows icons only with tooltips
- Expanded state shows icons + text labels

#### Mobile (<768px)

- `NavigationDrawer` component in mobile header
- Slide-out drawer from left side
- Full-width navigation when opened

### Navigation Implementation

```typescript
// In RootLayout.tsx
{sm && (
  <div className="fixed top-0 left-0 h-full w-16">
    <Navigation className="py-4" collapsed={true} />
  </div>
)}

// In MobileHeader.tsx
<NavigationDrawer /> // For mobile devices
```

### Key Features

#### 1. Conditional Rendering

- Different menus for authenticated vs unauthenticated users
- Notification badges for unread messages
- Responsive design for mobile/desktop

#### 2. Active State Management

```typescript
<NavLink
  className={({ isActive }) =>
    cn(
      "px-2 py-2 rounded-2xl border flex flex-row",
      isActive
        ? "bg-sidebar-accent text-sidebar-accent-foreground"
        : "border-transparent hover:bg-sidebar-accent"
    )
  }
  to={navLink.path}
>
```

#### 3. Collapsed State

- Icons only with tooltip hints
- Space-efficient for narrow screens
- Smooth transitions

#### 4. User Menu Integration

- Bottom section shows `UserMenu` component
- Profile/avatar display
- Settings and logout options

### Related Components

- `web/src/components/Navigation.tsx` - Main navigation logic
- `web/src/components/NavigationDrawer.tsx` - Mobile drawer implementation
- `web/src/components/UserMenu.tsx` - User profile dropdown
- `web/src/layouts/RootLayout.tsx` - Desktop layout with sidebar
- `web/src/components/MobileHeader.tsx` - Mobile header with drawer

### Internationalization

- Menu titles translated via `useTranslate()` hook
- Supports multiple languages
- Dynamic text based on user locale

The navigation system provides a clean, responsive menu that adapts to user authentication state and screen size while maintaining consistent UX across devices.

## Layout System (Masonry vs List)

### View Context Architecture

The layout system is managed through the `ViewContext` which provides global state management for layout preferences and sorting options.

### Core View Context (`web/src/contexts/ViewContext.tsx`)

```typescript
export type LayoutMode = "LIST" | "MASONRY";

interface ViewContextValue {
  orderByTimeAsc: boolean;  // Sort order
  layout: LayoutMode;       // Current layout mode
  toggleSortOrder: () => void;
  setLayout: (layout: LayoutMode) => void;
}

// Persistent storage in localStorage
const LOCAL_STORAGE_KEY = "memos-view-setting";

// Default state
return { orderByTimeAsc: false, layout: "LIST" as LayoutMode };
```

### Layout Modes

#### 1. LIST Layout (`"LIST"`)

- **Description**: Traditional linear list view
- **Implementation**: Single column layout
- **Behavior**: Memos displayed vertically in chronological order
- **Use Case**: Reading-focused, sequential browsing

#### 2. MASONRY Layout (`"MASONRY"`)

- **Description**: Pinterest-style grid layout
- **Implementation**: Multi-column responsive grid
- **Behavior**: Memos distributed based on actual rendered heights
- **Use Case**: Visual browsing, efficient space utilization

### Masonry Layout Implementation

#### Core Components

1. **MasonryView** (`web/src/components/MasonryView/MasonryView.tsx`)
   - Main container component
   - Manages column distribution
   - Uses CSS Grid for layout

2. **MasonryColumn** (`web/src/components/MasonryView/MasonryColumn.tsx`)
   - Represents individual columns
   - Contains assigned memos
   - Handles prefix elements (like memo editor)

3. **MasonryItem** (`web/src/components/MasonryView/MasonryItem.tsx`)
   - Wraps individual memos
   - Measures actual rendered height
   - Uses ResizeObserver for dynamic updates

4. **useMasonryLayout** Hook (`web/src/components/MasonryView/useMasonryLayout.ts`)
   - Calculates optimal column count
   - Distributes memos to columns
   - Manages height measurements

#### Key Features

##### 1. Height-Based Distribution

```typescript
// Smart algorithm that assigns memos to shortest column
const shortestColumnIndex = columnHeights.reduce(
  (minIndex, currentHeight, currentIndex) => 
    (currentHeight < columnHeights[minIndex] ? currentIndex : minIndex),
  0
);
```

##### 2. Dynamic Column Count

```typescript
const calculateColumns = useCallback(() => {
  if (!containerRef.current || listMode) return 1;
  
  const containerWidth = containerRef.current.offsetWidth;
  const scale = containerWidth / MINIMUM_MEMO_VIEWPORT_WIDTH;
  return scale >= 1.2 ? Math.ceil(scale) : 1;
}, [containerRef, listMode]);
```

##### 3. ResizeObserver Integration

```typescript
useEffect(() => {
  const measureHeight = () => {
    if (itemRef.current) {
      const height = itemRef.current.offsetHeight;
      onHeightChange(memo.name, height);
    }
  };
  
  resizeObserverRef.current = new ResizeObserver(measureHeight);
  resizeObserverRef.current.observe(itemRef.current);
}, [memo.name, onHeightChange]);
```

##### 4. Responsive Behavior

- Automatically adjusts columns based on viewport width
- Minimum width threshold for multi-column layout
- Smooth transitions during resizing

### Layout Switching

#### User Interface

```typescript
// MemoDisplaySettingMenu component
<Select value={layout} onValueChange={(value) => setLayout(value as "LIST" | "MASONRY")}>
  <SelectItem value="LIST">{t("memo.list")}</SelectItem>
  <SelectItem value="MASONRY">{t("memo.masonry")}</SelectItem>
</Select>
```

#### State Management

```typescript
const { layout, setLayout } = useView();

// Toggle between layouts
setLayout("MASONRY"); // or "LIST"

// Persistence
localStorage.setItem("memos-view-setting", JSON.stringify({ layout, orderByTimeAsc }));
```

### Integration with Memo Display

#### PagedMemoList Component

```typescript
const PagedMemoList = (props: Props) => {
  const { layout } = useView(); // Get current layout preference
  
  return (
    <div className="flex flex-col justify-start items-start w-full max-w-full">
      {layout === "MASONRY" ? (
        <MasonryView
          memoList={sortedMemoList}
          renderer={props.renderer}
          prefixElement={<MemoEditor />}
        />
      ) : (
        // Traditional list view implementation
        <ListView memoList={sortedMemoList} />
      )}
    </div>
  );
};
```

### Performance Optimizations

1. **Debounced Redistribution**: Prevents excessive re-layout during rapid changes
2. **Memoized Calculations**: Optimized height calculations and distribution algorithms
3. **Efficient State Updates**: Only re-render when necessary
4. **ResizeObserver Cleanup**: Proper memory management

### Related Files

- `web/src/contexts/ViewContext.tsx` - Global layout state management
- `web/src/components/MasonryView/` - Masonry layout implementation
- `web/src/components/MemoDisplaySettingMenu.tsx` - Layout selection UI
- `web/src/components/PagedMemoList/PagedMemoList.tsx` - Memo list container
- `web/src/components/MasonryView/README.md` - Detailed technical documentation

### User Experience Benefits

- **Choice**: Users can choose preferred browsing style
- **Persistence**: Layout preference saved across sessions
- **Responsiveness**: Adapts to different screen sizes
- **Performance**: Optimized rendering for both modes
- **Consistency**: Same memo content, different presentation

The layout system provides flexible viewing options that cater to different user preferences and use cases while maintaining optimal performance and responsive design.