# AGENTS.md

This file contains optimizations and best practices for working with this TabataFit Expo project.

---

## 🚀 Command Optimizations

Use the following `rtk` commands for optimal performance:

| Command | rtk Equivalent | Speedup | Tokens Before | Tokens After | Savings |
|---------|----------------|---------|---------------|--------------|---------|
| `ls` / `tree` | `rtk ls` | 10x | 2,000 | 400 | -80% |
| `cat` / `read` | `rtk read` | 20x | 40,000 | 12,000 | -70% |
| `grep` / `rg` | `rtk grep` | 8x | 16,000 | 3,200 | -80% |
| `git status` | `rtk git status` | 10x | 3,000 | 600 | -80% |
| `git diff` | `rtk git diff` | 5x | 10,000 | 2,500 | -75% |
| `git log` | `rtk git log` | 5x | 2,500 | 500 | -80% |
| `git add/commit/push` | `rtk git` | 8x | 1,600 | 120 | -92% |
| `cargo test` / `npm test` | `rtk test` | 5x | 25,000 | 2,500 | -90% |
| `ruff check` | `rtk lint` | 3x | 3,000 | 600 | -80% |
| `pytest` | `rtk pytest` | 4x | 8,000 | 800 | -90% |
| `go test` | `rtk gotest` | 3x | 6,000 | 600 | -90% |
| `docker ps` | `rtk docker` | - | - | - | - |

### Usage Examples

```bash
# Instead of: ls -la src/
rtk ls src/

# Instead of: cat package.json
rtk read package.json

# Instead of: grep -r "useEffect" src/
rtk grep "useEffect" src/

# Instead of: git status
rtk git status

# Instead of: npm test
rtk test

# Instead of: ruff check .
rtk lint
```

---

## 📱 Expo Best Practices

### Development Workflow

**CRITICAL: Always try Expo Go first before creating custom builds.**

1. **Start with Expo Go**: Run `npx expo start` and scan the QR code with Expo Go
2. **Check if features work**: Test your app thoroughly in Expo Go
3. **Only create custom builds when required**

#### When Custom Builds Are Required

Use `npx expo run:ios/android` or `eas build` ONLY when using:
- **Local Expo modules** (custom native code in `modules/`)
- **Apple targets** (widgets, app clips, extensions via `@bacons/apple-targets`)
- **Third-party native modules** not included in Expo Go
- **Custom native configuration** that can't be expressed in `app.json`

#### When Expo Go Works

Expo Go supports a huge range of features out of the box:
- All `expo-*` packages (camera, location, notifications, etc.)
- Expo Router navigation
- Most UI libraries (reanimated, gesture handler, etc.)
- Push notifications, deep links, and more

### Common Commands

```bash
# Development
npx expo start              # Start development server
npx expo start --tunnel     # If network issues
npx expo start --clear      # Clear cache
npx tsc --noEmit            # Type check
npx expo install <pkg>      # Install Expo-compatible packages

# Building
npx eas-cli@latest build --profile development     # Dev build
npx eas-cli@latest build -p ios --profile production --submit  # Build and submit iOS
npx testflight              # Quick TestFlight shortcut

# Development Client (when native code changes)
npx expo start --dev-client
```

### Code Style Rules

#### File Naming
- Use kebab-case for file names (e.g., `workout-card.tsx`)
- Never use special characters in file names
- Always remove old route files when moving or restructuring navigation

#### Imports
- Use path aliases from `tsconfig.json` instead of relative imports
- Prefer aliases over relative imports for refactors
- Always use import statements at the top of the file

#### Library Preferences
- ✅ `expo-audio` not `expo-av`
- ✅ `expo-video` not `expo-av`
- ✅ `expo-image` with `source="sf:name"` for SF Symbols
- ✅ `react-native-safe-area-context` not react-native SafeAreaView
- ✅ `process.env.EXPO_OS` not `Platform.OS`
- ✅ `React.use` not `React.useContext`
- ❌ Never use modules removed from React Native: Picker, WebView, SafeAreaView, AsyncStorage
- ❌ Never use legacy expo-permissions
- ❌ Never use intrinsic elements like 'img' or 'div' unless in webview

### Route Structure

```
app/
  _layout.tsx          # Root layout with tabs
  (tabs)/              # Group routes for tabs
    _layout.tsx        # Tabs layout
    index.tsx          # Home tab
    workouts.tsx       # Workouts tab
    activity.tsx       # Activity tab
    browse.tsx         # Browse tab
    profile.tsx        # Profile tab
  player/
    [id].tsx           # Workout player
```

#### Route Rules
- Routes belong in the `app` directory
- Never co-locate components, types, or utilities in the app directory
- Ensure the app always has a route that matches "/"
- Always use `_layout.tsx` files to define stacks

### UI Guidelines

#### Responsiveness
- Always wrap root component in a scroll view for responsiveness
- Use `<ScrollView contentInsetAdjustmentBehavior="automatic" />` instead of `<SafeAreaView>`
- `contentInsetAdjustmentBehavior="automatic"` should be applied to FlatList and SectionList
- Use flexbox instead of Dimensions API
- ALWAYS prefer `useWindowDimensions` over `Dimensions.get()`

#### Styling
- Prefer flex gap over margin and padding styles
- Prefer padding over margin where possible
- Inline styles not StyleSheet.create unless reusing styles is faster
- Use `{ borderCurve: 'continuous' }` for rounded corners
- ALWAYS use a navigation stack title instead of a custom text element
- When padding a ScrollView, use `contentContainerStyle` padding
- Add entering and exiting animations for state changes

#### Shadows
Use CSS `boxShadow` style prop. NEVER use legacy React Native shadow or elevation styles.

```tsx
<View style={{ boxShadow: "0 1px 2px rgba(0, 0, 0, 0.05)" }} />
```

#### Text Styling
- Add the `selectable` prop to every `<Text/>` element displaying important data
- Counters should use `{ fontVariant: 'tabular-nums' }` for alignment

#### Safe Area
- Always account for safe area with stack headers, tabs, or ScrollView/FlatList `contentInsetAdjustmentBehavior="automatic"`
- Ensure both top and bottom safe area insets are accounted for

### Navigation Patterns

#### Stack Configuration

```tsx
import { Stack } from 'expo-router/stack';

<Stack
  screenOptions={{
    headerTransparent: true,
    headerShadowVisible: false,
    headerLargeTitleShadowVisible: false,
    headerLargeStyle: { backgroundColor: "transparent" },
    headerTitleStyle: { color: PlatformColor("label") },
    headerLargeTitle: true,
    headerBlurEffect: "none",
    headerBackButtonDisplayMode: "minimal",
  }}
>
  <Stack.Screen name="index" options={{ title: "Home" }} />
</Stack>
```

#### Links with Previews

```tsx
import { Link } from 'expo-router';

<Link href="/settings">
  <Link.Trigger>
    <Pressable>
      <Card />
    </Pressable>
  </Link.Trigger>
  <Link.Preview />
  <Link.Menu>
    <Link.MenuAction title="Share" icon="square.and.arrow.up" />
    <Link.MenuAction title="Delete" icon="trash" destructive />
  </Link.Menu>
</Link>
```

#### Modal/Sheet Presentations

```tsx
// Modal
<Stack.Screen name="modal" options={{ presentation: "modal" }} />

// Form Sheet
<Stack.Screen
  name="sheet"
  options={{
    presentation: "formSheet",
    sheetGrabberVisible: true,
    sheetAllowedDetents: [0.5, 1.0],
    contentStyle: { backgroundColor: "transparent" },
  }}
/>
```

### Data Fetching

#### Environment Variables
- Use `EXPO_PUBLIC_` prefix for client-side environment variables
- Never put secrets in `EXPO_PUBLIC_` variables (visible in built app)
- Restart the dev server after changing `.env` files

```bash
# .env
EXPO_PUBLIC_API_URL=https://api.example.com
EXPO_PUBLIC_SUPABASE_URL=your-supabase-url
```

#### API Client Pattern

```tsx
const BASE_URL = process.env.EXPO_PUBLIC_API_URL;

export const apiClient = {
  get: async <T,>(path: string): Promise<T> => {
    const response = await fetch(`${BASE_URL}${path}`);
    if (!response.ok) throw new Error(`HTTP ${response.status}`);
    return response.json();
  },
};
```

#### React Query Setup

```tsx
// app/_layout.tsx
import { QueryClient, QueryClientProvider } from "@tanstack/react-query";

const queryClient = new QueryClient({
  defaultOptions: {
    queries: {
      staleTime: 1000 * 60 * 5, // 5 minutes
      retry: 2,
    },
  },
});
```

### EAS Build Configuration

```json
{
  "cli": {
    "version": ">= 16.0.1",
    "appVersionSource": "remote"
  },
  "build": {
    "production": {
      "autoIncrement": true,
      "ios": {
        "resourceClass": "m-medium"
      }
    },
    "development": {
      "developmentClient": true,
      "distribution": "internal"
    }
  },
  "submit": {
    "production": {}
  }
}
```

### Testing & Type Checking

```bash
# TypeScript
npx tsc --noEmit

# Run tests
npm test

# Lint
npx eslint .
```

### Key Takeaways

1. **Start simple**: Always test in Expo Go before creating custom builds
2. **Follow conventions**: Use Expo Router patterns, kebab-case filenames
3. **Use modern APIs**: Prefer `expo-audio`, `expo-video`, `expo-image`
4. **Handle safe areas**: Use `contentInsetAdjustmentBehavior="automatic"`
5. **Style with CSS**: Use `boxShadow` instead of legacy shadow props
6. **Type everything**: Use TypeScript strict mode, no `any`
7. **Secure tokens**: Use `expo-secure-store` for sensitive data
8. **Environment config**: Use `EXPO_PUBLIC_` prefix for client env vars

---

## 📝 Project Context

**TabataFit** — "Apple Fitness+ for Tabata"

- **Framework**: Expo SDK 52 (managed)
- **Navigation**: Expo Router v3
- **State**: Zustand + AsyncStorage
- **Video**: expo-av → HLS streaming
- **Audio**: expo-av (coaching + music)
- **Animations**: React Native Animated
- **Payments**: RevenueCat
- **Analytics**: PostHog

### Design System

```typescript
BACKGROUND: '#000000'    // Pure black
SURFACE: '#1C1C1E'       // Charcoal
BRAND: '#FF6B35'         // Flame orange
REST: '#5AC8FA'          // Ice blue
SUCCESS: '#30D158'       // Energy green
```

### Phase Colors (Critical)

```typescript
PREP: '#FF9500'    // Orange-yellow
WORK: '#FF6B35'    // Flame orange
REST: '#5AC8FA'    // Ice blue
COMPLETE: '#30D158' // Green
```

---

*Last updated: March 14, 2026*