# CLAUDE.md

This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.

## Project Overview

FocusBuddy is a Flutter-based focus timer app designed for neurodivergent minds, implementing a "no-punishment" philosophy. The core concept is that distractions during focus sessions are tracked but don't interrupt the timer, providing a gentler approach to productivity tracking.

## Commands

### Development Setup
```bash
# Check Flutter version and environment
flutter doctor

# Get dependencies
flutter pub get

# Generate localization files (required after editing .arb files)
flutter gen-l10n

# Generate Hive adapters (required after modifying model classes)
flutter pub run build_runner build

# Clean build artifacts
flutter clean
```

### Running the App
```bash
# List available devices/emulators
flutter devices

# Run on default device
flutter run

# Run on specific device
flutter run -d <device_id>

# Run on Chrome (web)
flutter run -d chrome

# Run with hot reload (default in debug mode)
flutter run --hot
```

### Building
```bash
# Build APK for Android
flutter build apk

# Build App Bundle for Google Play
flutter build appbundle

# Build for iOS (requires macOS)
flutter build ios

# Build for Windows
flutter build windows
```

### Testing & Analysis
```bash
# Run static analysis
flutter analyze

# Run tests
flutter test

# Check for outdated packages
flutter pub outdated
```

## Architecture

### Core Philosophy
The app follows a **no-punishment approach** to focus tracking:
- Timer continues running even when user reports a distraction
- Distractions are tracked via "I got distracted" button
- Encouragement messages replace negative feedback
- All distraction counts are for awareness, not judgment

### Key Technical Decisions

**State Management**: Simple `StatefulWidget` approach (no external state management)
- Focus session state managed locally in `FocusScreen`
- Settings and preferences stored in `shared_preferences`
- Historical data stored in Hive local database

**Data Persistence**:
- **Hive** for focus session history (typeId 0 for `FocusSession`)
- **SharedPreferences** for app settings (onboarding status, default duration, locale)
- Sessions stored with full distraction tracking but continue regardless of interruptions

**Notifications**:
- Background notifications when app is inactive during focus session
- Uses `flutter_local_notifications` with `WidgetsBindingObserver` lifecycle tracking
- Notification updates every 30 seconds when app is backgrounded

**Internationalization (i18n)**:
- Uses Flutter's official `intl` package with ARB files
- 13 supported languages (en, zh, ja, ko, es, de, fr, pt, ru, hi, id, it, ar)
- Locale can be changed at runtime without app restart via `MyApp.updateLocale()`
- Localization files generated in `lib/l10n/` via `flutter gen-l10n`

### Project Structure

```
lib/
├── main.dart                  # Entry point, app initialization
├── models/                    # Data models
│   ├── focus_session.dart     # Hive model for session data
│   ├── focus_session.g.dart   # Generated Hive adapter
│   └── distraction_type.dart  # Enum for distraction categories
├── screens/                   # UI screens
│   ├── onboarding_screen.dart # First-time user guide
│   ├── home_screen.dart       # Main screen with "Start Focus" button
│   ├── focus_screen.dart      # Active timer + distraction button
│   ├── complete_screen.dart   # Post-session summary
│   ├── history_screen.dart    # Past sessions list
│   └── settings_screen.dart   # Duration & locale settings
├── services/                  # Business logic
│   ├── storage_service.dart   # Hive database operations
│   ├── encouragement_service.dart # Random message picker
│   └── notification_service.dart  # Background notifications
├── theme/                     # Design system
│   ├── app_theme.dart         # Material theme config
│   ├── app_colors.dart        # Color palette constants
│   └── app_text_styles.dart   # Typography definitions
└── l10n/                      # Generated localization files
    ├── app_localizations.dart
    └── app_localizations_*.dart
```

### Data Flow

**Focus Session Lifecycle**:
1. User selects duration in `HomeScreen` (loads from SharedPreferences)
2. `FocusScreen` starts countdown timer with `Timer.periodic`
3. User can tap "I got distracted" → adds to `_distractions` list, timer continues
4. Timer completion or manual stop → `FocusSession` saved to Hive via `StorageService`
5. `CompleteScreen` shows stats fetched from `StorageService.getTodaySessions()`
6. `HistoryScreen` displays all sessions from `StorageService.getAllSessions()`

**Critical Implementation**: The distraction button **never** pauses the timer - this is the app's core differentiator.

### FocusSession Model

```dart
@HiveType(typeId: 0)
class FocusSession {
  DateTime startTime;
  int durationMinutes;      // Planned (e.g., 25)
  int actualMinutes;        // May be less if stopped early
  int distractionCount;     // Total distractions logged
  bool completed;           // True if timer reached zero
  List<String> distractionTypes; // Categories selected
}
```

### Theme System

Uses Google Fonts (Nunito) with centralized design tokens:
- **Primary Color**: `#6C63FF` (Purple)
- **Background**: `#F5F7FA` (Light Gray)
- **Text Primary**: `#2D3748` (Dark Gray)
- **Success**: `#48BB78` (Green - used sparingly)

All UI components reference `AppTextStyles` and `AppColors` constants - never use hardcoded values.

## MVP Feature Set

**Current Implementation** (as of git commit `005ad8d`):
- ✅ Onboarding flow with "no-punishment" philosophy explanation
- ✅ Configurable session duration (15/25/45 minutes)
- ✅ Background notifications during active sessions
- ✅ Distraction tracking with 4 categories
- ✅ Today's stats on completion screen
- ✅ History view (today's sessions only in MVP)
- ✅ Multi-language support (13 languages)
- ✅ Settings for duration and locale

**Intentionally Deferred** (see [README.md](README.md)):
- ⏸️ Variable duration slider (fixed presets preferred for MVP)
- ⏸️ White noise audio playback
- ⏸️ Weekly trend charts
- ⏸️ PDF report export
- ⏸️ AdMob integration (monetization post-validation)

## Working with Localization

### Adding/Editing Translations
1. Translations are defined in `l10n/app_en.arb` (source locale) and other `app_*.arb` files
2. After editing ARB files, regenerate code:
   ```bash
   flutter gen-l10n
   ```
3. Use in code:
   ```dart
   final l10n = AppLocalizations.of(context)!;
   Text(l10n.appTitle);
   ```

### Adding a New Language
1. Create `l10n/app_<locale>.arb` (copy from `app_en.arb`)
2. Add locale to `supportedLocales` in [main.dart](lib/main.dart:97-111)
3. Add to language picker in [settings_screen.dart](lib/screens/settings_screen.dart)
4. Run `flutter gen-l10n`

## Modifying Data Models

When changing Hive models (e.g., `FocusSession`):
1. Update model class with `@HiveField` annotations
2. Regenerate adapters:
   ```bash
   flutter pub run build_runner build --delete-conflicting-outputs
   ```
3. Consider migration strategy if changing existing fields (current MVP has no migration logic)

## Code Generation

This project uses code generation for:
- **Hive adapters**: `*.g.dart` files for model serialization
- **Localization**: `lib/l10n/app_localizations*.dart` from ARB files

Never edit generated files manually - always modify source files and regenerate.

## Platform-Specific Notes

### Android
- Minimum SDK: 21 (Android 5.0)
- Target SDK: 34 (Android 14)
- Notification permission auto-requested on Android 13+ via `permission_handler`

### iOS
- Requires Xcode for building
- Notification permissions requested via `DarwinInitializationSettings`
- See [MACOS_BUILD_GUIDE.md](MACOS_BUILD_GUIDE.md) for macOS-specific instructions

### Web
- Notifications explicitly disabled on web platform (see `NotificationService._initialized`)
- Uses responsive layout but primarily designed for mobile

## Design System Guidelines

When adding new UI components:
1. Use `AppColors` constants - never hardcode colors
2. Use `AppTextStyles` for typography - never inline text styles
3. Border radius should be 16px for cards/buttons (consistency)
4. Button minimum height: 56px (touch-friendly)
5. Padding: Use multiples of 8 (8, 16, 24, 32, 48, 60)
6. Never use red/destructive colors for distractions (core philosophy)

## Testing Strategy

Current implementation focuses on manual testing:
- Test timer countdown accuracy across different durations
- Verify background notifications appear when app is minimized
- Test distraction button during active session (ensure timer continues)
- Verify data persists after app restart (Hive)
- Test locale switching without app restart

## Known Constraints

1. **No backend server** - All data stored locally (intentional for privacy)
2. **No analytics** - No Firebase/Amplitude in MVP (intentional)
3. **Single-device only** - No cross-device sync
4. **Today-focused** - History screen shows minimal data in MVP

## Important Implementation Rules

1. **Never pause timer on distraction** - This would violate the core philosophy
2. **Never show negative/punitive messaging** - Use encouragement instead
3. **Always use localized strings** - No hardcoded English text
4. **Always save sessions to Hive** - Even if stopped early (actualMinutes < durationMinutes)
5. **Background notifications required** - Users need countdown visibility when multitasking

## Related Documentation

- [README.md](README.md) - Product optimization strategy and MVP scope
- [ui-design-spec.md](ui-design-spec.md) - Complete UI/UX specifications
- [mvp-launch-checklist.md](mvp-launch-checklist.md) - 4-week development roadmap
- [product-design.md](product-design.md) - Original product vision
- [MACOS_BUILD_GUIDE.md](MACOS_BUILD_GUIDE.md) - macOS/iOS build instructions