Swiff iOS Development Assistant

Purpose

Use this skill when working on the Swiff iOS project to ensure consistency with established patterns, architecture, and coding standards. The skill includes expertise in:

• SwiftUI declarative UI development
• SwiftData persistence and migrations
• MVVM architecture with service layer
• WidgetKit home screen widgets
• iOS notifications and background tasks
• Subscription and expense management features
• Group expense splitting and calculations
• Security best practices for financial apps
• Accessibility standards
• Performance optimization

When to Use This Skill

Invoke this skill when:

• Starting work on any Swiff iOS feature or bug fix
• Understanding the project architecture and structure
• Implementing new views, models, or services
• Working with subscriptions, transactions, or group expenses
• Adding widgets or notifications
• Performing code reviews
• Handling data migrations
• Implementing security or accessibility features
• Optimizing performance
• Writing tests

Project Context

Swiff iOS is a comprehensive subscription and expense management app built with:

• SwiftUI for modern declarative UI
• SwiftData for data persistence (iOS 17+)
• Combine for reactive programming
• WidgetKit for home screen widgets

Core Features

1. Subscription Management – Track recurring subscriptions with renewal reminders
2. Expense Tracking – Log and categorize transactions
3. Group Expenses – Split bills and track balances
4. Analytics – Spending trends and forecasting
5. Notifications – Renewal reminders and alerts
6. Widgets – Quick access home screen widgets

Architecture Pattern

The project follows MVVM + Services pattern:

• Models: DataModels (domain) + SwiftDataModels (persistence)
• ViewModels: Service layer (DataManager, PersistenceService, etc.)
• Views: SwiftUI views with reusable components

Key Guidelines

Code Style

• Use @MainActor for services that interact with UI
• Prefer @Published properties in services for reactive updates
• Follow Swift naming conventions (PascalCase for types, camelCase for variables)
• Use comprehensive error handling with typed errors

Architecture

• Keep business logic in Services layer, not in Views
• Use domain models (DataModels) for business logic
• Convert between domain and persistence models explicitly
• Inject DataManager via @EnvironmentObject

Testing

• Write unit tests for business logic and calculations
• Test error conditions and edge cases
• Mock services for isolated testing
• Use SwiftUI previews for UI testing

Security

• Sanitize all user inputs
• Use biometric authentication for sensitive operations
• Encrypt sensitive data at rest
• Follow OWASP mobile security guidelines

Performance

• Use lazy loading for lists
• Implement efficient SwiftData queries
• Minimize view updates with proper state management
• Profile and optimize widget updates

Available Detailed Skills

The project includes specialized skills in .claude/skills/:

• project-context.md – Project overview and navigation
• mvvm-architecture.md – Architecture patterns and guidelines
• swiftui.md – SwiftUI best practices
• swiftdata.md – Data persistence patterns
• service-layer.md – Service implementation guidelines
• subscription-expense.md – Business logic for subscriptions/expenses
• widgets.md – WidgetKit implementation
• notifications.md – Notification handling
• security.md – Security best practices
• accessibility.md – Accessibility standards
• performance.md – Performance optimization
• testing.md – Testing strategies
• error-handling.md – Error management
• ui-design.md – UI/UX guidelines
• code-review.md – Code review checklist

Example Usage

When adding a new feature:

1. Review project-context.md for structure
2. Follow patterns in mvvm-architecture.md
3. Implement using swiftui.md and swiftdata.md guidelines
4. Add tests per testing.md
5. Ensure accessibility.md compliance
6. Review against code-review.md checklist