📈 MBStockApp

MBStockApp is a modern iOS application that provides real-time stock market summaries and quote details. Built using SwiftUI, Combine, and Clean Architecture, it focuses on modularity, testability, and a smooth user experience.

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🚀 Features

• 🔍 Searchable stock market index list
• 💹 Real-time price updates every 8 seconds
• ✅ Market summary and detailed quote screen
• 🌙 Always in Dark Mode
• 📱 Built entirely with SwiftUI and Combine
• 🧪 Includes complete unit test coverage

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🧱 Architecture (Deep Dive)

MBStockApp is built using Clean Architecture principles. Each layer has a dedicated responsibility, which improves testability, scalability, and future flexibility.

🔁 Layered Flow Overview

• View (SwiftUI)
  Displays the UI and binds to state via ViewModel. ↓
• ViewModel (State, Binding)
  Contains logic for managing view state, search, and timers. ↓
• UseCase (Scenario-Specific Logic)
  Executes a specific action like fetching market data. ↓
• Repository (Bridge, Transformation)
  Maps and transforms data from the source for the use case. ↓
• DataSource (Concrete Data Access)
  Provides raw data (e.g., from an API or local cache).

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1. View Layer (UI)

• Built with SwiftUI.
• Displays data and listens to state changes from the ViewModel.
• Stateless and reactive — no business logic.
• Handles search bar, navigation stack, loading states, and refresh visuals.
• Examples: MarketSummaryView, MarketRowView, MarketListView

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2. ViewModel Layer (Presentation Logic)

• Uses Combine for reactive state management.
• Handles user interaction, search text debounce, and auto-refresh.
• Calls the appropriate UseCase and updates @Published properties.
• Maintains UI-specific state such as:
  • .summaries
  • .filteredSummaries
  • .searchText
  • .state
• Example: MarketSummaryViewModel

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3. UseCase Layer (Scenario Logic)

• Represents a single business operation (e.g., fetching a market summary).
• Contains no UI or data source logic.
• Easy to test and reuse across features.
• One use case per user scenario — separation ensures lean and focused business logic.
• Example: GetMarketSummaryUseCase

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4. Repository Layer (Bridge + Mapper)

• Acts as a bridge between UseCases and DataSources.
• Transforms raw data into domain-specific models.
• Keeps UseCases unaware of the data source (network, cache, local).
• Why have it?
  • Encapsulates logic for transforming remote models to domain models.
  • Can combine multiple DataSources if needed (e.g., cache + API).
  • Future-proof: changing the backend affects only this layer.
• Example: DefaultMarketRepository

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5. DataSource Layer (Low-Level Data Access)

• Provides raw data from remote or local sources.
• Can simulate results using MarketDataSourceMock, or connect to an actual API in future.
• Why this layer exists:
  • It separates the implementation (e.g., HTTP, database) from the rest of the app.
  • Future support for both local (CoreData/Realm) and remote (REST/GraphQL) sources.
  • Keeps the Repository and UseCase code clean and focused on app logic, not I/O.
• Example: MarketDataSourceMock, MarketQuoteResponseModel, etc.

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📦 Technologies Used

• Swift 5.10 / Swift 6 ready
• SwiftUI
• Combine
• XCTest (unit testing)
• SwiftLint
• Swinject for Dependency Injection

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📁 Project Structure

MBStockApp/
├── Core/                        → Dependency Injection, Routing, Extensions, Logger
│   ├── DI/                      → Swinject container and DI setup
│   ├── Extensions/              → Helper extensions (e.g. Double+String)
│   ├── Routing/                 → App-wide navigation system
│   └── Utils/                   → Logger, helpers, etc.

├── Data/                        → API integration and mappers
│   ├── Constants/               → Static keys, enums, etc.
│   ├── Mappers/                 → DTO → Domain mappers
│   ├── Model/                   → DTOs from API responses
│   ├── Networking/              → HTTP services
│   ├── Repository/              → Implementation of `MarketRepository`
│   └── DataSource/Remote/       → Concrete remote data source (e.g., MarketsDataSource)

├── Domain/                      → Pure business logic
│   ├── Entity/                  → Domain models like `MarketSummary`, `MarketQuote`
│   ├── Errors/                  → Custom app/domain errors
│   ├── Repository/              → Abstract protocol for MarketRepository
│   └── UseCase/                 → Use case logic (e.g., `GetMarketSummaryUC`)

├── Localisation/                → App-localized strings
│   └── Localizable/             → `Localizable.strings` and access helpers

├── Presentation/                → UI-specific logic and structure
│   ├── Core/ViewModel/          → ViewModels not tied to specific screens
│   └── Screens/
│       └── Market/
│           ├── Destination/     → Navigation enums or routing logic
│           ├── ViewModels/      → ViewModels for each screen
│           └── Views/           → SwiftUI screens

├── ReusableViews/               → Reusable UI components (e.g., `MarketRowView`, `BaseStateView`)

├── Resources/Assets/            → Images, icons, app branding

├── MBStockAppApp/               → App entry point (e.g., `@main`, Swinject setup)
├── MBStockAppTests/             → Unit tests
├── MBStockAppUITests/           → UI automation tests

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🧪 Running Tests

MBStockApp includes unit tests for ViewModels, UseCases, and Repository logic.

To run all tests:

➤ In Xcode:

Use the following shortcut:

➤ From Terminal:

xcodebuild test -scheme MBStockApp -destination 'platform=iOS Simulator,name=iPhone 14,OS=17.4'

📇 Author

• 👨‍💻 Name: Serhan Khan
• 🌐 Website / Portfolio: [Add if available]
• 📧 Email: serhankhan0@gmail.com
• 🔗 LinkedIn: linkedin.com/in/serhan-khan-97b577103
• 🐙 GitHub: github.com/khanboy1989
• ✍️ Medium: medium.com/@serhankhan
• 🎥 YouTube: youtube.com/@SwiftwithSerhan-d7x