How paulononaka/the_classic_movies_app_example works
<explanation>
Below is a step‑by‑step guide to creating a detailed and accurate system design diagram for “The Classic Movies App,” a Flutter‑based, modular monorepo. Follow these instructions to capture all essential components, interactions, and architectural patterns.
1. Identify the Project Type and Purpose
- This is a full‑stack (multi‑platform) Flutter application using a monorepo structure managed by Melos.
- It targets Android, iOS, and Web, and is composed of three main packages:
• core (shared services, utilities, DI)
• design_system (UI components, themes, i18n)
• movies (feature module: domain, data sources, UI pages)
- The main_app (in apps/) ties everything together, injecting dependencies and launching the UI.
2. Main Components to Represent
- Client Platforms: Android, iOS, Web
- Flutter Engine / MainApp
- Feature Modules (packages):
• Core Module
• DesignSystem Module
• Movies Module
- External Services:
• TMDB REST API
• Sentry (Error Monitoring)
• Firebase (Auth, Analytics, Messaging)
- Local Persistence: Hive DB
- Dependency Injection Container (get_it)
- Navigation Layer (go_router)
3. Relationships and Data Flows
- User taps UI → Flutter Widget (DesignSystem) → GoRouter → MoviesController
- MoviesController → MoviesRepository (domain) →
○ RemoteDataSource → HTTP calls to TMDB
○ LocalDataSource → Hive local database
- Core services (SentryService, FeatureToggleService, SessionTrackerService) register with DI container; accessed by any module.
- Firebase SDK is initialized at startup (via firebase_options.dart) and used by core/infrastructure.
4. Architectural Patterns & Design Principles
- Modular Monorepo: clear separation into packages for reuse and isolation.
- Clean architecture within each feature: Presentation → Domain → Data → Infrastructure
- Dependency Injection: all services and repositories registered in get_it at app bootstrap.
- Layered navigation: go_router defines routes in movies/routes.
- Localization: arb files in core/design_system/movies for i18n.
- CI/CD: GitHub Actions pipeline configured via .github/workflows.
5. Diagram Elements & Notation
a. Shapes & Colors
- Rectangles (rounded for modules—Core, DesignSystem, Movies)
- Cylinders for databases (Hive)
- Clouds for external services (TMDB API, Firebase, Sentry)
- Light colors by layer (e.g., blue=UI, green=domain, orange=data, gray=core)
b. Labels & Arrows
- Label each component clearly (e.g., “MoviesRepository”, “Hive DB”)
- Directional arrows for data flow (solid for sync calls, dashed for asynchronous events)
- Annotate arrows with protocols or libraries (e.g., “REST/HTTP”, “Hive API”, “get_it DI”)
c. Grouping
- Visually group Android/iOS/Web platforms at the top feeding into the same Flutter Engine block.
- Enclose each package as a boundary box showing internal structure (sub‑packages: services, data_sources, pages).
d. Legend
- Include a small legend explaining color coding, arrow styles, and shape meanings.
6. Tailoring to This Mono‑repo Flutter App
- Emphasize that the “MainApp” layer is a thin shell that imports and composes the three packages.
- Show melos.yaml at the root as orchestrator for bootstrapping and codegen—optionally annotate that Melos drives dependency resolution across packages.
- Highlight platform‑specific folders (android/, ios/, web/) only to show that they host the native wrappers; no deep dive into native code.
7. Detailed Component Breakdown (to include in diagram)
- MainApp
• main.dart → initializes Firebase, Sentry, DI container, runs App() widget
- Core Module
• Env (reads .env)
• Services: FeatureToggleService, SentryService, SessionTrackerService
• Logger (mca_logger.dart)
- DesignSystem Module
• UI Components: MovieListItem, AppErrorWidget, LoadingWidget…
• Theme Provider & Extensions
• Localization sub‑module
- Movies Module
• Presentation: movies_page, movies_controller, movie_details_page
• Domain: MoviesRepository interface, DataSource interfaces
• Data: MoviesRepositoryImpl, MoviesRemoteDataSourceImpl (HTTP), MoviesLocalDataSourceImpl (Hive)
• Infrastructure: HiveService, movies_dependencies.dart
• DI registration in movies_dependencies.dart
- External & Persistence
• TMDB API (REST)
• Hive (local DB)
• Sentry (error monitoring)
• Firebase (Analytics, Auth)
8. Final Diagram Checklist
- [ ] All packages/modules shown as separate bounded boxes
- [ ] Sub‑components (services, controllers, repositories) shown inside their package boxes
- [ ] External services as clouds, with arrows indicating calls or event streams
- [ ] Annotation of protocols (HTTP, WebSockets if any, Hive API calls)
- [ ] DI container icon at the center of the app layer, with arrows to registered services
- [ ] Navigation layer (go_router) between UI and controllers, labeled accordingly
- [ ] Legend, shapes, and color key
By following these steps and laying out your diagram accordingly, you will provide a comprehensive, accurate, and easy‑to‑understand architectural view of The Classic Movies App, tailored to its modular Flutter monorepo structure.
</explanation>