Overall Architecture and Layer Description

DocuSnap-Frontend adopts the MVVM (Model-View-ViewModel) architecture pattern, combined with the Repository pattern and a layered architecture. This approach ensures a clear separation of concerns and improves maintainability.

Architecture Diagram

Note: The architecture diagram shows the relationships between different layers and components of the application.

Layer Description

The application is divided into the following layers:

UI Layer

Responsibility: Build user interfaces, handle user interactions, display data

Main Components:

• MainActivity: Main entry point of the application
• JetpackCompose UI components: Build declarative UIs
• Navigation components: Manage screen navigation

ViewModel Layer

Responsibility: Manage UI state, handle business logic, connect UI and data layers

Main Components:

• DocumentViewModel: Manage document-related operations and state
• ImageProcessingViewModel: Handle image processing logic and state

Repository Layer

Responsibility: Abstract data access logic, coordinate multiple data sources

Main Components:

• DocumentRepository: Provide document data access interface

Service Layer

Responsibility: Provide specific functional services, handle background operations

Main Components:

• DeviceDBService: Local database service
• JobPollingService: Backend job polling service
• BackendApiService: Backend API communication service
• ImageProcService: Image processing service

Data Layer

Responsibility: Provide data storage and access

Main Components:

• Room Database: Local data storage
• Backend API: Remote service interface

Data Flow

Data in the application follows a unidirectional flow principle:

1. User interactions in the UI layer trigger actions in the ViewModel layer
2. The ViewModel layer processes these actions and requests data from the Repository layer
3. The Repository layer retrieves data from either local or remote data sources
4. The data flows back through the Repository to the ViewModel
5. The ViewModel updates its state, which is observed by the UI layer
6. The UI layer automatically updates to reflect the new state

This architecture provides a clear separation of concerns, improves testability, and enhances maintainability of the application.