bbs-md/.planning/codebase/ARCHITECTURE.md

Architecture

Analysis Date: 2026-02-28

Pattern Overview

Overall: Single-Binary CLI/TUI Application (Rust)

Key Characteristics:

• Monolithic Rust binary using Ratatui for terminal UI
• Minimal dependency footprint (only Ratatui as external dependency)
• Single entry point with main function
• Early-stage project with foundational structure only

Layers

Presentation Layer:

• Purpose: Terminal user interface rendering and interaction
• Location: src/main.rs (currently)
• Contains: TUI initialization, event handling, widget rendering
• Depends on: Ratatui framework
• Used by: End users through terminal

Business Logic Layer:

• Purpose: Core application functionality
• Location: TBD - not yet implemented
• Contains: Data processing, command handling, state management
• Depends on: None currently defined
• Used by: Presentation layer

Data Layer:

• Purpose: Data persistence and retrieval
• Location: TBD - not yet implemented
• Contains: File I/O, caching, serialization
• Depends on: Standard library (File, IO)
• Used by: Business logic layer

Data Flow

Typical User Interaction Flow:

1. Terminal input captured by Ratatui event handling
2. User action (keyboard/mouse) parsed into application command
3. Command dispatched to business logic handler
4. Handler processes request, potentially reads/writes data
5. State updated based on result
6. UI re-rendered with new state in next frame

State Management:

• Single application state entity (not yet defined)
• Immutable state passed to rendering function
• Ratatui handles incremental screen updates

Key Abstractions

Terminal User Interface (TUI):

• Purpose: Encapsulate all terminal rendering and input handling
• Examples: src/main.rs (current single module)
• Pattern: React-like paradigm via Ratatui (state -> render)

Application Command/Action:

• Purpose: Abstract user intentions from input events
• Examples: Not yet implemented
• Pattern: Enum-based command pattern expected

Entry Points

Binary Entry:

• Location: src/main.rs
• Triggers: cargo run or binary execution
• Responsibilities:
  • Initialize Ratatui terminal
  • Set up event loop
  • Handle application lifecycle
  • Render UI each frame
  • Currently: Placeholder with "Hello, world!" output

Error Handling

Strategy: Not yet defined

Patterns:

• Ratatui provides Result types for I/O operations
• Expected approach: Result-based error propagation using ? operator
• Terminal restoration should be ensured on panic (Ratatui provides Drop impl)

Cross-Cutting Concerns

Logging: Not yet implemented. Standard approach would use log crate or println! macros during development.

Validation: Not yet implemented. Expected in business logic layer once commands are defined.

Terminal State: Ratatui manages terminal state (raw mode, cursor visibility, etc.). Must ensure proper cleanup on application exit.

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Architecture analysis: 2026-02-28