hosts/memory-bank/activeContext.md

Active Context: hosts

Current Work Focus

Project Initialization Phase: Setting up the foundational structure for the hosts TUI application. The project is in its earliest stage with basic uv configuration and placeholder code.

Recent Changes

Memory Bank Initialization

• Created complete memory bank structure with all core files
• Documented project vision, technical context, and system architecture
• Established clear patterns and design decisions for implementation

Current Project State

• Basic uv project with Python 3.13 requirement
• Minimal main.py with placeholder "Hello from hosts!" message
• ruff configured as the only dependency
• Project structure planned but not yet implemented

Next Steps

Immediate Priorities (Phase 1)

1. Set up proper project structure:

   • Create src/hosts/ package directory
   • Move main.py to proper location
   • Add __init__.py files

2. Add core dependencies:

   • Add textual for TUI framework
   • Add pytest for testing
   • Configure project entry point in pyproject.toml

3. Implement basic data models:

   • Create src/hosts/core/models.py with HostEntry and HostsFile classes
   • Implement basic validation logic
   • Add type hints and docstrings

4. Create hosts file parser:

   • Implement src/hosts/core/parser.py
   • Handle comments, active/inactive entries
   • Parse existing /etc/hosts format

Phase 2 Priorities

1. Basic TUI implementation:

   • Create main application class
   • Implement two-pane layout
   • Add entry list view

2. Read-only functionality:

   • Load and display hosts file
   • Navigate between entries
   • Show entry details

3. Testing foundation:

   • Set up pytest configuration
   • Create test fixtures for sample hosts files
   • Implement parser tests

Active Decisions and Considerations

Architecture Decisions Made

• Layered architecture: TUI → Manager → Core → System layers
• Command pattern: For undo/redo functionality
• Immutable state: All operations return new state
• Permission model: Explicit edit mode with sudo management

Design Patterns Chosen

• Observer pattern: For state change notifications
• Factory pattern: For parser creation
• Command pattern: For operations with undo capability

Technical Constraints Acknowledged

• Python 3.13+: Using modern Python features
• Unix-like systems: Primary target (Linux, macOS)
• Root access: Required for /etc/hosts modifications
• File integrity: Must preserve existing structure

Important Patterns and Preferences

Code Organization

• Separation of concerns: Clear layer boundaries
• Type safety: Comprehensive type hints
• Documentation: Docstrings for all public APIs
• Testing: TDD approach with high coverage

User Experience Priorities

• Safety first: Read-only by default, explicit edit mode
• Keyboard-driven: Efficient navigation without mouse
• Visual clarity: Clear active/inactive indicators
• Error prevention: Validation before any file writes

Development Workflow

• uv for everything: Package management and execution
• ruff for quality: Linting and formatting
• pytest for testing: Comprehensive test coverage
• Incremental development: Build and test each component

Learnings and Project Insights

Key Insights from Planning

1. Permission management is critical: The sudo handling needs careful design
2. File integrity is paramount: Users trust their hosts file
3. DNS integration adds complexity: But provides significant value
4. TUI responsiveness matters: No blocking operations in UI thread

Risk Areas Identified

• Permission escalation: Security implications of sudo usage
• File corruption: Atomic writes and validation essential
• Cross-platform compatibility: Different hosts file locations
• Large file performance: Memory usage with many entries

Success Factors

• Clear separation of read/write modes: Reduces accidental changes
• Comprehensive validation: Prevents invalid configurations
• Intuitive keyboard shortcuts: Faster than manual editing
• Visual feedback: Users always know current state

Current Development Environment

Tools Ready

• uv: Package manager configured
• ruff: Code quality tool available
• Python 3.13: Runtime environment set

Next Tool Additions Needed

• textual: TUI framework (primary dependency)
• pytest: Testing framework
• textual.testing: TUI testing utilities

Project Structure Status

• Current: Flat structure with main.py
• Target: Proper package structure in src/hosts/
• Migration needed: Move and reorganize files

This active context represents the current state as we begin actual implementation of the hosts TUI application.