# Active Context

## Current Status: Phase 4 Completed Successfully! 🎉

**Last Updated:** 2025-01-17 22:26 CET

## Recent Achievement
Successfully completed **Phase 4: Import/Export System** implementation! All 279 tests are now passing, representing a major milestone in the hosts TUI application development.

### Phase 4 Implementation Summary
- ✅ **Complete Import/Export Service** (`src/hosts/core/import_export.py`)
  - Multi-format support: HOSTS, JSON, CSV
  - Comprehensive validation and error handling
  - DNS entry support with proper validation workarounds
  - Export/import roundtrip data integrity verification
  - File format auto-detection and path validation

- ✅ **Comprehensive Test Coverage** (`tests/test_import_export.py`)
  - 24 comprehensive tests covering all functionality
  - Export/import roundtrips for all formats
  - Error handling for malformed files
  - DNS entry creation with validation workarounds
  - All tests passing with robust error scenarios covered

- ✅ **DNS Entry Validation Fix**
  - Resolved DNS entry creation issues in import methods
  - Implemented temporary IP workaround for DNS-only entries
  - Fixed class name issues (`HostsParser` vs `HostsFileParser`)
  - Fixed export method to use parser serialization properly

## Current System Status
- **Total Tests:** 279 passed, 5 warnings (non-critical async mock warnings)
- **Test Coverage:** Complete across all core modules
- **Code Quality:** All ruff checks passing
- **Architecture:** Clean, modular, well-documented

## Completed Phases
1. ✅ **Phase 1: DNS Resolution Foundation** - DNS service, fields, and comprehensive testing
2. ✅ **Phase 2: DNS Integration** - TUI integration, status widgets, and real-time updates
3. ✅ **Phase 3: Advanced Filtering** - Status-based, DNS-type, and search filtering with presets
4. ✅ **Phase 4: Import/Export System** - Multi-format import/export with validation and testing

## Next Phase: Phase 5 - DNS Name Support
Focus on enhancing entry modals and editing functionality to fully support DNS names alongside IP addresses:

### Phase 5 Priorities
1. **Update AddEntryModal** (`src/hosts/tui/add_entry_modal.py`)
   - Add DNS name field option
   - Implement mutual exclusion logic (IP vs DNS name)
   - Add field deactivation when DNS name is present

2. **Enhance EditHandler** (`src/hosts/tui/edit_handler.py`)
   - Support DNS name editing
   - IP field deactivation logic
   - Enhanced validation for DNS entries

3. **Parser DNS Metadata** (`src/hosts/core/parser.py`)
   - Handle DNS name metadata in hosts file comments
   - Preserve DNS information during file operations

4. **Validation Improvements**
   - Enhanced mutual exclusion validation
   - DNS name format validation
   - Error handling for invalid combinations

## Technical Architecture Status
- **DNS Resolution Service:** Fully operational with background/manual refresh
- **Advanced Filtering:** Complete with preset management
- **Import/Export:** Multi-format support with comprehensive validation
- **TUI Integration:** Professional interface with modal dialogs
- **Data Models:** Enhanced with DNS fields and validation
- **Test Coverage:** Comprehensive across all modules

## Key Technical Insights
- DNS entry creation requires temporary IP workaround due to validation constraints
- Parser class naming conventions are critical for import functionality
- Export/import roundtrip validation ensures data integrity
- Background DNS resolution integrates seamlessly with TUI updates
- Filter system handles complex DNS entry scenarios effectively

## Development Patterns Established
- Test-Driven Development with comprehensive coverage
- Modular architecture with clear separation of concerns
- Consistent error handling and validation patterns
- Professional TUI design with modal dialogs
- Clean async integration for DNS operations