# Progress: hosts-go

## What Works

### ✅ Memory Bank Foundation
- **Project documentation**: Complete memory bank structure established
- **Architecture planning**: Clear technical design documented
- **Development approach**: TDD strategy and patterns defined
- **Technology stack**: Bubble Tea ecosystem selected and documented

### ✅ Project Definition
- **Core requirements**: Two-pane TUI for hosts file management clearly defined
- **User experience**: Safety-first approach with explicit edit mode
- **Technical constraints**: Permission model and file safety requirements established
- **Directory structure**: Planned layout for Go project organization

### ✅ Foundation Implementation (COMPLETED)
- **Go module initialization**: ✅ `go.mod` created with all core dependencies
- **Directory structure**: ✅ Complete project structure (`cmd/`, `internal/`, `tests/`)
- **Core data models**: ✅ `internal/core/models.go` with HostEntry and HostsFile structs
- **Validation system**: ✅ IP address and hostname validation with RFC compliance
- **Test suite**: ✅ Comprehensive tests (44 test cases, 100% passing)
- **Demo application**: ✅ Working `cmd/hosts/main.go` demonstrating functionality

### ✅ Phase 1: Core Functionality (COMPLETED)
- **Hosts file parser**: ✅ Complete `internal/core/parser.go` implementation
- **Intelligent formatting**: ✅ Adaptive spacing and column alignment with GCD-based detection
- **File operations**: ✅ Safe backup and atomic write operations
- **Test coverage**: ✅ 54 comprehensive tests (100% passing)
- **Demo application**: ✅ Full working demonstration with real-world examples
- **Parser capabilities**:
  - ✅ **Standard entries**: IPv4, IPv6, multiple aliases, inline comments
  - ✅ **Comment handling**: Disabled entries vs standalone comments with perfect classification
  - ✅ **Error recovery**: Malformed line handling with non-fatal warnings
  - ✅ **Format preservation**: Round-trip parsing maintains style while improving alignment
  - ✅ **Style detection**: GCD-based tab/space analysis with intelligent column widths
  - ✅ **Search functionality**: Find entries by hostname or alias with O(1) performance
- **Safety features**:
  - ✅ **Backup system**: Timestamped backups in `~/.config/hosts-go/` directory
  - ✅ **Atomic operations**: Temporary files with rollback capability prevent corruption
  - ✅ **Validation layers**: Comprehensive IP and hostname validation with clear messages
  - ✅ **Warning system**: Non-fatal issues reported gracefully without stopping parsing
  - ✅ **Format intelligence**: Automatic detection and preservation of original formatting style

## What's Left to Build

### 🎨 Basic TUI (Phase 2 - Current Priority)
- [x] **Main Bubble Tea model**: Core application state and structure
- [x] **Two-pane layout**: Left list + right detail view
- [x] **Entry list display**: Show IP and hostname columns
- [x] **Entry selection**: Navigate and select entries with keyboard
- [ ] **View mode**: Safe browsing with status indicators
- [ ] **Integration**: Connect TUI with existing parser functionality

### 🔧 Edit Functionality (Phase 3)
- [ ] **Edit mode transition**: Explicit mode switching with visual indicators
- [ ] **Permission handling**: Request sudo access when entering edit mode
- [ ] **Entry modification**: Add, edit, delete, toggle active status
- [ ] **File writing**: Atomic updates with backup and rollback
- [ ] **Input validation**: Real-time validation of IP and hostname inputs

### 🌐 Advanced Features (Phase 4)
- [ ] **DNS resolution**: Background hostname to IP resolution
- [ ] **IP comparison**: Compare resolved vs current IP addresses
- [ ] **Entry reordering**: Manual drag/drop or move commands
- [ ] **Sorting options**: Sort by IP, hostname, or custom order
- [ ] **Search/filter**: Find entries quickly in large files

### 🧪 Testing & Quality (Ongoing)
- [ ] **TUI tests**: User interactions, state transitions
- [ ] **Integration tests**: Complete TUI workflows with file operations
- [ ] **Permission tests**: sudo scenarios, graceful degradation
- [ ] **End-to-end tests**: Full application workflows

## Current Status

### Project Phase: **Phase 1 Complete → Phase 2 (TUI Implementation)**
- **Completion**: ~65% (foundation and complete core parser functionality implemented)
- **Active work**: Ready to implement Bubble Tea TUI with two-pane layout (Phase 2)
- **Blockers**: None - comprehensive parser foundation with 54 tests completed
- **Parser status**: Production-ready with all safety features implemented

### Development Readiness
- ✅ **Architecture designed**: Clear technical approach documented
- ✅ **Requirements defined**: User experience and functionality specified  
- ✅ **Technology selected**: Bubble Tea stack confirmed and installed
- ✅ **Testing strategy**: TDD approach implemented and proven
- ✅ **Project scaffolding**: Complete Go module with all dependencies
- ✅ **Development environment**: Fully functional with comprehensive tests
- ✅ **Parser foundation**: Robust, tested, and production-ready

### Risk Assessment
- **Low risk**: Well-established technology stack (Go + Bubble Tea)
- **Low risk**: Core parsing functionality (thoroughly tested and working)
- **Medium risk**: TUI complexity with two-pane layout
- **Medium risk**: Permission handling complexity (sudo integration)
- **Low risk**: TUI responsiveness (parser handles large files efficiently)

## Known Issues

### Technical Challenges
- **Permission elevation**: Need to handle sudo gracefully across platforms
- **File locking**: Prevent concurrent modifications to `/etc/hosts`
- **Large file performance**: Ensure responsiveness with large hosts files
- **Terminal compatibility**: Test across different terminal applications

### Implementation Decisions Needed
- **Configuration storage**: Where to store user preferences and settings
- **Backup strategy**: How many backups to keep and where to store them
- **DNS timeout handling**: How to handle slow or unresponsive DNS queries
- **Error recovery**: How to handle corrupted hosts files or write failures

## Evolution of Project Decisions

### Initial Scope
- Started with comprehensive feature set including DNS resolution
- Planned for cross-platform compatibility from day one
- Emphasized safety and validation throughout

### Refined Approach
- **TDD emphasis**: Write tests first to ensure reliability
- **Incremental development**: Build core functionality before advanced features
- **Safety first**: Default to read-only mode, explicit edit mode transition
- **User experience focus**: Two-pane interface for efficiency

### Technology Evolution
- **Framework choice**: Bubble Tea selected for maturity and documentation
- **Architecture pattern**: MVU pattern from Bubble Tea ecosystem
- **Testing approach**: Comprehensive coverage with mocked dependencies
- **Development workflow**: Standard Go tooling with additional quality tools

## Success Metrics & Milestones

### Milestone 1: Basic Functionality (Target: Week 1)
- [ ] Parse and display existing hosts file entries
- [ ] Navigate entries with keyboard
- [ ] View entry details in right pane
- **Success criteria**: Can safely browse hosts file without editing

### Milestone 2: Core Editing (Target: Week 2)  
- [ ] Toggle entries active/inactive
- [ ] Add new entries with validation
- [ ] Edit existing entries
- **Success criteria**: Can perform basic hosts file modifications safely

### Milestone 3: Advanced Features (Target: Week 3)
- [ ] DNS resolution and IP updates
- [ ] Entry reordering and sorting
- [ ] Search and filtering
- **Success criteria**: Full feature parity with manual editing plus enhancements

### Milestone 4: Polish & Release (Target: Week 4)
- [ ] Comprehensive testing and bug fixes
- [ ] Documentation and usage examples
- [ ] Cross-platform testing and compatibility
- **Success criteria**: Production-ready tool suitable for daily use

## Next Immediate Actions

### ✅ COMPLETED Phase 1 Tasks
1. ✅ **Initialize Go project** (`go mod init hosts-go`)
2. ✅ **Add core dependencies** (Bubble Tea, Bubbles, Lip Gloss, testify)
3. ✅ **Create directory structure** according to projectbrief.md
4. ✅ **Create core data models** with comprehensive validation (`internal/core/models.go`)
5. ✅ **Implement foundation test suite** (44 model tests, 100% passing)
6. ✅ **Create demo application** proving foundation works (`cmd/hosts/main.go`)
7. ✅ **Write comprehensive parser tests** (54 total tests covering all scenarios)
8. ✅ **Implement hosts file parser** (`internal/core/parser.go` - complete implementation)
9. ✅ **Add intelligent formatting system** with GCD-based spacing detection
10. ✅ **Implement safe file operations** with backup and atomic writes
11. ✅ **Handle edge cases** (malformed entries, various formats, error recovery)
12. ✅ **Test round-trip parsing** (parse → format → parse consistency verified)
13. ✅ **Update demo application** showcasing all parser functionality with realistic examples
14. ✅ **Implement search functionality** (FindEntry method for hostname/alias lookup)
15. ✅ **Add format style detection** (automatic tab vs space detection with column widths)
16. ✅ **Create backup system** (timestamped backups in `~/.config/hosts-go/`)
17. ✅ **Validate all parser features** (IPv4, IPv6, aliases, comments, disabled entries)
18. ✅ **Test warning system** (malformed lines handled gracefully)
19. ✅ **Verify atomic operations** (temp files with rollback for safe writes)
20. ✅ **Complete parser documentation** (comprehensive demo showing all capabilities)

### 🚧 NEXT Phase 2 Actions (TUI Implementation)
1. **Design TUI architecture** following Bubble Tea MVU pattern
2. **Create main application model** with state management
3. **Implement two-pane layout** (entry list + detail view)
4. **Add navigation controls** (keyboard-driven interaction)
5. **Integrate parser functionality** with TUI display
6. **Implement view mode** (safe browsing without modifications)

**Phase 1 is fully complete with a production-ready parser foundation.**

### Parser Achievement Summary
- **54 comprehensive tests** covering all hosts file variations and edge cases
- **Real-world validation** with complex hosts file examples including IPv4, IPv6, aliases, comments
- **Intelligent formatting** that preserves user style while improving alignment
- **Complete safety system** with backups, atomic writes, and graceful error handling
- **Search and management** capabilities for finding and manipulating entries
- **Demo application** showcasing all functionality with realistic examples

The foundation is robust, tested, and ready for TUI implementation in Phase 2.