# Dart Language Support - Implementation Summary

## Overview

This document describes the implementation of Dart language support in SunLint. The implementation follows the plan outlined in `DART_SUPPORT_PLAN.md` and maintains full backward compatibility with TypeScript/JavaScript analysis.

## Architecture

```
┌─────────────────────────────────────────────────────────────────┐
│  SunLint CLI (TypeScript)                                       │
│  - Config Management                                            │
│  - File Targeting                                               │
│  - Analysis Orchestration                                       │
│  - Report Generation                                            │
└────────┬────────────────────────────────────────────────────────┘
         │
         ├─► SemanticEngineManager (NEW)
         │   ├── TypeScriptAnalyzer (wrapper around SemanticEngine)
         │   │   └─ For .ts, .tsx, .js, .jsx files
         │   │
         │   └── DartAnalyzer (NEW)
         │       └─ For .dart files
         │       └─ JSON-RPC subprocess (when binary available)
         │       └─ Regex fallback mode (when binary not available)
         │
         └─► HeuristicEngine
             ├── Uses SemanticEngineManager for multi-language support
             └── Falls back to legacy SemanticEngine for TypeScript
```

## Implemented Components

### 1. Core Interfaces

#### `core/interfaces/language-analyzer.interface.js`
- `ILanguageAnalyzer` - Abstract base class for all language analyzers
- `LanguageAnalyzerRegistry` - Manages registration and lookup of analyzers
- `getRegistry()` - Singleton accessor for the registry

Key methods:
- `initialize(config)` - Initialize the analyzer
- `analyzeFile(filePath, rules, options)` - Analyze a single file
- `getSymbolTable(filePath)` - Get symbol table for semantic analysis
- `supportsFile(filePath)` - Check if file is supported

### 2. Semantic Engine Manager

#### `core/semantic-engine-manager.js`
- `SemanticEngineManager` - Coordinates multiple language analyzers
- `getManager(options)` - Singleton accessor
- `resetManager()` - Reset singleton (for testing)

Key methods:
- `registerAnalyzer(analyzer)` - Register a language analyzer
- `initialize(projectPath, targetFiles)` - Initialize all analyzers
- `getSymbolTable(filePath)` - Route to appropriate analyzer
- `analyzeFile/analyzeFiles()` - Analyze files with correct analyzer
- `groupFilesByAnalyzer(files)` - Group files by their analyzer

### 3. Language Analyzers

#### `core/adapters/typescript-analyzer.js`
- Wraps existing `SemanticEngine` (ts-morph)
- Supports: `.ts`, `.tsx`, `.js`, `.jsx`, `.mts`, `.cts`, `.mjs`, `.cjs`
- Full backward compatibility with existing semantic rules

#### `core/adapters/dart-analyzer.js`
- New Dart language analyzer
- Supports: `.dart`
- Two operation modes:
  1. **Binary mode**: Communicates with Dart analyzer binary via JSON-RPC
  2. **Fallback mode**: Uses regex-based analysis when binary not available

Binary resolution priority:
1. Bundled binary: `bin/sunlint-dart-{platform}`
2. Cached binary: `~/.sunlint/bin/sunlint-dart-{platform}`
3. Dart SDK: `dart pub global run` (future)
4. Fallback: Regex-based analysis

Built-in Dart patterns:
- `N001` - Naming conventions (UpperCamelCase for classes, lowerCamelCase for variables)
- `E001` - Empty catch blocks
- `S003` - Sensitive data in print statements
- `S022` - String interpolation (potential XSS)

### 4. Analyzer Registration

#### `core/adapters/index.js`
- `registerBuiltInAnalyzers(options)` - Register all built-in analyzers
- `getSupportedLanguages()` - Get list of supported languages
- `getAnalyzerClass(language)` - Get analyzer class for a language

### 5. Heuristic Engine Updates

#### `engines/heuristic-engine.js`
Updated to support multi-language analysis:

```javascript
// Constructor additions
this.semanticEngineManager = null;

// initializeSymbolTable() changes
- Register built-in analyzers
- Initialize SemanticEngineManager
- Keep legacy SemanticEngine for backward compatibility

// New methods
getSemanticEngineManager() - Get the manager instance
getLanguageAnalyzer(language) - Get specific analyzer
getSymbolTableForFile(filePath) - Route to correct analyzer

// Cleanup
- Cleanup SemanticEngineManager
- Cleanup legacy SemanticEngine
```

## File Targeting

The `FileTargetingService` already supports Dart files:
- Extension: `.dart`
- Excluded patterns: `*.g.dart`, `*.freezed.dart`, `*.mocks.dart` (generated files)

## Usage

### CLI Usage

```bash
# Analyze Dart files
sunlint --input="lib/" --include="**/*.dart"

# Analyze mixed project (TypeScript + Dart)
sunlint --input="src/" --include="**/*.{ts,tsx,dart}"

# With verbose output
sunlint --input="lib/" --include="**/*.dart" --verbose
```

### Programmatic Usage

```javascript
const { getManager } = require('sunlint/core/semantic-engine-manager');
const { registerBuiltInAnalyzers } = require('sunlint/core/adapters');

// Register analyzers
registerBuiltInAnalyzers({ verbose: true });

// Get manager
const manager = getManager();

// Initialize
await manager.initialize('/path/to/project', targetFiles);

// Get symbol table for any file type
const symbolTable = await manager.getSymbolTable('/path/to/file.dart');

// Analyze files
const violations = await manager.analyzeFile(filePath, rules, options);
```

## Testing

Run unit tests:
```bash
node test/unit/dart-support.test.js
```

Test coverage:
- ✅ ILanguageAnalyzer interface abstraction
- ✅ TypeScriptAnalyzer creation and file support
- ✅ DartAnalyzer creation and file support
- ✅ LanguageAnalyzerRegistry registration and lookup
- ✅ SemanticEngineManager initialization
- ✅ File grouping by analyzer
- ✅ DartAnalyzer regex patterns
- ✅ DartAnalyzer basic symbol table extraction

## Backward Compatibility

All existing functionality is preserved:
- ✅ TypeScript/JavaScript analysis works unchanged
- ✅ Existing semantic rules work unchanged
- ✅ Configuration format unchanged
- ✅ CLI options unchanged
- ✅ Report format unchanged

## Future Work (Phase 2-6)

### Phase 2: Dart Analyzer Binary
- Create Dart project with JSON-RPC server
- Implement full AST analysis
- Cross-compile for Linux, macOS, Windows

### Phase 3-4: Build & Distribution
- GitHub Actions for binary compilation
- npm package with embedded binaries
- Post-install verification

### Phase 5: Dart Rules
Priority rules to port:
- C001 - High Cyclomatic Complexity
- C002 - Duplicate Code Detection
- C008 - Deep Nesting
- N001 - Naming Convention Violations
- E001 - Missing Error Handling

### Phase 6: Documentation
- Dart-specific user guide
- Flutter project examples
- CI/CD integration examples

## Files Created/Modified

### New Files
- `core/interfaces/language-analyzer.interface.js`
- `core/semantic-engine-manager.js`
- `core/adapters/typescript-analyzer.js`
- `core/adapters/dart-analyzer.js`
- `core/adapters/index.js`
- `test/unit/dart-support.test.js`
- `test/dart-fixtures/sample.dart`
- `docs/DART_SUPPORT_IMPLEMENTATION.md`

### Modified Files
- `engines/heuristic-engine.js`
  - Added imports for multi-language support
  - Added `semanticEngineManager` property
  - Updated `initializeSymbolTable()` to use SemanticEngineManager
  - Added helper methods: `getSemanticEngineManager()`, `getLanguageAnalyzer()`, `getSymbolTableForFile()`
  - Updated `cleanup()` to dispose managers

## Verification

```bash
# Verify TypeScript still works
node cli.js --rule=S003 --input="./core" --include="**/*.js" --engine=heuristic --max-files=5

# Verify Dart support
node cli.js --rule=N001 --input="./test/dart-fixtures" --include="**/*.dart" --verbose

# Run unit tests
node test/unit/dart-support.test.js
```

All verifications pass successfully.