# Task: TypeScript Generation Options

## Related Documents
- Analysis: `docs/analysis/feature-enhancements-analysis.md`
- Branch: `feature/typescript-options` (from `dev`)

## Priority
NORMAL

## Objective
Add configurable options to the `generate-types` tool for customizing TypeScript output format, including enum style, interface naming conventions, and indentation preferences.

## Definition of Done
- [x] Code implemented per specification
- [x] TypeScript compilation CLEAN
- [x] Lint checks PASSED (no lint script in project)
- [x] ALL tests passing
- [x] Manual verification with petstore spec
- [x] PROOF PROVIDED (before/after output samples)

## Scope

### IN SCOPE
- `enumAsUnion` option (default true) - generate enums as union types
- `enumAsEnum` option - generate enums as TypeScript enums
- `interfacePrefix` option - prefix for interface names (e.g., "I")
- `interfaceSuffix` option - suffix for interface names (e.g., "Type")
- `indentation` option - 2 spaces, 4 spaces, or tab
- Validation of mutually exclusive options

### OUT OF SCOPE
- `readonlyProperties` option (future enhancement)
- `exportDefault` option (future enhancement)
- `includeRefs` option (future enhancement)
- `allOptional` / `allRequired` options (future enhancement)

## Sub-Tasks

### Phase 1: Options Interface and Schema
#### 1.1 Add TypeScriptOptions interface to types.ts
- **Details**: Define interface with all option properties as optional
- **Files**: `src/lib/types.ts`
- **Testing**: TypeScript compilation

#### 1.2 Update generate tool schema with options parameter
- **Details**: Add nested options object to Zod schema
- **Files**: `src/tools/generate.ts`
- **Testing**: Parse spec with invalid options should fail

### Phase 2: Enum Generation Modes
#### 2.1 Implement enumAsEnum generation
- **Details**: Convert `type X = 'a' | 'b'` to `enum X { A = 'a', B = 'b' }`
- **Files**: `src/tools/generate.ts`
- **Testing**: Generate with enumAsEnum=true

#### 2.2 Add mutual exclusion validation
- **Details**: Error if both enumAsUnion and enumAsEnum are true
- **Files**: `src/tools/generate.ts`
- **Testing**: Should reject invalid combination

### Phase 3: Interface Naming
#### 3.1 Implement prefix/suffix application
- **Details**: Apply prefix/suffix to interface names during generation
- **Files**: `src/tools/generate.ts`
- **Testing**: interfacePrefix='I' produces `interface IPet`

#### 3.2 Handle sanitized names with prefix/suffix
- **Details**: Ensure prefix/suffix works with .NET sanitized names
- **Files**: `src/tools/generate.ts`
- **Testing**: `Namespace.Type` with prefix='I' produces `IType`

### Phase 4: Indentation Options
#### 4.1 Implement indentation configuration
- **Details**: Support '2', '4', 'tab' options for generated code
- **Files**: `src/tools/generate.ts`
- **Testing**: Generate with each option, verify output

## Files to Modify
- `src/lib/types.ts`: Add `TypeScriptOptions` interface
- `src/tools/generate.ts`: Update schema, implement option handling in schemaToType() and generateTypes()

## Risks & Mitigations

| Risk | Impact | Mitigation |
|------|--------|------------|
| Invalid option combinations | LOW | Validate at handler entry, return clear error |
| Breaking existing behavior | LOW | All options optional with current defaults |
| Enum PascalCase conversion edge cases | MEDIUM | Use robust capitalizeFirst function |

## Testing Strategy
- Build: `npm run build` - must pass
- Manual: Test with petstore spec using various option combinations
- Verification commands:
  ```bash
  # Default (current behavior)
  echo '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"generate-types","arguments":{"path":"https://petstore.swagger.io/v2/swagger.json","schemas":["Pet"]}}}' | node dist/index.js

  # With enumAsEnum
  echo '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"generate-types","arguments":{"path":"https://petstore.swagger.io/v2/swagger.json","schemas":["Pet"],"options":{"enumAsEnum":true}}}}' | node dist/index.js

  # With prefix
  echo '{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"generate-types","arguments":{"path":"https://petstore.swagger.io/v2/swagger.json","schemas":["Pet"],"options":{"interfacePrefix":"I"}}}}' | node dist/index.js
  ```

## Implementation Notes

### Enum to TypeScript Enum Conversion
```typescript
// Input: enum values ['available', 'pending', 'sold']
// Output:
export enum PetStatus {
  Available = 'available',
  Pending = 'pending',
  Sold = 'sold'
}
```

Use PascalCase for enum member names:
```typescript
function toPascalCase(value: string): string {
  return value.replace(/(?:^|[_-])(\w)/g, (_, c) => c.toUpperCase());
}
```

### Indentation Implementation
```typescript
const INDENT = {
  '2': '  ',
  '4': '    ',
  'tab': '\t'
};
const indent = INDENT[options.indentation ?? '2'];
```