# Step 04 — Phase 2.3: Stylelint 适配器

**依赖**: Step 02  
**参考设计**: §3.3

## 目标

实现 CSS 的 Stylelint 适配器，用 stylelint npm 包直接检查代码。

## 前置准备

```bash
npm install --save stylelint@^17.14.0
```

## 新建文件

| # | 文件 | 说明 |
|---|------|------|
| 1 | `src/adapters/stylelint.ts` | `StylelintAdapter` |

---

## `src/adapters/stylelint.ts`

```typescript
import * as vscode from 'vscode';
import { LinterAdapter, LinterDiagnostic, AdapterResult } from '../types';

export class StylelintAdapter implements LinterAdapter {
  id = 'stylelint';
  supportedLanguages = ['css'];

  async check(document: vscode.TextDocument, _workingDir: string): Promise<AdapterResult> {
    try {
      const code = document.getText();
      const stylelint = await import('stylelint');
      const result = await stylelint.default.lint({
        code,
        codeFilename: document.uri.fsPath,
        config: { rules: {} },
      });

      const diagnostics: LinterDiagnostic[] = [];
      for (const warning of result.results[0]?.warnings ?? []) {
        const line = Math.max(0, (warning.line ?? 1) - 1);
        const column = Math.max(0, (warning.column ?? 1) - 1);
        const range = new vscode.Range(line, column, line, column + 1);
        diagnostics.push({
          severity: warning.severity === 'error' ? 'error' : 'warning',
          ruleId: `stylelint:${warning.rule}`,
          message: warning.text,
          range,
        });
      }
      return { diagnostics, status: 'ok' };
    } catch (err) {
      const message = err instanceof Error ? err.message : String(err);
      if (message.includes('Cannot find module')) {
        return { diagnostics: [], status: 'tool-unavailable', errorMessage: 'Stylelint 未安装，请执行 npm install stylelint' };
      }
      return { diagnostics: [], status: 'execution-failed', errorMessage: message };
    }
  }

  isAvailable(): boolean {
    try {
      require.resolve('stylelint');
      return true;
    } catch {
      return false;
    }
  }
}
```

---

## 关键逻辑

- `check()`: 使用 `stylelint.lint({ code, codeFilename })` 直接检查代码文本，支持虚拟文档
- ruleId 加前缀 `stylelint:`，如 `stylelint:color-no-invalid-hex`
- `isAvailable()`: 通过 `require.resolve` 检测 stylelint 是否已安装
- 错误处理：模块未找到 → `tool-unavailable`，其他错误 → `execution-failed`

---

## 验收

- [ ] 文件创建完成
- [ ] `npm run compile` 通过
- [ ] `npm run lint` 通过