{
  "ruleId": "C020",
  "name": "Unused Imports",
  "description": "Không import các module hoặc symbol không sử dụng",
  "category": "code-quality",
  "severity": "warning",
  "languages": ["typescript", "javascript"],
  "version": "1.0.0",
  "status": "stable",
  "tags": ["imports", "cleanup", "unused-code"],
  "config": {
    "checkDefaultImports": true,
    "checkNamedImports": true,
    "checkNamespaceImports": true,
    "ignoreTypeImports": false,
    "allowedUnusedPatterns": [
      "^_"
    ]
  },
  "examples": {
    "violations": [
      {
        "language": "typescript",
        "code": "import { Order } from './models/Order';\n\n// Order is never used",
        "reason": "Imported 'Order' but never used in the code"
      },
      {
        "language": "typescript",
        "code": "import fs from 'fs';\nimport path from 'path';\n\n// Only path is used\nconsole.log(path.join('a', 'b'));",
        "reason": "Imported 'fs' but never used"
      },
      {
        "language": "typescript",
        "code": "import * as utils from './utils';\n\n// utils namespace is never used",
        "reason": "Imported namespace 'utils' but never used"
      }
    ],
    "valid": [
      {
        "language": "typescript",
        "code": "import { User } from './models/User';\n\nconst user = new User();",
        "reason": "User is imported and used"
      },
      {
        "language": "typescript",
        "code": "import type { Order } from './types';\n\nconst order: Order = { id: 1 };",
        "reason": "Type import is used in type annotation"
      },
      {
        "language": "typescript",
        "code": "import { _debugHelper } from './utils';\n\n// Allowed: starts with underscore",
        "reason": "Import starting with _ is allowed as intentionally unused"
      }
    ]
  },
  "fixes": {
    "autoFixable": true,
    "suggestions": [
      "Remove unused imports to keep code clean",
      "Use IDE auto-import features to avoid manual imports",
      "Prefix intentionally unused imports with underscore (_)"
    ]
  }
}