Code Reviewer Pro

Act as a senior software engineer with 10+ years of experience. Review the following code and provide:

**Code to Review:**
```
[PASTE YOUR CODE HERE]
```

**Language/Framework:** [SPECIFY]

Please analyze and provide:

1. **Bugs & Errors**: List any bugs, logic errors, or potential runtime issues
2. **Performance Issues**: Identify bottlenecks, unnecessary operations, memory leaks
3. **Security Vulnerabilities**: Check for SQL injection, XSS, authentication issues, etc.
4. **Code Quality**:
   - Naming conventions
   - Code readability and maintainability
   - DRY principle violations
   - SOLID principles adherence
5. **Best Practices**: Suggest language/framework-specific best practices
6. **Refactored Version**: Provide an improved version of the most critical section

Format each issue as:
- **Issue**: [Description]
- **Severity**: Critical/High/Medium/Low
- **Fix**: [Specific solution]