Refactor Assistant

Guide safe, incremental code refactoring.

Identify Refactoring Type

First, determine what kind of refactoring is needed:

Code smells? -> See "Smell-Based Refactoring" below Adding feature? -> See "Preparatory Refactoring" below Performance issue? -> See "Performance Refactoring" below Improving design? -> See "Design Pattern Refactoring" below

Smell-Based Refactoring

Long Function

Symptoms: Function > 30 lines, multiple responsibilities Solution: Extract Method

# Before
def process_order(order):
    # validate (10 lines)
    # calculate (15 lines)  
    # save (10 lines)

# After
def process_order(order):
    validate_order(order)
    total = calculate_total(order)
    save_order(order, total)

Duplicate Code

Symptoms: Same logic in multiple places Solution: Extract and reuse

Long Parameter List

Symptoms: Function has > 4 parameters Solution: Introduce Parameter Object

# Before
def create_user(name, email, age, city, country, phone):
    ...

# After
def create_user(user_data: UserData):
    ...

Feature Envy

Symptoms: Method uses another class's data extensively Solution: Move Method to that class

Preparatory Refactoring

Before adding a feature, make the change easy:

1. Identify where new code will go
2. Refactor existing code to create clean insertion point
3. Add the new feature
4. Clean up if needed

Performance Refactoring

1. Measure first - Profile before optimizing
2. Find bottleneck - Focus on hot paths
3. Apply fix - One change at a time
4. Measure again - Verify improvement

Common fixes:

• Cache repeated calculations
• Batch database queries
• Use appropriate data structures
• Lazy load expensive resources

Design Pattern Refactoring

See patterns/ for detailed guides:

• strategy.md - Replace conditionals with polymorphism
• factory.md - Centralize object creation
• decorator.md - Add behavior without modification

Safety Rules

1. Run tests before refactoring
2. Make small, incremental changes
3. Run tests after each change
4. Commit working states frequently