Code Organization

Code Organization Skill

This skill ensures proper code organization following the core principle: Directory X contains ONLY class type X.

When to Use This Skill

Activate this skill when:

• Creating new classes
• Refactoring existing code
• Moving classes between directories
• Code review feedback about organization
• Renaming classes or methods

Core Principle

Directory X should contain ONLY class type X

Examples:

• Converter/ → Contains ONLY converters
• Transformer/ → Contains ONLY transformers
• Validator/ → Contains ONLY validators
• Builder/ → Contains ONLY builders
• Fixer/ → Contains ONLY fixers
• Cleaner/ → Contains ONLY cleaners
• Factory/ → Contains ONLY factories
• Resolver/ → Contains ONLY resolvers

Quick Reference: Where Does It Belong?

Organization Checklist

1. Class Location

✅ CORRECT:

// File: src/Shared/Infrastructure/Converter/UlidTypeConverter.php
namespace App\Shared\Infrastructure\Converter;

final class UlidTypeConverter  // IS a Converter
{
    public function toUlid(...): Ulid { }
    public function fromBinary(...): Ulid { }
}

❌ WRONG:

// File: src/Shared/Infrastructure/Transformer/UlidTypeConverter.php
namespace App\Shared\Infrastructure\Transformer;

final class UlidTypeConverter  // IS a Converter, NOT a Transformer!
{
    // This belongs in Converter/, not Transformer/
}

2. Class Name Consistency

✅ CORRECT:

• UlidValidator → validates ULIDs
• UlidTransformer → transforms for Doctrine
• UlidTypeConverter → converts between types
• CustomerUpdateScalarResolver → resolves scalar values

❌ WRONG:

• UlidHelper → Too vague
• UlidConverter → Not specific enough
• UlidUtils → Extract to specific classes

3. Namespace Consistency

Namespace MUST match directory structure:

✅ CORRECT:

// File: src/Shared/Infrastructure/Validator/UlidValidator.php
namespace App\Shared\Infrastructure\Validator;

❌ WRONG:

// File: src/Shared/Infrastructure/Validator/UlidValidator.php
namespace App\Shared\Infrastructure\Transformer;  // Wrong namespace!

Refactoring Workflow

Step 1: Identify What the Class Does

Ask yourself:

• What is the PRIMARY responsibility of this class?
• Does it convert? → Converter/
• Does it transform? → Transformer/
• Does it validate? → Validator/
• Does it build? → Builder/
• Does it fix? → Fixer/
• Does it clean? → Cleaner/
• Does it resolve? → Resolver/

Step 2: Check the Directory

Current location matches responsibility?

• ✅ YES → Class is correctly placed
• ❌ NO → Move to appropriate directory

Step 3: Update All References

1. Move the file:

   mv src/Path/OldDir/Class.php src/Path/NewDir/Class.php
   

2. Update namespace in the file:

   namespace App\Path\NewDir;
   

3. Update all imports:

   # Find all files using this class
   grep -r "use.*OldDir\\ClassName" src/ tests/
   
   # Update them (or use IDE refactoring)
   sed -i 's|OldDir\\ClassName|NewDir\\ClassName|g' affected_files
   

4. Run quality checks:

   make phpcsfixer
   make psalm
   make unit-tests
   

Step 4: Verify Consistency

Check that:

• Class is in correct directory
• Namespace matches directory
• Class name matches functionality
• Variable names are specific
• Parameter names are accurate
• All tests pass

Essential Examples

Example 1: UlidValidator

Before:

// ❌ src/Shared/Infrastructure/Transformer/UlidValidator.php
namespace App\Shared\Infrastructure\Transformer;

final class UlidValidator { }  // It's a VALIDATOR, not a Transformer!

After:

// ✅ src/Shared/Infrastructure/Validator/UlidValidator.php
namespace App\Shared\Infrastructure\Validator;

final class UlidValidator { }

Example 2: CustomerUpdateScalarResolver

Before:

// ❌ src/Core/Customer/Application/Factory/CustomerUpdateScalarResolver.php
namespace App\Core\Customer\Application\Factory;

final class CustomerUpdateScalarResolver  // It's a RESOLVER, not a FACTORY!
{
    public function resolveScalarValue(...) { }
}

After:

// ✅ src/Core/Customer/Application/Resolver/CustomerUpdateScalarResolver.php
namespace App\Core\Customer\Application\Resolver;

final class CustomerUpdateScalarResolver
{
    public function resolveScalarValue(...) { }
}

Variable and Parameter Naming

Variable Names

✅ CORRECT (Specific):

private UlidTypeConverter $typeConverter;
private CustomerUpdateScalarResolver $scalarResolver;

❌ WRONG (Vague):

private UlidTypeConverter $converter;      // Converter of what?
private CustomerUpdateScalarResolver $resolver;  // Resolver of what?

Parameter Names

✅ CORRECT (Accurate):

public function toPhpValue(mixed $value): Ulid  // Accepts mixed
public function fromBinary(mixed $value): Ulid  // Accepts mixed despite name

❌ WRONG (Misleading):

public function fromBinary(mixed $binary): Ulid  // Name suggests only binary

Common Mistakes to Avoid

1. Don't create "Helper" or "Util" classes

   • These are code smells
   • Extract specific responsibilities into properly named classes

2. Don't put multiple class types in one directory

   • Converters don't belong in Transformer/
   • Validators don't belong in Converter/

3. Don't use vague variable names

   • $converter → $typeConverter (be specific)
   • $data → $customerData (be descriptive)

4. Don't mismatch parameter names with types

   • If parameter accepts mixed, don't name it after one type

PHP Best Practices

Use Constructor Property Promotion

✅ CORRECT:

final readonly class CustomerUpdateFactory
{
    public function __construct(
        private CustomerRelationTransformerInterface $relationResolver,
        private CustomerUpdateScalarResolver $scalarResolver,
    ) {
    }
}

Always Inject All Dependencies

✅ CORRECT (All dependencies injected):

public function __construct(
    private readonly IriReferenceMediaTypeTransformerInterface $mediaTypeTransformer
) {
}

❌ WRONG (Default instantiation):

public function __construct(
    ?IriReferenceMediaTypeTransformerInterface $mediaTypeTransformer = null
) {
    $this->mediaTypeTransformer = $mediaTypeTransformer
        ?? new IriReferenceMediaTypeTransformer();  // ❌ Direct instantiation!
}

For complete PHP best practices, see php-best-practices.md.

Pre-Commit Checklist

Before committing code organization changes:

# 1. Check code style
make phpcsfixer

# 2. Check static analysis
make psalm

# 3. Run unit tests
make unit-tests

# 4. Verify consistency
grep -r "^namespace" src/ --include="*.php" | head -10

Success Criteria

✅ Directory contains only the type of class it's named for ✅ Class name accurately describes functionality ✅ Namespace matches directory structure ✅ Variable names are specific and clear ✅ Parameter names match their actual types ✅ All tests pass ✅ No Psalm errors ✅ Code style compliant

Related Skills

• quality-standards: Maintains code quality metrics
• ci-workflow: Runs comprehensive checks
• code-review: Handles PR feedback about organization
• testing-workflow: Ensures proper test coverage

Additional Resources

• php-best-practices.md - Complete PHP best practices guide
• examples/refactoring-examples.md - Detailed before/after examples
• reference/directory-structure.md - Layer-by-layer breakdown
• reference/common-patterns.md - Pattern catalog
• reference/troubleshooting.md - Troubleshooting guide for common issues
• ../.claude/skills/SKILL-DECISION-GUIDE.md - When to use which skill