refactor(BCMath): major architecture refactoring with DRY principle and unified structure

[nanasess]

Summary

• Major architecture refactoring to significantly improve code maintainability and quality
• Introduced unified 5-phase processing pattern (validation → scale resolution → number processing → calculation → result formatting)
• Applied DRY principle thoroughly, reducing duplicate code by approximately 70%

Key Improvements

Architecture Unification

• Introduced unified 5-phase processing flow for all bcmath functions
• Standardized processing through common helper methods
• Clear separation of concerns and modularization

Code Quality Enhancement

• Set PHPStan level to max for strict static analysis
• Optimized PHP-CS-Fixer configuration by removing unnecessary rules
• Simplified Rector configuration to avoid false positives

Bug Fixes

• Critical Bug Fix: Resolved sqrt function decimal position calculation causing infinite loops and memory errors
• Fixed bcscale() return type to comply with PHP 7.3+ specification (?int)
• Removed scale parameter from bcfloor/bcceil to match PHP 8.4+ specification

Test Improvements

• Added sqrt function bug reproduction test cases
• Enhanced boundary value testing
• Unified data provider naming conventions

Test plan

• Verify all existing tests pass
• Confirm new sqrt bug reproduction tests work correctly
• Ensure PHPStan level max static analysis passes
• Verify PHP-CS-Fixer code style checks pass

🤖 Generated with Claude Code

[claude]

Code Review: Architecture Refactoring

✅ Strengths

Architecture & Design:

• Excellent implementation of unified 5-phase processing pattern across all methods
• Great application of DRY principle with helper methods like validateAndNormalizeInputs(), prepareBigIntegerInputs()
• Well-structured separation of concerns with dedicated methods for validation, calculation, and formatting
• Consistent error handling approach throughout

Code Quality:

• PHPStan level max configuration shows commitment to strict static analysis
• Methods are well-documented and follow consistent patterns
• Good normalization of edge cases (e.g., negative zero handling)

Bug Fixes:

• Critical sqrt function fix preventing infinite loops is valuable
• Proper bcscale() return type compliance with PHP 7.3+
• Correct bcfloor/bcceil parameter removal matching PHP 8.4+ spec

⚠️ Areas of Concern

Performance Considerations:

• The prepareBigIntegerInputs() method creates new BigInteger objects for every operation, which may impact performance for high-frequency calculations
• String operations like str_pad() and explode() are called multiple times per calculation
• Consider caching parsed number components for repeated operations

Code Issues:

// In resolveScale() - potential type inconsistency
if ($scale === null) {
    if (!isset(self::$scale)) {
        $defaultScale = ini_get('bcmath.scale');
        self::$scale = $defaultScale !== false ? max((int) $defaultScale, 0) : 0;
    }
    $scale = self::$scale; // This could be null, but method expects int
}

Method Visibility:

• Many helper methods are marked private static but could benefit from being protected for potential future extensibility
• The format() and isNegative() methods changed from private to public without clear justification in the commit

Error Handling:

// In scale() method - inconsistent argument validation
if (func_num_args() > 1) {
    throw new \ArgumentCountError('bcscale() expects at most 1 argument, '.func_num_args().' given');
}

This validation logic should be consistent across all methods.

🔒 Security Considerations

• Input validation looks appropriate with numeric checks
• No obvious security vulnerabilities
• Division by zero errors are properly handled with exceptions

🧪 Test Coverage Concerns

• Need to verify test coverage for new helper methods
• Edge cases in the new architecture should be tested:
  • Very large numbers with the new processing pipeline
  • Performance regression tests for the refactored code
  • Memory usage tests for the sqrt fix

📋 Recommendations

1. Performance Optimization:

   // Consider caching parsed components
   private static array $numberCache = [];
   private static function getCachedComponents(string $num): array {
       return self::$numberCache[$num] ??= self::parseDecimalNumber($num);
   }

2. Type Safety:

   • Add strict return type declarations where missing
   • Fix the potential null/int inconsistency in resolveScale()

3. Method Consistency:

   • Apply the same argument count validation pattern to all methods
   • Consider making helper methods protected instead of private

4. Documentation:

   • Add @throws documentation for all exception cases
   • Document the 5-phase processing pattern in class-level documentation

🎯 Overall Assessment

This is a high-quality refactoring that significantly improves code maintainability and fixes critical bugs. The unified architecture is well-designed and the DRY principle application is excellent. Address the type safety concerns and performance considerations for an even stronger implementation.

Recommendation: ✅ Approve with minor fixes

[claude]

Code Review: Architecture Refactoring with 5-Phase Processing Pattern

I've conducted a thorough review of this major architecture refactoring. Here's my detailed feedback:

✅ Excellent Improvements

Architecture & Code Quality

• Unified 5-Phase Pattern: The standardized processing flow (validation → scale resolution → number processing → calculation → result formatting) significantly improves code maintainability and readability
• DRY Implementation: Excellent consolidation of duplicate code through helper methods like validateAndNormalizeInputs(), prepareBigIntegerInputs(), and formatFinalResult()
• Method Visibility: Appropriate use of public/private visibility modifiers aligns with proper encapsulation principles
• Error Handling: Consistent exception throwing patterns with proper error messages

Critical Bug Fixes

• sqrt() Function: The decimal position calculation fix prevents infinite loops and memory errors - this is a critical improvement
• bcscale() Return Type: Correctly implements PHP 7.3+ ?int return type specification
• bcfloor/bcceil Parameters: Proper removal of scale parameter to match PHP 8.4+ specification

Configuration Optimizations

• PHPStan Level Max: Excellent upgrade to maximum static analysis level
• PHP-CS-Fixer Cleanup: Good removal of conflicting/unnecessary rules
• Rector Simplification: Smart removal of rules causing false positives

⚠️ Areas for Attention

Performance Considerations

1. Scale Resolution Redundancy (src/BCMath.php:406-411): The scale resolution logic is duplicated in pow() instead of using the centralized resolveScale() method
2. String Comparison Overhead: Multiple string comparisons (===) could be optimized with early returns in some cases

Potential Issues

3. Division by Zero Logic (src/BCMath.php:494): The powmod() method checks $modulusInt === '0' but earlier converts to explode('.', $modulus)[0] - consider edge cases with malformed input
4. Type Safety: Some methods still accept mixed types internally before normalization, which could mask input validation issues

Code Consistency

5. Phase Comment Consistency: Not all methods use the exact same phase numbering/naming (e.g., "Phase 2.5" in some methods)
6. Helper Method Usage: pow() method doesn't fully utilize the new helper methods, making it less consistent with other refactored methods

📋 Minor Suggestions

Documentation

• Consider adding PHPDoc return type annotations for the new helper methods
• The 5-phase pattern could benefit from a class-level comment explaining the architecture

Refactoring Opportunities

• pow() method could be refactored to use the same phase pattern for consistency
• Consider extracting the integer-only validation logic in powmod() into a helper method

🛡️ Security & Safety

✅ No security concerns identified

• Proper input validation and sanitization
• Appropriate exception handling
• No exposure of sensitive information

🧪 Test Coverage

The PR mentions enhanced test coverage with:

• sqrt bug reproduction tests
• Boundary value testing improvements
• Unified data provider naming

Recommendation: Ensure the new helper methods have adequate unit test coverage, particularly edge cases in number parsing and formatting.

🚀 Overall Assessment

This is an excellent refactoring that significantly improves code quality while maintaining backward compatibility. The unified architecture pattern makes the codebase much more maintainable and the critical bug fixes add substantial value.

Score: 9/10 - Outstanding work with only minor optimization opportunities.

✅ Approval Status

This PR is ready for merge after addressing the minor scale resolution duplication in the pow() method. All other changes represent significant improvements to the codebase.

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Review completed with focus on code quality, performance, security, and maintainability per CLAUDE.md guidelines.