# Implementation Plan: The Polyglot Bridge

## Overview

This implementation plan breaks down the Polyglot Bridge project into discrete, incremental coding tasks. Each task builds on previous work, starting with project setup, then core Rust functionality, PyO3 bindings, testing, and finally benchmarking. The plan emphasizes early validation through testing and ensures all components are properly integrated.

## Tasks

- [x] 1. Project setup and structure
  - Create Cargo.toml with edition 2024, rust-version 1.93, and cdylib crate type
  - Create pyproject.toml with maturin build configuration
  - Set up directory structure: src/, tests/, benches/, python/
  - Initialize error types module (src/error.rs) with BridgeError enum using thiserror
  - _Requirements: 6.5, 8.4, 8.5_

- [x] 2. Implement core mathematical operations
  - [x] 2.1 Implement sum_of_squares function in src/core/math.rs
    - Accept &[f64] slice parameter
    - Use iterator chain with map and sum
    - Return Result<f64, BridgeError>
    - Handle empty input and overflow cases
    - _Requirements: 2.1, 2.5, 8.2, 8.6_
  
  - [x] 2.2 Write property test for sum_of_squares
    - **Property 6: Algorithmic Equivalence**
    - **Validates: Requirements 5.1**
    - Use proptest to generate random f64 vectors
    - Compare Rust implementation with pure mathematical formula
    - Test with 100+ iterations
  
  - [x] 2.3 Implement matrix_multiply function in src/core/math.rs
    - Use iterator-based approach (no manual indexing)
    - Validate matrix dimensions
    - Return Result<Vec<Vec<f64>>, BridgeError>
    - _Requirements: 2.1, 2.3, 8.6_
  
  - [x] 2.4 Write unit tests for matrix_multiply
    - Test known matrix multiplication examples
    - Test dimension mismatch error
    - Test empty matrix error
    - _Requirements: 2.1, 8.3_

- [x] 3. Implement parallel data processing
  - [x] 3.1 Implement parallel_transform in src/core/parallel.rs
    - Use rayon's par_iter for parallel processing
    - Accept &[f64] and factor parameter
    - Return Result<Vec<f64>, BridgeError>
    - _Requirements: 2.2, 2.4_
  
  - [x] 3.2 Write property test for parallel_transform
    - **Property 6: Algorithmic Equivalence**
    - **Validates: Requirements 5.1**
    - Compare parallel and sequential implementations
    - Verify results are identical

- [x] 4. Checkpoint - Ensure core Rust tests pass
  - Run `cargo test` and verify all tests pass
  - Run `cargo clippy` and fix any warnings
  - Ensure all tests pass, ask the user if questions arise.

- [x] 5. Implement PyO3 bindings layer
  - [x] 5.1 Create Python module definition in src/lib.rs
    - Define #[pymodule] function
    - Export all public functions with #[pyfunction]
    - Add comprehensive docstrings with Args, Returns, Raises, Example sections
    - _Requirements: 1.1, 7.1, 7.2_
  
  - [x] 5.2 Implement PyO3 wrapper for sum_of_squares
    - Accept Vec<f64> from Python
    - Convert BridgeError to PyErr using From trait
    - Return PyResult<f64>
    - _Requirements: 1.2, 3.1, 4.1, 4.2, 4.3_
  
  - [x] 5.3 Implement PyO3 wrapper for matrix_multiply
    - Accept Vec<Vec<f64>> from Python
    - Handle type conversion and error propagation
    - Return PyResult<Vec<Vec<f64>>>
    - _Requirements: 1.2, 3.1, 4.3, 4.5_
  
  - [x] 5.4 Implement PyO3 wrapper for parallel_transform
    - Accept Vec<f64> and f64 factor from Python
    - Handle error conversion
    - Return PyResult<Vec<f64>>
    - _Requirements: 1.2, 3.1, 4.2, 4.3_

- [x] 6. Python integration testing
  - [x] 6.1 Write Python test for module import
    - Test that polyglot_bridge module can be imported
    - Verify all expected functions are accessible
    - **Validates: Requirements 1.1**
  
  - [x] 6.2 Write property test for type conversion round trip
    - **Property 1: Type Conversion Round Trip**
    - **Validates: Requirements 4.1, 4.2, 4.3, 4.4, 4.5**
    - Use hypothesis to generate random Python values
    - Test int, float, str, list conversions
  
  - [x] 6.3 Write property test for function call type safety
    - **Property 2: Function Call Type Safety**
    - **Validates: Requirements 1.2**
    - Use hypothesis to generate valid inputs
    - Verify return types are correct Python types
  
  - [x] 6.4 Write property test for error conversion
    - **Property 3: Error Conversion Completeness**
    - **Validates: Requirements 3.1, 3.2, 3.3, 3.4**
    - Trigger various error conditions
    - Verify appropriate Python exceptions are raised with messages
  
  - [x] 6.5 Write property test for invalid type rejection
    - **Property 4: Invalid Type Rejection**
    - **Validates: Requirements 3.3, 4.6**
    - Pass invalid types to functions
    - Verify TypeError is raised with descriptive messages
  
  - [x] 6.6 Write test for panic safety
    - **Property 5: Panic Safety**
    - **Validates: Requirements 3.5**
    - Create scenarios that could cause panics
    - Verify Python interpreter doesn't crash
  
  - [x] 6.7 Write unit tests for Python API ergonomics
    - Test that help() displays proper documentation
    - Verify docstrings are present
    - Test keyword arguments work correctly
    - _Requirements: 1.3, 7.2_

- [x] 7. Checkpoint - Ensure Python integration tests pass
  - Build with `maturin develop`
  - Run Python tests with `pytest tests/test_python.py`
  - Ensure all tests pass, ask the user if questions arise.

- [x] 8. Implement performance benchmarks
  - [x] 8.1 Create Rust benchmarks using Criterion
    - Benchmark sum_of_squares with various input sizes
    - Benchmark matrix_multiply with different matrix dimensions
    - Benchmark parallel_transform with different data sizes
    - _Requirements: 5.2, 5.4_
  
  - [x] 8.2 Create Python benchmark script
    - Implement pure Python versions of all functions
    - Measure execution time for both Rust and Python implementations
    - Calculate and report speedup ratios
    - Test across multiple input sizes (100, 1000, 10000 elements)
    - _Requirements: 5.1, 5.2, 5.3, 5.4, 5.6_
  
  - [x] 8.3 Write benchmark comparison tests
    - **Property 6: Algorithmic Equivalence**
    - **Validates: Requirements 5.1**
    - Verify Rust and Python implementations produce equivalent results
    - Use floating-point tolerance for comparisons

- [x] 9. Documentation and type stubs
  - [x] 9.1 Generate Python type stub file (.pyi)
    - Create polyglot_bridge.pyi with type hints
    - Include all function signatures
    - _Requirements: 1.4, 7.1_
  
  - [x] 9.2 Create README with quickstart guide
    - Installation instructions
    - Basic usage examples
    - Performance characteristics
    - _Requirements: 7.3, 7.4, 7.5_
  
  - [x] 9.3 Add inline code examples to docstrings
    - Include practical examples in each function's docstring
    - _Requirements: 7.3_

- [x] 10. Final integration and validation
  - [x] 10.1 Build release wheel package
    - Run `maturin build --release`
    - Verify wheel is created in dist/
    - _Requirements: 6.1, 6.2_
  
  - [x] 10.2 Test installation from wheel
    - Install wheel with pip
    - Run all tests against installed package
    - _Requirements: 6.3_
  
  - [x] 10.3 Run full test suite
    - Run `cargo test` for Rust tests
    - Run `cargo clippy` and ensure no warnings
    - Run `pytest` for Python tests
    - Run benchmarks and verify performance gains
    - _Requirements: 8.1, 8.3_

- [x] 11. Final checkpoint - Complete validation
  - Ensure all tests pass (Rust and Python)
  - Verify benchmarks show expected performance improvements
  - Confirm documentation is complete
  - Ensure all tests pass, ask the user if questions arise.

## Notes

- All tasks are required for comprehensive implementation
- Each task references specific requirements for traceability
- Checkpoints ensure incremental validation at key milestones
- Property tests validate universal correctness properties with 100+ iterations
- Unit tests validate specific examples and edge cases
- The implementation follows Rust Edition 2024 and targets Rust 1.93+
- All code should pass `cargo clippy` without warnings
