Developer Guide
===============

This page describes how to contribute to g4hunterpy3, including setting up a
development environment, running tests, writing code, and submitting changes.


.. contents:: On this page
   :local:
   :depth: 2


Setting Up a Development Environment
-------------------------------------

1. **Fork and clone** the repository:

   .. code-block:: bash

       git clone https://github.com/<your-username>/g4hunterpy3.git
       cd g4hunterpy3

2. **Create a conda environment** for development:

   .. code-block:: bash

       conda create -n g4hunter-dev python=3.11 -y
       conda activate g4hunter-dev

3. **Install the package in editable mode** with test dependencies:

   .. code-block:: bash

       pip install -e ".[test]"

4. **Verify** everything is working:

   .. code-block:: bash

       pytest


Project Layout
--------------

::

    g4hunterpy3/
    ├── g4hunterpy3/            # main package
    │   ├── __init__.py
    │   ├── core.py             # scoring algorithms
    │   ├── plotting.py         # visualization functions
    │   ├── scripts/
    │   │   └── cli.py          # command-line interface
    │   └── tests/
    │       ├── test_core.py
    │       ├── test_plotting.py
    │       └── test_g4hunterpy3.py
    ├── docs/                   # Sphinx documentation
    ├── pyproject.toml          # build config & dependencies
    └── setup.cfg               # flake8 / coverage settings


Development Workflow
--------------------

1. **Create a feature branch** from ``main``:

   .. code-block:: bash

       git checkout -b feature/my-new-feature

2. Make your changes, keeping commits small and focused.

3. **Run the test suite** before committing:

   .. code-block:: bash

       pytest

4. Push your branch and **open a Pull Request** against ``main``.


Running Tests
-------------

The test suite uses `pytest <https://docs.pytest.org/>`_:

.. code-block:: bash

    # run all tests
    pytest

    # run with verbose output
    pytest -v

    # run a specific test file
    pytest g4hunterpy3/tests/test_core.py

    # run a single test by name
    pytest -k "test_base_scores"

    # run with coverage report
    pytest --cov=g4hunterpy3


Writing Code
------------

Style guidelines
^^^^^^^^^^^^^^^^

- Follow `PEP 8 <https://peps.python.org/pep-0008/>`_ for Python style.
- Maximum line length is **119 characters** (configured in ``setup.cfg``).
- Use **NumPy-style docstrings** for all public functions and classes.

Docstring example
^^^^^^^^^^^^^^^^^

.. code-block:: python

    def my_function(seq: str, window_size: int = 25) -> np.ndarray:
        """Short one-line summary of the function.

        Longer description if needed, explaining the algorithm or
        important behavior.

        Parameters
        ----------
        seq : str
            Input DNA sequence.
        window_size : int, default=25
            Sliding window length in bases.

        Returns
        -------
        numpy.ndarray
            Description of the return value.

        Raises
        ------
        ValueError
            If window_size is invalid.
        """

Type hints
^^^^^^^^^^

- Add type hints to function signatures.
- The codebase uses ``from __future__ import annotations`` for forward
  references.


Writing Tests
-------------

- Place test files in ``g4hunterpy3/tests/``.
- Name test files ``test_<module>.py`` and test functions ``test_<thing>()``.
- Test both normal behavior and edge cases.
- Keep tests fast and independent of external resources.

Example:

.. code-block:: python

    import numpy as np
    from g4hunterpy3.core import base_scores

    def test_base_scores_g_run():
        """G-runs should produce positive scores capped at 4."""
        scores = base_scores("GGGGG")
        assert (scores == 4).all()

    def test_base_scores_mixed():
        """Non-G/C bases should score 0."""
        scores = base_scores("ATATA")
        assert (scores == 0).all()


Building the Documentation
---------------------------

The docs use `Sphinx <https://www.sphinx-doc.org/>`_ with the
``pydata-sphinx-theme``. To build locally:

.. code-block:: bash

    # install doc dependencies
    pip install -r docs/requirements.txt

    # build HTML docs
    cd docs
    make html

    # open in browser
    open _build/html/index.html    # macOS
    xdg-open _build/html/index.html  # Linux

When adding new public functions or modules, make sure they appear in
``docs/api.rst`` so they are included in the API reference.


Pull Request Checklist
----------------------

Before submitting a PR, please verify:

- [ ] All existing tests pass (``pytest``).
- [ ] New functionality includes tests.
- [ ] Public functions have NumPy-style docstrings.
- [ ] Code follows the style guidelines (PEP 8, 119-char line limit).
- [ ] Documentation builds without warnings (``make html`` in ``docs/``).
- [ ] Commit messages are clear and descriptive.


Reporting Issues
----------------

If you find a bug or have a feature request, please
`open an issue <https://github.com/holehouse-lab/g4hunterpy3/issues>`_
on GitHub. Include:

- A description of the problem or desired feature.
- Steps to reproduce (for bugs).
- Your Python version and OS.
- The output of ``python -c "import g4hunterpy3; print(g4hunterpy3.__version__)"``.