#!/usr/bin/env python
"""
This will generate an API file for formula in dir/statsmodels/formula/api.py

It first builds statsmodels in place, then generates the file. It's to be run
by developers to add files to the formula API without having to maintain this
by hand.

usage

generate_formula_api /home/skipper/statsmodels/statsmodels/
"""

import os
import sys


def iter_subclasses(cls, _seen=None, template_classes=[]):
    """
    Generator to iterate over all the subclasses of Model. Based on

    http://code.activestate.com/recipes/576949-find-all-subclasses-of-a-given-class/

    Yields class
    """
    if not isinstance(cls, type):
        raise TypeError(
            "itersubclasses must be called with "
            "new-style classes, not %.100r" % cls
        )
    if _seen is None:
        _seen = set()
    try:
        subs = cls.__subclasses__()
    except TypeError:  # fails only when cls is type
        subs = cls.__subclasses__(cls)
    for sub in subs:
        if sub not in _seen and sub.__name__ not in template_classes:
            _seen.add(sub)
            # we do not want to yield the templates, but we do want to
            # recurse on them
            yield sub
        for sub in iter_subclasses(sub, _seen, template_classes):
            yield sub


def write_formula_api(directory):
    template_classes = [
        "DiscreteModel",
        "BinaryModel",
        "MultinomialModel",
        "OrderedModel",
        "CountModel",
        "LikelihoodModel",
        "GenericLikelihoodModel",
        "TimeSeriesModel",
        # this class should really be deleted
        "ARIMAProcess",
        # these need some more work, so do not expose them
        "ARIMA",
        "VAR",
        "SVAR",
        "AR",
        "NBin",
        "NbReg",
        "ARMA",
    ]

    path = os.path.join(directory, "statsmodels", "formula", "api.py")
    fout = open(path, "w")
    for model in iter_subclasses(Model, template_classes=template_classes):
        print("Generating API for %s" % model.__name__)
        fout.write(
            "from " + model.__module__ + " import " + model.__name__ + "\n"
        )
        fout.write(
            model.__name__.lower() + " = " + model.__name__ + ".from_formula\n"
        )
    fout.close()


if __name__ == "__main__":
    import statsmodels.api as sm

    print(
        "Generating formula API for statsmodels version %s"
        % sm.version.full_version
    )
    directory = sys.argv[1]
    cur_dir = os.path.dirname(__file__)
    os.chdir(directory)
    # it needs to be installed to walk the whole subclass chain?
    from statsmodels.base.model import Model

    write_formula_api(directory)
