"""Testing helper functions

Warning: current status experimental, mostly copy paste

Warning: these functions will be changed without warning as the need
during refactoring arises.

The first group of functions provide consistency checks

"""

import os
import sys
from packaging.version import Version, parse

import numpy as np
from numpy.testing import assert_allclose, assert_

import pandas as pd


class PytestTester:
    def __init__(self, package_path=None):
        f = sys._getframe(1)
        if package_path is None:
            package_path = f.f_locals.get('__file__', None)
            if package_path is None:
                raise ValueError('Unable to determine path')
        self.package_path = os.path.dirname(package_path)
        self.package_name = f.f_locals.get('__name__', None)

    def __call__(self, extra_args=None, exit=False):
        try:
            import pytest
            if not parse(pytest.__version__) >= Version('3.0'):
                raise ImportError
            if extra_args is None:
                extra_args = ['--tb=short', '--disable-pytest-warnings']
            cmd = [self.package_path] + extra_args
            print('Running pytest ' + ' '.join(cmd))
            status = pytest.main(cmd)
            if exit:
                sys.exit(status)
        except ImportError:
            raise ImportError('pytest>=3 required to run the test')


def check_ttest_tvalues(results):
    # test that t_test has same results a params, bse, tvalues, ...
    res = results
    mat = np.eye(len(res.params))
    tt = res.t_test(mat)

    assert_allclose(tt.effect, res.params, rtol=1e-12)
    # TODO: tt.sd and tt.tvalue are 2d also for single regressor, squeeze
    assert_allclose(np.squeeze(tt.sd), res.bse, rtol=1e-10)
    assert_allclose(np.squeeze(tt.tvalue), res.tvalues, rtol=1e-12)
    assert_allclose(tt.pvalue, res.pvalues, rtol=5e-10)
    assert_allclose(tt.conf_int(), res.conf_int(), rtol=1e-10)

    # test params table frame returned by t_test
    table_res = np.column_stack((res.params, res.bse, res.tvalues,
                                 res.pvalues, res.conf_int()))
    table2 = tt.summary_frame().values
    assert_allclose(table2, table_res, rtol=1e-12)

    # TODO: move this to test_attributes ?
    assert_(hasattr(res, 'use_t'))

    tt = res.t_test(mat[0])
    tt.summary()   # smoke test for #1323
    assert_allclose(tt.pvalue, res.pvalues[0], rtol=5e-10)
    # TODO: Adapt more of test_generic_methods.test_ttest_values here?


def check_ftest_pvalues(results):
    """
    Check that the outputs of `res.wald_test` produces pvalues that
    match res.pvalues.

    Check that the string representations of `res.summary()` and (possibly)
    `res.summary2()` correctly label either the t or z-statistic.

    Parameters
    ----------
    results : Results

    Raises
    ------
    AssertionError
    """
    res = results
    use_t = res.use_t
    k_vars = len(res.params)
    # check default use_t
    pvals = [res.wald_test(np.eye(k_vars)[k], use_f=use_t, scalar=True).pvalue
             for k in range(k_vars)]
    assert_allclose(pvals, res.pvalues, rtol=5e-10, atol=1e-25)

    # automatic use_f based on results class use_t
    pvals = [res.wald_test(np.eye(k_vars)[k], scalar=True).pvalue
             for k in range(k_vars)]
    assert_allclose(pvals, res.pvalues, rtol=5e-10, atol=1e-25)

    # TODO: Separate these out into summary/summary2 tests?
    # label for pvalues in summary
    string_use_t = 'P>|z|' if use_t is False else 'P>|t|'
    summ = str(res.summary())
    assert_(string_use_t in summ)

    # try except for models that do not have summary2
    try:
        summ2 = str(res.summary2())
    except AttributeError:
        pass
    else:
        assert_(string_use_t in summ2)


def check_fitted(results):
    import pytest

    # ignore wrapper for isinstance check
    from statsmodels.genmod.generalized_linear_model import GLMResults
    from statsmodels.discrete.discrete_model import DiscreteResults

    # possibly unwrap -- GEE has no wrapper
    results = getattr(results, '_results', results)

    if isinstance(results, (GLMResults, DiscreteResults)):
        pytest.skip('Not supported for {0}'.format(type(results)))

    res = results
    fitted = res.fittedvalues
    assert_allclose(res.model.endog - fitted, res.resid, rtol=1e-12)
    assert_allclose(fitted, res.predict(), rtol=1e-12)


def check_predict_types(results):
    """
    Check that the `predict` method of the given results object produces the
    correct output type.

    Parameters
    ----------
    results : Results

    Raises
    ------
    AssertionError
    """
    res = results
    # squeeze to make 1d for single regressor test case
    p_exog = np.squeeze(np.asarray(res.model.exog[:2]))

    # ignore wrapper for isinstance check
    from statsmodels.genmod.generalized_linear_model import GLMResults
    from statsmodels.discrete.discrete_model import DiscreteResults
    from statsmodels.compat.pandas import assert_frame_equal, assert_series_equal

    # possibly unwrap -- GEE has no wrapper
    results = getattr(results, '_results', results)

    if isinstance(results, (GLMResults, DiscreteResults)):
        # SMOKE test only  TODO: mark this somehow
        res.predict(p_exog)
        res.predict(p_exog.tolist())
        res.predict(p_exog[0].tolist())
    else:
        fitted = res.fittedvalues[:2]
        assert_allclose(fitted, res.predict(p_exog), rtol=1e-12)
        # this needs reshape to column-vector:
        assert_allclose(fitted, res.predict(np.squeeze(p_exog).tolist()),
                        rtol=1e-12)
        # only one prediction:
        assert_allclose(fitted[:1], res.predict(p_exog[0].tolist()),
                        rtol=1e-12)
        assert_allclose(fitted[:1], res.predict(p_exog[0]),
                        rtol=1e-12)

        # Check that pandas wrapping works as expected
        exog_index = range(len(p_exog))
        predicted = res.predict(p_exog)

        cls = pd.Series if p_exog.ndim == 1 else pd.DataFrame
        predicted_pandas = res.predict(cls(p_exog, index=exog_index))

        # predicted.ndim may not match p_exog.ndim because it may be squeezed
        #  if p_exog has only one column
        cls = pd.Series if predicted.ndim == 1 else pd.DataFrame
        predicted_expected = cls(predicted, index=exog_index)
        if isinstance(predicted_expected, pd.Series):
            assert_series_equal(predicted_expected, predicted_pandas)
        else:
            assert_frame_equal(predicted_expected, predicted_pandas)
