from collections import defaultdict
from functools import partial

import numpy as np
import pytest
import scipy.sparse as sp

from sklearn.utils._testing import assert_array_equal
from sklearn.utils._testing import assert_almost_equal
from sklearn.utils._testing import assert_array_almost_equal
from sklearn.utils._testing import assert_raise_message

from sklearn.datasets import make_classification
from sklearn.datasets import make_multilabel_classification
from sklearn.datasets import make_hastie_10_2
from sklearn.datasets import make_regression
from sklearn.datasets import make_blobs
from sklearn.datasets import make_friedman1
from sklearn.datasets import make_friedman2
from sklearn.datasets import make_friedman3
from sklearn.datasets import make_low_rank_matrix
from sklearn.datasets import make_moons
from sklearn.datasets import make_circles
from sklearn.datasets import make_sparse_coded_signal
from sklearn.datasets import make_sparse_uncorrelated
from sklearn.datasets import make_spd_matrix
from sklearn.datasets import make_swiss_roll
from sklearn.datasets import make_s_curve
from sklearn.datasets import make_biclusters
from sklearn.datasets import make_checkerboard

from sklearn.utils.validation import assert_all_finite


def test_make_classification():
    weights = [0.1, 0.25]
    X, y = make_classification(n_samples=100, n_features=20, n_informative=5,
                               n_redundant=1, n_repeated=1, n_classes=3,
                               n_clusters_per_class=1, hypercube=False,
                               shift=None, scale=None, weights=weights,
                               random_state=0)

    assert weights == [0.1, 0.25]
    assert X.shape == (100, 20), "X shape mismatch"
    assert y.shape == (100,), "y shape mismatch"
    assert np.unique(y).shape == (3,), "Unexpected number of classes"
    assert sum(y == 0) == 10, "Unexpected number of samples in class #0"
    assert sum(y == 1) == 25, "Unexpected number of samples in class #1"
    assert sum(y == 2) == 65, "Unexpected number of samples in class #2"

    # Test for n_features > 30
    X, y = make_classification(n_samples=2000, n_features=31, n_informative=31,
                               n_redundant=0, n_repeated=0, hypercube=True,
                               scale=0.5, random_state=0)

    assert X.shape == (2000, 31), "X shape mismatch"
    assert y.shape == (2000,), "y shape mismatch"
    assert (np.unique(X.view([('', X.dtype)]*X.shape[1])).view(X.dtype)
            .reshape(-1, X.shape[1]).shape[0] == 2000), (
                "Unexpected number of unique rows")


def test_make_classification_informative_features():
    """Test the construction of informative features in make_classification

    Also tests `n_clusters_per_class`, `n_classes`, `hypercube` and
    fully-specified `weights`.
    """
    # Create very separate clusters; check that vertices are unique and
    # correspond to classes
    class_sep = 1e6
    make = partial(make_classification, class_sep=class_sep, n_redundant=0,
                   n_repeated=0, flip_y=0, shift=0, scale=1, shuffle=False)

    for n_informative, weights, n_clusters_per_class in [(2, [1], 1),
                                                         (2, [1/3] * 3, 1),
                                                         (2, [1/4] * 4, 1),
                                                         (2, [1/2] * 2, 2),
                                                         (2, [3/4, 1/4], 2),
                                                         (10, [1/3] * 3, 10),
                                                         (np.int(64), [1], 1)
                                                         ]:
        n_classes = len(weights)
        n_clusters = n_classes * n_clusters_per_class
        n_samples = n_clusters * 50

        for hypercube in (False, True):
            X, y = make(n_samples=n_samples, n_classes=n_classes,
                        weights=weights, n_features=n_informative,
                        n_informative=n_informative,
                        n_clusters_per_class=n_clusters_per_class,
                        hypercube=hypercube, random_state=0)

            assert X.shape == (n_samples, n_informative)
            assert y.shape == (n_samples,)

            # Cluster by sign, viewed as strings to allow uniquing
            signs = np.sign(X)
            signs = signs.view(dtype='|S{0}'.format(signs.strides[0]))
            unique_signs, cluster_index = np.unique(signs,
                                                    return_inverse=True)

            assert len(unique_signs) == n_clusters, (
                "Wrong number of clusters, or not in distinct quadrants")

            clusters_by_class = defaultdict(set)
            for cluster, cls in zip(cluster_index, y):
                clusters_by_class[cls].add(cluster)
            for clusters in clusters_by_class.values():
                assert len(clusters) == n_clusters_per_class, (
                    "Wrong number of clusters per class")
            assert (len(clusters_by_class) == n_classes), (
                "Wrong number of classes")

            assert_array_almost_equal(np.bincount(y) / len(y) // weights,
                                      [1] * n_classes,
                                      err_msg="Wrong number of samples "
                                              "per class")

            # Ensure on vertices of hypercube
            for cluster in range(len(unique_signs)):
                centroid = X[cluster_index == cluster].mean(axis=0)
                if hypercube:
                    assert_array_almost_equal(np.abs(centroid) / class_sep,
                                              np.ones(n_informative),
                                              decimal=5,
                                              err_msg="Clusters are not "
                                                      "centered on hypercube "
                                                      "vertices")
                else:
                    with pytest.raises(AssertionError):
                        assert_array_almost_equal(np.abs(centroid) / class_sep,
                                                  np.ones(n_informative),
                                                  decimal=5,
                                                  err_msg="Clusters should "
                                                          "not be centered "
                                                          "on hypercube "
                                                          "vertices")

    with pytest.raises(ValueError):
        make(n_features=2, n_informative=2, n_classes=5,
             n_clusters_per_class=1)
    with pytest.raises(ValueError):
        make(n_features=2, n_informative=2, n_classes=3,
             n_clusters_per_class=2)


@pytest.mark.parametrize(
    'weights, err_type, err_msg',
    [
        ([], ValueError,
         "Weights specified but incompatible with number of classes."),
        ([.25, .75, .1], ValueError,
         "Weights specified but incompatible with number of classes."),
        (np.array([]), ValueError,
         "Weights specified but incompatible with number of classes."),
        (np.array([.25, .75, .1]), ValueError,
         "Weights specified but incompatible with number of classes."),
        (np.random.random(3), ValueError,
         "Weights specified but incompatible with number of classes.")
    ]
)
def test_make_classification_weights_type(weights, err_type, err_msg):
    with pytest.raises(err_type, match=err_msg):
        make_classification(weights=weights)


@pytest.mark.parametrize("kwargs", [{}, {"n_classes": 3, "n_informative": 3}])
def test_make_classification_weights_array_or_list_ok(kwargs):
    X1, y1 = make_classification(weights=[.1, .9],
                                 random_state=0, **kwargs)
    X2, y2 = make_classification(weights=np.array([.1, .9]),
                                 random_state=0, **kwargs)
    assert_almost_equal(X1, X2)
    assert_almost_equal(y1, y2)


def test_make_multilabel_classification_return_sequences():
    for allow_unlabeled, min_length in zip((True, False), (0, 1)):
        X, Y = make_multilabel_classification(n_samples=100, n_features=20,
                                              n_classes=3, random_state=0,
                                              return_indicator=False,
                                              allow_unlabeled=allow_unlabeled)
        assert X.shape == (100, 20), "X shape mismatch"
        if not allow_unlabeled:
            assert max([max(y) for y in Y]) == 2
        assert min([len(y) for y in Y]) == min_length
        assert max([len(y) for y in Y]) <= 3


def test_make_multilabel_classification_return_indicator():
    for allow_unlabeled, min_length in zip((True, False), (0, 1)):
        X, Y = make_multilabel_classification(n_samples=25, n_features=20,
                                              n_classes=3, random_state=0,
                                              allow_unlabeled=allow_unlabeled)
        assert X.shape == (25, 20), "X shape mismatch"
        assert Y.shape == (25, 3), "Y shape mismatch"
        assert np.all(np.sum(Y, axis=0) > min_length)

    # Also test return_distributions and return_indicator with True
    X2, Y2, p_c, p_w_c = make_multilabel_classification(
        n_samples=25, n_features=20, n_classes=3, random_state=0,
        allow_unlabeled=allow_unlabeled, return_distributions=True)

    assert_array_almost_equal(X, X2)
    assert_array_equal(Y, Y2)
    assert p_c.shape == (3,)
    assert_almost_equal(p_c.sum(), 1)
    assert p_w_c.shape == (20, 3)
    assert_almost_equal(p_w_c.sum(axis=0), [1] * 3)


def test_make_multilabel_classification_return_indicator_sparse():
    for allow_unlabeled, min_length in zip((True, False), (0, 1)):
        X, Y = make_multilabel_classification(n_samples=25, n_features=20,
                                              n_classes=3, random_state=0,
                                              return_indicator='sparse',
                                              allow_unlabeled=allow_unlabeled)
        assert X.shape == (25, 20), "X shape mismatch"
        assert Y.shape == (25, 3), "Y shape mismatch"
        assert sp.issparse(Y)


def test_make_hastie_10_2():
    X, y = make_hastie_10_2(n_samples=100, random_state=0)
    assert X.shape == (100, 10), "X shape mismatch"
    assert y.shape == (100,), "y shape mismatch"
    assert np.unique(y).shape == (2,), "Unexpected number of classes"


def test_make_regression():
    X, y, c = make_regression(n_samples=100, n_features=10, n_informative=3,
                              effective_rank=5, coef=True, bias=0.0,
                              noise=1.0, random_state=0)

    assert X.shape == (100, 10), "X shape mismatch"
    assert y.shape == (100,), "y shape mismatch"
    assert c.shape == (10,), "coef shape mismatch"
    assert sum(c != 0.0) == 3, "Unexpected number of informative features"

    # Test that y ~= np.dot(X, c) + bias + N(0, 1.0).
    assert_almost_equal(np.std(y - np.dot(X, c)), 1.0, decimal=1)

    # Test with small number of features.
    X, y = make_regression(n_samples=100, n_features=1)  # n_informative=3
    assert X.shape == (100, 1)


def test_make_regression_multitarget():
    X, y, c = make_regression(n_samples=100, n_features=10, n_informative=3,
                              n_targets=3, coef=True, noise=1., random_state=0)

    assert X.shape == (100, 10), "X shape mismatch"
    assert y.shape == (100, 3), "y shape mismatch"
    assert c.shape == (10, 3), "coef shape mismatch"
    assert_array_equal(sum(c != 0.0), 3,
                       "Unexpected number of informative features")

    # Test that y ~= np.dot(X, c) + bias + N(0, 1.0)
    assert_almost_equal(np.std(y - np.dot(X, c)), 1.0, decimal=1)


def test_make_blobs():
    cluster_stds = np.array([0.05, 0.2, 0.4])
    cluster_centers = np.array([[0.0, 0.0], [1.0, 1.0], [0.0, 1.0]])
    X, y = make_blobs(random_state=0, n_samples=50, n_features=2,
                      centers=cluster_centers, cluster_std=cluster_stds)

    assert X.shape == (50, 2), "X shape mismatch"
    assert y.shape == (50,), "y shape mismatch"
    assert np.unique(y).shape == (3,), "Unexpected number of blobs"
    for i, (ctr, std) in enumerate(zip(cluster_centers, cluster_stds)):
        assert_almost_equal((X[y == i] - ctr).std(), std, 1, "Unexpected std")


def test_make_blobs_n_samples_list():
    n_samples = [50, 30, 20]
    X, y = make_blobs(n_samples=n_samples, n_features=2, random_state=0)

    assert X.shape == (sum(n_samples), 2), "X shape mismatch"
    assert all(np.bincount(y, minlength=len(n_samples)) == n_samples), \
        "Incorrect number of samples per blob"


def test_make_blobs_n_samples_list_with_centers():
    n_samples = [20, 20, 20]
    centers = np.array([[0.0, 0.0], [1.0, 1.0], [0.0, 1.0]])
    cluster_stds = np.array([0.05, 0.2, 0.4])
    X, y = make_blobs(n_samples=n_samples, centers=centers,
                      cluster_std=cluster_stds, random_state=0)

    assert X.shape == (sum(n_samples), 2), "X shape mismatch"
    assert all(np.bincount(y, minlength=len(n_samples)) == n_samples), \
        "Incorrect number of samples per blob"
    for i, (ctr, std) in enumerate(zip(centers, cluster_stds)):
        assert_almost_equal((X[y == i] - ctr).std(), std, 1, "Unexpected std")


@pytest.mark.parametrize(
    "n_samples",
    [[5, 3, 0],
     np.array([5, 3, 0]),
     tuple([5, 3, 0])]
)
def test_make_blobs_n_samples_centers_none(n_samples):
    centers = None
    X, y = make_blobs(n_samples=n_samples, centers=centers, random_state=0)

    assert X.shape == (sum(n_samples), 2), "X shape mismatch"
    assert all(np.bincount(y, minlength=len(n_samples)) == n_samples), \
        "Incorrect number of samples per blob"


def test_make_blobs_error():
    n_samples = [20, 20, 20]
    centers = np.array([[0.0, 0.0], [1.0, 1.0], [0.0, 1.0]])
    cluster_stds = np.array([0.05, 0.2, 0.4])
    wrong_centers_msg = ("Length of `n_samples` not consistent "
                         "with number of centers. Got n_samples = {} "
                         "and centers = {}".format(n_samples, centers[:-1]))
    assert_raise_message(ValueError, wrong_centers_msg,
                         make_blobs, n_samples, centers=centers[:-1])
    wrong_std_msg = ("Length of `clusters_std` not consistent with "
                     "number of centers. Got centers = {} "
                     "and cluster_std = {}".format(centers, cluster_stds[:-1]))
    assert_raise_message(ValueError, wrong_std_msg,
                         make_blobs, n_samples,
                         centers=centers, cluster_std=cluster_stds[:-1])
    wrong_type_msg = ("Parameter `centers` must be array-like. "
                      "Got {!r} instead".format(3))
    assert_raise_message(ValueError, wrong_type_msg,
                         make_blobs, n_samples, centers=3)


def test_make_friedman1():
    X, y = make_friedman1(n_samples=5, n_features=10, noise=0.0,
                          random_state=0)

    assert X.shape == (5, 10), "X shape mismatch"
    assert y.shape == (5,), "y shape mismatch"

    assert_array_almost_equal(y,
                              10 * np.sin(np.pi * X[:, 0] * X[:, 1])
                              + 20 * (X[:, 2] - 0.5) ** 2
                              + 10 * X[:, 3] + 5 * X[:, 4])


def test_make_friedman2():
    X, y = make_friedman2(n_samples=5, noise=0.0, random_state=0)

    assert X.shape == (5, 4), "X shape mismatch"
    assert y.shape == (5,), "y shape mismatch"

    assert_array_almost_equal(y,
                              (X[:, 0] ** 2
                               + (X[:, 1] * X[:, 2] - 1
                                  / (X[:, 1] * X[:, 3])) ** 2) ** 0.5)


def test_make_friedman3():
    X, y = make_friedman3(n_samples=5, noise=0.0, random_state=0)

    assert X.shape == (5, 4), "X shape mismatch"
    assert y.shape == (5,), "y shape mismatch"

    assert_array_almost_equal(y, np.arctan((X[:, 1] * X[:, 2]
                                            - 1 / (X[:, 1] * X[:, 3]))
                                           / X[:, 0]))


def test_make_low_rank_matrix():
    X = make_low_rank_matrix(n_samples=50, n_features=25, effective_rank=5,
                             tail_strength=0.01, random_state=0)

    assert X.shape == (50, 25), "X shape mismatch"

    from numpy.linalg import svd
    u, s, v = svd(X)
    assert sum(s) - 5 < 0.1, "X rank is not approximately 5"


def test_make_sparse_coded_signal():
    Y, D, X = make_sparse_coded_signal(n_samples=5, n_components=8,
                                       n_features=10, n_nonzero_coefs=3,
                                       random_state=0)
    assert Y.shape == (10, 5), "Y shape mismatch"
    assert D.shape == (10, 8), "D shape mismatch"
    assert X.shape == (8, 5), "X shape mismatch"
    for col in X.T:
        assert len(np.flatnonzero(col)) == 3, 'Non-zero coefs mismatch'
    assert_array_almost_equal(np.dot(D, X), Y)
    assert_array_almost_equal(np.sqrt((D ** 2).sum(axis=0)),
                              np.ones(D.shape[1]))


def test_make_sparse_uncorrelated():
    X, y = make_sparse_uncorrelated(n_samples=5, n_features=10, random_state=0)

    assert X.shape == (5, 10), "X shape mismatch"
    assert y.shape == (5,), "y shape mismatch"


def test_make_spd_matrix():
    X = make_spd_matrix(n_dim=5, random_state=0)

    assert X.shape == (5, 5), "X shape mismatch"
    assert_array_almost_equal(X, X.T)

    from numpy.linalg import eig
    eigenvalues, _ = eig(X)
    assert_array_equal(eigenvalues > 0, np.array([True] * 5),
                       "X is not positive-definite")


def test_make_swiss_roll():
    X, t = make_swiss_roll(n_samples=5, noise=0.0, random_state=0)

    assert X.shape == (5, 3), "X shape mismatch"
    assert t.shape == (5,), "t shape mismatch"
    assert_array_almost_equal(X[:, 0], t * np.cos(t))
    assert_array_almost_equal(X[:, 2], t * np.sin(t))


def test_make_s_curve():
    X, t = make_s_curve(n_samples=5, noise=0.0, random_state=0)

    assert X.shape == (5, 3), "X shape mismatch"
    assert t.shape == (5,), "t shape mismatch"
    assert_array_almost_equal(X[:, 0], np.sin(t))
    assert_array_almost_equal(X[:, 2], np.sign(t) * (np.cos(t) - 1))


def test_make_biclusters():
    X, rows, cols = make_biclusters(
        shape=(100, 100), n_clusters=4, shuffle=True, random_state=0)
    assert X.shape == (100, 100), "X shape mismatch"
    assert rows.shape == (4, 100), "rows shape mismatch"
    assert cols.shape == (4, 100,), "columns shape mismatch"
    assert_all_finite(X)
    assert_all_finite(rows)
    assert_all_finite(cols)

    X2, _, _ = make_biclusters(shape=(100, 100), n_clusters=4,
                               shuffle=True, random_state=0)
    assert_array_almost_equal(X, X2)


def test_make_checkerboard():
    X, rows, cols = make_checkerboard(
        shape=(100, 100), n_clusters=(20, 5),
        shuffle=True, random_state=0)
    assert X.shape == (100, 100), "X shape mismatch"
    assert rows.shape == (100, 100), "rows shape mismatch"
    assert cols.shape == (100, 100,), "columns shape mismatch"

    X, rows, cols = make_checkerboard(
        shape=(100, 100), n_clusters=2, shuffle=True, random_state=0)
    assert_all_finite(X)
    assert_all_finite(rows)
    assert_all_finite(cols)

    X1, _, _ = make_checkerboard(shape=(100, 100), n_clusters=2,
                                 shuffle=True, random_state=0)
    X2, _, _ = make_checkerboard(shape=(100, 100), n_clusters=2,
                                 shuffle=True, random_state=0)
    assert_array_almost_equal(X1, X2)


def test_make_moons():
    X, y = make_moons(3, shuffle=False)
    for x, label in zip(X, y):
        center = [0.0, 0.0] if label == 0 else [1.0, 0.5]
        dist_sqr = ((x - center) ** 2).sum()
        assert_almost_equal(dist_sqr, 1.0,
                            err_msg="Point is not on expected unit circle")


def test_make_circles():
    factor = 0.3

    for (n_samples, n_outer, n_inner) in [(7, 3, 4), (8, 4, 4)]:
        # Testing odd and even case, because in the past make_circles always
        # created an even number of samples.
        X, y = make_circles(n_samples, shuffle=False, noise=None,
                            factor=factor)
        assert X.shape == (n_samples, 2), "X shape mismatch"
        assert y.shape == (n_samples,), "y shape mismatch"
        center = [0.0, 0.0]
        for x, label in zip(X, y):
            dist_sqr = ((x - center) ** 2).sum()
            dist_exp = 1.0 if label == 0 else factor**2
            assert_almost_equal(dist_sqr, dist_exp,
                                err_msg="Point is not on expected circle")

        assert X[y == 0].shape == (n_outer, 2), (
            "Samples not correctly distributed across circles.")
        assert X[y == 1].shape == (n_inner, 2), (
            "Samples not correctly distributed across circles.")

    with pytest.raises(ValueError):
        make_circles(factor=-0.01)
    with pytest.raises(ValueError):
        make_circles(factor=1.)