import sys
from copy import copy

import numpy as np
import pytest
from hypothesis import assume, given, settings, strategies

import xgboost as xgb
from xgboost import testing as tm
from xgboost.compat import PANDAS_INSTALLED

if PANDAS_INSTALLED:
    from hypothesis.extra.pandas import column, data_frames, range_indexes
else:

    def noop(*args, **kwargs):
        pass

    column, data_frames, range_indexes = noop, noop, noop

sys.path.append("tests/python")
from test_predict import run_predict_leaf  # noqa
from test_predict import run_threaded_predict  # noqa

rng = np.random.RandomState(1994)

shap_parameter_strategy = strategies.fixed_dictionaries(
    {
        "max_depth": strategies.integers(1, 11),
        "max_leaves": strategies.integers(0, 256),
        "num_parallel_tree": strategies.sampled_from([1, 10]),
    }
).filter(lambda x: x["max_depth"] > 0 or x["max_leaves"] > 0)

predict_parameter_strategy = strategies.fixed_dictionaries(
    {
        "max_depth": strategies.integers(1, 8),
        "num_parallel_tree": strategies.sampled_from([1, 4]),
    }
)

# cupy nvrtc compilation can take a long time for the first run
pytestmark = tm.timeout(30)


class TestGPUPredict:
    def test_predict(self):
        iterations = 10
        np.random.seed(1)
        test_num_rows = [10, 1000, 5000]
        test_num_cols = [10, 50, 500]
        # This test passes for tree_method=gpu_hist and tree_method=exact. but
        # for `hist` and `approx` the floating point error accumulates faster
        # and fails even tol is set to 1e-4.  For `hist`, the mismatching rate
        # with 5000 rows is 0.04.
        for num_rows in test_num_rows:
            for num_cols in test_num_cols:
                dtrain = xgb.DMatrix(
                    np.random.randn(num_rows, num_cols),
                    label=[0, 1] * int(num_rows / 2),
                )
                dval = xgb.DMatrix(
                    np.random.randn(num_rows, num_cols),
                    label=[0, 1] * int(num_rows / 2),
                )
                dtest = xgb.DMatrix(
                    np.random.randn(num_rows, num_cols),
                    label=[0, 1] * int(num_rows / 2),
                )
                watchlist = [(dtrain, "train"), (dval, "validation")]
                res = {}
                param = {
                    "objective": "binary:logistic",
                    "eval_metric": "logloss",
                    "tree_method": "hist",
                    "device": "gpu:0",
                    "max_depth": 1,
                }
                bst = xgb.train(
                    param, dtrain, iterations, evals=watchlist, evals_result=res
                )
                assert tm.non_increasing(res["train"]["logloss"], tolerance=0.001)

                gpu_pred_train = bst.predict(dtrain, output_margin=True)
                gpu_pred_test = bst.predict(dtest, output_margin=True)
                gpu_pred_val = bst.predict(dval, output_margin=True)

                bst.set_param({"device": "cpu", "tree_method": "hist"})
                bst_cpu = copy(bst)
                cpu_pred_train = bst_cpu.predict(dtrain, output_margin=True)
                cpu_pred_test = bst_cpu.predict(dtest, output_margin=True)
                cpu_pred_val = bst_cpu.predict(dval, output_margin=True)

                np.testing.assert_allclose(cpu_pred_train, gpu_pred_train, rtol=1e-6)
                np.testing.assert_allclose(cpu_pred_val, gpu_pred_val, rtol=1e-6)
                np.testing.assert_allclose(cpu_pred_test, gpu_pred_test, rtol=1e-6)

    # Test case for a bug where multiple batch predictions made on a
    # test set produce incorrect results
    @pytest.mark.skipif(**tm.no_sklearn())
    def test_multi_predict(self):
        from sklearn.datasets import make_regression
        from sklearn.model_selection import train_test_split

        n = 1000
        X, y = make_regression(n, random_state=rng)
        X_train, X_test, y_train, y_test = train_test_split(X, y, random_state=123)
        dtrain = xgb.DMatrix(X_train, label=y_train)

        params = {}
        params["tree_method"] = "hist"
        params["device"] = "cuda:0"
        bst = xgb.train(params, dtrain)

        bst.set_param({"device": "cuda:0"})
        # Don't reuse the DMatrix for prediction, otherwise the result is cached.
        predict_gpu_0 = bst.predict(xgb.DMatrix(X_test))
        predict_gpu_1 = bst.predict(xgb.DMatrix(X_test))
        bst.set_param({"device": "cpu"})
        predict_cpu = bst.predict(xgb.DMatrix(X_test))

        assert np.allclose(predict_gpu_0, predict_gpu_1)
        assert np.allclose(predict_gpu_0, predict_cpu)

    @pytest.mark.skipif(**tm.no_sklearn())
    def test_sklearn(self):
        m, n = 15000, 14
        tr_size = 2500
        X = np.random.rand(m, n)
        y = 200 * np.matmul(X, np.arange(-3, -3 + n))
        y = y.reshape(y.size)
        X_train, y_train = X[:tr_size, :], y[:tr_size]
        X_test, y_test = X[tr_size:, :], y[tr_size:]

        params = {
            "tree_method": "hist",
            "device": "cuda:0",
            "n_jobs": -1,
            "seed": 123,
        }
        m = xgb.XGBRegressor(**params).fit(X_train, y_train)
        gpu_train_score = m.score(X_train, y_train)
        gpu_test_score = m.score(X_test, y_test)

        # Now with cpu
        m.set_params(device="cpu")
        cpu_train_score = m.score(X_train, y_train)
        cpu_test_score = m.score(X_test, y_test)

        assert np.allclose(cpu_train_score, gpu_train_score)
        assert np.allclose(cpu_test_score, gpu_test_score)

    @pytest.mark.parametrize("device", ["cpu", "cuda"])
    @pytest.mark.skipif(**tm.no_cupy())
    def test_inplace_predict_device_type(self, device: str) -> None:
        """Test inplace predict with different device and data types.

        The sklearn interface uses inplace predict by default and gbtree fallbacks to
        DMatrix whenever device doesn't match. This test checks that XGBoost can handle
        different combinations of device and input data type.

        """
        import cudf
        import cupy as cp
        import pandas as pd
        from scipy.sparse import csr_matrix

        reg = xgb.XGBRegressor(tree_method="hist", device=device)
        n_samples = 4096
        n_features = 13
        X, y, w = tm.make_regression(n_samples, n_features, use_cupy=True)
        X[X == 0.0] = 1.0

        reg.fit(X, y, sample_weight=w)
        predt_0 = reg.predict(X)

        X = cp.asnumpy(X)
        predt_1 = reg.predict(X)

        df = pd.DataFrame(X)
        predt_2 = reg.predict(df)

        df = cudf.DataFrame(X)
        predt_3 = reg.predict(df)

        X_csr = csr_matrix(X)
        predt_4 = reg.predict(X_csr)

        np.testing.assert_allclose(predt_0, predt_1)
        np.testing.assert_allclose(predt_0, predt_2)
        np.testing.assert_allclose(predt_0, predt_3)
        np.testing.assert_allclose(predt_0, predt_4)

    def run_inplace_base_margin(self, booster, dtrain, X, base_margin):
        import cupy as cp

        dtrain.set_info(base_margin=base_margin)
        from_inplace = booster.inplace_predict(data=X, base_margin=base_margin)
        from_dmatrix = booster.predict(dtrain)
        cp.testing.assert_allclose(from_inplace, from_dmatrix)

    def run_inplace_predict_cupy(self, device: int) -> None:
        import cupy as cp

        cp.cuda.runtime.setDevice(device)
        rows = 1000
        cols = 10
        missing = 11  # set to integer for testing

        cp_rng = cp.random.RandomState(1994)
        cp.random.set_random_state(cp_rng)

        X = cp.random.randn(rows, cols)
        missing_idx = [i for i in range(0, cols, 4)]
        X[:, missing_idx] = missing  # set to be missing
        y = cp.random.randn(rows)

        dtrain = xgb.DMatrix(X, y)

        booster = xgb.train(
            {"tree_method": "hist", "device": f"cuda:{device}"},
            dtrain,
            num_boost_round=10,
        )

        test = xgb.DMatrix(X[:10, ...], missing=missing)
        predt_from_array = booster.inplace_predict(X[:10, ...], missing=missing)
        predt_from_dmatrix = booster.predict(test)
        cp.testing.assert_allclose(predt_from_array, predt_from_dmatrix)

        def predict_dense(x):
            cp.cuda.runtime.setDevice(device)
            inplace_predt = booster.inplace_predict(x)
            d = xgb.DMatrix(x)
            copied_predt = cp.array(booster.predict(d))
            return cp.all(copied_predt == inplace_predt)

        # Don't do this on Windows, see issue #5793
        if sys.platform.startswith("win"):
            pytest.skip(
                "Multi-threaded in-place prediction with cuPy is not working on Windows"
            )
        for i in range(10):
            run_threaded_predict(X, rows, predict_dense)

        base_margin = cp_rng.randn(rows)
        self.run_inplace_base_margin(booster, dtrain, X, base_margin)

        # Create a wide dataset
        X = cp_rng.randn(100, 10000)
        y = cp_rng.randn(100)

        missing_idx = [i for i in range(0, X.shape[1], 16)]
        X[:, missing_idx] = missing
        reg = xgb.XGBRegressor(
            tree_method="hist", n_estimators=8, missing=missing, device=f"cuda:{device}"
        )
        reg.fit(X, y)

        reg.set_params(device=f"cuda:{device}")
        gpu_predt = reg.predict(X)
        reg = reg.set_params(device="cpu")
        cpu_predt = reg.predict(cp.asnumpy(X))
        np.testing.assert_allclose(gpu_predt, cpu_predt, atol=1e-6)
        cp.cuda.runtime.setDevice(0)

    @pytest.mark.skipif(**tm.no_cupy())
    def test_inplace_predict_cupy(self):
        self.run_inplace_predict_cupy(0)

    @pytest.mark.skipif(**tm.no_cupy())
    @pytest.mark.mgpu
    def test_inplace_predict_cupy_specified_device(self):
        import cupy as cp

        n_devices = cp.cuda.runtime.getDeviceCount()
        for d in range(n_devices):
            self.run_inplace_predict_cupy(d)

    @pytest.mark.skipif(**tm.no_cupy())
    @pytest.mark.skipif(**tm.no_cudf())
    def test_inplace_predict_cudf(self):
        import cudf
        import cupy as cp
        import pandas as pd

        rows = 1000
        cols = 10
        rng = np.random.RandomState(1994)
        cp.cuda.runtime.setDevice(0)
        X = rng.randn(rows, cols)
        X = pd.DataFrame(X)
        y = rng.randn(rows)
        X = cudf.from_pandas(X)

        dtrain = xgb.DMatrix(X, y)

        booster = xgb.train(
            {"tree_method": "hist", "device": "cuda:0"}, dtrain, num_boost_round=10
        )
        test = xgb.DMatrix(X)
        predt_from_array = booster.inplace_predict(X)
        predt_from_dmatrix = booster.predict(test)

        cp.testing.assert_allclose(predt_from_array, predt_from_dmatrix)

        def predict_df(x):
            # column major array
            inplace_predt = booster.inplace_predict(x.values)
            d = xgb.DMatrix(x)
            copied_predt = cp.array(booster.predict(d))
            assert cp.all(copied_predt == inplace_predt)

            inplace_predt = booster.inplace_predict(x)
            return cp.all(copied_predt == inplace_predt)

        for i in range(10):
            run_threaded_predict(X, rows, predict_df)

        base_margin = cudf.Series(rng.randn(rows))
        self.run_inplace_base_margin(booster, dtrain, X, base_margin)

    @given(
        strategies.integers(1, 10), tm.make_dataset_strategy(), shap_parameter_strategy
    )
    @settings(deadline=None, max_examples=20, print_blob=True)
    def test_shap(self, num_rounds, dataset, param):
        if dataset.name.endswith("-l1"):  # not supported by the exact tree method
            return
        param.update({"tree_method": "hist", "device": "gpu:0"})
        param = dataset.set_params(param)
        dmat = dataset.get_dmat()
        bst = xgb.train(param, dmat, num_rounds)
        test_dmat = xgb.DMatrix(dataset.X, dataset.y, dataset.w, dataset.margin)
        bst.set_param({"device": "gpu:0"})
        shap = bst.predict(test_dmat, pred_contribs=True)
        margin = bst.predict(test_dmat, output_margin=True)
        assume(len(dataset.y) > 0)
        assert np.allclose(np.sum(shap, axis=len(shap.shape) - 1), margin, 1e-3, 1e-3)

    @given(
        strategies.integers(1, 10), tm.make_dataset_strategy(), shap_parameter_strategy
    )
    @settings(deadline=None, max_examples=10, print_blob=True)
    def test_shap_interactions(self, num_rounds, dataset, param):
        if dataset.name.endswith("-l1"):  # not supported by the exact tree method
            return
        param.update({"tree_method": "hist", "device": "cuda:0"})
        param = dataset.set_params(param)
        dmat = dataset.get_dmat()
        bst = xgb.train(param, dmat, num_rounds)
        test_dmat = xgb.DMatrix(dataset.X, dataset.y, dataset.w, dataset.margin)
        bst.set_param({"device": "cuda:0"})
        shap = bst.predict(test_dmat, pred_interactions=True)
        margin = bst.predict(test_dmat, output_margin=True)
        assume(len(dataset.y) > 0)
        assert np.allclose(
            np.sum(shap, axis=(len(shap.shape) - 1, len(shap.shape) - 2)),
            margin,
            1e-3,
            1e-3,
        )

    def test_shap_categorical(self):
        X, y = tm.make_categorical(100, 20, 7, False)
        Xy = xgb.DMatrix(X, y, enable_categorical=True)
        booster = xgb.train(
            {"tree_method": "hist", "device": "gpu:0"}, Xy, num_boost_round=10
        )

        booster.set_param({"device": "cuda:0"})
        shap = booster.predict(Xy, pred_contribs=True)
        margin = booster.predict(Xy, output_margin=True)
        np.testing.assert_allclose(
            np.sum(shap, axis=len(shap.shape) - 1), margin, rtol=1e-3
        )

        booster.set_param({"device": "cpu"})
        shap = booster.predict(Xy, pred_contribs=True)
        margin = booster.predict(Xy, output_margin=True)
        np.testing.assert_allclose(
            np.sum(shap, axis=len(shap.shape) - 1), margin, rtol=1e-3
        )

    def test_predict_leaf_basic(self):
        gpu_leaf = run_predict_leaf("gpu:0")
        cpu_leaf = run_predict_leaf("cpu")
        np.testing.assert_equal(gpu_leaf, cpu_leaf)

    def run_predict_leaf_booster(self, param, num_rounds, dataset):
        param = dataset.set_params(param)
        m = dataset.get_dmat()
        booster = xgb.train(
            param, dtrain=dataset.get_dmat(), num_boost_round=num_rounds
        )
        booster.set_param({"device": "cpu"})
        cpu_leaf = booster.predict(m, pred_leaf=True)

        booster.set_param({"device": "cuda:0"})
        gpu_leaf = booster.predict(m, pred_leaf=True)

        np.testing.assert_equal(cpu_leaf, gpu_leaf)

    @given(predict_parameter_strategy, tm.make_dataset_strategy())
    @settings(deadline=None, max_examples=20, print_blob=True)
    def test_predict_leaf_gbtree(self, param: dict, dataset: tm.TestDataset) -> None:
        # Unsupported for random forest
        if param.get("num_parallel_tree", 1) > 1 and dataset.name.endswith("-l1"):
            return

        param.update({"booster": "gbtree", "tree_method": "hist", "device": "cuda:0"})
        self.run_predict_leaf_booster(param, 10, dataset)

    @given(predict_parameter_strategy, tm.make_dataset_strategy())
    @settings(deadline=None, max_examples=20, print_blob=True)
    def test_predict_leaf_dart(self, param: dict, dataset: tm.TestDataset) -> None:
        # Unsupported for random forest
        if param.get("num_parallel_tree", 1) > 1 and dataset.name.endswith("-l1"):
            return

        param.update({"booster": "dart", "tree_method": "hist", "device": "cuda:0"})
        self.run_predict_leaf_booster(param, 10, dataset)

    @pytest.mark.skipif(**tm.no_sklearn())
    @pytest.mark.skipif(**tm.no_pandas())
    @given(
        df=data_frames(
            [
                column("x0", elements=strategies.integers(min_value=0, max_value=3)),
                column("x1", elements=strategies.integers(min_value=0, max_value=5)),
            ],
            index=range_indexes(min_size=20, max_size=50),
        )
    )
    @settings(deadline=None, max_examples=20, print_blob=True)
    def test_predict_categorical_split(self, df):
        from sklearn.metrics import mean_squared_error

        df = df.astype("category")
        x0, x1 = df["x0"].to_numpy(), df["x1"].to_numpy()
        y = (x0 * 10 - 20) + (x1 - 2)
        dtrain = xgb.DMatrix(df, label=y, enable_categorical=True)

        params = {
            "tree_method": "hist",
            "max_depth": 3,
            "learning_rate": 1.0,
            "base_score": 0.0,
            "eval_metric": "rmse",
            "device": "cuda:0",
        }

        eval_history = {}
        bst = xgb.train(
            params,
            dtrain,
            num_boost_round=5,
            evals=[(dtrain, "train")],
            verbose_eval=False,
            evals_result=eval_history,
        )
        bst.set_param({"device": "cuda:0"})
        pred = bst.predict(dtrain)
        rmse = mean_squared_error(y_true=y, y_pred=pred, squared=False)
        np.testing.assert_almost_equal(
            rmse, eval_history["train"]["rmse"][-1], decimal=5
        )

    @pytest.mark.skipif(**tm.no_cupy())
    @pytest.mark.parametrize("n_classes", [2, 3])
    def test_predict_dart(self, n_classes):
        import cupy as cp
        from sklearn.datasets import make_classification

        n_samples = 1000
        X_, y_ = make_classification(
            n_samples=n_samples, n_informative=5, n_classes=n_classes
        )
        X, y = cp.array(X_), cp.array(y_)

        Xy = xgb.DMatrix(X, y)
        if n_classes == 2:
            params = {
                "tree_method": "hist",
                "device": "cuda:0",
                "booster": "dart",
                "rate_drop": 0.5,
                "objective": "binary:logistic",
            }
        else:
            params = {
                "tree_method": "hist",
                "device": "cuda:0",
                "booster": "dart",
                "rate_drop": 0.5,
                "objective": "multi:softprob",
                "num_class": n_classes,
            }

        booster = xgb.train(params, Xy, num_boost_round=32)

        # auto (GPU)
        inplace = booster.inplace_predict(X)
        copied = booster.predict(Xy)

        # CPU
        booster.set_param({"device": "cpu"})
        cpu_inplace = booster.inplace_predict(X_)
        cpu_copied = booster.predict(Xy)

        copied = cp.array(copied)
        cp.testing.assert_allclose(cpu_inplace, copied, atol=1e-6)
        cp.testing.assert_allclose(cpu_copied, copied, atol=1e-6)
        cp.testing.assert_allclose(inplace, copied, atol=1e-6)

        # GPU
        booster.set_param({"device": "cuda:0"})
        inplace = booster.inplace_predict(X)
        copied = booster.predict(Xy)

        copied = cp.array(copied)
        cp.testing.assert_allclose(inplace, copied, atol=1e-6)

    @pytest.mark.skipif(**tm.no_cupy())
    def test_dtypes(self):
        import cupy as cp

        rows = 1000
        cols = 10
        rng = cp.random.RandomState(1994)
        orig = rng.randint(low=0, high=127, size=rows * cols).reshape(rows, cols)
        y = rng.randint(low=0, high=127, size=rows)
        dtrain = xgb.DMatrix(orig, label=y)
        booster = xgb.train({"tree_method": "hist", "device": "cuda:0"}, dtrain)

        predt_orig = booster.inplace_predict(orig)
        # all primitive types in numpy
        for dtype in [
            cp.byte,
            cp.short,
            cp.intc,
            cp.int_,
            cp.longlong,
            cp.ubyte,
            cp.ushort,
            cp.uintc,
            cp.uint,
            cp.ulonglong,
            cp.half,
            cp.single,
            cp.double,
        ]:
            X = cp.array(orig, dtype=dtype)
            predt = booster.inplace_predict(X)
            cp.testing.assert_allclose(predt, predt_orig)

        # boolean
        orig = cp.random.binomial(1, 0.5, size=rows * cols).reshape(rows, cols)
        predt_orig = booster.inplace_predict(orig)
        for dtype in [cp.bool8, cp.bool_]:
            X = cp.array(orig, dtype=dtype)
            predt = booster.inplace_predict(X)
            cp.testing.assert_allclose(predt, predt_orig)

        # unsupported types
        for dtype in [
            cp.complex64,
            cp.complex128,
        ]:
            X = cp.array(orig, dtype=dtype)
            with pytest.raises(ValueError):
                booster.inplace_predict(X)
