#   Copyright (c) 2021 PaddlePaddle Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import copy
import itertools
import unittest

import numpy as np
import scipy
import scipy.linalg
from eager_op_test import OpTest

import paddle
from paddle import fluid
from paddle.fluid import core


def scipy_lu_unpack(A):
    shape = A.shape
    if len(shape) == 2:
        return scipy.linalg.lu(A)
    else:
        preshape = shape[:-2]
        batchsize = np.product(shape) // (shape[-2] * shape[-1])
        Plst = []
        Llst = []
        Ulst = []

        NA = A.reshape((-1, shape[-2], shape[-1]))
        for b in range(batchsize):
            As = NA[b]
            P, L, U = scipy.linalg.lu(As)

            pshape = P.shape
            lshape = L.shape
            ushape = U.shape

            Plst.append(P)
            Llst.append(L)
            Ulst.append(U)

        return (
            np.array(Plst).reshape(preshape + pshape),
            np.array(Llst).reshape(preshape + lshape),
            np.array(Ulst).reshape(preshape + ushape),
        )


def Pmat_to_perm(Pmat_org, cut):
    Pmat = copy.deepcopy(Pmat_org)
    shape = Pmat.shape
    rows = shape[-2]
    cols = shape[-1]
    batchsize = max(1, np.product(shape[:-2]))
    P = Pmat.reshape(batchsize, rows, cols)
    permmat = []
    for b in range(batchsize):
        permlst = []
        sP = P[b]
        for c in range(min(rows, cols)):
            idx = np.argmax(sP[:, c])
            permlst.append(idx)
            tmp = copy.deepcopy(sP[c, :])
            sP[c, :] = sP[idx, :]
            sP[idx, :] = tmp

        permmat.append(permlst)
    Pivot = (
        np.array(permmat).reshape(
            list(shape[:-2])
            + [
                rows,
            ]
        )
        + 1
    )

    return Pivot[..., :cut]


def perm_to_Pmat(perm, dim):
    pshape = perm.shape
    bs = int(np.product(perm.shape[:-1]).item())
    perm = perm.reshape((bs, pshape[-1]))
    oneslst = []
    for i in range(bs):
        idlst = np.arange(dim)
        perm_item = perm[i, :]
        for idx, p in enumerate(perm_item - 1):
            temp = idlst[idx]
            idlst[idx] = idlst[p]
            idlst[p] = temp

        ones = paddle.eye(dim)
        nmat = paddle.scatter(ones, paddle.to_tensor(idlst), ones)
        oneslst.append(nmat)
    return np.array(oneslst).reshape(list(pshape[:-1]) + [dim, dim])


# m > n
class TestLU_UnpackOp(OpTest):
    """
    case 1
    """

    def config(self):
        self.x_shape = [2, 12, 10]
        self.unpack_ludata = True
        self.unpack_pivots = True
        self.dtype = "float64"

    def set_output(self, A):
        sP, sL, sU = scipy_lu_unpack(A)
        self.L = sL
        self.U = sU
        self.P = sP

    def setUp(self):
        self.op_type = "lu_unpack"
        self.python_api = paddle.tensor.linalg.lu_unpack
        self.python_out_sig = ["Pmat", "L", "U"]
        self.config()
        x = np.random.random(self.x_shape).astype(self.dtype)
        if paddle.in_dynamic_mode():
            xt = paddle.to_tensor(x)
            lu, pivots = paddle.linalg.lu(xt)
            lu = lu.numpy()
            pivots = pivots.numpy()
        else:
            with fluid.program_guard(fluid.Program(), fluid.Program()):
                place = fluid.CPUPlace()
                if core.is_compiled_with_cuda():
                    place = fluid.CUDAPlace(0)
                xv = paddle.static.data(
                    name="input", shape=self.x_shape, dtype=self.dtype
                )
                lu, p = paddle.linalg.lu(xv)
                exe = fluid.Executor(place)
                fetches = exe.run(
                    fluid.default_main_program(),
                    feed={"input": x},
                    fetch_list=[lu, p],
                )
                lu, pivots = fetches[0], fetches[1]

        self.inputs = {'X': lu, 'Pivots': pivots}

        self.attrs = {
            'unpack_ludata': self.unpack_ludata,
            'unpack_pivots': self.unpack_pivots,
        }
        self.set_output(x)
        self.outputs = {
            'Pmat': self.P,
            'L': self.L,
            'U': self.U,
        }

    def test_check_output(self):
        self.check_output()

    def test_check_grad(self):
        self.check_grad(['X'], ['L', 'U'])


# m = n
class TestLU_UnpackOp2(TestLU_UnpackOp):
    """
    case 2
    """

    def config(self):
        self.x_shape = [2, 10, 10]
        self.unpack_ludata = True
        self.unpack_pivots = True
        self.dtype = "float64"


# m < n
class TestLU_UnpackOp3(TestLU_UnpackOp):
    """
    case 3
    """

    def config(self):
        self.x_shape = [2, 10, 12]
        self.unpack_ludata = True
        self.unpack_pivots = True
        self.dtype = "float64"


# batchsize = 0
class TestLU_UnpackOp4(TestLU_UnpackOp):
    """
    case 4
    """

    def config(self):
        self.x_shape = [10, 12]
        self.unpack_ludata = True
        self.unpack_pivots = True
        self.dtype = "float64"


class TestLU_UnpackAPI(unittest.TestCase):
    def setUp(self):
        np.random.seed(2022)

    def test_dygraph(self):
        def run_lu_unpack_dygraph(shape, dtype):
            if dtype == "float32":
                np_dtype = np.float32
            elif dtype == "float64":
                np_dtype = np.float64
            a = np.random.rand(*shape).astype(np_dtype)
            m = a.shape[-2]
            n = a.shape[-1]
            min_mn = min(m, n)

            places = [fluid.CPUPlace()]
            if core.is_compiled_with_cuda():
                places.append(fluid.CUDAPlace(0))
            for place in places:
                paddle.disable_static(place)

                x = paddle.to_tensor(a, dtype=dtype)
                sP, sL, sU = scipy_lu_unpack(a)
                LU, P = paddle.linalg.lu(x)
                pP, pL, pU = paddle.linalg.lu_unpack(LU, P)

                np.testing.assert_allclose(sU, pU, rtol=1e-05, atol=1e-05)
                np.testing.assert_allclose(sL, pL, rtol=1e-05, atol=1e-05)
                np.testing.assert_allclose(sP, pP, rtol=1e-05, atol=1e-05)

        tensor_shapes = [
            (3, 5),
            (5, 5),
            (5, 3),  # 2-dim Tensors
            (2, 3, 5),
            (3, 5, 5),
            (4, 5, 3),  # 3-dim Tensors
            (2, 5, 3, 5),
            (3, 5, 5, 5),
            (4, 5, 5, 3),  # 4-dim Tensors
        ]
        dtypes = ["float32", "float64"]
        for tensor_shape, dtype in itertools.product(tensor_shapes, dtypes):
            run_lu_unpack_dygraph(tensor_shape, dtype)

    def test_static(self):
        paddle.enable_static()

        def run_lu_static(shape, dtype):
            if dtype == "float32":
                np_dtype = np.float32
            elif dtype == "float64":
                np_dtype = np.float64
            a = np.random.rand(*shape).astype(np_dtype)
            m = a.shape[-2]
            n = a.shape[-1]
            min_mn = min(m, n)

            places = [fluid.CPUPlace()]
            if core.is_compiled_with_cuda():
                places.append(fluid.CUDAPlace(0))
            for place in places:
                with fluid.program_guard(fluid.Program(), fluid.Program()):
                    sP, sL, sU = scipy_lu_unpack(a)

                    x = paddle.static.data(
                        name="input", shape=shape, dtype=dtype
                    )
                    lu, p = paddle.linalg.lu(x)
                    pP, pL, pU = paddle.linalg.lu_unpack(lu, p)
                    exe = fluid.Executor(place)
                    fetches = exe.run(
                        fluid.default_main_program(),
                        feed={"input": a},
                        fetch_list=[pP, pL, pU],
                    )
                    np.testing.assert_allclose(
                        fetches[0], sP, rtol=1e-05, atol=1e-05
                    )
                    np.testing.assert_allclose(
                        fetches[1], sL, rtol=1e-05, atol=1e-05
                    )
                    np.testing.assert_allclose(
                        fetches[2], sU, rtol=1e-05, atol=1e-05
                    )

        tensor_shapes = [
            (3, 5),
            (5, 5),
            (5, 3),  # 2-dim Tensors
            (2, 3, 5),
            (3, 5, 5),
            (4, 5, 3),  # 3-dim Tensors
            (2, 5, 3, 5),
            (3, 5, 5, 5),
            (4, 5, 5, 3),  # 4-dim Tensors
        ]
        dtypes = ["float32", "float64"]
        for tensor_shape, dtype in itertools.product(tensor_shapes, dtypes):
            run_lu_static(tensor_shape, dtype)


if __name__ == "__main__":
    paddle.enable_static()
    unittest.main()
