# Copyright (c) 2023 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 unittest

import numpy as np

import paddle
import paddle.distributed as dist
from paddle.autograd.py_layer import PyLayer


class TestNet(PyLayer):
    @staticmethod
    def forward(ctx, x1, x2, x3):
        y1 = paddle.matmul(x1, x2, transpose_x=False, transpose_y=False)
        y2 = paddle.matmul(x2, x3, transpose_x=False, transpose_y=False)
        return y1, y2

    @staticmethod
    def backward(ctx, dy1, dy2):
        return dy1, dy2, dy2


class TestPyLayerForSemiAutoParallel(unittest.TestCase):
    def run_test_case(self):
        mesh = dist.ProcessMesh([0, 1], dim_names=["x"])

        x1_np = np.random.random(size=[64, 32]).astype(np.float32)
        x2_np = np.random.random(size=[32, 48]).astype(np.float32)
        x3_np = np.random.random(size=[48, 64]).astype(np.float32)
        x1 = paddle.to_tensor(x1_np)
        x2 = paddle.to_tensor(x2_np)
        x3 = paddle.to_tensor(x3_np)
        x1.stop_gradient = False
        x2.stop_gradient = False
        x3.stop_gradient = False

        dist_x1 = dist.shard_tensor(x1_np, mesh, [dist.Replicate()])
        dist_x2 = dist.shard_tensor(x2_np, mesh, [dist.Replicate()])
        dist_x3 = dist.shard_tensor(x3_np, mesh, [dist.Replicate()])
        dist_x1.stop_gradient = False
        dist_x2.stop_gradient = False
        dist_x3.stop_gradient = False

        y1, y2 = TestNet.apply(x1, x2, x3)
        loss = y1.sum()

        dist_y1, dist_y2 = TestNet.apply(dist_x1, dist_x2, dist_x3)
        dist_loss = dist_y1.sum()

        np.testing.assert_allclose(
            loss.numpy(), dist_loss.numpy(), rtol=1e-04, verbose=True
        )

        loss.backward()
        dist_loss.backward()

        np.testing.assert_allclose(
            x1.grad.numpy(), dist_x1.grad.numpy(), rtol=1e-04, verbose=True
        )
        np.testing.assert_allclose(
            x2.grad.numpy(), dist_x2.grad.numpy(), rtol=1e-04, verbose=True
        )
        np.testing.assert_allclose(
            x3.grad.numpy(), dist_x3.grad.numpy(), rtol=1e-04, verbose=True
        )


if __name__ == '__main__':
    TestPyLayerForSemiAutoParallel().run_test_case()