# Copyright 2020 Huawei Technologies Co., Ltd
#
# 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 numpy as np

import mindspore.nn as nn
from mindspore import Tensor, Parameter
from mindspore import context
from mindspore.common import dtype as mstype
from mindspore.nn.optim import Momentum
from mindspore.ops import functional as F
from mindspore.ops import operations as P
from mindspore.train import Model
from mindspore.train.loss_scale_manager import FixedLossScaleManager
from ....dataset_mock import MindData

context.set_context(mode=context.GRAPH_MODE)


class MindDataSet(MindData):
    def __init__(self, dataset_types, dataset_shapes):
        super(MindDataSet, self).__init__(size=2, batch_size=32,
                                          np_types=dataset_types,
                                          output_shapes=dataset_shapes,
                                          input_indexs=(0, 1))

    def __next__(self):
        if self._size < self._iter_num:
            raise StopIteration
        self._iter_num += 1
        next_ = []
        for shape, type_ in zip(self._output_shapes, self._np_types):
            next_.append(Tensor(np.ones(shape).astype(type_)))
        return tuple(next_)


class Net(nn.Cell):
    def __init__(self, in_features, out_features):
        super(Net, self).__init__()
        self.weight = Parameter(Tensor(np.ones([out_features, in_features]).astype(np.float32)), name="weight")
        self.bias = Parameter(Tensor(np.ones([out_features]).astype(np.float32)), name="bias")
        self.matmul = P.MatMul()
        self.add = P.TensorAdd()

    def construct(self, input_):
        output = self.add(self.matmul(input_, self.weight), self.bias)
        return output


class NetFP16(nn.Cell):
    def __init__(self, in_features, out_features):
        super(NetFP16, self).__init__()
        self.weight = Parameter(Tensor(np.ones([out_features, in_features]).astype(np.float32)), name="weight")
        self.bias = Parameter(Tensor(np.ones([out_features]).astype(np.float32)), name="bias")
        self.matmul = P.MatMul()
        self.add = P.TensorAdd()
        self.cast = P.Cast()

    def construct(self, input_):
        output = self.cast(
            self.add(self.matmul(self.cast(input_, mstype.float16), self.cast(self.weight, mstype.float16)),
                     self.cast(self.bias, mstype.float16)), mstype.float32)
        return output


def get_axis(x):
    shape_op = P.Shape()
    shape = shape_op(x)
    length = F.tuple_len(shape)
    perm = F.make_range(0, length)
    return perm


class MSELoss(nn.Cell):
    def __init__(self):
        super(MSELoss, self).__init__()
        self.reduce_sum = P.ReduceSum()
        self.square = P.Square()
        self.reduce_mean = P.ReduceMean()

    def construct(self, data, label):
        diff = data - label
        return self.reduce_mean(self.square(diff), get_axis(diff))


def test_auto_parallel_flag():
    context.set_auto_parallel_context(parallel_mode="auto_parallel", device_num=1)
    dataset_types = (np.float32, np.float32)
    dataset_shapes = ((16, 16), (16, 16))

    dataset = MindDataSet(dataset_types, dataset_shapes)
    net = NetFP16(16, 16)
    net.set_train()
    scale_manager = FixedLossScaleManager()
    loss = MSELoss()
    optimizer = Momentum(net.trainable_params(), learning_rate=0.1, momentum=0.9)
    model = Model(net, loss_fn=loss, optimizer=optimizer, metrics=None, loss_scale_manager=scale_manager)
    model.train(2, dataset)
    assert model._train_network.get_flags()["auto_parallel"]
    context.reset_auto_parallel_context()