# Copyright (c) 2018 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.fluid as fluid
from paddle.fluid import core
from paddle.fluid.optimizer import SGDOptimizer
import paddle.fluid.dygraph.nn as nn
from test_imperative_base import new_program_scope
from paddle.fluid.framework import _test_eager_guard


class Policy(fluid.dygraph.Layer):
    def __init__(self, input_size):
        super(Policy, self).__init__()

        self.affine1 = nn.Linear(input_size, 128)
        self.affine2 = nn.Linear(128, 2)
        self.dropout_ratio = 0.6

        self.saved_log_probs = []
        self.rewards = []

    def forward(self, inputs):
        x = fluid.layers.reshape(inputs, shape=[-1, 4])
        x = self.affine1(x)
        x = fluid.layers.dropout(x, self.dropout_ratio)
        x = fluid.layers.relu(x)
        action_scores = self.affine2(x)
        return fluid.layers.softmax(action_scores, axis=1)


class TestImperativeMnist(unittest.TestCase):
    def test_mnist_float32(self):
        seed = 90
        epoch_num = 1

        state = np.random.normal(size=4).astype("float32")
        state_list = state.tolist()
        reward = np.random.random(size=[1, 1]).astype("float32")
        reward_list = reward.tolist()
        action_list = [1]
        action = np.array(action_list).astype("float32")
        mask_list = [[0, 1]]
        mask = np.array(mask_list).astype("float32")

        def run_dygraph():
            paddle.seed(seed)
            paddle.framework.random._manual_program_seed(seed)

            policy = Policy(input_size=4)

            dy_state = fluid.dygraph.base.to_variable(state)
            dy_state.stop_gradient = True
            loss_probs = policy(dy_state)

            dy_mask = fluid.dygraph.base.to_variable(mask)
            dy_mask.stop_gradient = True

            loss_probs = fluid.layers.log(loss_probs)
            loss_probs = fluid.layers.elementwise_mul(loss_probs, dy_mask)
            loss_probs = fluid.layers.reduce_sum(loss_probs, dim=-1)

            dy_reward = fluid.dygraph.base.to_variable(reward)
            dy_reward.stop_gradient = True

            loss_probs = fluid.layers.elementwise_mul(dy_reward, loss_probs)
            loss = fluid.layers.reduce_sum(loss_probs)

            sgd = SGDOptimizer(
                learning_rate=1e-3, parameter_list=policy.parameters()
            )

            dy_param_init_value = {}

            dy_out = loss.numpy()

            for param in policy.parameters():
                dy_param_init_value[param.name] = param.numpy()

            loss.backward()
            sgd.minimize(loss)
            policy.clear_gradients()

            dy_param_value = {}
            for param in policy.parameters():
                dy_param_value[param.name] = param.numpy()

            return dy_out, dy_param_init_value, dy_param_value

        with fluid.dygraph.guard():
            dy_out, dy_param_init_value, dy_param_value = run_dygraph()

        with fluid.dygraph.guard():
            with _test_eager_guard():
                (
                    eager_out,
                    eager_param_init_value,
                    eager_param_value,
                ) = run_dygraph()

        with new_program_scope():
            paddle.seed(seed)
            paddle.framework.random._manual_program_seed(seed)

            exe = fluid.Executor(
                fluid.CPUPlace()
                if not core.is_compiled_with_cuda()
                else fluid.CUDAPlace(0)
            )

            policy = Policy(input_size=4)

            st_sgd = SGDOptimizer(learning_rate=1e-3)

            st_state = fluid.layers.data(
                name='st_state', shape=[4], dtype='float32'
            )
            st_reward = fluid.layers.data(
                name='st_reward', shape=[1], dtype='float32'
            )
            st_mask = fluid.layers.data(
                name='st_mask', shape=[2], dtype='float32'
            )

            st_loss_probs = policy(st_state)

            st_loss_probs = fluid.layers.log(st_loss_probs)
            st_loss_probs = fluid.layers.elementwise_mul(st_loss_probs, st_mask)
            st_loss_probs = fluid.layers.reduce_sum(st_loss_probs, dim=-1)

            st_loss_probs = fluid.layers.elementwise_mul(
                st_reward, st_loss_probs
            )
            st_loss = fluid.layers.reduce_sum(st_loss_probs)

            st_sgd.minimize(st_loss)

            # initialize params and fetch them
            static_param_init_value = {}
            static_param_name_list = []
            for param in policy.parameters():
                static_param_name_list.append(param.name)

            out = exe.run(
                fluid.default_startup_program(),
                fetch_list=static_param_name_list,
            )

            for i in range(len(static_param_name_list)):
                static_param_init_value[static_param_name_list[i]] = out[i]

            fetch_list = [st_loss.name]
            fetch_list.extend(static_param_name_list)

            out = exe.run(
                fluid.default_main_program(),
                feed={"st_state": state, "st_reward": reward, "st_mask": mask},
                fetch_list=fetch_list,
            )

            static_param_value = {}
            static_out = out[0]
            for i in range(1, len(out)):
                static_param_value[static_param_name_list[i - 1]] = out[i]

        # np.testing.assert_allclose(dy_x_data.all(), static_x_data.all(), rtol=1e-5)

        for key, value in static_param_init_value.items():
            self.assertTrue(np.equal(value, dy_param_init_value[key]).all())

        self.assertTrue(np.equal(static_out, dy_out).all())

        for key, value in static_param_value.items():
            self.assertTrue(np.equal(value, dy_param_value[key]).all())

        # check eager
        for key, value in static_param_init_value.items():
            self.assertTrue(np.equal(value, eager_param_init_value[key]).all())

        self.assertTrue(np.equal(static_out, eager_out).all())

        for key, value in static_param_value.items():
            self.assertTrue(np.equal(value, eager_param_value[key]).all())


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