#   Copyright (c) 2020 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 math

import paddle.fluid as fluid

from paddlerec.core.utils import envs
from paddlerec.core.model import Model as ModelBase


class Model(ModelBase):
    def __init__(self, config):
        ModelBase.__init__(self, config)

    def wide_part(self, data):
        out = fluid.layers.fc(input=data,
                              size=1,
                              param_attr=fluid.ParamAttr(initializer=fluid.initializer.TruncatedNormal(loc=0.0,
                                                                                                       scale=1.0 / math.sqrt(
                                                                                                           data.shape[
                                                                                                               1])),
                                                         regularizer=fluid.regularizer.L2DecayRegularizer(
                                                             regularization_coeff=1e-4)),
                              act=None,
                              name='wide')
        return out

    def fc(self, data, hidden_units, active, tag):
        output = fluid.layers.fc(input=data,
                                 size=hidden_units,
                                 param_attr=fluid.ParamAttr(initializer=fluid.initializer.TruncatedNormal(loc=0.0,
                                                                                                          scale=1.0 / math.sqrt(
                                                                                                              data.shape[
                                                                                                                  1]))),
                                 act=active,
                                 name=tag)

        return output

    def deep_part(self, data, hidden1_units, hidden2_units, hidden3_units):
        l1 = self.fc(data, hidden1_units, 'relu', 'l1')
        l2 = self.fc(l1, hidden2_units, 'relu', 'l2')
        l3 = self.fc(l2, hidden3_units, 'relu', 'l3')

        return l3

    def train_net(self):
        wide_input = self._dense_data_var[0]
        deep_input = self._dense_data_var[1]
        label = self._sparse_data_var[0]

        hidden1_units = envs.get_global_env("hyper_parameters.hidden1_units", 75, self._namespace)
        hidden2_units = envs.get_global_env("hyper_parameters.hidden2_units", 50, self._namespace)
        hidden3_units = envs.get_global_env("hyper_parameters.hidden3_units", 25, self._namespace)
        wide_output = self.wide_part(wide_input)
        deep_output = self.deep_part(deep_input, hidden1_units, hidden2_units, hidden3_units)

        wide_model = fluid.layers.fc(input=wide_output,
                                     size=1,
                                     param_attr=fluid.ParamAttr(
                                         initializer=fluid.initializer.TruncatedNormal(loc=0.0, scale=1.0)),
                                     act=None,
                                     name='w_wide')

        deep_model = fluid.layers.fc(input=deep_output,
                                     size=1,
                                     param_attr=fluid.ParamAttr(
                                         initializer=fluid.initializer.TruncatedNormal(loc=0.0, scale=1.0)),
                                     act=None,
                                     name='w_deep')

        prediction = fluid.layers.elementwise_add(wide_model, deep_model)
        pred = fluid.layers.sigmoid(fluid.layers.clip(prediction, min=-15.0, max=15.0), name="prediction")

        num_seqs = fluid.layers.create_tensor(dtype='int64')
        acc = fluid.layers.accuracy(input=pred, label=fluid.layers.cast(x=label, dtype='int64'), total=num_seqs)
        auc_var, batch_auc, auc_states = fluid.layers.auc(input=pred, label=fluid.layers.cast(x=label, dtype='int64'))

        self._metrics["AUC"] = auc_var
        self._metrics["BATCH_AUC"] = batch_auc
        self._metrics["ACC"] = acc

        cost = fluid.layers.sigmoid_cross_entropy_with_logits(x=prediction, label=fluid.layers.cast(label, dtype='float32')) 
        avg_cost = fluid.layers.mean(cost)
        self._cost = avg_cost

    def optimizer(self):
        learning_rate = envs.get_global_env("hyper_parameters.learning_rate", None, self._namespace)
        optimizer = fluid.optimizer.Adam(learning_rate, lazy_mode=True)
        return optimizer

    def infer_net(self, parameter_list):
        self.deepfm_net()