#coding:utf-8
#   Copyright (c) 2019  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.

from __future__ import absolute_import
from __future__ import division
from __future__ import print_function


class InputExample(object):
    """
    Input data structure of BERT/ERNIE, can satisfy single sequence task like
    text classification, sequence lableing; Sequence pair task like dialog
    task.
    """

    def __init__(self, guid, text_a, text_b=None, label=None):
        """Constructs a InputExample.
    Args:
      guid: Unique id for the example.
      text_a: string. The untokenized text of the first sequence. For single
        sequence tasks, only this sequence must be specified.
      text_b: (Optional) string. The untokenized text of the second sequence.
        Only must be specified for sequence pair tasks.
      label: (Optional) string. The label of the example. This should be
        specified for train and dev examples, but not for test examples.
    """
        self.guid = guid
        self.text_a = text_a
        self.text_b = text_b
        self.label = label

    def __str__(self):
        if self.text_b is None:
            return "text={}\tlabel={}".format(self.text_a, self.label)
        else:
            return "text_a={}\ttext_b={},label={}".format(
                self.text_a, self.text_b, self.label)


class HubDataset(object):
    def get_train_examples(self):
        raise NotImplementedError()

    def get_dev_examples(self):
        raise NotImplementedError()

    def get_test_examples(self):
        raise NotImplementedError()

    def get_val_examples(self):
        return self.get_dev_examples()

    def get_labels(self):
        raise NotImplementedError()

    def num_labels(self):
        raise NotImplementedError()