# coding=utf-8
# Copyright 2020 The HuggingFace Datasets Authors and the current dataset script contributor.
#
# 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.

# Lint as: python3

import json

import datasets

_CITATION = '''
@article{Lawrie2022HC4,
  author = {Dawn Lawrie and James Mayfield and Douglas W. Oard and Eugene Yang},
  title = {HC4: A New Suite of Test Collections for Ad Hoc CLIR},
  booktitle = {{Advances in Information Retrieval. 44th European Conference on IR Research (ECIR 2022)},
  year = {2022},
  month = apr,
  publisher = {Springer},
  series = {Lecture Notes in Computer Science},
  site = {Stavanger, Norway},
  url = {https://arxiv.org/abs/2201.09992}
}
'''


import ir_datasets

langs = ['fa', 'ru', 'zh']
fields = ['title', 'desc', 'title_desc']
lang_fields = [f'{lang}-{field}' for lang in langs for field in fields]

_DESCRIPTION = 'dataset load script for HC4'


class HC4(datasets.GeneratorBasedBuilder):
    BUILDER_CONFIGS = [datasets.BuilderConfig(
            version=datasets.Version('1.0.0'),
            name=lf, description=f'HC4: {lf}.'
        ) for lf in lang_fields
    ]

    def _info(self):
        features = datasets.Features({
            'query_id': datasets.Value('string'),
            'query': datasets.Value('string'),
        })

        return datasets.DatasetInfo(
            # This is the description that will appear on the datasets page.
            description=_DESCRIPTION,
            # This defines the different columns of the dataset and their types
            features=features,  # Here we define them above because they are different between the two configurations
            supervised_keys=None,
            # Homepage of the dataset for documentation
            homepage='https://github.com/hltcoe/HC4',
            # License for the dataset if available
            license='',
            # Citation for the dataset
            citation=_CITATION,
        )

    def _split_generators(self, dl_manager):
        lang_field = self.config.name
        splits = [
            datasets.SplitGenerator(
                name=set_name,
                gen_kwargs={
                    'lang_field': lang_field,
                    'set_name': set_name,
                },
            ) for set_name in ['dev', 'test']
        ]
        return splits

    def _generate_examples(self, lang_field, set_name):
        lang, field = lang_field.split('-')

        if lang not in lang:
            raise ValueError(f"Unexpected language: {lang}")
        if field not in fields:
            raise ValueError(f"Unexpected field: {field}")

        dataset = ir_datasets.load(f'hc4/{lang}/{set_name}')
        for query in dataset.queries_iter():
            # all are English Questions
            if field == 'title':
                q = query.title
            elif field == "desc":
                q = query.description
            else:
                q = f"{query.title} {query.description}"
            yield query.query_id, {'query_id': query.query_id, 'query': q}