import datasets

_CITATION = '''@article{lawrie2023overview,
  title={Overview of the TREC 2022 NeuCLIR track},
  author={Lawrie, Dawn and MacAvaney, Sean and Mayfield, James and McNamee, Paul and Oard, Douglas W and Soldaini, Luca and Yang, Eugene},
  journal={arXiv preprint arXiv:2304.12367},
  year={2023}
}'''

_EVAL_SPLIT = "test"

_LANGUAGES = {
    "fas": ["fas-Arab"],
    "rus": ["rus-Cyrl"],
    "zho": ["zho-Hans"],
}

_DESCRIPTION = 'Dataset load script for NeuCLIR2023 downsampled for MTEB'

_DATASET_URLS = {
    lang: f'mteb/NeuCLIR2022Retrieval_{lang}_top_250_only_w_correct-v2'
    for lang in _LANGUAGES
}

class MLDR(datasets.GeneratorBasedBuilder):
    BUILDER_CONFIGS = [
        datasets.BuilderConfig(
            version=datasets.Version('1.0.0'),
            name=lang,
            description=f'NeuCLIR dataset in language {lang}.'
        ) for lang in _LANGUAGES
    ] + [
        datasets.BuilderConfig(
            version=datasets.Version('1.0.0'),
            name=f'corpus-{lang}',
            description=f'Corpus of NeuCLIR dataset in language {lang}.'
        ) for lang in _LANGUAGES
    ] + [
        datasets.BuilderConfig(
            version=datasets.Version('1.0.0'),
            name=f'queries-{lang}',
            description=f'Queries of NeuCLIR dataset in language {lang}.'
        ) for lang in _LANGUAGES
    ]

    def _info(self):
        name = self.config.name
        if name.startswith('corpus-'):
            features = datasets.Features({
                '_id': datasets.Value('string'),
                'text': datasets.Value('string'),
                'title': datasets.Value('string'),
            })
        elif name.startswith('queries-'):
            features = datasets.Features({
                '_id': datasets.Value('string'),
                'text': datasets.Value('string'),
            })
        else:
            features = datasets.Features({
                'query-id': datasets.Value('string'),
                'corpus-id': datasets.Value('string'),
                'score': datasets.Value('int32'),
            })

        return datasets.DatasetInfo(
            description=_DESCRIPTION,
            features=features,
            supervised_keys=None,
            homepage='https://arxiv.org/abs/2304.12367',
            license=None,
            citation=_CITATION,
        )

    def _split_generators(self, dl_manager):
        name = self.config.name
        lang = name.split('-')[-1] if '-' in name else name
        lang_repo = _DATASET_URLS[lang]

        if name.startswith('corpus-'):
            dataset = datasets.load_dataset(lang_repo, f"corpus")
            return [
                datasets.SplitGenerator(
                    name='corpus',
                    gen_kwargs={
                        'split': dataset['test'],
                    },
                ),
            ]
        elif name.startswith('queries-'):
            dataset = datasets.load_dataset(lang_repo, f"queries")
            return [
                datasets.SplitGenerator(
                    name='queries',
                    gen_kwargs={
                        'split': dataset['test'],
                    },
                ),
            ]
        else:
            dataset = datasets.load_dataset(lang_repo)
            return [
                datasets.SplitGenerator(
                    name=_EVAL_SPLIT,
                    gen_kwargs={
                        'split': dataset['test'],
                    },
                ),
            ]

    def _generate_examples(self, split):
        name = self.config.name
        if name.startswith('corpus-'):
            for idx, example in enumerate(split):
                yield idx, {
                    '_id': example['_id'],
                    'text': example['text'],
                    'title': example['title'],
                }
        elif name.startswith('queries-'):
            for idx, example in enumerate(split):
                yield idx, {
                    '_id': example['_id'],
                    'text': example['text'],
                }
        else:
            for idx, example in enumerate(split):
                yield idx, {
                    'query-id': example['query-id'],
                    'corpus-id': example['corpus-id'],
                    'score': example['score'],
                }