# 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.
"""No Language Left Behind (NLLB)"""

import datasets
import csv
import json

_CITATION = (
    "@article{team2022NoLL,"
    "title={No Language Left Behind: Scaling Human-Centered Machine Translation},"
    "author={Nllb team and Marta Ruiz Costa-juss{\`a} and James Cross and Onur cCelebi and Maha Elbayad and Kenneth Heafield and Kevin Heffernan and Elahe Kalbassi and Janice Lam and Daniel Licht and Jean Maillard and Anna Sun and Skyler Wang and Guillaume Wenzek and Alison Youngblood and Bapi Akula and Lo{\"i}c Barrault and Gabriel Mejia Gonzalez and Prangthip Hansanti and John Hoffman and Semarley Jarrett and Kaushik Ram Sadagopan and Dirk Rowe and Shannon L. Spruit and C. Tran and Pierre Andrews and Necip Fazil Ayan and Shruti Bhosale and Sergey Edunov and Angela Fan and Cynthia Gao and Vedanuj Goswami and Francisco Guzm'an and Philipp Koehn and Alexandre Mourachko and Christophe Ropers and Safiyyah Saleem and Holger Schwenk and Jeff Wang},"
    "journal={ArXiv},"
    "year={2022},"
    "volume={abs/2207.04672}"
    "}"
)


_DESCRIPTION = ""  # TODO

_HOMEPAGE = ""  # TODO

_LICENSE = "https://opendatacommons.org/licenses/by/1-0/"

from .nllb_lang_pairs import LANG_PAIRS as _LANGUAGE_PAIRS

_URL_BASE = "https://storage.googleapis.com/allennlp-data-bucket/nllb/"

_URLs = {
    f"{src_lg}-{trg_lg}": f"{_URL_BASE}{src_lg}-{trg_lg}.gz"
    for src_lg, trg_lg in _LANGUAGE_PAIRS
}


class NLLBTaskConfig(datasets.BuilderConfig):
    """BuilderConfig for No Language Left Behind Dataset."""

    def __init__(self, src_lg, tgt_lg, **kwargs):
        super(NLLBTaskConfig, self).__init__(**kwargs)
        self.src_lg = src_lg
        self.tgt_lg = tgt_lg


class NLLB(datasets.GeneratorBasedBuilder):
    """No Language Left Behind Dataset."""

    BUILDER_CONFIGS = [
        NLLBTaskConfig(
            name=f"{src_lg}-{tgt_lg}",
            version=datasets.Version("1.0.0"),
            description=f"No Language Left Behind (NLLB): {src_lg} - {tgt_lg}",
            src_lg=src_lg,
            tgt_lg=tgt_lg,
        )
        for (src_lg, tgt_lg) in _LANGUAGE_PAIRS
    ]
    BUILDER_CONFIG_CLASS = NLLBTaskConfig

    def _info(self):
        # define feature types
        features = datasets.Features(
            {
                "translation": datasets.Translation(
                    languages=(self.config.src_lg, self.config.tgt_lg)
                ),
                "laser_score": datasets.Value("float32"),
                "source_sentence_lid": datasets.Value("float32"),
                "target_sentence_lid": datasets.Value("float32"),
                "source_sentence_source": datasets.Value("string"),
                "source_sentence_url": datasets.Value("string"),
                "target_sentence_source": datasets.Value("string"),
                "target_sentence_url": datasets.Value("string"),
            }
        )

        return datasets.DatasetInfo(
            description=_DESCRIPTION,
            features=features,
            supervised_keys=None,
            homepage=_HOMEPAGE,
            license=_LICENSE,
            citation=_CITATION,
        )

    def _split_generators(self, dl_manager):
        """Returns SplitGenerators."""
        pair = f"{self.config.src_lg}-{self.config.tgt_lg}"  # string identifier for language pair
        url = _URLs[pair]  # url for download of pair-specific file
        data_file = dl_manager.download_and_extract(
            url
        )  # extract downloaded data and store path in data_file

        return [
            datasets.SplitGenerator(
                name=datasets.Split.TRAIN,
                gen_kwargs={
                    "filepath": data_file,
                    "source_lg": self.config.src_lg,
                    "target_lg": self.config.tgt_lg,
                },
            )
        ]

    def _generate_examples(self, filepath, source_lg, target_lg):
        with open(filepath, encoding="utf-8") as f:
            # reader = csv.reader(f, delimiter="\t")
            for id_, example in enumerate(f):
                try:
                    datarow = example.split("\t")
                    row = {}
                    row["translation"] = {
                        source_lg: datarow[0],
                        target_lg: datarow[1],
                    }  # create translation json
                    row["laser_score"] = float(datarow[2])
                    row["source_sentence_lid"] = float(datarow[3])
                    row["target_sentence_lid"] = float(datarow[4])
                    row["source_sentence_source"] = datarow[5]
                    row["source_sentence_url"] = datarow[6]
                    row["target_sentence_source"] = datarow[7]
                    row["target_sentence_url"] = datarow[8]
                    row = {
                        k: None if not v else v for k, v in row.items()
                    }  # replace empty values
                except:
                    print(datarow)
                    raise
                yield id_, row


# to test the script, go to the root folder of the repo (nllb) and run:
# datasets-cli test nllb --save_infos --all_configs