from typing import List

import datasets

from .common import TrainValidTestChild
from .generated_definitions import DEFINITIONS


_DESCRIPTION = """The dataset is collected from several public repos, including Lucene(http://lucene.apache.org/), POI(http://poi.apache.org/), JGit(https://github.com/eclipse/jgit/) and Antlr(https://github.com/antlr/).
        We collect both the Java and C# versions of the codes and find the parallel functions. After removing duplicates and functions with the empty body, we split the whole dataset into training, validation and test sets."""
_CITATION = """@article{DBLP:journals/corr/abs-2102-04664,
  author    = {Shuai Lu and
               Daya Guo and
               Shuo Ren and
               Junjie Huang and
               Alexey Svyatkovskiy and
               Ambrosio Blanco and
               Colin B. Clement and
               Dawn Drain and
               Daxin Jiang and
               Duyu Tang and
               Ge Li and
               Lidong Zhou and
               Linjun Shou and
               Long Zhou and
               Michele Tufano and
               Ming Gong and
               Ming Zhou and
               Nan Duan and
               Neel Sundaresan and
               Shao Kun Deng and
               Shengyu Fu and
               Shujie Liu},
  title     = {CodeXGLUE: {A} Machine Learning Benchmark Dataset for Code Understanding
               and Generation},
  journal   = {CoRR},
  volume    = {abs/2102.04664},
  year      = {2021}
}"""


class CodeXGlueCcCodeToCodeTransImpl(TrainValidTestChild):
    _DESCRIPTION = _DESCRIPTION
    _CITATION = _CITATION

    _FEATURES = {
        "id": datasets.Value("int32"),  # Index of the sample
        "java": datasets.Value("string"),  # The java version of the code
        "cs": datasets.Value("string"),  # The C# version of the code
    }

    def generate_urls(self, split_name):
        for key in "cs", "java":
            yield key, f"{split_name}.java-cs.txt.{key}"

    def _generate_examples(self, split_name, file_paths):
        """This function returns the examples in the raw (text) form."""
        # Open each file (one for java, and one for c#)
        files = {k: open(file_paths[k], encoding="utf-8") for k in file_paths}

        id_ = 0
        while True:
            # Read a single line from each file
            entries = {k: files[k].readline() for k in file_paths}

            empty = self.check_empty(entries)
            if empty:
                # We are done: end of files
                return

            entries["id"] = id_
            yield id_, entries
            id_ += 1


CLASS_MAPPING = {
    "CodeXGlueCcCodeToCodeTrans": CodeXGlueCcCodeToCodeTransImpl,
}


class CodeXGlueCcCodeToCodeTrans(datasets.GeneratorBasedBuilder):
    BUILDER_CONFIG_CLASS = datasets.BuilderConfig
    BUILDER_CONFIGS = [
        datasets.BuilderConfig(name=name, description=info["description"]) for name, info in DEFINITIONS.items()
    ]

    def _info(self):
        name = self.config.name
        info = DEFINITIONS[name]
        if info["class_name"] in CLASS_MAPPING:
            self.child = CLASS_MAPPING[info["class_name"]](info)
        else:
            raise RuntimeError(f"Unknown python class for dataset configuration {name}")
        ret = self.child._info()
        return ret

    def _split_generators(self, dl_manager: datasets.DownloadManager) -> List[datasets.SplitGenerator]:
        return self.child._split_generators(dl_manager=dl_manager)

    def _generate_examples(self, split_name, file_paths):
        return self.child._generate_examples(split_name, file_paths)