import os
import json
import datasets
import logging

logger = logging.getLogger(__name__)

_CITATION = ""
_DESCRIPTION = ""

_BASE_URL = "https://huggingface.co/datasets/JesseLiu/MedQA_Maze/resolve/main"

class MedQaMazeConfig(datasets.BuilderConfig):
    def __init__(self, **kwargs):
        super().__init__(version=datasets.Version("1.0.0"), **kwargs)

class MedQaMaze(datasets.GeneratorBasedBuilder):
    BUILDER_CONFIGS = [
        MedQaMazeConfig(name="default", description="A default config"),
        MedQaMazeConfig(name="advance", description="Advanced-level test data"),
        MedQaMazeConfig(name="all",     description="Full dataset with train and test"),
        MedQaMazeConfig(name="basic",   description="Basic-level test data"),
        MedQaMazeConfig(name="challenge", description="Challenge-level test data"),
    ]

    DEFAULT_CONFIG_NAME = "all"

    def _info(self):
        return datasets.DatasetInfo(
            description=_DESCRIPTION,
            features=datasets.Features({
                "context": datasets.Value("string"),
                "question": datasets.Value("string"),
                "prerequisit": datasets.Value("string"),
                "groundtruth_zoo": datasets.Sequence(datasets.Value("string")),
                "answer": datasets.Value("string"),
            }),
            supervised_keys=None,
            homepage="https://huggingface.co/datasets/JesseLiu/MedQA_Maze",
            citation=_CITATION,
        )

    def _split_generators(self, dl_manager):
        """Returns SplitGenerators."""
        config_name = self.config.name if self.config.name != "default" else "all"

        urls = {}
        if config_name == "all":
            urls = {
                "train": f"{_BASE_URL}/all/train.jsonl",
                "test": f"{_BASE_URL}/all/test.jsonl"
            }
        elif config_name in ["basic", "advance", "challenge"]:
            urls = {
                "test": f"{_BASE_URL}/{config_name}/test.jsonl"
            }
        else:
            raise ValueError(f"Unsupported config: {config_name}")

        try:
            data_files = dl_manager.download(urls)
            logger.info(f"Downloaded files: {data_files}")
        except Exception as e:
            raise ValueError(f"Failed to download files: {e}")

        splits = []
        if "train" in data_files:
            splits.append(
                datasets.SplitGenerator(
                    name=datasets.Split.TRAIN,
                    gen_kwargs={"filepath": data_files["train"]}
                )
            )
        if "test" in data_files:
            splits.append(
                datasets.SplitGenerator(
                    name=datasets.Split.TEST,
                    gen_kwargs={"filepath": data_files["test"]}
                )
            )

        if not splits:
            raise ValueError(f"No valid splits found for config {config_name}")

        return splits

    def _generate_examples(self, filepath):
        """Yields examples."""
        logger.info(f"Generating examples from {filepath}")
        
        if not os.path.exists(filepath):
            raise ValueError(f"File not found: {filepath}")
            
        with open(filepath, 'r', encoding='utf-8') as f:
            content = f.read().strip()
            # Split by newlines and filter out empty lines
            lines = [line.strip() for line in content.split('\n') if line.strip()]
            
            for idx, line in enumerate(lines):
                try:
                    data = json.loads(line)
                    example = {
                        "context": str(data.get("context", "")),
                        "question": str(data.get("question", "")),
                        "prerequisit": str(data.get("prerequisit", "")),
                        "groundtruth_zoo": [str(x) for x in data.get("groundtruth_zoo", [])],
                        "answer": str(data.get("answer", "")),
                    }
                    yield idx, example
                except json.JSONDecodeError as e:
                    logger.error(f"Error parsing JSON at line {idx} in {filepath}: {e}\nLine content: {line[:100]}...")
                    continue
                except Exception as e:
                    logger.error(f"Unexpected error processing line {idx} in {filepath}: {e}")
                    continue