from contextlib import contextmanager
import pandas as pd

class DataService(object):
  @contextmanager
  def build(self):
    data_service = None
    try:
      data_service = DefaultDataService()
      yield data_service
    finally:
      if data_service: data_service.close()

  def close(self):
    raise Exception("Should not use the base class")

  def get_patients(self) -> list[str]:
    raise Exception("Should not use the base class")

class DefaultDataService(DataService):

  def __init__(self):
    self._dataset_url = "https://huggingface.co/datasets/iscg34/finalproject/raw/main/patient_encounters1_notes.csv"
    self._initialized = False

  def initialize(func):
    def wrapper(self):
      if not self._initialized:
        self._df = pd.read_csv(self._dataset_url)
        self._initialized = True
      return func(self)

    return wrapper

  def close(self):
    #raise Exception("Not implemented")
    pass

  @initialize
  def get_patients(self) -> list[str]:
    col = self._df["FIRST"]
    u = col.unique()
    l = u.tolist()
    return l