import pandas as pd
import os


class DataLoader:

    @staticmethod
    def load(filepath: str, index_col: str = None) -> pd.DataFrame:
        """
        Load different datasets
        """

        if not os.path.exists(filepath):
            raise FileNotFoundError(f"File not found: {filepath}")

        if filepath.endswith('.parquet'):
            df = pd.read_parquet(filepath)
            if index_col is not None:
                df = df.set_index(index_col)
        elif filepath.endswith('.csv'):
            df = pd.read_csv(filepath, index_col=index_col)
        else:
            raise ValueError(f"File format not supported for file: {filepath}")

        return df