from typing import List, Tuple


class DataImporter( object ):
    """
    An abstract data importer.

    Instanciate concrete instances via the Importer() function
    """

    def retrieve( self ) -> List[str]:
        """
        Retrieve a list of transactions
        """
        return []

from .mock import MockDataImporter
from .modo import ModoDataImporter

#-------------------------------------------------------------------------------

def verify( config: dict, path: str = "" ) -> Tuple[bool, List[str]]:
    """
    Verifies that the configuration is correct

    Args:
        config: dict with password manager configuration
        path: path to the "config" dict in the main configuration file

    Returns:
        bool: true if the config is correct
        List[str]: list of errors if the config is not correct
    """
    if "import" not in config:
        return (False, [f'Missing "{path}.import" value'])
    if "name" not in config:
        return (False, [f'Missing "{path}.name" value'])

    importer = config["import"]
    for cls in DataImporter.__subclasses__():
        if importer == cls.name():
            return cls.verify(config, path)
    return (False, [f'Unknown data importer "{importer}"'])

#-------------------------------------------------------------------------------

def Importer( config: dict ) -> DataImporter:
    """
    Instanciate an Importer instance from a given configuration
    """
    if "import" not in config:
        raise ValueError
    if "name" not in config:
        raise ValueError
    importer = config["import"]
    for cls in DataImporter.__subclasses__():
        if importer == cls.name():
            return cls(config)
    raise ValueError