from abc import (ABCMeta, abstractmethod, )
import datetime


class AbstractConnectionClient(metaclass=ABCMeta):
    """
    Clients for connections in this application will be based on this class
    """

    @abstractmethod
    def __init__(self, credentials):
        """
        Make a connection to the network and returns a client for accessing
        data.

        Arguments:
            credentials {json} -- credentials needed by the client to connect
        """
        self.credentials = credentials

    @abstractmethod
    def get_transactions(self, start_datetime, end_datetime):
        """Pulls a list of all transactions available between start and end
        times.

        Arguments:
            start_datetime {datetime} -- datetime representing start time
            end_datetime {datetime} -- datetime representing end time
        """