from datetime import datetime
from fn.func import curried


def datetime_range(start, end, delta, dt_format='%Y-%m-%d %H:%M:%S'):
    reverse_head = end
    [start, end] = [datetime.strptime(x, dt_format) for x in [start, end]]

    def _datetime_range(start, end, delta):
        current = start
        while current < end:
            yield current
            current += delta

    reverse_tail = [dt.strftime(dt_format) for dt in _datetime_range(start, end, delta)]
    return reverse_tail + [reverse_head]


def last_index(l):
    return len(l)-1


def retrieve_state(l, offset):
    return l[last_index(l) + offset + 1]


# exception_function = f(m_step, sL, sL[-2], _input)
# try_function = f(m_step, sL, last_mut_obj, _input)
@curried
def engine_exception(ErrorType, error_message, exception_function, try_function):
    try:
        return try_function
    except ErrorType:
        print(error_message)
        return exception_function


@curried
def fit_param(param, x):
    return x + param

# fit_param = lambda param: lambda x: x + param