import all_constants as c


def convert_distance(value, from_unit, to_unit):
    """
    Converts a distance value from one unit to another.
    Uses meters as the intermediate base unit.
    Returns the result rounded to 4 decimal places (or int if whole number).
    """
    # Convert to meters first, then to target unit
    in_meters = value * c.TO_METERS[from_unit]
    result = in_meters / c.TO_METERS[to_unit]

    # Round to 4 decimal places and strip trailing zeros
    rounded = round(result, 4)
    if rounded == int(rounded):
        return int(rounded)
    return rounded