# TODO Figure out how threads work
# TODO Do a Fibonacci counter

import concurrent.futures


def fib(pos, _tpe):
    """Return the Fibonacci number at position."""
    if pos < 2:
        return pos

    x = fib(pos - 1, None)
    y = fib(pos - 2, None)

    return x + y


def fibp(pos, tpe):
    """Return the Fibonacci number at position."""
    if pos < 2:
        return pos

    x = tpe.submit(fib, (pos - 1), tpe).result()
    y = tpe.submit(fib, (pos - 2), tpe).result()

    return x + y


if __name__ == '__main__':
    import sys

    with concurrent.futures.ThreadPoolExecutor() as cftpe:
        fun = fibp if len(sys.argv) is 3 else fib
        position = int(sys.argv[1])
        print(fun(position, cftpe))
        print(fun.__name__)

$ time python test_fib_parallel.py 35
9227465
fib

real    0m3.778s
user    0m3.746s
sys     0m0.017s

$ time python test_fib_parallel.py 35 dummy-var
9227465
fibp

real    0m3.776s
user    0m3.749s
sys     0m0.018s