Calculate the ratio from System bricks/plates to Technic holes.

plate_ratio.py

from __future__ import print_function
from sys import exit
from math import floor

from nose.tools import assert_equals

__author__ = "Andy Burton"


PLATES_IN_BRICK = 3

PLATE_TO_HOLE_RATIO_DICT = {
    'plate': 5,
    'hole': 2,
}

PLATE_TO_HOLE_MIN_DICT = {
    'plate': 2,
    'hole': 1,
}


def bricks_and_plates(plates):
    """ Convert a number of plates into the total number of bricks and plates remainder. """
    if plates < PLATES_IN_BRICK:
        return 0, plates
    else:
        bricks = int(floor(plates / PLATES_IN_BRICK))
        plates_remainder = plates % PLATES_IN_BRICK
        return bricks, plates_remainder


def increase_numbers(current_numbers_dict):
    """ Increment by one ratio set. """
    new_hole_amt = current_numbers_dict['hole'] + PLATE_TO_HOLE_RATIO_DICT['hole']
    new_plate_amt = current_numbers_dict['plate'] + PLATE_TO_HOLE_RATIO_DICT['plate']
    return {
        'hole': new_hole_amt,
        'plate': new_plate_amt,
    }


def decrease_numbers(current_numbers_dict):
    """ Decrease by one ratio set. Cannot go below the minimum ratio. """
    new_hole_amt = current_numbers_dict['hole'] - PLATE_TO_HOLE_RATIO_DICT['hole']
    new_plate_amt = current_numbers_dict['plate'] - PLATE_TO_HOLE_RATIO_DICT['plate']
    if new_hole_amt < PLATE_TO_HOLE_MIN_DICT['hole']:
        return PLATE_TO_HOLE_MIN_DICT
    else:
        return {
            'hole': new_hole_amt,
            'plate': new_plate_amt,
        }


def display_text(current_numbers_dict):
    """ Display according to what types of pieces you need. """
    bricks, plates = bricks_and_plates(current_numbers_dict['plate'])
    if bricks > 0:
        return "The smalled ratio you can have is {0} bricks and {1} plates to {2} Technic holes.".\
            format(bricks, plates, current_numbers_dict['hole'])
    else:
        return "The smalled ratio you can have is {0} plates to {1} Technic holes.". \
            format(plates, current_numbers_dict['hole'])


def byebye(*args, **kwargs):
    print("Good bye!")
    exit()


def run_tests():
    """ Run tests when starting up to verify everyting works as expected. """
    try:
        # Test that the three plates always equals one brick plus the remaider of plates
        assert_equals(bricks_and_plates(1), (0, 1))
        assert_equals(bricks_and_plates(3), (1, 0))
        assert_equals(bricks_and_plates(4), (1, 1))
        # Test that decreasing the ratio does not go below the base ratio
        test_ratio_dict = PLATE_TO_HOLE_MIN_DICT
        assert_equals(decrease_numbers(test_ratio_dict), PLATE_TO_HOLE_MIN_DICT)
        # Test that increasing the ratio returns what we expect
        # Smallest set
        assert_equals(test_ratio_dict, PLATE_TO_HOLE_MIN_DICT)
        # Up one
        test_ratio_dict = increase_numbers(test_ratio_dict)
        assert_equals(test_ratio_dict, {'hole': 3, 'plate': 7})
        # One more
        test_ratio_dict = increase_numbers(test_ratio_dict)
        assert_equals(test_ratio_dict, {'hole': 5, 'plate': 12})
    except Exception as ex:
        raise ex


# These are the available actions.
ACTIONS_LIST = {
    'I': increase_numbers,
    'D': decrease_numbers,
    'E': byebye,
}


if __name__ == '__main__':
    input_text = "What is your choice? (I)ncrease, (D)ecrease, (E)xit: "
    current_ratio_dict = PLATE_TO_HOLE_MIN_DICT

    run_tests()

    # Main loop to allow user to view ratio amounts.
    # TODO: Increase or decrease by amount. Create parser to look for second parameter.
    while True:
        print(display_text(current_ratio_dict))
        action_to_take = raw_input(input_text).upper()
        action_func = ACTIONS_LIST[action_to_take if ACTIONS_LIST.has_key(action_to_take) else 'E']
        current_ratio_dict = action_func(current_ratio_dict)