builder.py

from enum import Enum
import time

PizzaProgress = Enum('PizzaProgress', 'queued preparation baking ready')
PizzaDough = Enum('PizzaDough', 'thin thick')
PizzaSauce = Enum('PizzaSauce', 'tomato creme_fraiche')
PizzaTopping = Enum('PizzaTopping', 
                    'mozzarella double_mozzarella bacon ham mushrooms red_onion oregano')
STEP_DELAY = 3 # in seconds for the sake of the example


class Pizza:
    def __init__(self, name):
        self.name = name
        self.dough = None
        self.sauce = None
        self.topping = []

    def __str__(self):
        return self.name

    def prepare_dough(self, dough):
        self.dough = dough
        print(f'preparing the {self.dough.name} dough of your {self}...')
        time.sleep(STEP_DELAY)
        print(f'done with the {self.dough.name} dough')

        
class MargaritaBuilder:
    def __init__(self):
        self.pizza = Pizza('margarita')
        self.progress = PizzaProgress.queued
        self.baking_time = 5 # in seconds for the sake of the example

    def prepare_dough(self):
        self.progress = PizzaProgress.preparation
        self.pizza.prepare_dough(PizzaDough.thin)

    def add_sauce(self):
        print('adding the tomato sauce to your margarita...')
        self.pizza.sauce = PizzaSauce.tomato
        time.sleep(STEP_DELAY)
        print('done with the tomato sauce')

    def add_topping(self):
        topping_desc = 'double mozzarella, oregano'
        topping_items = (PizzaTopping.double_mozzarella, PizzaTopping.oregano)
        print(f'adding the topping ({topping_desc}) to your margarita')
        self.pizza.topping.append([t for t in topping_items])
        time.sleep(STEP_DELAY)
        print(f'done with the topping ({topping_desc})')

    def bake(self):
        self.progress = PizzaProgress.baking
        print(f'baking your margarita for {self.baking_time} seconds')
        time.sleep(self.baking_time)
        self.progress = PizzaProgress.ready
        print('your margarita is ready')

        
class CreamyBaconBuilder:
    def __init__(self):
        self.pizza = Pizza('creamy bacon')
        self.progress = PizzaProgress.queued
        self.baking_time = 7 # in seconds for the sake of the example

    def prepare_dough(self):
        self.progress = PizzaProgress.preparation
        self.pizza.prepare_dough(PizzaDough.thick)

    def add_sauce(self):
        print('adding the crème fraîche sauce to your creamy bacon')
        self.pizza.sauce = PizzaSauce.creme_fraiche
        time.sleep(STEP_DELAY)
        print('done with the crème fraîche sauce')

    def add_topping(self):
        topping_desc = 'mozzarella, bacon, ham, mushrooms, red onion, oregano'
        topping_items =  (PizzaTopping.mozzarella,
                          PizzaTopping.bacon,
                          PizzaTopping.ham,
                          PizzaTopping.mushrooms,
                          PizzaTopping.red_onion, 
                          PizzaTopping.oregano)
        print(f'adding the topping ({topping_desc}) to your creamy bacon')
        self.pizza.topping.append([t for t in topping_items])
        time.sleep(STEP_DELAY)
        print(f'done with the topping ({topping_desc})')

    def bake(self):
        self.progress = PizzaProgress.baking
        print(f'baking your creamy bacon for {self.baking_time} seconds')
        time.sleep(self.baking_time)
        self.progress = PizzaProgress.ready
        print('your creamy bacon is ready')

        
class Waiter:
    def __init__(self):
        self.builder = None

    def construct_pizza(self, builder):
        self.builder = builder
        steps = (builder.prepare_dough, 
                 builder.add_sauce, 
                 builder.add_topping, 
                 builder.bake)
        [step() for step in steps]

    @property
    def pizza(self):
        return self.builder.pizza

        
def validate_style(builders):
    try:
        input_msg = 'What pizza would you like, [m]argarita or [c]reamy bacon? '
        pizza_style = input(input_msg)
        builder = builders[pizza_style]()
        valid_input = True
    except KeyError:
        error_msg = 'Sorry, only margarita (key m) and creamy bacon (key c) are available'
        print(error_msg)
        return (False, None)
    return (True, builder)

    
def main():
    builders = dict(m=MargaritaBuilder, c=CreamyBaconBuilder)
    valid_input = False
    while not valid_input:
        valid_input, builder = validate_style(builders)
    print()
    waiter = Waiter()
    waiter.construct_pizza(builder)
    pizza = waiter.pizza
    print()
    print(f'Enjoy your {pizza}!')

    
if __name__ == '__main__':
    main()