Cafeteria App

An automated cafeteria system that allows any customer to place order from the available restaurants without human intervention. Users can get the order from the restaurant which provides it in the minimum value.
Users can check the menu from all the restaurants. Restaurants are initiated with a particular power and menu. Whenever a user places an order from the Cafeteria, the best price for that order is checked depending on the power availability of the restaurant. Once the order is placed the total power of the restaurant is reduced and once the order is delivered successfully the power is restored back to the restaurant.

Environment

• version: 1.0
• support: UNIX with Python 2.x, 3.x

Getting Started

Project structure

cafeteria/
    ├── app.py
    ├── bin
    │   ├── setup
    │   └── setup.sh
    ├── cafe.py
    ├── data.py
    ├── .travis.yml
    ├── README.md
    ├── restaurant.py
    ├── test_main.py
    └── tests
        ├── test_cafe.py
        └── test_restaurant.py

• bin directory has executables to setup and run the project.
• tests directory has unit tests for all the methods in the models, it is controlled by test_main.py file in the cafeteria directory
• restaurant.py holds the implementation of Restaurant class.
• cafe.py holds the implementation of Cafeteria class.
• Cafeteria holds has_a relationship with Restaurant class. Thus a Composite relationship logic has been used while designing them.
• test_main.py runs all the unit tests written in the tests directory.
• .travis.yml TRAVIS CI configuration file.

Installing

Once u have cloned/uncompressed project in your directory say cafeteria, change to the project directory via terminal and run the setup

$ cd cafeteria

Run setup file

$ bin/setup

This will do the necessary setup and run all the unittests.

On successful installation you should see messages similar to below:

Building Cafeteria app version 1.0
Reading package lists... Done
Building dependency tree       
Reading state information... Done
python3 is already the newest version (3.6.7-1~18.04).
python3-pip is already the newest version (9.0.1-2.3~ubuntu1.18.04.1).
0 upgraded, 0 newly installed, 0 to remove and 18 not upgraded.
--- Running automated tests for Cafeteria app ---
....Order Cost: $33 
 Cheapest Restaurant: Restaurant C
soda is not present in our menu. 
 Kindly check the menu and try again.
No items found. Please place some items in your order.
.Order Cost: $33 
 Cheapest Restaurant: Restaurant C
Your order has been placed successfully!
soda is not present in our menu. 
 Kindly check the menu and try again.
Error placing the order!
.
----------------------------------------------------------------------
Ran 6 tests in 0.001s

OK
Setup done Successfully!

NOTE- If you're running a WINDOWS machine, then just install Python and then open the app.py to run you're own test cases(shown below).

Usage

• The app.py file has been created to play around. It has most of the examples and usage covered but let's get through some of the important methods.

• To run your own test cases, you can add more cases in app.py itself or can create another python file in the same directory.

• As shown in app.py once the Cafeteria object is created the menu can be checked as:

>> cafe1 = Cafeteria()
>> cafe1.display_complete_menu()

Output:

MENU FOR RESTAURANT: A
+ WAFFLES: $9
+ DONUTS: $10
+ PASTRY: $8
+ SOUP: $6
+ BIRYANI: $22
+ COKE: $5

MENU FOR RESTAURANT: B
+ WAFFLES: $10
+ DONUTS: $11
+ PASTRY: $9
+ SOUP: $7
+ BIRYANI: $20
+ COKE: $3

MENU FOR RESTAURANT: C
+ WAFFLES: $12
+ DONUTS: $9
+ PASTRY: $10
+ SOUP: $10
+ BIRYANI: $18
+ COKE: $6

• Checking the best(lowest) price for that order

>> cafe1.check_best_price_for_order(["coke", "biryani"])

Output: 

Order Cost: $23 
Cheapest Restaurant: Restaurant B

• Placing the order

>> cafe1.place_order(["coke", "biryani"])

Output:

******* Placing your order. Please wait! ********
Order Cost: $23 
Cheapest Restaurant: Restaurant B
Your order has been placed successfully!

• You can also pass the order as string

>> cafe1.place_order("coke biryani")

Output:

******* Placing your order. Please wait! ********
Order Cost: $23
Cheapest Restaurant: Restaurant B
Your order has been placed successfully! 

• You can also pass the order as tuple

>> cafe1.place_order("waffles", "donuts")

Output:

******* Placing your order. Please wait! ********
Order Cost: $19
Cheapest Restaurant: Restaurant A
Your order has been placed successfully! 

• Placing an order which is not in the menu

>> cafe1.place_order(["donuts", "sdfd", "soup", "biryani"])

Output:

******* Placing your order. Please wait! ********
sdfd is not present in our menu. 
Kindly check the menu and try again.
Error placing the order!

• Placing an empty order

>> cafe1.place_order([])

Output:

******* Placing your order. Please wait! ********
No items found. Please place some items in your order.
Error placing the order!

• Placing order with value more than a restaurant's power

>> cafe1.place_order(["coke", "biryani", "coke", "biryani", "coke", "biryani", "coke", "biryani"])

Output:

******* Placing your order. Please wait! ********
Can't place order! Restaurants busy, please visit in sometime.
Error placing the order!

• Placing an order with ambiguous data types

>> cafe1.place_order(12)

Output:

******* Placing your order. Please wait! ********
Error placing the order!

NOTE- These commands should be executed in a python file with Cafeteria object initialized. As shown in app.py file.

Extras

• running the tests. In your terminal type

$ python test_main.py

• adding more restaurants/power/items: make changes in the data.py file. In case you are adding restaurants, do the necessary changes in __init__ method of cafe.py file. Given example for change in cafe.py after adding a restaurant(let's say D).

def __init__(self):
    .    
    .
    .

    self.item_costs_D = data.items_price_restaurant_D
    self.power_D = data.power_D
    self.restaurant_D = Restaurant(self.power_D, self.item_costs_D)

    self.restaurants = {"A": self.restaurant_A, "B": self.restaurant_B,
                         "C": self.restaurant_C, "D": self.restaurant_D}

• currently the power consumption(while placing an order) and restoring the power(once order is successfully completed) goes together(check place_order method in cafe.py) but any logic to lapse the time in between can be added. For example one can add a timestamp with each order and after that timestamp only the power would be restored.

Code Time Complexity

Assuming there are M restaurants in the cafeteria with each having N items. And the items in an order placed by the user is Z. Big O Complexity for various operations are given.

• display_complete_menu() : O(M*N) Time

• check_best_price_for_order() : O(M*Z) (for each restaurant calculates the price using the dictionary)

• place_order() : O(M*Z)

Author

• Abhinav Anand - ab-anand