ii.      Independently solve a problem by using programming concepts taught over the duration of the course;

iii.     Write and debug Python code independently;

iv.      Document code;

v.      Provide references where due;

vi.      Meet deadlines;

vii.      Seek clarification from your "supervisor" (instructor) when needed via the Canvas discussion forums; and

viii.      Create a program by recalling concepts taught in class, understand and apply concepts

relevant to solution, analyse components of the problem, evaluate different approaches.

3. Learning Outcomes

This assignment is relevant to the following Learning Outcomes:

1.   Analyse simple computing problems.

2.   Devise suitable algorithmic solutions and code these algorithmic solutions in a computer programming language.

3.   Develop maintainable and reusable solutions.

Specifically, upon the completion of this assignment, you will be able to:

•   Demonstrate knowledge of basic concepts, syntax and control structures in programming

•   Devise solutions for simple computing problems under specific requirements

•   Encode the devised solutions into computer programs and test the programs on a computer

•   Demonstrate understanding of standard coding conventions and ethical considerations in programming

4. Assessment Details

Please ensure that you have read Sections 1-3 of this document before going further.

Requirements: Your code must meet the following functionalities, code and documentation requirements. Your submission will be graded based on the rubric published on Canvas. Please  ensure you read all the requirements and the rubric carefully before working on your assignment.

A - Functionalities Requirements:

There are 4 levels, please ensure you only attempt one level after completing the previous level.

------------------------------------------- PASS Level (12 marks) ------------------------------------------

At this level, your program will have some basic classes with specifications as below. You may need to define methods wherever appropriate to support these classes. At the end of the PASS level, your  program should be able to run with a menu described in the Operations.

Customers:

1. Class Customer

All customers have a unique ID, unique name (a name will not include any digit). You are required to write the class named Customer to support the following:

i.      Attributes ID and name

ii.     Attribute value to store the total money the customer spent to date. A new customer will have the value of value to be 0 before placing any order.

iii.      Constructor takes the values of ID, name, value as arguments

iv.      Appropriate getter methods for the attributes of this class

v.      A method get_discount(self, price) which returns (0, price) – where the first return    value represents the discount rate associated with the customer and the second value   represents the input price. This method serves as a super method and will have a more complex implementation in the subclasses.

vi.      A method display_info that prints the values of the Customer attributes and the discount rate associated with the customer.

2. Class Member

A member is a customer with a membership. When placing an order, a member will be        offered a discount. All members are offered a discount of a flat rate (i.e., the discount rate is the same for all orders – this is to distinguish from the discount of VIPMember below). The class Member should have the following components:

i.  An attribute for discount rate, by default, it is 5%.

ii.  Constructor takes the appropriate parameters/arguments (be careful)

iii.  Appropriate getter methods for the attributes of this class

iv.  A method get_discount(self, price) that takes the price of the order and returns both the discount rate and the price after the discount. For example, this method returns   (0.05, 950) when the discount rate is 5% and the order's price is 1000$.

v.  A method display_info(self) that prints the values of the Member attributes.

vi.  A method set_rate to adjust the flat rate of discount. This affects all members.

3. Class VIPMember

A VIP member is a customer with a VIP membership. All VIP members are offered a             discount based on two rates: the first rate applies when the price of the order is smaller or       equal to a threshold ($1000 by default), and the second rate applies when the order's price      exceeds this threshold. For example, with the threshold being 1000$, then, when a VIP           member named Sarah places an order that costs 800$, the discount rate for this order is the 1st discount rate; when Sarah places an order that costs 1200$, the discount rate for this order is  the 2nd discount rate.

NOTE for all VIP members, the 2nd discount rate is always 5% more than the 1st discount     rate. The discount rates might be different among the VIP members. If not specified, the first and second discount rates are set as 10% and 15%, respectively. On the other hand, the         threshold applies to all VIP members, i.e., all VIP members have the same threshold.

The class VIPMember should support the following components

i.     Attributes to support the two discount rates and the threshold limit

ii.    Necessary constructors

iii.   Appropriate getter methods for the attributes of this class

iv.   A method get_discount(self, price) that takes the price of the order and returns both the discount rate and the price after the discount.

v.    A method display_info that prints the values of the VIPMember attributes.

vi.   A method set_rate to adjust the discount rates of each individual VIP member.

vii.  A method set_threshold to adjust the threshold limit. This affects all VIP members.

Products

4. Class Product

This class is to keep track of information on different products that the department store sells. This class supports the following information:

• ID: A unique identifier of the product (e.g., P1, P2, P3)

• Name: The name of the products (you can assume the product names are unique and they do not include any digit)

• Price: The price of the product

• Stock: the quantity of the product available in stock

You need to define appropriate attributes and methods to support the class Product. Note the stock quantity obviously will be changed. The product's price may also be changed by users.

Orders

5. Class Order

This class is to handle customers' orders. This class supports the following information of an order:

• Customer: the one who place the order (can be a normal customer, a customer with a

normal membership, or a customer with a VIP membership). Note you need to think/analyse if this should be an ID, name, or something else.

• Product: the product of the order. Note you need to think/analyse if this should be an ID, name, or something else.

• Quantity: the quantity of the product ordered by customers.

•   You need to think if there are any extra attributes and methods you want to define in this class

Note that this class can update information in the corresponding customer and destination if necessary. For example, an object from the class Order can update the information of the     corresponding customer (e.g., discount rate) or/and the product (e.g., stock). Therefore, you need to define appropriate variables and methods to support this class.

Records

6. Class Records

This class is the central data repository of your program. It supports the following information:

• A list of existing customers – you need to think what you should store in this list (ID, name, or something else?)

• A list of existing products – you need to think about what you should store in this list (ID, name, or something else?)

•   This class has a method named read_customers that can read a comma-separated file called customers.txt and add the customers in this file to the customer list of the class. See an example of the customers.txt file below.

In this file, customers are always in this format: ID, name, discount rate, and value.    For example, in the 1st line, the ID is C1, the name is James, the discount rate of this   customer is 0, and the value is 500.2. Note that for VIP members, the first discount     rates will be stored. A normal customer has an ID starting with the letter "C". A           member (customer with a normal membership) has an ID starting with the letter "M". A VIP member (customer with a VIP membership) has an ID starting with the letter "V". The numbers in the ID after these characters (C, M, V) are all unique (i.e., 1, 2,   3, 5… are unique; for example, if there is a customer with the ID of C1, there won't be a member with the ID of M1). In this part, you can assume there will be no error in     this customers.txt file (e.g., the data format is always correct, and the values are           always valid).

•   This class has another method named read_products that can read another comma- separated value file called products.txt and add the products stored in that file to the product list of the class. See an example of the products.txt file below.

In this file, products are always in this format: ID, name, price (unit price per each      product), and the stock. The IDs of all products always start with the letter "P". All     the product IDs are unique. You can assume there will be no error in this file (e.g., the data format is always correct, and the values are always valid).

•   This class also has two methods find_customer and find_product. These two           methods are to search through the list of customers and products to find out whether a given customer or a given product exists or not. If found, the corresponding customer and product will be returned, otherwise, None will be returned. Note that both the       customer and the product can be searched using either ID or name.

•   This class also has two methods list_customers and list_products. These two             methods can list all the existing customers and products on screen. The display format is flexible, and note that you can display all necessary information, and make sure at   least all the information as in the customers.txt and products.txt files should be            displayed. These methods can be used to validate the reading from the .txt files customers.txt and products.txt.

NOTE you are allowed to add extra attributes and methods in this class if these attributes and methods make your program more efficient.

Operations

This can be considered the main class of your program. It supports a menu with the following options:

i. Place an order: this option allows users to place an order for a customer. Detailed requirements for this option are below (Requirements vi-viii).

ii. Display existing customers: this option can display all the information: ID, name, discount rate (1st discount rate for VIP member), value, threshold limit (for VIP member) of all       existing customers.

iii. Display existing products: this option can display all the information: ID, name, price, stock of all existing products.

iv. Exit the program: this option allows users to exit the program.

Other requirements of the menu program are as follows:

v.      When the program starts, it looks for the files customers.txt and products.txt in the local         directory (the directory that stores the .py file of the program). If found, the data will be read  into the program accordingly, the program will then display a menu with the 4 options            described above. If any file is missing, the program will quit gracefully with an error message indicating the corresponding file is missing.

vi.      Your menu program will allow the user to place an order as specified in PART 1 of               Assignment 1. Note that in this assignment, the customer can choose to get a normal              membership or a VIP membership (a VIP membership will cost 200$ more). More detailed   information regarding the membership choice is in section vii below. Also, note that you do  not need to handle errors in input in this part. For example, similar to PART 1 of Assignment 1, you can assume users always enter valid products, valid product prices, and valid "y" or "n" answers. You can also assume users always enter the membership type correctly, for       example, "M" for a normal membership, and "V" for a VIP membership.

vii.     When a customer finishes placing an order,

a.   If the customer is a new customer, you need to add the information of that customer   into your data collection (think/analyse carefully which information you need to add  to your data collection). If the customer answers "n" for the question of becoming a    member, then the customer is just a normal customer. If the customer answers "y",     then the program will ask what type of member the customer wants. If the answer is "M", then the customer will become a member (a customer with a normal                    membership). If the answer is "V", then the customer will become a VIP member (a   customer with a VIP membership). Note that the customer will need to pay an extra   200$ for becoming a VIP member. Discount is NOT applied to this 200$ membership fee. Again, you can assume the users enter the membership type correctly ("M" or      "V").

b.   If the customer is an existing customer, you need to update the information of that     customer in your data collection (think/analyse carefully which information you need to update). Note, for existing customers, you DO NOT need to ask if they want a       membership (normal or VIP membership). This is slightly different compared to the  requirements in Assignment 1, so please be careful.

c.   Note that, be careful when you add a new customer to your data collection. As       mentioned in the description of the class Customer, both the ID and the name of a customer are unique.

d.   The value of the customer will be increased by the total money they spent on the order (this includes the VIP membership fee).

e.   After each order, the stock of the chosen product will be reduced by the quantity in the order. At this level, you do not need to handle errors when the quantity in the   order is larger than the stock quantity.

viii.      The total cost of an order can be displayed as a formatted message as below (for existing

customers, new customers who are normal customers, or customers with normal membership):

<customer name > purchases x .

Unit price: price of the product> (AUD)

<customer name> gets a discount of percentage>%.

Total price: total price> (AUD)

The formatted message is as below for new customers who register to be VIP members:

<customer name > purchases x .

Unit price: price of the product> (AUD)

Membership price: <the price of VIP membership> (AUD)

<customer name> gets a discount of percentage>%.

Total price: total price> (AUD)

ix.      When a task is accomplished, the menu will appear again for the next task. The program always exits gracefully from the menu.

---------- CREDIT level (3 marks, please do not attempt this level before completing

the PASS level) ------------

At this level, you need to handle exceptions compared to the PASS level. At this level, you are required to define various custom exceptions to handle the below issues:

i.      Display an error message if the product entered by the user does not exist in the product list.  When this error occurs, the user will be given another chance, until a valid product is entered.

ii.      Display an error message if the product quantity is 0, negative, not an integer, or larger than the stock quantity of the product. When this error occurs, the user will be given another       chance, until a valid product quantity is entered.

iii.      Display an error message if the answer by the user is not y or n when asking if the customer wants a membership. When this error occurs, the user will be given another chance, until a  valid answer (i.e., y, n) is entered.

iv.      Display an error message if the answer by the user is not M or V when asking the membership type. When this error occurs, the user will be given another chance, until a valid answer (i.e., M, V) is entered.

v.      Display an error message if there are any errors in the files customers.txt, products.txt, e.g.,   wrong data format, invalid customer IDs, etc. When an error occurs, the program will display a message indicating something wrong with the files, and then exit.

Operations

i.      In this level, in the "Place an order" option, your program will allow ordering a Bundle,

which is a special product. It means multiple products can be offered together as one product. For example, a bundle can consist of an oven, a kettle, and a microwave. You can assume all parts of a bundle are existing products in the system.

The price of a bundle is 80% of the total price of all individual products. For example, if an oven costs 300$, a kettle costs 80$, pot costs 30$, and glass costs 15$, then the price of this bundle is 80% x (300 + 80 + 30 + 15) = 340$.

To support this feature, you need to add one more class (Bundle) to your program.

7. Class Bundle: Each bundle has a unique ID and name (as with Product). You need to

define the appropriate attributes and methods to support the class Bundle.    With this modification, the CSV file products.txt at this level may look like this:

The ID of a Bundle always starts with the letter "B". Note that the data format of a bundle is  different compared to a normal product; it includes the IDs of the product components, and at the end, it includes the stock quantity of the bundle. The IDs/names of the products and          bundles are all unique. You can assume all the products in a bundle are existing products and unique (no duplicates). You can assume bundles are always stored at the end of a file, after    all normal products.

ii.     Also, at this level, your program should display an error message if the product price is not set, 0, or negative when the user tries to order it. If this error occurs, your program will then go back to the main menu. You can assume the product prices in the products.txt file are     always either empty or are valid numbers.

iii.     At this level, for the option "Display existing products", when displaying bundles, your     program will display the ID, name, the IDs of the components, and the stock. On the other hand, the products information is the same as in the PASS level.

iv.      Finally, your program should support both products' IDs and names when placing an order. For example, instead of entering the product names like in the PASS level, now, users can  enter the product IDs when placing an order.

---------- DI Level (3 marks, please do not attempt this part before completing the

CREDIT level) -----------

In this part, there are some additional main features for some classes in your program. Some features might be challenging. Details of these features are described as follows.

Class Order: This class now supports date information, i.e., it now has an attribute name date that stores which date and time the order are made (you can use an external Python module for this       feature).

Operations

Your program now can:

i.     Automatically load previous orders that are stored in a comma-separated file named

orders.txt that is located in the local directory (same directory with the .py file). Below is an example of the orders.txt file:

Each line in the file is an order. The format is always customer name, product, product quantity, and date. You can assume all the customers in the orders.txt are existing customers (their names are inside the customers.txt file). You can assume all the products in the orders.txt are existing products (their names/IDs are inside the products.txt file). Both            customers and products can be referred by IDs or by names in this orders.txt file. You can     assume all other information (product quantity, date) in this orders.txt file is always valid.

ii.      Errors when loading the orders.txt file should also be handled. When there are any errors       loading the file, your program will print a message saying "Cannot load the orderfile. Run as if there is no order previously." and run as if there is no order previously.

iii.     Your menu program should have an option "Adjust the discount rates of a VIP member" to     adjust the discount rates of the VIP members. The option will ask for the name or ID of the    VIP member, then ask for the new first discount rate (the second discount rate will then be     adjusted accordingly). Invalid customers (non-existent or non-VIP customers) will cause the  program to print a message saying: "Invalid customer!", and then go back to the main menu.  Invalid discount rate inputs (non-number or negative discount rates) should be handled via     exceptions, and the user will be given another chance until a valid input is entered. Also, your program should support both customers' IDs and names in this option, i.e., users can type       either customer name or customer ID.

iv.     Your menu program should have an option "Adjust the threshold limit of all VIP members" to adjust the threshold limit of all the VIP members. This adjustment will affect all VIP

members in all future orders. Invalid threshold inputs (non-number of 0 or negative          threshold) should be handled via exceptions; the user will be given another chance until a valid input is entered.

v.      Your menu program should have an option "Display all orders" to display all previous  orders. The formatted message should be similar to in the orders.txt file (can be slightly different but all the information as in the orders.txt file should be shown).

vi.     Your menu program should have an option "Display all orders of a customer" to display all   previous orders of a particular customer. Users can pass in the name or ID of a customer. The formatted message is similar to the previous requirement on the option "Display all orders".  Note if the name or the ID of the customer is invalid, your program should print a message    saying: "Invalid customer!", then go back to the main menu.

vii.     Note, in this part, you need to analyse the requirements and update some classes so that your program can satisfy the requirements listed above .