Expensable CLI

Taking control over your personal finance is an important skill to develop. In today's reality, don't have any debt is the holy grail of many grown-ups. That's why so many expenses-tracker apps exist in the market. Here comes Expensable 🎉

Expensable is an expense/income tracker app that exposes an API to allow the developer to freely build their own interfaces to interact with the app data. Every user has their own account protected by email and password. Expensable API gives you an authorization token to validate every request after creating a new user o login back to the application. Each user has many expense/income categories, and each category has many transactions. You can perform CRUD operations over your categories and transactions.

Your team has the job to develop a Command-Line expense/tracker application using the Expensable API. Here is the list of the application features:

Start the program

When started, your program should display the welcome message and main menu.

$ ruby expensable.rb
####################################
#       Welcome to Expensable      #
####################################
login | create_user | exit
>

• When an invalid option is typed the error message is: "Invalid option"

####################################
#       Welcome to Expensable      #
####################################
login | create_user | exit
> something
Invalid option
> 

Create a user

When the option create_user is typed, your program should ask for the user data. Then it should create the user making a post request to the API with the user data. If the response is successful, the program should display "Welcome to Expensable [first_name] [last_name]" followed by the categories page. The categories page display a table with all the categories of the type expense show the transactions of the current month, and the categories menu (later you can toggle this to see the income categories). A newly created user doesn't have any categories yet, that's why the table is empty.

> create_user
Email: john@mail.com
Password: 123456
First name: John
Last name: Doe
Phone: 987654321
Welcome to Expensable John Doe
+----+----------+-------+
|       Expenses        |
|     December 2021     |
+----+----------+-------+
| ID | Category | Total |
+----+----------+-------+
+----+----------+-------+
create | show ID | update ID | delete ID
add-to ID | toggle | next | prev | logout
>

• email: Required. Email format. Error message "Invalid format"
• password: Required. Minimum length 6. Error message "Minimum 6 characters"
• first_name: optional last_name: optional phone: optional. If supplied it should match 987654321 or +51 987654321. Error message: "Required format: +51 111222333 or 111222333"

Logout

Typing logout should perform the logout request to the API and return to the main page.

> logout
####################################
#       Welcome to Expensable      #
####################################
login | create_user | exit
>

Login (and show categories page)

If you have created a user previously, you can log in by typing the option login. The program should ask for the login data (username and password) and then make the login request to the API. If the response is successful, the program should display "Welcome back [first_name] [last_name]" followed by the categories page.

• Every student has a test user to experiment with.
• username: test[number]@mail.com
• password: 123456

We will use the user test0@mail.com from now on. This user has already some categories and transactions. To populate the categories table, your program should make a get request to the API asking for all the categories and store the response on an internal variable.

In this case, the has 6 categories of type expense. For December 2021, the sum of all the transactions amounts (values) is displayed on the Total column. This should be calculated by your program since the API doesn't store this value.

> login
Email: test0@mail.com
Password: 123456
Welcome back Test User
+----+----------------+-------+
|          Expenses           |
|        December 2021        |
+----+----------------+-------+
| ID | Category       | Total |
+----+----------------+-------+
| 3  | Food           | 206   |
| 4  | Transportation | 72    |
| 5  | Utilities      | 30    |
| 6  | Education      | 520   |
| 7  | Entertainment  | 25    |
| 8  | Other          | 220   |
+----+----------------+-------+
create | show ID | update ID | delete ID
add-to ID | toggle | next | prev | logout
>

• email: Required. Error message "Cannot be blank"
• password: Required. Error message "Cannot be blank"
• If the API response is not successful, use the response body message: "Incorrect email or password"

> login
Email: wrong@mail.com
Password: wrongpassword
Incorrect email or password
####################################
#       Welcome to Expensable      #
####################################
login | create_user | exit
>

Create category

When the option create is typed, the program asks for the category data (name and transaction_type). With that, it creates the category making a post request to the API. If the response is successful, the program will add the newly created category to the internal variable and display the table again. The new category should appear with 0 on the total column since it doesn't have any transactions yet.

> create
Name: New Category
Transaction type: expense
+-----+----------------+-------+
|           Expenses           |
|        November 2020         |
+-----+----------------+-------+
| ID  | Category       | Total |
+-----+----------------+-------+
| 3   | Food           | 206   |
| 4   | Transportation | 72    |
| 5   | Utilities      | 30    |
| 6   | Education      | 520   |
| 7   | Entertainment  | 25    |
| 8   | Other          | 220   |
| 113 | New Category   | 0     |
+-----+----------------+-------+
create | show ID | update ID | delete ID
add-to ID | toggle | next | prev | logout
>

• name: Required. Error message "Cannot be blank"
• transaction_type: Required. Only "expense" or "income". Error message "Only income or expense"

Update Category

The user can update a category by typing update [Category ID]. The program will ask for the new data and make a patch request to the API. If everything goes fine, the program should update its internal record and display the table showing the updated information.

> update 113
Name: New Expense
Transaction type: expense
+-----+----------------+-------+
|           Expenses           |
|        November 2020         |
+-----+----------------+-------+
| ID  | Category       | Total |
+-----+----------------+-------+
| 3   | Food           | 206   |
| 4   | Transportation | 72    |
| 5   | Utilities      | 30    |
| 6   | Education      | 520   |
| 7   | Entertainment  | 25    |
| 8   | Other          | 220   |
| 113 | New Expense    | 0     |
+-----+----------------+-------+
create | show ID | update ID | delete ID
add-to ID | toggle | next | prev | logout
>

• name: Required. Error message "Cannot be blank"
• transaction_type: Required. Only "expense" or "income". Error message "Only income or expense"

Delete Category

When the option delete [Category ID] is typed with a valid category ID, the program will make a delete request to the API using the ID. If the response is successful, it will remove the record from the internal variable and display the table again.

> delete 113
+----+----------------+-------+
|          Expenses           |
|        November 2020        |
+----+----------------+-------+
| ID | Category       | Total |
+----+----------------+-------+
| 3  | Food           | 206   |
| 4  | Transportation | 72    |
| 5  | Utilities      | 30    |
| 6  | Education      | 520   |
| 7  | Entertainment  | 25    |
| 8  | Other          | 220   |
+----+----------------+-------+
create | show ID | update ID | delete ID
add-to ID | toggle | next | prev | logout

• If no ID or an invalid ID is provided, the error message should be: "Not Found"

Toggle (between expenses and income)

With the option toggle, your program should change the transaction types back and forth between Expense and Income. It could have some type of flag variable to keep track of which transactions to show at any time.

> toggle
+----+-------------+-------+
|          Income          |
|      December 2020       |
+----+-------------+-------+
| ID | Category    | Total |
+----+-------------+-------+
| 1  | Salary      | 0     |
| 2  | Independent | 800   |
+----+-------------+-------+
create | show ID | update ID | delete ID
add-to ID | toggle | next | prev | logout
> 

Prev and Next (previous and next month)

The prev and next option allows the user to navigate through the calendar months. The program could have another flag variable to keep track of which month it should display at any time. (by default that variable should be initialize with the current month)

> prev
+----+-------------+-------+
|          Income          |
|       November 2021      |
+----+-------------+-------+
| ID | Category    | Total |
+----+-------------+-------+
| 1  | Salary      | 2600  |
| 2  | Independent | 600   |
+----+-------------+-------+
create | show ID | update ID | delete ID
add-to ID | toggle | next | prev | logout
> next
+----+-------------+-------+
|          Income          |
|      December 2021       |
+----+-------------+-------+
| ID | Category    | Total |
+----+-------------+-------+
| 1  | Salary      | 0     |
| 2  | Independent | 800   |
+----+-------------+-------+
create | show ID | update ID | delete ID
add-to ID | toggle | next | prev | logout
> toggle
+----+----------------+-------+
|          Expenses           |
|        December 2021        |
+----+----------------+-------+
| ID | Category       | Total |
+----+----------------+-------+
| 3  | Food           | 206   |
| 4  | Transportation | 72    |
| 5  | Utilities      | 30    |
| 6  | Education      | 520   |
| 7  | Entertainment  | 25    |
| 8  | Other          | 220   |
+----+----------------+-------+
create | show ID | update ID | delete ID
add-to ID | toggle | next | prev | logout
>

Add-to (add transaction to a category)

The application allows adding a new transaction directly from the categories page with the option add-to [Category ID]. It will ask for the transaction data and make a post request to the API. Notice that you need to use a nested URL like /categories/[category_id]/transactions. Check on Insomnia if you have any doubts. If the response is successful, the program will add the transaction to the corresponding category and display the table again. The total column for that category should be updated.

> add-to 4
Amount: 5
Date: 2021-12-23
Notes: Visit a friend
+----+----------------+-------+
|          Expenses           |
|        December 2021        |
+----+----------------+-------+
| ID | Category       | Total |
+----+----------------+-------+
| 3  | Food           | 206   |
| 4  | Transportation | 77    |
| 5  | Utilities      | 30    |
| 6  | Education      | 520   |
| 7  | Entertainment  | 25    |
| 8  | Other          | 220   |
+----+----------------+-------+
create | show ID | update ID | delete ID
add-to ID | toggle | next | prev | logout
>

• amount: Positive integer. Error message "Cannot be zero"
• date: Required. Should have the format YYYY-MM-DD. Error message "Required format: YYYY-MM-DD"
• notes: optional

Show a category (show details)

The user can type show [Category ID] to see the transactions page with the list of transactions for that category. The menu on this page is different as well. The Date column should display the transaction date with the format shown below.

> show 4
+-----+-------------+--------+-----------------+
|                Transportation                |
|                December 2021                 |
+-----+-------------+--------+-----------------+
| ID  | Date        | Amount | Notes           |
+-----+-------------+--------+-----------------+
| 50  | Wed, Dec 1  | 15     | Taxis           |
| 51  | Sat, Dec 4  | 4      | Public          |
| 52  | Wed, Dec 8  | 13     | Taxis           |
| 53  | Fri, Dec 10 | 3      | Public          |
| 54  | Wed, Dec 15 | 14     | Taxis           |
| 55  | Mon, Dec 20 | 3      | Public          |
| 56  | Wed, Dec 22 | 15     | Taxis           |
| 995 | Wed, Dec 23 | 5      | Visit a friend  |
| 57  | Fri, Dec 24 | 5      | Public          |
+-----+-------------+--------+-----------------+
add | update ID | delete ID
next | prev | back
>

Add transaction

The option add creates a new transaction for the current category. Since the category_id is not provided by the user, your program should keep track of which is the current category that is being displayed to use that id on the API request.

> add
Amount: 9
Date: 2021-12-19 
Notes: More taxis
+-----+-------------+--------+-----------------+
|                Transportation                |
|                December 2021                 |
+-----+-------------+--------+-----------------+
| ID  | Date        | Amount | Notes           |
+-----+-------------+--------+-----------------+
| 50  | Wed, Dec 1  | 15     | Taxis           |
| 51  | Sat, Dec 4  | 4      | Public          |
| 52  | Wed, Dec 8  | 13     | Taxis           |
| 53  | Fri, Dec 10 | 3      | Public          |
| 54  | Wed, Dec 15 | 14     | Taxis           |
| 996 | Sun, Dec 19 | 9      | More taxis      |
| 55  | Mon, Dec 20 | 3      | Public          |
| 56  | Wed, Dec 22 | 15     | Taxis           |
| 995 | Wed, Dec 23 | 5      | Visit a friend  |
| 57  | Fri, Dec 24 | 5      | Public          |
+-----+-------------+--------+-----------------+
add | update ID | delete ID
next | prev | back
>

• Validations same as Add-to

Update transaction

If the user types update [transaction ID] with a valid id, the program will ask for the new transaction data and make a patch request to the API. Same as before, it needs the current category id to perform this operation.

> update 995
Amount: 7
Date: 2021-12-22
Notes: Updated expense
+-----+-------------+--------+-----------------+
|                Transportation                |
|                December 2021                 |
+-----+-------------+--------+-----------------+
| ID  | Date        | Amount | Notes           |
+-----+-------------+--------+-----------------+
| 50  | Wed, Dec 1  | 15     | Taxis           |
| 51  | Sat, Dec 4  | 4      | Public          |
| 52  | Wed, Dec 8  | 13     | Taxis           |
| 53  | Fri, Dec 10 | 3      | Public          |
| 54  | Wed, Dec 15 | 14     | Taxis           |
| 996 | Sun, Dec 19 | 9      | More taxis      |
| 55  | Mon, Dec 20 | 3      | Public          |
| 56  | Wed, Dec 22 | 15     | Taxis           |
| 995 | Wed, Dec 22 | 7      | Updated expense |
| 57  | Fri, Dec 24 | 5      | Public          |
+-----+-------------+--------+-----------------+
add | update ID | delete ID
next | prev | back
>

• amount and date required as in add transaction. notes is optional.
• If notes is left blank it shouldn't update the transaction notes attribute.∫

Delete transaction

If the user type delete [transaction ID] with a valid id, the program will aa delete request to the API. Same as before, it needs the current category id to perform this operation.

> delete 995
+-----+-------------+--------+-----------------+
|                Transportation                |
|                December 2021                 |
+-----+-------------+--------+-----------------+
| ID  | Date        | Amount | Notes           |
+-----+-------------+--------+-----------------+
| 50  | Wed, Dec 1  | 15     | Taxis           |
| 51  | Sat, Dec 4  | 4      | Public          |
| 52  | Wed, Dec 8  | 13     | Taxis           |
| 53  | Fri, Dec 10 | 3      | Public          |
| 54  | Wed, Dec 15 | 14     | Taxis           |
| 996 | Sun, Dec 19 | 9      | More taxis      |
| 55  | Mon, Dec 20 | 3      | Public          |
| 56  | Wed, Dec 22 | 15     | Taxis           |
| 57  | Fri, Dec 24 | 5      | Public          |
+-----+-------------+--------+-----------------+
add | update ID | delete ID
next | prev | back
>

Prev and Next (same as in categories page)

The prev and next options still works exactly as before. The program should just re-use the same methods as before.

> prev
+----+-------------+--------+--------+
|           Transportation           |
|            November 2021           |
+----+-------------+--------+--------+
| ID | Date        | Amount | Notes  |
+----+-------------+--------+--------+
| 42 | Thu, Nov 4  | 15     | Taxis  |
| 43 | Mon, Nov 8  | 4      | Public |
| 44 | Thu, Nov 11 | 12     | Taxis  |
| 45 | Mon, Nov 15 | 2      | Public |
| 46 | Thu, Nov 18 | 11     | Taxis  |
| 47 | Mon, Nov 22 | 3      | Public |
| 48 | Thu, Nov 25 | 12     | Taxis  |
| 49 | Sat, Nov 27 | 4      | Public |
+----+-------------+--------+--------+
add | update ID | delete ID
next | prev | back
> next
+-----+-------------+--------+-----------------+
|                Transportation                |
|                December 2021                 |
+-----+-------------+--------+-----------------+
| ID  | Date        | Amount | Notes           |
+-----+-------------+--------+-----------------+
| 50  | Wed, Dec 1  | 15     | Taxis           |
| 51  | Sat, Dec 4  | 4      | Public          |
| 52  | Wed, Dec 8  | 13     | Taxis           |
| 53  | Fri, Dec 10 | 3      | Public          |
| 54  | Wed, Dec 15 | 14     | Taxis           |
| 996 | Sun, Dec 19 | 9      | More taxis      |
| 55  | Mon, Dec 20 | 3      | Public          |
| 56  | Wed, Dec 22 | 15     | Taxis           |
| 57  | Fri, Dec 24 | 5      | Public          |
+-----+-------------+--------+-----------------+
add | update ID | delete ID
next | prev | back
>

Back

The back option sends the user to the categories page.

> back
+----+----------------+-------+
|          Expenses           |
|        December 2021        |
+----+----------------+-------+
| ID | Category       | Total |
+----+----------------+-------+
| 3  | Food           | 206   |
| 4  | Transportation | 81    |
| 5  | Utilities      | 30    |
| 6  | Education      | 520   |
| 7  | Entertainment  | 25    |
| 8  | Other          | 220   |
+----+----------------+-------+
create | show ID | update ID | delete ID
add-to ID | toggle | next | prev | logout
>

Exit

To exit the program, just type logout and then exit. The program shows an exit message.

> logout
####################################
#       Welcome to Expensable      #
####################################
login | create_user | exit
> exit
####################################
#    Thanks for using Expensable   #
####################################

Testing

Your program should implement at least 2 tests. You can choose what to test. We recommend to test methods that return some value over methods that print stuff to the terminal (you can explore this option but is a little more difficult).