Description

In this stage, we will add on another useful feature — the ability to indicate a deadline for a particular task. We will also work on a priority tag feature.

Of course, a task may come without a deadline. However, to keep things simple, a deadline is required for each task in this stage.

When users add a task, also ask them to input a date, time, and a priority tag. The latter is just one letter: C, H, N, L (case-insensitive) per task that stands for Critical, High, Normal, and Low, respectively.

Dates and time can be handled in many ways. However, in this project, we recommend using the Kotlinx datetime library. Kotlinx consists of valuable libraries that aren't a part of the standard library. To access the Kotlinx datetime library, it should be added to your project dependencies, but this has already been done for you. In order to use it, you should just import it to your program with:

import kotlinx.datetime.*

Following are some examples of how to use the datetime library:

// Create a LocalDate instance for 2017-4-29
val date = LocalDate(2017, 4, 29)

//Create a LocalDateTime instance for 2021-12-21 16:57
val dateTime = LocalDateTime(2021, 12, 31, 16, 57)
val year = dateTime.year         // Get year as an integer
val month = dateTime.monthNumber // Get month as an integer
val day = dateTime.dayOfMonth    // Get day as an integer
val hour = dateTime.hour         // Get hour as an integer
val minutes = dateTime.minute    // Get minutes as an integer

// Create a LocalDateTime instance for the current date and time for UTC+0 timezone
val dateTimeCurrent = Clock.System.now().toLocalDateTime(TimeZone.of("UTC+0"))
// Create a LocalDate instance for the current date and time for UTC+0 timezone
val dateCurrent = dateTimeCurrent.date

// Get the date and time as string
val dateTimeString = dateTime.toString()
// Print the string above
println(dateTimeString)  // Output 2021-12-31T16:57

// Same result as the above
println(dateTime)        // Output 2021-12-31T16:57

As can be seen, the LocalDateTime output string divides the date from the time with the character T.

Both LocalDate and LocalDateTime throw an IllegalArgumentException exception if the provided date or time data are invalid. They can be used for checking if a provided date is valid (based on leap years, number of days per month, etc.).

Finally, a word of caution. In stage 6, the task list data will be saved in a file in JSON format with the Moshi library. While the datetime library objects are serializable, to use them with Moshi, you need to register an explicit adapter. It is better to use the datetime library for date validation but keep the date and time data (in lists, classes, and so on.) as strings or integers.

Objectives

The program menu remains the same.

When users input add, do the following:

1. Ask users for the task priority with Input the task priority (C, H, N, L):

2. If users fail to provide any of the C, H, N, L priorities, ask them again (case-insensitive);

3. Ask for a date with Input the date (yyyy-mm-dd):

4. If users don't input a valid date, print The input date is invalid and ask again;

5. Ask the time with Input the time (hh:mm):

6. If users fail to provide a valid time, print The input time is invalid and ask again;

7. Ask users to input a task with Input a new task (enter a blank line to end): as in the previous stage;

8. If one blank line is provided, print The task is blank and don't save the task.

Note that the date should be a real date in the following format:

<year (4 digits)>-<number of month>-<number of day in the month>

Time should be in the following format:

<hour (0 - 23)>:<minutes (0 - 59)>

When the user inputs print, print the tasks as in the previous stage but with one difference — add the date, time, and priority to the first line for each task:

1  Date1 Time1 Priority1
   Task1-line1
   Task1-line2

2  Date2 Time2 Priority2
   Task2-line1

3  Date3 Time3 Priority3
   Task3-line1

4  Date4 Time4 Priority4
   Task4-line1
   Task4-line2

Separate the date, time, and priority by a single space.

If the number of months, number of days in the month, hour, or minutes is only one digit, they must be preceded by a leading zero. In this way, each of them will always be printed as a two-digit number.

Print a year as a four-digit number.

Examples

The greater-than symbol followed by a space (> ) represents the user input. Note that it's not part of the input.

Example 1: normal execution

Input an action (add, print, end):
> add
Input the task priority (C, H, N, L):
> H
Input the date (yyyy-mm-dd):
> 2021-12-25
Input the time (hh:mm):
> 14:00
Input a new task (enter a blank line to end):
> Christmas meal
>
Input an action (add, print, end):
> add
Input the task priority (C, H, N, L):
> n
Input the date (yyyy-mm-dd):
> 2022-1-12
Input the time (hh:mm):
> 19:15
Input a new task (enter a blank line to end):
> Dentist
>
Input an action (add, print, end):
> add
Input the task priority (C, H, N, L):
> L
Input the date (yyyy-mm-dd):
> 2021-12-23
Input the time (hh:mm):
> 9:0
Input a new task (enter a blank line to end):
> Supermarket
> -----------
> Pasta
> Butter
> Cheese
>
Input an action (add, print, end):
> print
1  2021-12-25 14:00 H
   Christmas meal

2  2022-01-12 19:15 N
   Dentist

3  2021-12-23 09:00 L
   Supermarket
   -----------
   Pasta
   Butter
   Cheese

Input an action (add, print, end):
> end
Tasklist exiting!

Example 2: wrong priority

Input an action (add, print, end):
> add
Input the task priority (C, H, N, L):
Critical
Input the task priority (C, H, N, L):
> normal
Input the task priority (C, H, N, L):
> n
Input the date (yyyy-mm-dd):
> 2022-1-1
Input the time (hh:mm):
> 12:00
Input a new task (enter a blank line to end):
> Call friends for new year greetings
>
Input an action (add, print, end):
> end
Tasklist exiting!

Example 3: wrong date

Input an action (add, print, end):
> add
Input the task priority (C, H, N, L):
> N
Input the date (yyyy-mm-dd):
> 2021-2-29
The input date is invalid
Input the date (yyyy-mm-dd):
> 2021-13-1
The input date is invalid
Input the date (yyyy-mm-dd):
> 2021-12-32
The input date is invalid
Input the date (yyyy-mm-dd):
> 2021-12-31
Input the time (hh:mm):
> 12:00
Input a new task (enter a blank line to end):
> Supermarket
>
Input an action (add, print, end):
> end
Tasklist exiting!

Example 4: wrong time

Input an action (add, print, end):
> add
Input the task priority (C, H, N, L):
> n
Input the date (yyyy-mm-dd):
> 2021-12-23
Input the time (hh:mm):
> 24:00
The input time is invalid
Input the time (hh:mm):
> 17:60
The input time is invalid
Input the time (hh:mm):
> 9:15
Input a new task (enter a blank line to end):
> Supermarket
>
Input an action (add, print, end):
> end
Tasklist exiting!

Example 5: blank task

Input an action (add, print, end):
> add
Input the task priority (C, H, N, L):
> H
Input the date (yyyy-mm-dd):
> 2021-11-11
Input the time (hh:mm):
> 9:15
Input a new task (enter a blank line to end):
>
The task is blank
Input an action (add, print, end):
> print
No tasks have been input
Input an action (add, print, end):
> end
Tasklist exiting!