Task

Write a simple tool to track a small set of data.

The tool should have a command-line interface to enter at least two different values.

The entered data should be stored in a structured format and saved to disk.

It does not matter what kind of data is being tracked.   It could be a collection (CDs, coins, baseball cards, books), a diary, an electronic organizer (birthdays/anniversaries/phone numbers/addresses), etc.



You should track the following details:

 A description of the item. (e.g., title, name)
 A category or tag (genre, topic, relationship such as “friend” or “family”)
 A date (either the date when the entry was made or some other date that is meaningful, like the birthday); the date may be generated or entered manually
 Other optional fields


The command should support the following Command-line arguments to run:

 Add a new entry
 Print the latest entry
 Print the latest entry for each category
 Print all entries sorted by a date


The category may be realized as a tag or as structure (by making all entries in that category subitems)

The file format on disk should be human readable, but it need not be standardized.   A natively available format that doesn't need an external library is preferred.   Avoid developing your own format if you can use an already existing one.   If there is no existing format available, pick one of:

   JSON
   S-Expressions
   YAML
   others


Related task

   Take notes on the command line 


// version 1.2.31
 
import java.text.SimpleDateFormat
import java.util.Date
import java.io.File
import java.io.IOException
 
val file = File("simdb.csv")
 
class Item(
    val name: String, 
    val date: String,
    val category: String
) : Comparable<Item> {
 
    override fun compareTo(other: Item) = date.compareTo(other.date)
 
    override fun toString() = "$name, $date, $category" 
}
 
fun addItem(input: Array<String>) {
    if (input.size < 2) {
        printUsage()
        return
    }
    val sdf = SimpleDateFormat("yyyy-MM-dd HH:mm:ss")
    val date = sdf.format(Date())
    val cat = if (input.size == 3) input[2] else "none"
    store(Item(input[1], date, cat))
}
 
fun printLatest(a: Array<String>) {
    val db = load()
    if (db.isEmpty()) {
        println("No entries in database.")
        return
    }
    // no need to sort db as items are added chronologically
    if (a.size == 2) {
        var found = false
        for (item in db.reversed()) {
            if (item.category == a[1]) {
                println(item)
                found = true
                break
            }
        }
        if (!found) println("There are no items for category '${a[1]}'")
    }
    else println(db[db.lastIndex])
}
 
fun printAll() {
    val db = load()
    if (db.isEmpty()) {
        println("No entries in database.")
        return
    }
    // no need to sort db as items are added chronologically
    for (item in db) println(item)
}
 
fun load(): MutableList<Item> {
    val db = mutableListOf<Item>()    
    try {
        file.forEachLine { line ->
            val item = line.split(", ")
            db.add(Item(item[0], item[1], item[2]))
        }
    }
    catch (e: IOException) {
        println(e)
        System.exit(1)
    }
    return db
}
 
fun store(item: Item) {
    try {
        file.appendText("$item\n")
    }
    catch (e: IOException) {
        println(e)
    }
}
 
fun printUsage() {
    println("""
        |Usage:
        |  simdb cmd [categoryName]
        |  add     add item, followed by optional category
        |  latest  print last added item(s), followed by optional category
        |  all     print all
        |  For instance: add "some item name" "some category name"
    """.trimMargin())
}
 
fun main(args: Array<String>) {
    if (args.size !in 1..3) {
        printUsage()
        return
    }
    file.createNewFile()  // create file if it doesn't already exist
    when (args[0].toLowerCase()) {
        "add"    -> addItem(args)
        "latest" -> printLatest(args)
        "all"    -> printAll()
        else     -> printUsage()
    }
}