game-example.kt

import java.lang.Math.ceil
import java.lang.Math.pow
import kotlin.math.log2

fun main() {

    println("\n Welcome to Up-To-9-Cards Game!")
    println("\n================================\n")
    displayCards(getCards())
    println("\n\nDone!\n")
}

fun getCards(): List<Int> {
    var validCount = 0
    val numbers = mutableListOf<Int>()

    while (validCount < 9) {
        print("Please enter a card or enter -1 to end: ")
        val codedNumber = readLine()!!.toInt()
        if (codedNumber == -1) {
            return numbers
        } else if (codedNumber < 0 || codedNumber > 51) {
            println("Not a valid card entry.")
        } else {
            numbers.add(codedNumber)
            validCount += 1
        }
    }
    return numbers
}

fun getSuitNumber(codedNumber: Int): Int = codedNumber % 4

fun getSuitString(codedNumber: Int): String {
    return when (getSuitNumber(codedNumber)) {
        0 -> "Clubs"
        1 -> "Spades"
        2 -> "Diamonds"
        3 -> "Hearts"
        else -> ""
    }
}

fun getCardValue(codedNumber: Int): Int = codedNumber / 4 + 1

fun displayCards(cards: List<Int>) {
    println("Your hand is:\n")
    cards.forEach {
        println("        ${getCardValue(it)} of ${getSuitString(it)}")
    }

    println("")
    val handValue = calculateHandValue(cards)
    println("The Total value of your hand is:\n$handValue points")
}

fun calculateHandValue(cards: List<Int>): Int {
    val baseScore = simpleSumCards(cards)

    var totalValue = baseScore
    if (hasThreeOrMoreNonNumberCards(cards)) {
        totalValue = totalValue * totalValue + 7
    }
    if (isPrime(totalValue)) {
        totalValue += nextHighestPowerOfTwo(totalValue)
    }
    return totalValue
}


fun nextHighestPowerOfTwo(value: Int): Int {
    return pow(2.toDouble(), ceil(log2(value.toDouble()))).toInt()
}

fun simpleSumCards(cards: List<Int>): Int {
    return cards.sumBy { getCardValue(it) - getSuitNumber(it) }
}

fun hasThreeOrMoreNonNumberCards(cards: List<Int>): Boolean {
    return cards.count { getCardValue(it) >= 11 || getCardValue(it) == 1 } >= 3
}

fun isPrime(number: Int): Boolean {
    return (2..number / 2).none { number % it == 0 }
}