generateAlphanumericPassword (https://pl.kotl.in/DGX8N_Erw)

generateAlphanumericPassword.kt

import kotlin.random.Random.Default.nextInt

fun main() {
	println(generatePassword(16))
}

fun generatePassword(length: Int): String {
    require(length > 8) { "password length must be longer than 8 characters." }
    val lowerChars = ('a'..'z').toList()
    val upperChars = ('A'..'Z').toList()
    val numChars = ('0'..'9').toList()

    val chars1 = generateRandomChars(2, lowerChars)
    val chars2 = generateRandomChars(2, upperChars)
    val chars3 = generateRandomChars(2, numChars)
    val chars4 = generateRandomChars(length - 6, lowerChars + upperChars + numChars)
    return (chars1 + chars2 + chars3 + chars4).shuffled().joinToString("")
}

private fun generateRandomChars(length: Int, candidates: List<Char>): List<Char> {
    return (1..length).map { nextInt(0, candidates.size) }
            .map(candidates::get)
}