Simple Markov word generator

Markov.kt

import kotlin.random.Random

/**
 * A very simple, very dumb markov chain thing for generating made up names for a game I'm playing. Don't judge me on this.
 */
class Markov(input: List<String>){
     val dict = HashMap<Char, MutableMap<Char?, Int>>()
    private val starters = input.map { it.first() }

    init {
       input.forEach { name ->
            for (i in name.indices){
                var currentWeight = dict.getOrPut(name[i].toLowerCase()) { mutableMapOf() }
                                        .getOrPut(name.getOrNull(i+1)?.toLowerCase()) { 0 }

                currentWeight++

                dict[name[i].toLowerCase()]?.set(name.getOrNull(i+1)?.toLowerCase(), currentWeight)
            }
        }
    }

    fun getName(): String {
        var name = ""

        var curr: Char? = starters.random()

        while (curr != null ){
            curr?.let{ name += it }
            curr = dict[curr.toLowerCase()]?.weightedRandom()
            if(name.length < 3){
                var i = 0
                while (curr == null) {
                    i++
                    if(i > 200) return "broken - $name"
                    curr = dict[name.last().toLowerCase()]?.weightedRandom()
                }
            }
        }

        return name
    }

    private fun Map<Char?, Int>.weightedRandom(): Char? {
        val totalWeight = entries.sumBy { it.value }
        val r = Random.nextDouble() * totalWeight
        var countWeight = 0.0
        entries.toList().sortedBy { it.value }.forEach {
            countWeight += it.value
            if(countWeight >= r) return it.key
        }
        return null
    }
}