package com.montran.ewallet.core

class HashMap<T>(
    private val maxSize: Int,
) {

    private var data = MutableList<T?>(maxSize) { null }

    private fun hash(key: String): Int
        = key.mapIndexed { index, char ->
            char.code * nthPrime(index)
        }
        .sum() % maxSize

    private fun nthPrime(n: Int): Int {
        var number = 2
        var count = 0

        while (count != n) {
            if (number.isPrime()) count++
            number++
        }
        return number - 1
    }

    private fun Int.isPrime(): Boolean {
        var div = 2
        while (div * div <= this / 2) {
            if (this % div == 0) {
                return false
            }
            div += 1
        }
        return true
    }

    fun put(key: String, value: T) {
        data[hash(key)] = value
    }

    fun at(key: String): T
        = data[hash(key)] ?: throw NullPointerException()
}


fun main() {
    val map = HashMap<Int>(200)

    map.put("abc", 12)
    map.put("acb", 123)
    println(map.at("abc"))
    println(map.at("acb"))
}