package main

import "math/rand/v2"

func generatePassword(sets [][]int, passwordLength int) []int {
	numSets := len(sets)
	totalLength := 0
	for _, set := range sets {
		totalLength += len(set)
	}

	props := make([]float64, numSets)
	for i := range props {
		props[i] = float64(len(sets[i])) / float64(totalLength)
	}

	numChars := make([]int, numSets)
	for i := range numChars {
		numChars[i] = int(props[i] * float64(passwordLength))
		if numChars[i] == 0 {
			numChars[i] = 1
		}
	}

	totalChars := 0
	for _, n := range numChars {
		totalChars += n
	}

	if totalChars < passwordLength {
		numChars[0]++
	} else if totalChars > passwordLength {
		numChars[numSets-1]--
	}

	password := make([]int, 0, passwordLength)
	for i, set := range sets {
		for j := 0; j < numChars[i]; j++ {
			password = append(password, set[rand.IntN(len(set))])
		}
	}

	rand.Shuffle(len(password), func(i, j int) {
		password[i], password[j] = password[j], password[i]
	})

	return password
}