Random String Generator in Golang

randomStr.go

/*
Author  : Ankur
Date : 17/10/21
*/

package main

import (
	"fmt"
	"math/rand"
	"strings"
	"time"
)

type randomStrGenerator struct {
	length      int
	specialChar bool
	caps        bool
	number      bool
}

func (obj randomStrGenerator) generate() string {
	rand.Seed(time.Now().UnixNano())
	setDefault(&obj)
	var result string
	var resultantSlice = []string{}
	mapRatio := map[string]bool{"specialCharRatio": obj.specialChar, "capsRatio": obj.caps, "numberRatio": obj.number}
	funcMap := map[string]func(int, *[]string){"specialCharRatio": generateSpecialCharSeries,
		"capsRatio": generateCapsSeries, "numberRatio": generateNumberSeries, "char": generateCharSeries}
	splitRatioData := splitRatio(obj.length, mapRatio)
	for key, value := range splitRatioData {
		funcMap[key](value, &resultantSlice)
	}
	result = shuffleAndJoin(resultantSlice)
	return result
}

func splitRatio(length int, mapRatio map[string]bool) map[string]int {
	lowerPercent, upperPercent := 10, 30
	randomizedPercentage := rand.Intn(upperPercent-lowerPercent) + lowerPercent
	deductedLength := 0
	var returnMap = map[string]int{}
	for key, value := range mapRatio {
		if value {
			tbDec := (length * randomizedPercentage) / 100
			returnMap[key] = tbDec
			deductedLength += tbDec
		}
	}
	returnMap["char"] = length - deductedLength
	return returnMap
}

func generateSeries(length, upperLimit, lowerLimit int, resultantSlice *[]string) {
	for i := 1; i <= length; i++ {
		char := rune(rand.Intn(upperLimit-lowerLimit) + lowerLimit)
		*resultantSlice = append(*resultantSlice, string(char))
	}

}

func generateCharSeries(length int, resultantSlice *[]string) {
	upperLimit := 122
	lowerLimit := 97
	generateSeries(length, upperLimit, lowerLimit, resultantSlice)
}

func generateSpecialCharSeries(length int, resultantSlice *[]string) {
	upperLimit := 64
	lowerLimit := 58
	generateSeries(length, upperLimit, lowerLimit, resultantSlice)
}

func generateCapsSeries(length int, resultantSlice *[]string) {
	upperLimit := 90
	lowerLimit := 65
	generateSeries(length, upperLimit, lowerLimit, resultantSlice)
}

func generateNumberSeries(length int, resultantSlice *[]string) {
	upperLimit := 57
	lowerLimit := 48
	generateSeries(length, upperLimit, lowerLimit, resultantSlice)
}

func shuffleAndJoin(resultantSlice []string) string {
	rand.Shuffle(len(resultantSlice), func(i, j int) {
		resultantSlice[i], resultantSlice[j] = resultantSlice[j], resultantSlice[i]
	})
	return strings.Join(resultantSlice, "")
}

func setDefault(val *randomStrGenerator) {
	len_data := &val.length
	if *len_data == 0 {
		*len_data = 10
	}

}

func main() {
	var genClass randomStrGenerator
	genClass.length = 110
	genClass.caps = true
	genClass.specialChar = false
	genClass.number = false
	randStr := genClass.generate()
	fmt.Println(randStr)
}