main.go

package main

import (
	"fmt"
	"math/rand"
	"os"
	"strconv"
	"sync"
	"time"
)

func main() {
	userArgs := os.Args
	var (
		length = 7
		times  = 1
		prefix = ``
		sufix  = ``
		err    error
	)
	for pos, arg := range userArgs {
		switch arg {
		case `-h`:
			help()
			return
		case `-l`:
			length, err = strconv.Atoi(userArgs[pos+1])
			if err != nil {
				fmt.Println(`Você deve usar apenas numeros no tamanho solicitado! - `, err)
			}
		case `-t`:
			times, err = strconv.Atoi(userArgs[pos+1])
			if err != nil {
				fmt.Println(`Você deve usar apenas numeros na quantidade solicitado! - `, err)
			}
		case `-pf`:
			prefix = userArgs[pos+1]
		case `-sf`:
			sufix = userArgs[pos+1]
		}
	}
	wg := sync.WaitGroup{}
	wg.Add(times)
	for index := 0; index < times; index++ {
		go func() {
			defer wg.Done()
			fmt.Println(prefix + RandStringBytesMaskImprSrc(length) + sufix)
		}()
	}
	wg.Wait()
}

// Thanks: https://stackoverflow.com/questions/22892120/how-to-generate-a-random-string-of-a-fixed-length-in-go

var src = rand.NewSource(time.Now().UnixNano())

const letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
const (
	letterIdxBits = 6                    // 6 bits to represent a letter index
	letterIdxMask = 1<<letterIdxBits - 1 // All 1-bits, as many as letterIdxBits
	letterIdxMax  = 63 / letterIdxBits   // # of letter indices fitting in 63 bits
)

func RandStringBytesMaskImprSrc(n int) string {
	b := make([]byte, n)
	// A src.Int63() generates 63 random bits, enough for letterIdxMax characters!
	for i, cache, remain := n-1, src.Int63(), letterIdxMax; i >= 0; {
		if remain == 0 {
			cache, remain = src.Int63(), letterIdxMax
		}
		if idx := int(cache & letterIdxMask); idx < len(letterBytes) {
			b[i] = letterBytes[idx]
			i--
		}
		cache >>= letterIdxBits
		remain--
	}

	return string(b)
}

func help() {
	fmt.Println(`
	 ___ __ ____ ____ ____      ___ ____ __ _ ____ ____  __ ____ __ ____ 
	/ __/  (    ( __ / ___)___ / __(  __(  ( (  __(  _ \/ _(_  _/  (  _ \
       ( (_(  0 ) D ((__ \___ (___( (_ \) _)/    /) _) )   /    \)((  O )   /
	\___\__(____(____(____/    \___(____\_)__(____(__\_\_/\_(__)\__(__\_)

	-h			Ajuda | Help
	-l			Tamanho do código | Code Length
	-t			Quantidade de códigos | Quantity Codes
	-pf			Prefixo do Código | Code Prefix
	-sf			Sufixo do Código | Code Sufix

	Exemplo | Example: ./c0des-generator -l 25 -t 5 -pf LookThisAlien_ -sf -RightHere
	Saida | Output:
		LookThisAlien_DodjKGxptKqLhnAofEZzTQEWW-RightHere
		LookThisAlien_bHQBNyAbpJqScsxVjfGLUFjGq-RightHere
		LookThisAlien_oifsbYBkFDAUnmSKKFImnZAED-RightHere
		LookThisAlien_pxVMpxTqSNkswNuSElcwXXqLM-RightHere
		LookThisAlien_KyZBuuzwdaGYsQeRYDHeuxhkP-RightHere

			.     .       .  .   . .   .   . .    +  .
		  .     .  :     .    .. :. .___---------___.
		       .  .   .    .  :.:. _".^ .^ ^.  '.. :"-_. .
		    .  :       .  .  .:../:            . .^  :.:\.
		        .   . :: +. :.:/: .   .    .        . . .:\
		 .  :    .     . _ :::/:               .  ^ .  . .:\
		  .. . .   . - : :.:./.                        .  .:\
		  .      .     . :..|:                    .  .  ^. .:|
		    .       . : : ..||        .                . . !:|
		  .     . . . ::. ::\(                           . :)/
		 .   .     : . : .:.|. ######              .#######::|
		  :.. .  :-  : .:  ::|.#######           ..########:|
		 .  .  .  ..  .  .. :\ ########          :######## :/
		  .        .+ :: : -.:\ ########       . ########.:/
		    .  .+   . . . . :.:\. #######       #######..:/
		      :: . . . . ::.:..:.\           .   .   ..:/
		   .   .   .  .. :  -::::.\.       | |     . .:/
		      .  :  .  .  .-:.":.::.\             ..:/
		 .      -.   . . . .: .:::.:.\.           .:/
		.   .   .  :      : ....::_:..:\   ___.  :/
		   .   .  .   .:. .. .  .: :.:.:\       :/
		     +   .   .   : . ::. :.:. .:.|\  .:/|
		     .         +   .  .  ...:: ..|  --.:|
		.      . . .   .  .  . ... :..:.."(  ..)"
		 .   .       .      :  .   .: ::/  .  .::\
			
		 	Rafael Gomides - mrrafagomides@gmail.com
				Twitter: @HellGomides
		 		GitHub: RafaelGomides
	`)
}