cmd.go

package main

import (
	"crypto/rand"
	"fmt"
	"math/big"

	"github.com/spf13/cobra"
)

const VERSION string = "1.1.0"

type CmdOptions struct {
	Length       int64
	Count        int64
	Additional   string
	AlphabetFlag bool
	NumberFlag   bool
	SpecialFlag  bool
	ShowVersion  bool
}

func RandomFromText(text string, length int64) (string, error) {
	if len(text) == 0 || length <= 0 {
		return "", nil
	}

	result := make([]rune, length)
	runes := []rune(text)

	for i := range length {
		n, err := rand.Int(rand.Reader, big.NewInt(int64(len(runes))))
		if err != nil {
			return "", err
		}
		result[i] = runes[n.Int64()]
	}

	return string(result), nil
}

func NewRootCommand() *cobra.Command {
	var opts CmdOptions

	cmd := &cobra.Command{
		Use:   "entropykey",
		Short: "Tiny utility to generate random secure passwords",
		Run: func(cmd *cobra.Command, args []string) {
			if opts.ShowVersion {
				fmt.Println("EntropyKey v" + VERSION)
				return
			}

			chars := opts.Additional

			if opts.AlphabetFlag {
				chars += "qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM"
			}
			if opts.NumberFlag {
				chars += "1234567890"
			}
			if opts.SpecialFlag {
				chars += "!#$%&()*+,-./:;<=>?@[]^_{|}~"
			}

			for range opts.Count {
				if password, err := RandomFromText(chars, opts.Length); err == nil {
					fmt.Println(password)
				} else {
					panic(err)
				}
			}
		},
	}

	cmd.Flags().Int64VarP(&opts.Length, "length", "l", 16, "Passphrase length")
	cmd.Flags().Int64VarP(&opts.Count, "count", "c", 4, "Passphrase count")
	cmd.Flags().StringVarP(&opts.Additional, "chars", "C", "", "Additional characters")
	cmd.Flags().BoolVarP(&opts.AlphabetFlag, "alphabet", "a", true, "Add alphabet characters")
	cmd.Flags().BoolVarP(&opts.NumberFlag, "number", "n", true, "Add number characters")
	cmd.Flags().BoolVarP(&opts.SpecialFlag, "special", "s", false, "Add special characters")

	cmd.Flags().BoolVarP(&opts.ShowVersion, "version", "v", false, "Show version")

	return cmd
}