package main

import (
	"flag"
	"fmt"
	"github.com/chaosbunker/haveibeenpwned"
	"github.com/trustelem/zxcvbn"
	"math"
	"os"
)

func contains(arr [3]string, str string) bool {
	for _, a := range arr {
		if a == str {
			return true
		}
	}
	return false
}

func guessesToHuman(guesses float64) (result string) {
	minute := float64(60)
	hour := minute * 60
	day := hour * 24
	month := day * 31
	year := month * 12
	century := year * 100
	if guesses < 1 {
		result = "< 1 second"
	} else if guesses < minute {
		result = fmt.Sprintf("%d seconds", int(math.Round(guesses)))
	} else if guesses < hour {
		result = fmt.Sprintf("%d minutes", int(math.Round(guesses / minute)))
	} else if guesses < day {
		result = fmt.Sprintf("%d hours  ", int(math.Round(guesses / hour)))
	} else if guesses < month {
		result = fmt.Sprintf("%d days   ", int(math.Round(guesses / day)))
	} else if guesses < year {
		result = fmt.Sprintf("%d months ", int(math.Round(guesses / month)))
	} else if guesses < century {
		result = fmt.Sprintf("%d years  ", int(math.Round(guesses / year)))
	} else {
		result = fmt.Sprintf("Centuries")
	}
	return
}
type arrayFlags []string
func (i *arrayFlags) String() string {
	return "my string representation"
}

func (i *arrayFlags) Set(value string) error {
	*i = append(*i, value)
	return nil
}
func main() {
	var password string
	var pwnedFlag, haveIBeenPwned bool
	var words arrayFlags
	var err error

	flag.StringVar(&password,"password", "", "a password")
	flag.Var(&words, "word", "used words, e.g. -password p4ssw0rd -word password")
	flag.BoolVar(&pwnedFlag, "pwned", false, "check with haveibeenpwned API if password has been seen before")
	flag.Parse()

	if len(os.Args) == 1 || password == "" {
		flag.PrintDefaults()
		return
	}

	if pwnedFlag == true {
		haveIBeenPwned, err = pwned.IsPasswordCompromised(password)
	}

	if err != nil {
		fmt.Println("Something went wrong.")
	} else {
		strength := zxcvbn.PasswordStrength(password, words)
		guesses := strength.Guesses
		fmt.Printf("\nPassword:\t\t%s\n", password)
		fmt.Printf("Password strength:\t%d/4\n", strength.Score)

		fmt.Printf("Guesses Log10:\t\t%f\n", math.Log10(guesses))
		fmt.Println("\nGuess times")
		fmt.Printf("100 / h:\t\t%s\t(throttled online attack)\n", guessesToHuman(guesses * (3600 / 100)))
		fmt.Printf("10  / s:\t\t%s\t(unthrottled online attack)\n", guessesToHuman(guesses / 10))
		fmt.Printf("10k / s:\t\t%s\t(offline attack, slow hash, many cores)\n", guessesToHuman(guesses / 1e4))
		fmt.Printf("10b / s:\t\t%s\t(offline attack, fast hash, many cores)\n", guessesToHuman(guesses / 1e10))
	}
	if haveIBeenPwned == true {
		fmt.Println("\nThis password has been compromised and should not be used.")
	}
}