package main

import (
	"crypto/rand"
	"crypto/sha256"
	"encoding/hex"
	"encoding/json"
	"flag"
	"log"
	"os"

	"golang.org/x/crypto/pbkdf2"

	"sfu/group"
)

func main() {
	var iterations int
	var length int
	var saltLen int
	flag.IntVar(&iterations, "iterations", 4096, "number of iterations")
	flag.IntVar(&length, "key length", 32, "key length")
	flag.IntVar(&saltLen, "salt", 8, "salt length")
	flag.Parse()

	if len(flag.Args()) == 0 {
		flag.Usage()
		os.Exit(2)
	}

	salt := make([]byte, saltLen)

	for _, pw := range flag.Args() {
		_, err := rand.Read(salt)
		if err != nil {
			log.Fatalf("Salt: %v", err)
		}
		key := pbkdf2.Key(
			[]byte(pw), salt, iterations, length, sha256.New,
		)

		p := group.Password{
			Type:       "pbkdf2",
			Hash:       "sha-256",
			Key:        hex.EncodeToString(key),
			Salt:       hex.EncodeToString(salt),
			Iterations: iterations,
		}
		e := json.NewEncoder(os.Stdout)
		err = e.Encode(p)
		if err != nil {
			log.Fatalf("Encode: %v", err)
		}
	}
}