package bcrypt

import (
	"fmt"
	"golang.org/x/crypto/bcrypt"
)

var _ Password = (*password)(nil)

type Password interface {
	i()
	Generate(pwd string) string
	Validate(pwd, hash string) bool
}

type password struct {
	cost int
}

func (p *password) i() {}

func NewPassword(cost int) (Password, error) {
	if cost < bcrypt.MinCost || cost > bcrypt.MaxCost {
		return nil, fmt.Errorf("cost out of range")
	}
	return &password{
		cost: cost,
	}, nil
}

func (p *password) Generate(pwd string) string {
	hash, _ := bcrypt.GenerateFromPassword([]byte(pwd), p.cost)
	return string(hash)
}

func (p *password) Validate(pwd, hash string) bool {
	err := bcrypt.CompareHashAndPassword([]byte(hash), []byte(pwd))
	return err == nil
}