def createUserSession(user: User)(implicit session: DBSession): UserSession = {
    val now = DateTime.now(DateTimeZone.UTC)
    val userSession = new UserSession(user, securityHelper.generateToken(64), now.plusDays(1), securityHelper.generateToken(64), now.plusMonths(1))

    userSessionService.save(userSession)

    userSession
  }

  def signUp(user: User, password: String)(implicit session: DBSession): Try[Unit] = Try {

    user.passwordHash = Some(securityHelper.encode(password, user.username.get))

    userService.save(user)
  }

  def signIn(username: String, password: String)(implicit session: DBSession): Try[(User, UserSession)] = Try {

    val user = userDao.findByUsername(Some(username)).getOrElse(throw CREDENTIALS_ARE_INVALID)

    val encodedPassword = securityHelper.encode(password, username)
    if (!encodedPassword.equals(user.passwordHash.get)) throw CREDENTIALS_ARE_INVALID

    verify(user)

    val userSession = createUserSession(user)

    (user, userSession)
  }

  def emailSignUp(user: User, password: String)(implicit session: DBSession): Try[Unit] = Try {

    user.passwordHash = Some(securityHelper.encode(password, user.email.get))
    user.emailVerificationCode = Some(securityHelper.generateToken(64))

    val now = DateTime.now(DateTimeZone.UTC)
    user.emailVerificationCodeTimestamp = Some(now.plusDays(1))

    if (user.id == 0) userService.save(user)
    else userService.update(user)

    mailService.sendAccountVerificationEmail(user.email.get, user.emailVerificationCode.get)
  }

  def emailSignIn(email: String, password: String)(implicit session: DBSession): Try[(User, UserSession)] = Try {

    val user = userDao.findByEmail(Some(email)).getOrElse(throw CREDENTIALS_ARE_INVALID)

    val encodedPassword = securityHelper.encode(password, email)
    if (!encodedPassword.equals(user.passwordHash.get)) throw CREDENTIALS_ARE_INVALID

    verify(user)

    val userSession = createUserSession(user)

    (user, userSession)
  }

  ...