karlentwistle/ruby_home

module RubyHome
  class StartSRPService
    def initialize(username:, password:)
      @username = username
      @password = password
    end

    def salt_bytes
      [salt].pack("H*")
    end

    def public_key_bytes
      [public_key].pack("H*")
    end

    def proof
      challenge_and_proof[:proof]
    end

    private

    def salt
      user_auth[:salt]
    end

    def public_key
      challenge[:B]
    end

    def challenge
      challenge_and_proof[:challenge]
    end

    def challenge_and_proof
      srp_verifier.get_challenge_and_proof(username, user_auth[:verifier], user_auth[:salt])
    end

    def user_auth
      @_user_auth ||= srp_verifier.generate_userauth(username, password)
    end

    def srp_verifier
      @_verifier ||= RubyHome::SRP::Verifier.new
    end

    attr_reader :username, :password
  end
end