/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/**
 * Copyright (c) 2017, Regents of the University of California.
 *
 * This file is part of ndncert, a certificate management system based on NDN.
 *
 * ndncert is free software: you can redistribute it and/or modify it under the terms
 * of the GNU General Public License as published by the Free Software Foundation, either
 * version 3 of the License, or (at your option) any later version.
 *
 * ndncert is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE.  See the GNU General Public License for more details.
 *
 * You should have received copies of the GNU General Public License along with
 * ndncert, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
 *
 * See AUTHORS.md for complete list of ndncert authors and contributors.
 */

#include "challenge-pin.hpp"
#include "json-helper.hpp"
#include <ndn-cxx/util/random.hpp>

namespace ndn {
namespace ndncert {

NDNCERT_REGISTER_CHALLENGE(ChallengePin, "PIN");

const std::string ChallengePin::NEED_CODE = "need-code";
const std::string ChallengePin::WRONG_CODE = "wrong-code";
const std::string ChallengePin::FAILURE_TIMEOUT = "failure-timeout";
const std::string ChallengePin::FAILURE_MAXRETRY = "failure-max-retry";

const std::string ChallengePin::JSON_CODE_TP = "code-timepoint";
const std::string ChallengePin::JSON_PIN_CODE = "code";
const std::string ChallengePin::JSON_ATTEMPT_TIMES = "attempt-times";

ChallengePin::ChallengePin(const size_t& maxAttemptTimes, const time::seconds& secretLifetime)
  : ChallengeModule("PIN")
  , m_secretLifetime(secretLifetime)
  , m_maxAttemptTimes(maxAttemptTimes)
{
}

JsonSection
ChallengePin::processSelectInterest(const Interest& interest, CertificateRequest& request)
{
  // interest format: /CA/_SELECT/{"request-id":"id"}/PIN/<signature>
  request.setStatus(NEED_CODE);
  request.setChallengeType(CHALLENGE_TYPE);
  request.setChallengeSecrets(generateStoredSecrets(time::system_clock::now(),
                                                    generateSecretCode(),
                                                    m_maxAttemptTimes));
  return genResponseChallengeJson(request.getRequestId(), CHALLENGE_TYPE, NEED_CODE);
}

JsonSection
ChallengePin::processValidateInterest(const Interest& interest, CertificateRequest& request)
{
  // interest format: /CA/_VALIDATION/{"request-id":"id"}/PIN/{"code":"code"}/<signature>
  JsonSection infoJson = getJsonFromNameComponent(interest.getName(), request.getCaName().size() + 3);
  std::string givenCode = infoJson.get<std::string>(JSON_PIN_CODE);

  const auto parsedSecret = parseStoredSecrets(request.getChallengeSecrets());
  if (time::system_clock::now() - std::get<0>(parsedSecret) >= m_secretLifetime) {
    // secret expires
    request.setStatus(FAILURE_TIMEOUT);
    request.setChallengeSecrets(JsonSection());
    return genResponseChallengeJson(request.getRequestId(), CHALLENGE_TYPE, FAILURE_TIMEOUT);
  }
  else if (givenCode == std::get<1>(parsedSecret)) {
    request.setStatus(SUCCESS);
    request.setChallengeSecrets(JsonSection());
    Name downloadName = genDownloadName(request.getCaName(), request.getRequestId());
    return genResponseChallengeJson(request.getRequestId(), CHALLENGE_TYPE, SUCCESS, downloadName);
  }
  else {
    // check rest attempt times
    if (std::get<2>(parsedSecret) > 1) {
      int restAttemptTimes = std::get<2>(parsedSecret) - 1;
      request.setStatus(WRONG_CODE);
      request.setChallengeSecrets(generateStoredSecrets(std::get<0>(parsedSecret),
                                                        std::get<1>(parsedSecret),
                                                        restAttemptTimes));
      return genResponseChallengeJson(request.getRequestId(), CHALLENGE_TYPE, WRONG_CODE);
    }
    else {
      // run out times
      request.setStatus(FAILURE_MAXRETRY);
      request.setChallengeSecrets(JsonSection());
      return genResponseChallengeJson(request.getRequestId(), CHALLENGE_TYPE, FAILURE_MAXRETRY);
    }
  }
}

std::list<std::string>
ChallengePin::getSelectRequirements()
{
  std::list<std::string> result;
  return result;
}

std::list<std::string>
ChallengePin::getValidateRequirements(const std::string& status)
{
  std::list<std::string> result;
  if (status == NEED_CODE) {
    result.push_back("Please input your verification code:");
  }
  else if (status == WRONG_CODE) {
    result.push_back("Incorrect PIN code, please input your verification code:");
  }
  return result;
}

JsonSection
ChallengePin::genChallengeInfo(const std::string& interestType, const std::string& status,
                               const std::list<std::string>& paramList)
{
  JsonSection result;
  if (interestType == "_SELECT") {
    BOOST_ASSERT(paramList.size() == 0);
  }
  else if (interestType == "_VALIDATE") {
    BOOST_ASSERT(paramList.size() == 1);
    result.put(JSON_PIN_CODE, paramList.front());
  }
  return result;
}

std::tuple<time::system_clock::TimePoint, std::string, int>
ChallengePin::parseStoredSecrets(const JsonSection& storedSecrets)
{
  auto tp = time::fromIsoString(storedSecrets.get<std::string>(JSON_CODE_TP));
  std::string rightCode= storedSecrets.get<std::string>(JSON_PIN_CODE);
  int attemptTimes = std::stoi(storedSecrets.get<std::string>(JSON_ATTEMPT_TIMES));

  return std::make_tuple(tp, rightCode, attemptTimes);
}

JsonSection
ChallengePin::generateStoredSecrets(const time::system_clock::TimePoint& tp,
                                    const std::string& secretCode, int attempTimes)
{
  JsonSection json;
  json.put(JSON_CODE_TP, time::toIsoString(tp));
  json.put(JSON_PIN_CODE, secretCode);
  json.put(JSON_ATTEMPT_TIMES, std::to_string(attempTimes));
  return json;
}

} // namespace ndncert
} // namespace ndn