/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2014-2018, Regents of the University of California.
 *
 * This file is part of NDN repo-ng (Next generation of NDN repository).
 * See AUTHORS.md for complete list of repo-ng authors and contributors.
 *
 * repo-ng 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.
 *
 * repo-ng 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 a copy of the GNU General Public License along with
 * repo-ng, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "write-handle.hpp"

#include <ndn-cxx/util/random.hpp>

namespace repo {

static const int RETRY_TIMEOUT = 3;
static const int DEFAULT_CREDIT = 12;
static const milliseconds NOEND_TIMEOUT(10000_ms);
static const milliseconds PROCESS_DELETE_TIME(10000_ms);
static const milliseconds DEFAULT_INTEREST_LIFETIME(4000_ms);

WriteHandle::WriteHandle(Face& face, RepoStorage& storageHandle, ndn::mgmt::Dispatcher& dispatcher,
                         Scheduler& scheduler, Validator& validator)
  : CommandBaseHandle(face, storageHandle, scheduler, validator)
  , m_validator(validator)
  , m_retryTime(RETRY_TIMEOUT)
  , m_credit(DEFAULT_CREDIT)
  , m_noEndTimeout(NOEND_TIMEOUT)
  , m_interestLifetime(DEFAULT_INTEREST_LIFETIME)
{
  dispatcher.addControlCommand<RepoCommandParameter>(ndn::PartialName("insert"),
    makeAuthorization(),
    std::bind(&WriteHandle::validateParameters<InsertCommand>, this, _1),
    std::bind(&WriteHandle::handleInsertCommand, this, _1, _2, _3, _4));

  dispatcher.addControlCommand<RepoCommandParameter>(ndn::PartialName("insert check"),
    makeAuthorization(),
    std::bind(&WriteHandle::validateParameters<InsertCheckCommand>, this, _1),
    std::bind(&WriteHandle::handleCheckCommand, this, _1, _2, _3, _4));
}

void
WriteHandle::deleteProcess(ProcessId processId)
{
  m_processes.erase(processId);
}

void
WriteHandle::handleInsertCommand(const Name& prefix, const Interest& interest,
                                 const ndn::mgmt::ControlParameters& parameter,
                                 const ndn::mgmt::CommandContinuation& done)
{
  RepoCommandParameter* repoParameter =
    dynamic_cast<RepoCommandParameter*>(const_cast<ndn::mgmt::ControlParameters*>(&parameter));

  if (repoParameter->hasStartBlockId() || repoParameter->hasEndBlockId()) {
    if (repoParameter->hasSelectors()) {
      done(negativeReply("BlockId present. BlockId is not supported in this protocol", 402));
      return;
    }
    processSegmentedInsertCommand(interest, *repoParameter, done);
  }
  else {
    processSingleInsertCommand(interest, *repoParameter, done);
  }
  if (repoParameter->hasInterestLifetime())
    m_interestLifetime = repoParameter->getInterestLifetime();
}

void
WriteHandle::onData(const Interest& interest, const Data& data, ProcessId processId)
{
  m_validator.validate(data,
                       bind(&WriteHandle::onDataValidated, this, interest, _1, processId),
                       bind(&WriteHandle::onDataValidationFailed, this, _1, _2));
}

void
WriteHandle::onDataValidated(const Interest& interest, const Data& data, ProcessId processId)
{
  if (m_processes.count(processId) == 0) {
    return;
  }

  ProcessInfo& process = m_processes[processId];
  RepoCommandResponse& response = process.response;

  if (response.getInsertNum() == 0) {
    storageHandle.insertData(data);
    response.setInsertNum(1);
  }

  deferredDeleteProcess(processId);
}

void
WriteHandle::onDataValidationFailed(const Data& data, const ValidationError& error)
{
  std::cerr << error << std::endl;
}

void
WriteHandle::onSegmentData(const Interest& interest, const Data& data, ProcessId processId)
{
  m_validator.validate(data,
                       bind(&WriteHandle::onSegmentDataValidated, this, interest, _1, processId),
                       bind(&WriteHandle::onDataValidationFailed, this, _1, _2));
}

void
WriteHandle::onSegmentDataValidated(const Interest& interest, const Data& data, ProcessId processId)
{
  auto it = m_processes.find(processId);
  if (it == m_processes.end()) {
    return;
  }
  RepoCommandResponse& response = it->second.response;

  //refresh endBlockId
  auto finalBlock = data.getFinalBlock();
  if (finalBlock && finalBlock->isSegment()) {
    auto finalSeg = finalBlock->toSegment();
    if (response.hasEndBlockId()) {
      if (finalSeg < response.getEndBlockId()) {
        response.setEndBlockId(finalSeg);
      }
    }
    else {
      response.setEndBlockId(finalSeg);
    }
  }

  //insert data
  if (storageHandle.insertData(data)) {
    response.setInsertNum(response.getInsertNum() + 1);
  }

  onSegmentDataControl(processId, interest);
}

void
WriteHandle::onTimeout(const Interest& interest, ProcessId processId)
{
  std::cerr << "Timeout" << std::endl;
  m_processes.erase(processId);
}

void
WriteHandle::onSegmentTimeout(const Interest& interest, ProcessId processId)
{
  std::cerr << "SegTimeout" << std::endl;

  onSegmentTimeoutControl(processId, interest);
}

void
WriteHandle::segInit(ProcessId processId, const RepoCommandParameter& parameter)
{
  ProcessInfo& process = m_processes[processId];
  process.credit = 0;

  map<SegmentNo, int>& processRetry = process.retryCounts;

  Name name = parameter.getName();
  SegmentNo startBlockId = parameter.getStartBlockId();

  uint64_t initialCredit = m_credit;

  if (parameter.hasEndBlockId()) {
    initialCredit =
      std::min(initialCredit, parameter.getEndBlockId() - parameter.getStartBlockId() + 1);
  }
  else {
    // set noEndTimeout timer
    process.noEndTime = ndn::time::steady_clock::now() +
                        m_noEndTimeout;
  }
  process.credit = initialCredit;
  SegmentNo segment = startBlockId;

  for (; segment < startBlockId + initialCredit; ++segment) {
    Name fetchName = name;
    fetchName.appendSegment(segment);
    Interest interest(fetchName);
    interest.setInterestLifetime(m_interestLifetime);
    face.expressInterest(interest,
                              bind(&WriteHandle::onSegmentData, this, _1, _2, processId),
                              bind(&WriteHandle::onSegmentTimeout, this, _1, processId), // Nack
                              bind(&WriteHandle::onSegmentTimeout, this, _1, processId));
    process.credit--;
    processRetry[segment] = 0;
  }

  queue<SegmentNo>& nextSegmentQueue = process.nextSegmentQueue;

  process.nextSegment = segment;
  nextSegmentQueue.push(segment);
}

void
WriteHandle::onSegmentDataControl(ProcessId processId, const Interest& interest)
{
  if (m_processes.count(processId) == 0) {
    return;
  }
  ProcessInfo& process = m_processes[processId];
  RepoCommandResponse& response = process.response;
  int& processCredit = process.credit;
  //onSegmentDataControl is called when a data returns.
  //When data returns, processCredit++
  processCredit++;
  SegmentNo& nextSegment = process.nextSegment;
  queue<SegmentNo>& nextSegmentQueue = process.nextSegmentQueue;
  map<SegmentNo, int>& retryCounts = process.retryCounts;

  //read whether notime timeout
  if (!response.hasEndBlockId()) {

    ndn::time::steady_clock::TimePoint& noEndTime = process.noEndTime;
    ndn::time::steady_clock::TimePoint now = ndn::time::steady_clock::now();

    if (now > noEndTime) {
      std::cerr << "noEndtimeout: " << processId << std::endl;
      //m_processes.erase(processId);
      //StatusCode should be refreshed as 405
      response.setCode(405);
      //schedule a delete event
      deferredDeleteProcess(processId);
      return;
    }
  }

  //read whether this process has total ends, if ends, remove control info from the maps
  if (response.hasEndBlockId()) {
    uint64_t nSegments =
      response.getEndBlockId() - response.getStartBlockId() + 1;
    if (response.getInsertNum() >= nSegments) {
      //m_processes.erase(processId);
      //All the data has been inserted, StatusCode is refreshed as 200
      response.setCode(200);
      deferredDeleteProcess(processId);
      return;
    }
  }

  //check whether there is any credit
  if (processCredit == 0)
    return;


  //check whether sent queue empty
  if (nextSegmentQueue.empty()) {
    //do not do anything
    return;
  }

  //pop the queue
  SegmentNo sendingSegment = nextSegmentQueue.front();
  nextSegmentQueue.pop();

  //check whether sendingSegment exceeds
  if (response.hasEndBlockId() && sendingSegment > response.getEndBlockId()) {
    //do not do anything
    return;
  }

  //read whether this is retransmitted data;
  SegmentNo fetchedSegment =
    interest.getName().get(interest.getName().size() - 1).toSegment();

  BOOST_ASSERT(retryCounts.count(fetchedSegment) != 0);

  //find this fetched data, remove it from this map
  //rit->second.erase(oit);
  retryCounts.erase(fetchedSegment);
  //express the interest of the top of the queue
  Name fetchName(interest.getName().getPrefix(-1));
  fetchName.appendSegment(sendingSegment);
  Interest fetchInterest(fetchName);
  fetchInterest.setInterestLifetime(m_interestLifetime);
  face.expressInterest(fetchInterest,
                            bind(&WriteHandle::onSegmentData, this, _1, _2, processId),
                            bind(&WriteHandle::onSegmentTimeout, this, _1, processId), // Nack
                            bind(&WriteHandle::onSegmentTimeout, this, _1, processId));
  //When an interest is expressed, processCredit--
  processCredit--;
  if (retryCounts.count(sendingSegment) == 0) {
    //not found
    retryCounts[sendingSegment] = 0;
  }
  else {
    //found
    retryCounts[sendingSegment] = retryCounts[sendingSegment] + 1;
  }
  //increase the next seg and put it into the queue
  if (!response.hasEndBlockId() || (nextSegment + 1) <= response.getEndBlockId()) {
    nextSegment++;
    nextSegmentQueue.push(nextSegment);
  }
}

void
WriteHandle::onSegmentTimeoutControl(ProcessId processId, const Interest& interest)
{
  if (m_processes.count(processId) == 0) {
    return;
  }
  ProcessInfo& process = m_processes[processId];
  // RepoCommandResponse& response = process.response;
  // SegmentNo& nextSegment = process.nextSegment;
  // queue<SegmentNo>& nextSegmentQueue = process.nextSegmentQueue;
  map<SegmentNo, int>& retryCounts = process.retryCounts;

  SegmentNo timeoutSegment = interest.getName().get(-1).toSegment();

  std::cerr << "timeoutSegment: " << timeoutSegment << std::endl;

  BOOST_ASSERT(retryCounts.count(timeoutSegment) != 0);

  //read the retry time. If retry out of time, fail the process. if not, plus
  int& retryTime = retryCounts[timeoutSegment];
  if (retryTime >= m_retryTime) {
    //fail this process
    std::cerr << "Retry timeout: " << processId << std::endl;
    m_processes.erase(processId);
    return;
  }
  else {
    //Reput it in the queue, retryTime++
    retryTime++;
    Interest retryInterest(interest.getName());
    retryInterest.setInterestLifetime(m_interestLifetime);
    face.expressInterest(retryInterest,
                              bind(&WriteHandle::onSegmentData, this, _1, _2, processId),
                              bind(&WriteHandle::onSegmentTimeout, this, _1, processId), // Nack
                              bind(&WriteHandle::onSegmentTimeout, this, _1, processId));
  }

}

void
WriteHandle::handleCheckCommand(const Name& prefix, const Interest& interest,
                                const ndn::mgmt::ControlParameters& parameter,
                                const ndn::mgmt::CommandContinuation& done)
{
  const RepoCommandParameter& repoParameter = dynamic_cast<const RepoCommandParameter&>(parameter);

  //check whether this process exists
  ProcessId processId = repoParameter.getProcessId();
  if (m_processes.count(processId) == 0) {
    std::cerr << "no such processId: " << processId << std::endl;
    done(negativeReply("No such this process is in progress", 404));
    return;
  }

  ProcessInfo& process = m_processes[processId];

  RepoCommandResponse& response = process.response;

  //Check whether it is single data fetching
  if (!response.hasStartBlockId() &&
      !response.hasEndBlockId()) {
    //reply(interest, response);
    done(response);
    return;
  }

  //read if noEndtimeout
  if (!response.hasEndBlockId()) {
    extendNoEndTime(process);
    done(response);
    return;
  }
  else {
    done(response);
  }
}

void
WriteHandle::deferredDeleteProcess(ProcessId processId)
{
  scheduler.scheduleEvent(PROCESS_DELETE_TIME,
                               bind(&WriteHandle::deleteProcess, this, processId));
}

void
WriteHandle::processSingleInsertCommand(const Interest& interest, RepoCommandParameter& parameter,
                                        const ndn::mgmt::CommandContinuation& done)
{
  ProcessId processId = ndn::random::generateWord64();

  ProcessInfo& process = m_processes[processId];

  RepoCommandResponse& response = process.response;
  response.setCode(100);
  response.setProcessId(processId);
  response.setInsertNum(0);
  response.setBody(response.wireEncode());
  done(response);

  response.setCode(300);

  Interest fetchInterest(parameter.getName());
  fetchInterest.setInterestLifetime(m_interestLifetime);
  if (parameter.hasSelectors()) {
    fetchInterest.setSelectors(parameter.getSelectors());
  }
  face.expressInterest(fetchInterest,
                       bind(&WriteHandle::onData, this, _1, _2, processId),
                       bind(&WriteHandle::onTimeout, this, _1, processId), // Nack
                       bind(&WriteHandle::onTimeout, this, _1, processId));
}

void
WriteHandle::processSegmentedInsertCommand(const Interest& interest, RepoCommandParameter& parameter,
                                           const ndn::mgmt::CommandContinuation& done)
{
  if (parameter.hasEndBlockId()) {
    //normal fetch segment
    SegmentNo startBlockId = parameter.hasStartBlockId() ? parameter.getStartBlockId() : 0;
    SegmentNo endBlockId = parameter.getEndBlockId();
    if (startBlockId > endBlockId) {
      done(negativeReply("Malformed Command", 403));
      return;
    }

    ProcessId processId = ndn::random::generateWord64();
    ProcessInfo& process = m_processes[processId];
    RepoCommandResponse& response = process.response;
    response.setCode(100);
    response.setProcessId(processId);
    response.setInsertNum(0);
    response.setStartBlockId(startBlockId);
    response.setEndBlockId(endBlockId);
    response.setBody(response.wireEncode());
    done(response);

    //300 means data fetching is in progress
    response.setCode(300);

    segInit(processId, parameter);
  }
  else {
    //no EndBlockId, so fetch FinalBlockId in data, if timeout, stop
    ProcessId processId = ndn::random::generateWord64();
    ProcessInfo& process = m_processes[processId];
    RepoCommandResponse& response = process.response;
    response.setCode(100);
    response.setProcessId(processId);
    response.setInsertNum(0);
    response.setStartBlockId(parameter.getStartBlockId());
    response.setBody(response.wireEncode());
    done(response);

    //300 means data fetching is in progress
    response.setCode(300);

    segInit(processId, parameter);
  }
}

void
WriteHandle::extendNoEndTime(ProcessInfo& process)
{
  ndn::time::steady_clock::TimePoint& noEndTime = process.noEndTime;
  ndn::time::steady_clock::TimePoint now = ndn::time::steady_clock::now();
  RepoCommandResponse& response = process.response;
  if (now > noEndTime) {
    response.setCode(405);
    return;
  }
  //extends noEndTime
  process.noEndTime = ndn::time::steady_clock::now() + m_noEndTimeout;

}

RepoCommandResponse
WriteHandle::negativeReply(std::string text, int statusCode)
{
  RepoCommandResponse response(statusCode, text);
  response.setBody(response.wireEncode());

  return response;
}

} // namespace repo