/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/**
 * Copyright (c) 2014,  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"

namespace repo {

static const int RETRY_TIMEOUT = 3;
static const int DEFAULT_CREDIT = 12;
static const ndn::time::milliseconds NOEND_TIMEOUT(10000);
static const ndn::time::milliseconds PROCESS_DELETE_TIME(10000);

WriteHandle::WriteHandle(Face& face, StorageHandle& storageHandle, KeyChain& keyChain,
                         Scheduler& scheduler, ValidatorConfig& validator)
  : BaseHandle(face, storageHandle, keyChain, scheduler)
  , m_validator(validator)
  , m_retryTime(RETRY_TIMEOUT)
  , m_credit(DEFAULT_CREDIT)
  , m_noEndTimeout(NOEND_TIMEOUT)
{
}

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

// Interest.
void
WriteHandle::onInterest(const Name& prefix, const Interest& interest)
{
  m_validator.validate(interest,
                          bind(&WriteHandle::onValidated, this, _1, prefix),
                          bind(&WriteHandle::onValidationFailed, this, _1, _2));
}

void
WriteHandle::onRegisterSuccess(const Name& prefix)
{
  std::cerr << "Successfully registered prefix " << prefix << std::endl;
}

// onRegisterFailed.
void
WriteHandle::onRegisterFailed(const Name& prefix, const std::string& reason)
{
  throw Error("Insert prefix registration failed");
}

// onRegisterFailed for insert.
void
WriteHandle::onCheckRegisterFailed(const Name& prefix, const std::string& reason)
{
  throw Error("Insert check prefix registration failed");
}

void
WriteHandle::onValidated(const shared_ptr<const Interest>& interest, const Name& prefix)
{
  //m_validResult = 1;
  RepoCommandParameter parameter;
  try {
    extractParameter(*interest, prefix, parameter);
  }
  catch (RepoCommandParameter::Error) {
    negativeReply(*interest, 403);
    return;
  }

  if (parameter.hasStartBlockId() || parameter.hasEndBlockId()) {
    if (parameter.hasSelectors()) {
      negativeReply(*interest, 402);
      return;
    }
    processSegmentedInsertCommand(*interest, parameter);
  }
  else {
    processSingleInsertCommand(*interest, parameter);
  }

}

void
WriteHandle::onValidationFailed(const shared_ptr<const Interest>& interest, const string& reason)
{
  std::cerr << reason << std::endl;
  negativeReply(*interest, 401);
}

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

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

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

  deferredDeleteProcess(processId);
}

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

  //refresh endBlockId
  Name::Component finalBlockId = data.getFinalBlockId();

  if (!finalBlockId.empty()) {
    SegmentNo final = finalBlockId.toSegment();
    if (response.hasEndBlockId()) {
      if (final < response.getEndBlockId()) {
        response.setEndBlockId(final);
      }
    }
    else {
      response.setEndBlockId(final);
    }
  }

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

  onSegmentDataControl(processId, interest);
}

void
WriteHandle::onTimeout(const ndn::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::listen(const Name& prefix)
{
  Name insertPrefix;
  insertPrefix.append(prefix).append("insert");
  getFace().setInterestFilter(insertPrefix,
                              bind(&WriteHandle::onInterest, this, _1, _2),
                              bind(&WriteHandle::onRegisterSuccess, this, _1),
                              bind(&WriteHandle::onRegisterFailed, this, _1, _2));
  Name insertCheckPrefix;
  insertCheckPrefix.append(prefix).append("insert check");
  getFace().setInterestFilter(insertCheckPrefix,
                              bind(&WriteHandle::onCheckInterest, this, _1, _2),
                              bind(&WriteHandle::onRegisterSuccess, this, _1),
                              bind(&WriteHandle::onRegisterFailed, this, _1, _2));
}

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);
    getFace().expressInterest(interest,
                              bind(&WriteHandle::onSegmentData, this, _1, _2, processId),
                              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.setStatusCode(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.setStatusCode(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);
  getFace().expressInterest(fetchInterest,
                            bind(&WriteHandle::onSegmentData, this, _1, _2, processId),
                            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());
    getFace().expressInterest(retryInterest,
                              bind(&WriteHandle::onSegmentData, this, _1, _2, processId),
                              bind(&WriteHandle::onSegmentTimeout, this, _1, processId));
  }

}

void
WriteHandle::onCheckInterest(const Name& prefix, const Interest& interest)
{
  m_validator.validate(interest,
                          bind(&WriteHandle::onCheckValidated, this, _1, prefix),
                          bind(&WriteHandle::onCheckValidationFailed, this, _1));

}

void
WriteHandle::onCheckValidated(const shared_ptr<const Interest>& interest, const Name& prefix)
{
  RepoCommandParameter parameter;
  try {
    extractParameter(*interest, prefix, parameter);
  }
  catch (RepoCommandParameter::Error) {
    negativeReply(*interest, 403);
    return;
  }

  if (!parameter.hasProcessId()) {
    negativeReply(*interest, 403);
    return;
  }
  //check whether this process exists
  ProcessId processId = parameter.getProcessId();
  if (m_processes.count(processId) == 0) {
    std::cerr << "no such processId: " << processId << std::endl;
    negativeReply(*interest, 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);
    return;
  }

  //read if noEndtimeout
  if (!response.hasEndBlockId()) {
    extendNoEndTime(process);
    reply(*interest, response);
    return;
  }
  else {
    reply(*interest, response);
  }
}

void
WriteHandle::onCheckValidationFailed(const shared_ptr<const Interest>& interest)
{
  negativeReply(*interest, 401);
}

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

void
WriteHandle::processSingleInsertCommand(const Interest& interest,
                                        RepoCommandParameter& parameter)
{
  ProcessId processId = generateProcessId();

  ProcessInfo& process = m_processes[processId];

  RepoCommandResponse& response = process.response;
  response.setStatusCode(100);
  response.setProcessId(processId);
  response.setInsertNum(0);

  reply(interest, response);

  response.setStatusCode(300);

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

void
WriteHandle::processSegmentedInsertCommand(const Interest& interest,
                                           RepoCommandParameter& parameter)
{
  if (parameter.hasEndBlockId()) {
    //normal fetch segment
    if (!parameter.hasStartBlockId()) {
      parameter.setStartBlockId(0);
    }

    SegmentNo startBlockId = parameter.getStartBlockId();
    SegmentNo endBlockId = parameter.getEndBlockId();
    if (startBlockId > endBlockId) {
      negativeReply(interest, 403);
      return;
    }

    ProcessId processId = generateProcessId();
    ProcessInfo& process = m_processes[processId];
    RepoCommandResponse& response = process.response;
    response.setStatusCode(100);
    response.setProcessId(processId);
    response.setInsertNum(0);
    response.setStartBlockId(startBlockId);
    response.setEndBlockId(endBlockId);

    reply(interest, response);

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

    segInit(processId, parameter);
  }
  else {
    //no EndBlockId, so fetch FinalBlockId in data, if timeout, stop
    ProcessId processId = generateProcessId();
    ProcessInfo& process = m_processes[processId];
    RepoCommandResponse& response = process.response;
    response.setStatusCode(100);
    response.setProcessId(processId);
    response.setInsertNum(0);
    response.setStartBlockId(parameter.getStartBlockId());
    reply(interest, response);

    //300 means data fetching is in progress
    response.setStatusCode(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.setStatusCode(405);
    return;
  }
  //extends noEndTime
  process.noEndTime =
    ndn::time::steady_clock::now() + m_noEndTimeout;

}

void
WriteHandle::negativeReply(const Interest& interest, int statusCode)
{
  RepoCommandResponse response;
  response.setStatusCode(statusCode);
  reply(interest, response);
}

} //namespace repo