/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/**
 * Copyright (c) 2014  University of Memphis,
 *                     Regents of the University of California
 *
 * This file is part of NLSR (Named-data Link State Routing).
 * See AUTHORS.md for complete list of NLSR authors and contributors.
 *
 * NLSR 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.
 *
 * NLSR 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
 * NLSR, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
 *
 * \author A K M Mahmudul Hoque <ahoque1@memphis.edu>
 *
 **/
#include <iostream>
#include <cmath>
#include "lsdb.hpp"
#include "routing-table-calculator.hpp"
#include "map.hpp"
#include "lsa.hpp"
#include "nexthop.hpp"
#include "nlsr.hpp"
#include "logger.hpp"

namespace nlsr {

INIT_LOGGER("RoutingTableCalculator");
using namespace std;

void
RoutingTableCalculator::allocateAdjMatrix()
{
  adjMatrix = new double*[numOfRouter];
  for (int i = 0; i < numOfRouter; ++i) {
    adjMatrix[i] = new double[numOfRouter];
  }
}

void
RoutingTableCalculator::initMatrix()
{
  for (int i = 0; i < numOfRouter; i++) {
    for (int j = 0; j < numOfRouter; j++) {
      adjMatrix[i][j] = 0;
    }
  }
}

void
RoutingTableCalculator::makeAdjMatrix(Nlsr& pnlsr, Map pMap)
{
  std::list<AdjLsa> adjLsdb = pnlsr.getLsdb().getAdjLsdb();
  for (std::list<AdjLsa>::iterator it = adjLsdb.begin();
       it != adjLsdb.end() ; it++) {
    int row = pMap.getMappingNoByRouterName((*it).getOrigRouter());
    std::list<Adjacent> adl = (*it).getAdl().getAdjList();
    for (std::list<Adjacent>::iterator itAdl = adl.begin();
         itAdl != adl.end() ; itAdl++) {
      int col = pMap.getMappingNoByRouterName((*itAdl).getName());
      double cost = (*itAdl).getLinkCost();
      if ((row >= 0 && row < numOfRouter) && (col >= 0 && col < numOfRouter)) {
        adjMatrix[row][col] = cost;
      }
    }
  }
}

void
RoutingTableCalculator::writeAdjMatrixLog()
{
  for (int i = 0; i < numOfRouter; i++) {
    string line="";
    for (int j = 0; j < numOfRouter; j++) {
      line += boost::lexical_cast<std::string>(adjMatrix[i][j]);
      line += " ";
    }
    _LOG_DEBUG(line);
  }
}

void
RoutingTableCalculator::adjustAdMatrix(int source, int link, double linkCost)
{
  for (int i = 0; i < numOfRouter; i++) {
    if (i == link) {
      adjMatrix[source][i] = linkCost;
    }
    else {
      adjMatrix[source][i] = 0;
    }
  }
}

int
RoutingTableCalculator::getNumOfLinkfromAdjMatrix(int sRouter)
{
  int noLink = 0;
  for (int i = 0; i < numOfRouter; i++) {
    if (adjMatrix[sRouter][i] > 0) {
      noLink++;
    }
  }
  return noLink;
}

void
RoutingTableCalculator::getLinksFromAdjMatrix(int* links,
                                              double* linkCosts, int source)
{
  int j = 0;
  for (int i = 0; i < numOfRouter; i++) {
    if (adjMatrix[source][i] > 0) {
      links[j] = i;
      linkCosts[j] = adjMatrix[source][i];
      j++;
    }
  }
}

void
RoutingTableCalculator::freeAdjMatrix()
{
  for (int i = 0; i < numOfRouter; ++i) {
    delete [] adjMatrix[i];
  }
  delete [] adjMatrix;
}


void
RoutingTableCalculator::allocateLinks()
{
  links = new int[vNoLink];
}

void
RoutingTableCalculator::allocateLinkCosts()
{
  linkCosts = new double[vNoLink];
}


void
RoutingTableCalculator::freeLinks()
{
  delete [] links;
}
void
RoutingTableCalculator::freeLinksCosts()
{
  delete [] linkCosts;
}

void
LinkStateRoutingTableCalculator::calculatePath(Map& pMap,
                                               RoutingTable& rt, Nlsr& pnlsr)
{
  _LOG_DEBUG("LinkStateRoutingTableCalculator::calculatePath Called");
  allocateAdjMatrix();
  initMatrix();
  makeAdjMatrix(pnlsr, pMap);
  writeAdjMatrixLog();
  int sourceRouter = pMap.getMappingNoByRouterName(pnlsr.getConfParameter().getRouterPrefix());
  allocateParent();
  allocateDistance();
  if (pnlsr.getConfParameter().getMaxFacesPerPrefix() == 1) {
    // Single Path
    doDijkstraPathCalculation(sourceRouter);
    // update routing table
    addAllLsNextHopsToRoutingTable(pnlsr, rt, pMap, sourceRouter);
  }
  else {
    // Multi Path
    setNoLink(getNumOfLinkfromAdjMatrix(sourceRouter));
    allocateLinks();
    allocateLinkCosts();
    getLinksFromAdjMatrix(links, linkCosts, sourceRouter);
    for (int i = 0 ; i < vNoLink; i++) {
      adjustAdMatrix(sourceRouter, links[i], linkCosts[i]);
      writeAdjMatrixLog();
      doDijkstraPathCalculation(sourceRouter);
      //update routing table
      addAllLsNextHopsToRoutingTable(pnlsr, rt, pMap, sourceRouter);
    }
    freeLinks();
    freeLinksCosts();
  }
  freeParent();
  freeDistance();
  freeAdjMatrix();
}

void
LinkStateRoutingTableCalculator::doDijkstraPathCalculation(int sourceRouter)
{
  int i;
  int v, u;
  int* Q = new int[numOfRouter];
  int head = 0;
  /* Initiate the Parent */
  for (i = 0 ; i < numOfRouter; i++) {
    m_parent[i] = EMPTY_PARENT;
    m_distance[i] = INF_DISTANCE;
    Q[i] = i;
  }
  if (sourceRouter != NO_MAPPING_NUM) {
    m_distance[sourceRouter] = 0;
    sortQueueByDistance(Q, m_distance, head, numOfRouter);
    while (head < numOfRouter) {
      u = Q[head];
      if (m_distance[u] == INF_DISTANCE) {
        break;
      }
      for (v = 0 ; v < numOfRouter; v++) {
        if (adjMatrix[u][v] > 0) {
          if (isNotExplored(Q, v, head + 1, numOfRouter)) {
            if (m_distance[u] + adjMatrix[u][v] <  m_distance[v]) {
              m_distance[v] = m_distance[u] + adjMatrix[u][v] ;
              m_parent[v] = u;
            }
          }
        }
      }
      head++;
      sortQueueByDistance(Q, m_distance, head, numOfRouter);
    }
  }
  delete [] Q;
}

void
LinkStateRoutingTableCalculator::addAllLsNextHopsToRoutingTable(Nlsr& pnlsr,
                                                                RoutingTable& rt, Map& pMap, int sourceRouter)
{
  _LOG_DEBUG("LinkStateRoutingTableCalculator::addAllNextHopsToRoutingTable Called");
  int nextHopRouter = 0;
  for (int i = 0; i < numOfRouter ; i++) {
    if (i != sourceRouter) {
      nextHopRouter = getLsNextHop(i, sourceRouter);
      if (nextHopRouter != NO_NEXT_HOP) {
        double routeCost = m_distance[i];
        ndn::Name nextHopRouterName = pMap.getRouterNameByMappingNo(nextHopRouter);
        std::string nextHopFace =
          pnlsr.getAdjacencyList().getAdjacent(nextHopRouterName).getConnectingFaceUri();
        // Add next hop to routing table
        NextHop nh(nextHopFace, routeCost);
        rt.addNextHop(pMap.getRouterNameByMappingNo(i), nh);
      }
    }
  }
}

int
LinkStateRoutingTableCalculator::getLsNextHop(int dest, int source)
{
  int nextHop = NO_NEXT_HOP;
  while (m_parent[dest] != EMPTY_PARENT) {
    nextHop = dest;
    dest = m_parent[dest];
  }
  if (dest != source) {
    nextHop = NO_NEXT_HOP;
  }
  return nextHop;
}

void
LinkStateRoutingTableCalculator::sortQueueByDistance(int* Q,
                                                     double* dist,
                                                     int start, int element)
{
  for (int i = start ; i < element ; i++) {
    for (int j = i + 1; j < element; j++) {
      if (dist[Q[j]] < dist[Q[i]]) {
        int tempU = Q[j];
        Q[j] = Q[i];
        Q[i] = tempU;
      }
    }
  }
}

int
LinkStateRoutingTableCalculator::isNotExplored(int* Q,
                                               int u, int start, int element)
{
  int ret = 0;
  for (int i = start; i < element; i++) {
    if (Q[i] == u) {
      ret = 1;
      break;
    }
  }
  return ret;
}

void
LinkStateRoutingTableCalculator::allocateParent()
{
  m_parent = new int[numOfRouter];
}

void
LinkStateRoutingTableCalculator::allocateDistance()
{
  m_distance = new double[numOfRouter];
}

void
LinkStateRoutingTableCalculator::freeParent()
{
  delete [] m_parent;
}

void LinkStateRoutingTableCalculator::freeDistance()
{
  delete [] m_distance;
}


void
HypRoutingTableCalculator::calculatePath(Map& pMap,
                                         RoutingTable& rt, Nlsr& pnlsr)
{
  allocateAdjMatrix();
  initMatrix();
  makeAdjMatrix(pnlsr, pMap);
  ndn::Name routerName = pnlsr.getConfParameter().getRouterPrefix();
  int sourceRouter = pMap.getMappingNoByRouterName(routerName);
  int noLink = getNumOfLinkfromAdjMatrix(sourceRouter);
  setNoLink(noLink);
  allocateLinks();
  allocateLinkCosts();
  getLinksFromAdjMatrix(links, linkCosts, sourceRouter);
  for (int i = 0 ; i < numOfRouter ; ++i) {
    int k = 0;
    if (i != sourceRouter) {
      allocateNexthopRouters();
      allocateDistanceToNeighbor();
      allocateDistFromNbrToDest();
      for (int j = 0; j < vNoLink; j++) {
        double distToNbr = getHyperbolicDistance(pnlsr, pMap,
                                                 sourceRouter, links[j]);
        double distToDestFromNbr = getHyperbolicDistance(pnlsr,
                                                         pMap, links[j], i);
        if (distToDestFromNbr >= 0) {
          m_nexthopRouters[k] = links[j];
          m_distanceToNeighbor[k] = distToNbr;
          m_distFromNbrToDest[k] = distToDestFromNbr;
          k++;
        }
      }
      addHypNextHopsToRoutingTable(pnlsr, pMap, rt, k, i);
      freeNexthopRouters();
      freeDistanceToNeighbor();
      freeDistFromNbrToDest();
    }
  }
  freeLinks();
  freeLinksCosts();
  freeAdjMatrix();
}

void
HypRoutingTableCalculator::addHypNextHopsToRoutingTable(Nlsr& pnlsr, Map& pMap,
                                                        RoutingTable& rt, int noFaces, int dest)
{
  ndn::Name destRouter = pMap.getRouterNameByMappingNo(dest);
  for (int i = 0 ; i < noFaces ; ++i) {
    ndn::Name nextHopRouterName = pMap.getRouterNameByMappingNo(m_nexthopRouters[i]);
    std::string nextHopFaceUri =
         pnlsr.getAdjacencyList().getAdjacent(nextHopRouterName).getConnectingFaceUri();
    NextHop nh(nextHopFaceUri, m_distFromNbrToDest[i]);
    if (m_isDryRun) {
      rt.addNextHopToDryTable(destRouter, nh);
    }
    else {
      rt.addNextHop(destRouter, nh);
    }
  }
}

double
HypRoutingTableCalculator::getHyperbolicDistance(Nlsr& pnlsr,
                                                 Map& pMap, int src, int dest)
{
  double distance = 0.0;
  ndn::Name srcRouterKey = pMap.getRouterNameByMappingNo(src);
  srcRouterKey.append("coordinate");
  ndn::Name destRouterKey = pMap.getRouterNameByMappingNo(dest);
  destRouterKey.append("coordinate");
  CoordinateLsa* srcLsa = pnlsr.getLsdb().findCoordinateLsa(srcRouterKey);
  CoordinateLsa* destLsa = pnlsr.getLsdb().findCoordinateLsa(destRouterKey);

  if ((srcLsa == 0) || (destLsa == 0)) {
    return -1;
  }

  double srcRadius = srcLsa->getCorRadius();
  double srcTheta = srcLsa->getCorTheta();
  double destRadius = destLsa->getCorRadius();
  double destTheta = destLsa->getCorTheta();

  double diffTheta = fabs(srcTheta - destTheta);
  if (diffTheta > MATH_PI) {
    diffTheta = 2 * MATH_PI - diffTheta;
  }
  if (srcRadius != -1 && destRadius != -1) {
    if (diffTheta == 0) {
      distance = fabs(srcRadius - destRadius);
    }
    else {
      distance = acosh((cosh(srcRadius) * cosh(destRadius)) -
                       (sinh(srcRadius) * sinh(destRadius) * cos(diffTheta)));
    }
  }
  else {
    distance = -1;
  }
  return distance;
}

void
HypRoutingTableCalculator::allocateNexthopRouters()
{
  m_nexthopRouters = new uint32_t[vNoLink];
}

void
HypRoutingTableCalculator::allocateDistanceToNeighbor()
{
  m_distanceToNeighbor = new double[vNoLink];
}

void
HypRoutingTableCalculator::allocateDistFromNbrToDest()
{
  m_distFromNbrToDest = new double[vNoLink];
}

void
HypRoutingTableCalculator::freeNexthopRouters()
{
  delete [] m_nexthopRouters;
}

void
HypRoutingTableCalculator::freeDistanceToNeighbor()
{
  delete [] m_distanceToNeighbor;
}

void
HypRoutingTableCalculator::freeDistFromNbrToDest()
{
  delete [] m_distFromNbrToDest;
}

}//namespace nlsr