/*
 *  Open BEAGLE
 *  Copyright (C) 2001-2005 by Christian Gagne and Marc Parizeau
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library 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
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 *  Contact:
 *  Laboratoire de Vision et Systemes Numeriques
 *  Departement de genie electrique et de genie informatique
 *  Universite Laval, Quebec, Canada, G1K 7P4
 *  http://vision.gel.ulaval.ca
 *
 */

/*!
 *  \file   beagle/GP/src/MutationSwapSubtreeOp.cpp
 *  \brief  Source code of class GP::MutationSwapSubtreeOp.
 *  \author Christian Gagne <cgagne@gmail.com>
 *  \author Jianjun Hu <hujianju@msu.edu>
 *  \author Marc Parizeau <parizeau@gel.ulaval.ca>
 *  $Revision: 1.11 $
 *  $Date: 2005/10/04 16:25:10 $
 */

#include "beagle/GP.hpp"

#include <algorithm>
#include <string>

using namespace Beagle;


/*!
 *  \brief Construct a GP swap subtree mutation operator.
 *  \param inMutationPbName Mutation probability parameter name used in register.
 *  \param inDistribPbName Swap mutation distribution probability parameter name.
 *  \param inName Name of the operator.
 */
GP::MutationSwapSubtreeOp::MutationSwapSubtreeOp(Beagle::string inMutationPbName,
                                                 Beagle::string inDistribPbName,
                                                 Beagle::string inName) :
  Beagle::MutationOp(inMutationPbName, inName),
  mDistribPbName(inDistribPbName)
{ }


/*!
 *  \brief Initialize the GP swap subtree mutation operator.
 *  \param ioSystem System of the evolution.
 */
void GP::MutationSwapSubtreeOp::initialize(Beagle::System& ioSystem)
{
  Beagle_StackTraceBeginM();
  Beagle::MutationOp::initialize(ioSystem);
  if(ioSystem.getRegister().isRegistered(mMutationPbName)) {
    ioSystem.getRegister().deleteEntry(mMutationPbName);
  }

  if(ioSystem.getRegister().isRegistered(mMutationPbName)) {
    mMutationProba = castHandleT<Float>(ioSystem.getRegister()[mMutationPbName]);
  } else {
    mMutationProba = new Float(float(0.0));
    string lLongDescrip = "Swap subtree mutation probability for an individual. ";
    lLongDescrip += "A swap subtree mutation consists to swap two subtrees of a tree in an ";
    lLongDescrip += "individual.";
    Register::Description lProbaDescription(
      "Swap subtree mutation prob.",
      "Float",
      "0.0",
      lLongDescrip
    );
    ioSystem.getRegister().addEntry(mMutationPbName, mMutationProba, lProbaDescription);
  }

  if(ioSystem.getRegister().isRegistered(mDistribPbName)) {
    mDistributionProba = castHandleT<Float>(ioSystem.getRegister()[mDistribPbName]);
  } else {
    mDistributionProba = new Float(float(0.5));
    string lLongDescrip = "Probability that a swap subtree is internal ";
    lLongDescrip += "(the mutation occurs between three points, where the 2nd point is in the ";
    lLongDescrip += "1st point's subtree, and the 3rd point is in the 2nd point's subtree) vs ";
    lLongDescrip += "being external (the mutation occurs between two points, ";
    lLongDescrip += "where both points are not within the other's subtree). ";
    lLongDescrip += "Value of 1.0 means that the swap subtrees mutations are all internal ";
    lLongDescrip += "while value of 0.0 means that swap subtrees mutations are all external.";
    Register::Description lDescription(
      "Swap subtree mut. distrib. prob.",
      "Float",
      "0.5",
      lLongDescrip
    );
    ioSystem.getRegister().addEntry(mDistribPbName, mDistributionProba, lDescription);
  }

  if(ioSystem.getRegister().isRegistered("gp.tree.maxdepth")) {
    mMaxTreeDepth = castHandleT<UInt>(ioSystem.getRegister()["gp.tree.maxdepth"]);
  } else {
    mMaxTreeDepth = new UInt(17);
    Register::Description lDescription(
      "Maximum tree depth",
      "UInt",
      "17",
      "Maximum allowed depth for the trees."
    );
    ioSystem.getRegister().addEntry("gp.tree.maxdepth", mMaxTreeDepth, lDescription);
  }

  if(ioSystem.getRegister().isRegistered("gp.try")) {
    mNumberAttempts = castHandleT<UInt>(ioSystem.getRegister()["gp.try"]);
  } else {
    mNumberAttempts = new UInt(2);
    string lLongDescrip = "Maximum number of attempts to modify a GP tree in a genetic ";
    lLongDescrip += "operation. As there is topological constraints on GP trees (i.e. tree ";
    lLongDescrip += "depth limit), it is often necessary to try a genetic operation several times.";
    Register::Description lDescription(
      "Max number of attempts",
      "UInt",
      "2",
      lLongDescrip
    );
    ioSystem.getRegister().addEntry("gp.try", mNumberAttempts, lDescription);
  }
  Beagle_StackTraceEndM("void GP::MutationSwapSubtreeOp::initialize(Beagle::System& ioSystem)");
}


/*!
 *  \brief Swap subtree mutate a GP individual.
 *  \param ioIndividual GP individual to swap subtree mutate.
 *  \param ioContext Context of the evolution.
 */
bool GP::MutationSwapSubtreeOp::mutate(Beagle::Individual& ioIndividual, Beagle::Context& ioContext)
{
  Beagle_StackTraceBeginM();
  // Initial parameters checks.
  Beagle_AssertM(ioIndividual.size() > 0);
  Beagle_ValidateParameterM(mNumberAttempts->getWrappedValue()>0, "gp.try", ">0");

  // Cast method arguments.
  GP::Individual&     lGPIndiv      = castObjectT<GP::Individual&>(ioIndividual);
  GP::Context&        lContext1     = castObjectT<GP::Context&>(ioContext);
  GP::Context::Alloc& lContextAlloc =
    castObjectT<GP::Context::Alloc&>(ioContext.getSystem().getContextAllocator());
  GP::Context::Handle lContextHdl2  = castHandleT<GP::Context>(lContextAlloc.clone(lContext1));

  // Get parameters in local values, with the total number of nodes of the mutated individual.
  bool             lMatingDone     = false;
  float            lDistrProba     = mDistributionProba->getWrappedValue();
  unsigned int     lMaxTreeDepth   = mMaxTreeDepth->getWrappedValue();
  GP::Tree::Handle lOldTreeHandle1 = lContext1.getGenotypeHandle();
  unsigned int     lOldTreeIndex1  = lContext1.getGenotypeIndex();
  unsigned int     lSizeIndiv      = 0;
  for(unsigned int i=0; i<lGPIndiv.size(); ++i) lSizeIndiv += lGPIndiv[i]->size();

  // Some outputs.
  Beagle_LogDebugM(
    lContext1.getSystem().getLogger(),
    "mutation", "Beagle::GP::MutationSwapSubtreeOp",
    string("Individual tried for swap subtree mutation (before): ")+
    lGPIndiv.serialize()
  );

  // Mutation loop. Try the given number of attempts to mutation the individual.
  for(unsigned int lAttempt=0; lAttempt < mNumberAttempts->getWrappedValue(); lAttempt++) {

    // Calculate the number of nodes in the individual
    unsigned int lNbNodes = 0;
    for(unsigned int i=0; i<lGPIndiv.size(); i++) lNbNodes += lGPIndiv[i]->size();
    if(lNbNodes == 0) return false;

    // Choose a node of the individual to mutate.
    unsigned int lNode1 = lContext1.getSystem().getRandomizer().rollInteger(0, lNbNodes-1);      

    // Get the tree in which the choosen node is. Change the global node index to the tree's index.
    unsigned int lChoosenTree = 0;
    for(; lChoosenTree<lGPIndiv.size(); ++lChoosenTree) {
      if(lNode1 < lGPIndiv[lChoosenTree]->size()) break;
      Beagle_AssertM(lNode1 >= lGPIndiv[lChoosenTree]->size());
      lNode1 -= lGPIndiv[lChoosenTree]->size();
    }
    Beagle_AssertM(lChoosenTree < lGPIndiv.size());

    // Cannot do anything with an tree of size <= 1.
    if(lGPIndiv[lChoosenTree]->size() <= 1) continue;

    // Some outputs.
    Beagle_LogVerboseM(
      lContext1.getSystem().getLogger(),
      "mutation", "Beagle::GP::MutationSwapSubtreeOp",
      string("Trying a swap subtree mutation of the ")+uint2ordinal(lChoosenTree+1)+
      string(" tree")
    );

    // Make two clones of the choosen tree.
    GP::Tree::Alloc& lTreeAlloc  = castObjectT<GP::Tree::Alloc&>(*lGPIndiv.getTypeAlloc());
    GP::Tree::Handle lTreeClone1 = castHandleT<GP::Tree>(lTreeAlloc.clone(*lGPIndiv[lChoosenTree]));
    GP::Tree::Handle lTreeClone2 = castHandleT<GP::Tree>(lTreeAlloc.clone(*lGPIndiv[lChoosenTree]));

    // Now we decide whether the swap subtree mutation is internal or external.
    bool lMutationType = lContext1.getSystem().getRandomizer().rollUniform(0.0, 1.0) < lDistrProba;

    // Cannot do an internal mutation when there is only one branch in the tree.
    if(lTreeClone1->size() == (*lTreeClone1)[0].mPrimitive->getNumberArguments()+1)
      lMutationType = false;

    // This is special case, a linear tree. Cannot do an external mutation.
    if(lTreeClone1->size() == (*lTreeClone1)[1].mSubTreeSize+1) {
      if(lTreeClone1->size()==2) continue;   // Cannot do anything here with the tree.
      lMutationType = true;
    }

    // lMutationType is true -> internal mutation
    if(lMutationType)  {

      // If the selected node is a terminal, or a branch with a subtree made only of terminals,
      // choose another node in the same tree.
      while((*lTreeClone1)[lNode1].mSubTreeSize ==
            ((*lTreeClone1)[lNode1].mPrimitive->getNumberArguments()+1)) {
        lNode1 = lContext1.getSystem().getRandomizer().rollInteger(0, lTreeClone1->size()-1);
      }

      // Choosing the second node, a branch in lNode1's subtree.
      unsigned int lSubTreeSizeN1 = (*lTreeClone1)[lNode1].mSubTreeSize;
      unsigned int lN2OffN1 =
        lContext1.getSystem().getRandomizer().rollInteger(1, lSubTreeSizeN1-1);
      unsigned int lNode2 = lNode1 + lN2OffN1;
      while((*lTreeClone1)[lNode2].mPrimitive->getNumberArguments() == 0) {
        lN2OffN1 = lContext1.getSystem().getRandomizer().rollInteger(1, lSubTreeSizeN1-1);
        lNode2 = lNode1 + lN2OffN1;
      }

      // Choosing the third node, any node in lNode2's subtree.
      unsigned int lSubTreeSizeN2 = (*lTreeClone1)[lNode2].mSubTreeSize;
      unsigned int lN3OffN2 =
        lContext1.getSystem().getRandomizer().rollInteger(1, lSubTreeSizeN2-1);

      // Ok, now we can exchange the subtrees.

      // New value of lNode1 and lNode2 for the second exchange.
      unsigned int lNode3Exch2 = lNode1 + lN3OffN2;
      unsigned int lNode1Exch2 = lNode2;

      // New value of lNode1 and lNode2 for the third exchange.
      unsigned int lNode2Exch3 = lNode1 + lN3OffN2 + lN2OffN1;
      unsigned int lNode3Exch3 = lNode2;
 
      // First exchange.
      lTreeClone1->setContextToNode(lNode1, lContext1);
      lTreeClone2->setContextToNode(lNode2, *lContextHdl2);
      exchangeSubTrees(*lTreeClone1, lNode1, lContext1,
                       *lTreeClone2, lNode2, *lContextHdl2);

      // Second exchange.
      lTreeClone1->setContextToNode(lNode3Exch2, lContext1);
      lTreeClone2->setContextToNode(lNode1Exch2, *lContextHdl2);
      exchangeSubTrees(*lTreeClone1, lNode3Exch2, lContext1,
                       *lTreeClone2, lNode1Exch2, *lContextHdl2);

      // Third exchange.
      lTreeClone1->setContextToNode(lNode2Exch3, lContext1);
      lTreeClone2->setContextToNode(lNode3Exch3, *lContextHdl2);
      exchangeSubTrees(*lTreeClone1, lNode2Exch3, lContext1,
                       *lTreeClone2, lNode3Exch3, *lContextHdl2);

      // Checking if the tree depth is respected. If not, start again.
      if(lTreeClone1->getTreeDepth() > lMaxTreeDepth) {
        Beagle_LogVerboseM(
          lContext1.getSystem().getLogger(),
          "mutation", "Beagle::GP::MutationSwapSubtreeOp",
          "Tree maximum depth exceeded. GP swap subtree mutation invalid."
        );
        continue;
      }

      lGPIndiv[lChoosenTree] = lTreeClone1;
      Beagle_LogVerboseM(
        lContext1.getSystem().getLogger(),
        "mutation", "Beagle::GP::MutationSwapSubtreeOp",
        "GP swap subtree mutation valid"
      );
      lMatingDone = true;
      break;   // The swap subtree mutation is valid.
    }

    // lMutationType is false -> external mutation
    else {

      // Deterniming the minimal node index to use.
      unsigned int lMinNodeIndex = 0;
      for(; lTreeClone1->size() == ((*lTreeClone1)[lMinNodeIndex].mSubTreeSize+lMinNodeIndex);
          ++lMinNodeIndex) {
        if(lMinNodeIndex == (lTreeClone1->size()-1)) continue; // Can't do anything with linear tree.
      }

      // Change lNode1 if less than minimum node index.
      if(lNode1 < lMinNodeIndex)
        lNode1 = lContext1.getSystem().getRandomizer().rollInteger(lMinNodeIndex,
                                                                   lTreeClone1->size()-1);

      // Choosing second swap subtree mutation point.
      std::vector< unsigned int,BEAGLE_STLALLOCATOR<unsigned int> > lValidN2;
      for(unsigned int i=lMinNodeIndex; i<lTreeClone1->size(); ++i) {
        if((i>=lNode1) && (i<lNode1+(*lTreeClone1)[lNode1].mSubTreeSize)) continue;
        else if((lNode1>=i) && (lNode1<(i+(*lTreeClone1)[i].mSubTreeSize))) continue;
        else lValidN2.push_back(i);
      }
      unsigned int lNode2 =
        lValidN2[lContext1.getSystem().getRandomizer().rollInteger(0, lValidN2.size()-1)];

      Beagle_LogVerboseM(
        lContext1.getSystem().getLogger(),
        "mutation", "Beagle::GP::MutationSwapSubtreeOp",
        string("Trying an external swap subtree mutation of the ")+uint2ordinal(lNode1+1)+
        string(" node with the subtree to the ")+uint2ordinal(lNode2+1)+
        string(" node")
      );

      // Ok, now we can exchange the subtrees.

      // New value of lNode1 and lNode2 for the second exchange.
      unsigned int lNode1Exch2 = lNode1;
      unsigned int lNode2Exch2 = lNode2;
      if(lNode1 < lNode2) {
        lNode2Exch2 += (*lTreeClone1)[lNode2].mSubTreeSize;
        lNode2Exch2 -= (*lTreeClone1)[lNode1].mSubTreeSize;
      }
      else {
        lNode1Exch2 += (*lTreeClone1)[lNode1].mSubTreeSize;
        lNode1Exch2 -= (*lTreeClone1)[lNode2].mSubTreeSize;
      }

      // First exchange.
      lTreeClone1->setContextToNode(lNode1, lContext1);
      lTreeClone2->setContextToNode(lNode2, *lContextHdl2);
      exchangeSubTrees(*lTreeClone1, lNode1, lContext1,
                       *lTreeClone2, lNode2, *lContextHdl2);

      // Second exchange.
      lTreeClone1->setContextToNode(lNode2Exch2, lContext1);
      lTreeClone2->setContextToNode(lNode1Exch2, *lContextHdl2);
      exchangeSubTrees(*lTreeClone1, lNode2Exch2, lContext1,
                       *lTreeClone2, lNode1Exch2, *lContextHdl2);

      // Checking if the tree depth is respected. If not, start again.
      if(lTreeClone1->getTreeDepth() > lMaxTreeDepth) {
        Beagle_LogVerboseM(
          lContext1.getSystem().getLogger(),
          "mutation", "Beagle::GP::MutationSwapSubtreeOp",
          "Tree maximum depth exceeded. GP swap subtree mutation invalid."
        );
        continue;
      }

      lGPIndiv[lChoosenTree] = lTreeClone1;
      Beagle_LogVerboseM(
        lContext1.getSystem().getLogger(),
        "mutation", "Beagle::GP::MutationSwapSubtreeOp",
        "GP swap subtree mutation valid"
      );
      lMatingDone = true;
      break;   // The swap subtree mutation is valid.
    }
  }

  // Replace the contexts.
  lContext1.setGenotypeHandle(lOldTreeHandle1);
  lContext1.setGenotypeIndex(lOldTreeIndex1);

  if(lMatingDone) {
    Beagle_LogDebugM(
      lContext1.getSystem().getLogger(),
      "mutation", "Beagle::GP::MutationSwapSubtreeOp",
      string("Individual after swap subtree mutation: ")+
      lGPIndiv.serialize()
    );
  }
  else {
    Beagle_LogVerboseM(
      lContext1.getSystem().getLogger(),
      "mutation", "Beagle::GP::MutationSwapSubtreeOp",
      "No GP swap subtree mutation done"
    );
  }

  return lMatingDone;
  Beagle_StackTraceEndM("bool GP::MutationSwapSubtreeOp::mutate(Beagle::Individual& ioIndividual, Beagle::Context& ioContext)");
}


/*!
 *  \brief  Exchange two GP trees on given points.
 *  \param  ioTree1 First tree to mate.
 *  \param  inNode1 Node index of the swap subtree first point.
 *  \param  ioContext1 Evolutionary context relatively to the first tree.
 *  \param  ioTree2 Second tree to mate.
 *  \param  inNode2 Node index of the swap subtree second point.
 *  \param  ioContext2 Evolutionary context relatively to the second tree.
 */
void GP::MutationSwapSubtreeOp::exchangeSubTrees(GP::Tree& ioTree1,
                                                 unsigned int inNode1,
                                                 GP::Context& ioContext1,
                                                 GP::Tree& ioTree2,
                                                 unsigned int inNode2,
                                                 GP::Context& ioContext2)
{
  Beagle_StackTraceBeginM();
  Beagle_AssertM(&ioTree1 != &ioTree2);
  unsigned int lSwapSize1 = ioTree1[inNode1].mSubTreeSize;
  unsigned int lSwapSize2 = ioTree2[inNode2].mSubTreeSize;
  if(lSwapSize1 <= lSwapSize2) {
    std::swap_ranges(ioTree1.begin()+inNode1, ioTree1.begin()+inNode1+lSwapSize1, ioTree2.begin()+inNode2);
    ioTree1.insert(ioTree1.begin()+inNode1+lSwapSize1,
                   ioTree2.begin()+inNode2+lSwapSize1,
                   ioTree2.begin()+inNode2+lSwapSize2);
    ioTree2.erase(ioTree2.begin()+inNode2+lSwapSize1, ioTree2.begin()+inNode2+lSwapSize2);
  }
  else {
    std::swap_ranges(ioTree1.begin()+inNode1, ioTree1.begin()+inNode1+lSwapSize2, ioTree2.begin()+inNode2);
    ioTree2.insert(ioTree2.begin()+inNode2+lSwapSize2,
                   ioTree1.begin()+inNode1+lSwapSize2,
                   ioTree1.begin()+inNode1+lSwapSize1);
    ioTree1.erase(ioTree1.begin()+inNode1+lSwapSize2, ioTree1.begin()+inNode1+lSwapSize1);
  }
  int lDiffSize = lSwapSize1 - lSwapSize2;
  for(unsigned int i=0; i<(ioContext1.getCallStackSize()-1); i++)
    ioTree1[ioContext1.getCallStackElement(i)].mSubTreeSize -= lDiffSize;
  for(unsigned int j=0; j<(ioContext2.getCallStackSize()-1); j++)
    ioTree2[ioContext2.getCallStackElement(j)].mSubTreeSize += lDiffSize;
  Beagle_StackTraceEndM("void GP::MutationSwapSubtreeOp::exchangeSubTrees(GP::Tree& ioTree1, unsigned int inNode1, GP::Context& ioContext1, GP::Tree& ioTree2, unsigned int inNode2, GP::Context& ioContext2)");
}


/*!
 *  \brief Read a mutation operator from XML subtree.
 *  \param inIter XML iterator to use to read crossover operator.
 *  \param inOpMap Operator map to use to read crossover operator.
 */
void GP::MutationSwapSubtreeOp::readWithMap(PACC::XML::ConstIterator inIter, OperatorMap& inOpMap)
{
  Beagle_StackTraceBeginM();
  if((inIter->getType()!=PACC::XML::eData) || (inIter->getValue()!=getName().c_str())) {
    std::ostringstream lOSS;
    lOSS << "tag <" << getName() << "> expected!" << std::flush;
    throw Beagle_IOExceptionNodeM(*inIter, lOSS.str().c_str());
  }
  string mMutationPbReadName = inIter->getAttribute("mutationpb").c_str();
  if(mMutationPbReadName.empty() == false) mMutationPbName = mMutationPbReadName;  
  string mDistribPbReadName = inIter->getAttribute("distrpb").c_str();
  if(mDistribPbReadName.empty() == false) mDistribPbName = mDistribPbReadName;
  Beagle_StackTraceEndM("void GP::MutationSwapSubtreeOp::readWithMap(PACC::XML::ConstIterator inIter, OperatorMap& inOpMap)");
}


/*!
 *  \brief Write mutation operator into XML streamer.
 *  \param ioStreamer XML streamer to write mutation operator into.
 *  \param inIndent Whether XML output should be indented.
 */
void GP::MutationSwapSubtreeOp::writeContent(PACC::XML::Streamer& ioStreamer, bool inIndent) const
{
  Beagle_StackTraceBeginM();
  Beagle::MutationOp::writeContent(ioStreamer, inIndent);
  ioStreamer.insertAttribute("distrpb", mDistribPbName);
  Beagle_StackTraceEndM("void GP::MutationSwapSubtreeOp::writeContent(PACC::XML::Streamer& ioStreamer, bool inIndent) const");
}