/*
 *  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/MutationSwapSubtreeConstrainedOp.cpp
 *  \brief  Source code of class GP::MutationSwapSubtreeConstrainedOp.
 *  \author Christian Gagne <cgagne@gmail.com>
 *  \author Jianjun Hu <hujianju@msu.edu>
 *  \author Marc Parizeau <parizeau@gel.ulaval.ca>
 *  $Revision: 1.7 $
 *  $Date: 2005/10/04 16:25:10 $
 */

#include "beagle/GP.hpp"

#include <algorithm>
#include <string>

using namespace Beagle;


/*!
 *  \brief Construct a constrained 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::MutationSwapSubtreeConstrainedOp::MutationSwapSubtreeConstrainedOp(
    Beagle::string inMutationPbName,
    Beagle::string inDistribPbName,
    Beagle::string inName) :
  MutationSwapSubtreeOp(inMutationPbName, inDistribPbName, inName)
{ }


/*!
 *  \brief Swap subtree mutate a constrained GP individual.
 *  \param ioIndividual GP individual to swap subtree mutate.
 *  \param ioContext Context of the evolution.
 */
bool GP::MutationSwapSubtreeConstrainedOp::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::MutationSwapSubtreeConstrainedOp",
    string("Individual tried for constrained 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++) {

    // Choose a node of the individual to mutate.
    unsigned int lNode1 = lContext1.getSystem().getRandomizer().rollInteger(0, lGPIndiv.size()-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::MutationSwapSubtreeConstrainedOp",
      string("Trying a constrained 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::MutationSwapSubtreeConstrainedOp",
          "Tree maximum depth exceeded. Constrained GP swap subtree mutation invalid."
        );
        continue;
      }

      // As we are using topologically contrained tree, valid the new tree. If it is not valid,
      // do a new mutation attempt.
      lContext1.setGenotypeHandle(lTreeClone1);
      lContext1.setGenotypeIndex(lChoosenTree);
      lTreeClone1->setContextToNode(lNode1, lContext1);
      if(lTreeClone1->validateSubTree(lNode1, lContext1)) {
        lGPIndiv[lChoosenTree] = lTreeClone1;
        Beagle_LogVerboseM(
          lContext1.getSystem().getLogger(),
          "mutation", "Beagle::GP::MutationSwapSubtreeConstrainedOp",
          "Constrained GP swap subtree mutation valid"
        );
        lMatingDone = true;
        break; // The swap subtree mutation is valid.
      }
      else {
        Beagle_LogVerboseM(
          lContext1.getSystem().getLogger(),
          "mutation", "Beagle::GP::MutationSwapSubtreeConstrainedOp",
          "Constrained GP swap subtree mutation invalid"
        );
        continue;
      }
    }

    // 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::MutationSwapSubtreeConstrainedOp",
        string("Trying an external constrained 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::MutationSwapSubtreeConstrainedOp",
          "Tree maximum depth exceeded. Constrained GP swap subtree mutation invalid."
        );
        continue;
      }

      // As we are using topologically contrained tree, valid the new tree. If it is not valid,
      // do a new mutation attempt.
      lContext1.setGenotypeHandle(lTreeClone1);
      lContext1.setGenotypeIndex(lChoosenTree);
      lTreeClone1->setContextToNode(lNode1Exch2, lContext1);
      bool lNode1Valid = lTreeClone1->validateSubTree(lNode1Exch2,lContext1);
      lTreeClone1->setContextToNode(lNode2Exch2, lContext1);
      bool lNode2Valid = lTreeClone1->validateSubTree(lNode2Exch2,lContext1);        
      if(lNode1Valid && lNode2Valid) {
        lGPIndiv[lChoosenTree] = lTreeClone1;
        Beagle_LogVerboseM(
          lContext1.getSystem().getLogger(),
          "mutation", "Beagle::GP::MutationSwapSubtreeConstrainedOp",
          "Constrained GP swap subtree mutation valid"
        );
        lMatingDone = true;
        break; // The swap subtree mutation is valid.
      }
      else {
        Beagle_LogVerboseM(
          lContext1.getSystem().getLogger(),
          "mutation", "Beagle::GP::MutationSwapSubtreeConstrainedOp",
          "Constrained GP swap subtree mutation invalid"
        );
        continue;
      }
    }
  }

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

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

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