/********************************************************************
 * AUTHORS: Vijay Ganesh, Trevor Hansen
 *
 * BEGIN DATE: November, 2005
 *
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
********************************************************************/

#include "stp/AST/AST.h"
#include "stp/AbsRefineCounterExample/AbsRefine_CounterExample.h"
#include "stp/STPManager/STPManager.h"
#include <cassert>
#include <math.h>

namespace stp
{
using std::pair;
using std::map;

/******************************************************************
 * Abstraction Refinement related functions
 ******************************************************************/

enum Polarity
{
  LEFT_ONLY,
  RIGHT_ONLY,
  BOTH
};

void getSatVariables(const ASTNode& a, vector<unsigned>& v_a,
                     SATSolver& SatSolver, ToSATBase::ASTNodeToSATVar& satVar)
{
  ToSATBase::ASTNodeToSATVar::iterator it = satVar.find(a);
  if (it != satVar.end())
    v_a = it->second;
  else if (!a.isConstant())
  {
    assert(a.GetKind() == SYMBOL);
    // It was ommitted from the initial problem, so assign it freshly.
    for (unsigned i = 0; i < a.GetValueWidth(); i++)
    {
      uint32_t v = SatSolver.newVar();
      // We probably don't want the variable eliminated.
      SatSolver.setFrozen(v);
      v_a.push_back(v);
    }
    satVar.insert(make_pair(a, v_a));
  }
}

// This function adds the clauses to constrain that "a" and "b" equal a fresh
// variable
// (which it returns).
// Because it's used to create array axionms (a=b)-> (c=d), it can be
// used to only add one of the two polarities.
Minisat::Var getEquals(SATSolver& SatSolver, const ASTNode& a, const ASTNode& b,
                       ToSATBase::ASTNodeToSATVar& satVar,
                       Polarity polary = BOTH)
{
  const unsigned width = a.GetValueWidth();
  assert(width == b.GetValueWidth());
  assert(!a.isConstant() || !b.isConstant());

  vector<unsigned> v_a;
  vector<unsigned> v_b;

  getSatVariables(a, v_a, SatSolver, satVar);
  getSatVariables(b, v_b, SatSolver, satVar);

  // The only time v_a or v_b will be empty is if "a" resp. "b" is a constant.

  if (v_a.size() == width && v_b.size() == width)
  {
    SATSolver::vec_literals all;
    const int result = SatSolver.newVar();

    for (unsigned i = 0; i < width; i++)
    {
      SATSolver::vec_literals s;

      if (polary != RIGHT_ONLY)
      {
        int nv0 = SatSolver.newVar();
        s.push(SATSolver::mkLit(v_a[i], true));
        s.push(SATSolver::mkLit(v_b[i], true));
        s.push(SATSolver::mkLit(nv0, false));
        SatSolver.addClause(s);
        s.clear();

        s.push(SATSolver::mkLit(v_a[i], false));
        s.push(SATSolver::mkLit(v_b[i], false));
        s.push(SATSolver::mkLit(nv0, false));
        SatSolver.addClause(s);
        s.clear();

        all.push(SATSolver::mkLit(nv0, true));
      }

      if (polary != LEFT_ONLY)
      {
        s.push(SATSolver::mkLit(v_a[i], true));
        s.push(SATSolver::mkLit(v_b[i], false));
        s.push(SATSolver::mkLit(result, true));
        SatSolver.addClause(s);
        s.clear();

        s.push(SATSolver::mkLit(v_a[i], false));
        s.push(SATSolver::mkLit(v_b[i], true));
        s.push(SATSolver::mkLit(result, true));
        SatSolver.addClause(s);
        s.clear();
      }
    }
    if (all.size() > 0)
    {
      all.push(SATSolver::mkLit(result, false));
      SatSolver.addClause(all);
    }
    return result;
  }
  else if ((v_a.size() == 0) ^ (v_b.size() == 0))
  {
    ASTNode constant = a.isConstant() ? a : b;
    vector<unsigned> vec = v_a.size() == 0 ? v_b : v_a;
    assert(constant.isConstant());
    assert(vec.size() == width);

    SATSolver::vec_literals all;
    const int result = SatSolver.newVar();
    all.push(SATSolver::mkLit(result, false));

    CBV v = constant.GetBVConst();
    for (unsigned i = 0; i < width; i++)
    {
      if (polary != RIGHT_ONLY)
      {
        if (CONSTANTBV::BitVector_bit_test(v, i))
          all.push(SATSolver::mkLit(vec[i], true));
        else
          all.push(SATSolver::mkLit(vec[i], false));
      }

      if (polary != LEFT_ONLY)
      {
        SATSolver::vec_literals p;
        p.push(SATSolver::mkLit(result, true));
        if (CONSTANTBV::BitVector_bit_test(v, i))
          p.push(SATSolver::mkLit(vec[i], false));
        else
          p.push(SATSolver::mkLit(vec[i], true));

        SatSolver.addClause(p);
      }
    }
    if (all.size() > 1)
      SatSolver.addClause(all);
    return result;
  }
  else
  {
    FatalError("Unexpected, both must be constants..");
  }
}

/******************************************************************
 * ARRAY READ ABSTRACTION REFINEMENT
 *
 * SATBased_ArrayReadRefinement()
 *
 * What it really does is, for each array, loop over each index i.
 * inside that loop, it finds all the true and false axioms with i
 * as first index.  When it's got them all, it adds the false axioms
 * to the formula and re-solves, and returns if the result is
 * correct.  Otherwise, it goes on to the next index.
 *
 * If it gets through all the indices without a correct result
 * (which I think is impossible), it then solves with all the true
 * axioms, too.
 *
 * This is not the most obvious way to do it, and I don't know how
 * it compares with other approaches (e.g., one false axiom at a
 * time or all the false axioms each time).
 *****************************************************************/
struct AxiomToBe
{
  AxiomToBe(ASTNode i0, ASTNode i1, ASTNode v0, ASTNode v1)
  {
    index0 = i0;
    index1 = i1;
    value0 = v0;
    value1 = v1;
  }
  ASTNode index0, index1;
  ASTNode value0, value1;

  int numberOfConstants() const
  {
    return ((index0.isConstant() ? 1 : 0) + (index1.isConstant() ? 1 : 0) +
            (index0.isConstant() ? 1 : 0) + (index1.isConstant() ? 1 : 0));
  }
};

void applyAxiomToSAT(SATSolver& SatSolver, AxiomToBe& toBe,
                     ToSATBase::ASTNodeToSATVar& satVar)
{
  Minisat::Var a =
      getEquals(SatSolver, toBe.index0, toBe.index1, satVar, LEFT_ONLY);
  Minisat::Var b =
      getEquals(SatSolver, toBe.value0, toBe.value1, satVar, RIGHT_ONLY);
  SATSolver::vec_literals satSolverClause;
  satSolverClause.push(SATSolver::mkLit(a, true));
  satSolverClause.push(SATSolver::mkLit(b, false));
  SatSolver.addClause(satSolverClause);
}

void applyAxiomsToSolver(ToSATBase::ASTNodeToSATVar& satVar,
                         vector<AxiomToBe>& toBe, SATSolver& SatSolver)
{
  for (size_t i = 0; i < toBe.size(); i++)
  {
    applyAxiomToSAT(SatSolver, toBe[i], satVar);
  }
  toBe.clear();
}

bool sortBySize(const pair<ASTNode, ArrayTransformer::arrTypeMap>& a,
                const pair<ASTNode, ArrayTransformer::arrTypeMap>& b)
{
  return a.second.size() < b.second.size();
}

bool sortByIndexConstants(const pair<ASTNode, ArrayTransformer::ArrayRead>& a,
                          const pair<ASTNode, ArrayTransformer::ArrayRead>& b)
{
  int aCount = ((a.second.index_symbol.isConstant()) ? 2 : 0) +
               (a.second.symbol.isConstant() ? 1 : 0);
  int bCount = ((b.second.index_symbol.isConstant()) ? 2 : 0) +
               (b.second.symbol.isConstant() ? 1 : 0);
  return aCount > bCount;
}

bool sortbyConstants(const AxiomToBe& a, const AxiomToBe& b)
{
  return a.numberOfConstants() > b.numberOfConstants();
}

SOLVER_RETURN_TYPE
AbsRefine_CounterExample::SATBased_ArrayReadRefinement(
    SATSolver& SatSolver, const ASTNode& original_input, ToSATBase* tosat)
{
  vector<AxiomToBe> RemainingAxiomsVec;
  vector<AxiomToBe> FalseAxiomsVec;
  // NB. Because we stop this timer before entering the SAT solver, the count
  // it produces isn't the number of times Array Read Refinement was entered.
  bm->GetRunTimes()->start(RunTimes::ArrayReadRefinement);
  /// Check the arrays with the least indexes first.

  vector<pair<ASTNode, ArrayTransformer::arrTypeMap>> arrayToIndex;
  arrayToIndex.insert(arrayToIndex.begin(),
                      ArrayTransform->arrayToIndexToRead.begin(),
                      ArrayTransform->arrayToIndexToRead.end());
  sort(arrayToIndex.begin(), arrayToIndex.end(), sortBySize);

  // In these loops we try to construct Leibnitz axioms and add it to
  // the solve(). We add only those axioms that are false in the
  // current counterexample. we keep adding the axioms until there
  // are no more axioms to add
  //
  // for each array, fetch its list of indices seen so far
  for (vector<pair<ASTNode, ArrayTransformer::arrTypeMap>>::const_iterator
           iset = arrayToIndex.begin(),
           iset_end = arrayToIndex.end();
       iset != iset_end; iset++)
  {
    const map<ASTNode, ArrayTransformer::ArrayRead>& mapper = iset->second;

    vector<ASTNode> listOfIndices;
    listOfIndices.reserve(mapper.size());

    // Make a vector of the read symbols.
    ASTVec read_node_symbols;
    read_node_symbols.reserve(listOfIndices.size());

    vector<Kind> jKind;
    jKind.reserve(mapper.size());

    vector<ASTNode> concreteIndexes;
    concreteIndexes.reserve(mapper.size());

    vector<ASTNode> concreteValues;
    concreteValues.reserve(mapper.size());

    ASTVec index_symbols;

    vector<pair<ASTNode, ArrayTransformer::ArrayRead>> indexToRead;
    indexToRead.insert(indexToRead.begin(), mapper.begin(), mapper.end());
    sort(indexToRead.begin(), indexToRead.end(), sortByIndexConstants);

    for (vector<pair<ASTNode, ArrayTransformer::ArrayRead>>::const_iterator it =
             indexToRead.begin();
         it != indexToRead.end(); it++)
    {
      const ASTNode& the_index = it->first;
      listOfIndices.push_back(the_index);

      ASTNode arrsym = it->second.symbol;
      read_node_symbols.push_back(arrsym);

      index_symbols.push_back(it->second.index_symbol);

      assert(read_node_symbols[0].GetValueWidth() == arrsym.GetValueWidth());
      assert(listOfIndices[0].GetValueWidth() == the_index.GetValueWidth());

      jKind.push_back(the_index.GetKind());

      concreteIndexes.push_back(TermToConstTermUsingModel(the_index));
      concreteValues.push_back(TermToConstTermUsingModel(arrsym));
    }

    assert(listOfIndices.size() == mapper.size());

    // loop over the list of indices for the array and create LA,
    // and add to inputAlreadyInSAT
    for (size_t i = 0; i < listOfIndices.size(); i++)
    {
      const ASTNode& index_i = listOfIndices[i];
      const Kind iKind = index_i.GetKind();

      // Create all distinct pairs of indexes.
      for (size_t j = i + 1; j < listOfIndices.size(); j++)
      {
        const ASTNode& index_j = listOfIndices[j];

        // If the index is a constant, and different, then there's no reason to
        // check.
        // Sometimes we get the same index stored multiple times in the array.
        // Not sure why...
        if (BVCONST == iKind && jKind[j] == BVCONST && index_i != index_j)
          continue;

        if (ASTFalse == simp->CreateSimplifiedEQ(index_i, index_j))
          continue; // shortcut.

        AxiomToBe o(index_symbols[i], index_symbols[j], read_node_symbols[i],
                    read_node_symbols[j]);

        if (concreteIndexes[i] == concreteIndexes[j] &&
            concreteValues[i] != concreteValues[j])
        {
          FalseAxiomsVec.push_back(o);
          // ToSATBase::ASTNodeToSATVar	& satVar =
          // tosat->SATVar_to_SymbolIndexMap();
          // applyAxiomsToSolver(satVar, FalseAxiomsVec, SatSolver);
        }
        else
          RemainingAxiomsVec.push_back(o);
      }
      if (FalseAxiomsVec.size() > 0)
      {
        ToSATBase::ASTNodeToSATVar& satVar = tosat->SATVar_to_SymbolIndexMap();
        applyAxiomsToSolver(satVar, FalseAxiomsVec, SatSolver);

        SOLVER_RETURN_TYPE res2;
        bm->GetRunTimes()->stop(RunTimes::ArrayReadRefinement);
        res2 = CallSAT_ResultCheck(SatSolver, ASTTrue, original_input, tosat,
                                   true);

        if (SOLVER_UNDECIDED != res2)
          return res2;
        bm->GetRunTimes()->start(RunTimes::ArrayReadRefinement);
      }
    }
  }
#if 1
  if (RemainingAxiomsVec.size() > 0)
  {
    if (bm->UserFlags.stats_flag)
    {
      std::cout << "Adding all the remaining " << RemainingAxiomsVec.size()
                << " read axioms " << std::endl;
    }
    ToSATBase::ASTNodeToSATVar& satVar = tosat->SATVar_to_SymbolIndexMap();
    applyAxiomsToSolver(satVar, RemainingAxiomsVec, SatSolver);

    bm->GetRunTimes()->stop(RunTimes::ArrayReadRefinement);
    return CallSAT_ResultCheck(SatSolver, ASTTrue, original_input, tosat, true);
  }
// For difficult problems, I suspec this is a better way to do it.
// However because it can cause an extra three SAT solver calls, it slows down
// easy problems.
#else
  if (RemainingAxiomsVec.size() > 0)
  {
    // Add the axioms in order of how many constants there are in each.

    ToSATBase::ASTNodeToSATVar& satVar = tosat->SATVar_to_SymbolIndexMap();
    sort(RemainingAxiomsVec.begin(), RemainingAxiomsVec.end(), sortbyConstants);
    int current_position = 0;
    for (int n_const = 4; n_const >= 0; n_const--)
    {
      bool added = false;
      while (current_position < RemainingAxiomsVec.size() &&
             RemainingAxiomsVec[current_position].numberOfConstants() ==
                 n_const)
      {
        AxiomToBe& toBe = RemainingAxiomsVec[current_position];
        applyAxiomToSAT(SatSolver, toBe, satVar);
        current_position++;
        added = true;
      }
      if (!added)
        continue;
      bm->GetRunTimes()->stop(RunTimes::ArrayReadRefinement);
      SOLVER_RETURN_TYPE res2;
      res2 =
          CallSAT_ResultCheck(SatSolver, ASTTrue, original_input, tosat, true);
      if (SOLVER_UNDECIDED != res2)
        return res2;

      bm->GetRunTimes()->start(RunTimes::ArrayReadRefinement);
    }
    assert(current_position == RemainingAxiomsVec.size());
    RemainingAxiomsVec.clear();
    assert(SOLVER_UNDECIDED == CallSAT_ResultCheck(SatSolver, ASTTrue,
                                                   original_input, tosat,
                                                   true));
  }
#endif

  bm->GetRunTimes()->stop(RunTimes::ArrayReadRefinement);
  return SOLVER_UNDECIDED;
}

// This is another way of performing Ackermannisation.
void AbsRefine_CounterExample::applyAllCongruenceConstraints(
    SATSolver& SatSolver, ToSATBase* tosat)
{
  // if (bm->UserFlags.stats_flag)
  std::cerr << "~CNF~" << std::endl;

  vector<pair<ASTNode, ArrayTransformer::arrTypeMap>> arrayToIndex;
  arrayToIndex.insert(arrayToIndex.begin(),
                      ArrayTransform->arrayToIndexToRead.begin(),
                      ArrayTransform->arrayToIndexToRead.end());

  ToSATBase::ASTNodeToSATVar& satVar = tosat->SATVar_to_SymbolIndexMap();

  // for each array, fetch its list of indices seen so far
  for (vector<pair<ASTNode, ArrayTransformer::arrTypeMap>>::const_iterator
           iset = arrayToIndex.begin(),
           iset_end = arrayToIndex.end();
       iset != iset_end; iset++)
  {
    // const ASTNode& ArrName = iset->first;
    const map<ASTNode, ArrayTransformer::ArrayRead>& mapper = iset->second;

    vector<ASTNode> listOfIndices;
    listOfIndices.reserve(mapper.size());

    // Make a vector of the read symbols.
    ASTVec read_node_symbols;
    read_node_symbols.reserve(listOfIndices.size());

    vector<Kind> jKind;
    jKind.reserve(mapper.size());

    ASTVec index_symbols;
    index_symbols.reserve(mapper.size());

    for (map<ASTNode, ArrayTransformer::ArrayRead>::const_iterator it =
             mapper.begin();
         it != mapper.end(); it++)
    {
      const ASTNode& the_index = it->first;
      listOfIndices.push_back(the_index);

      ASTNode arrsym = it->second.symbol;
      read_node_symbols.push_back(arrsym);

      index_symbols.push_back(it->second.index_symbol);

      assert(read_node_symbols[0].GetValueWidth() == arrsym.GetValueWidth());
      assert(listOfIndices[0].GetValueWidth() == the_index.GetValueWidth());

      jKind.push_back(the_index.GetKind());
    }

    assert(listOfIndices.size() == mapper.size());

    // loop over the list of indices for the array and create LA,
    // and add to inputAlreadyInSAT
    for (size_t i = 0; i < listOfIndices.size(); i++)
    {
      const ASTNode& index_i = listOfIndices[i];
      const Kind iKind = index_i.GetKind();

      // Create all distinct pairs of indexes.
      for (size_t j = i + 1; j < listOfIndices.size(); j++)
      {
        const ASTNode& index_j = listOfIndices[j];

        // If the index is a constant, and different, then there's no reason to
        // check.
        // Sometimes we get the same index stored multiple times in the array.
        // Not sure why...
        if (BVCONST == iKind && jKind[j] == BVCONST && index_i != index_j)
          continue;

        if (ASTFalse == simp->CreateSimplifiedEQ(index_i, index_j))
          continue; // shortcut.

        if (index_i == index_j)
          std::cerr << "EQUAL";

        AxiomToBe o(index_symbols[i], index_symbols[j], read_node_symbols[i],
                    read_node_symbols[j]);

        applyAxiomToSAT(SatSolver, o, satVar);
      }
    }
  }
}

} // end of namespace stp