/*********************                                                        */
/*! \file ce_guided_instantiation.cpp
 ** \verbatim
 ** Top contributors (to current version):
 **   Andrew Reynolds, Tim King, Morgan Deters
 ** This file is part of the CVC4 project.
 ** Copyright (c) 2009-2017 by the authors listed in the file AUTHORS
 ** in the top-level source directory) and their institutional affiliations.
 ** All rights reserved.  See the file COPYING in the top-level source
 ** directory for licensing information.\endverbatim
 **
 ** \brief counterexample guided instantiation class
 **
 **/
#include "theory/quantifiers/ce_guided_instantiation.h"

#include "expr/datatype.h"
#include "options/quantifiers_options.h"
#include "options/datatypes_options.h"
#include "smt/smt_statistics_registry.h"
#include "theory/quantifiers/first_order_model.h"
#include "theory/quantifiers/term_database.h"
#include "theory/theory_engine.h"
#include "prop/prop_engine.h"
#include "theory/bv/theory_bv_rewriter.h"

using namespace CVC4::kind;
using namespace std;

namespace CVC4 {
namespace theory {
namespace quantifiers {


CegConjecture::CegConjecture( QuantifiersEngine * qe, context::Context* c )
    : d_qe( qe ) {
  d_refine_count = 0;
  d_ceg_si = new CegConjectureSingleInv( qe, this );
  d_ceg_pbe = new CegConjecturePbe( qe, this );
}

CegConjecture::~CegConjecture() {
  delete d_ceg_si;
  delete d_ceg_pbe;
}

Node CegConjecture::convertToEmbedding( Node n, std::map< Node, Node >& synth_fun_vars, std::map< Node, Node >& visited ){
  std::map< Node, Node >::iterator it = visited.find( n );
  if( it==visited.end() ){
    Node ret = n;
    
    std::vector< Node > children;
    bool childChanged = false;
    bool madeOp = false;
    Kind ret_k = n.getKind();
    Node op;
    if( n.getNumChildren()>0 ){
      if( n.getKind()==kind::APPLY_UF ){
        op = n.getOperator();
      }
    }else{
      op = n;
    }
    // is it a synth function?
    std::map< Node, Node >::iterator its = synth_fun_vars.find( op );
    if( its!=synth_fun_vars.end() ){
      Assert( its->second.getType().isDatatype() );
      // make into evaluation function
      const Datatype& dt = ((DatatypeType)its->second.getType().toType()).getDatatype();
      Assert( dt.isSygus() );
      children.push_back( Node::fromExpr( dt.getSygusEvaluationFunc() ) );
      children.push_back( its->second );
      madeOp = true;
      childChanged = true;
      ret_k = kind::APPLY_UF;
    }
    if( n.getNumChildren()>0 || childChanged ){
      if( !madeOp ){
        if( n.getMetaKind() == kind::metakind::PARAMETERIZED ){
          children.push_back( n.getOperator() );
        }
      }
      for( unsigned i=0; i<n.getNumChildren(); i++ ){
        Node nc = convertToEmbedding( n[i], synth_fun_vars, visited ); 
        childChanged = childChanged || nc!=n[i];
        children.push_back( nc );
      }
      if( childChanged ){
        ret = NodeManager::currentNM()->mkNode( ret_k, children );
      }
    }
    visited[n] = ret;
    return ret;
  }else{
    return it->second;
  }
}

void CegConjecture::collectConstants( Node n, std::map< TypeNode, std::vector< Node > >& consts, std::map< Node, bool >& visited ) {
  if( visited.find( n )==visited.end() ){
    visited[n] = true;
    if( n.isConst() ){
      TypeNode tn = n.getType();
      Node nc = n;
      if( tn.isReal() ){
        nc = NodeManager::currentNM()->mkConst( n.getConst<Rational>().abs() );
      }
      if( std::find( consts[tn].begin(), consts[tn].end(), nc )==consts[tn].end() ){
        Trace("cegqi-debug") << "...consider const : " << nc << std::endl;
        consts[tn].push_back( nc );
      }
    }
    
    for( unsigned i=0; i<n.getNumChildren(); i++ ){
      collectConstants( n[i], consts, visited );
    }
  }
}

void CegConjecture::assign( Node q ) {
  Assert( d_quant.isNull() );
  Assert( q.getKind()==FORALL );
  Trace("cegqi") << "CegConjecture : assign : " << q << std::endl;
  d_assert_quant = q;
  std::map< TypeNode, std::vector< Node > > extra_cons;
  
  Trace("cegqi") << "CegConjecture : collect constants..." << std::endl;
  if( options::sygusAddConstGrammar() ){
    std::map< Node, bool > cvisited;
    collectConstants( q[1], extra_cons, cvisited );
  } 
  
  Trace("cegqi") << "CegConjecture : convert to deep embedding..." << std::endl;
  //convert to deep embedding
  std::vector< Node > qchildren;
  std::map< Node, Node > visited;
  std::map< Node, Node > synth_fun_vars;
  std::vector< Node > ebvl;
  for( unsigned i=0; i<q[0].getNumChildren(); i++ ){
    Node v = q[0][i];
    Node sf = v.getAttribute(SygusSynthFunAttribute());
    Assert( !sf.isNull() );
    Node sfvl = sf.getAttribute(SygusSynthFunVarListAttribute());
    // sfvl may be null for constant synthesis functions
    Trace("cegqi-debug") << "...sygus var list associated with " << sf << " is " << sfvl << std::endl;
    TypeNode tn;
    if( v.getType().isDatatype() && ((DatatypeType)v.getType().toType()).getDatatype().isSygus() ){
      tn = v.getType();
    }else{
      // make the default grammar
      std::stringstream ss;
      ss << sf;
      tn = d_qe->getTermDatabaseSygus()->mkSygusDefaultType( v.getType(), sfvl, ss.str(), extra_cons );
    }
    d_qe->getTermDatabaseSygus()->registerSygusType( tn );
    // ev is the first-order variable corresponding to this synth fun
    std::stringstream ss;
    ss << "f" << sf;
    Node ev = NodeManager::currentNM()->mkBoundVar( ss.str(), tn ); 
    ebvl.push_back( ev );
    synth_fun_vars[sf] = ev;
    Trace("cegqi") << "...embedding synth fun : " << sf << " -> " << ev << std::endl;
  }
  qchildren.push_back( NodeManager::currentNM()->mkNode( kind::BOUND_VAR_LIST, ebvl ) );
  qchildren.push_back( convertToEmbedding( q[1], synth_fun_vars, visited ) );
  if( q.getNumChildren()==3 ){
    qchildren.push_back( q[2] );
  }
  q = NodeManager::currentNM()->mkNode( kind::FORALL, qchildren );
  Trace("cegqi") << "CegConjecture : converted to embedding : " << q << std::endl;

  //register with single invocation if applicable
  if( d_qe->getTermDatabase()->isQAttrSygus( d_assert_quant ) && options::cegqiSingleInvMode()!=CEGQI_SI_MODE_NONE ){
    d_ceg_si->initialize( q );
    if( q!=d_ceg_si->d_quant ){
      //Node red_lem = NodeManager::currentNM()->mkNode( OR, q.negate(), d_cegqi_si->d_quant );
      //may have rewritten quantified formula (for invariant synthesis)
      q = d_ceg_si->d_quant;
      Assert( q.getKind()==kind::FORALL );
    }
  }

  d_quant = q;
  Assert( d_candidates.empty() );
  std::vector< Node > vars;
  for( unsigned i=0; i<q[0].getNumChildren(); i++ ){
    vars.push_back( q[0][i] );
    Node e = NodeManager::currentNM()->mkSkolem( "e", q[0][i].getType() );
    d_candidates.push_back( e );
  }
  Trace("cegqi") << "Base quantified formula is : " << q << std::endl;
  //construct base instantiation
  d_base_inst = Rewriter::rewrite( d_qe->getInstantiation( q, vars, d_candidates ) );
  
  // register this term with sygus database
  std::vector< Node > guarded_lemmas;
  if( !isSingleInvocation() ){
    if( options::sygusPbe() ){
      d_ceg_pbe->initialize( d_base_inst, d_candidates, guarded_lemmas );
    }
    for( unsigned i=0; i<d_candidates.size(); i++ ){
      Node e = d_candidates[i];
      if( options::sygusPbe() ){
        std::vector< std::vector< Node > > exs;
        std::vector< Node > exos;
        std::vector< Node > exts;
        // use the PBE examples, regardless of the search algorith, since these help search space pruning
        if( d_ceg_pbe->getPbeExamples( e, exs, exos, exts ) ){
          d_qe->getTermDatabaseSygus()->registerPbeExamples( e, exs, exos, exts );
        }
      }else{
        d_qe->getTermDatabaseSygus()->registerMeasuredTerm( e, e );
      }
    }
  }
  
  Trace("cegqi") << "Base instantiation is :      " << d_base_inst << std::endl;
  if( d_qe->getTermDatabase()->isQAttrSygus( d_assert_quant ) ){
    CegInstantiation::collectDisjuncts( d_base_inst, d_base_disj );
    Trace("cegqi") << "Conjecture has " << d_base_disj.size() << " disjuncts." << std::endl;
    //store the inner variables for each disjunct
    for( unsigned j=0; j<d_base_disj.size(); j++ ){
      Trace("cegqi") << "  " << j << " : " << d_base_disj[j] << std::endl;
      d_inner_vars_disj.push_back( std::vector< Node >() );
      //if the disjunct is an existential, store it
      if( d_base_disj[j].getKind()==NOT && d_base_disj[j][0].getKind()==FORALL ){
        for( unsigned k=0; k<d_base_disj[j][0][0].getNumChildren(); k++ ){
          d_inner_vars.push_back( d_base_disj[j][0][0][k] );
          d_inner_vars_disj[j].push_back( d_base_disj[j][0][0][k] );
        }
      }
    }
    d_syntax_guided = true;
  }else if( d_qe->getTermDatabase()->isQAttrSynthesis( d_assert_quant ) ){
    d_syntax_guided = false;
  }else{
    Assert( false );
  }
  
  // initialize the guard
  if( !d_syntax_guided ){
    if( d_nsg_guard.isNull() ){
      d_nsg_guard = Rewriter::rewrite( NodeManager::currentNM()->mkSkolem( "G", NodeManager::currentNM()->booleanType() ) );
      d_nsg_guard = d_qe->getValuation().ensureLiteral( d_nsg_guard );
      AlwaysAssert( !d_nsg_guard.isNull() );
      d_qe->getOutputChannel().requirePhase( d_nsg_guard, true );
      // negated base as a guarded lemma
      guarded_lemmas.push_back( d_base_inst.negate() );
    }
  }else if( d_ceg_si->d_si_guard.isNull() ){
    std::vector< Node > lems;
    d_ceg_si->getInitialSingleInvLemma( lems );
    for( unsigned i=0; i<lems.size(); i++ ){
      Trace("cegqi-lemma") << "Cegqi::Lemma : single invocation " << i << " : " << lems[i] << std::endl;
      d_qe->getOutputChannel().lemma( lems[i] );
      if( Trace.isOn("cegqi-debug") ){
        Node rlem = Rewriter::rewrite( lems[i] );
        Trace("cegqi-debug") << "...rewritten : " << rlem << std::endl;
      }
    }
  }
  Assert( !getGuard().isNull() );
  Node gneg = getGuard().negate();
  for( unsigned i=0; i<guarded_lemmas.size(); i++ ){
    Node lem = NodeManager::currentNM()->mkNode( OR, gneg, guarded_lemmas[i] );
    Trace("cegqi-lemma") << "Cegqi::Lemma : initial (guarded) lemma : " << lem << std::endl;
    d_qe->getOutputChannel().lemma( lem );
  }
  
  Trace("cegqi") << "...finished, single invocation = " << isSingleInvocation() << std::endl;
}

Node CegConjecture::getGuard() {
  return !d_syntax_guided ? d_nsg_guard : d_ceg_si->d_si_guard;
}

bool CegConjecture::isSingleInvocation() const {
  return d_ceg_si->isSingleInvocation();
}

bool CegConjecture::isFullySingleInvocation() {
  return d_ceg_si->isFullySingleInvocation();
}

bool CegConjecture::needsCheck( std::vector< Node >& lem ) {
  if( isSingleInvocation() && !d_ceg_si->needsCheck() ){
    return false;
  }else{
    bool value;
    if( !isSingleInvocation() || isFullySingleInvocation() ){
      Assert( !getGuard().isNull() );
      // non or fully single invocation : look at guard only
      if( d_qe->getValuation().hasSatValue( getGuard(), value ) ) {
        if( !value ){
          Trace("cegqi-engine-debug") << "Conjecture is infeasible." << std::endl;
          return false;
        }
      }else{
        Assert( false );
      }
    }else{
      // not fully single invocation : infeasible if overall specification is infeasible
      Assert( !d_ceg_si->d_full_guard.isNull() );
      if( d_qe->getValuation().hasSatValue( d_ceg_si->d_full_guard, value ) ) {
        if( !value ){
          Trace("cegqi-nsi") << "NSI : found full specification is infeasible." << std::endl;
          return false;
        }else{
          Assert( !d_ceg_si->d_si_guard.isNull() );
          if( d_qe->getValuation().hasSatValue( d_ceg_si->d_si_guard, value ) ) {
            if( !value ){
              if( !d_ceg_si->d_single_inv_exp.isNull() ){
                //this should happen infrequently : only if cegqi determines infeasibility of a false candidate before E-matching does
                Trace("cegqi-nsi") << "NSI : current single invocation lemma was infeasible, block assignment upon which conjecture was based." << std::endl;
                Node l = NodeManager::currentNM()->mkNode( OR, d_ceg_si->d_full_guard.negate(), d_ceg_si->d_single_inv_exp );
                lem.push_back( l );
                d_ceg_si->initializeNextSiConjecture();
              }
              return false;
            }
          }else{
            Assert( false );
          }
        }
      }else{
        Assert( false );
      }
    }
    return true;
  }
}


void CegConjecture::doCegConjectureSingleInvCheck(std::vector< Node >& lems) {
  if( d_ceg_si!=NULL ){
    d_ceg_si->check(lems);
  }
}

bool CegConjecture::needsRefinement() { 
  return !d_ce_sk.empty();
}

void CegConjecture::getCandidateList( std::vector< Node >& clist, bool forceOrig ) {
  if( d_ceg_pbe->isPbe() && !forceOrig ){
    //Assert( isGround() );
    d_ceg_pbe->getCandidateList( d_candidates, clist );
  }else{
    clist.insert( clist.end(), d_candidates.begin(), d_candidates.end() );
  }
}

bool CegConjecture::constructCandidates( std::vector< Node >& clist, std::vector< Node >& model_values, std::vector< Node >& candidate_values, 
                                         std::vector< Node >& lems ) {
  Assert( clist.size()==model_values.size() );
  if( d_ceg_pbe->isPbe() ){
    //Assert( isGround() );
    return d_ceg_pbe->constructCandidates( clist, model_values, d_candidates, candidate_values, lems );
  }else{
    Assert( model_values.size()==d_candidates.size() );
    candidate_values.insert( candidate_values.end(), model_values.begin(), model_values.end() );
  }
  return true;
}

void CegConjecture::doCegConjectureCheck(std::vector< Node >& lems, std::vector< Node >& model_values) {
  std::vector< Node > clist;
  getCandidateList( clist );
  std::vector< Node > c_model_values;
  Trace("cegqi-check") << "CegConjuncture : check, build candidates..." << std::endl;
  bool constructed_cand = constructCandidates( clist, model_values, c_model_values, lems );

  //must get a counterexample to the value of the current candidate
  Node inst;
  if( constructed_cand ){
    if( Trace.isOn("cegqi-check")  ){
      Trace("cegqi-check") << "CegConjuncture : check candidate : " << std::endl;
      for( unsigned i=0; i<c_model_values.size(); i++ ){
        Trace("cegqi-check") << "  " << i << " : " << d_candidates[i] << " -> " << c_model_values[i] << std::endl;
      }
    }
    Assert( c_model_values.size()==d_candidates.size() );
    inst = d_base_inst.substitute( d_candidates.begin(), d_candidates.end(), c_model_values.begin(), c_model_values.end() );
  }else{
    inst = d_base_inst;
  }
  
  //check whether we will run CEGIS on inner skolem variables
  bool sk_refine = ( !isGround() || d_refine_count==0 ) && ( !d_ceg_pbe->isPbe() || constructed_cand );
  if( sk_refine ){
    Assert( d_ce_sk.empty() );
    d_ce_sk.push_back( std::vector< Node >() );
  }else{
    if( !constructed_cand ){
      return;
    }
  }
  
  std::vector< Node > ic;
  ic.push_back( d_assert_quant.negate() );
  std::vector< Node > d;
  CegInstantiation::collectDisjuncts( inst, d );
  Assert( d.size()==d_base_disj.size() );
  //immediately skolemize inner existentials
  for( unsigned i=0; i<d.size(); i++ ){
    Node dr = Rewriter::rewrite( d[i] );
    if( dr.getKind()==NOT && dr[0].getKind()==FORALL ){
      if( constructed_cand ){
        ic.push_back( d_qe->getTermDatabase()->getSkolemizedBody( dr[0] ).negate() );
      }
      if( sk_refine ){
        Assert( !isGround() );
        d_ce_sk.back().push_back( dr[0] );
      }
    }else{
      if( constructed_cand ){
        ic.push_back( dr );
        if( !d_inner_vars_disj[i].empty() ){
          Trace("cegqi-debug") << "*** quantified disjunct : " << d[i] << " simplifies to " << dr << std::endl;
        }
      }
      if( sk_refine ){
        d_ce_sk.back().push_back( Node::null() );
      }
    }
  }
  if( constructed_cand ){
    Node lem = NodeManager::currentNM()->mkNode( OR, ic );
    lem = Rewriter::rewrite( lem );
    //eagerly unfold applications of evaluation function
    if( options::sygusDirectEval() ){
      Trace("cegqi-debug") << "pre-unfold counterexample : " << lem << std::endl;
      std::map< Node, Node > visited_n;
      lem = d_qe->getTermDatabaseSygus()->getEagerUnfold( lem, visited_n );
    }
    lems.push_back( lem );
    recordInstantiation( c_model_values );
  }
}
        
void CegConjecture::doCegConjectureRefine( std::vector< Node >& lems ){
  Assert( lems.empty() );
  Assert( d_ce_sk.size()==1 );

  //first, make skolem substitution
  Trace("cegqi-refine") << "doCegConjectureRefine : construct skolem substitution..." << std::endl;
  std::vector< Node > sk_vars;
  std::vector< Node > sk_subs;
  //collect the substitution over all disjuncts
  for( unsigned k=0; k<d_ce_sk[0].size(); k++ ){
    Node ce_q = d_ce_sk[0][k];
    if( !ce_q.isNull() ){
      Assert( !d_inner_vars_disj[k].empty() );
      Assert( d_inner_vars_disj[k].size()==d_qe->getTermDatabase()->d_skolem_constants[ce_q].size() );
      std::vector< Node > model_values;
      getModelValues( d_qe->getTermDatabase()->d_skolem_constants[ce_q], model_values );
      sk_vars.insert( sk_vars.end(), d_inner_vars_disj[k].begin(), d_inner_vars_disj[k].end() );
      sk_subs.insert( sk_subs.end(), model_values.begin(), model_values.end() );
    }else{
      if( !d_inner_vars_disj[k].empty() ){
        //denegrate case : quantified disjunct was trivially true and does not need to be refined
        //add trivial substitution (in case we need substitution for previous cex's)
        for( unsigned i=0; i<d_inner_vars_disj[k].size(); i++ ){
          sk_vars.push_back( d_inner_vars_disj[k][i] );
          sk_subs.push_back( getModelValue( d_inner_vars_disj[k][i] ) ); // will return dummy value
        }
      }
    }
  }
  
  std::map< Node, Node > csol_active;
  std::map< Node, std::vector< Node > > csol_ccond_nodes;
  std::map< Node, std::map< Node, bool > > csol_cpol;    
  
  //for conditional evaluation
  std::map< Node, Node > psubs_visited;
  std::map< Node, Node > psubs;
  std::vector< Node > lem_c;
  Assert( d_ce_sk[0].size()==d_base_disj.size() );
  std::vector< Node > inst_cond_c;
  Trace("cegqi-refine") << "doCegConjectureRefine : Construct refinement lemma..." << std::endl;
  for( unsigned k=0; k<d_ce_sk[0].size(); k++ ){
    Node ce_q = d_ce_sk[0][k];
    Trace("cegqi-refine-debug") << "  For counterexample point, disjunct " << k << " : " << ce_q << " " << d_base_disj[k] << std::endl;
    Node c_disj;
    if( !ce_q.isNull() ){
      Assert( d_base_disj[k].getKind()==kind::NOT && d_base_disj[k][0].getKind()==kind::FORALL );
      c_disj = d_base_disj[k][0][1];
    }else{
      if( d_inner_vars_disj[k].empty() ){
        c_disj = d_base_disj[k].negate();
      }else{
        //denegrate case : quantified disjunct was trivially true and does not need to be refined
        Trace("cegqi-refine-debug") << "*** skip " << d_base_disj[k] << std::endl;
      }
    }
    if( !c_disj.isNull() ){
      //compute the body, inst_cond
      //standard CEGIS refinement : plug in values, assert that d_candidates must satisfy entire specification
      lem_c.push_back( c_disj );
    }
  }
  Assert( sk_vars.size()==sk_subs.size() );
  //add conditional correctness assumptions
  std::vector< Node > psubs_cond_ant;
  std::vector< Node > psubs_cond_conc;
  std::map< Node, std::vector< Node > > psubs_apply;
  std::vector< Node > paux_vars;
  Assert( psubs.empty() );
  
  Node base_lem = lem_c.size()==1 ? lem_c[0] : NodeManager::currentNM()->mkNode( AND, lem_c );
  
  Trace("cegqi-refine") << "doCegConjectureRefine : construct and finalize lemmas..." << std::endl;
  
  Node lem = base_lem;
  
  base_lem = base_lem.substitute( sk_vars.begin(), sk_vars.end(), sk_subs.begin(), sk_subs.end() );
  base_lem = Rewriter::rewrite( base_lem );
  d_refinement_lemmas_base.push_back( base_lem );
  
  lem = NodeManager::currentNM()->mkNode( OR, getGuard().negate(), lem );
  
  lem = lem.substitute( sk_vars.begin(), sk_vars.end(), sk_subs.begin(), sk_subs.end() );
  lem = Rewriter::rewrite( lem );
  d_refinement_lemmas.push_back( lem );
  lems.push_back( lem );

  d_ce_sk.clear();
}

void CegConjecture::preregisterConjecture( Node q ) {
  d_ceg_si->preregisterConjecture( q );
}

void CegConjecture::getModelValues( std::vector< Node >& n, std::vector< Node >& v ) {
  Trace("cegqi-engine") << "  * Value is : ";
  for( unsigned i=0; i<n.size(); i++ ){
    Node nv = getModelValue( n[i] );
    v.push_back( nv );
    if( Trace.isOn("cegqi-engine") ){
      TypeNode tn = nv.getType();
      Trace("cegqi-engine") << n[i] << " -> ";
      std::stringstream ss;
      std::vector< Node > lvs;
      TermDbSygus::printSygusTerm( ss, nv, lvs );
      Trace("cegqi-engine") << ss.str() << " ";
    }
    Assert( !nv.isNull() );
  }
  Trace("cegqi-engine") << std::endl;
}

Node CegConjecture::getModelValue( Node n ) {
  Trace("cegqi-mv") << "getModelValue for : " << n << std::endl;
  return d_qe->getModel()->getValue( n );
}

void CegConjecture::debugPrint( const char * c ) {
  Trace(c) << "Synthesis conjecture : " << d_quant << std::endl;
  Trace(c) << "  * Candidate program/output symbol : ";
  for( unsigned i=0; i<d_candidates.size(); i++ ){
    Trace(c) << d_candidates[i] << " ";
  }
  Trace(c) << std::endl;
  Trace(c) << "  * Candidate ce skolems : ";
  for( unsigned i=0; i<d_ce_sk.size(); i++ ){
    Trace(c) << d_ce_sk[i] << " ";
  }
}

CegInstantiation::CegInstantiation( QuantifiersEngine * qe, context::Context* c ) : QuantifiersModule( qe ){
  d_conj = new CegConjecture( qe, qe->getSatContext() );
  d_last_inst_si = false;
}

CegInstantiation::~CegInstantiation(){ 
  delete d_conj;
}

bool CegInstantiation::needsCheck( Theory::Effort e ) {
  return e>=Theory::EFFORT_LAST_CALL;
}

unsigned CegInstantiation::needsModel( Theory::Effort e ) {
  return d_conj->getCegConjectureSingleInv()->isSingleInvocation()
      ? QuantifiersEngine::QEFFORT_STANDARD : QuantifiersEngine::QEFFORT_MODEL;
}

void CegInstantiation::check( Theory::Effort e, unsigned quant_e ) {
  unsigned echeck = d_conj->getCegConjectureSingleInv()->isSingleInvocation() ?
      QuantifiersEngine::QEFFORT_STANDARD : QuantifiersEngine::QEFFORT_MODEL;
  if( quant_e==echeck ){
    Trace("cegqi-engine") << "---Counterexample Guided Instantiation Engine---" << std::endl;
    Trace("cegqi-engine-debug") << std::endl;
    bool active = false;
    bool value;
    if( d_quantEngine->getValuation().hasSatValue( d_conj->d_assert_quant, value ) ) {
      active = value;
    }else{
      Trace("cegqi-engine-debug") << "...no value for quantified formula." << std::endl;
    }
    Trace("cegqi-engine-debug") << "Current conjecture status : active : " << active << std::endl;
    std::vector< Node > lem;
    if( active && d_conj->needsCheck( lem ) ){
      checkCegConjecture( d_conj );
    }else{
      Trace("cegqi-engine-debug") << "...does not need check." << std::endl;
      for( unsigned i=0; i<lem.size(); i++ ){
        Trace("cegqi-lemma") << "Cegqi::Lemma : check lemma : " << lem[i] << std::endl;
        d_quantEngine->addLemma( lem[i] );
      }
    }
    Trace("cegqi-engine") << "Finished Counterexample Guided Instantiation engine." << std::endl;
  }
}

void CegInstantiation::preRegisterQuantifier( Node q ) {
/*
  if( options::sygusDirectEval() ){
    if( q.getNumChildren()==3 && q[2].getKind()==INST_PATTERN_LIST && q[2][0].getKind()==INST_PATTERN ){  
      //check whether it is an evaluation axiom
      Node pat = q[2][0][0];
      if( pat.getKind()==APPLY_UF ){
        TypeNode tn = pat[0].getType();
        if( tn.isDatatype() ){
          const Datatype& dt = ((DatatypeType)(tn).toType()).getDatatype();
          if( dt.isSygus() ){
            //do unfolding if it induces Boolean structure, 
            //do direct evaluation if it does not induce Boolean structure,
            //  the reasoning is unfolding over these terms does not lead to helpful conflict analysis, and introduces many shared terms
            bool directEval = true;
            TypeNode ptn = pat.getType();
            if( ptn.isBoolean() ){
              directEval = false;
            }else{
              unsigned cindex = Datatype::indexOf(pat[0].getOperator().toExpr() );
              Node base = d_quantEngine->getTermDatabaseSygus()->getGenericBase( tn, dt, cindex );
              Trace("cegqi-debug") << "Generic base term for " << pat[0] << " is " << base << std::endl;
              if( base.getKind()==ITE ){
                directEval = false;
              }
            }
            if( directEval ){
              //take ownership of this quantified formula (will use direct evaluation instead of unfolding instantiation)
              d_quantEngine->setOwner( q, this );
              d_eval_axioms[q] = true;
            }
          }
        }
      }
    }
  } 
  */ 
}

void CegInstantiation::registerQuantifier( Node q ) {
  if( d_quantEngine->getOwner( q )==this ){ // && d_eval_axioms.find( q )==d_eval_axioms.end() ){
    if( !d_conj->isAssigned() ){
      Trace("cegqi") << "Register conjecture : " << q << std::endl;
      d_conj->assign( q );
    }else{
      Assert( d_conj->d_quant==q );
    }
  }else{
    Trace("cegqi-debug") << "Register quantifier : " << q << std::endl;
  }
}

void CegInstantiation::assertNode( Node n ) {
}

Node CegInstantiation::getNextDecisionRequest( unsigned& priority ) {
  if( d_conj->isAssigned() ){
    std::vector< Node > req_dec;
    const CegConjectureSingleInv* ceg_si = d_conj->getCegConjectureSingleInv();
    if( ! ceg_si->d_full_guard.isNull() ){
      req_dec.push_back( ceg_si->d_full_guard );
    }
    //must decide ns guard before s guard
    if( !ceg_si->d_ns_guard.isNull() ){
      req_dec.push_back( ceg_si->d_ns_guard );
    }
    req_dec.push_back( d_conj->getGuard() );
    for( unsigned i=0; i<req_dec.size(); i++ ){
      bool value;
      if( !d_quantEngine->getValuation().hasSatValue( req_dec[i], value ) ) {
        Trace("cegqi-debug") << "CEGQI : Decide next on : " << req_dec[i] << "..." << std::endl;
        priority = 0;
        return req_dec[i];
      }else{
        Trace("cegqi-debug2") << "CEGQI : " << req_dec[i] << " already has value " << value << std::endl;
      }
    }
  }
  return Node::null();
}

void CegInstantiation::checkCegConjecture( CegConjecture * conj ) {
  Node q = conj->d_quant;
  Node aq = conj->d_assert_quant;
  if( Trace.isOn("cegqi-engine-debug") ){
    conj->debugPrint("cegqi-engine-debug");
    Trace("cegqi-engine-debug") << std::endl;
  }

  if( !conj->needsRefinement() ){
    Trace("cegqi-engine-debug") << "Do conjecture check..." << std::endl;
    if( conj->d_syntax_guided ){
      std::vector< Node > clems;
      conj->doCegConjectureSingleInvCheck( clems );
      if( !clems.empty() ){
        d_last_inst_si = true;
        for( unsigned j=0; j<clems.size(); j++ ){
          Trace("cegqi-lemma") << "Cegqi::Lemma : single invocation instantiation : " << clems[j] << std::endl;
          d_quantEngine->addLemma( clems[j] );
        }
        d_statistics.d_cegqi_si_lemmas += clems.size();
        Trace("cegqi-engine") << "  ...try single invocation." << std::endl;
        return;
      }
      //ignore return value here
      std::vector< Node > clist;
      conj->getCandidateList( clist );
      std::vector< Node > model_values;
      conj->getModelValues( clist, model_values );
      if( options::sygusDirectEval() ){
        bool addedEvalLemmas = false;
        if( options::sygusCRefEval() ){
          Trace("cegqi-engine") << "  *** Do conjecture refinement evaluation..." << std::endl;
          // see if any refinement lemma is refuted by evaluation
          std::vector< Node > cre_lems;
          getCRefEvaluationLemmas( conj, clist, model_values, cre_lems );
          if( !cre_lems.empty() ){
            for( unsigned j=0; j<cre_lems.size(); j++ ){
              Node lem = cre_lems[j];
              if( d_quantEngine->addLemma( lem ) ){
                Trace("cegqi-lemma") << "Cegqi::Lemma : cref evaluation : " << lem << std::endl;
                addedEvalLemmas = true;
              }
            }
            if( addedEvalLemmas ){
              //return;
            }
          }
        }
        Trace("cegqi-engine") << "  *** Do direct evaluation..." << std::endl;
        std::vector< Node > eager_terms; 
        std::vector< Node > eager_vals; 
        std::vector< Node > eager_exps;
        for( unsigned j=0; j<clist.size(); j++ ){
          Trace("cegqi-debug") << "  register " << clist[j] << " -> " << model_values[j] << std::endl;
          d_quantEngine->getTermDatabaseSygus()->registerModelValue( clist[j], model_values[j], eager_terms, eager_vals, eager_exps );
        }
        Trace("cegqi-debug") << "...produced " << eager_terms.size()  << " eager evaluation lemmas." << std::endl;
        if( !eager_terms.empty() ){
          for( unsigned j=0; j<eager_terms.size(); j++ ){
            Node lem = NodeManager::currentNM()->mkNode( kind::OR, eager_exps[j].negate(), eager_terms[j].eqNode( eager_vals[j] ) );
            if( d_quantEngine->getTheoryEngine()->isTheoryEnabled(THEORY_BV) ){
              //FIXME: hack to incorporate hacks from BV for division by zero
              lem = bv::TheoryBVRewriter::eliminateBVSDiv( lem );
            }
            if( d_quantEngine->addLemma( lem ) ){
              Trace("cegqi-lemma") << "Cegqi::Lemma : evaluation : " << lem << std::endl;
              addedEvalLemmas = true;
            }
          }
        }
        if( addedEvalLemmas ){
          return;
        }
      }
      
      Trace("cegqi-engine") << "  *** Check candidate phase..." << std::endl;
      std::vector< Node > cclems;
      conj->doCegConjectureCheck( cclems, model_values );
      bool addedLemma = false;
      for( unsigned i=0; i<cclems.size(); i++ ){
        Node lem = cclems[i];
        d_last_inst_si = false;
        Trace("cegqi-lemma") << "Cegqi::Lemma : counterexample : " << lem << std::endl;
        if( d_quantEngine->addLemma( lem ) ){
          ++(d_statistics.d_cegqi_lemmas_ce);
          addedLemma = true;
        }else{
          //this may happen if we eagerly unfold, simplify to true
          if( !options::sygusDirectEval() ){
            Trace("cegqi-warn") << "  ...FAILED to add candidate!" << std::endl;
          }else{
            Trace("cegqi-engine-debug") << "  ...FAILED to add candidate!" << std::endl;
          }
        }
      }
      if( addedLemma ){
        Trace("cegqi-engine") << "  ...check for counterexample." << std::endl;
      }else{
        if( conj->needsRefinement() ){
          //immediately go to refine candidate
          checkCegConjecture( conj );
          return;
        }
      } 
    }else{
      Assert( aq==q );
      std::vector< Node > model_terms;
      std::vector< Node > clist;
      conj->getCandidateList( clist, true );
      Assert( clist.size()==q[0].getNumChildren() );
      conj->getModelValues( clist, model_terms );
      if( d_quantEngine->addInstantiation( q, model_terms ) ){
        conj->recordInstantiation( model_terms );
      }else{
        Assert( false );
      }
    }
  }else{
    Trace("cegqi-engine") << "  *** Refine candidate phase..." << std::endl;
    std::vector< Node > rlems;
    conj->doCegConjectureRefine( rlems );
    bool addedLemma = false;
    for( unsigned i=0; i<rlems.size(); i++ ){
      Node lem = rlems[i];
      Trace("cegqi-lemma") << "Cegqi::Lemma : candidate refinement : " << lem << std::endl;
      bool res = d_quantEngine->addLemma( lem );
      if( res ){
        ++(d_statistics.d_cegqi_lemmas_refine);
        conj->d_refine_count++;
        addedLemma = true;
      }else{
        Trace("cegqi-warn") << "  ...FAILED to add refinement!" << std::endl;
      }
    }
    if( addedLemma ){
      Trace("cegqi-engine") << "  ...refine candidate." << std::endl;
    }
  }
}

void CegInstantiation::getCRefEvaluationLemmas( CegConjecture * conj, std::vector< Node >& vs, std::vector< Node >& ms, std::vector< Node >& lems ) {
  Trace("sygus-cref-eval") << "Cref eval : conjecture has " << conj->getNumRefinementLemmas() << " refinement lemmas." << std::endl;
  if( conj->getNumRefinementLemmas()>0 ){
    Assert( vs.size()==ms.size() );

    Node neg_guard = conj->getGuard().negate();
    for( unsigned i=0; i<conj->getNumRefinementLemmas(); i++ ){
      Node lem;
      std::map< Node, Node > visited;
      std::map< Node, std::vector< Node > > exp;
      lem = conj->getRefinementBaseLemma( i );
      if( !lem.isNull() ){
        std::vector< Node > lem_conj;
        //break into conjunctions
        if( lem.getKind()==kind::AND ){
          for( unsigned i=0; i<lem.getNumChildren(); i++ ){
            lem_conj.push_back( lem[i] );
          }
        }else{
          lem_conj.push_back( lem );
        }
        EvalSygusInvarianceTest vsit;
        vsit.d_result = d_quantEngine->getTermDatabase()->d_false;
        for( unsigned j=0; j<lem_conj.size(); j++ ){
          Node lemc = lem_conj[j];
          Trace("sygus-cref-eval") << "Check refinement lemma conjunct " << lemc << " against current model." << std::endl;
          Trace("sygus-cref-eval2") << "Check refinement lemma conjunct " << lemc << " against current model." << std::endl;
          Node cre_lem;
          Node lemcs = lemc.substitute( vs.begin(), vs.end(), ms.begin(), ms.end() );
          Trace("sygus-cref-eval2") << "...under substitution it is : " << lemcs << std::endl;
          Node lemcsu = d_quantEngine->getTermDatabaseSygus()->evaluateWithUnfolding( lemcs, vsit.d_visited );
          Trace("sygus-cref-eval2") << "...after unfolding is : " << lemcsu << std::endl;
          if( lemcsu==d_quantEngine->getTermDatabase()->d_false ){
            std::vector< Node > msu;
            std::vector< Node > mexp;
            msu.insert( msu.end(), ms.begin(), ms.end() );
            for( unsigned k=0; k<vs.size(); k++ ){
              vsit.d_var = vs[k];
              vsit.d_update_nvn = msu[k];
              msu[k] = vs[k];
              // substitute for everything except this
              vsit.d_conj = lemc.substitute( vs.begin(), vs.end(), msu.begin(), msu.end() );
              // get minimal explanation for this
              Trace("sygus-cref-eval2-debug") << "  compute min explain of : " << vs[k] << " = " << vsit.d_update_nvn << std::endl;
              d_quantEngine->getTermDatabaseSygus()->getExplanationFor( vs[k], vsit.d_update_nvn, mexp, vsit );
              msu[k] = vsit.d_update_nvn;
            }
            if( !mexp.empty() ){
              Node en = mexp.size()==1 ? mexp[0] : NodeManager::currentNM()->mkNode( kind::AND, mexp );
              cre_lem = NodeManager::currentNM()->mkNode( kind::OR, en.negate(), neg_guard );
            }else{
              cre_lem = neg_guard;
            }
          }
          if( !cre_lem.isNull() ){
            if( std::find( lems.begin(), lems.end(), cre_lem )==lems.end() ){
              Trace("sygus-cref-eval") << "...produced lemma : " << cre_lem << std::endl;
              lems.push_back( cre_lem );
            }
          }
        }
      }
    }
  }
}

void CegInstantiation::printSynthSolution( std::ostream& out ) {
  if( d_conj->isAssigned() ){
    Trace("cegqi-debug") << "Printing synth solution..." << std::endl;
    //if( !(Trace.isOn("cegqi-stats")) ){
    //  out << "Solution:" << std::endl;
    //}
    for( unsigned i=0; i<d_conj->d_quant[0].getNumChildren(); i++ ){
      Node prog = d_conj->d_quant[0][i];
      Trace("cegqi-debug") << "  print solution for " << prog << std::endl;
      std::stringstream ss;
      ss << prog;
      std::string f(ss.str());
      f.erase(f.begin());
      TypeNode tn = prog.getType();
      Assert( tn.isDatatype() );
      const Datatype& dt = ((DatatypeType)(tn).toType()).getDatatype();
      Assert( dt.isSygus() );
      //get the solution
      Node sol;
      int status = -1;
      if( d_last_inst_si ){
        Assert( d_conj->getCegConjectureSingleInv() != NULL );
        sol = d_conj->getSingleInvocationSolution( i, tn, status );
        sol = sol.getKind()==LAMBDA ? sol[1] : sol;
      }else{
        Node cprog = d_conj->getCandidate( i );
        if( !d_conj->d_cinfo[cprog].d_inst.empty() ){
          sol = d_conj->d_cinfo[cprog].d_inst.back();
          // Check if this was based on a template, if so, we must do
          // Reconstruction
          if( d_conj->d_assert_quant!=d_conj->d_quant ){
            Node sygus_sol = sol;
            Trace("cegqi-inv") << "Sygus version of solution is : " << sol
                               << ", type : " << sol.getType() << std::endl;
            std::vector< Node > subs;
            Expr svl = dt.getSygusVarList();
            for( unsigned j=0; j<svl.getNumChildren(); j++ ){
              subs.push_back( Node::fromExpr( svl[j] ) );
            }
            //bool templIsPost = false;
            const CegConjectureSingleInv* ceg_si = d_conj->getCegConjectureSingleInv();
            Node templ = ceg_si->getTemplate( prog );
            /*
            if( options::sygusInvTemplMode() == SYGUS_INV_TEMPL_MODE_PRE ){
              const CegConjectureSingleInv* ceg_si = d_conj->getCegConjectureSingleInv();
              if(ceg_si->d_trans_pre.find( prog ) != ceg_si->d_trans_pre.end()){
                templ = ceg_si->getTransPre(prog);
                templIsPost = false;
              }
            }else if(options::sygusInvTemplMode() == SYGUS_INV_TEMPL_MODE_POST){
              const CegConjectureSingleInv* ceg_si = d_conj->getCegConjectureSingleInv();
              if(ceg_si->d_trans_post.find(prog) != ceg_si->d_trans_post.end()){
                templ = ceg_si->getTransPost(prog);
                templIsPost = true;
              }
            }
            */
            Trace("cegqi-inv") << "Template is " << templ << std::endl;
            if( !templ.isNull() ){
              TNode templa = ceg_si->getTemplateArg( prog );
              Assert( !templa.isNull() );
              std::vector<Node>& templ_vars = d_conj->getProgTempVars(prog);
              std::vector< Node > vars;
              vars.insert( vars.end(), templ_vars.begin(), templ_vars.end() );
              Node vl = Node::fromExpr( dt.getSygusVarList() );
              Assert(vars.size() == subs.size());
              if( Trace.isOn("cegqi-inv-debug") ){
                for( unsigned j=0; j<vars.size(); j++ ){
                  Trace("cegqi-inv-debug") << "  subs : " << vars[j] << " -> " << subs[j] << std::endl;
                }
              }
              //apply the substitution to the template
              templ = templ.substitute( vars.begin(), vars.end(), subs.begin(), subs.end() );
              TermDbSygus* sygusDb = getTermDatabase()->getTermDatabaseSygus();
              sol = sygusDb->sygusToBuiltin( sol, sol.getType() );
              Trace("cegqi-inv") << "Builtin version of solution is : "
                                 << sol << ", type : " << sol.getType()
                                 << std::endl;
              //sol = NodeManager::currentNM()->mkNode( templIsPost ? AND : OR, sol, templ );
              TNode tsol = sol;
              sol = templ.substitute( templa, tsol );
            }
            if( sol==sygus_sol ){
              sol = sygus_sol;
              status = 1;
            }else{
              Trace("cegqi-inv-debug") << "With template : " << sol << std::endl;
              sol = Rewriter::rewrite( sol );
              Trace("cegqi-inv-debug") << "Simplified : " << sol << std::endl;
              sol = d_conj->reconstructToSyntaxSingleInvocation(sol, tn, status);
              sol = sol.getKind()==LAMBDA ? sol[1] : sol;
            }
          }else{
            status = 1;
          }
        }else{
          Trace("cegqi-warn") << "WARNING : No recorded instantiations for syntax-guided solution!" << std::endl;
        }
      }
      if( !(Trace.isOn("cegqi-stats")) ){
        out << "(define-fun " << f << " ";
        if( dt.getSygusVarList().isNull() ){
          out << "() ";
        }else{
          out << dt.getSygusVarList() << " ";
        }
        out << dt.getSygusType() << " ";
        if( status==0 ){
          out << sol;
        }else{
          if( sol.isNull() ){
            out << "?";
          }else{
            std::vector< Node > lvs;
            TermDbSygus::printSygusTerm( out, sol, lvs );
          }
        }
        out << ")" << std::endl;
      }
    }
  }else{
    Assert( false );
  }
}

void CegInstantiation::collectDisjuncts( Node n, std::vector< Node >& d ) {
  if( n.getKind()==OR ){
    for( unsigned i=0; i<n.getNumChildren(); i++ ){
      collectDisjuncts( n[i], d );
    }
  }else{
    d.push_back( n );
  }
}

void CegInstantiation::preregisterAssertion( Node n ) {
  //check if it sygus conjecture
  if( TermDb::isSygusConjecture( n ) ){
    //this is a sygus conjecture
    Trace("cegqi") << "Preregister sygus conjecture : " << n << std::endl;
    d_conj->preregisterConjecture( n );
  }
}

CegInstantiation::Statistics::Statistics():
  d_cegqi_lemmas_ce("CegInstantiation::cegqi_lemmas_ce", 0),
  d_cegqi_lemmas_refine("CegInstantiation::cegqi_lemmas_refine", 0),
  d_cegqi_si_lemmas("CegInstantiation::cegqi_lemmas_si", 0)
{
  smtStatisticsRegistry()->registerStat(&d_cegqi_lemmas_ce);
  smtStatisticsRegistry()->registerStat(&d_cegqi_lemmas_refine);
  smtStatisticsRegistry()->registerStat(&d_cegqi_si_lemmas);
}

CegInstantiation::Statistics::~Statistics(){
  smtStatisticsRegistry()->unregisterStat(&d_cegqi_lemmas_ce);
  smtStatisticsRegistry()->unregisterStat(&d_cegqi_lemmas_refine);
  smtStatisticsRegistry()->unregisterStat(&d_cegqi_si_lemmas);
}

}/* namespace CVC4::theory::quantifiers */
}/* namespace CVC4::theory */
}/* namespace CVC4 */