/**CFile****************************************************************

  FileName    [sbd.c]

  SystemName  [ABC: Logic synthesis and verification system.]

  PackageName [SAT-based optimization using internal don't-cares.]

  Synopsis    []

  Author      [Alan Mishchenko]
  
  Affiliation [UC Berkeley]

  Date        [Ver. 1.0. Started - June 20, 2005.]

  Revision    [$Id: sbd.c,v 1.00 2005/06/20 00:00:00 alanmi Exp $]

***********************************************************************/

#include "sbdInt.h"

ABC_NAMESPACE_IMPL_START


////////////////////////////////////////////////////////////////////////
///                        DECLARATIONS                              ///
////////////////////////////////////////////////////////////////////////

////////////////////////////////////////////////////////////////////////
///                     FUNCTION DEFINITIONS                         ///
////////////////////////////////////////////////////////////////////////

/**Function*************************************************************

  Synopsis    [Constructs SAT solver for the window.]

  Description [The window for the pivot node (Pivot) is represented as
  a DFS ordered array of objects (vWinObjs) whose indexed in the array
  (which will be used as SAT variables) are given in array vObj2Var.
  The TFO nodes are listed as the last ones in vWinObjs. The root nodes
  are labeled with Abc_LitIsCompl() in vTfo and also given in vRoots.
  If fQbf is 1, returns the instance meant for QBF solving. It is using
  the last variable (LastVar) as the placeholder for the second copy
  of the pivot node.]
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
sat_solver * Sbd_ManSatSolver( sat_solver * pSat, Gia_Man_t * p, Vec_Int_t * vMirrors, 
                               int Pivot, Vec_Int_t * vWinObjs, Vec_Int_t * vObj2Var, 
                               Vec_Int_t * vTfo, Vec_Int_t * vRoots, int fQbf )
{
    Gia_Obj_t * pObj;
    int i, iLit = 1, iObj, Fan0, Fan1, Lit0m, Lit1m, Node, fCompl0, fCompl1, RetValue;
    int TfoStart = Vec_IntSize(vWinObjs) - Vec_IntSize(vTfo);
    int PivotVar = Vec_IntEntry(vObj2Var, Pivot);
    int LastVar = Vec_IntSize(vWinObjs) + Vec_IntSize(vTfo) + Vec_IntSize(vRoots);
    //Vec_IntPrint( vWinObjs );
    //Vec_IntPrint( vTfo );
    //Vec_IntPrint( vRoots );
    // create SAT solver
    if ( pSat == NULL )
        pSat = sat_solver_new();
    else
        sat_solver_restart( pSat );
    sat_solver_setnvars( pSat, Vec_IntSize(vWinObjs) + Vec_IntSize(vTfo) + Vec_IntSize(vRoots) + SBD_FVAR_MAX );
    // create constant 0 clause
    sat_solver_addclause( pSat, &iLit, &iLit + 1 );
    // add clauses for all nodes
    Vec_IntForEachEntryStart( vWinObjs, iObj, i, 1 )
    {
        pObj = Gia_ManObj( p, iObj );
        if ( Gia_ObjIsCi(pObj) )
            continue;
        assert( Gia_ObjIsAnd(pObj) );
        assert( Vec_IntEntry( vMirrors, iObj ) < 0 );
        Node = Vec_IntEntry( vObj2Var, iObj );
        Lit0m = Vec_IntEntry( vMirrors, Gia_ObjFaninId0(pObj, iObj) );
        Lit1m = Vec_IntEntry( vMirrors, Gia_ObjFaninId1(pObj, iObj) );
        Fan0 = Lit0m >= 0 ? Abc_Lit2Var(Lit0m) : Gia_ObjFaninId0(pObj, iObj);
        Fan1 = Lit1m >= 0 ? Abc_Lit2Var(Lit1m) : Gia_ObjFaninId1(pObj, iObj);
        Fan0 = Vec_IntEntry( vObj2Var, Fan0 );
        Fan1 = Vec_IntEntry( vObj2Var, Fan1 );
        fCompl0 = Gia_ObjFaninC0(pObj) ^ (Lit0m >= 0 && Abc_LitIsCompl(Lit0m));
        fCompl1 = Gia_ObjFaninC1(pObj) ^ (Lit1m >= 0 && Abc_LitIsCompl(Lit1m));
        if ( Gia_ObjIsXor(pObj) )
            sat_solver_add_xor( pSat, Node, Fan0, Fan1, fCompl0 ^ fCompl1 );
        else
            sat_solver_add_and( pSat, Node, Fan0, Fan1, fCompl0, fCompl1, 0 );
    }
    // add second clauses for the TFO
    Vec_IntForEachEntryStart( vWinObjs, iObj, i, TfoStart )
    {
        pObj = Gia_ManObj( p, iObj );
        assert( Gia_ObjIsAnd(pObj) );
        assert( Vec_IntEntry( vMirrors, iObj ) < 0 );
        Node = Vec_IntEntry( vObj2Var, iObj ) + Vec_IntSize(vTfo);
        Lit0m = Vec_IntEntry( vMirrors, Gia_ObjFaninId0(pObj, iObj) );
        Lit1m = Vec_IntEntry( vMirrors, Gia_ObjFaninId1(pObj, iObj) );
        Fan0 = Lit0m >= 0 ? Abc_Lit2Var(Lit0m) : Gia_ObjFaninId0(pObj, iObj);
        Fan1 = Lit1m >= 0 ? Abc_Lit2Var(Lit1m) : Gia_ObjFaninId1(pObj, iObj);
        Fan0 = Vec_IntEntry( vObj2Var, Fan0 );
        Fan1 = Vec_IntEntry( vObj2Var, Fan1 );
        Fan0 = Fan0 < TfoStart ? Fan0 : Fan0 + Vec_IntSize(vTfo);
        Fan1 = Fan1 < TfoStart ? Fan1 : Fan1 + Vec_IntSize(vTfo);
        if ( fQbf )
        {
            Fan0 = Fan0 == PivotVar ? LastVar : Fan0;
            Fan1 = Fan1 == PivotVar ? LastVar : Fan1;
        }
        fCompl0 = Gia_ObjFaninC0(pObj) ^ (!fQbf && Fan0 == PivotVar) ^ (Lit0m >= 0 && Abc_LitIsCompl(Lit0m));
        fCompl1 = Gia_ObjFaninC1(pObj) ^ (!fQbf && Fan1 == PivotVar) ^ (Lit1m >= 0 && Abc_LitIsCompl(Lit1m));
        if ( Gia_ObjIsXor(pObj) )
            sat_solver_add_xor( pSat, Node, Fan0, Fan1, fCompl0 ^ fCompl1 );
        else
            sat_solver_add_and( pSat, Node, Fan0, Fan1, fCompl0, fCompl1, 0 );
    }
    if ( Vec_IntSize(vRoots) > 0 )
    {
        // create XOR clauses for the roots
        int nVars = Vec_IntSize(vWinObjs) + Vec_IntSize(vTfo);
        Vec_Int_t * vFaninVars = Vec_IntAlloc( Vec_IntSize(vRoots) );
        Vec_IntForEachEntry( vRoots, iObj, i )
        {
            assert( Vec_IntEntry( vMirrors, iObj ) < 0 );
            Node = Vec_IntEntry( vObj2Var, iObj );
            Vec_IntPush( vFaninVars, Abc_Var2Lit(nVars, 0) );
            sat_solver_add_xor( pSat, Node, Node + Vec_IntSize(vTfo), nVars++, 0 );
        }
        // make OR clause for the last nRoots variables
        RetValue = sat_solver_addclause( pSat, Vec_IntArray(vFaninVars), Vec_IntLimit(vFaninVars) );
        Vec_IntFree( vFaninVars );
        if ( RetValue == 0 )
        {
            sat_solver_delete( pSat );
            return NULL;
        }
        assert( sat_solver_nvars(pSat) == nVars + SBD_FVAR_MAX );
    }
    else if ( fQbf )
    {
        int n, pLits[2];
        for ( n = 0; n < 2; n++ )
        {
            pLits[0] = Abc_Var2Lit( PivotVar, n );
            pLits[1] = Abc_Var2Lit( LastVar, n );
            RetValue = sat_solver_addclause( pSat, pLits, pLits + 2 );
            assert( RetValue );
        }
    }
    // finalize
    RetValue = sat_solver_simplify( pSat );
    if ( RetValue == 0 )
    {
        sat_solver_delete( pSat );
        return NULL;    
    }
    return pSat;
}

/**Function*************************************************************

  Synopsis    [Solves one SAT problem.]

  Description [Computes node function for PivotVar with fanins in vDivSet
  using don't-care represented in the SAT solver. Uses array vValues to 
  return the values of the first Vec_IntSize(vValues) SAT variables in case
  the implementation of the node with the given fanins does not exist.]
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
word Sbd_ManSolve( sat_solver * pSat, int PivotVar, int FreeVar, Vec_Int_t * vDivSet, Vec_Int_t * vDivVars, Vec_Int_t * vDivValues, Vec_Int_t * vTemp )
{
    int nBTLimit = 0;
    word uCube, uTruth = 0;
    int status, i, iVar, nFinal, * pFinal, pLits[2], nIter = 0;
    assert( FreeVar < sat_solver_nvars(pSat) );
    assert( Vec_IntSize(vDivVars) == Vec_IntSize(vDivValues) );
    pLits[0] = Abc_Var2Lit( PivotVar, 0 ); // F = 1
    pLits[1] = Abc_Var2Lit( FreeVar, 0 );  // iNewLit
    while ( 1 ) 
    {
        // find onset minterm
        status = sat_solver_solve( pSat, pLits, pLits + 2, nBTLimit, 0, 0, 0 );
        if ( status == l_Undef )
            return SBD_SAT_UNDEC;
        if ( status == l_False )
            return uTruth;
        assert( status == l_True );
        // remember variable values
        Vec_IntForEachEntry( vDivVars, iVar, i )
            Vec_IntWriteEntry( vDivValues, i, 2*sat_solver_var_value(pSat, iVar) );
        // collect divisor literals
        Vec_IntClear( vTemp );
        Vec_IntPush( vTemp, Abc_LitNot(pLits[0]) ); // F = 0
        Vec_IntForEachEntry( vDivSet, iVar, i )
            Vec_IntPush( vTemp, sat_solver_var_literal(pSat, iVar) );
        // check against offset
        status = sat_solver_solve( pSat, Vec_IntArray(vTemp), Vec_IntArray(vTemp) + Vec_IntSize(vTemp), nBTLimit, 0, 0, 0 );
        if ( status == l_Undef )
            return SBD_SAT_UNDEC;
        if ( status == l_True )
            break;
        assert( status == l_False );
        // compute cube and add clause
        nFinal = sat_solver_final( pSat, &pFinal );
        uCube = ~(word)0;
        Vec_IntClear( vTemp );
        Vec_IntPush( vTemp, Abc_LitNot(pLits[1]) ); // NOT(iNewLit)
        for ( i = 0; i < nFinal; i++ )
        {
            if ( pFinal[i] == pLits[0] )
                continue;
            Vec_IntPush( vTemp, pFinal[i] );
            iVar = Vec_IntFind( vDivSet, Abc_Lit2Var(pFinal[i]) );   assert( iVar >= 0 );
            uCube &= Abc_LitIsCompl(pFinal[i]) ? s_Truths6[iVar] : ~s_Truths6[iVar];
        }
        uTruth |= uCube;
        status = sat_solver_addclause( pSat, Vec_IntArray(vTemp), Vec_IntArray(vTemp) + Vec_IntSize(vTemp) );
        assert( status );
        nIter++;
    }
    assert( status == l_True );
    // store the counter-example
    Vec_IntForEachEntry( vDivVars, iVar, i )
        Vec_IntAddToEntry( vDivValues, i, sat_solver_var_value(pSat, iVar) );

    for ( i = 0; i < Vec_IntSize(vDivValues); i++ )
        Vec_IntAddToEntry( vDivValues, i, 0xC );
/*
    // reduce the counter example
    for ( n = 0; n < 2; n++ )
    {
        Vec_IntClear( vTemp );
        Vec_IntPush( vTemp, Abc_Var2Lit(PivotVar, n) ); // n = 0 => F = 1  (expanding offset against onset)
        for ( i = 0; i < Vec_IntSize(vValues); i++ )
            Vec_IntPush( vTemp, Abc_Var2Lit(i, !((Vec_IntEntry(vValues, i) >> n) & 1)) );
        status = sat_solver_solve( pSat, Vec_IntArray(vTemp), Vec_IntArray(vTemp) + Vec_IntSize(vTemp), nBTLimit, 0, 0, 0 );
        assert( status == l_False );
        // compute cube and add clause
        nFinal = sat_solver_final( pSat, &pFinal );
        for ( i = 0; i < nFinal; i++ )
            if ( Abc_Lit2Var(pFinal[i]) != PivotVar )
                Vec_IntAddToEntry( vValues, Abc_Lit2Var(pFinal[i]), 1 << (n+2) );
    }
*/
    return SBD_SAT_SAT;
}

/**Function*************************************************************

  Synopsis    []

  Description []
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
int Sbd_ManSolve2( sat_solver * pSat, int PivotVar, int FreeVar, Vec_Int_t * vDivVars, Vec_Int_t * vDivValues, Vec_Int_t * vTemp, Vec_Int_t * vSop )
{
    int nBTLimit = 0;
    int status, i, iVar, nFinal, * pFinal, pLits[2], nIter = 0;
    assert( FreeVar < sat_solver_nvars(pSat) );
    assert( Vec_IntSize(vDivVars) == Vec_IntSize(vDivValues) );
    pLits[0] = Abc_Var2Lit( PivotVar, 0 ); // F = 1
    pLits[1] = Abc_Var2Lit( FreeVar, 0 );  // iNewLit
    Vec_IntClear( vSop );
    while ( 1 ) 
    {
        // find onset minterm
        status = sat_solver_solve( pSat, pLits, pLits + 2, nBTLimit, 0, 0, 0 );
        if ( status == l_Undef )
            return 0;
        if ( status == l_False )
            return 1;
        assert( status == l_True );
        // remember variable values
        //for ( i = 0; i < Vec_IntSize(vValues); i++ )
        //    Vec_IntWriteEntry( vValues, i, 2*sat_solver_var_value(pSat, i) );
        // collect divisor literals
        Vec_IntClear( vTemp );
        Vec_IntPush( vTemp, Abc_LitNot(pLits[0]) ); // F = 0
        //Vec_IntForEachEntry( vDivSet, iVar, i )
        Vec_IntForEachEntry( vDivVars, iVar, i )
            Vec_IntPush( vTemp, sat_solver_var_literal(pSat, iVar) );
        // check against offset
        status = sat_solver_solve( pSat, Vec_IntArray(vTemp), Vec_IntArray(vTemp) + Vec_IntSize(vTemp), nBTLimit, 0, 0, 0 );
        if ( status == l_Undef )
            return 0;
        if ( status == l_True )
            break;
        assert( status == l_False );
        // compute cube and add clause
        nFinal = sat_solver_final( pSat, &pFinal );
        Vec_IntClear( vTemp );
        Vec_IntPush( vTemp, Abc_LitNot(pLits[1]) ); // NOT(iNewLit)
        for ( i = 0; i < nFinal; i++ )
        {
            if ( pFinal[i] == pLits[0] )
                continue;
            Vec_IntPush( vTemp, pFinal[i] );
            iVar = Vec_IntFind( vDivVars, Abc_Lit2Var(pFinal[i]) );   assert( iVar >= 0 );
            //uCube &= Abc_LitIsCompl(pFinal[i]) ? s_Truths6[iVar] : ~s_Truths6[iVar];
            Vec_IntPush( vSop, Abc_Var2Lit( iVar, !Abc_LitIsCompl(pFinal[i]) ) );
        }
        //uTruth |= uCube;
        Vec_IntPush( vSop, -1 );
        status = sat_solver_addclause( pSat, Vec_IntArray(vTemp), Vec_IntArray(vTemp) + Vec_IntSize(vTemp) );
        assert( status );
        nIter++;
    }
    assert( status == l_True );
    // store the counter-example
    //for ( i = 0; i < Vec_IntSize(vValues); i++ )
    //    Vec_IntAddToEntry( vValues, i, sat_solver_var_value(pSat, i) );
    return 0;
}

word Sbd_ManSolverSupp( Vec_Int_t * vSop, int * pInds, int * pnVars )
{
    word Supp = 0;
    int i, Entry, nVars = 0;
    Vec_IntForEachEntry( vSop, Entry, i )
    {
        if ( Entry == -1 )
            continue;
        assert( Abc_Lit2Var(Entry) < 64 );
        if ( (Supp >> Abc_Lit2Var(Entry)) & 1 )
            continue;
        pInds[Abc_Lit2Var(Entry)] = nVars++;
        Supp |= (word)1 << Abc_Lit2Var(Entry);
    }
    *pnVars = nVars;
    return Supp;
}
void Sbd_ManSolverPrint( Vec_Int_t * vSop )
{
    int v, i, Entry, nVars, pInds[64];
    word Supp = Sbd_ManSolverSupp( vSop, pInds, &nVars );
    char Cube[65] = {'\0'};
    assert( Cube[nVars] == '\0' );
    for ( v = 0; v < nVars; v++ )
        Cube[v] = '-';
    Vec_IntForEachEntry( vSop, Entry, i )
    {
        if ( Entry == -1 )
        {
            printf( "%s\n", Cube );
            for ( v = 0; v < nVars; v++ )
                Cube[v] = '-';
            continue;
        }
        Cube[pInds[Abc_Lit2Var(Entry)]] = '1' - (char)Abc_LitIsCompl(Entry);
    }
    Supp = 0;
}
void Sbd_ManSolveSelect( Gia_Man_t * p, Vec_Int_t * vMirrors, int Pivot, Vec_Int_t * vDivVars, Vec_Int_t * vDivValues, Vec_Int_t * vWinObjs, Vec_Int_t * vObj2Var, Vec_Int_t * vTfo, Vec_Int_t * vRoots )
{
    Vec_Int_t * vSop = Vec_IntAlloc( 100 );
    Vec_Int_t * vTemp = Vec_IntAlloc( 100 );
    sat_solver * pSat = Sbd_ManSatSolver( NULL, p, vMirrors, Pivot, vWinObjs, vObj2Var, vTfo, vRoots, 0 );
    int PivotVar = Vec_IntEntry(vObj2Var, Pivot);
    int FreeVar = Vec_IntSize(vWinObjs) + Vec_IntSize(vTfo) + Vec_IntSize(vRoots);
    int Status = Sbd_ManSolve2( pSat, PivotVar, FreeVar, vDivVars, vDivValues, vTemp, vSop );
    printf( "Pivot = %4d. Divs = %4d.  ", Pivot, Vec_IntSize(vDivVars) );
    if ( Status == 0 )
        printf( "UNSAT.\n" );
    else
    {
        int nVars, pInds[64];
        word Supp = Sbd_ManSolverSupp( vSop, pInds, &nVars );
        //Sbd_ManSolverPrint( vSop );
        printf( "SAT with %d vars and %d cubes.\n", nVars, Vec_IntCountEntry(vSop, -1) );
        Supp = 0;
    }
    Vec_IntFree( vTemp );
    Vec_IntFree( vSop );
    sat_solver_delete( pSat );
}


/**Function*************************************************************

  Synopsis    [Returns a bunch of positive/negative random care minterms.]

  Description [Returns 0/1 if the functions is const 0/1.]
               
  SideEffects []

  SeeAlso     []

***********************************************************************/
static void sat_solver_random_polarity(sat_solver* s)
{
    int i, k;
    for ( i = 0; i < s->size; i += 64 )
    {
        word Polar = Gia_ManRandomW(0);
        for ( k = 0; k < 64 && (i << 6) + k < s->size; k++ )
            s->polarity[(i << 6) + k] = Abc_TtGetBit(&Polar, k);
    }
}
int Sbd_ManCollectConstants( sat_solver * pSat, int nCareMints[2], int PivotVar, word * pVarSims[], Vec_Int_t * vInds )
{
    int nBTLimit = 0;
    int i, Ind; 
    assert( Vec_IntSize(vInds) == nCareMints[0] + nCareMints[1] );
    Vec_IntForEachEntry( vInds, Ind, i )
    {
        int fOffSet = (int)(i < nCareMints[0]);
        int status, k, iLit = Abc_Var2Lit( PivotVar, fOffSet );
        sat_solver_random_polarity( pSat );
        status = sat_solver_solve( pSat, &iLit, &iLit + 1, nBTLimit, 0, 0, 0 );
        if ( status == l_Undef )
            return -2;
        if ( status == l_False )
            return fOffSet;
        for ( k = 0; k <= PivotVar; k++ )
            if ( Abc_TtGetBit(pVarSims[k], Ind) != sat_solver_var_value(pSat, k) )
                Abc_TtXorBit(pVarSims[k], Ind);
    }
    return -1;
}

int Sbd_ManCollectConstantsNew( sat_solver * pSat, Vec_Int_t * vDivVars, int nConsts, int PivotVar, word * pOnset, word * pOffset )
{
    int nBTLimit = 0;
    int n, i, k, status, iLit, iVar; 
    word * pPats[2] = {pOnset, pOffset};
    assert( Vec_IntSize(vDivVars) < 64 );
    for ( n = 0; n < 2; n++ )
    for ( i = 0; i < nConsts; i++ )
    {
        sat_solver_random_polarity( pSat );
        iLit = Abc_Var2Lit( PivotVar, n );
        status = sat_solver_solve( pSat, &iLit, &iLit + 1, nBTLimit, 0, 0, 0 );
        if ( status == l_Undef )
            return -2;
        if ( status == l_False )
            return n;
        pPats[n][i] = ((word)!n) << Vec_IntSize(vDivVars);
        Vec_IntForEachEntry( vDivVars, iVar, k )
            if ( sat_solver_var_value(pSat, iVar) )
                Abc_TtXorBit(&pPats[n][i], k);
    }
    return -1;
}


////////////////////////////////////////////////////////////////////////
///                       END OF FILE                                ///
////////////////////////////////////////////////////////////////////////


ABC_NAMESPACE_IMPL_END