/******************************************************************************
 * $Id: ogrdgnlayer.cpp,v 1.37 2006/03/02 05:38:41 fwarmerdam Exp $
 *
 * Project:  OpenGIS Simple Features Reference Implementation
 * Purpose:  Implements OGRDGNLayer class.
 * Author:   Frank Warmerdam, warmerdam@pobox.com
 *
 ******************************************************************************
 * Copyright (c) 2000, Frank Warmerdam (warmerdam@pobox.com)
 *
 * 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 copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * 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.
 ******************************************************************************
 *
 * $Log: ogrdgnlayer.cpp,v $
 * Revision 1.37  2006/03/02 05:38:41  fwarmerdam
 * Added support for writing geometry collections
 *
 * Revision 1.36  2006/01/20 17:45:40  fwarmerdam
 * Updated to new DGNCreateComplexHeaderFromGroup arg list.
 *
 * Revision 1.35  2005/09/21 01:00:46  fwarmerdam
 * fixup OGRFeatureDefn and OGRSpatialReference refcount handling
 *
 * Revision 1.34  2005/07/20 02:33:03  fwarmerdam
 * Set feature geometry dimension based on source file.
 *
 * Revision 1.33  2005/02/22 12:54:50  fwarmerdam
 * use OGRLayer base spatial filter support
 *
 * Revision 1.32  2005/02/02 21:09:44  fwarmerdam
 * track m_nFeaturesRead
 *
 * Revision 1.31  2004/02/24 14:24:08  warmerda
 * Fixed a bug where 0/0 linkages terminated all other linkages on an element.
 *
 * Revision 1.30  2004/02/23 21:45:03  warmerda
 * added support for various link formats
 *
 * Revision 1.29  2003/11/27 14:15:20  warmerda
 * added surface type in createcomplexheaderfromgroup call
 *
 * Revision 1.28  2003/09/29 14:25:30  warmerda
 * Fixed memory leak as reported by Steve Brooks.
 *
 * Revision 1.27  2003/05/21 03:42:01  warmerda
 * Expanded tabs
 *
 * Revision 1.26  2003/05/15 14:47:24  warmerda
 * implement quaternion support on write
 *
 * Revision 1.25  2003/05/12 18:48:57  warmerda
 * added preliminary 3D write support
 *
 * Revision 1.24  2003/01/02 21:45:23  warmerda
 * move OGRBuildPolygonsFromEdges into C API
 */

#include "ogr_dgn.h"
#include "cpl_conv.h"
#include "ogr_featurestyle.h"
#include "ogr_api.h"

CPL_CVSID("$Id: ogrdgnlayer.cpp,v 1.37 2006/03/02 05:38:41 fwarmerdam Exp $");

/************************************************************************/
/*                           OGRDGNLayer()                              */
/************************************************************************/

OGRDGNLayer::OGRDGNLayer( const char * pszName, DGNHandle hDGN,
                          int bUpdate )
    
{
    this->hDGN = hDGN;
    this->bUpdate = bUpdate;

/* -------------------------------------------------------------------- */
/*      Work out what link format we are using.                         */
/* -------------------------------------------------------------------- */
    OGRFieldType eLinkFieldType;

    pszLinkFormat = (char *) CPLGetConfigOption( "DGN_LINK_FORMAT", "FIRST" );
    if( EQUAL(pszLinkFormat,"FIRST") )
        eLinkFieldType = OFTInteger;
    else if( EQUAL(pszLinkFormat,"LIST") )
        eLinkFieldType = OFTIntegerList;
    else if( EQUAL(pszLinkFormat,"STRING") )
        eLinkFieldType = OFTString;
    else
    {
        CPLError( CE_Warning, CPLE_AppDefined, 
                  "DGN_LINK_FORMAT=%s, but only FIRST, LIST or STRING supported.",
                  pszLinkFormat );
        pszLinkFormat = "FIRST";
        eLinkFieldType = OFTInteger;
    }
    pszLinkFormat = CPLStrdup(pszLinkFormat);

/* -------------------------------------------------------------------- */
/*      Create the feature definition.                                  */
/* -------------------------------------------------------------------- */
    poFeatureDefn = new OGRFeatureDefn( pszName );
    poFeatureDefn->Reference();
    
    OGRFieldDefn        oField( "", OFTInteger );

/* -------------------------------------------------------------------- */
/*      Element type                                                    */
/* -------------------------------------------------------------------- */
    oField.SetName( "Type" );
    oField.SetType( OFTInteger );
    oField.SetWidth( 2 );
    oField.SetPrecision( 0 );
    poFeatureDefn->AddFieldDefn( &oField );

/* -------------------------------------------------------------------- */
/*      Level number.                                                   */
/* -------------------------------------------------------------------- */
    oField.SetName( "Level" );
    oField.SetType( OFTInteger );
    oField.SetWidth( 2 );
    oField.SetPrecision( 0 );
    poFeatureDefn->AddFieldDefn( &oField );

/* -------------------------------------------------------------------- */
/*      graphic group                                                   */
/* -------------------------------------------------------------------- */
    oField.SetName( "GraphicGroup" );
    oField.SetType( OFTInteger );
    oField.SetWidth( 4 );
    oField.SetPrecision( 0 );
    poFeatureDefn->AddFieldDefn( &oField );

/* -------------------------------------------------------------------- */
/*      ColorIndex                                                      */
/* -------------------------------------------------------------------- */
    oField.SetName( "ColorIndex" );
    oField.SetType( OFTInteger );
    oField.SetWidth( 3 );
    oField.SetPrecision( 0 );
    poFeatureDefn->AddFieldDefn( &oField );

/* -------------------------------------------------------------------- */
/*      Weight                                                          */
/* -------------------------------------------------------------------- */
    oField.SetName( "Weight" );
    oField.SetType( OFTInteger );
    oField.SetWidth( 2 );
    oField.SetPrecision( 0 );
    poFeatureDefn->AddFieldDefn( &oField );

/* -------------------------------------------------------------------- */
/*      Style                                                           */
/* -------------------------------------------------------------------- */
    oField.SetName( "Style" );
    oField.SetType( OFTInteger );
    oField.SetWidth( 1 );
    oField.SetPrecision( 0 );
    poFeatureDefn->AddFieldDefn( &oField );

/* -------------------------------------------------------------------- */
/*      EntityNum                                                       */
/* -------------------------------------------------------------------- */
    oField.SetName( "EntityNum" );
    oField.SetType( eLinkFieldType );
    oField.SetWidth( 0 );
    oField.SetPrecision( 0 );
    poFeatureDefn->AddFieldDefn( &oField );

/* -------------------------------------------------------------------- */
/*      MSLink                                                          */
/* -------------------------------------------------------------------- */
    oField.SetName( "MSLink" );
    oField.SetType( eLinkFieldType );
    oField.SetWidth( 0 );
    oField.SetPrecision( 0 );
    poFeatureDefn->AddFieldDefn( &oField );

/* -------------------------------------------------------------------- */
/*      Text                                                            */
/* -------------------------------------------------------------------- */
    oField.SetName( "Text" );
    oField.SetType( OFTString );
    oField.SetWidth( 0 );
    oField.SetPrecision( 0 );
    poFeatureDefn->AddFieldDefn( &oField );

/* -------------------------------------------------------------------- */
/*      Create template feature for evaluating simple expressions.      */
/* -------------------------------------------------------------------- */
    bHaveSimpleQuery = FALSE;
    poEvalFeature = new OGRFeature( poFeatureDefn );

    /* TODO: I am intending to keep track of simple attribute queries (ones
       using only FID, Type and Level and short circuiting their operation
       based on the index.  However, there are some complexities with
       complex elements, and spatial queries that have caused me to put it
       off for now.
    */
}

/************************************************************************/
/*                           ~OGRDGNLayer()                             */
/************************************************************************/

OGRDGNLayer::~OGRDGNLayer()

{
    if( m_nFeaturesRead > 0 && poFeatureDefn != NULL )
    {
        CPLDebug( "Mem", "%d features read on layer '%s'.",
                  (int) m_nFeaturesRead, 
                  poFeatureDefn->GetName() );
    }

    delete poEvalFeature;

    poFeatureDefn->Release();

    CPLFree( pszLinkFormat );
}

/************************************************************************/
/*                          SetSpatialFilter()                          */
/************************************************************************/

void OGRDGNLayer::SetSpatialFilter( OGRGeometry * poGeomIn )

{
    if( !InstallFilter(poGeomIn) )
        return;

    if( m_poFilterGeom != NULL )
    {
        DGNSetSpatialFilter( hDGN, 
                             m_sFilterEnvelope.MinX, 
                             m_sFilterEnvelope.MinY, 
                             m_sFilterEnvelope.MaxX, 
                             m_sFilterEnvelope.MaxY );
    }
    else
    {
        DGNSetSpatialFilter( hDGN, 0.0, 0.0, 0.0, 0.0 );
    }

    ResetReading();
}

/************************************************************************/
/*                            ResetReading()                            */
/************************************************************************/

void OGRDGNLayer::ResetReading()

{
    iNextShapeId = 0;
    DGNRewind( hDGN );
}

/************************************************************************/
/*                             GetFeature()                             */
/************************************************************************/

OGRFeature *OGRDGNLayer::GetFeature( long nFeatureId )

{
    OGRFeature *poFeature;
    DGNElemCore *psElement;

    if( !DGNGotoElement( hDGN, nFeatureId ) )
        return NULL;

    // We should likely clear the spatial search region as it affects 
    // DGNReadElement() but I will defer that for now. 

    psElement = DGNReadElement( hDGN );
    poFeature = ElementToFeature( psElement );
    DGNFreeElement( hDGN, psElement );

    if( poFeature == NULL )
        return NULL;

    if( poFeature->GetFID() != nFeatureId )
    {
        delete poFeature;
        return NULL;
    }

    return poFeature;
}

/************************************************************************/
/*                           ConsiderBrush()                            */
/*                                                                      */
/*      Method to set the style for a polygon, including a brush if     */
/*      appropriate.                                                    */
/************************************************************************/

void OGRDGNLayer::ConsiderBrush( DGNElemCore *psElement, const char *pszPen,
                                 OGRFeature *poFeature )

{
    int         gv_red, gv_green, gv_blue;
    char                szFullStyle[256];
    int                 nFillColor;

    if( DGNGetShapeFillInfo( hDGN, psElement, &nFillColor ) 
        && DGNLookupColor( hDGN, nFillColor, 
                           &gv_red, &gv_green, &gv_blue ) )
    {
        sprintf( szFullStyle, 
                 "BRUSH(fc:#%02x%02x%02x,id:\"ogr-brush-0\")",
                 gv_red, gv_green, gv_blue );
              
        if( nFillColor != psElement->color )
        {
            strcat( szFullStyle, ";" );
            strcat( szFullStyle, pszPen );
        }
        poFeature->SetStyleString( szFullStyle );
    }
    else
        poFeature->SetStyleString( pszPen );
}

/************************************************************************/
/*                          ElementToFeature()                          */
/************************************************************************/

OGRFeature *OGRDGNLayer::ElementToFeature( DGNElemCore *psElement )

{
    OGRFeature  *poFeature = new OGRFeature( poFeatureDefn );

    poFeature->SetFID( psElement->element_id );
    poFeature->SetField( "Type", psElement->type );
    poFeature->SetField( "Level", psElement->level );
    poFeature->SetField( "GraphicGroup", psElement->graphic_group );
    poFeature->SetField( "ColorIndex", psElement->color );
    poFeature->SetField( "Weight", psElement->weight );
    poFeature->SetField( "Style", psElement->style );
    

    m_nFeaturesRead++;

/* -------------------------------------------------------------------- */
/*      Collect linkage information                                     */
/* -------------------------------------------------------------------- */
#define MAX_LINK 100    
    int anEntityNum[MAX_LINK], anMSLink[MAX_LINK];
    unsigned char *pabyData;
    int iLink=0, nLinkCount=0;

    anEntityNum[0] = 0;
    anMSLink[0] = 0;

    pabyData = DGNGetLinkage( hDGN, psElement, iLink, NULL, 
                              anEntityNum+iLink, anMSLink+iLink, NULL );
    while( pabyData && nLinkCount < MAX_LINK )
    {
        iLink++;

        if( anEntityNum[nLinkCount] != 0 || anMSLink[nLinkCount] != 0 )
            nLinkCount++;

        anEntityNum[nLinkCount] = 0;
        anMSLink[nLinkCount] = 0;

        pabyData = DGNGetLinkage( hDGN, psElement, iLink, NULL, 
                                  anEntityNum+nLinkCount, anMSLink+nLinkCount, 
                                  NULL );
    }

/* -------------------------------------------------------------------- */
/*      Apply attribute linkage to feature.                             */
/* -------------------------------------------------------------------- */
    if( nLinkCount > 0 )
    {
        if( EQUAL(pszLinkFormat,"FIRST") )
        {
            poFeature->SetField( "EntityNum", anEntityNum[0] );
            poFeature->SetField( "MSLink", anMSLink[0] );
        }
        else if( EQUAL(pszLinkFormat,"LIST") )
        {
            poFeature->SetField( "EntityNum", nLinkCount, anEntityNum );
            poFeature->SetField( "MSLink", nLinkCount, anMSLink );
        }
        else if( EQUAL(pszLinkFormat,"STRING") )
        {
            char szEntityList[MAX_LINK*9], szMSLinkList[MAX_LINK*9];
            int nEntityLen = 0, nMSLinkLen = 0;

            for( iLink = 0; iLink < nLinkCount; iLink++ )
            {
                if( iLink != 0 )
                {
                    szEntityList[nEntityLen++] = ',';
                    szMSLinkList[nMSLinkLen++] = ',';
                }

                sprintf( szEntityList + nEntityLen, "%d", anEntityNum[iLink]);
                sprintf( szMSLinkList + nMSLinkLen, "%d", anMSLink[iLink] );
                
                nEntityLen += strlen(szEntityList + nEntityLen );
                nMSLinkLen += strlen(szMSLinkList + nMSLinkLen );
            }

            poFeature->SetField( "EntityNum", szEntityList );
            poFeature->SetField( "MSLink", szMSLinkList );
        }
    }

/* -------------------------------------------------------------------- */
/*      Lookup color.                                                   */
/* -------------------------------------------------------------------- */
    char        gv_color[128];
    int         gv_red, gv_green, gv_blue;
    char        szFSColor[128], szPen[256];

    szFSColor[0] = '\0';
    if( DGNLookupColor( hDGN, psElement->color, 
                        &gv_red, &gv_green, &gv_blue ) )
    {
        sprintf( gv_color, "%f %f %f 1.0", 
                 gv_red / 255.0, gv_green / 255.0, gv_blue / 255.0 );

        sprintf( szFSColor, "c:#%02x%02x%02x", 
                 gv_red, gv_green, gv_blue );
    }

/* -------------------------------------------------------------------- */
/*      Generate corresponding PEN style.                               */
/* -------------------------------------------------------------------- */
    if( psElement->style == DGNS_SOLID )
        sprintf( szPen, "PEN(id:\"ogr-pen-0\"" );
    else if( psElement->style == DGNS_DOTTED )
        sprintf( szPen, "PEN(id:\"ogr-pen-5\"" );
    else if( psElement->style == DGNS_MEDIUM_DASH )
        sprintf( szPen, "PEN(id:\"ogr-pen-2\"" );
    else if( psElement->style == DGNS_LONG_DASH )
        sprintf( szPen, "PEN(id:\"ogr-pen-4\"" );
    else if( psElement->style == DGNS_DOT_DASH )
        sprintf( szPen, "PEN(id:\"ogr-pen-6\"" );
    else if( psElement->style == DGNS_SHORT_DASH )
        sprintf( szPen, "PEN(id:\"ogr-pen-3\"" );
    else if( psElement->style == DGNS_DASH_DOUBLE_DOT )
        sprintf( szPen, "PEN(id:\"ogr-pen-7\"" );
    else if( psElement->style == DGNS_LONG_DASH_SHORT_DASH )
        sprintf( szPen, "PEN(p:\"10px 5px 4px 5px\"" );
    else
        sprintf( szPen, "PEN(id:\"ogr-pen-0\"" );

    if( strlen(szFSColor) > 0 )
        sprintf( szPen+strlen(szPen), ",%s", szFSColor );

    if( psElement->weight > 1 )
        sprintf( szPen+strlen(szPen), ",w:%dpx", psElement->weight );
        
    strcat( szPen, ")" );

    switch( psElement->stype )
    {
      case DGNST_MULTIPOINT:
        if( psElement->type == DGNT_SHAPE )
        {
            OGRLinearRing       *poLine = new OGRLinearRing();
            OGRPolygon          *poPolygon = new OGRPolygon();
            DGNElemMultiPoint *psEMP = (DGNElemMultiPoint *) psElement;
            
            poLine->setNumPoints( psEMP->num_vertices );
            for( int i = 0; i < psEMP->num_vertices; i++ )
            {
                poLine->setPoint( i, 
                                  psEMP->vertices[i].x,
                                  psEMP->vertices[i].y,
                                  psEMP->vertices[i].z );
            }

            poPolygon->addRingDirectly( poLine );

            poFeature->SetGeometryDirectly( poPolygon );

            ConsiderBrush( psElement, szPen, poFeature );
        }
        else if( psElement->type == DGNT_CURVE )
        {
            DGNElemMultiPoint *psEMP = (DGNElemMultiPoint *) psElement;
            OGRLineString       *poLine = new OGRLineString();
            DGNPoint            *pasPoints;
            int                 nPoints;

            nPoints = 5 * psEMP->num_vertices;
            pasPoints = (DGNPoint *) CPLMalloc(sizeof(DGNPoint) * nPoints);
            
            DGNStrokeCurve( hDGN, psEMP, nPoints, pasPoints );

            poLine->setNumPoints( nPoints );
            for( int i = 0; i < nPoints; i++ )
            {
                poLine->setPoint( i, 
                                  pasPoints[i].x,
                                  pasPoints[i].y,
                                  pasPoints[i].z );
            }

            poFeature->SetGeometryDirectly( poLine );
            CPLFree( pasPoints );

            poFeature->SetStyleString( szPen );
        }
        else
        {
            OGRLineString       *poLine = new OGRLineString();
            DGNElemMultiPoint *psEMP = (DGNElemMultiPoint *) psElement;
            
            if( psEMP->num_vertices > 0 )
            {
                poLine->setNumPoints( psEMP->num_vertices );
                for( int i = 0; i < psEMP->num_vertices; i++ )
                {
                    poLine->setPoint( i, 
                                      psEMP->vertices[i].x,
                                      psEMP->vertices[i].y,
                                      psEMP->vertices[i].z );
                }
                
                poFeature->SetGeometryDirectly( poLine );
            }

            poFeature->SetStyleString( szPen );
        }
        break;

      case DGNST_ARC:
      {
          OGRLineString *poLine = new OGRLineString();
          DGNElemArc    *psArc = (DGNElemArc *) psElement;
          DGNPoint      asPoints[90];
          int           nPoints;

          nPoints = (int) (MAX(1,ABS(psArc->sweepang) / 5) + 1);
          DGNStrokeArc( hDGN, psArc, nPoints, asPoints );

          poLine->setNumPoints( nPoints );
          for( int i = 0; i < nPoints; i++ )
          {
              poLine->setPoint( i, 
                                asPoints[i].x,
                                asPoints[i].y,
                                asPoints[i].z );
          }

          poFeature->SetGeometryDirectly( poLine );
          poFeature->SetStyleString( szPen );
      }
      break;

      case DGNST_TEXT:
      {
          OGRPoint      *poPoint = new OGRPoint();
          DGNElemText   *psText = (DGNElemText *) psElement;
          char          *pszOgrFS;

          poPoint->setX( psText->origin.x );
          poPoint->setY( psText->origin.y );
          poPoint->setZ( psText->origin.z );

          poFeature->SetGeometryDirectly( poPoint );

          pszOgrFS = (char *) CPLMalloc(strlen(psText->string) + 150);

          // setup the basic label.
          sprintf( pszOgrFS, "LABEL(t:\"%s\"",  psText->string );

          // set the color if we have it. 
          if( strlen(szFSColor) > 0 )
              sprintf( pszOgrFS+strlen(pszOgrFS), ",%s", szFSColor );

          // Add the size info in ground units.
          if( ABS(psText->height_mult) >= 6.0 )
              sprintf( pszOgrFS+strlen(pszOgrFS), ",s:%dg", 
                       (int) psText->height_mult );
          else if( ABS(psText->height_mult) > 0.1 )
              sprintf( pszOgrFS+strlen(pszOgrFS), ",s:%.3fg", 
                       psText->height_mult );
          else
              sprintf( pszOgrFS+strlen(pszOgrFS), ",s:%.12fg", 
                       psText->height_mult );

          // Add the angle, if not horizontal
          if( psText->rotation != 0.0 )
              sprintf( pszOgrFS+strlen(pszOgrFS), ",a:%d", 
                       (int) (psText->rotation+0.5) );

          strcat( pszOgrFS, ")" );

          poFeature->SetStyleString( pszOgrFS );
          CPLFree( pszOgrFS );

          poFeature->SetField( "Text", psText->string );
      }
      break;

      case DGNST_COMPLEX_HEADER:
      {
          DGNElemComplexHeader *psHdr = (DGNElemComplexHeader *) psElement;
          int           iChild;
          OGRMultiLineString  oChildren;

          /* collect subsequent child geometries. */
          // we should disable the spatial filter ... add later.
          for( iChild = 0; iChild < psHdr->numelems; iChild++ )
          {
              OGRFeature *poChildFeature = NULL;
              DGNElemCore *psChildElement;

              psChildElement = DGNReadElement( hDGN );
              // should verify complex bit set, not another header.

              if( psChildElement != NULL )
              {
                  poChildFeature = ElementToFeature( psChildElement );
                  DGNFreeElement( hDGN, psChildElement );
              }

              if( poChildFeature != NULL
                  && poChildFeature->GetGeometryRef() != NULL )
              {
                  OGRGeometry *poGeom;

                  poGeom = poChildFeature->GetGeometryRef();
                  if( wkbFlatten(poGeom->getGeometryType()) == wkbLineString )
                      oChildren.addGeometry( poGeom );
              }

              if( poChildFeature != NULL )
                  delete poChildFeature;
          }

          // Try to assemble into polygon geometry.
          OGRGeometry *poGeom;

          if( psElement->type == DGNT_COMPLEX_SHAPE_HEADER )
              poGeom = (OGRPolygon *) 
                  OGRBuildPolygonFromEdges( (OGRGeometryH) &oChildren, 
                                            TRUE, TRUE, 100000, NULL );
          else
              poGeom = oChildren.clone();

          if( poGeom != NULL )
              poFeature->SetGeometryDirectly( poGeom );

          ConsiderBrush( psElement, szPen, poFeature );
      }
      break;

      default:
        break;
    }
    
/* -------------------------------------------------------------------- */
/*      Fixup geometry dimension.                                       */
/* -------------------------------------------------------------------- */
    if( poFeature->GetGeometryRef() != NULL )
        poFeature->GetGeometryRef()->setCoordinateDimension( 
            DGNGetDimension( hDGN ) );

    return poFeature;
}

/************************************************************************/
/*                           GetNextFeature()                           */
/************************************************************************/

OGRFeature *OGRDGNLayer::GetNextFeature()

{
    DGNElemCore *psElement;

    DGNGetElementIndex( hDGN, NULL );

    while( (psElement = DGNReadElement( hDGN )) != NULL )
    {
        OGRFeature      *poFeature;

        if( psElement->deleted )
        {
            DGNFreeElement( hDGN, psElement );
            continue;
        }

        poFeature = ElementToFeature( psElement );
        DGNFreeElement( hDGN, psElement );

        if( poFeature == NULL )
            continue;

        if( poFeature->GetGeometryRef() == NULL )
        {
            delete poFeature;
            continue;
        }

        if( (m_poAttrQuery == NULL
             || m_poAttrQuery->Evaluate( poFeature ))
            && FilterGeometry( poFeature->GetGeometryRef() ) )
            return poFeature;

        delete poFeature;
    }        

    return NULL;
}

/************************************************************************/
/*                           TestCapability()                           */
/************************************************************************/

int OGRDGNLayer::TestCapability( const char * pszCap )

{
    if( EQUAL(pszCap,OLCRandomRead) )
        return TRUE;

    else if( EQUAL(pszCap,OLCSequentialWrite) )
        return bUpdate;
    else if( EQUAL(pszCap,OLCRandomWrite) )
        return FALSE; /* maybe later? */

    else if( EQUAL(pszCap,OLCFastFeatureCount) )
        return m_poFilterGeom == NULL || m_poAttrQuery == NULL;

    else if( EQUAL(pszCap,OLCFastSpatialFilter) )
        return FALSE;

    else if( EQUAL(pszCap,OLCFastGetExtent) )
        return TRUE;

    else 
        return FALSE;
}

/************************************************************************/
/*                          GetFeatureCount()                           */
/************************************************************************/

int OGRDGNLayer::GetFeatureCount( int bForce )

{
/* -------------------------------------------------------------------- */
/*      If any odd conditions are in effect collect the information     */
/*      normally.                                                       */
/* -------------------------------------------------------------------- */
    if( m_poFilterGeom != NULL || m_poAttrQuery != NULL )
        return OGRLayer::GetFeatureCount( bForce );

/* -------------------------------------------------------------------- */
/*      Otherwise scan the index.                                       */
/* -------------------------------------------------------------------- */
    int nElementCount, i, nFeatureCount = 0;
    int bInComplexShape = FALSE;
    const DGNElementInfo *pasIndex = DGNGetElementIndex(hDGN,&nElementCount);

    for( i = 0; i < nElementCount; i++ )
    {
        if( pasIndex[i].flags & DGNEIF_DELETED )
            continue;

        switch( pasIndex[i].stype )
        {
          case DGNST_MULTIPOINT:
          case DGNST_ARC:
          case DGNST_TEXT:
            if( !(pasIndex[i].flags & DGNEIF_COMPLEX) || !bInComplexShape )
            {
                nFeatureCount++;
                bInComplexShape = FALSE;
            }
            break;

          case DGNST_COMPLEX_HEADER:
            nFeatureCount++;
            bInComplexShape = TRUE;
            break;

          default:
            break;
        }
    }

    return nFeatureCount;
}

/************************************************************************/
/*                             GetExtent()                              */
/************************************************************************/

OGRErr OGRDGNLayer::GetExtent( OGREnvelope *psExtent, int bForce )

{
    double      adfExtents[6];

    if( !DGNGetExtents( hDGN, adfExtents ) )
        return OGRERR_FAILURE;
    
    psExtent->MinX = adfExtents[0];
    psExtent->MinY = adfExtents[1];
    psExtent->MaxX = adfExtents[3];
    psExtent->MaxY = adfExtents[4];
    
    return OGRERR_NONE;
}

/************************************************************************/
/*                      LineStringToElementGroup()                      */
/*                                                                      */
/*      Convert an OGR line string to one or more DGN elements.  If     */
/*      the input is too long for a single element (more than 38        */
/*      points) we split it into multiple LINE_STRING elements, and     */
/*      prefix with a complex group header element.                     */
/*                                                                      */
/*      This method can create handle creating shapes, or line          */
/*      strings for the aggregate object, but the components of a       */
/*      complex shape group are always line strings.                    */
/************************************************************************/

#define MAX_ELEM_POINTS 38

DGNElemCore **OGRDGNLayer::LineStringToElementGroup( OGRLineString *poLS,
                                                     int nGroupType )

{
    int nTotalPoints = poLS->getNumPoints();
    int iNextPoint = 0, iGeom = 0;
    DGNElemCore **papsGroup;

    papsGroup = (DGNElemCore **) 
        CPLCalloc( sizeof(void*), (nTotalPoints/(MAX_ELEM_POINTS-1))+3 );

    for( iNextPoint = 0; iNextPoint < nTotalPoints;  )
    {
        DGNPoint asPoints[38];
        int nThisCount = 0;

        // we need to repeat end points of elements.
        if( iNextPoint != 0 )
            iNextPoint--;

        for( ; iNextPoint < nTotalPoints && nThisCount < MAX_ELEM_POINTS; 
             iNextPoint++, nThisCount++ )
        {
            asPoints[nThisCount].x = poLS->getX( iNextPoint );
            asPoints[nThisCount].y = poLS->getY( iNextPoint );
            asPoints[nThisCount].z = poLS->getZ( iNextPoint );
        }
        
        if( nTotalPoints <= MAX_ELEM_POINTS )
            papsGroup[0] = DGNCreateMultiPointElem( hDGN, nGroupType,
                                                 nThisCount, asPoints);
        else
            papsGroup[++iGeom] = 
                DGNCreateMultiPointElem( hDGN, DGNT_LINE_STRING,
                                         nThisCount, asPoints);
    }

/* -------------------------------------------------------------------- */
/*      We needed to make into a group.  Create the complex header      */
/*      from the rest of the group.                                     */
/* -------------------------------------------------------------------- */
    if( papsGroup[0] == NULL )
    {
        if( nGroupType == DGNT_SHAPE )
            nGroupType = DGNT_COMPLEX_SHAPE_HEADER;
        else
            nGroupType = DGNT_COMPLEX_CHAIN_HEADER;
        
        papsGroup[0] = 
            DGNCreateComplexHeaderFromGroup( hDGN, nGroupType, 
                                             iGeom, papsGroup + 1 );
    }

    return papsGroup;
}

/************************************************************************/
/*                           TranslateLabel()                           */
/*                                                                      */
/*      Translate LABEL feature.                                        */
/************************************************************************/

DGNElemCore **OGRDGNLayer::TranslateLabel( OGRFeature *poFeature )

{
    DGNElemCore **papsGroup;
    OGRPoint *poPoint = (OGRPoint *) poFeature->GetGeometryRef();
    OGRStyleMgr oMgr;
    OGRStyleLabel *poLabel;
    const char *pszText = poFeature->GetFieldAsString( "Text" );
    double dfRotation = 0.0;
    double dfCharHeight = 100.0;

    oMgr.InitFromFeature( poFeature );
    poLabel = (OGRStyleLabel *) oMgr.GetPart( 0 );
    if( poLabel != NULL && poLabel->GetType() != OGRSTCLabel )
    {
        delete poLabel;
        poLabel = NULL;
    }

    if( poLabel != NULL )
    {
        GBool bDefault;

        if( poLabel->TextString(bDefault) != NULL && !bDefault )
            pszText = poLabel->TextString(bDefault);
        dfRotation = poLabel->Angle(bDefault);

        poLabel->Size( bDefault );
        if( !bDefault && poLabel->GetUnit() == OGRSTUGround )
            dfCharHeight = poLabel->Size(bDefault);
        // this part is really kind of bogus.
        if( !bDefault && poLabel->GetUnit() == OGRSTUMM )
            dfCharHeight = poLabel->Size(bDefault)/1000.0;

        /* poLabel->ForeColor(); */

        /* get font id */
    }

    papsGroup = (DGNElemCore **) CPLCalloc(sizeof(void*),2);
    papsGroup[0] = 
        DGNCreateTextElem( hDGN, pszText, 0, DGNJ_LEFT_BOTTOM, 
                           dfCharHeight, dfCharHeight, dfRotation, NULL,
                           poPoint->getX(), 
                           poPoint->getY(), 
                           poPoint->getZ() );

    return papsGroup;
}

/************************************************************************/
/*                           CreateFeature()                            */
/*                                                                      */
/*      Create a new feature and write to file.                         */
/************************************************************************/

OGRErr OGRDGNLayer::CreateFeature( OGRFeature *poFeature )

{
    if( !bUpdate )
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "Attempt to create feature on read-only DGN file." );
        return OGRERR_FAILURE;
    }
    
    if( poFeature->GetGeometryRef() == NULL )
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "Features with empty, geometry collection geometries not\n"
                  "supported in DGN format." );
        return OGRERR_FAILURE;
    }

    return CreateFeatureWithGeom( poFeature, poFeature->GetGeometryRef() );
}

/************************************************************************/
/*                       CreateFeatureWithGeom()                        */
/*                                                                      */
/*      Create an element or element group from a given geometry and    */
/*      the given feature.  This method recurses to handle              */
/*      collections as essentially independent features.                */
/************************************************************************/

OGRErr OGRDGNLayer::CreateFeatureWithGeom( OGRFeature *poFeature,
                                           OGRGeometry *poGeom)

{
/* -------------------------------------------------------------------- */
/*      Translate the geometry.                                         */
/* -------------------------------------------------------------------- */
    DGNElemCore **papsGroup = NULL;
    int i;
    const char *pszStyle = poFeature->GetStyleString();

    if( wkbFlatten(poGeom->getGeometryType()) == wkbPoint )
    {
        OGRPoint *poPoint = (OGRPoint *) poGeom;
        const char *pszText = poFeature->GetFieldAsString("Text");

        if( (pszText == NULL || strlen(pszText) == 0)
            && (pszStyle == NULL || strstr(pszStyle,"LABEL") == NULL) )
        {
            DGNPoint asPoints[2];

            papsGroup = (DGNElemCore **) CPLCalloc(sizeof(void*),2);

            // Treat a non text point as a degenerate line.
            asPoints[0].x = poPoint->getX();
            asPoints[0].y = poPoint->getY();
            asPoints[0].z = poPoint->getZ();
            asPoints[1] = asPoints[0];
            
            papsGroup[0] = DGNCreateMultiPointElem( hDGN, DGNT_LINE, 
                                                    2, asPoints );
        }
        else
        {
            papsGroup = TranslateLabel( poFeature );
        }
    }
    else if( wkbFlatten(poGeom->getGeometryType()) == wkbLineString )
    {
        papsGroup = LineStringToElementGroup( (OGRLineString *) poGeom, 
                                              DGNT_LINE_STRING );
    }
    else if( wkbFlatten(poGeom->getGeometryType()) == wkbPolygon )
    {
        OGRPolygon *poPoly = ((OGRPolygon *) poGeom);

        // Ignore all but the exterior ring. 
        papsGroup = LineStringToElementGroup( poPoly->getExteriorRing(),
                                              DGNT_SHAPE );
    }
    else if( wkbFlatten(poGeom->getGeometryType()) == wkbMultiPolygon 
             || wkbFlatten(poGeom->getGeometryType()) == wkbMultiPoint
             || wkbFlatten(poGeom->getGeometryType()) == wkbMultiLineString
             || wkbFlatten(poGeom->getGeometryType()) == wkbGeometryCollection)
    {
        OGRGeometryCollection *poGC = (OGRGeometryCollection *) poGeom;
        int iGeom;

        for( iGeom = 0; iGeom < poGC->getNumGeometries(); iGeom++ )
        {
            OGRErr eErr = CreateFeatureWithGeom( poFeature, 
                                                 poGC->getGeometryRef(iGeom) );
            if( eErr != OGRERR_NONE )
                return eErr;
        }

        return OGRERR_NONE;
    }
    else
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "Unsupported geometry type (%s) for DGN.",
                  OGRGeometryTypeToName( poGeom->getGeometryType() ) );
        return OGRERR_FAILURE;
    }

/* -------------------------------------------------------------------- */
/*      Add other attributes.                                           */
/* -------------------------------------------------------------------- */
    int nLevel = poFeature->GetFieldAsInteger( "Level" );
    int nGraphicGroup = poFeature->GetFieldAsInteger( "GraphicGroup" );
    int nColor = poFeature->GetFieldAsInteger( "ColorIndex" );
    int nWeight = poFeature->GetFieldAsInteger( "Weight" );
    int nStyle = poFeature->GetFieldAsInteger( "Style" );

    nLevel = MAX(0,MIN(63,nLevel));
    nColor = MAX(0,MIN(255,nGraphicGroup));
    nWeight = MAX(0,MIN(31,nWeight));
    nStyle = MAX(0,MIN(7,nStyle));

    DGNUpdateElemCore( hDGN, papsGroup[0], nLevel, nGraphicGroup, nColor, 
                       nWeight, nStyle );
    
/* -------------------------------------------------------------------- */
/*      Write to file.                                                  */
/* -------------------------------------------------------------------- */
    for( i = 0; papsGroup[i] != NULL; i++ )
    {
        DGNWriteElement( hDGN, papsGroup[i] );

        if( i == 0 )
            poFeature->SetFID( papsGroup[i]->element_id );

        DGNFreeElement( hDGN, papsGroup[i] );
    }

    CPLFree( papsGroup );

    return OGRERR_NONE;
}