/******************************************************************************
 * $Id: ogr_gensql.cpp 10646 2007-01-18 02:38:10Z warmerdam $
 *
 * Project:  OpenGIS Simple Features Reference Implementation
 * Purpose:  Implements OGRGenSQLResultsLayer.
 * Author:   Frank Warmerdam, warmerdam@pobox.com
 *
 ******************************************************************************
 * Copyright (c) 2002, Frank Warmerdam
 *
 * 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.
 ****************************************************************************/

#include "ogr_p.h"
#include "ogr_gensql.h"
#include "cpl_string.h"

CPL_CVSID("$Id: ogr_gensql.cpp 10646 2007-01-18 02:38:10Z warmerdam $");

/************************************************************************/
/*                       OGRGenSQLResultsLayer()                        */
/************************************************************************/

OGRGenSQLResultsLayer::OGRGenSQLResultsLayer( OGRDataSource *poSrcDS,
                                              void *pSelectInfo, 
                                              OGRGeometry *poSpatFilter )

{
    swq_select *psSelectInfo = (swq_select *) pSelectInfo;

    this->poSrcDS = poSrcDS;
    this->pSelectInfo = pSelectInfo;
    poDefn = NULL;
    poSummaryFeature = NULL;
    panFIDIndex = NULL;
    nIndexSize = 0;
    nNextIndexFID = 0;
    nExtraDSCount = 0;
    papoExtraDS = NULL;

/* -------------------------------------------------------------------- */
/*      Identify all the layers involved in the SELECT.                 */
/* -------------------------------------------------------------------- */
    int iTable;

    papoTableLayers = (OGRLayer **) 
        CPLCalloc( sizeof(OGRLayer *), psSelectInfo->table_count );

    for( iTable = 0; iTable < psSelectInfo->table_count; iTable++ )
    {
        swq_table_def *psTableDef = psSelectInfo->table_defs + iTable;
        OGRDataSource *poTableDS = poSrcDS;

        if( psTableDef->data_source != NULL )
        {
            OGRSFDriverRegistrar *poReg=OGRSFDriverRegistrar::GetRegistrar();

            poTableDS = 
                poReg->OpenShared( psTableDef->data_source, FALSE, NULL );
            if( poTableDS == NULL )
            {
                if( strlen(CPLGetLastErrorMsg()) == 0 )
                    CPLError( CE_Failure, CPLE_AppDefined, 
                              "Unable to open secondary datasource\n"
                              "`%s' required by JOIN.",
                              psTableDef->data_source );
                return;
            }

            papoExtraDS = (OGRDataSource **)
                CPLRealloc( papoExtraDS, sizeof(void*) * ++nExtraDSCount );

            papoExtraDS[nExtraDSCount-1] = poTableDS;
        }

        papoTableLayers[iTable] = 
            poTableDS->GetLayerByName( psTableDef->table_name );
        
        CPLAssert( papoTableLayers[iTable] != NULL );

        if( papoTableLayers[iTable] == NULL )
            return;
    }
    
    poSrcLayer = papoTableLayers[0];

/* -------------------------------------------------------------------- */
/*      Now that we have poSrcLayer, we can install a spatial filter    */
/*      if there is one.                                                */
/* -------------------------------------------------------------------- */
    if( poSpatFilter != NULL )
        SetSpatialFilter( poSpatFilter );

/* -------------------------------------------------------------------- */
/*      Prepare a feature definition based on the query.                */
/* -------------------------------------------------------------------- */
    OGRFeatureDefn *poSrcDefn = poSrcLayer->GetLayerDefn();

    poDefn = new OGRFeatureDefn( psSelectInfo->table_defs[0].table_alias );
    poDefn->Reference();

    iFIDFieldIndex = poSrcDefn->GetFieldCount();

    for( int iField = 0; iField < psSelectInfo->result_columns; iField++ )
    {
        swq_col_def *psColDef = psSelectInfo->column_defs + iField;
        OGRFieldDefn oFDefn( psColDef->field_name, OFTInteger );
        OGRFieldDefn *poSrcFDefn = NULL;
        OGRFeatureDefn *poLayerDefn = 
            papoTableLayers[psColDef->table_index]->GetLayerDefn();

        if( psColDef->field_index > -1 
            && psColDef->field_index < poLayerDefn->GetFieldCount() )
            poSrcFDefn = poLayerDefn->GetFieldDefn(psColDef->field_index);

        if( psColDef->col_func_name != NULL )
        {
            oFDefn.SetName( CPLSPrintf( "%s_%s",psColDef->col_func_name,
                                        psColDef->field_name) );
        }

        if( psColDef->col_func == SWQCF_COUNT )
            oFDefn.SetType( OFTInteger );
        else if( poSrcFDefn != NULL )
        {
            oFDefn.SetType( poSrcFDefn->GetType() );
            oFDefn.SetWidth( poSrcFDefn->GetWidth() );
            oFDefn.SetPrecision( poSrcFDefn->GetPrecision() );
        }
        else if ( psColDef->field_index >= iFIDFieldIndex )
        {
            switch ( SpecialFieldTypes[psColDef->field_index-iFIDFieldIndex] )
            {
              case SWQ_INTEGER:
                oFDefn.SetType( OFTInteger );
                break;
              case SWQ_FLOAT:
                oFDefn.SetType( OFTReal );
                break;
              default:
                oFDefn.SetType( OFTString );
                break;
            }
        }

        poDefn->AddFieldDefn( &oFDefn );
    }

    poDefn->SetGeomType( poSrcLayer->GetLayerDefn()->GetGeomType() );

/* -------------------------------------------------------------------- */
/*      If an ORDER BY is in effect, apply it now.                      */
/* -------------------------------------------------------------------- */
    if( psSelectInfo->order_specs > 0 
        && psSelectInfo->query_mode == SWQM_RECORDSET )
        CreateOrderByIndex();

    ResetReading();
}

/************************************************************************/
/*                       ~OGRGenSQLResultsLayer()                       */
/************************************************************************/

OGRGenSQLResultsLayer::~OGRGenSQLResultsLayer()

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

    ClearFilters();

/* -------------------------------------------------------------------- */
/*      Free various datastructures.                                    */
/* -------------------------------------------------------------------- */
    CPLFree( papoTableLayers );
    papoTableLayers = NULL;
             
    if( panFIDIndex != NULL )
        CPLFree( panFIDIndex );

    if( poSummaryFeature )
        delete poSummaryFeature;

    if( pSelectInfo != NULL )
        swq_select_free( (swq_select *) pSelectInfo );

    if( poDefn != NULL )
    {
        poDefn->Release();
    }

/* -------------------------------------------------------------------- */
/*      Release any additional datasources being used in joins.         */
/* -------------------------------------------------------------------- */
    OGRSFDriverRegistrar *poReg=OGRSFDriverRegistrar::GetRegistrar();

    for( int iEDS = 0; iEDS < nExtraDSCount; iEDS++ )
        poReg->ReleaseDataSource( papoExtraDS[iEDS] );

    CPLFree( papoExtraDS );
}

/************************************************************************/
/*                            ClearFilters()                            */
/*                                                                      */
/*      Clear up all filters currently in place on the target layer,    */
/*      and joined layers.  We try not to leave them installed          */
/*      except when actively fetching features.                         */
/************************************************************************/

void OGRGenSQLResultsLayer::ClearFilters()

{
/* -------------------------------------------------------------------- */
/*      Clear any filters installed on the target layer.                */
/* -------------------------------------------------------------------- */
    if( poSrcLayer != NULL )
    {
        poSrcLayer->SetAttributeFilter( "" );
        poSrcLayer->SetSpatialFilter( NULL );
    }

/* -------------------------------------------------------------------- */
/*      Clear any attribute filter installed on the joined layers.      */
/* -------------------------------------------------------------------- */
    swq_select *psSelectInfo = (swq_select *) pSelectInfo;
    int iJoin;

    if( psSelectInfo != NULL )
    {
        for( iJoin = 0; iJoin < psSelectInfo->join_count; iJoin++ )
        {
            swq_join_def *psJoinInfo = psSelectInfo->join_defs + iJoin;
            OGRLayer *poJoinLayer = 
                papoTableLayers[psJoinInfo->secondary_table];
            
            poJoinLayer->SetAttributeFilter( "" );
        }
    }
}

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

void OGRGenSQLResultsLayer::ResetReading() 

{
    swq_select *psSelectInfo = (swq_select *) pSelectInfo;

    if( psSelectInfo->query_mode == SWQM_RECORDSET )
    {
        poSrcLayer->SetAttributeFilter( psSelectInfo->whole_where_clause );
        
        poSrcLayer->SetSpatialFilter( m_poFilterGeom );
        
        poSrcLayer->ResetReading();
    }

    nNextIndexFID = 0;
}

/************************************************************************/
/*                           SetNextByIndex()                           */
/*                                                                      */
/*      If we already have an FID list, we can easily resposition       */
/*      ourselves in it.                                                */
/************************************************************************/

OGRErr OGRGenSQLResultsLayer::SetNextByIndex( long nIndex )

{
    swq_select *psSelectInfo = (swq_select *) pSelectInfo;

    if( psSelectInfo->query_mode == SWQM_SUMMARY_RECORD 
        || psSelectInfo->query_mode == SWQM_DISTINCT_LIST 
        || panFIDIndex != NULL )
    {
        nNextIndexFID = nIndex;
        return OGRERR_NONE;
    }
    else
    {
        return poSrcLayer->SetNextByIndex( nIndex );
    }
}

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

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

{
    swq_select *psSelectInfo = (swq_select *) pSelectInfo;

    if( psSelectInfo->query_mode == SWQM_RECORDSET )
        return poSrcLayer->GetExtent( psExtent, bForce );
    else
        return OGRERR_FAILURE;
}

/************************************************************************/
/*                           GetSpatialRef()                            */
/************************************************************************/

OGRSpatialReference *OGRGenSQLResultsLayer::GetSpatialRef() 

{
    swq_select *psSelectInfo = (swq_select *) pSelectInfo;

    if( psSelectInfo->query_mode != SWQM_RECORDSET )
        return NULL;
    else
        return poSrcLayer->GetSpatialRef();
}

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

int OGRGenSQLResultsLayer::GetFeatureCount( int bForce )

{
    swq_select *psSelectInfo = (swq_select *) pSelectInfo;

    if( psSelectInfo->query_mode != SWQM_RECORDSET )
        return 1;
    else if( m_poAttrQuery == NULL )
        return poSrcLayer->GetFeatureCount( bForce );
    else
        return OGRLayer::GetFeatureCount( bForce );