/******************************************************************************
 * $Id: ogrpgdatasource.cpp,v 1.1 2000/10/17 17:46:51 warmerda Exp $
 *
 * Project:  OpenGIS Simple Features Reference Implementation
 * Purpose:  Implements OGRPGDataSource class.
 * Author:   Frank Warmerdam, warmerda@home.com
 *
 ******************************************************************************
 * Copyright (c) 2000, 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.
 ******************************************************************************
 *
 * $Log: ogrpgdatasource.cpp,v $
 * Revision 1.1  2000/10/17 17:46:51  warmerda
 * New
 *
 */

#include "ogr_pg.h"
#include "cpl_conv.h"
#include "cpl_string.h"

static void OGRPGNoticeProcessor( void *arg, const char * pszMessage );

/************************************************************************/
/*                         OGRPGDataSource()                         */
/************************************************************************/

OGRPGDataSource::OGRPGDataSource()

{
    pszName = NULL;
    papoLayers = NULL;
    nLayers = 0;
    hPGConn = NULL;
}

/************************************************************************/
/*                        ~OGRPGDataSource()                         */
/************************************************************************/

OGRPGDataSource::~OGRPGDataSource()

{
    CPLFree( pszName );

    for( int i = 0; i < nLayers; i++ )
        delete papoLayers[i];
    
    CPLFree( papoLayers );

    if( hPGConn != NULL )
        PQfinish( hPGConn );
}

/************************************************************************/
/*                                Open()                                */
/************************************************************************/

int OGRPGDataSource::Open( const char * pszNewName, int bUpdate,
                              int bTestOpen )

{
    CPLAssert( nLayers == 0 );

/* -------------------------------------------------------------------- */
/*      Verify postgresql prefix.                                       */
/* -------------------------------------------------------------------- */
    if( !EQUALN(pszNewName,"PG:",3) )
    {
        if( !bTestOpen )
            CPLError( CE_Failure, CPLE_AppDefined, 
                      "%s does not conform to PostgreSQL naming convention,"
                      " PG:*\n" );
        return FALSE;
    }
    
/* -------------------------------------------------------------------- */
/*      Try to establish connection.                                    */
/* -------------------------------------------------------------------- */
    hPGConn = PQconnectdb( pszNewName + 3 );
    if( hPGConn == NULL || PQstatus(hPGConn) == CONNECTION_BAD )
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "PGconnectcb failed.\n%s", 
                  PQerrorMessage(hPGConn) );
        PQfinish(hPGConn);
        hPGConn = NULL;
        return FALSE;
    }

    pszName = CPLStrdup( pszNewName );
    
    bDSUpdate = bUpdate;

/* -------------------------------------------------------------------- */
/*      Install a notice processor.                                     */
/* -------------------------------------------------------------------- */
    PQsetNoticeProcessor( hPGConn, OGRPGNoticeProcessor, this );

/* -------------------------------------------------------------------- */
/*      Get a list of available tables.                                 */
/* -------------------------------------------------------------------- */
    PGresult            *hResult;
    
    hResult = PQexec(hPGConn, "BEGIN");

    if( hResult && PQresultStatus(hResult) == PGRES_COMMAND_OK )
    {
        PQclear( hResult );

        hResult = PQexec(hPGConn, 
                         "DECLARE mycursor CURSOR for "
                         "SELECT relname FROM pg_class "
                         "WHERE relkind = 'r' AND relname !~ '^pg_'" );
    }

    if( hResult && PQresultStatus(hResult) == PGRES_COMMAND_OK )
    {
        PQclear( hResult );
        hResult = PQexec(hPGConn, "FETCH ALL in mycursor" );
    }

    if( !hResult || PQresultStatus(hResult) != PGRES_TUPLES_OK )
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "%s", PQerrorMessage(hPGConn) );
        return FALSE;
    }

/* -------------------------------------------------------------------- */
/*      Parse the returned table list                                   */
/* -------------------------------------------------------------------- */
    char	**papszTableNames=NULL;
    int	          iRecord;

    for( iRecord = 0; iRecord < PQntuples(hResult); iRecord++ )
    {
        papszTableNames = CSLAddString(papszTableNames, 
                                       PQgetvalue(hResult, iRecord, 0));
    }

/* -------------------------------------------------------------------- */
/*      Cleanup                                                         */
/* -------------------------------------------------------------------- */
    PQclear( hResult );

    hResult = PQexec(hPGConn, "CLOSE mycursor");
    PQclear( hResult );

    hResult = PQexec(hPGConn, "COMMIT");
    PQclear( hResult );

/* -------------------------------------------------------------------- */
/*      Get the schema of the available tables.                         */
/* -------------------------------------------------------------------- */
    for( iRecord = 0; 
         papszTableNames != NULL && papszTableNames[iRecord] != NULL;
         iRecord++ )
    {
        OpenTable( papszTableNames[iRecord], bUpdate, FALSE );
    }

    CSLDestroy( papszTableNames );
    
    return nLayers > 0 || bUpdate;
}

/************************************************************************/
/*                             OpenTable()                              */
/************************************************************************/

int OGRPGDataSource::OpenTable( const char *pszNewName, int bUpdate,
                                int bTestOpen )

{
/* -------------------------------------------------------------------- */
/*      Create the layer object.                                        */
/* -------------------------------------------------------------------- */
    OGRPGLayer	*poLayer;

    poLayer = new OGRPGLayer( this, pszNewName, bUpdate );

/* -------------------------------------------------------------------- */
/*      Add layer to data source layer list.                            */
/* -------------------------------------------------------------------- */
    papoLayers = (OGRPGLayer **)
        CPLRealloc( papoLayers,  sizeof(OGRPGLayer *) * (nLayers+1) );
    papoLayers[nLayers++] = poLayer;
    
    return TRUE;
}

/************************************************************************/
/*                            CreateLayer()                             */
/************************************************************************/

OGRLayer *
OGRPGDataSource::CreateLayer( const char * pszLayerName,
                              OGRSpatialReference *,
                              OGRwkbGeometryType eType,
                              char ** papszOptions )

{
    PGresult            *hResult;
    char		szCommand[1024];

    hResult = PQexec(hPGConn, "BEGIN");
    PQclear( hResult );

/* -------------------------------------------------------------------- */
/*      Create a table with just the FID and geometry fields.		*/
/* -------------------------------------------------------------------- */
    sprintf( szCommand, 
             "CREATE TABLE %s ( "
             "   ogc_fid SERIAL, "
             "   ogc_wkb bytea )",
             pszLayerName );
    hResult = PQexec(hPGConn, szCommand);
    if( PQresultStatus(hResult) != PGRES_COMMAND_OK )
    {
        CPLError( CE_Failure, CPLE_AppDefined, 
                  "%s\n%s", szCommand, PQerrorMessage(hPGConn) );

        PQclear( hResult );
        hResult = PQexec( hPGConn, "ROLLBACK" );
        PQclear( hResult );

        return NULL;
    }
    
    PQclear( hResult );

/* -------------------------------------------------------------------- */
/*      Eventually we should be adding this table to a table of         */
/*      "geometric layers", capturing the WKT projection, and           */
/*      perhaps some other housekeeping.                                */
/* -------------------------------------------------------------------- */
    
/* -------------------------------------------------------------------- */
/*      Complete, and commit the transaction.                           */
/* -------------------------------------------------------------------- */
    hResult = PQexec(hPGConn, "COMMIT");
    PQclear( hResult );

/* -------------------------------------------------------------------- */
/*      Create the layer object.                                        */
/* -------------------------------------------------------------------- */
    OGRPGLayer	*poLayer;

    poLayer = new OGRPGLayer( this, pszLayerName, TRUE );

/* -------------------------------------------------------------------- */
/*      Add layer to data source layer list.                            */
/* -------------------------------------------------------------------- */
    papoLayers = (OGRPGLayer **)
        CPLRealloc( papoLayers,  sizeof(OGRPGLayer *) * (nLayers+1) );
    
    papoLayers[nLayers++] = poLayer;

    return poLayer;
}

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

int OGRPGDataSource::TestCapability( const char * pszCap )

{
    if( EQUAL(pszCap,ODsCCreateLayer) )
        return TRUE;
    else
        return FALSE;
}

/************************************************************************/
/*                              GetLayer()                              */
/************************************************************************/

OGRLayer *OGRPGDataSource::GetLayer( int iLayer )

{
    if( iLayer < 0 || iLayer >= nLayers )
        return NULL;
    else
        return papoLayers[iLayer];
}

/************************************************************************/
/*                        OGRPGNoticeProcessor()                        */
/************************************************************************/

static void OGRPGNoticeProcessor( void *arg, const char * pszMessage )

{
    CPLDebug( "OGR_PG_NOTICE", "%s", pszMessage );
}
