/******************************************************************************
 * $Id$
 *
 * Project:  GDAL/OGR Geography Network support (Geographic Network Model)
 * Purpose:  GNM network class.
 * Authors:  Mikhail Gusev (gusevmihs at gmail dot com)
 *           Dmitry Baryshnikov, polimax@mail.ru
 *
 ******************************************************************************
 * Copyright (c) 2014, Mikhail Gusev
 * Copyright (c) 2014-2015, NextGIS <info@nextgis.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.
 ****************************************************************************/

#include "gnm_api.h"
#include "ogrsf_frmts.h"

#include <set>

GNMGenericNetwork::GNMGenericNetwork() :
    GNMNetwork(),
    m_nVersion(0),
    m_nGID(0),
    m_nVirtualConnectionGID(-1),
    m_poMetadataLayer(NULL),
    m_poGraphLayer(NULL),
    m_poFeaturesLayer(NULL),
    m_poLayerDriver(NULL),
    m_bIsRulesChanged(false),
    m_bIsGraphLoaded(false)
{
}

GNMGenericNetwork::~GNMGenericNetwork()
{
    for(size_t i = 0; i < m_apoLayers.size(); i++)
        delete m_apoLayers[i];
}

int GNMGenericNetwork::GetLayerCount()
{
    return (int)m_apoLayers.size();
}

OGRLayer *GNMGenericNetwork::GetLayer(int nIndex)
{
    if(nIndex < 0 || nIndex >= (int)m_apoLayers.size())
        return NULL;
    return m_apoLayers[nIndex];
}

OGRErr GNMGenericNetwork::DeleteLayer(int nIndex)
{
    if(nIndex < 0 || nIndex >= (int)m_apoLayers.size())
        return OGRERR_FAILURE;

    const char* pszLayerName = m_apoLayers[nIndex]->GetName();
    OGRFeature *poFeature;

    std::set<GNMGFID> anGFIDs;
    std::set<GNMGFID>::iterator it;
    // remove layer GFID's from Features layer

    m_poFeaturesLayer->ResetReading();
    while ((poFeature = m_poFeaturesLayer->GetNextFeature()) != NULL)
    {
        const char *pFeatureClass = poFeature->GetFieldAsString(
                    GNM_SYSFIELD_LAYERNAME);

        if(EQUAL(pFeatureClass, pszLayerName))
        {
            anGFIDs.insert(poFeature->GetFieldAsGNMGFID(GNM_SYSFIELD_GFID));
            CPL_IGNORE_RET_VAL(m_poFeaturesLayer->DeleteFeature(poFeature->GetFID()));
        }
        OGRFeature::DestroyFeature(poFeature);
    }

    // remove GFID's from graph layer

    m_poGraphLayer->ResetReading();
    while ((poFeature = m_poGraphLayer->GetNextFeature()) != NULL)
    {
        GNMGFID nGFID = poFeature->GetFieldAsGNMGFID(GNM_SYSFIELD_SOURCE);
        it = anGFIDs.find(nGFID);
        if( it != anGFIDs.end())
        {
            CPL_IGNORE_RET_VAL(m_poGraphLayer->DeleteFeature(poFeature->GetFID()));
            OGRFeature::DestroyFeature(poFeature);
            continue;
        }

        nGFID = poFeature->GetFieldAsGNMGFID(GNM_SYSFIELD_TARGET);
        it = anGFIDs.find(nGFID);
        if( it != anGFIDs.end())
        {
            CPL_IGNORE_RET_VAL(m_poGraphLayer->DeleteFeature(poFeature->GetFID()));
            OGRFeature::DestroyFeature(poFeature);
            continue;
        }

        nGFID = poFeature->GetFieldAsGNMGFID(GNM_SYSFIELD_CONNECTOR);
        it = anGFIDs.find(nGFID);
        if( it != anGFIDs.end())
        {
            CPL_IGNORE_RET_VAL(m_poGraphLayer->DeleteFeature(poFeature->GetFID()));
            OGRFeature::DestroyFeature(poFeature);
            continue;
        }

        OGRFeature::DestroyFeature(poFeature);
    }

    // remove connected rules
    for(size_t i = m_asRules.size(); i > 0; --i)
    {
        if(EQUAL(m_asRules[i - 1].GetSourceLayerName(), pszLayerName))
        {
            m_asRules.erase(m_asRules.begin() + i - 1);
            m_bIsRulesChanged = true;
        }
        else if(EQUAL(m_asRules[i - 1].GetTargetLayerName(), pszLayerName))
        {
            m_asRules.erase(m_asRules.begin() + i - 1);
            m_bIsRulesChanged = true;
        }
        else if(EQUAL(m_asRules[i - 1].GetConnectorLayerName(), pszLayerName))
        {
            m_asRules.erase(m_asRules.begin() + i - 1);
            m_bIsRulesChanged = true;
        }
    }

    delete m_apoLayers[nIndex];
    // remove from array
    m_apoLayers.erase (m_apoLayers.begin() + nIndex);
    return OGRERR_NONE;
}

CPLErr GNMGenericNetwork::Delete()
{
    CPLErr eResult = DeleteNetworkLayers();
    if(eResult != CE_None)
        return eResult;
    eResult = DeleteMetadataLayer();
    if(eResult != CE_None)
        return eResult;
    eResult = DeleteGraphLayer();
    if(eResult != CE_None)
        return eResult;

    return DeleteFeaturesLayer();
}

int GNMGenericNetwork::GetVersion() const
{
    return m_nVersion;
}

GIntBig GNMGenericNetwork::GetNewGlobalFID()
{
    return m_nGID++;
}

CPLString GNMGenericNetwork::GetAlgorithmName(GNMDirection eAlgorithm,
                                              bool bShortName)
{
    switch(eAlgorithm)
    {
    case GATDijkstraShortestPath:
        if(bShortName)
            return CPLString("Dijkstra");
        else
            return CPLString("Dijkstra shortest path");
    case GATKShortestPath:
        if(bShortName)
            return CPLString("Yens");
        else
            return CPLString("Yens shortest paths");
    case GATConnectedComponents:
        if(bShortName)
            return CPLString("Connected");
        else
            return CPLString("Connected components");
    }

    return CPLString("Invalid");
}

CPLErr GNMGenericNetwork::AddFeatureGlobalFID(GNMGFID nFID,
                                              const char *pszLayerName)
{
    OGRFeature *poFeature = OGRFeature::CreateFeature(
                m_poFeaturesLayer->GetLayerDefn() );
    poFeature->SetField( GNM_SYSFIELD_GFID, nFID );
    poFeature->SetField( GNM_SYSFIELD_LAYERNAME, pszLayerName );

    if( m_poFeaturesLayer->CreateFeature( poFeature ) != OGRERR_NONE )
    {
        OGRFeature::DestroyFeature( poFeature );
        CPLError( CE_Failure, CPLE_AppDefined, "Failed to create feature." );
        return CE_Failure;
    }

    OGRFeature::DestroyFeature( poFeature );

    return CE_None;
}

CPLErr GNMGenericNetwork::ConnectFeatures(GNMGFID nSrcGFID, GNMGFID nTgtGFID,
                                          GNMGFID nConGFID, double dfCost,
                                          double dfInvCost, GNMDirection eDir)
{
    if(!m_bIsGraphLoaded && LoadGraph() != CE_None)
    {
        return CE_Failure;
    }

    OGRFeature *poFeature = FindConnection(nSrcGFID, nTgtGFID, nConGFID);
    if(poFeature != NULL)
    {
        OGRFeature::DestroyFeature( poFeature );
        CPLError( CE_Failure, CPLE_AppDefined, "The connection already created" );
        return CE_Failure;
    }

    if(m_asRules.empty())
    {
        CPLError( CE_Failure, CPLE_AppDefined, "The connection forbidden" );
        return CE_Failure;
    }
    else
    {
        CPLString soSrcLayerName = m_moFeatureFIDMap[nSrcGFID];
        CPLString soTgtLayerName = m_moFeatureFIDMap[nTgtGFID];
        CPLString soConnLayerName = m_moFeatureFIDMap[nConGFID];
        for(size_t i = 0; i < m_asRules.size(); ++i)
        {
            if(!m_asRules[i].CanConnect(soSrcLayerName, soTgtLayerName,
                                        soConnLayerName))
            {
                CPLError( CE_Failure, CPLE_AppDefined, "The connection forbidden" );
                return CE_Failure;
            }
        }
    }

    // we support both vertices and edge to be virtual
    if(nConGFID == -1)
       nConGFID = GetNewVirtualFID();
    if(nSrcGFID == -1)
       nSrcGFID = GetNewVirtualFID();
    if(nTgtGFID == -1)
       nTgtGFID = GetNewVirtualFID();

    poFeature = OGRFeature::CreateFeature( m_poGraphLayer->GetLayerDefn() );
    poFeature->SetField( GNM_SYSFIELD_SOURCE, nSrcGFID );
    poFeature->SetField( GNM_SYSFIELD_TARGET, nTgtGFID );
    poFeature->SetField( GNM_SYSFIELD_CONNECTOR, nConGFID );
    poFeature->SetField( GNM_SYSFIELD_COST, dfCost );
    poFeature->SetField( GNM_SYSFIELD_INVCOST, dfInvCost );
    poFeature->SetField( GNM_SYSFIELD_DIRECTION, eDir );
    poFeature->SetField( GNM_SYSFIELD_BLOCKED, GNM_BLOCK_NONE );

    if( m_poGraphLayer->CreateFeature( poFeature ) != OGRERR_NONE )
    {
        OGRFeature::DestroyFeature( poFeature );
        CPLError( CE_Failure, CPLE_AppDefined, "Failed to create feature." );
        return CE_Failure;
    }

    OGRFeature::DestroyFeature( poFeature );

    // update graph

    m_oGraph.AddEdge(nConGFID, nSrcGFID, nTgtGFID, eDir == GNM_EDGE_DIR_BOTH,
                     dfCost, dfInvCost);

    return CE_None;
}

CPLErr GNMGenericNetwork::DisconnectFeatures(GNMGFID nSrcGFID, GNMGFID nTgtGFID,
                                             GNMGFID nConGFID)
{
    if(!m_bIsGraphLoaded && LoadGraph() != CE_None)
    {
        return CE_Failure;
    }

    OGRFeature *poFeature = FindConnection(nSrcGFID, nTgtGFID, nConGFID);
    if (poFeature == NULL)
    {
        CPLError( CE_Failure, CPLE_AppDefined, "The connection not exist" );
        return CE_Failure;
    }

    if (m_poGraphLayer->DeleteFeature(poFeature->GetFID()) != OGRERR_NONE)
    {
        OGRFeature::DestroyFeature(poFeature);
        return CE_Failure;
    }

    OGRFeature::DestroyFeature(poFeature);

    // update graph

    m_oGraph.DeleteEdge(nConGFID);

    return CE_None;
}

CPLErr GNMGenericNetwork::DisconnectFeaturesWithId(GNMGFID nFID)
{
    if(!m_bIsGraphLoaded && LoadGraph() != CE_None)
    {
        return CE_Failure;
    }

    CPLString soFilter;
    soFilter.Printf("%s = " GNMGFIDFormat " or %s = " GNMGFIDFormat " or %s = " GNMGFIDFormat,
                    GNM_SYSFIELD_SOURCE, nFID,
                    GNM_SYSFIELD_TARGET, nFID,
                    GNM_SYSFIELD_CONNECTOR, nFID);

    CPLDebug("GNM", "Set attribute filter: %s", soFilter.c_str());

    m_poGraphLayer->SetAttributeFilter(soFilter);
    m_poGraphLayer->ResetReading();
    OGRFeature* poFeature;
    while ((poFeature = m_poGraphLayer->GetNextFeature()) != NULL)
    {
        if(m_poGraphLayer->DeleteFeature(poFeature->GetFID()) != CE_None)
        {
            OGRFeature::DestroyFeature( poFeature );
            CPLError( CE_Failure, CPLE_AppDefined,
                                       "Failed to remove feature connection." );
            return CE_Failure;
        }
        OGRFeature::DestroyFeature( poFeature );
    }

    m_poGraphLayer->SetAttributeFilter(NULL);

    m_oGraph.DeleteEdge(nFID);
    m_oGraph.DeleteVertex(nFID);

    return CE_None;
}

CPLErr GNMGenericNetwork::ReconnectFeatures(GNMGFID nSrcGFID, GNMGFID nTgtGFID,
                                            GNMGFID nConGFID, double dfCost,
                                            double dfInvCost, GNMDirection eDir)
{
    if(!m_bIsGraphLoaded && LoadGraph() != CE_None)
    {
        return CE_Failure;
    }

    OGRFeature *poFeature = FindConnection(nSrcGFID, nTgtGFID, nConGFID);
    if (poFeature == NULL)
    {
        CPLError( CE_Failure, CPLE_AppDefined, "The connection not exist" );
        return CE_Failure;
    }

    poFeature->SetField( GNM_SYSFIELD_COST, dfCost );
    poFeature->SetField( GNM_SYSFIELD_INVCOST, dfInvCost );
    poFeature->SetField( GNM_SYSFIELD_DIRECTION, eDir );

    if( m_poGraphLayer->SetFeature( poFeature ) != OGRERR_NONE )
    {
        OGRFeature::DestroyFeature( poFeature );
        CPLError( CE_Failure, CPLE_AppDefined, "Failed to update feature." );
        return CE_Failure;
    }

    OGRFeature::DestroyFeature( poFeature );

    // update graph

    m_oGraph.ChangeEdge(nConGFID, dfCost, dfInvCost);

    return CE_None;
}

CPLErr GNMGenericNetwork::DisconnectAll()
{
    if(!m_bIsGraphLoaded && LoadGraph() != CE_None)
    {
        return CE_Failure;
    }
    // delete everything from m_pGraphLayer

    OGRFeature *poFeature;
    m_poGraphLayer->ResetReading();
    while ((poFeature = m_poGraphLayer->GetNextFeature()) != NULL)
    {
        CPL_IGNORE_RET_VAL(m_poGraphLayer->DeleteFeature(poFeature->GetFID()));
        OGRFeature::DestroyFeature( poFeature );
    }

    m_oGraph.Clear();

    return CE_None;
}

OGRFeature *GNMGenericNetwork::GetFeatureByGlobalFID(GNMGFID nFID)
{
    CPLString soLayerName = m_moFeatureFIDMap[nFID];
    for(size_t i = 0; i < m_apoLayers.size(); ++i)
    {
        if(EQUAL(soLayerName, m_apoLayers[i]->GetName()))
            return m_apoLayers[i]->GetFeature(nFID);
    }
    return NULL;
}

CPLErr GNMGenericNetwork::CreateRule(const char *pszRuleStr)
{
    CPLDebug("GNM", "Try to create rule '%s'", pszRuleStr);
    GNMRule oRule(pszRuleStr);
    if(!oRule.IsValid())
    {
        return CE_Failure;
    }

    if(!oRule.IsAcceptAny())
    {
        bool bSrcExist = false;
        bool bTgtExist = false;
        bool bConnExist = false;
        // check layers exist
        for(size_t i = 0; i < m_apoLayers.size(); ++i)
        {
            if(EQUAL(oRule.GetSourceLayerName(), m_apoLayers[i]->GetName()))
            {
                bSrcExist = true;
            }
            else if(EQUAL(oRule.GetTargetLayerName(), m_apoLayers[i]->GetName()))
            {
                bTgtExist = true;
            }
            else if(EQUAL(oRule.GetConnectorLayerName(), m_apoLayers[i]->GetName()))
            {
                bConnExist = true;
            }
        }

        if(!bSrcExist || !bTgtExist)
        {
            CPLError( CE_Failure, CPLE_IllegalArg, "Layers '%s' or '%s' not exist",
                      oRule.GetSourceLayerName().c_str(),
                      oRule.GetTargetLayerName().c_str());
            return CE_Failure;
        }

        if(!bConnExist && !oRule.GetConnectorLayerName().empty())
        {
            CPLError( CE_Failure, CPLE_IllegalArg, "Connector layer '%s' not exist",
                      oRule.GetConnectorLayerName().c_str());
            return CE_Failure;
        }
    }

    m_asRules.push_back(oRule);
    m_bIsRulesChanged = true;

    return CE_None;
}

CPLErr GNMGenericNetwork::DeleteAllRules()
{
    CPLString soFilter;
    soFilter.Printf("%s LIKE '%s%%'", GNM_SYSFIELD_PARAMNAME, GNM_MD_RULE);
    m_poMetadataLayer->SetAttributeFilter(soFilter);

    m_poMetadataLayer->ResetReading();
    OGRFeature *poFeature;
    std::vector<GIntBig> aFIDs;
    while((poFeature = m_poMetadataLayer->GetNextFeature()) != NULL)
    {
        aFIDs.push_back(poFeature->GetFID());
        OGRFeature::DestroyFeature(poFeature);
    }

    m_poMetadataLayer->SetAttributeFilter(NULL);
    for(size_t i = 0; i < aFIDs.size(); ++i)
    {
        CPL_IGNORE_RET_VAL(m_poMetadataLayer->DeleteFeature(aFIDs[i]));
    }

    return CE_None;
}

CPLErr GNMGenericNetwork::DeleteRule(const char *pszRuleStr)
{
    for(size_t i = 0; i < m_asRules.size(); ++i)
    {
        if(EQUAL(pszRuleStr, m_asRules[i]))
        {
            m_asRules.erase(m_asRules.begin() + i);
            m_bIsRulesChanged = true;
            return CE_None;
        }
    }

    return CE_Failure;
}

char **GNMGenericNetwork::GetRules() const
{
    char** papszRules = NULL;
    for(size_t i = 0; i < m_asRules.size(); ++i)
    {
        papszRules = CSLAddString(papszRules, m_asRules[i]);
    }
    return papszRules;
}

CPLErr GNMGenericNetwork::ConnectPointsByLines(char **papszLayerList,
                                               double dfTolerance, double dfCost,
                                               double dfInvCost, GNMDirection eDir)
{
    if( CSLCount(papszLayerList) < 2 )
    {
        CPLError( CE_Failure, CPLE_IllegalArg, "Minimum 2 layers needed to connect" );
        return CE_Failure;
    }

    std::vector<OGRLayer*> paLineLayers;
    std::vector<OGRLayer*> paPointLayers;
    int eType;
    int iLayer;
    OGRLayer* poLayer;

    for(iLayer = 0; papszLayerList[iLayer] != NULL; ++iLayer)
    {
        poLayer = GetLayerByName(papszLayerList[iLayer]);
        if(NULL == poLayer)
            continue;

        eType = wkbFlatten(poLayer->GetGeomType());
        if(eType == wkbLineString || eType == wkbMultiLineString)
        {
            paLineLayers.push_back(poLayer);
        }
        else if(eType == wkbPoint)
        {
            paPointLayers.push_back(poLayer);
        }
    }

    if (paLineLayers.empty() || paPointLayers.empty() )
    {
        CPLError( CE_Failure, CPLE_IllegalArg, "Need at least one line (or "
                            "multiline) layer and one point layer to connect" );
        return CE_Failure;
    }

    // now walk through all lines and find nearest points for line start and end
    OGRFeature* poFeature;
    for(size_t i = 0; i < paLineLayers.size(); ++i)
    {
        poLayer = paLineLayers[i];
        eType = wkbFlatten(poLayer->GetGeomType());

        poLayer->ResetReading();
        while((poFeature = poLayer->GetNextFeature()) != NULL)
        {
            const OGRGeometry* poGeom = poFeature->GetGeometryRef();
            if(NULL != poGeom)
            {
                if(eType == wkbLineString)
                {
                    const OGRLineString* poLineString =
                                                  (const OGRLineString*) poGeom;
                    ConnectPointsByLine(poFeature->GetFID(), poLineString,
                                        paPointLayers, dfTolerance, dfCost,
                                        dfInvCost, eDir);
                }
                else if( eType == wkbMultiLineString)
                {
                    const OGRMultiLineString* poMultiLineString =
                                             (const OGRMultiLineString*) poGeom;
                    ConnectPointsByMultiline(poFeature->GetFID(), poMultiLineString,
                                             paPointLayers, dfTolerance, dfCost,
                                             dfInvCost, eDir);
                }
            }
            OGRFeature::DestroyFeature(poFeature);
        }
    }

    return CE_None;
}

CPLErr GNMGenericNetwork::ChangeBlockState(GNMGFID nFID, bool bIsBlock)
{
    if(!m_bIsGraphLoaded && LoadGraph() != CE_None)
    {
        return CE_Failure;
    }

    // change block state in layer
    OGRLayer* poLayer = GetLayerByName(m_moFeatureFIDMap[nFID]);
    if(NULL == poLayer)
    {
        CPLError( CE_Failure, CPLE_AppDefined, "Failed to get layer '%s'.",
                  m_moFeatureFIDMap[nFID].c_str() );
        return CE_Failure;
    }

    OGRFeature* poFeature = poLayer->GetFeature(nFID);
    if(NULL == poFeature)
    {
        CPLError( CE_Failure, CPLE_AppDefined, "Failed to get feature '"
                  GNMGFIDFormat"'.", nFID );
        return CE_Failure;
    }

    if(bIsBlock)
    {
        poFeature->SetField( GNM_SYSFIELD_BLOCKED, GNM_BLOCK_ALL );
    }
    else
    {
        poFeature->SetField( GNM_SYSFIELD_BLOCKED, GNM_BLOCK_NONE );
    }

    if( poLayer->SetFeature( poFeature ) != OGRERR_NONE )
    {
        OGRFeature::DestroyFeature( poFeature );
        CPLError( CE_Failure, CPLE_AppDefined, "Failed to update feature." );
        return CE_Failure;
    }

    OGRFeature::DestroyFeature( poFeature );

    GNMGFID nSrcFID, nTgtFID, nConFID;

    // change block state in graph layer
    m_poGraphLayer->ResetReading();
    while ((poFeature = m_poGraphLayer->GetNextFeature()) != NULL)
    {
        nSrcFID = poFeature->GetFieldAsGNMGFID(GNM_SYSFIELD_SOURCE);
        nTgtFID = poFeature->GetFieldAsGNMGFID(GNM_SYSFIELD_TARGET);
        nConFID = poFeature->GetFieldAsGNMGFID(GNM_SYSFIELD_CONNECTOR);
        int nBlockState = poFeature->GetFieldAsInteger(GNM_SYSFIELD_BLOCKED);

        if(bIsBlock)
        {
            if(nSrcFID == nFID)
                nBlockState |= GNM_BLOCK_SRC;
            else if(nTgtFID == nFID)
                nBlockState |= GNM_BLOCK_TGT;
            else if(nConFID == nFID)
                nBlockState |= GNM_BLOCK_CONN;

            poFeature->SetField( GNM_SYSFIELD_BLOCKED, nBlockState );
        }
        else
        {
            if(nSrcFID == nFID)
                nBlockState &= ~GNM_BLOCK_SRC;
            else if(nTgtFID == nFID)
                nBlockState &= ~GNM_BLOCK_TGT;
            else if(nConFID == nFID)
                nBlockState &= ~GNM_BLOCK_CONN;

            poFeature->SetField( GNM_SYSFIELD_BLOCKED, nBlockState );
        }

        if( m_poGraphLayer->SetFeature( poFeature ) != OGRERR_NONE )
        {
            OGRFeature::DestroyFeature( poFeature );
            CPLError( CE_Failure, CPLE_AppDefined, "Failed to update feature." );
            return CE_Failure;
        }

        OGRFeature::DestroyFeature( poFeature );
    }

    // change block state in graph
    m_oGraph.ChangeBlockState(nFID, bIsBlock);

    return CE_None;
}

CPLErr GNMGenericNetwork::ChangeAllBlockState(bool bIsBlock)
{
    if(!m_bIsGraphLoaded && LoadGraph() != CE_None)
    {
        return CE_Failure;
    }

    OGRFeature *poFeature;
    m_poGraphLayer->ResetReading();
    while ((poFeature = m_poGraphLayer->GetNextFeature()) != NULL)
    {
        if(bIsBlock)
        {
            poFeature->SetField( GNM_SYSFIELD_BLOCKED, GNM_BLOCK_ALL );
        }
        else
        {
            poFeature->SetField( GNM_SYSFIELD_BLOCKED, GNM_BLOCK_NONE );
        }

        if( m_poGraphLayer->SetFeature( poFeature ) != OGRERR_NONE )
        {
            OGRFeature::DestroyFeature( poFeature );
            CPLError( CE_Failure, CPLE_AppDefined, "Failed to update feature." );
            return CE_Failure;
        }

        OGRFeature::DestroyFeature( poFeature );
    }

    // change all network layers

    for(size_t i = 0; i < m_apoLayers.size(); ++i)
    {
        OGRLayer* poLayer = m_apoLayers[i];
        if(NULL == poLayer)
            continue;
        while ((poFeature = poLayer->GetNextFeature()) != NULL)
        {
            if(bIsBlock)
            {
                poFeature->SetField( GNM_SYSFIELD_BLOCKED, GNM_BLOCK_ALL );
            }
            else
            {
                poFeature->SetField( GNM_SYSFIELD_BLOCKED, GNM_BLOCK_NONE );
            }

            if( poLayer->SetFeature( poFeature ) != OGRERR_NONE )
            {
                OGRFeature::DestroyFeature( poFeature );
                CPLError( CE_Failure, CPLE_AppDefined, "Failed to update feature." );
                return CE_Failure;
            }

            OGRFeature::DestroyFeature( poFeature );
        }
    }

    m_oGraph.ChangeAllBlockState(bIsBlock);

    return CE_None;
}

OGRLayer *GNMGenericNetwork::GetPath(GNMGFID nStartFID, GNMGFID nEndFID,
                          GNMGraphAlgorithmType eAlgorithm, char **papszOptions)
{

    if(!m_bIsGraphLoaded && LoadGraph() != CE_None)
    {
        return NULL;
    }

    GDALDriver* poMEMDrv =
            OGRSFDriverRegistrar::GetRegistrar()->GetDriverByName("Memory");
    if (poMEMDrv == NULL)
    {
        CPLError(CE_Failure, CPLE_AppDefined, "Cannot load 'Memory' driver");
        return NULL;
    }

    GDALDataset* poMEMDS =
            poMEMDrv->Create("dummy_name", 0, 0, 0, GDT_Unknown, NULL);
    OGRSpatialReference oDstSpaRef(GetProjectionRef());
    OGRLayer* poMEMLayer = poMEMDS->CreateLayer(GetAlgorithmName(eAlgorithm,
                               true), &oDstSpaRef, wkbGeometryCollection, NULL);

    OGRGNMWrappedResultLayer* poResLayer =
                              new OGRGNMWrappedResultLayer(poMEMDS, poMEMLayer);

    bool bReturnEdges = CPL_TO_BOOL(CSLFetchBoolean(papszOptions, GNM_MD_FETCHEDGES, TRUE));
    bool bReturnVertices = CPL_TO_BOOL(CSLFetchBoolean(papszOptions, GNM_MD_FETCHVERTEX, TRUE));

    switch (eAlgorithm)
    {
    case GATDijkstraShortestPath:
        {
            GNMPATH path = m_oGraph.DijkstraShortestPath(nStartFID, nEndFID);

            // fill features in result layer
            FillResultLayer(poResLayer, path, 1, bReturnVertices, bReturnEdges);
        }
        break;
    case GATKShortestPath:
        {
            int nK = atoi(CSLFetchNameValueDef(papszOptions, GNM_MD_NUM_PATHS,
                                               "1"));

            CPLDebug("GNM", "Search %d path(s)", nK);

            std::vector<GNMPATH> paths = m_oGraph.KShortestPaths(nStartFID,
                                                                 nEndFID, nK);

            // fill features in result layer
            for(size_t i = 0; i < paths.size(); ++i)
            {
                FillResultLayer(poResLayer, paths[i], static_cast<int>(i + 1), bReturnVertices,
                                bReturnEdges);
            }
        }
        break;
    case GATConnectedComponents:
        {
            GNMVECTOR anEmitters;
            if(NULL != papszOptions)
            {
                char** papszEmitter = CSLFetchNameValueMultiple(papszOptions, GNM_MD_EMITTER);
                for(int i = 0; papszEmitter[i] != NULL; ++i)
                {
                    GNMGFID nEmitter = atol(papszEmitter[i]);
                    anEmitters.push_back(nEmitter);
                }
                CSLDestroy(papszEmitter);
            }

            if(nStartFID != -1)
            {
                anEmitters.push_back(nStartFID);
            }

            if(nStartFID != -1)
            {
                anEmitters.push_back(nEndFID);
            }

            GNMPATH path = m_oGraph.ConnectedComponents(anEmitters);

            // fill features in result layer
            FillResultLayer(poResLayer, path, 1, bReturnVertices, bReturnEdges);
        }
        break;
    }

    return poResLayer;
}

void GNMGenericNetwork::ConnectPointsByMultiline(GIntBig nFID,
                                    const OGRMultiLineString* poMultiLineString,
                                    const std::vector<OGRLayer*>& paPointLayers,
                                    double dfTolerance, double dfCost,
                                    double dfInvCost, GNMDirection eDir)
{
    VALIDATE_POINTER0(poMultiLineString,
                                 "GNMGenericNetwork::ConnectPointsByMultiline");
    for(int i = 0; i < poMultiLineString->getNumGeometries(); ++i)
    {
        const OGRLineString* poLinestring =
                (OGRLineString*)poMultiLineString->getGeometryRef(i);
        ConnectPointsByLine(nFID, poLinestring, paPointLayers, dfTolerance,
                            dfCost, dfInvCost, eDir);
    }
}

void GNMGenericNetwork::ConnectPointsByLine(GIntBig nFID,
                                    const OGRLineString* poLineString,
                                    const std::vector<OGRLayer*>& paPointLayers,
                                    double dfTolerance, double dfCost,
                                    double dfInvCost, GNMDirection eDir)
{
    VALIDATE_POINTER0(poLineString, "GNMGenericNetwork::ConnectPointsByLine");
    OGRPoint oStartPoint, oEndPoint;
    poLineString->StartPoint(&oStartPoint);
    poLineString->EndPoint(&oEndPoint);
    double dfHalfTolerance = dfTolerance / 2;

    GNMGFID nSrcFID = FindNearestPoint(&oStartPoint, paPointLayers, dfHalfTolerance);
    GNMGFID nTgtFID = FindNearestPoint(&oEndPoint, paPointLayers, dfHalfTolerance);

    if(nSrcFID == -1 || nTgtFID == -1)
        return;

    // connect nSrcFID with nTgtFID via nFID
    ConnectFeatures(nSrcFID, nTgtFID, (GNMGFID)nFID, dfCost, dfInvCost, eDir);
}

GNMGFID GNMGenericNetwork::FindNearestPoint(const OGRPoint* poPoint,
                                    const std::vector<OGRLayer*>& paPointLayers,
                                    double dfTolerance)
{
    VALIDATE_POINTER1(poPoint, "GNMGenericNetwork::FindNearestPoint", -1);
    double dfMinX = poPoint->getX() - dfTolerance;
    double dfMinY = poPoint->getY() - dfTolerance;
    double dfMaxX = poPoint->getX() + dfTolerance;
    double dfMaxY = poPoint->getY() + dfTolerance;

    OGRFeature *poFeature;

    for(size_t i = 0; i < paPointLayers.size(); ++i)
    {
        OGRLayer *poLayer = paPointLayers[i];

        poLayer->SetSpatialFilterRect(dfMinX, dfMinY,
                                      dfMaxX, dfMaxY);
        poLayer->ResetReading();
        while((poFeature = poLayer->GetNextFeature()) != NULL)
        {
            GNMGFID nRetFID = poFeature->GetFieldAsGNMGFID(GNM_SYSFIELD_GFID);
            OGRFeature::DestroyFeature(poFeature);
            return nRetFID;
        }
    }

    return -1;
}

OGRFeature *GNMGenericNetwork::FindConnection(GNMGFID nSrcFID, GNMGFID nTgtFID,
                                              GNMGFID nConFID)
{

    CPLString soFilter;
    soFilter.Printf("%s = " GNMGFIDFormat " and %s = " GNMGFIDFormat " and %s = " GNMGFIDFormat,
                    GNM_SYSFIELD_SOURCE, nSrcFID,
                    GNM_SYSFIELD_TARGET, nTgtFID,
                    GNM_SYSFIELD_CONNECTOR, nConFID);

    CPLDebug("GNM", "Set attribute filter: %s", soFilter.c_str());

    m_poGraphLayer->SetAttributeFilter(soFilter);
    m_poGraphLayer->ResetReading();
    OGRFeature *f = m_poGraphLayer->GetNextFeature();
    m_poGraphLayer->SetAttributeFilter(NULL);
    return f;
}

void GNMGenericNetwork::SaveRules()
{
    if(!m_bIsRulesChanged)
        return;

    if(DeleteAllRules() != CE_None)
        return;

    OGRFeature *poFeature;
    for(int i = 0; i < (int)m_asRules.size(); ++i)
    {
        poFeature = OGRFeature::CreateFeature(m_poMetadataLayer->GetLayerDefn());
        poFeature->SetField(GNM_SYSFIELD_PARAMNAME, CPLSPrintf("%s%d",
                                                            GNM_MD_RULE, i + 1));
        poFeature->SetField(GNM_SYSFIELD_PARAMVALUE, m_asRules[i]);
        if(m_poMetadataLayer->CreateFeature(poFeature) != OGRERR_NONE)
        {
            CPLError( CE_Failure, CPLE_AppDefined, "Write rule '%s' failed",
                      m_asRules[i].c_str());
            // TODO: do we need interrupt here?
            //OGRFeature::DestroyFeature( poFeature );
            // return CE_Failure;
        }
        OGRFeature::DestroyFeature(poFeature);
    }
}

GNMGFID GNMGenericNetwork::GetNewVirtualFID()
{
    return --m_nVirtualConnectionGID;
}

void GNMGenericNetwork::FillResultLayer(OGRGNMWrappedResultLayer *poResLayer,
                                        const GNMPATH &path, int nNoOfPath,
                                        bool bReturnVertices, bool bReturnEdges)
{
    for(size_t i = 0; i < path.size(); ++i)
    {
        if(bReturnVertices)
        {
            GNMGFID nGFID = path[i].first;

            // TODO: create feature for virtual vertex
            // if(nGFID < -1) {...}

            CPLString soLayerName = m_moFeatureFIDMap[nGFID];
            OGRFeature* poFeature = GetFeatureByGlobalFID(nGFID);
            if(NULL != poFeature)
            {
                poResLayer->InsertFeature(poFeature, soLayerName, nNoOfPath,
                                          false);

                OGRFeature::DestroyFeature(poFeature);
            }
        }

        if(bReturnEdges)
        {
            GNMGFID nGFID = path[i].second;

            // TODO: create feature for virtual edge
            // if(nGFID < -1) {...}

            CPLString soLayerName = m_moFeatureFIDMap[nGFID];
            OGRFeature* poFeature = GetFeatureByGlobalFID(nGFID);
            if(NULL != poFeature)
            {
                poResLayer->InsertFeature(poFeature, soLayerName, nNoOfPath,
                                          true);
                OGRFeature::DestroyFeature(poFeature);
            }
        }
    }
}

CPLErr GNMGenericNetwork::CheckLayerDriver(const char* pszDefaultDriverName,
                                        char **papszOptions)
{
    if(NULL == m_poLayerDriver)
    {
        const char* pszDriverName = CSLFetchNameValueDef(papszOptions,
                                                         GNM_MD_FORMAT,
                                                         pszDefaultDriverName);

        if(!CheckStorageDriverSupport(pszDriverName))
        {
            CPLError( CE_Failure, CPLE_IllegalArg, "%s driver not supported as network storage",
                      pszDriverName );
            return CE_Failure;
        }

        m_poLayerDriver = GetGDALDriverManager()->GetDriverByName(pszDriverName );
        if(NULL == m_poLayerDriver)
        {
            CPLError( CE_Failure, CPLE_IllegalArg, "%s driver not available",
                      pszDriverName );
            return CE_Failure;
        }
    }
    return CE_None;
}

CPLErr GNMGenericNetwork::CreateMetadataLayer(GDALDataset * const pDS, int nVersion,
                                           size_t nFieldSize)
{
    OGRLayer* pMetadataLayer = pDS->CreateLayer(GNM_SYSLAYER_META, NULL, wkbNone,
                                                NULL);
    if (NULL == pMetadataLayer)
    {
        CPLError( CE_Failure, CPLE_AppDefined, "Creation of '%s' layer failed",
                  GNM_SYSLAYER_META );
        return CE_Failure;
    }

    OGRFieldDefn oFieldKey(GNM_SYSFIELD_PARAMNAME, OFTString);
    oFieldKey.SetWidth(static_cast<int>(nFieldSize));
    OGRFieldDefn oFieldValue(GNM_SYSFIELD_PARAMVALUE, OFTString);
    oFieldValue.SetWidth(static_cast<int>(nFieldSize));

    if(pMetadataLayer->CreateField(&oFieldKey) != OGRERR_NONE ||
       pMetadataLayer->CreateField(&oFieldValue) != OGRERR_NONE)
    {
        CPLError( CE_Failure, CPLE_AppDefined, "Creation of layer '%s' fields failed",
                  GNM_SYSLAYER_META );
        return CE_Failure;
    }

    OGRFeature *poFeature;

    // write name
    poFeature = OGRFeature::CreateFeature(pMetadataLayer->GetLayerDefn());
    poFeature->SetField(GNM_SYSFIELD_PARAMNAME, GNM_MD_NAME);
    poFeature->SetField(GNM_SYSFIELD_PARAMVALUE, m_soName);
    if(pMetadataLayer->CreateFeature(poFeature) != OGRERR_NONE)
    {
        OGRFeature::DestroyFeature( poFeature );
        CPLError( CE_Failure, CPLE_AppDefined, "Write GNM name failed");
        return CE_Failure;
    }
    OGRFeature::DestroyFeature(poFeature);

    // write version
    poFeature = OGRFeature::CreateFeature(pMetadataLayer->GetLayerDefn());
    poFeature->SetField(GNM_SYSFIELD_PARAMNAME, GNM_MD_VERSION);
    poFeature->SetField(GNM_SYSFIELD_PARAMVALUE, CPLSPrintf("%d", nVersion));
    if(pMetadataLayer->CreateFeature(poFeature) != OGRERR_NONE)
    {
        OGRFeature::DestroyFeature( poFeature );
        CPLError( CE_Failure, CPLE_AppDefined, "Write GNM version failed");
        return CE_Failure;
    }
    OGRFeature::DestroyFeature(poFeature);

    // write description
    if(!sDescription.empty())
    {
        poFeature = OGRFeature::CreateFeature(pMetadataLayer->GetLayerDefn());
        poFeature->SetField(GNM_SYSFIELD_PARAMNAME, GNM_MD_DESCR);
        poFeature->SetField(GNM_SYSFIELD_PARAMVALUE, sDescription);
        if(pMetadataLayer->CreateFeature(poFeature) != OGRERR_NONE)
        {
            OGRFeature::DestroyFeature( poFeature );
            CPLError( CE_Failure, CPLE_AppDefined, "Write GNM description failed");
            return CE_Failure;
        }
        OGRFeature::DestroyFeature(poFeature);
    }

    // write srs if < 254 or create file
    if(!m_soSRS.empty())
    {
        if(m_soSRS.size() >= nFieldSize)
        {
            if(StoreNetworkSrs() != CE_None)
                return CE_Failure;
        }
        else
        {
            poFeature = OGRFeature::CreateFeature(pMetadataLayer->GetLayerDefn());
            poFeature->SetField(GNM_SYSFIELD_PARAMNAME, GNM_MD_SRS);
            poFeature->SetField(GNM_SYSFIELD_PARAMVALUE, m_soSRS);
            if(pMetadataLayer->CreateFeature(poFeature) != OGRERR_NONE)
            {
                OGRFeature::DestroyFeature( poFeature );
                CPLError( CE_Failure, CPLE_AppDefined, "Write GNM SRS failed");
                return CE_Failure;
            }
            OGRFeature::DestroyFeature(poFeature);
        }
    }

    m_poMetadataLayer = pMetadataLayer;

    m_nVersion = nVersion;

    // create default rule
    return CreateRule("ALLOW CONNECTS ANY");
}

CPLErr GNMGenericNetwork::StoreNetworkSrs()
{
    return CE_Failure;
}

CPLErr GNMGenericNetwork::LoadNetworkSrs()
{
    return CE_Failure;
}

CPLErr GNMGenericNetwork::CreateGraphLayer(GDALDataset * const pDS)
{
    m_poGraphLayer = pDS->CreateLayer(GNM_SYSLAYER_GRAPH, NULL, wkbNone, NULL);
    if (NULL == m_poGraphLayer)
    {
        CPLError( CE_Failure, CPLE_AppDefined, "Creation of '%s' layer failed",
                  GNM_SYSLAYER_GRAPH );
        return CE_Failure;
    }

    OGRFieldDefn oFieldSrc(GNM_SYSFIELD_SOURCE, GNMGFIDInt);
    OGRFieldDefn oFieldDst(GNM_SYSFIELD_TARGET, GNMGFIDInt);
    OGRFieldDefn oFieldConnector(GNM_SYSFIELD_CONNECTOR, GNMGFIDInt);
    OGRFieldDefn oFieldCost(GNM_SYSFIELD_COST, OFTReal);
    OGRFieldDefn oFieldInvCost(GNM_SYSFIELD_INVCOST, OFTReal);
    OGRFieldDefn oFieldDir(GNM_SYSFIELD_DIRECTION, OFTInteger);
    OGRFieldDefn oFieldBlock(GNM_SYSFIELD_BLOCKED, OFTInteger);

    if(m_poGraphLayer->CreateField(&oFieldSrc) != OGRERR_NONE ||
       m_poGraphLayer->CreateField(&oFieldDst) != OGRERR_NONE ||
       m_poGraphLayer->CreateField(&oFieldConnector) != OGRERR_NONE ||
       m_poGraphLayer->CreateField(&oFieldCost) != OGRERR_NONE ||
       m_poGraphLayer->CreateField(&oFieldInvCost) != OGRERR_NONE ||
       m_poGraphLayer->CreateField(&oFieldDir) != OGRERR_NONE ||
       m_poGraphLayer->CreateField(&oFieldBlock) != OGRERR_NONE)
    {
        CPLError( CE_Failure, CPLE_AppDefined, "Creation of layer '%s' fields failed",
                  GNM_SYSLAYER_GRAPH );
        return CE_Failure;
    }

    return CE_None;
}

CPLErr GNMGenericNetwork::CreateFeaturesLayer(GDALDataset * const pDS)
{
    m_poFeaturesLayer = pDS->CreateLayer(GNM_SYSLAYER_FEATURES, NULL, wkbNone, NULL);
    if (NULL == m_poFeaturesLayer)
    {
        CPLError( CE_Failure, CPLE_AppDefined, "Creation of '%s' layer failed",
                  GNM_SYSLAYER_FEATURES );
        return CE_Failure;
    }

    OGRFieldDefn oFieldGID(GNM_SYSFIELD_GFID, GNMGFIDInt);
    OGRFieldDefn oFieldLayerName(GNM_SYSFIELD_LAYERNAME, OFTString);
    oFieldLayerName.SetWidth(254);

    if(m_poFeaturesLayer->CreateField(&oFieldGID) != OGRERR_NONE ||
       m_poFeaturesLayer->CreateField(&oFieldLayerName) != OGRERR_NONE)
    {
        CPLError( CE_Failure, CPLE_AppDefined, "Creation of layer '%s' fields failed",
                  GNM_SYSLAYER_FEATURES );
        return CE_Failure;
    }

    return CE_None;
}

CPLErr GNMGenericNetwork::LoadMetadataLayer(GDALDataset * const pDS)
{
    // read version, description, SRS, classes, rules
    m_poMetadataLayer = pDS->GetLayerByName(GNM_SYSLAYER_META);
    if(NULL == m_poMetadataLayer)
    {
        CPLError( CE_Failure, CPLE_AppDefined, "Loading of '%s' layer failed",
                  GNM_SYSLAYER_META );
        return CE_Failure;
    }

    std::map<int, GNMRule> moRules;
    int nRulePrefixLen = static_cast<int>(CPLStrnlen(GNM_MD_RULE, 255));
    OGRFeature *poFeature;
    m_poMetadataLayer->ResetReading();
    while ((poFeature = m_poMetadataLayer->GetNextFeature()) != NULL)
    {
        const char *pKey = poFeature->GetFieldAsString(GNM_SYSFIELD_PARAMNAME);
        const char *pValue = poFeature->GetFieldAsString(GNM_SYSFIELD_PARAMVALUE);

        CPLDebug("GNM", "Load metadata. Key: %s, value %s", pKey, pValue);

        if(EQUAL(pKey, GNM_MD_NAME))
        {
            m_soName = pValue;
        }
        else if(EQUAL(pKey, GNM_MD_DESCR))
        {
            sDescription = pValue;
        }
        else if(EQUAL(pKey, GNM_MD_SRS))
        {
            m_soSRS = pValue;
        }
        else if(EQUAL(pKey, GNM_MD_VERSION))
        {
            m_nVersion = atoi(pValue);
        }
        else if(EQUALN(pKey, GNM_MD_RULE, nRulePrefixLen))
        {
            moRules[atoi(pKey + nRulePrefixLen)] = pValue;
        }

        OGRFeature::DestroyFeature(poFeature);
    }

    for(std::map<int, GNMRule>::iterator it =  moRules.begin();
        it != moRules.end(); ++it)
    {
        if(it->second.IsValid())
            m_asRules.push_back(it->second);
    }

    if(m_soSRS.empty())
    {
        if(LoadNetworkSrs() != CE_None)
            return CE_Failure;
    }

    return CE_None;
}

CPLErr GNMGenericNetwork::LoadGraphLayer(GDALDataset * const pDS)
{
    m_poGraphLayer = pDS->GetLayerByName(GNM_SYSLAYER_GRAPH);
    if(NULL == m_poGraphLayer)
    {
        CPLError( CE_Failure, CPLE_AppDefined, "Loading of '%s' layer failed",
                  GNM_SYSLAYER_GRAPH );
        return CE_Failure;
    }

    return CE_None;
}

CPLErr GNMGenericNetwork::LoadGraph()
{
    if(m_bIsGraphLoaded)
        return CE_None;

    if(NULL == m_poGraphLayer)
    {
        CPLError( CE_Failure, CPLE_AppDefined, "Loading of graph data failed");
        return CE_Failure;
    }

    OGRFeature *poFeature;
    m_poGraphLayer->ResetReading();
    GNMGFID nSrcFID, nTgtFID, nConFID;
    double dfCost, dfInvCost;
    while ((poFeature = m_poGraphLayer->GetNextFeature()) != NULL)
    {
        nSrcFID = poFeature->GetFieldAsGNMGFID(GNM_SYSFIELD_SOURCE);
        nTgtFID = poFeature->GetFieldAsGNMGFID(GNM_SYSFIELD_TARGET);
        nConFID = poFeature->GetFieldAsGNMGFID(GNM_SYSFIELD_CONNECTOR);
        dfCost = poFeature->GetFieldAsDouble(GNM_SYSFIELD_COST);
        dfInvCost = poFeature->GetFieldAsDouble(GNM_SYSFIELD_INVCOST);
        GNMDirection eDir = poFeature->GetFieldAsInteger(GNM_SYSFIELD_DIRECTION);

        int nBlockState = poFeature->GetFieldAsInteger(GNM_SYSFIELD_BLOCKED);

        bool bIsBlock = GNM_BLOCK_NONE != nBlockState;

        m_oGraph.AddEdge(nConFID, nSrcFID, nTgtFID, eDir == GNM_EDGE_DIR_BOTH,
                         dfCost, dfInvCost);

        if(bIsBlock)
        {
            if(nBlockState & GNM_BLOCK_SRC)
                m_oGraph.ChangeBlockState(nSrcFID, bIsBlock);
            if(nBlockState & GNM_BLOCK_TGT)
                m_oGraph.ChangeBlockState(nTgtFID, bIsBlock);
            if(nBlockState & GNM_BLOCK_CONN)
                m_oGraph.ChangeBlockState(nConFID, bIsBlock);
        }

        if(nConFID < m_nVirtualConnectionGID)
            m_nVirtualConnectionGID = nConFID;

        OGRFeature::DestroyFeature(poFeature);
    }

    m_bIsGraphLoaded = true;
    return CE_None;
}

CPLErr GNMGenericNetwork::LoadFeaturesLayer(GDALDataset * const pDS)
{
    m_poFeaturesLayer = pDS->GetLayerByName(GNM_SYSLAYER_FEATURES);
    if(NULL == m_poFeaturesLayer)
    {
        CPLError( CE_Failure, CPLE_AppDefined, "Loading of '%s' layer failed",
                  GNM_SYSLAYER_FEATURES );
        return CE_Failure;
    }

    OGRFeature *poFeature;
    m_poFeaturesLayer->ResetReading();
    while ((poFeature = m_poFeaturesLayer->GetNextFeature()) != NULL)
    {
        GNMGFID nFID = poFeature->GetFieldAsGNMGFID(GNM_SYSFIELD_GFID);
        const char *pFeatureClass = poFeature->GetFieldAsString(
                    GNM_SYSFIELD_LAYERNAME);

        if(nFID >= m_nGID)
            m_nGID = nFID + 1;

        m_moFeatureFIDMap[nFID] = pFeatureClass;

        // Load network layer. No error handling as we want to load whole network
        LoadNetworkLayer(pFeatureClass);

        OGRFeature::DestroyFeature(poFeature);
    }
    return CE_None;
}

int GNMGenericNetwork::TestCapability( const char * pszCap )

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

OGRLayer *GNMGenericNetwork::CopyLayer(OGRLayer *poSrcLayer,
                                       const char *pszNewName, char **papszOptions)
{
    if(CSLFindName(papszOptions, "DST_SRSWKT") == -1)
    {
        papszOptions = CSLAddNameValue(papszOptions, "DST_SRSWKT",
                                       GetProjectionRef());
    }
    else
    {
        papszOptions = CSLSetNameValue(papszOptions, "DST_SRSWKT",
                                       GetProjectionRef());
    }
    return GDALDataset::CopyLayer(poSrcLayer, pszNewName, papszOptions);
}

int GNMGenericNetwork::CloseDependentDatasets()
{
    size_t nCount = m_apoLayers.size();
    for(size_t i = 0; i < nCount; ++i)
    {
        delete m_apoLayers[i];
    }
    m_apoLayers.clear();

    GNMNetwork::CloseDependentDatasets();

    return nCount > 0 ? TRUE : FALSE;
}

void GNMGenericNetwork::FlushCache()
{
    SaveRules();

    GNMNetwork::FlushCache();
}

//--- C API --------------------------------------------------------------------

CPLErr CPL_STDCALL GNMConnectFeatures (GNMGenericNetworkH hNet,
                                GNMGFID nSrcFID, GNMGFID nTgtFID,
                                GNMGFID nConFID, double dfCost,
                                double dfInvCost,
                                GNMDirection eDir)
{
    VALIDATE_POINTER1( hNet, "GNMConnectFeatures", CE_Failure );

    return ((GNMGenericNetwork*)hNet)->ConnectFeatures(nSrcFID, nTgtFID,
                                                          nConFID, dfCost,
                                                          dfInvCost, eDir);
}

CPLErr CPL_STDCALL GNMDisconnectFeatures (GNMGenericNetworkH hNet, GNMGFID nSrcFID,
                                          GNMGFID nTgtFID, GNMGFID nConFID)
{
    VALIDATE_POINTER1( hNet, "GNMDisconnectFeatures", CE_Failure );

    return ((GNMGenericNetwork*)hNet)->DisconnectFeatures(nSrcFID, nTgtFID,
                                                          nConFID);
}

CPLErr CPL_STDCALL GNMDisconnectFeaturesWithId(GNMGenericNetworkH hNet,
                                               GNMGFID nFID)
{
    VALIDATE_POINTER1( hNet, "GNMDisconnectFeaturesWithId", CE_Failure );

    return ((GNMGenericNetwork*)hNet)->DisconnectFeaturesWithId(nFID);

}


CPLErr CPL_STDCALL GNMReconnectFeatures (GNMGenericNetworkH hNet,
                                         GNMGFID nSrcFID, GNMGFID nTgtFID,
                                         GNMGFID nConFID, double dfCost,
                                         double dfInvCost, GNMDirection eDir)
{
    VALIDATE_POINTER1( hNet, "GNMReconnectFeatures", CE_Failure );

    return ((GNMGenericNetwork*)hNet)->ReconnectFeatures(nSrcFID, nTgtFID,
                                        nConFID, dfCost, dfInvCost, eDir);

}

CPLErr CPL_STDCALL GNMCreateRule (GNMGenericNetworkH hNet, const char *pszRuleStr)
{
    VALIDATE_POINTER1( hNet, "GNMCreateRule", CE_Failure );

    return ((GNMGenericNetwork*)hNet)->CreateRule(pszRuleStr);

}

CPLErr CPL_STDCALL GNMDeleteAllRules(GNMGenericNetworkH hNet)
{
    VALIDATE_POINTER1( hNet, "GNMDeleteAllRules", CE_Failure );

    return ((GNMGenericNetwork*)hNet)->DeleteAllRules();
}

CPLErr CPL_STDCALL GNMDeleteRule(GNMGenericNetworkH hNet, const char *pszRuleStr)
{
    VALIDATE_POINTER1( hNet, "GNMDeleteRule", CE_Failure );

    return ((GNMGenericNetwork*)hNet)->DeleteRule(pszRuleStr);
}

char** CPL_STDCALL GNMGetRules(GNMGenericNetworkH hNet)
{
    VALIDATE_POINTER1( hNet, "GNMDeleteRule", NULL );

    return ((GNMGenericNetwork*)hNet)->GetRules();
}

CPLErr CPL_STDCALL GNMConnectPointsByLines (GNMGenericNetworkH hNet,
                                            char **papszLayerList,
                                            double dfTolerance,
                                            double dfCost,
                                            double dfInvCost,
                                            GNMDirection eDir)
{
    VALIDATE_POINTER1( hNet, "GNMConnectPointsByLines", CE_Failure );

    return ((GNMGenericNetwork*)hNet)->ConnectPointsByLines(papszLayerList,
                                                            dfTolerance,
                                                            dfCost,
                                                            dfInvCost, eDir);
}

CPLErr CPL_STDCALL GNMChangeBlockState (GNMGenericNetworkH hNet,
                                        GNMGFID nFID, bool bIsBlock)
{
    VALIDATE_POINTER1( hNet, "GNMChangeBlockState", CE_Failure );

    return ((GNMGenericNetwork*)hNet)->ChangeBlockState(nFID, bIsBlock);
}

CPLErr CPL_STDCALL GNMChangeAllBlockState (GNMGenericNetworkH hNet,
                                           int bIsBlock)
{
    VALIDATE_POINTER1( hNet, "GNMChangeAllBlockState", CE_Failure );

    return ((GNMGenericNetwork*)hNet)->ChangeAllBlockState(bIsBlock == TRUE);
}
