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

 *

 * Project:  OGR

 * Purpose:  OGRNASDriver implementation

 * Author:   Frank Warmerdam, warmerdam@pobox.com

 *

 ******************************************************************************

 * Copyright (c) 2002, Frank Warmerdam <warmerdam@pobox.com>

 *

 * SPDX-License-Identifier: MIT

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

#include "cpl_conv.h"

#include "cpl_multiproc.h"

#include "nasreaderp.h"

#include "ogr_nas.h"

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

/*                     OGRNASDriverIdentify()                           */

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

static int OGRNASDriverIdentify(GDALOpenInfo *poOpenInfo)

{

    if (poOpenInfo->fpL == nullptr)

        return FALSE;

    /* -------------------------------------------------------------------- */

    /*      Check for a UTF-8 BOM and skip if found                         */

    /*                                                                      */

    /*      TODO: BOM is variable-length parameter and depends on encoding. */

    /*            Add BOM detection for other encodings.                    */

    /* -------------------------------------------------------------------- */

    // Used to skip to actual beginning of XML data

    const char *pszPtr = reinterpret_cast<const char *>(poOpenInfo->pabyHeader);

    // Skip UTF-8 BOM

    if (poOpenInfo->nHeaderBytes > 3 &&

        memcmp(poOpenInfo->pabyHeader, "\xEF\xBB\xBF", 3) == 0)

    {

        pszPtr += 3;

    }

    // Skip spaces

    while (*pszPtr && std::isspace(static_cast<unsigned char>(*pszPtr)))

        ++pszPtr;

    /* -------------------------------------------------------------------- */

    /*      Here, we expect the opening chevrons of NAS tree root element   */

    /* -------------------------------------------------------------------- */

    if (pszPtr[0] != '<')

        return FALSE;

    if (poOpenInfo->IsSingleAllowedDriver("NAS"))

        return TRUE;

    // TryToIngest() invalidates above pszPtr

    pszPtr = nullptr;

    CPL_IGNORE_RET_VAL(pszPtr);

    if (!poOpenInfo->TryToIngest(8192))

        return FALSE;

    pszPtr = reinterpret_cast<const char *>(poOpenInfo->pabyHeader);

    if (strstr(pszPtr, "opengis.net/gml") == nullptr)

        return FALSE;

    char **papszIndicators = CSLTokenizeStringComplex(

        CPLGetConfigOption("NAS_INDICATOR",

                           "NAS-Operationen;AAA-Fachschema;aaa.xsd;aaa-suite"),

        ";", 0, 0);

    bool bFound = false;

    for (int i = 0; papszIndicators[i] && !bFound; i++)

    {

        bFound = strstr(pszPtr, papszIndicators[i]) != nullptr;

    }

    CSLDestroy(papszIndicators);

    // Require NAS_GFS_TEMPLATE to be defined

    if (bFound && !CPLGetConfigOption("NAS_GFS_TEMPLATE", nullptr))

    {

        CPLDebug("NAS",

                 "This file could be recognized by the NAS driver. "

                 "If this is desired, you need to define the NAS_GFS_TEMPLATE "

                 "configuration option.");

        return FALSE;

    }

    return bFound;

}

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

/*                                Open()                                */

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

static GDALDataset *OGRNASDriverOpen(GDALOpenInfo *poOpenInfo)

{

    if (poOpenInfo->eAccess == GA_Update || !OGRNASDriverIdentify(poOpenInfo))

        return nullptr;

    VSIFCloseL(poOpenInfo->fpL);

    poOpenInfo->fpL = nullptr;

    OGRNASDataSource *poDS = new OGRNASDataSource();

    if (!poDS->Open(poOpenInfo->pszFilename))

    {

        delete poDS;

        return nullptr;

    }

    return poDS;

}

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

/*                           RegisterOGRNAS()                           */

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

void RegisterOGRNAS()

{

    if (GDALGetDriverByName("NAS") != nullptr)

        return;

    GDALDriver *poDriver = new GDALDriver();

    poDriver->SetDescription("NAS");

    poDriver->SetMetadataItem(GDAL_DCAP_VECTOR, "YES");

    poDriver->SetMetadataItem(GDAL_DMD_LONGNAME, "NAS - ALKIS");

    poDriver->SetMetadataItem(GDAL_DMD_EXTENSION, "xml");

    poDriver->SetMetadataItem(GDAL_DMD_HELPTOPIC, "drivers/vector/nas.html");

    poDriver->SetMetadataItem(GDAL_DCAP_VIRTUALIO, "YES");

    poDriver->SetMetadataItem(GDAL_DMD_SUPPORTED_SQL_DIALECTS, "OGRSQL SQLITE");

    poDriver->pfnOpen = OGRNASDriverOpen;

    poDriver->pfnIdentify = OGRNASDriverIdentify;

    GetGDALDriverManager()->RegisterDriver(poDriver);

}