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

 *

 * Project:  GDAL

 * Purpose:  Implementation of NOAA .b format used for GEOCON / NADCON5 grids

 * Author:   Even Rouault <even dot rouault at spatialys.com>

 *

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

 * Copyright (c) 2022, Even Rouault <even dot rouault at spatialys.com>

 *

 * SPDX-License-Identifier: MIT

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

#include "cpl_conv.h"

#include "cpl_string.h"

#include "gdal_frmts.h"

#include "gdal_priv.h"

#include "rawdataset.h"

#include "ogr_srs_api.h"

#include <limits>

// Specification of the format is at "paragraph 10.2 ".b" grids (GEOCON and

// NADCON 5.0)" of "NOAA Technical Report NOS NGS 63" at

// https://geodesy.noaa.gov/library/pdfs/NOAA_TR_NOS_NGS_0063.pdf

constexpr int HEADER_SIZE = 52;

constexpr int FORTRAN_HEADER_SIZE = 4;

constexpr int FORTRAN_TRAILER_SIZE = 4;

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

/* ==================================================================== */

/*                          NOAA_B_Dataset                              */

/* ==================================================================== */

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

class NOAA_B_Dataset final : public RawDataset

{

    OGRSpatialReference m_oSRS{};

    GDALGeoTransform m_gt{};

    CPL_DISALLOW_COPY_ASSIGN(NOAA_B_Dataset)

    static int IdentifyEx(GDALOpenInfo *poOpenInfo, bool &bBigEndianOut);

    CPLErr Close(GDALProgressFunc = nullptr, void * = nullptr) override

    {

        return GDALPamDataset::Close();

    }

  public:

    NOAA_B_Dataset()

    {

        m_oSRS.SetAxisMappingStrategy(OAMS_TRADITIONAL_GIS_ORDER);

    }

    CPLErr GetGeoTransform(GDALGeoTransform &gt) const override;

    const OGRSpatialReference *GetSpatialRef() const override

    {

        return &m_oSRS;

    }

    static GDALDataset *Open(GDALOpenInfo *);

    static int Identify(GDALOpenInfo *);

};

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

/* ==================================================================== */

/*                          NOAA_B_Dataset                              */

/* ==================================================================== */

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

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

/*                          GetHeaderValues()                           */

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

static void GetHeaderValues(const GDALOpenInfo *poOpenInfo, double &dfSWLat,

                            double &dfSWLon, double &dfDeltaLat,

                            double &dfDeltaLon, int32_t &nRows, int32_t &nCols,

                            int32_t &iKind, bool bBigEndian)

{

    const auto ReadFloat64 = [bBigEndian](const GByte *&ptr)

    {

        double v;

        memcpy(&v, ptr, sizeof(v));

        ptr += sizeof(v);

        if (bBigEndian)

            CPL_MSBPTR64(&v);

        else

            CPL_LSBPTR64(&v);

        return v;

    };

    const auto ReadInt32 = [bBigEndian](const GByte *&ptr)

    {

        int32_t v;

        memcpy(&v, ptr, sizeof(v));

        ptr += sizeof(v);

        if (bBigEndian)

            CPL_MSBPTR32(&v);

        else

            CPL_LSBPTR32(&v);

        return v;

    };

    const GByte *ptr = poOpenInfo->pabyHeader + FORTRAN_HEADER_SIZE;

    dfSWLat = ReadFloat64(ptr);

    dfSWLon = ReadFloat64(ptr);

    dfDeltaLat = ReadFloat64(ptr);

    dfDeltaLon = ReadFloat64(ptr);

    nRows = ReadInt32(ptr);

    nCols = ReadInt32(ptr);

    iKind = ReadInt32(ptr);

}

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

/*                              Identify()                              */

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

int NOAA_B_Dataset::IdentifyEx(GDALOpenInfo *poOpenInfo, bool &bBigEndianOut)

{

    if (poOpenInfo->nHeaderBytes < HEADER_SIZE)

        return FALSE;

#if !defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION)

    if (!poOpenInfo->IsExtensionEqualToCI("b"))

        return FALSE;

#endif

    // Sanity checks on header

    double dfSWLat;

    double dfSWLon;

    double dfDeltaLat;

    double dfDeltaLon;

    int32_t nRows;

    int32_t nCols;

    int32_t iKind;

    // Fun... nadcon5 files are encoded in big-endian, but vertcon3 files...

    // in little-endian. We could probably figure that out directly from the

    // 4 bytes which are 0x00 0x00 0x00 0x2C for nadcon5, and the reverse for

    // vertcon3, but the semantics of those 4 bytes is undocumented.

    // So try both possibilities and rely on sanity checks.

    for (int i = 0; i < 2; ++i)

    {

        const bool bBigEndian = i == 0 ? true : false;

        GetHeaderValues(poOpenInfo, dfSWLat, dfSWLon, dfDeltaLat, dfDeltaLon,

                        nRows, nCols, iKind, bBigEndian);

        if (!(fabs(dfSWLat) <= 90))

            continue;

        if (!(fabs(dfSWLon) <=

              360))  // NADCON5 grids typically have SWLon > 180

            continue;

        if (!(dfDeltaLat > 0 && dfDeltaLat <= 1))

            continue;

        if (!(dfDeltaLon > 0 && dfDeltaLon <= 1))

            continue;

        if (!(nRows > 0 && dfSWLat + (nRows - 1) * dfDeltaLat <= 90))

            continue;

        if (!(nCols > 0 && (nCols - 1) * dfDeltaLon <= 360))

            continue;

        if (!(iKind >= -1 && iKind <= 2))

            continue;

        bBigEndianOut = bBigEndian;

        return TRUE;

    }

    return FALSE;

}

int NOAA_B_Dataset::Identify(GDALOpenInfo *poOpenInfo)

{

    bool bBigEndian = false;

    return IdentifyEx(poOpenInfo, bBigEndian);

}

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

/*                          GetGeoTransform()                           */

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

CPLErr NOAA_B_Dataset::GetGeoTransform(GDALGeoTransform &gt) const

{

    gt = m_gt;

    return CE_None;

}

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

/*                                Open()                                */

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

GDALDataset *NOAA_B_Dataset::Open(GDALOpenInfo *poOpenInfo)

{

    bool bBigEndian = false;

    if (!IdentifyEx(poOpenInfo, bBigEndian) || poOpenInfo->fpL == nullptr ||

        poOpenInfo->eAccess == GA_Update)

    {

        return nullptr;

    }

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

    /*      Read the header.                                                */

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

    double dfSWLat;

    double dfSWLon;

    double dfDeltaLat;

    double dfDeltaLon;

    int32_t nRows;

    int32_t nCols;

    int32_t iKind;

    GetHeaderValues(poOpenInfo, dfSWLat, dfSWLon, dfDeltaLat, dfDeltaLon, nRows,

                    nCols, iKind, bBigEndian);

    if (iKind == -1)

    {

        CPLError(CE_Failure, CPLE_NotSupported,

                 "KIND = -1 in NOAA .b dataset not supported");

        return nullptr;

    }

    const GDALDataType eDT =

        // iKind == -1 ? GDT_Int16 :

        iKind == 0   ? GDT_Int32

        : iKind == 1 ? GDT_Float32

                     : GDT_Int16;

    const int nDTSize = GDALGetDataTypeSizeBytes(eDT);

    if (!GDALCheckDatasetDimensions(nCols, nRows) ||

        (nDTSize > 0 && static_cast<vsi_l_offset>(nCols) * nRows >

                            std::numeric_limits<vsi_l_offset>::max() / nDTSize))

    {

        return nullptr;

    }

    if (nDTSize > 0 && nCols > (std::numeric_limits<int>::max() -

                                FORTRAN_HEADER_SIZE - FORTRAN_TRAILER_SIZE) /

                                   nDTSize)

    {

        return nullptr;

    }

    const int nLineSize =

        FORTRAN_HEADER_SIZE + nCols * nDTSize + FORTRAN_TRAILER_SIZE;

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

    /*      Create a corresponding GDALDataset.                             */

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

    auto poDS = std::make_unique<NOAA_B_Dataset>();

    poDS->nRasterXSize = nCols;

    poDS->nRasterYSize = nRows;

    // Adjust longitude > 180 to [-180, 180] range

    if (dfSWLon > 180)

        dfSWLon -= 360;

    // Convert from south-west center-of-pixel convention to

    // north-east pixel-corner convention

    poDS->m_gt.xorig = dfSWLon - dfDeltaLon / 2;

    poDS->m_gt.xscale = dfDeltaLon;

    poDS->m_gt.xrot = 0.0;

    poDS->m_gt.yorig = dfSWLat + (nRows - 1) * dfDeltaLat + dfDeltaLat / 2;

    poDS->m_gt.yrot = 0.0;

    poDS->m_gt.yscale = -dfDeltaLat;

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

    /*      Create band information object.                                 */

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

    // Borrow file handle

    VSILFILE *fpImage = poOpenInfo->fpL;

    poOpenInfo->fpL = nullptr;

    // Records are presented from the southern-most to the northern-most

    auto poBand = RawRasterBand::Create(

        poDS.get(), 1, fpImage,

        // skip to beginning of northern-most line

        HEADER_SIZE +

            static_cast<vsi_l_offset>(poDS->nRasterYSize - 1) * nLineSize +

            FORTRAN_HEADER_SIZE,

        nDTSize, -nLineSize, eDT,

        bBigEndian ? RawRasterBand::ByteOrder::ORDER_BIG_ENDIAN

                   : RawRasterBand::ByteOrder::ORDER_LITTLE_ENDIAN,

        RawRasterBand::OwnFP::YES);

    if (!poBand)

        return nullptr;

    poDS->SetBand(1, std::move(poBand));

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

    /*      Guess CRS from filename.                                        */

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

    const std::string osFilename(CPLGetFilename(poOpenInfo->pszFilename));

    static const struct

    {

        const char *pszPrefix;

        int nEPSGCode;

    }

    // Cf https://geodesy.noaa.gov/pub/nadcon5/20160901release/Builds/

    asFilenameToCRS[] = {

        {"nadcon5.nad27.", 4267},       // NAD27

        {"nadcon5.pr40.", 4139},        // Puerto Rico (1940)

        {"nadcon5.ohd.", 4135},         // Old Hawaian

        {"nadcon5.sl1952.", 4136},      // Saint Lawrence Island (1952)

        {"nadcon5.sp1952.", 4137},      // Saint Paul Island (1952)

        {"nadcon5.sg1952.", 4138},      // Saint George Island (1952)

        {"nadcon5.as62.", 4169},        // American Samoa 1962

        {"nadcon5.gu63.", 4675},        // Guam 1963

        {"nadcon5.nad83_1986.", 4269},  // NAD83

        {"nadcon5.nad83_harn.", 4152},  // NAD83(HARN)

        {"nadcon5.nad83_1992.",

         4152},  // NAD83(1992) for Alaska is NAD83(HARN) in EPSG

        {"nadcon5.nad83_1993.",

         4152},  // NAD83(1993) for American Samoa, PRVI, Guam and Hawaii is

                 // NAD83(HARN) in EPSG

        {"nadcon5.nad83_1997.", 8545},  // NAD83(HARN Corrected)

        {"nadcon5.nad83_fbn.", 8860},   // NAD83(FBN)

        {"nadcon5.nad83_2002.",

         8860},  // NAD83(2002) for Alaska, PRVI and Guam is NAD83(FBN) in EPSG

        {"nadcon5.nad83_2007.", 4759},  // NAD83(NSRS2007)

    };

    for (const auto &sPair : asFilenameToCRS)

    {

        if (STARTS_WITH_CI(osFilename.c_str(), sPair.pszPrefix))

        {

            poDS->m_oSRS.importFromEPSG(sPair.nEPSGCode);

            break;

        }

    }

    if (poDS->m_oSRS.IsEmpty())

    {

        poDS->m_oSRS.importFromWkt(

            "GEOGCRS[\"Unspecified geographic CRS\",DATUM[\"Unspecified datum "

            "based on GRS80 ellipsoid\",ELLIPSOID[\"GRS "

            "1980\",6378137,298.257222101]],CS[ellipsoidal,2],AXIS[\"geodetic "

            "latitude (Lat)\",north,ANGLEUNIT[\"degree\",0.0174532925199433]], "

            "       AXIS[\"geodetic longitude "

            "(Lon)\",east,ORDER[2],ANGLEUNIT[\"degree\",0.0174532925199433]]]");

    }

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

    /*      Initialize any PAM information.                                 */

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

    poDS->SetDescription(poOpenInfo->pszFilename);

    poDS->TryLoadXML();

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

    /*      Check for overviews.                                            */

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

    poDS->oOvManager.Initialize(poDS.get(), poOpenInfo->pszFilename);

    return poDS.release();

}

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

/*                        GDALRegister_NOAA_B()                         */

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

void GDALRegister_NOAA_B()

{

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

        return;

    GDALDriver *poDriver = new GDALDriver();

    poDriver->SetDescription("NOAA_B");

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

    poDriver->SetMetadataItem(GDAL_DMD_LONGNAME,

                              "NOAA GEOCON/NADCON5 .b format");

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

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

    poDriver->SetMetadataItem(GDAL_DMD_HELPTOPIC, "drivers/raster/noaa_b.html");

    poDriver->pfnIdentify = NOAA_B_Dataset::Identify;

    poDriver->pfnOpen = NOAA_B_Dataset::Open;

    GetGDALDriverManager()->RegisterDriver(poDriver);

}