/******************************************************************************
 *
 * Project:  PNM Driver
 * Purpose:  Portable anymap file format implementation
 * Author:   Frank Warmerdam, warmerdam@pobox.com
 *
 ******************************************************************************
 * Copyright (c) 2001, Frank Warmerdam
 * Copyright (c) 2008-2011, Even Rouault <even dot rouault at spatialys.com>
 *
 * SPDX-License-Identifier: MIT
 ****************************************************************************/

#include "cpl_string.h"
#include "gdal_frmts.h"
#include "gdal_priv.h"
#include "rawdataset.h"

#include <algorithm>
#include <cctype>

/************************************************************************/
/* ==================================================================== */
/*                              PNMDataset                              */
/* ==================================================================== */
/************************************************************************/

class PNMDataset final : public RawDataset
{
    VSILFILE *fpImage = nullptr;  // Image data file.

    bool bGeoTransformValid{};
    GDALGeoTransform m_gt{};

    CPL_DISALLOW_COPY_ASSIGN(PNMDataset)

    CPLErr Close() override;

  public:
    PNMDataset() = default;
    ~PNMDataset() override;

    CPLErr GetGeoTransform(GDALGeoTransform &gt) const override;

    static int Identify(GDALOpenInfo *);
    static GDALDataset *Open(GDALOpenInfo *);
    static GDALDataset *Create(const char *pszFilename, int nXSize, int nYSize,
                               int nBandsIn, GDALDataType eType,
                               char **papszOptions);
};

/************************************************************************/
/*                            ~PNMDataset()                            */
/************************************************************************/

PNMDataset::~PNMDataset()

{
    PNMDataset::Close();
}

/************************************************************************/
/*                              Close()                                 */
/************************************************************************/

CPLErr PNMDataset::Close()
{
    CPLErr eErr = CE_None;
    if (nOpenFlags != OPEN_FLAGS_CLOSED)
    {
        if (PNMDataset::FlushCache(true) != CE_None)
            eErr = CE_Failure;

        if (fpImage)
        {
            if (VSIFCloseL(fpImage) != 0)
            {
                CPLError(CE_Failure, CPLE_FileIO, "I/O error");
                eErr = CE_Failure;
            }
        }

        if (GDALPamDataset::Close() != CE_None)
            eErr = CE_Failure;
    }
    return eErr;
}

/************************************************************************/
/*                          GetGeoTransform()                           */
/************************************************************************/

CPLErr PNMDataset::GetGeoTransform(GDALGeoTransform &gt) const

{
    if (bGeoTransformValid)
    {
        gt = m_gt;
        return CE_None;
    }

    return CE_Failure;
}

/************************************************************************/
/*                              Identify()                              */
/************************************************************************/

int PNMDataset::Identify(GDALOpenInfo *poOpenInfo)

{
    /* -------------------------------------------------------------------- */
    /*      Verify that this is a _raw_ ppm or pgm file.  Note, we don't    */
    /*      support ascii files, or pbm (1bit) files.                       */
    /* -------------------------------------------------------------------- */
    if (poOpenInfo->nHeaderBytes < 10 || poOpenInfo->fpL == nullptr)
        return FALSE;

    if (poOpenInfo->pabyHeader[0] != 'P' ||
        (poOpenInfo->pabyHeader[2] != ' ' &&   // XXX: Magick number
         poOpenInfo->pabyHeader[2] != '\t' &&  // may be followed
         poOpenInfo->pabyHeader[2] != '\n' &&  // any of the blank
         poOpenInfo->pabyHeader[2] != '\r'))   // characters
        return FALSE;

    if (poOpenInfo->pabyHeader[1] != '5' && poOpenInfo->pabyHeader[1] != '6')
        return FALSE;

    return TRUE;
}

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

GDALDataset *PNMDataset::Open(GDALOpenInfo *poOpenInfo)

{
    /* -------------------------------------------------------------------- */
    /*      Verify that this is a _raw_ ppm or pgm file.  Note, we don't    */
    /*      support ascii files, or pbm (1bit) files.                       */
    /* -------------------------------------------------------------------- */
    if (!Identify(poOpenInfo))
        return nullptr;

    /* -------------------------------------------------------------------- */
    /*      Parse out the tokens from the header.                           */
    /* -------------------------------------------------------------------- */
    const char *pszSrc = reinterpret_cast<char *>(poOpenInfo->pabyHeader);
    char szToken[512] = {'\0'};
    int iToken = 0;
    int nWidth = -1;
    int nHeight = -1;
    int nMaxValue = -1;

    int iIn = 2;
    while (iIn < poOpenInfo->nHeaderBytes && iToken < 3)
    {
        unsigned int iOut = 0;
        szToken[0] = '\0';
        while (iOut < sizeof(szToken) && iIn < poOpenInfo->nHeaderBytes)
        {
            if (pszSrc[iIn] == '#')
            {
                while (iIn < poOpenInfo->nHeaderBytes - 1 &&
                       pszSrc[iIn] != 10 && pszSrc[iIn] != 13)
                    iIn++;
            }

            if (iOut != 0 && isspace(static_cast<unsigned char>(pszSrc[iIn])))
            {
                szToken[iOut] = '\0';

                if (iToken == 0)
                    nWidth = atoi(szToken);
                else if (iToken == 1)
                    nHeight = atoi(szToken);
                else if (iToken == 2)
                    nMaxValue = atoi(szToken);

                iToken++;
                iIn++;
                break;
            }

            else if (!isspace(static_cast<unsigned char>(pszSrc[iIn])))
            {
                szToken[iOut++] = pszSrc[iIn];
            }

            iIn++;
        }
    }

    CPLDebug("PNM", "PNM header contains: width=%d, height=%d, maxval=%d",
             nWidth, nHeight, nMaxValue);

    if (iToken != 3 || nWidth < 1 || nHeight < 1 || nMaxValue < 1)
        return nullptr;

    /* -------------------------------------------------------------------- */
    /*      Create a corresponding GDALDataset.                             */
    /* -------------------------------------------------------------------- */
    auto poDS = std::make_unique<PNMDataset>();

    /* -------------------------------------------------------------------- */
    /*      Capture some information from the file that is of interest.     */
    /* -------------------------------------------------------------------- */
    poDS->nRasterXSize = nWidth;
    poDS->nRasterYSize = nHeight;

    // Borrow file pointer
    std::swap(poDS->fpImage, poOpenInfo->fpL);

    poDS->eAccess = poOpenInfo->eAccess;

    /* -------------------------------------------------------------------- */
    /*      Create band information objects.                                */
    /* -------------------------------------------------------------------- */

    GDALDataType eDataType = GDT_Unknown;
    if (nMaxValue < 256)
        eDataType = GDT_Byte;
    else
        eDataType = GDT_UInt16;

    const int iPixelSize = GDALGetDataTypeSizeBytes(eDataType);

    if (poOpenInfo->pabyHeader[1] == '5')
    {
        if (nWidth > INT_MAX / iPixelSize)
        {
            CPLError(CE_Failure, CPLE_AppDefined, "Int overflow occurred.");
            return nullptr;
        }
        auto poBand = RawRasterBand::Create(
            poDS.get(), 1, poDS->fpImage, iIn, iPixelSize, nWidth * iPixelSize,
            eDataType, RawRasterBand::ByteOrder::ORDER_BIG_ENDIAN,
            RawRasterBand::OwnFP::NO);
        if (!poBand)
            return nullptr;
        poBand->SetColorInterpretation(GCI_GrayIndex);
        poDS->SetBand(1, std::move(poBand));
    }
    else
    {
        if (nWidth > INT_MAX / (3 * iPixelSize))
        {
            CPLError(CE_Failure, CPLE_AppDefined, "Int overflow occurred.");
            return nullptr;
        }
        for (int i = 0; i < 3; ++i)
        {
            auto poBand = RawRasterBand::Create(
                poDS.get(), i + 1, poDS->fpImage, iIn + i * iPixelSize,
                3 * iPixelSize, nWidth * 3 * iPixelSize, eDataType,
                RawRasterBand::ByteOrder::ORDER_BIG_ENDIAN,
                RawRasterBand::OwnFP::NO);
            if (!poBand)
                return nullptr;
            poBand->SetColorInterpretation(
                static_cast<GDALColorInterp>(GCI_RedBand + i));
            poDS->SetBand(i + 1, std::move(poBand));
        }
    }

    /* -------------------------------------------------------------------- */
    /*      Check for world file.                                           */
    /* -------------------------------------------------------------------- */
    poDS->bGeoTransformValid = CPL_TO_BOOL(
        GDALReadWorldFile(poOpenInfo->pszFilename, ".wld", poDS->m_gt.data()));

    /* -------------------------------------------------------------------- */
    /*      Initialize any PAM information.                                 */
    /* -------------------------------------------------------------------- */
    poDS->SetDescription(poOpenInfo->pszFilename);
    poDS->TryLoadXML();

    /* -------------------------------------------------------------------- */
    /*      Check for overviews.                                            */
    /* -------------------------------------------------------------------- */
    poDS->oOvManager.Initialize(poDS.get(), poOpenInfo->pszFilename);

    return poDS.release();
}

/************************************************************************/
/*                               Create()                               */
/************************************************************************/

GDALDataset *PNMDataset::Create(const char *pszFilename, int nXSize, int nYSize,
                                int nBandsIn, GDALDataType eType,
                                char **papszOptions)

{
    /* -------------------------------------------------------------------- */
    /*      Verify input options.                                           */
    /* -------------------------------------------------------------------- */
    if (eType != GDT_Byte && eType != GDT_UInt16)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Attempt to create PNM dataset with an illegal "
                 "data type (%s), only Byte and UInt16 supported.",
                 GDALGetDataTypeName(eType));

        return nullptr;
    }

    if (nBandsIn != 1 && nBandsIn != 3)
    {
        CPLError(CE_Failure, CPLE_AppDefined,
                 "Attempt to create PNM dataset with an illegal number"
                 "of bands (%d).  Must be 1 (greyscale) or 3 (RGB).",
                 nBandsIn);

        return nullptr;
    }
    const CPLString osExt(CPLGetExtensionSafe(pszFilename));
    if (nBandsIn == 1)
    {
        if (!EQUAL(osExt, "PGM"))
        {
            CPLError(CE_Warning, CPLE_AppDefined,
                     "Extension for a 1-band netpbm file should be .pgm");
        }
    }
    else /* if( nBands == 3 ) */
    {
        if (!EQUAL(osExt, "PPM"))
        {
            CPLError(CE_Warning, CPLE_AppDefined,
                     "Extension for a 3-band netpbm file should be .ppm");
        }
    }

    /* -------------------------------------------------------------------- */
    /*      Try to create the file.                                         */
    /* -------------------------------------------------------------------- */
    VSILFILE *fp = VSIFOpenL(pszFilename, "wb");
    if (fp == nullptr)
    {
        CPLError(CE_Failure, CPLE_OpenFailed,
                 "Attempt to create file `%s' failed.", pszFilename);
        return nullptr;
    }

    /* -------------------------------------------------------------------- */
    /*      Write out the header.                                           */
    /* -------------------------------------------------------------------- */
    int nMaxValue = 0;

    const char *pszMaxValue = CSLFetchNameValue(papszOptions, "MAXVAL");
    if (pszMaxValue)
    {
        nMaxValue = atoi(pszMaxValue);
        if (eType == GDT_Byte && (nMaxValue > 255 || nMaxValue < 0))
            nMaxValue = 255;
        else if (nMaxValue > 65535 || nMaxValue < 0)
            nMaxValue = 65535;
    }
    else
    {
        if (eType == GDT_Byte)
            nMaxValue = 255;
        else
            nMaxValue = 65535;
    }

    char szHeader[500] = {'\0'};

    if (nBandsIn == 3)
        snprintf(szHeader, sizeof(szHeader), "P6\n%d %d\n%d\n", nXSize, nYSize,
                 nMaxValue);
    else
        snprintf(szHeader, sizeof(szHeader), "P5\n%d %d\n%d\n", nXSize, nYSize,
                 nMaxValue);

    bool bOK = VSIFWriteL(szHeader, strlen(szHeader) + 2, 1, fp) == 1;
    if (VSIFCloseL(fp) != 0)
        bOK = false;

    if (!bOK)
        return nullptr;

    GDALOpenInfo oOpenInfo(pszFilename, GA_Update);
    return Open(&oOpenInfo);
}

/************************************************************************/
/*                         GDALRegister_PNM()                           */
/************************************************************************/

void GDALRegister_PNM()

{
    if (GDALGetDriverByName("PNM") != nullptr)
        return;

    GDALDriver *poDriver = new GDALDriver();

    poDriver->SetDescription("PNM");
    poDriver->SetMetadataItem(GDAL_DCAP_RASTER, "YES");
    poDriver->SetMetadataItem(GDAL_DMD_LONGNAME,
                              "Portable Pixmap Format (netpbm)");
    poDriver->SetMetadataItem(GDAL_DMD_HELPTOPIC, "drivers/raster/pnm.html");
    // pgm : grey
    // ppm : RGB
    // pnm : ??
    poDriver->SetMetadataItem(GDAL_DMD_EXTENSIONS, "pgm ppm pnm");
    poDriver->SetMetadataItem(GDAL_DMD_MIMETYPE, "image/x-portable-anymap");
    poDriver->SetMetadataItem(GDAL_DMD_CREATIONDATATYPES, "Byte UInt16");
    poDriver->SetMetadataItem(GDAL_DMD_CREATIONOPTIONLIST,
                              "<CreationOptionList>"
                              "   <Option name='MAXVAL' type='unsigned int' "
                              "description='Maximum color value'/>"
                              "</CreationOptionList>");
    poDriver->SetMetadataItem(GDAL_DCAP_VIRTUALIO, "YES");

    poDriver->pfnOpen = PNMDataset::Open;
    poDriver->pfnCreate = PNMDataset::Create;
    poDriver->pfnIdentify = PNMDataset::Identify;

    GetGDALDriverManager()->RegisterDriver(poDriver);
}