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

 *

 * Project:  GDAL

 * Purpose:  "nodata-to-alpha" step of "raster pipeline"

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

 *

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

 * Copyright (c) 2025, Even Rouault <even dot rouault at spatialys.com>

 *

 * SPDX-License-Identifier: MIT

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

#include "gdalalg_raster_nodata_to_alpha.h"

#include "gdal_priv.h"

#include "gdal_utils.h"

//! @cond Doxygen_Suppress

#ifndef _

#define _(x) (x)

#endif

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

/* GDALRasterNoDataToAlphaAlgorithm::GDALRasterNoDataToAlphaAlgorithm() */

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

GDALRasterNoDataToAlphaAlgorithm::GDALRasterNoDataToAlphaAlgorithm(

    bool standaloneStep)

    : GDALRasterPipelineStepAlgorithm(NAME, DESCRIPTION, HELP_URL,

                                      standaloneStep)

{

    AddArg("nodata", 0,

           _("Override nodata value of input band(s) "

             "(numeric value, 'nan', 'inf', '-inf')"),

           &m_nodata);

}

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

/*             GDALRasterNoDataToAlphaAlgorithm::RunStep()              */

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

bool GDALRasterNoDataToAlphaAlgorithm::RunStep(GDALPipelineStepRunContext &)

{

    GDALDataset *poSrcDS = m_inputDataset[0].GetDatasetRef();

    CPLAssert(poSrcDS);

    CPLAssert(m_outputDataset.GetName().empty());

    CPLAssert(!m_outputDataset.GetDatasetRef());

    if (!m_nodata.empty())

    {

        CPLStringList aosOptions;

        aosOptions.AddString("-of");

        aosOptions.AddString("VRT");

        if (m_nodata.size() == 1)

        {

            aosOptions.AddString("-a_nodata");

            aosOptions.AddString(CPLSPrintf("%.17g", m_nodata[0]));

        }

        else

        {

            if (m_nodata.size() !=

                static_cast<size_t>(poSrcDS->GetRasterCount()))

            {

                ReportError(CE_Failure, CPLE_IllegalArg,

                            "There should be %d nodata values given the input "

                            "dataset has %d bands",

                            poSrcDS->GetRasterCount(),

                            poSrcDS->GetRasterCount());

                return false;

            }

            aosOptions.AddString("-mo");

            std::string nodataValues("NODATA_VALUES=");

            for (size_t i = 0; i < m_nodata.size(); ++i)

            {

                if (i > 0)

                    nodataValues += ' ';

                nodataValues += CPLSPrintf("%.17g", m_nodata[i]);

            }

            aosOptions.AddString(nodataValues.c_str());

        }

        GDALTranslateOptions *psOptions =

            GDALTranslateOptionsNew(aosOptions.List(), nullptr);

        if (psOptions)

        {

            m_tempDS.reset(GDALDataset::FromHandle(GDALTranslate(

                "", GDALDataset::ToHandle(poSrcDS), psOptions, nullptr)));

            GDALTranslateOptionsFree(psOptions);

        }

        poSrcDS = m_tempDS.get();

    }

    bool bRet = poSrcDS != nullptr;

    if (poSrcDS)

    {

        CPLStringList aosOptions;

        aosOptions.AddString("-of");

        aosOptions.AddString("VRT");

        if (poSrcDS->GetRasterCount() > 0 &&

            poSrcDS->GetRasterBand(1)->GetMaskFlags() != GMF_ALL_VALID &&

            poSrcDS->GetRasterBand(1)->GetMaskFlags() !=

                (GMF_ALPHA | GMF_PER_DATASET))

        {

            aosOptions.AddString("-a_nodata");

            aosOptions.AddString("none");

            for (int i = 1; i <= poSrcDS->GetRasterCount(); ++i)

            {

                aosOptions.AddString("-b");

                aosOptions.AddString(CPLSPrintf("%d", i));

            }

            aosOptions.AddString("-b");

            aosOptions.AddString("mask");

            aosOptions.AddString(

                CPLSPrintf("-colorinterp_%d", poSrcDS->GetRasterCount() + 1));

            aosOptions.AddString("alpha");

        }

        std::unique_ptr<GDALDataset> poOutDS;

        GDALTranslateOptions *psOptions =

            GDALTranslateOptionsNew(aosOptions.List(), nullptr);

        if (psOptions)

        {

            poOutDS.reset(GDALDataset::FromHandle(GDALTranslate(

                "", GDALDataset::ToHandle(poSrcDS), psOptions, nullptr)));

            GDALTranslateOptionsFree(psOptions);

            poOutDS->GetRasterBand(1)->GetMaskFlags();

        }

        bRet = poOutDS != nullptr;

        if (poOutDS)

        {

            m_outputDataset.Set(std::move(poOutDS));

        }

    }

    return bRet;

}

GDALRasterNoDataToAlphaAlgorithmStandalone::

    ~GDALRasterNoDataToAlphaAlgorithmStandalone() = default;

//! @endcond