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

 *

 * Project:  GDAL

 * Purpose:  "scale" 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_scale.h"

#include "gdal_priv.h"

#include "gdal_utils.h"

#include <cmath>

//! @cond Doxygen_Suppress

#ifndef _

#define _(x) (x)

#endif

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

/*         GDALRasterScaleAlgorithm::GDALRasterScaleAlgorithm()         */

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

GDALRasterScaleAlgorithm::GDALRasterScaleAlgorithm(bool standaloneStep)

    : GDALRasterPipelineStepAlgorithm(NAME, DESCRIPTION, HELP_URL,

                                      standaloneStep)

{

    AddOutputDataTypeArg(&m_type);

    AddBandArg(&m_band,

               _("Select band to restrict the scaling (1-based index)"));

    AddArg("src-min", 0, _("Minimum value of the source range"), &m_srcMin);

    AddArg("src-max", 0, _("Maximum value of the source range"), &m_srcMax);

    AddArg("dst-min", 0, _("Minimum value of the destination range"),

           &m_dstMin);

    AddArg("dst-max", 0, _("Maximum value of the destination range"),

           &m_dstMax);

    AddArg("exponent", 0,

           _("Exponent to apply non-linear scaling with a power function"),

           &m_exponent);

    AddArg("no-clip", 0, _("Do not clip input values to [srcmin, srcmax]"),

           &m_noClip);

}

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

/*                 GDALRasterScaleAlgorithm::RunStep()                  */

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

bool GDALRasterScaleAlgorithm::RunStep(GDALPipelineStepRunContext &)

{

    auto poSrcDS = m_inputDataset[0].GetDatasetRef();

    CPLAssert(poSrcDS);

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

    CPLAssert(!m_outputDataset.GetDatasetRef());

    CPLStringList aosOptions;

    aosOptions.AddString("-of");

    aosOptions.AddString("VRT");

    if (!m_type.empty())

    {

        aosOptions.AddString("-ot");

        aosOptions.AddString(m_type.c_str());

    }

    aosOptions.AddString(m_band > 0 ? CPLSPrintf("-scale_%d", m_band)

                                    : "-scale");

    if (!std::isnan(m_srcMin))

    {

        if (std::isnan(m_srcMax))

        {

            ReportError(CE_Failure, CPLE_AppDefined,

                        "src-max must be specified when src-min is specified");

            return false;

        }

        aosOptions.AddString(CPLSPrintf("%.17g", m_srcMin));

        aosOptions.AddString(CPLSPrintf("%.17g", m_srcMax));

    }

    else if (!std::isnan(m_srcMax))

    {

        ReportError(CE_Failure, CPLE_AppDefined,

                    "src-min must be specified when src-max is specified");

        return false;

    }

    if (!std::isnan(m_dstMin))

    {

        if (std::isnan(m_dstMax))

        {

            ReportError(CE_Failure, CPLE_AppDefined,

                        "dst-max must be specified when dst-min is specified");

            return false;

        }

        if (std::isnan(m_srcMin))

        {

            aosOptions.AddString("NaN");

            aosOptions.AddString("NaN");

        }

        aosOptions.AddString(CPLSPrintf("%.17g", m_dstMin));

        aosOptions.AddString(CPLSPrintf("%.17g", m_dstMax));

    }

    else if (!std::isnan(m_dstMax))

    {

        ReportError(CE_Failure, CPLE_AppDefined,

                    "dst-min must be specified when dst-max is specified");

        return false;

    }

    if (!std::isnan(m_exponent))

    {

        aosOptions.AddString(m_band > 0 ? CPLSPrintf("-exponent_%d", m_band)

                                        : "-exponent");

        aosOptions.AddString(CPLSPrintf("%.17g", m_exponent));

    }

    else if (!m_noClip)

    {

        aosOptions.AddString(m_band > 0 ? CPLSPrintf("-exponent_%d", m_band)

                                        : "-exponent");

        aosOptions.AddString("1");

    }

    if (m_noClip)

    {

        aosOptions.AddString("--no-clip");

    }

    GDALTranslateOptions *psOptions =

        GDALTranslateOptionsNew(aosOptions.List(), nullptr);

    auto poOutDS = std::unique_ptr<GDALDataset>(GDALDataset::FromHandle(

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

    GDALTranslateOptionsFree(psOptions);

    const bool bRet = poOutDS != nullptr;

    if (poOutDS)

    {

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

    }

    return bRet;

}

GDALRasterScaleAlgorithmStandalone::~GDALRasterScaleAlgorithmStandalone() =

    default;

//! @endcond