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

 *

 * Project:  GDAL

 * Purpose:  "blend" 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

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

#ifndef GDALALG_RASTER_BLEND_INCLUDED

#define GDALALG_RASTER_BLEND_INCLUDED

#include "gdalrasterpipelinestepalgorithm.h"

#include "gdal_dataset.h"

//! @cond Doxygen_Suppress

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

/*                           CompositionMode                            */

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

//! Blend composition modes (aka: operators)

enum class CompositionMode : unsigned

{

    SRC_OVER = 0,

    HSV_VALUE,

    MULTIPLY,

    SCREEN,

    OVERLAY,

    HARD_LIGHT,

    DARKEN,

    LIGHTEN,

    COLOR_DODGE,

    COLOR_BURN,

};

//! Returns a map of all composition modes to their string identifiers

std::map<CompositionMode, std::string> CompositionModes();

//! Returns the text identifier of the composition mode

std::string CompositionModeToString(CompositionMode mode);

//! Returns a list of all modes string identifiers

std::vector<std::string> CompositionModesIdentifiers();

//! Parses a composition mode from its string identifier

CompositionMode CompositionModeFromString(const std::string &str);

//! Returns the minimum number of bands required for the given composition mode

int MinBandCountForCompositionMode(CompositionMode mode);

/**

 *  Returns the maximum number of bands allowed for the given composition mode

 *  (-1 means no limit)

 */

int MaxBandCountForCompositionMode(CompositionMode mode);

//! Checks whether the number of bands is compatible with the given composition mode

bool BandCountIsCompatibleWithCompositionMode(int bandCount,

                                              CompositionMode mode);

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

/*                       GDALRasterBlendAlgorithm                       */

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

class GDALRasterBlendAlgorithm /* non final*/

    : public GDALRasterPipelineStepAlgorithm

{

  public:

    explicit GDALRasterBlendAlgorithm(bool standaloneStep = false);

    static constexpr const char *NAME = "blend";

    static constexpr const char *DESCRIPTION =

        "Blend/compose two raster datasets";

    static constexpr const char *HELP_URL = "/programs/gdal_raster_blend.html";

  private:

    bool RunStep(GDALPipelineStepRunContext &ctxt) override;

    bool ValidateGlobal();

    GDALArgDatasetValue m_overlayDataset{};

    CompositionMode m_operator{};

    std::string m_operatorIdentifier{};

    static constexpr int OPACITY_INPUT_RANGE = 100;

    int m_opacity = OPACITY_INPUT_RANGE;

    std::unique_ptr<GDALDataset, GDALDatasetUniquePtrReleaser> m_poTmpSrcDS{};

    std::unique_ptr<GDALDataset, GDALDatasetUniquePtrReleaser>

        m_poTmpOverlayDS{};

};

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

/*                  GDALRasterBlendAlgorithmStandalone                  */

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

class GDALRasterBlendAlgorithmStandalone final : public GDALRasterBlendAlgorithm

{

  public:

    GDALRasterBlendAlgorithmStandalone()

        : GDALRasterBlendAlgorithm(/* standaloneStep = */ true)

    {

    }

    ~GDALRasterBlendAlgorithmStandalone() override;

};

//! @endcond

#endif /* GDALALG_RASTER_COLOR_MERGE_INCLUDED */