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

 *

 * Project:  GDAL

 * Purpose:  "gdal vector concave-hull"

 * Author:   Daniel Baston

 *

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

 * Copyright (c) 2026, ISciences LLC

 *

 * SPDX-License-Identifier: MIT

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

#include "gdalalg_vector_concave_hull.h"

#include "gdal_priv.h"

#include "ogrsf_frmts.h"

#include <cinttypes>

//! @cond Doxygen_Suppress

#ifndef _

#define _(x) (x)

#endif

GDALVectorConcaveHullAlgorithm::GDALVectorConcaveHullAlgorithm(

    bool standaloneStep)

    : GDALVectorGeomAbstractAlgorithm(NAME, DESCRIPTION, HELP_URL,

                                      standaloneStep, m_opts)

{

    AddArg("ratio", 0, _("Ratio controlling the concavity"), &m_opts.m_ratio)

        .SetRequired()

        .SetMinValueIncluded(0)

        .SetMaxValueIncluded(1);

    AddArg("allow-holes", 0, _("Allow holes in the output polygon"),

           &m_opts.m_allowHoles)

        .SetDefault(false);

    AddArg("tight", 0,

           _("Whether the hull must follow the outer boundaries of the input "

             "polygons"),

           &m_opts.m_tight)

        .SetDefault(false);

}

#ifdef HAVE_GEOS

namespace

{

class GDALVectorConcaveHullAlgorithmLayer final

    : public GDALVectorGeomOneToOneAlgorithmLayer<

          GDALVectorConcaveHullAlgorithm>

{

  public:

    GDALVectorConcaveHullAlgorithmLayer(

        OGRLayer &oSrcLayer,

        const GDALVectorConcaveHullAlgorithm::Options &opts)

        : GDALVectorGeomOneToOneAlgorithmLayer<GDALVectorConcaveHullAlgorithm>(

              oSrcLayer, opts),

          m_poFeatureDefn(oSrcLayer.GetLayerDefn()->Clone())

    {

        m_poFeatureDefn->Reference();

        // Concave hull output type can vary; advertise unknown to avoid schema conflicts.

        // In polygon/multipolygoon mode, preserve input type

        for (int i = 0; i < m_poFeatureDefn->GetGeomFieldCount(); ++i)

        {

            if (IsSelectedGeomField(i))

            {

                const auto eType =

                    m_poFeatureDefn->GetGeomFieldDefn(i)->GetType();

                if (eType != wkbPolygon && eType != wkbMultiPolygon)

                    m_poFeatureDefn->GetGeomFieldDefn(i)->SetType(wkbUnknown);

            }

        }

    }

    ~GDALVectorConcaveHullAlgorithmLayer() override

    {

        m_poFeatureDefn->Release();

    }

    const OGRFeatureDefn *GetLayerDefn() const override

    {

        return m_poFeatureDefn;

    }

  protected:

    using GDALVectorGeomOneToOneAlgorithmLayer::TranslateFeature;

    std::unique_ptr<OGRFeature>

    TranslateFeature(std::unique_ptr<OGRFeature> poSrcFeature) const override

    {

        const int nGeomFieldCount = poSrcFeature->GetGeomFieldCount();

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

        {

            if (!IsSelectedGeomField(i))

                continue;

            if (const OGRGeometry *poGeom = poSrcFeature->GetGeomFieldRef(i))

            {

                const auto eType = wkbFlatten(poGeom->getGeometryType());

                std::unique_ptr<OGRGeometry> poHull(

                    (eType == wkbPolygon || eType == wkbMultiPolygon)

                        ? poGeom->ConcaveHullOfPolygons(m_opts.m_ratio,

                                                        m_opts.m_tight,

                                                        m_opts.m_allowHoles)

                        : poGeom->ConcaveHull(m_opts.m_ratio,

                                              m_opts.m_allowHoles));

                if (!poHull)

                {

                    CPLError(

                        CE_Failure, CPLE_AppDefined,

                        "Failed to compute concave hull of feature %" PRId64,

                        static_cast<int64_t>(poSrcFeature->GetFID()));

                    return nullptr;

                }

                const auto eLayerGeomType =

                    m_poFeatureDefn->GetGeomFieldDefn(i)->GetType();

                if (eLayerGeomType == wkbPolygon)

                {

                    poHull.reset(

                        OGRGeometryFactory::forceToPolygon(poHull.release()));

                }

                else if (eLayerGeomType == wkbMultiPolygon)

                {

                    poHull.reset(OGRGeometryFactory::forceToMultiPolygon(

                        poHull.release()));

                }

                poHull->assignSpatialReference(poGeom->getSpatialReference());

                poSrcFeature->SetGeomField(i, std::move(poHull));

            }

        }

        poSrcFeature->SetFDefnUnsafe(m_poFeatureDefn);

        return poSrcFeature;

    }

  private:

    OGRFeatureDefn *const m_poFeatureDefn;

    CPL_DISALLOW_COPY_ASSIGN(GDALVectorConcaveHullAlgorithmLayer)

};

}  // namespace

#endif  // HAVE_GEOS

std::unique_ptr<OGRLayerWithTranslateFeature>

GDALVectorConcaveHullAlgorithm::CreateAlgLayer(

    [[maybe_unused]] OGRLayer &srcLayer)

{

#ifdef HAVE_GEOS

    return std::make_unique<GDALVectorConcaveHullAlgorithmLayer>(srcLayer,

                                                                 m_opts);

#else

    CPLAssert(false);

    return nullptr;

#endif

}

bool GDALVectorConcaveHullAlgorithm::RunStep(GDALPipelineStepRunContext &ctxt)

{

#ifdef HAVE_GEOS

    return GDALVectorGeomAbstractAlgorithm::RunStep(ctxt);

#else

    (void)ctxt;

    ReportError(CE_Failure, CPLE_NotSupported,

                "This algorithm is only supported for builds against GEOS");

    return false;

#endif

}

GDALVectorConcaveHullAlgorithmStandalone::

    ~GDALVectorConcaveHullAlgorithmStandalone() = default;

//! @endcond