// Copyright (c) 2022 The Foundry Visionmongers Ltd. All Rights Reserved.

#include "DDImage/Knobs.h"
#include "DDImage/SourceGeomOp.h"

#include "usg/geom/MeshPrim.h"
#include "usg/geom/GeomTokens.h"

#include "ndk/geo/utils/MeshUtils.h"

#include <cassert>

using namespace DD::Image;

namespace NukeExample {
  static const char* kTriangleClass = "GeoTriangle";
  static const char* kHelp = "Creates a 3D @i;Triangle@n;";

  class GeoTriangle : public SourceGeomOp
  {
    struct KnobSample : public GeomKnobSample
    {
      fdk::Vec3f pointA;
      fdk::Vec3f pointB;
      fdk::Vec3f pointC;
    } parms;

    public:

      class Engine : public SourceEngine
      {
        KnobSample parms;

      public:
        Engine(Op* parent) : SourceEngine(parent) {}

        void createPrims(usg::GeomSceneContext& context, const usg::Path& path) override
        {
          const auto kPointA = knob("point_a");
          if (kPointA) {
            parms.pointA = kPointA.get<fdk::Vec3f>();
          }

          const auto kPointB = knob("point_b");
          if (kPointB) {
            parms.pointB = kPointB.get<fdk::Vec3f>();
          }

          const auto kPointC = knob("point_c");
          if (kPointC) {
            parms.pointC = kPointC.get<fdk::Vec3f>();
          }

          if (definesEditLayer()) {
            usg::LayerRef defineLayer = editLayer();
            assert(defineLayer);

            ndk::MeshSample sample;

            usg::MeshPrim mesh = usg::MeshPrim::defineInLayer(defineLayer, path.appendChild("Triangle"));

            sample.addTri(0, 1, 2);
            sample.points = {parms.pointA, parms.pointB, parms.pointC};

            sample.setMeshPrimFaceTopology(mesh);
            sample.setMeshPrimPointsAndBounds(mesh, true/*buildBoundsFromPoints*/);
            sample.setMeshPrimProperties(mesh, true/*setUvs*/, true/*setNormals*/);
          }
        }
      };

      GeoTriangle(Node* node) :
        SourceGeomOp(node, BuildEngine<Engine>()),
        _aPos(0, 0, 0),
        _bPos(1, 0, 0),
        _cPos(0, 1, 0)
      {}

      virtual const char* Class() const override { return kTriangleClass; }

      const char* node_help() const override { return kHelp; }

      virtual void knobs(Knob_Callback f) override {
        SourceGeomOp::knobs(f); // Set up the common SourceGeo knobs.

        XYZ_knob(f, &_aPos[0], "point_a", "a");
        KnobDefinesGeometry(f);
        XYZ_knob(f, &_bPos[0], "point_b", "b");
        KnobDefinesGeometry(f);
        XYZ_knob(f, &_cPos[0], "point_c", "c");
        KnobDefinesGeometry(f);

        makeTransformKnob(f);
      }

      static Op* Build(Node* node) { return new GeoTriangle(node); }
      static const Op::Description description;

    private:
      fdk::Vec3f _aPos;
      fdk::Vec3f _bPos;
      fdk::Vec3f _cPos;
  };

  const Op::Description GeoTriangle::description(kTriangleClass, GeoTriangle::Build);
}