/*=========================================================================

   Library: iMSTK

   Copyright (c) Kitware, Inc. & Center for Modeling, Simulation,
   & Imaging in Medicine, Rensselaer Polytechnic Institute.

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0.txt

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

=========================================================================*/

#include "imstkCamera.h"
#include "imstkKeyboardSceneControl.h"
#include "imstkLight.h"
#include "imstkLogger.h"
#include "imstkMouseSceneControl.h"
#include "imstkNew.h"
#include "imstkPbdModel.h"
#include "imstkPbdObject.h"
#include "imstkRenderMaterial.h"
#include "imstkScene.h"
#include "imstkSceneManager.h"
#include "imstkSurfaceMesh.h"
#include "imstkVisualModel.h"
#include "imstkVTKViewer.h"

using namespace imstk;

// Parameters to play with
const double width  = 10.0;
const double height = 10.0;
const int    nRows  = 16;
const int    nCols  = 16;

///
/// \brief Creates cloth geometry
///
static std::shared_ptr<SurfaceMesh>
makeClothGeometry(const double width,
                  const double height,
                  const int    nRows,
                  const int    nCols)
{
    imstkNew<SurfaceMesh> clothMesh;

    StdVectorOfVec3d vertList;
    vertList.resize(nRows * nCols);
    const double dy = width / (double)(nCols - 1);
    const double dx = height / (double)(nRows - 1);
    for (int i = 0; i < nRows; ++i)
    {
        for (int j = 0; j < nCols; j++)
        {
            vertList[i * nCols + j] = Vec3d((double)dx * i, 1.0, (double)dy * j);
        }
    }
    clothMesh->setInitialVertexPositions(vertList);
    clothMesh->setVertexPositions(vertList);

    // Add connectivity data
    std::vector<SurfaceMesh::TriangleArray> triangles;
    for (std::size_t i = 0; i < nRows - 1; ++i)
    {
        for (std::size_t j = 0; j < nCols - 1; j++)
        {
            SurfaceMesh::TriangleArray tri[2];
            const size_t               index1 = i * nCols + j;
            const size_t               index2 = index1 + nCols;
            const size_t               index3 = index1 + 1;
            const size_t               index4 = index2 + 1;

            // Interleave [/][\]
            if (i % 2 ^ j % 2)
            {
                tri[0] = { { index1, index2, index3 } };
                tri[1] = { { index4, index3, index2 } };
            }
            else
            {
                tri[0] = { { index2, index4, index1 } };
                tri[1] = { { index4, index3, index1 } };
            }
            triangles.push_back(tri[0]);
            triangles.push_back(tri[1]);
        }
    }

    clothMesh->setTrianglesVertices(triangles);

    return clothMesh;
}

///
/// \brief Creates cloth object
///
static std::shared_ptr<PbdObject>
makeClothObj(const std::string& name,
             const double       width,
             const double       height,
             const int          nRows,
             const int          nCols)
{
    imstkNew<PbdObject> clothObj(name);

    // Setup the Geometry
    std::shared_ptr<SurfaceMesh> clothMesh(makeClothGeometry(width, height, nRows, nCols));

    // Setup the Parameters
    imstkNew<PBDModelConfig> pbdParams;
    pbdParams->enableConstraint(PbdConstraint::Type::Distance, 1.0e2);
    pbdParams->enableConstraint(PbdConstraint::Type::Dihedral, 1.0e1);
    pbdParams->m_fixedNodeIds     = { 0, static_cast<size_t>(nCols) - 1 };
    pbdParams->m_uniformMassValue = width * height / ((double)nRows * (double)nCols);
    pbdParams->m_gravity    = Vec3d(0.0, -9.8, 0.0);
    pbdParams->m_defaultDt  = 0.005;
    pbdParams->m_iterations = 5;

    // Setup the Model
    imstkNew<PbdModel> pbdModel;
    pbdModel->setModelGeometry(clothMesh);
    pbdModel->configure(pbdParams);

    // Setup the VisualModel
    imstkNew<RenderMaterial> material;
    material->setBackFaceCulling(false);
    material->setDisplayMode(RenderMaterial::DisplayMode::WireframeSurface);

    imstkNew<VisualModel> visualModel(clothMesh);
    visualModel->setRenderMaterial(material);

    // Setup the Object
    clothObj->addVisualModel(visualModel);
    clothObj->setPhysicsGeometry(clothMesh);
    clothObj->setDynamicalModel(pbdModel);

    return clothObj;
}

///
/// \brief This example demonstrates the cloth simulation
/// using Position based dynamics
///
int
main()
{
    // Write log to stdout and file
    Logger::startLogger();

    // Setup a scene
    imstkNew<Scene> scene("PBDCloth");
    {
        std::shared_ptr<PbdObject> clothObj = makeClothObj("Cloth", width, height, nRows, nCols);
        scene->addSceneObject(clothObj);

        // Light (white)
        imstkNew<DirectionalLight> whiteLight("whiteLight");
        whiteLight->setFocalPoint(Vec3d(5.0, -8.0, -5.0));
        whiteLight->setIntensity(1.0);
        scene->addLight(whiteLight);

        // Light (red)
        imstkNew<SpotLight> colorLight("colorLight");
        colorLight->setPosition(Vec3d(-5.0, -3.0, 5.0));
        colorLight->setFocalPoint(Vec3d(0.0, -5.0, 5.0));
        colorLight->setIntensity(100.);
        colorLight->setColor(Color::Red);
        colorLight->setSpotAngle(30.0);
        scene->addLight(colorLight);

        // Adjust camera
        scene->getActiveCamera()->setFocalPoint(0.0, -5.0, 5.0);
        scene->getActiveCamera()->setPosition(-15.0, -5.0, 25.0);
    }

    // Run the simulation
    {
        // Setup a viewer to render in its own thread
        imstkNew<VTKViewer> viewer("Viewer");
        viewer->setActiveScene(scene);

        // Setup a scene manager to advance the scene in its own thread
        imstkNew<SceneManager> sceneManager("Scene Manager");
        sceneManager->setActiveScene(scene);
        viewer->addChildThread(sceneManager); // SceneManager will start/stop with viewer

        // Add mouse and keyboard controls to the viewer
        {
            imstkNew<MouseSceneControl> mouseControl(viewer->getMouseDevice());
            mouseControl->setSceneManager(sceneManager);
            viewer->addControl(mouseControl);

            imstkNew<KeyboardSceneControl> keyControl(viewer->getKeyboardDevice());
            keyControl->setSceneManager(sceneManager);
            keyControl->setViewer(viewer);
            viewer->addControl(keyControl);
        }

        // Start viewer running, scene as paused
        sceneManager->requestStatus(ThreadStatus::Paused);
        viewer->start();
    }

    return 0;
}
