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

   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 "imstkVTKTextureDelegate.h"
#include "imstkGeometryUtilities.h"
#include "imstkLogger.h"
#include "imstkTexture.h"

#include <vtkImageData.h>
#include <vtkImageFlip.h>
#include <vtkImageReader2Factory.h>
#include <vtkPNGReader.h>
#include <vtkTexture.h>
#include <vtksys/SystemTools.hxx>

namespace imstk
{
VTKTextureDelegate::VTKTextureDelegate(std::shared_ptr<Texture> texture) : m_vtkTexture(vtkSmartPointer<vtkTexture>::New())
{
    m_texture = texture;
    const std::string tFileName = texture->getPath();

    // If the texture is provided by ImageData use that, otherwise load via path
    std::shared_ptr<ImageData> imstkImgData = texture->getImageData();
    if (imstkImgData == nullptr)
    {
        CHECK(vtksys::SystemTools::FileExists(tFileName.c_str()))
            << "Error: texture file \"" << tFileName << "\" does not exist";

        // Load by file name
        vtkNew<vtkImageReader2Factory> readerFactory;
        if (texture->getType() == Texture::Type::Cubemap)
        {
            std::string sideNames[6] = { "posx", "negx", "posy", "negy", "posz", "negz" };
            m_vtkTexture->SetCubeMap(true);

            for (int i = 0; i < 6; i++)
            {
                auto index     = tFileName.find(".");
                auto tempName  = tFileName.substr(0, index);
                auto extension = tFileName.substr(index);
                auto sideName  = tempName + sideNames[i] + extension;

                vtkImageReader2* imgReader = readerFactory->CreateImageReader2(sideName.c_str());

                CHECK(imgReader != nullptr) << "Error: could not find reader for "
                                            << sideName;

                auto imageFlip = vtkSmartPointer<vtkImageFlip>::New();
                imageFlip->SetFilteredAxis(1);
                imgReader->SetFileName(sideName.c_str());
                imgReader->Update();
                imageFlip->SetInputConnection(imgReader->GetOutputPort());
                m_vtkTexture->SetInputConnection(i, imageFlip->GetOutputPort());
            }
        }
        else
        {
            vtkImageReader2* imgReader = readerFactory->CreateImageReader2(tFileName.c_str());

            CHECK(imgReader != nullptr) << "Error: could not find reader for "
                                        << tFileName;

            imgReader->SetFileName(tFileName.c_str());
            imgReader->Update();
            m_vtkTexture->SetBlendingMode(vtkTexture::VTK_TEXTURE_BLENDING_MODE_ADD);
            m_vtkTexture->SetRepeat(m_texture->getRepeating());
            m_vtkTexture->SetInputConnection(0, imgReader->GetOutputPort());

            if (texture->getType() == Texture::Type::Diffuse)
            {
                m_vtkTexture->SetUseSRGBColorSpace(true);
            }
        }
    }
    else
    {
        // Load by ImageData
        vtkSmartPointer<vtkImageData> vtkImgData = GeometryUtils::coupleVtkImageData(imstkImgData);
        m_vtkTexture->SetBlendingMode(vtkTexture::VTK_TEXTURE_BLENDING_MODE_ADD);
        m_vtkTexture->SetRepeat(m_texture->getRepeating());
        m_vtkTexture->SetInputData(vtkImgData);

        if (texture->getType() == Texture::Type::Diffuse)
        {
            m_vtkTexture->SetUseSRGBColorSpace(true);
        }
    }

    // Observe changes to the texture
    connect<Event>(m_texture, &Texture::modified, this, &VTKTextureDelegate::textureModified);
}

void
VTKTextureDelegate::textureModified(Event* imstkNotUsed(e))
{
    //m_vtkTexture->GetInputDataObject();
    m_vtkTexture->Modified();
}
}
