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

   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.

=========================================================================*/
#pragma once

#include "imstkGeometryAlgorithm.h"
#include "imstkMath.h"

#include <list>
#include <unordered_set>

namespace imstk
{
class ImageData;
class SurfaceMesh;

///
/// \class LocalMarchingCubes
///
/// \brief This filter extracts a contour SurfaceMesh from an image given an
/// isovalue. Users should prefer imstkFlyingEdges over this unless sparse/local
/// processing is needed
///
/// One can provide this filter with a list of voxels that were modified in
/// the image and it will locally update it such that little processing is done
///
/// It works in chunks, so a set of SurfaceMesh's are the output. One can provide
/// the filter with the number of divisions on each axes to split up the image
///
class LocalMarchingCubes : public GeometryAlgorithm
{
public:
    LocalMarchingCubes();
    virtual ~LocalMarchingCubes() override = default;

public:
    std::shared_ptr<SurfaceMesh> getOutputMesh(const int i) const;

    void setInputImage(std::shared_ptr<ImageData> inputImage);

    ///
    /// \brief Value where the boundary lies
    ///
    void setIsoValue(double isovalue) { m_isoValue = isovalue; }

    ///
    /// \brief Set all voxels as modified (used initially)
    ///
    void setAllModified(bool val) { m_allModified = val; }

    ///
    /// \brief Set a voxel that was modified in the image (the neighboring dual
    /// voxels will be updated on the next request)
    ///
    void setModified(const Vec3i& coord);

    ///
    /// \brief Clear all pending modifications
    ///
    void clearModified() { m_modifiedVoxels.clear(); }

    ///
    /// \brief Set the number of chunks.
    /// one minus the dimensions of image must be divisible by numChunks
    /// ((dimensionX - 1) / numChunks must have no remainder)
    /// If it doesn't the *next* divisor will be used, warning thrown
    ///
    void setNumberOfChunks(const Vec3i& numChunks);

    const Vec3i& getNumberOfChunks() const { return m_numChunks; }

protected:
    void requestUpdate() override;

private:
    // Id + coordinate of the modified voxels
    std::unordered_map<int, Vec3i> m_modifiedVoxels;   // Id + coordinate

    bool m_allModified = true;

    double m_isoValue = 0.0;

    Vec3i  m_numChunks  = Vec3i(0, 0, 0); // Number of chunks along x, y, z
    size_t m_chunkCount = 0;              ///> Total chunk count x * y * z
};
}