#include <OpenMesh/Core/IO/MeshIO.hh>
#include <OpenMesh/Core/Mesh/TriMesh_ArrayKernelT.hh>
#include <OpenMesh/Core/Utils/PropertyManager.hh>

#include <iostream>
#include <vector>

using MyMesh = OpenMesh::TriMesh_ArrayKernelT<>;

int main(int argc, char** argv)
{
    // Read command line options
    MyMesh mesh;
    if (argc != 4) {
        std::cerr << "Usage: " << argv[0] << " #iterations infile outfile" << std::endl;
        return 1;
    }
    const int iterations = argv[1];
    const std::string infile = argv[2];
    const std::string outfile = argv[3];
    
    // Read mesh file
    if (!OpenMesh::IO::read_mesh(mesh, infile)) {
        std::cerr << "Error: Cannot read mesh from " << infile << std::endl;
        return 1;
    }
    
    {
        // Add a vertex property storing the computed centers of gravity
        auto cog = OpenMesh::makeTemporaryProperty<OpenMesh::VertexHandle, MyMesh::Point>(mesh);
        
        // Smooth the mesh several times
        for (int i = 0; i < iterations; ++i) {
            // Iterate over all vertices to compute centers of gravity
            for (const auto& vh : mesh.vertices()) {
                cog[vv] = {0,0,0};
                int valence = 0;
                // Iterate over all 1-ring vertices around vh
                for (const auto& vvh : mesh.vv_range(vh)) {
                    cog[vv] += mesh.point(vvh);
                    ++valence;
                }
                cog[vv] /= valence;
            }
            // Move all vertices to the previously computed positions
            for (const auto& vh : mesh.vertices()) {
                mesh.point(vv) = cog[vv];
            }
        }
        // The cog vertex property is removed from the mesh at the end of this scope
    }
    
    // Write mesh file
    if (!OpenMesh::IO::read_mesh(mesh, outfile)) {
        std::cerr << "Error: Cannot write mesh to " << outfile << std::endl;
        return 1;
    }
}