// This file is part of the AliceVision project.
// Copyright (c) 2017 AliceVision contributors.
// This Source Code Form is subject to the terms of the Mozilla Public License,
// v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at https://mozilla.org/MPL/2.0/.

#include <aliceVision/cmdline/cmdline.hpp>
#include <aliceVision/system/Logger.hpp>
#include <aliceVision/system/main.hpp>
#include <aliceVision/system/Timer.hpp>
#include <aliceVision/mvsUtils/common.hpp>

#include <OpenMesh/Core/IO/reader/OBJReader.hh>
#include <OpenMesh/Core/IO/writer/OBJWriter.hh>
#include <OpenMesh/Core/IO/MeshIO.hh>
#include <OpenMesh/Core/Mesh/TriMesh_ArrayKernelT.hh>
#include <OpenMesh/Core/Geometry/VectorT.hh>
#include <OpenMesh/Tools/Decimater/DecimaterT.hh>
#include <OpenMesh/Tools/Decimater/ModQuadricT.hh>

#include <boost/program_options.hpp>

#include <filesystem>

// These constants define the current software version.
// They must be updated when the command line is changed.
#define ALICEVISION_SOFTWARE_VERSION_MAJOR 1
#define ALICEVISION_SOFTWARE_VERSION_MINOR 0

using namespace aliceVision;

namespace fs = std::filesystem;
namespace po = boost::program_options;

int aliceVision_main(int argc, char* argv[])
{
    system::Timer timer;
    std::string inputMeshPath;
    std::string outputMeshPath;

    float simplificationFactor = 0;
    int fixedNbVertices = 0;
    int minVertices = 0;
    int maxVertices = 0;
    bool flipNormals = false;

    // clang-format off
    po::options_description requiredParams("Required parameters");
    requiredParams.add_options()
        ("input,i", po::value<std::string>(&inputMeshPath)->required(),
         "Input Mesh (OBJ file format).")
        ("output,o", po::value<std::string>(&outputMeshPath)->required(),
         "Output mesh (OBJ file format).");

    po::options_description optionalParams("Optional parameters");
    optionalParams.add_options()
        ("simplificationFactor", po::value<float>(&simplificationFactor)->default_value(simplificationFactor),
         "Simplification factor.")
        ("nbVertices", po::value<int>(&fixedNbVertices)->default_value(fixedNbVertices),
         "Fixed number of output vertices.")
        ("minVertices", po::value<int>(&minVertices)->default_value(minVertices),
         "Min number of output vertices.")
        ("maxVertices", po::value<int>(&maxVertices)->default_value(maxVertices),
         "Max number of output vertices.")
        ("flipNormals", po::value<bool>(&flipNormals)->default_value(flipNormals),
         "Option to flip face normals. It can be needed as it depends on the vertices order in triangles and the "
         "convention changes from one software to another.");
    // clang-format on

    CmdLine cmdline("AliceVision meshDecimate");

    cmdline.add(requiredParams);
    cmdline.add(optionalParams);
    if (!cmdline.execute(argc, argv))
    {
        return EXIT_FAILURE;
    }

    fs::path outDirectory = fs::path(outputMeshPath).parent_path();
    if (!fs::is_directory(outDirectory))
        fs::create_directory(outDirectory);

    // Mesh type
    typedef OpenMesh::TriMesh_ArrayKernelT<> Mesh;
    // Decimater type
    typedef OpenMesh::Decimater::DecimaterT<Mesh> Decimater;
    // Decimation Module Handle type
    typedef OpenMesh::Decimater::ModQuadricT<Mesh>::Handle HModQuadric;

    Mesh mesh;
    if (!OpenMesh::IO::read_mesh(mesh, inputMeshPath))
    {
        ALICEVISION_LOG_ERROR("Unable to read input mesh from the file: " << inputMeshPath);
        return EXIT_FAILURE;
    }

    ALICEVISION_LOG_INFO("Mesh file: \"" << inputMeshPath << "\" loaded.");

    int nbInputPoints = mesh.n_vertices();
    int nbOutputPoints = 0;
    if (fixedNbVertices != 0)
    {
        nbOutputPoints = fixedNbVertices;
    }
    else
    {
        if (simplificationFactor != 0.0)
        {
            nbOutputPoints = simplificationFactor * nbInputPoints;
        }
        if (minVertices != 0)
        {
            if (nbInputPoints > minVertices && nbOutputPoints < minVertices)
                nbOutputPoints = minVertices;
        }
        if (maxVertices != 0)
        {
            if (nbInputPoints > maxVertices && nbOutputPoints > maxVertices)
                nbOutputPoints = maxVertices;
        }
    }

    ALICEVISION_LOG_INFO("Input mesh: " << nbInputPoints << " vertices and " << mesh.n_faces() << " facets.");
    ALICEVISION_LOG_INFO("Target output mesh: " << nbOutputPoints << " vertices.");

    {
        // a decimater object, connected to a mesh
        Decimater decimater(mesh);
        // use a quadric module
        HModQuadric hModQuadric;
        // register module at the decimater
        decimater.add(hModQuadric);

        // the way to access the module
        std::cout << decimater.module(hModQuadric).name() << std::endl;

        /*
         * since we need exactly one priority module (non-binary)
         * we have to call set_binary(false) for our priority module
         * in the case of HModQuadric, unset_max_err() calls set_binary(false) internally
         */
        decimater.module(hModQuadric).unset_max_err();
        // let the decimater initialize the mesh and the modules
        decimater.initialize();
        // do decimation
        size_t removedVertices = decimater.decimate_to(nbOutputPoints);
        decimater.mesh().garbage_collection();
    }
    ALICEVISION_LOG_INFO("Output mesh: " << mesh.n_vertices() << " vertices and " << mesh.n_faces() << " facets.");

    if (mesh.n_faces() == 0)
    {
        ALICEVISION_LOG_ERROR("Failed: the output mesh is empty.");
        return EXIT_FAILURE;
    }

    ALICEVISION_LOG_INFO("Save mesh.");
    // Save output mesh
    if (!OpenMesh::IO::write_mesh(mesh, outputMeshPath))
    {
        ALICEVISION_LOG_ERROR("Failed to save mesh \"" << outputMeshPath << "\".");
        return EXIT_FAILURE;
    }
    ALICEVISION_LOG_INFO("Mesh file: \"" << outputMeshPath << "\" saved.");

    ALICEVISION_LOG_INFO("Task done in (s): " + std::to_string(timer.elapsed()));
    return EXIT_SUCCESS;
}
