/* ***********************************************************************
//
//   Copyright (C) 2025 -- The 4D-STAR Collaboration
//   File Author: Emily Boudreaux
//   Last Modified: February 16, 2025
//
//   4DSSE is free software; you can use it and/or modify
//   it under the terms and restrictions the GNU General Library Public
//   License version 3 (GPLv3) as published by the Free Software Foundation.
//
//   4DSSE is distributed in the hope that it will be useful,
//   but WITHOUT ANY WARRANTY; without even the implied warranty of
//   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
//   See the GNU Library General Public License for more details.
//
//   You should have received a copy of the GNU Library General Public License
//   along with this software; if not, write to the Free Software
//   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
//
// *********************************************************************** */
#include "mfem.hpp"
#include <string>
#include <iostream>
#include <fstream>
#include <stdexcept>

#include "meshIO.h"


MeshIO::MeshIO(const std::string &mesh_file, double scale_factor)
{
    mesh_file_ = mesh_file;
    std::ifstream mesh_stream(mesh_file);
    if (!mesh_stream)
    {
        throw std::runtime_error("Mesh file not found: " + mesh_file);
        loaded_ = false;
    }
    else
    {
        mesh_ = mfem::Mesh(mesh_stream, 1, 10);
        loaded_ = true;
        if (scale_factor != 1.0) { LinearRescale(scale_factor); }
    }
}

MeshIO::~MeshIO()
{
}

void MeshIO::LinearRescale(double scale_factor) {
    if (!loaded_) {
        throw std::runtime_error("Mesh not loaded before rescaling.");
    }

    if (scale_factor <= 0.0) {
        throw std::invalid_argument("Scale factor must be positive.");
    }

    // Ensure there are nodes even for linear order meshes
    mesh_.EnsureNodes();
    const mfem::GridFunction *nodes = mesh_.GetNodes();
    double *node_data = nodes->GetData();  // THIS IS KEY

    int data_size = nodes->Size();

    for (int i = 0; i < data_size; ++i) {
        node_data[i] *= scale_factor;
    }

    // nodes->Update(); /updates the fespace
    mesh_.NodesUpdated();
 

}

bool MeshIO::IsLoaded() const
{
    return loaded_;
}

mfem::Mesh& MeshIO::GetMesh()
{
    return mesh_;
}