#include "OutputSurfMesh.h"
#include <fstream>
#include <stdexcept>
#include <cmath>
#include <filesystem>
#include "vtr.h"
#include <omp.h>  // include this if not already

void OutputSurfMesh::readFromFile(const std::string& filename) 
{

    std::ifstream infile(filename);
    if (!infile.is_open()) 
    {
      std::cerr << "[ERROR] Could not open: " << filename << "\n";
      throw std::runtime_error("Failed to open file: " + filename);
    }

    infile >> scale >> num_nodes;

    xyznode.resize(3, std::vector<double>(num_nodes));
    for (int i = 0; i < num_nodes; ++i) {
        double x, y, z;
        infile >> x >> y >> z;
        xyznode[0][i] = x * scale;
        xyznode[1][i] = y * scale;
        xyznode[2][i] = z * scale;
    }

    std::string dummy;
    std::getline(infile, dummy); // consume leftover newline

    infile >> num_triangles;
    triangles.resize(3, std::vector<int>(num_triangles));
    for (int i = 0; i < num_triangles; ++i) {
        int n0, n1, n2;
        infile >> n0 >> n1 >> n2;
        triangles[0][i] = n0;
        triangles[1][i] = n1;
        triangles[2][i] = n2;
    }

    infile.close();
}



void OutputSurfMesh::printSummary() const {
    std::cout << "-------- Summary --------- " << "\n";
    std::cout << "Scale: " << scale << "\n";
    std::cout << "Number of Nodes: " << num_nodes << "\n";
    std::cout << "Number of Triangles: " << num_triangles << "\n";
    std::cout << "First Triangle: " << triangles[0][0] << "," << triangles[1][0] << "," << triangles[2][0] << "\n";    
    std::cout << "Last Triangle: " << triangles[0][num_triangles-1] << "," << triangles[1][num_triangles-1] << "," << triangles[2][num_triangles-1] << "\n";    
}

const std::vector<double>& OutputSurfMesh::getNode(int idx) const {
    static std::vector<double> node(3);
    node[0] = xyznode[0][idx];
    node[1] = xyznode[1][idx];
    node[2] = xyznode[2][idx];
    return node;
}

std::vector<int> OutputSurfMesh::getTriangle(int idx) const {
    return {triangles[0][idx], triangles[1][idx], triangles[2][idx]};
}

std::vector<double> OutputSurfMesh::getNormal(int idx) const {
    return {normals[idx][0], normals[idx][1], normals[idx][2]};
}

void OutputSurfMesh::computeTriangleNormals() 
{
    normals.resize(num_triangles, std::vector<double>(3, 0.0));

    #pragma omp parallel for schedule(static)
    for (int i = 0; i < num_triangles; ++i) 
    {
        int n0 = triangles[0][i];
        int n1 = triangles[1][i];
        int n2 = triangles[2][i];

        // Get coordinates of the triangle nodes
        vtr node0(xyznode[0][n0],xyznode[1][n0],xyznode[2][n0]); 
        vtr node1(xyznode[0][n1],xyznode[1][n1],xyznode[2][n1]); 
        vtr node2(xyznode[0][n2],xyznode[1][n2],xyznode[2][n2]); 

        vtr lvtr0 = node1 - node0;
        vtr lvtr1 = node2 - node0;
        vtr normal = lvtr0 * lvtr1;
        normal.unitvtr();

        normals[i][0] = normal.getx();
        normals[i][1] = normal.gety();
        normals[i][2] = normal.getz();
    }
}