// You can get the bus .ply and .exr files from here:
// https://drive.google.com/open?id=1BLqq6HtNvQRSV_u6sCqptbX8Vx9i_k-d

#include <iostream>
#include <fstream>
#include <string>
#include <regex>
#include <cstdlib>
#include <opencv2/opencv.hpp>

using namespace std;
using namespace cv;

int linear_function()
{
  static int i = 0;
  return i+=30;
}


/*
  1) Open the param.pbrt file
  2) Create an empty replaced.pbrt file
  2) Find all occurences of {{param1}} and replace it with the "replace" string
  3) Save the edited file as replaced.pbrt
*/


void populate_pbrt_file(string search, string replace)
{
  ofstream outFile;
  ifstream readFile;
  string readout;
  size_t found;
  outFile.open("replaced.pbrt");
  readFile.open("param.pbrt");
  cout<<replace<<endl;
  while(getline(readFile,readout)){
    found = readout.find(search.c_str());
    if (readout.find(search) != string::npos) {
      readout = readout.replace(readout.find(search),search.length(),replace);
    }
    outFile << readout << endl;
  }
  outFile.close();
  readFile.close();
}

int main(){
  string replace;
  Mat image;
  int frame_width = 200; // should be the same as "integer xresolution" in the pbrt file
  int frame_height = 200; // should be the same as "integer yresolution" in the pbrt file


  string search="{{param1}}";
  vector<int> y(12);
  generate(y.begin(), y.end(), linear_function);

  VideoWriter video("video.avi",VideoWriter::fourcc('M','J','P','G'),10, Size(frame_width,frame_height));

  for (int i=0; i<y.size(); i++) {
    replace=to_string(y[i]);
    populate_pbrt_file(search, replace);     // TO DO: Implement
    system("pbrt replaced.pbrt");            // Run pbrt from the C++ program
    image = imread("temp.png");              // Load the generated image
    imwrite( to_string(i)+".jpg", image );   // Write the image out for debugging purposes
    video.write(image);                      // Write the video with the current frame
  }
  video.release();
}