#include <iostream>
#include <fcntl.h>
#include <vector>
#include <unistd.h>

using namespace std;

const int XDIM{1000};
const int YDIM{400};

using ColorT = unsigned char;

struct PixelT {
    ColorT color[3];
};

using ImageT = vector <vector <PixelT>>;

void WriteImage(string  baseFileName, const ImageT &  image);

int main() {
        vector<vector<PixelT>> image(XDIM,vector<PixelT>(YDIM));

        for(int i = 0; i < XDIM; ++i) {
           for(int j = 0; j < YDIM; ++j) {
               for(int k =0; k < 3; ++k) {
                   image[i][j].color[k] = rand()%255;
               }
           }
        }

        WriteImage("foo", image);
        return 0;
}

void WriteImage(string  baseFileName, const ImageT &  image){

    string pngName {baseFileName + ".ppm"};

    // open a file for writing
    int flags = O_CREAT | O_WRONLY | O_TRUNC;
    int mode {S_IRUSR | S_IRGRP | S_IROTH | S_IWUSR};
    int fd {open(pngName.c_str(), flags, mode)};

    if (-1 == fd) {
       perror("Error Open:");
    }

    string tmp;
    tmp = "P6\n";

    // write the PBM header
    // the magic number P6  (in ascii) followed by a newline 
    write(fd, tmp.c_str(), sizeof(char) * tmp.size());

    // width space height newline in ascii
    tmp = to_string(image.size()) + " " + to_string(image[0].size()) + "\n";
    write(fd, tmp.c_str(), sizeof(char) * tmp.size());

    // the maximum value (255) newline in ascii
    tmp = "255\n";
    write(fd, tmp.c_str(), sizeof(char) * tmp.size());


    // write the rgb values row by row in binary format
    for(int i = 0; i < image.size(); ++i) {
       for(int j = 0; j < image[0].size(); ++j) {
           write(fd, image[i][j].color, sizeof(ColorT) * 3);
       }
    }

    // close the file
    close(fd);
    // run ppmtogif or ppmtojpeg 
    string jpegName{baseFileName + ".jpeg"};
    string cmd { "ppmtojpeg  < " + pngName  + " > " + jpegName};
    system(cmd.c_str());
    unlink(pngName.c_str());
}