#include <sstream>
#include <iostream>
#include <unistd.h>
#include <sys/ioctl.h>
#include <signal.h>
#include <fcntl.h>
#include <termios.h>

static int done = 0;      //State variable

namespace con {
    int comax() {         //Get number of columns
        struct winsize w;
        ioctl(0, TIOCGWINSZ, &w);
        return(w.ws_col);
    }

    int romax() {         //Get number of rows
        struct winsize w;
        ioctl(0, TIOCGWINSZ, &w);
        return(w.ws_row);
    }

    std::ostream& ED(std::ostream& s) {     //Clearing terminal window
        return s << std::string("\033[2J");
    }

    class estream {
        private:
            std::string escape;
        public:
            estream(std::string e): escape(e) {}
            friend std::ostream& operator<<(std::ostream&, estream);
    };

    std::ostream& operator<<(std::ostream& out, estream e) {
        out << e.escape << std::flush;
        return out;
    }

    estream CUP(int x, int y) {     //Move the cursor
        std::ostringstream sout;
        sout << "\033[" << x << ";" << y << "H";
        return(estream(sout.str()));
    }

    estream SGR(int r) {            //Background drawing
        std::ostringstream sout;
        sout << "\033[" << r << "m";
        return(estream(sout.str()));
    }

    int kbin() {        //Set delay and non-blocking mode
        char buf[2];
        int n = 0;
        int flags = fcntl(0, F_GETFL);
        fcntl(0, F_SETFL, flags | O_NONBLOCK);
        n = read(0, buf, 2);
        usleep(10000);
        fcntl(0, F_SETFL, flags);
        return(n);
    }
}

void interruptor(int sig) {
    done = sig;
    return;
}

void unset_canon_mode(struct termios* stored_settings) {    //Disable canonical mode and input visibility
    struct termios new_settings;
    tcgetattr(0, stored_settings);
    new_settings = *stored_settings;

    new_settings.c_lflag &= ~(ICANON | ECHO);

    tcsetattr(0, TCSANOW, &new_settings);
    return;
}

void restore_mode(struct termios* stored_settings) {    //Return canonical mode and input visibility
    tcsetattr(0, TCSANOW, stored_settings);
    return;
}

int main(int argc, char** argv) {
    int x,y;
    int rows, columns;
    int tempColor = 0;
    int bgColor = 40;
    struct termios st_sets;
    struct termios* stored_settings = &st_sets;

    rows = con::romax();
    columns = con::comax();
    x = 1; y = columns;

    std::cout << con::ED << con::CUP(1,1);
    signal(SIGINT, interruptor);

    unset_canon_mode(stored_settings);

    while (done < 1) {
        for ( ; x <= rows; x++) {
            std::cout << con::CUP(x, y) << con::SGR(bgColor) << " ";
        }
        x = 1;
        if (--y == 0) {
            y = columns;
            tempColor = (tempColor + 1) % 8;
            bgColor = 40 + tempColor;
        }
        if (con::kbin() > 0) {
            break;
        }
    }

    std::cout << con::CUP(1, 1) << con::SGR(0) << con::ED;

    restore_mode(stored_settings);
    return(0);
}