/*** Includes ***/
#include <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <termios.h>
#include <unistd.h>

/** defines ***/
#define CTRL_KEY(k) ((k) & 0x1f)


/*** data ***/
struct termios orig_termios;

/*** terminal ***/
void die(const char *s){
    perror(s);
    exit(1);
}

void disableRawMode() {
    if(tcsetattr(STDIN_FILENO, TCSAFLUSH, &orig_termios) == -1){
        die("tcsetattr");
    }
}

void enableRawMode() {
    if(tcgetattr(STDIN_FILENO, &orig_termios) == -1) die("tcgetattr");

    atexit(disableRawMode);

    struct termios raw = orig_termios;
    raw.c_iflag &= ~(BRKINT | ICRNL | INPCK | ISTRIP | IXON);
    raw.c_oflag &= ~(OPOST);
    raw.c_cflag |= (CS8);
    raw.c_lflag &= ~(ECHO | ICANON | IEXTEN | ISIG);
    raw.c_cc[VMIN] = 0;
    raw.c_cc[VTIME] = 1;
    if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw) == -1) die("tcsetattr");
}

char editorReadKey() {
    int nread;
    char c;
    while ((nread = read(STDIN_FILENO, &c, 1)) != 1){
        if (nread == -1 && errno != EAGAIN) die("read");
    }
    return c;
}

/*** output ***/
void editorRefreshScreen() {
    write(STDOUT_FILENO, "\x1b[2J", 4); // Clear Screen
    write(STDOUT_FILENO, "\x1b[H",3); // Cursor Position home
}


/*** input ***/
void editorProcessKeypress() {
    char c = editorReadKey();
    switch (c) {
        case CTRL_KEY('q'):
            exit(0);
            break;
    }
}

/*** init ***/
int main() {
    enableRawMode();

    while(1) {
        editorRefreshScreen();
        editorProcessKeypress();
    }
    return 0;
}