term.h

// SPDX-License-Identifier: GPL-3.0-only
// Copyright © 2024  Mario D'Andrea https://ormai.dev

// This header and the accompanying term.c provide a subset of the features of
// ncurses. This is accomplished by relying on the POSIX interface for the
// terminal, and on terminal escape sequences.
//
// - This helped me get started: https://github.com/byllgrim/ansicurses
// - Escape codes: https://gist.github.com/fnky/458719343aabd01cfb17a3a4f7296797

#ifndef TERM_H
#define TERM_H

#include <stdbool.h>
#include <sys/ioctl.h>

#define ESC '\033'
#define CSI "\033[" // Control Sequence Introducer

enum color {
  BLACK = 30,
  RED,
  GREEN,
  YELLOW,
  BLUE,
  MAGENTA,
  CYAN,
  WHITE,
  DEFAULT_COLOR = 39,
  BRIGHT_BLACK = 90,
  BRIGHT_RED,
  BRIGHT_GREEN,
  BRIGHT_YELLO,
  BRIGHT_BLUE,
  BRIGHT_MAGENTA,
  BRIGHT_CYAN,
  BRIGHT_WHITE
};

enum arrow_key {
  ARROW_UP = '\033' + '[' + 'A',
  ARROW_DOWN,
  ARROW_RIGHT,
  ARROW_LEFT
};

// Makes changes to the terminal
void term_init(void);

// Restores the terminal behavior and its previous state
void term_finalize(void);

// Terminals treat the arrow keys as escape sequences
// up: ^[[A, down: ^[[B, right: ^[[C, left: ^[[D; where ^[ is ESC.
// This can be seen by launching cat without a file and pressing the arrow keys.
// This function is just a wrapper around getchar that detects the arrow keys.
int getch(void);

// Returns the terminal size in rows and cols inside the struct winsize
struct winsize get_term_size(void);

// Enable/disable non blocking mode for standard input
void nonblocking_input(const bool enabled);

// Sets the foreground color for standard output
void set_color(const enum color color);

// Erase everything on the terminal, like 'clear' in the command line
void erase(void);

// Erase the y-th line in the terminal
void erase_line(const int y);

// Print a formatted string at line y and column x.
// For multi byte characters to work an appropriate locale must be set.
void print(int y, int x, const char *fmt, ...);

#endif // TERM_H