Template for command line with ncurses in C

example.c

#include <ctype.h>
#include <curses.h>
#include <locale.h>
#include <string.h>
#include <time.h>

#define CTRL(c) ((c) & 0x1f)
#define FPS 30

static int columns = 80;
static int lines = 24;

static char character = 'A';
static char boxsiz = 5;
#define BOXWY ((lines - boxsiz) / 2)
#define BOXWX ((columns - boxsiz) / 2)

char input[512] = {0};
size_t ix = 0;
size_t ilen = 0;

time_t pvtime = 0;

int main (void)
{
	/* SETUP */
	setlocale(LC_ALL, "");
	initscr();
	noecho();
	nonl();
	getmaxyx(stdscr, lines, columns);

	bool boxw_dirty = TRUE;
	WINDOW *boxw = newwin(boxsiz, 2 * boxsiz, BOXWY, BOXWX);

	bool inputw_dirty = TRUE;
	WINDOW *inputw = newwin(1, columns, lines - 1, 0);
	nodelay(inputw, TRUE);
	keypad(inputw, TRUE);

	pvtime = time(NULL);

	while (1) {
		/* DRAW */
		curs_set(FALSE);
		if (boxw_dirty) {
			wbkgdset(boxw, character);
			wclear(boxw);
			wrefresh(boxw);
			boxw_dirty = FALSE;
		}
		if (inputw_dirty) {
			mvwprintw(inputw, 0, 0, ":%s", input);
			wclrtoeol(inputw);
			wrefresh(inputw);
			inputw_dirty = FALSE;
		}
		wmove(inputw, 0, ix + 1);
		curs_set(TRUE);

		/* EVENT */
		bool exec_flag = FALSE;

		int byte;
		while ((byte = wgetch(inputw)) != ERR) {
			if (byte == EOF) {
				break;
			}
			else if (byte == CTRL('m') || byte == '\n') {
				exec_flag = TRUE;
				break;
			}
			else if (byte == 0x7F /* ascii-DEL */) {
				if (ix > 0)
					input[--ix] = 0;
				boxw_dirty = TRUE;
				continue;
			}
			else if (byte == KEY_RESIZE) {
				clear();
				refresh();
				getmaxyx(stdscr, lines, columns);

				mvwin(boxw, BOXWY, BOXWX);
				boxw_dirty = TRUE;

				mvwin(inputw, lines - 1, 0);
				inputw_dirty = TRUE;
				continue;
			}
			else if (!isprint(byte)) {
				continue;
			}
			if (ix >= sizeof(input) - 1) {
				continue;
			}
			input[ix++] = (char)byte & 0xff;
			input[ix] = 0;
			ilen++;
			inputw_dirty = TRUE;
		}

		if (exec_flag) {
			if (!strcmp(input, "q"))
				break;
			if (!strcmp(input, "quit"))
				break;
			ix = ilen = 0;
			input[ix] = 0;
			inputw_dirty = TRUE;
		}

		/* NEXT */
		napms(1000.0 / FPS);

		/* UPDATE */
		time_t t = time(NULL);
		if (t - pvtime >= 1) {
			if (++character > 'Z')
				character = 'A';
			pvtime = t;
			boxw_dirty = TRUE;
		}
	}
	/* CLOSE */
	delwin(boxw);
	delwin(inputw);
	endwin();
	return 0;
}