xurses/xurses.c

/*
 * Copyright (c) 2023 : Ognjen 'xolatile' Milan Robovic
 *
 * Xurses is free software! You will redistribute it or modify it under the terms of the GNU General Public License by Free Software Foundation.
 * And when you do redistribute it or modify it, it will use either version 3 of the License, or (at yours truly opinion) any later version.
 * It is distributed in the hope that it will be useful or harmful, it really depends... But no warranty what so ever, seriously. See GNU/GPLv3.
 */

#ifndef XURSES_SOURCE
#define XURSES_SOURCE

#include <xolatile/xurses.h>

#include <termios.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>

#define CURSES_LENGTH ((int) sizeof ("\033[-;3-m-\033[0m") - 1)
#define CURSES_OFFSET ((int) sizeof ("\033[H")             - 1)
#define CURSES_RETURN ((int) sizeof ("\r\n")               - 1)

static int    curses_stop          = SIGNAL_Q;
static int    curses_signal        = SIGNAL_NONE;
static int    curses_screen_width  = 0;
static int    curses_screen_height = 0;
static int    curses_screen_size   = 0;
static char * curses_screen        = NULL;

static char curses_format [CURSES_LENGTH + 1] = "\033[-;3-m-\033[0m";

static void (* curses_action [SIGNAL_COUNT]) (void) = { 0 };

static struct termios curses_old_terminal;
static struct termios curses_new_terminal;

int curses_active = 0;

static void curses_free (void) {
	curses_screen = deallocate (curses_screen);

	terminal_clear ();

	fatal_failure (tcsetattr (STDIN_FILENO, TCSAFLUSH, & curses_old_terminal) == -1, "tcsetattr: Failed to set default terminal attributes.");
}

static void curses_screen_offset (void) {
	string_copy (& curses_screen [0], "\033[H");
	curses_screen_size = CURSES_OFFSET;
}

static char * curses_screen_position (int x, int y) {
	fatal_failure (x <= -1,                   "curses_screen_position: X position is below the lower bound.");
	fatal_failure (y <= -1,                   "curses_screen_position: Y position is below the lower bound.");
	fatal_failure (x >= curses_screen_width,  "curses_screen_position: X position is above the upper bound.");
	fatal_failure (y >= curses_screen_height, "curses_screen_position: Y position is above the upper bound.");

	return (& curses_screen [CURSES_LENGTH * (y * curses_screen_width + x) + y * CURSES_RETURN + CURSES_OFFSET]);
}

static char * curses_format_character (char character, int colour, int effect) {
	log_in (LOG_WARNING, character_is_invisible (character), "curses_format_character: Can not format invisible characters.");
	log_in (LOG_FAILURE, colour >= COLOUR_COUNT,             "curses_format_character: Colour is invalid enumeration value.");
	log_in (LOG_FAILURE, effect >= EFFECT_COUNT,             "curses_format_character: Effect is invalid enumeration value.");

	curses_format [2] = (char) (effect % EFFECT_COUNT) + '0';
	curses_format [5] = (char) (colour % COLOUR_COUNT) + '0';
	curses_format [7] = character;

	log_out ("curses.log");

	return (curses_format);
}

static void curses_idle (void) {
	return;
}

void curses_configure (void) {
	struct winsize screen_dimension;

	char signal = 0;
	char offset = 0;

	atexit (curses_free);

	fatal_failure (ioctl (STDOUT_FILENO, TIOCGWINSZ, & screen_dimension) == -1, "ioctl: Failed to get terminal dimensions.");

	curses_screen_width  = (int) screen_dimension.ws_col;
	curses_screen_height = (int) screen_dimension.ws_row;

	fatal_failure (tcgetattr (STDIN_FILENO, & curses_old_terminal) == -1, "tcgetattr: Failed to get default terminal attributes.");

	curses_new_terminal = curses_old_terminal;

	curses_new_terminal.c_cc [VMIN]  = (unsigned char) 0;
	curses_new_terminal.c_cc [VTIME] = (unsigned char) 1;

	curses_new_terminal.c_iflag &= (unsigned int) ~(BRKINT | ICRNL | INPCK | ISTRIP | IXON);
	curses_new_terminal.c_oflag &= (unsigned int) ~(OPOST);
	curses_new_terminal.c_cflag |= (unsigned int)  (CS8);
	curses_new_terminal.c_lflag &= (unsigned int) ~(ECHO | ICANON | IEXTEN | ISIG);

	fatal_failure (tcsetattr (STDIN_FILENO, TCSAFLUSH, & curses_new_terminal) == -1, "tcsetattr: Failed to set reverse terminal attributes.");

	curses_screen = allocate (CURSES_OFFSET + CURSES_LENGTH * curses_screen_width * curses_screen_height + (curses_screen_height - 1) * CURSES_RETURN + 1);

	for (signal = SIGNAL_NONE; signal != SIGNAL_COUNT; ++signal) {
		curses_unbind ((char) signal);
	}

	terminal_clear ();

	curses_screen_offset ();

	for (offset = 0; offset != curses_screen_height - 1; ++offset) {
		string_copy (& curses_screen [CURSES_LENGTH * curses_screen_width * offset + CURSES_OFFSET], "\r\n");
	}

	curses_active = 1;
}

void curses_synchronize (void) {
	curses_signal = '\0';

	out (curses_screen, CURSES_OFFSET + CURSES_LENGTH * curses_screen_width * curses_screen_height/* + curses_screen_height * CURSES_RETURN*/);

	in (& curses_signal, 1);

	switch (curses_signal) {
		case '0': curses_signal = SIGNAL_0;                break;
		case 'Q': curses_signal = SIGNAL_Q | SIGNAL_SHIFT; break;
		case 'q': curses_signal = SIGNAL_Q;                break;
		default:  curses_signal = SIGNAL_NONE;             break;
	}

	if (curses_signal == curses_stop) {
		curses_active = 0;
		return;
	}

	if ((curses_signal > SIGNAL_ANY) && (curses_signal < SIGNAL_COUNT)) {
		curses_action [curses_signal] ();
	}

	curses_screen_offset ();
}

void curses_render_character (char character, int colour, int effect, int x, int y) {
	string_copy (curses_screen_position (x, y), curses_format_character (character, colour, effect));

	curses_screen_size += CURSES_LENGTH;
}

void curses_render_background (char character, int colour, int effect) {
	int x, y;

	for (y = 0; y != curses_screen_height; ++y) {
		for (x = 0; x != curses_screen_width; ++x) {
			curses_render_character (character, colour, effect, x, y);
		}
	}
}

void curses_bind (int signal, void (* action) (void)) {
	curses_action [signal] = action;
}

void curses_unbind (int signal) {
	curses_action [signal] = curses_idle;
}

void curses_exit (int signal) {
	curses_stop = signal;
}

#endif