#include	<stdio.h>
#include	<curses.h>
#include	<signal.h>
#include	<fcntl.h>

/*
 * bounce1d2.c
 *	purpose	animate using curses and alarm
 *	        demonstrate ASYNC io
 *	note	one handler does the animation
 *		one handler processes keyboard input
 *		the main program just pause()es
 *	compile	cc bounce1.c set_ticker.c -lcurses -o bounce1
 */

/*
 * some global vars that main and the handler use
 */

#define	MESSAGE	" hello "

int	row;	/* current row		*/
int	col;	/* current column	*/
int	dir;	/* where we are going	*/

int	done = 0;
int	delay;		/* bigger => slower	*/

int main()
{
	void	on_ticker();	/* handler for timer	*/
	void	on_keypress();	/* handler for keyboard	*/

	initscr();
	crmode();
	noecho();
	clear();

	row   = 10;		/* start here		*/
	col   = 0;
	dir   = 1;
	delay = 200;		/* 200ms = 0.2 seconds  */

	move(row,col);		/* get into position	*/
	addstr( MESSAGE );	/* note spaces		*/
	signal(SIGALRM, on_ticker );
	set_ticker( delay );
	signal(SIGIO, on_keypress);
	if ( fcntl(0, F_SETOWN, getpid()) == -1 ){
		perror("setown"); exit(1);
	}
	if ( fcntl(0, F_SETFL, O_ASYNC) == -1 ){
		perror("setfl"); exit(1);
	}

	while( !done ){
		pause();
	}
	endwin();
	return 0;
}
void on_keypress()
{
	char	x[100];
	int	i,n;
	int	ndelay;		/* new delay		*/
	int	c;		/* user input		*/

	n = read(0, x, 100);
	for(i=0; i<n; i++){
		c = x[i];
		ndelay = 0;
		if ( c == 'Q' ){ done = 1; break; }
		if ( c == ' ' ){ dir = -dir; }
		if ( c == 'f' && delay > 2 ) ndelay = delay/2;
		if ( c == 's' ) ndelay = delay * 2;
		if ( ndelay > 0 ){
			set_ticker( delay = ndelay );
		}
	}
}

void
on_ticker()
{
	signal(SIGALRM, on_ticker);	/* reset, just in case	*/
	col += dir;			/* move to new column	*/
	move( row, col );		/* then set cursor	*/
	addstr( MESSAGE );		/* redo message		*/
	refresh();			/* and show it		*/

	/*
	 * now handle borders
	 */
	if ( dir == -1 && col == 0 )
		dir = 1;
	else if ( dir == 1 && col+strlen(MESSAGE) >= COLS )
		dir = -1;
}