/* Draw a character that you can move around on the screen
** Type a lowercase 'q' to exit */

#include <stdlib.h>	/* for exit() */
#include <stdio.h>	/* for printf() */
#include <curses.h>	/* for ncurses */
#include <unistd.h>	/* for usleep() */
#include <signal.h>	/* for handling SIGTERM */

/* Function prototypes */
static void finish(int sig);
static void nextFrame(void);
static void drawFrame(void);

int main(void)
{
	int run=1;	/* Boolean on/off flag, default on */
	int c=0;	/* Character for input. Curses uses ints for chars */
	int xpos=40, ypos=11;	/* X and Y positions of the actor */

	signal(SIGINT, finish);	/* run finish() on sig INT */
	initscr();	/* ncurses won't do anything without this */
	nonl();		/* Allows detection of return key; Not needed here */
	noecho();	/* Don't print what you type back onto the screen */
	keypad(stdscr,TRUE);	/* Allow input from arrow keys */


	drawFrame();		/* Run my drawFrame function */
	mvaddch(ypos,xpos,'O');	/* Draw the actor on the screen */
		
		/* Note that curses uses (Y,X) rather than (X,Y) */

	while(run){
		c=getch();	/* Input a character. Curses uses ints */
		mvaddch(ypos,xpos,' '); /* Blank out the actor's position */

		if(c=='q') run=0; /* Quit on 'q' as input */
		else /* Redraw the actor on other input */
		if(c== (KEY_DOWN) || c=='j')
			  mvaddch(++ypos,xpos,'O');
		else
		if(c==(KEY_RIGHT) || c=='l')
			  mvaddch(ypos,++xpos,'O');
		else
		if(c==(KEY_LEFT) || c=='h')
			  mvaddch(ypos,--xpos,'O');
		else
		if(c==(KEY_UP) || c=='k')
			  mvaddch(--ypos,xpos,'O');
		else
			  mvaddch(xpos,ypos,'?');

		refresh();	/* Nothing shows up on screen without this */
	}
	finish(0);
	return 0;
}

static void finish(int sig)
{
	endwin();	/* Keeps you from having to reset your terminal */
	exit(0);
}

static void nextFrame(void)
{
	refresh();		/* Draw stuff on the screen */
	usleep(1024*16);	/* Sleep 1/64th of a second */
}

/* Draw an 80x21 char frame */
static void drawFrame(void){
	int i=0, j=0;	/* Loop counters */

	/* Draw the top and left sides of the frame */
	while(j<80){
		mvaddch(0,j++,'#');
		if(!(j%4)) mvaddch(++i,0,'#');
		nextFrame();
	}

	i=j=0;

	/* Draw the right and bottom sides of the frame */
	while(j<80){
		mvaddch(20,++j,'#');
		if(!(j%4)) mvaddch(++i,79,'#');
		nextFrame();
	}
}