#include <u.h>
#include <libc.h>
#include <draw.h>
#include <event.h>

Image *secclr;

Point
circlept(Point c, int r, int degrees)
{
	double rad;
	rad = (double) degrees * PI/180.0;
	c.x += cos(rad)*r;
	c.y -= sin(rad)*r;
	return c;
}

void
pixel(Image *dst, Point p, Image *src, Point sp)
{
	draw(dst,(Rectangle){p, (Point){p.x+1,p.y+1}}, src, nil, sp);
}

void lineb(Image *dst, Point p0, Point p1, Image *src, Point sp) 
{
	int dx = abs(p1.x - p0.x), sx = p0.x < p1.x ? 1 : -1;
	int dy = -abs(p1.y - p0.y), sy = p0.y < p1.y ? 1 : -1;
	int err = dx + dy, e2;
	for(;;){
		pixel(dst, p0, src, sp);
		if(p0.x == p1.x && p0.y == p1.y) break;
		e2 = 2 * err;
		if(e2 >= dy) { err += dy; p0.x += sx; }
		if(e2 <= dx) { err += dx; p0.y += sy; }
	}
}

void
redraw(Image *screen)
{
	static int tm, ntm;
	static Rectangle r;
	static Point c;
	static int rad;
	static Image *im;
	int i;
	int anghr, angmin, angsec, angsecrev;
	static Tm tms;
	static Tm ntms;

	ntm = time(0);
	if(ntm == tm && eqrect(screen->r, r))
		return;

	ntms = *localtime(ntm);
	anghr = 90-(ntms.hour*5 + ntms.min/12)*6;
	angmin = 90-ntms.min*6;
	angsec = 90-ntms.sec*6;
	angsecrev = 270-ntms.sec*6;

	tm = ntm;
	tms = ntms;
	r = screen->r;
	c = divpt(addpt(r.min, r.max), 2);
	rad = Dx(r) < Dy(r) ? Dx(r) : Dy(r);
	rad /= 2;
	rad -= 20;

	draw(screen, screen->r, display->black, nil, ZP);
	for(i=0; i<60; i++){
		lineb(screen, circlept(c, (i+5) % 5 == 0 ? rad*0.85 : rad*0.9, i*(360/60)), circlept(c, rad, i*(360/60)), display->white, ZP);
	}
	
	lineb(screen, c, circlept(c, (rad*3)/4, angmin), display->white, ZP);
	lineb(screen, c, circlept(c, rad/2, anghr), display->white, ZP);
	lineb(screen, c, circlept(c, (rad*4)/5, angsec), secclr, ZP);
	lineb(screen, c, circlept(c, (rad)/5, angsecrev), secclr, ZP);
	fillellipse(screen, c, 2, 2, secclr, ZP);
	flushimage(display, 1);
}

void
eresized(int new)
{
	if(new && getwindow(display, Refnone) < 0)
		fprint(2,"can't reattach to window");
	redraw(screen);
}

void
main(int, char**)
{
	Event e;
	Mouse m;
	Menu menu;
	char *mstr[] = {"exit", 0};
	int key, timer;
	int t;

	if (initdraw(0, 0, "clock") < 0)
		sysfatal("initdraw failed");

	secclr = allocimagemix(display, DRed, DRed);
	redraw(screen);

	einit(Emouse);
	t = 1000;
	timer = etimer(0, t);

	menu.item = mstr;
	menu.lasthit = 0;
	for(;;) {
		key = event(&e);
		if(key == Emouse) {
			m = e.mouse;
			if(m.buttons & 4) {
				if(emenuhit(3, &m, &menu) == 0)
					exits(0);
			}
		} else if(key == timer) {
			redraw(screen);
		}
	}	
}