/* draw a bouncing ball with variable 
 * coloring, optional trace and size
 * 
 * -- andrey
 */

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

int minx, miny, maxx, maxy;	/* window dimensions */
Point p1;					/* center of circle drawn */

void
eresized(int new)
{
	/* called whenever a window is resized -- reset dimensions and
 	  * restart drawing
	  */
	Rectangle r1;

	if(new && getwindow(display, Refnone) < 0)
		fprint(2,"can't reattach to window");
	r1 = screen->r;
	minx = r1.min.x;
	maxx = r1.max.x;
	miny = r1.min.y;
	maxy = r1.max.y;

	/* circle always starts at same point */
	p1.x = r1.min.x + 100;
	p1.y = r1.min.y + 100;

	/* clean up display */
	draw(screen, r1, display->white, nil, ZP);
}

enum { Msize = 100 };

void
main(int argc, char **argv)
{
	Mouse m;
	Image *img, *imgmask;
	/* img -- color used for drawing ball
	  * imgmask -- black ball on white, mask for drawing an inverse ball
	  */

	int slp = 10;	/* interval between drawings */
	int osize, size = 10;

	Point oldp;	/* previous location of circle */
	
	uint upx = 1;	/* flags for movements, should be enum-ed */
	uint upy = 1;
	uint colors = 0; /* do we draw with random colors */
	uint clear = 1;	/* do we clean up after the circle */

	/* menus for mouse clicks in window */
	char *items[] = { "slower", "faster", "exit", nil };
	char *items2[] = { "clear", "colors",  nil };
	char *items3[] = {"bigger", "smaller",  nil };

	/* ordering does not correspond to mouse buttons -- too lazy to fix */
	Menu menu;
	Menu menu2;
	Menu menu3;

	/* setup menus */
	menu.item = items;
	menu.gen = nil;
	menu2.item = items2;
	menu2.gen = nil;
	menu3.item = items3;
	menu3.gen = nil;

	srand(0);

	initdraw(0,0,"whoopty doo");
	eresized(0);
	einit(Emouse);
	
	imgmask = allocimage(display, Rect(-Msize-2, -Msize-2, Msize+2, Msize+2), GREY1, 0, DWhite);

	osize = 0;
	for(;;){
		/* handle mouse clicks if any */
		if(ecanmouse())	{
			m = emouse();
			if(m.buttons & 4) {
				switch(emenuhit(3, &m, &menu)) {
					case 0: 	slp += 10; break;
					case 1: 	if(slp > 0) 
								slp -= 10;
							else 
								slp = 0; 
							break;
					case 2: 	exits("user abort");
					default: 	;
				}
				//eresized(0);
			} else if(m.buttons & 2) {
				switch(emenuhit(2, &m, &menu2)) {
					case 0:	if (clear)
								clear = 0;
							else
								clear = 1;
							break;
					case 1:	if (colors) 
								colors = 0;
							else
								colors = 1;
						
							break;
					default: ;
				}
				//eresized(0);
			} else if(m.buttons & 1) {
				switch(emenuhit(1, &m, &menu3)) {
					case 0:	if((size += 5) > 100)
								size = 100;
							break;
					case 1:	if((size -= 5) < 1)
								size = 0;
							break;
					default: ;
				}
				//eresized(0);
			}
		
		}
		

		if (colors)
			/* use some sort of random coloring.. ugly */
			img = allocimagemix(display,nrand(256)<<24 | nrand(256) << 16 | nrand(256) <<8 | (256 - nrand(256)),nrand(256)<<24 | nrand(256) << 16 | nrand(256) <<8 | (256 - nrand(256)));
		else 
			/* just draw a black circle */
			img = allocimagemix(display, DBlack, DBlack);
		
		/* calculate new position */
		if (upx)
			oldp.x = p1.x++;
		else 
			oldp.x = p1.x--;
		if(upy)
			oldp.y = p1.y++;
		else
			oldp.y = p1.y--;
		
		/* see if we've reached window limits */		
		if (p1.x - size < minx)
			upx = 1; /* start moving upwards */
		else if (p1.x + size > maxx)
			upx = 0;

		if (p1.y - size < miny)
			upy = 1;
		else if (p1.y +size > maxy)
			upy = 0;

		/* clean up previous location */
		if (osize && clear) {
			draw(imgmask, imgmask->r, display->black, nil, ZP);	// transparent
			fillellipse(imgmask, subpt(oldp, p1), osize, osize, display->white, ZP);	// draw opaque old
			fillellipse(imgmask, ZP, size, size, display->black, ZP);	// cover new

			draw(screen, rectaddpt(imgmask->r, p1), display->white, imgmask, imgmask->r.min);
		}

		/* draw */
		fillellipse(screen, p1, size, size, img, ZP);
		flushimage(display, 1);
		osize = size;

		/* deallocate current colour */
		freeimage(img);

		/* slow down the drawing somehow */
		sleep(slp);
	}
}