#include "paint.h"

typedef struct Aux {
	int	fd;
	ImgHdr	hdr;
} Aux;

static int
init(Widget *w)
{
	Aux *aux;

	if((aux = malloc(sizeof(Aux))) == nil) {
		fprint(2, "pipette: alloc aux: %r\n");
		return -1;
	}
	((Canvas *)w->aux)->tool.aux = aux;

	if((aux->fd = open("/dev/screen", OREAD)) < 0) {
		fprint(2, "pipette: open /dev/screen: %r\n");
		return -1;
	}

	if(readimghdr(aux->fd, &aux->hdr) < 0) {
		fprint(2, "pipette: read screen header: %r\n");
		close(aux->fd);
		return -1;
	}

	if(aux->hdr.compressed) {
		fprint(2, "pipette: screen image is compressed\n");
		close(aux->fd);
		return -1;
	}

	return 0;
}

static int
mouse(Widget *w, Mousectl *mctl)
{
	Aux *aux;
	int nc;
	vlong o;
	uchar p[4];
	int n;
	ulong c;
	char chanstr[9];
	Brush *brush, old;
	int b0;

	if((mctl->buttons & 7) == 0)
		return 0;

	aux = ((Canvas *)w->aux)->tool.aux;
	nc = chantodepth(aux->hdr.chan) / 8;

	brush = getbrush(mctl->buttons);
	old = *brush;

	b0 = mctl->buttons;
	do {
		o = 5*12 + (mctl->xy.y * Dx(aux->hdr.r) + mctl->xy.x) * nc;
		if((n = pread(aux->fd, p, nc, o)) < nc) {
			if(n >= 0)
				werrstr("short read: %d/%d", n, nc);
			fprint(2, "pipette: read %P: %r\n", mctl->xy);
			goto err;
		}

		switch(aux->hdr.chan) {
		case XRGB32:
			c = p[2]<<24 | p[1]<<16 | p[0]<<8 | 0xFF;
			break;
		default:
			fprint(2, "pipette: unexpected screen chan: %.*s\n",
				sizeof chanstr, chantostr(chanstr, aux->hdr.chan) );
			goto err;
		}

		brush->c = c;
		brushwidget->sync(brushwidget);
		brushwidget->redraw(brushwidget, RDall);
		setcolorpickercolor(colorpickerwidget, c);
		colorpickerwidget->redraw(colorpickerwidget, RDinc);
		readmouse(mctl);
	} while((mctl->buttons & 7) == b0);

	if(mctl->buttons == 0)
		return 0;
	*brush = old;
	brushwidget->sync(brushwidget);
	brushwidget->redraw(brushwidget, RDall);
	while(mctl->buttons)
		readmouse(mctl);
	return 0;

err:
	while(mctl->buttons)
		readmouse(mctl);
	return -1;
}

static void
cleanup(Widget *w)
{
	Aux *aux;

	aux = ((Canvas *)w->aux)->tool.aux;
	close(aux->fd);
	free(((Canvas *)w->aux)->tool.aux);
}

CanvasTool pipette = {
	mouse,
	init,
	cleanup,
};

/*
	image(6)
	/sys/src/cmd/rio/xfid.c:/Qscreen
*/