#include <u.h>
#include <libc.h>
#include <draw.h>
#include "abuf.h"

double *samples;
int n, max, frame;

enum {
	Fps = 25,
	Srate = 48000,
};

void
eresized(int new)
{
	if(new && getwindow(display, Refnone) < 0)
		sysfatal("can't reattach to window");
	
	frame = Srate / Fps;
	max = Dx(screen->r);
	n = 0;
	samples = realloc(samples, sizeof(*samples * frame));
}

void
drawframe(void)
{
	Point a, b;
	int i, x, y, h;
	
	draw(screen, screen->r, display->white, nil, ZP);
	x = screen->r.min.x;
	y = screen->r.min.y;
	h = Dy(screen->r);
	for(i=0; i<max-1; i++){
		a = Pt(x + i, y + (samples[i] + 1.0) * h / 2);
		b = Pt(x + i + 1, y + (samples[i+1] + 1.0) * h / 2);
		line(screen, a, b, 0, 0, 0, display->black, ZP);
	}
	flushimage(display, 1);
}

Abuf ain, aout;

void
main(int argc, char *argv[])
{
	double s;
	
	if(initdraw(nil, nil, "oscope") < 0)
 		sysfatal("initdraw: %r");
 	
 	eresized(0);
 	
 	ainit(&ain, 0);
	ainit(&aout, 1);

	while(agetd(&ain, &s) == 1){
		if(n >= frame){
			drawframe();
			n = 0;
		}
		if(n < max)
			samples[n] = s;
		n++;
		aputd(&aout, s);
	}

	exits(0);
}