#include <u.h>
#include <libc.h>
#include <thread.h>
#include <draw.h>
#include <memdraw.h>
#include <mouse.h>
#include <keyboard.h>
#include "dat.h"
#include "fns.h"

Mousectl *mctl;
ulong kdown;
double Δt;
Image *screenb;
Memimage *fb;
Memimage *pal[NCOLOR];
Sprite bob;

Rune keys[Ke] = {
 [KR↺]	'q',
 [KR↻]	'e',
 [K↑]	Kup,
 [K↓]	Kdown,
 [K←]	Kleft,
 [K→]	Kright
};

Memimage*
eallocmemimage(Rectangle r, ulong chan)
{
	Memimage *i;

	i = allocmemimage(r, chan);
	if(i == nil)
		sysfatal("allocmemimage: %r");
	memfillcolor(i, DTransparent);
	return i;
}

Memimage*
rgb(ulong c)
{
	Memimage *i;

	i = eallocmemimage(Rect(0,0,1,1), screen->chan);
	i->flags |= Frepl;
	i->clipr = Rect(-1e6, -1e6, 1e6, 1e6);
	memfillcolor(i, c);
	return i;
}

Memimage*
loadsprite(char *path)
{
	Memimage *i;
	int fd;

	fd = open(path, OREAD);
	if(fd < 0)
		sysfatal("open: %r");
	i = readmemimage(fd);
	if(i == nil)
		sysfatal("readmemimage: %r");
	close(fd);
	return i;
}

void
initpal(void)
{
	pal[Cmask] = rgb(MASKCOLOR);
	pal[Cbg] = rgb(DWhite);
	pal[Cfg] = rgb(DBlack);
}

void
kbdproc(void*)
{
	Rune r, *a;
	char buf[128], *s;
	int fd, n;

	threadsetname("kbdproc");
	if((fd = open("/dev/kbd", OREAD)) < 0)
		sysfatal("kbdproc: %r");
	memset(buf, 0, sizeof buf);
	for(;;){
		if(buf[0] != 0){
			n = strlen(buf)+1;
			memmove(buf, buf+n, sizeof(buf)-n);
		}
		if(buf[0] == 0){
			if((n = read(fd, buf, sizeof(buf)-1)) <= 0)
				break;
			buf[n-1] = 0;
			buf[n] = 0;
		}
		if(buf[0] == 'c'){
			if(utfrune(buf, Kdel)){
				close(fd);
				threadexitsall(nil);
			}
		}
		if(buf[0] != 'k' && buf[0] != 'K')
			continue;
		s = buf+1;
		kdown = 0;
		while(*s){
			s += chartorune(&r, s);
			for(a = keys; a < keys+Ke; a++)
				if(r == *a){
					kdown |= 1 << a-keys;
					break;
				}
		}
	}
}

enum{ Frameslice = 1000/30 };
void
drawproc(void *arg)
{
	Channel *c;
	vlong t0, t, dt, tt;
	int fps;
 
 	c = arg;
	fps = 0;
	tt = 0;
	t0 = nsec();
 	for(;;){
 		send(c, nil);
		t = nsec();
		dt = t-t0;
		fps++;
		tt += dt;
		if(tt >= 1e9){
			fprint(2, "fps %d\n", fps);
			tt = fps = 0;
		}
		dt /= 1e6;
		if(dt < Frameslice)
 			sleep(Frameslice - dt);
		t0 = t;
	}
}

void
resetfb(void)
{
	freememimage(fb);
	fb = eallocmemimage(Rect(0,0,Dx(screen->r),Dy(screen->r)), screen->chan);
	freeimage(screenb);
	screenb = allocimage(display, Rect(0,0,Dx(screen->r),Dy(screen->r)), screen->chan, 0, DNofill);
}

double
round(double n)
{
	return floor(n + 0.5);
}

Point
rotatept(Point p, double θ, Point c)
{
	Point r;

	p = subpt(p, c);
	r.x = round(p.x*cos(θ) - p.y*sin(θ));
	r.y = round(p.x*sin(θ) + p.y*cos(θ));
	r = addpt(r, c);
	return r;
}

void
toroidwarp(Point *p)
{
	if(p->x < 0)
		p->x += fb->r.max.x;
	if(p->x >= fb->r.max.x)
		p->x -= fb->r.max.x;
	if(p->y < 0)
		p->y += fb->r.max.y;
	if(p->y >= fb->r.max.y)
		p->y -= fb->r.max.y;
}

void
redraw(void)
{
	Rectangle r;
	Point p, dp;

	memimagedraw(fb, fb->r, pal[Cbg], ZP, nil, ZP, SoverD);
	for(r = ZR; r.min.y < bob.spr->r.max.y; r.min.y++){
		r.min.x = 0;
		r.max.y = r.min.y+1;
		for(; r.min.x < bob.spr->r.max.x; r.min.x++){
			r.max.x = r.min.x+1;
			p = rotatept(r.min, bob.roll, divpt(bob.spr->r.max, 2));
			if(memcmp(byteaddr(bob.spr, p), byteaddr(pal[Cmask], ZP), bob.spr->depth/8) != 0){
				dp = addpt(r.min, bob.p);
				toroidwarp(&dp);
				memimagedraw(fb, Rpt(dp,addpt(dp, Pt(1,1))), bob.spr, p, nil, ZP, SoverD);
			}
		}
	}
	for(r = fb->r; r.min.y < fb->r.max.y; r.min.y++){
		r.max.y = r.min.y+1;
		loadimage(screenb, r, byteaddr(fb, r.min), bytesperline(r, fb->depth));
	}
	lockdisplay(display);
	draw(screen, screen->r, screenb, nil, ZP);
	flushimage(display, 1);
	unlockdisplay(display);
}


void
mouse(void)
{
}

void
resize(void)
{
	if(getwindow(display, Refnone) < 0)
		fprint(2, "can't reattach to window\n");
	resetfb();
	redraw();
}

void
usage(void)
{
	fprint(2, "usage: %s\n", argv0);
	exits("usage");
}

void
threadmain(int argc, char *argv[])
{
	vlong t0, t;
	Channel *drawc;

	ARGBEGIN{
	default: usage();
	}ARGEND;
	if(argc)
		usage();
	if(initdraw(nil, nil, nil) < 0)
		sysfatal("initdraw: %r");
	if(memimageinit() < 0)
		sysfatal("memimageinit: %r");
	if((mctl = initmouse(nil, screen)) == nil)
		sysfatal("initmouse: %r");
	resetfb();
	initpal();
	bob.spr = loadsprite("assets/bob.pic");
	bob.p = divpt(fb->r.max, 2);
	drawc = chancreate(1, 0);
	display->locking = 1;
	unlockdisplay(display);
	proccreate(kbdproc, nil, mainstacksize);
	proccreate(drawproc, drawc, mainstacksize);
	t0 = nsec();
	for(;;){
		enum {MOUSE, RESIZE, DRAW};
		Alt a[] = {
			{mctl->c, &mctl->Mouse, CHANRCV},
			{mctl->resizec, nil, CHANRCV},
			{drawc, nil, CHANRCV},
			{nil, nil, CHANEND}
		};
		switch(alt(a)){
		case MOUSE: mouse(); break;
		case RESIZE: resize(); break;
		case DRAW: redraw(); break;
		}
		t = nsec();
		Δt = (t-t0)/1e9;
		t0 = t;
		if(kdown & 1<<K↑)
			bob.p.y--;
		if(kdown & 1<<K↓)
			bob.p.y++;
		if(kdown & 1<<K←)
			bob.p.x--;
		if(kdown & 1<<K→)
			bob.p.x++;
		if(kdown & 1<<KR↺)
			bob.roll += 1*DEG;
		if(kdown & 1<<KR↻)
			bob.roll -= 1*DEG;
		toroidwarp(&bob.p);
	}
}