#include <u.h>
#include <libc.h>
#include <draw.h>
#include <thread.h>
#include <mouse.h>
#include <keyboard.h>
enum{GAP = 12};
typedef struct Card Card;
struct Card{int v; Card *next;}deck[52], *cell[4], *found[4], *tab[8], **from;
void
setfrom(Card **new){
	if(*new == nil)
		return;
	from = new;
	if(cell[0] == nil || cell[1] == nil || cell[2] == nil || cell[3] == nil
	|| tab[0] == nil || tab[1] == nil || tab[2] == nil || tab[3] == nil
	|| tab[4] == nil || tab[5] == nil || tab[6] == nil || tab[7] == nil
	|| (*from)->v % 13 == 0
	|| (*from)->v == found[0]->v + 1
	|| (*from)->v == found[1]->v + 1
	|| (*from)->v == found[2]->v + 1
	|| (*from)->v == found[3]->v + 1)
		return;
	for(new = tab; new <= tab + 7; new++)
		if((*from)->v % 13 + 1 == (*new)->v % 13
		&& (*from)->v >= 13 & (*from)->v < 39 ^ (*new)->v >= 13 & (*new)->v < 39)
			return;
	from = nil;
}
int
move(Card **to){
	Card *tmp;
	if(to >= cell && to <= cell + 3 && *to != nil
	|| to >= found && to <= found + 3 &&
	(*to == nil && (*from)->v % 13
	|| *to != nil && ((*from)->v % 13 == 0 || (*from)->v != (*to)->v + 1))
	|| to >= tab && to <= tab + 7 && *to != nil &&
	((*from)->v % 13 + 1 != (*to)->v % 13
	|| ((*from)->v >= 13 && (*from)->v < 39) == ((*to)->v >= 13 && (*to)->v < 39)))
		return 0;
	tmp = (*from)->next;
	(*from)->next = *to;
	*to = *from;
	*from = tmp;
	from = nil;
	return 1;
}
void
automove(void){
	Card **cp;
	for(cp = found; cp < found + 4; cp++)
		if(cp != from && move(cp))
			return;
	for(cp = tab; cp < tab + 8; cp++)
		if(*cp != nil && cp != from && move(cp))
			return;
	for(cp = tab; cp < tab + 8; cp++)
		if(cp != from && move(cp))
			return;
	for(cp = cell; cp < cell + 4; cp++)
		if(cp != from && move(cp))
			return;
	from = nil;
}
void
threadmain(int, char**){
	Keyboardctl *kbd;
	Mousectl *m;
	Image *bg, *fg, *cards;
	Card **cp, *c;
	Rune k;
	Rectangle r;
	int w, h, i, j, b;
	enum{REDRAW, MOUSE, KEYBOARD};
	Alt a[] = {
		[REDRAW]{nil, nil, CHANRCV},
		[MOUSE]{nil, nil, CHANRCV},
		[KEYBOARD]{nil, &k, CHANRCV},
		{nil, nil, CHANEND}
	};
	if(initdraw(nil, nil, "freecell") < 0)
		sysfatal("initdraw: %r");
	r = Rect(0,0,1,1);
	bg = allocimage(display, r, RGBA32, 1, DDarkgreen);
	fg = allocimage(display, r, RGBA32, 1, DPaleyellow);
	if(bg == nil || fg == nil)
		sysfatal("allocimage: %r");
	if((i = open("/sys/games/lib/cards/default.bit", OREAD)) < 0)
		sysfatal("couldn't find cards: %r");
	if((cards = readimage(display, i, 0)) == nil)
		sysfatal("readimage: /sys/games/lib/cards/default.bit bad format");
	close(i);
	w = Dx(cards->r) / 13;
	h = Dy(cards->r) / 4;
	if((m = initmouse(nil, screen)) == nil)
		sysfatal("initmouse: %r");
	a[REDRAW].c = m->resizec;
	a[MOUSE].c = m->c;
	a[MOUSE].v = &m->Mouse;
	if((kbd = initkeyboard(nil)) == nil)
		sysfatal("initkeyboard: %r");
	a[KEYBOARD].c = kbd->c;
	srand(truerand());
	for(j = 0; j < 52; j++)
		deck[j].v = j;
	while(j > 1){
		i = nrand(j--);
		b = deck[i].v;
		deck[i].v = deck[j].v;
		deck[j].v = b;
	}
	for(i = 0; i < 8; i++)
		tab[i] = deck + i;
	for(; i < 52; i++)
		deck[i - 8].next = deck + i;
	sendul(m->resizec, 1);
	for(;;)
		switch(alt(a)){
		case MOUSE:
			if(!m->buttons)
				break;
			b = m->buttons;
			do readmouse(m); while(m->buttons);
			i = m->xy.x - (screen->r.min.x + screen->r.max.x - 8 * w - 7 * GAP >> 1);
			j = m->xy.y - screen->r.min.y - GAP;
			if(i < 0 || j < 0 || i % (w + GAP) >= w || (i /= w + GAP) >= 8)
				from = nil;
			else{
				if(j < h){
					cp = i < 4 ? cell + i : found + i - 4;
					if(b & 6)
						from = cp;
					if(from == cp)
						automove();
					else if(from == nil)
						setfrom(cp);
					else
						move(cp);
				}
				else if(j < h + GAP)
					from = nil;
				else if(tab[i] == nil){
					if(j < 2 * h + GAP && from != nil)
						move(tab + i);
					from = nil;
				}
				else{
					for(c = tab[i]; c->next != nil; c = c->next)
						j -= h / 4;
					if(j < h + GAP || j >= 2 * h + GAP)
						from = nil;
					else{
						if(b & 6)
							from = tab + i;
						if(tab + i == from)
							automove();
						else if(from == nil)
							setfrom(tab + i);
						else
							move(tab + i);
					}
				}
			}
			if(0)
		case REDRAW:
			if(getwindow(display, Refnone) < 0)
				sysfatal("getwindow: %r");
			draw(screen, screen->r, bg, nil, ZP);
			r.min.x = screen->r.min.x + screen->r.max.x + 8 * w + 9 * GAP >> 1;
			r.min.y = screen->r.min.y + GAP;
			r.max.y = r.min.y + h;
			for(i = 0, cp = found + 3; i < 8; i++){
				r.max.x = r.min.x - GAP;
				r.min.x = r.max.x - w;
				if(*cp == nil)
					border(screen, r, 1, fg, ZP);
				else
					draw(screen, r, cards, nil, Pt((*cp)->v % 13 * w, (*cp)->v / 13 * h));
				if(from == cp)
					border(screen, r, GAP / -2, fg, ZP);
				cp = cp == found ? cell + 3 : cp - 1;
			}
			for(i = 0; i < 8; i++, r.min.x = r.max.x + GAP){
				r.max.x = r.min.x + w;
				r.min.y = screen->r.min.y + h + 2 * GAP;
				if(tab[i] == nil){
					r.max.y = r.min.y + h;
					border(screen, r, 1, fg, ZP);
					continue;
				}
				for(c = tab[i]; c->next != nil; c = c->next)
					r.min.y += h / 4;
				r.max.y = r.min.y + h;
				if(from == tab + i)
					border(screen, r, GAP / -2, fg, ZP);
				for(c = tab[i]; c != nil; c = c->next){
					draw(screen, r, cards, nil, Pt(c->v % 13 * w, c->v / 13 * h));
					r.max.y = r.min.y;
					r.min.y = r.max.y - h / 4;
				}
			}
			flushimage(display, 1);
			break;
		case KEYBOARD:
			switch(k){
			case Kdel: case 'q':
				threadexitsall(nil);
			case Kesc:
				if((i = open("/dev/wctl", OWRITE)) >= 0){
					write(i, "hide", 4);
					close(i);
				}
				break;
			}
			break;
		default:
			sysfatal("evpla laxa landicosa");
		}
}