#include <u.h>
#include <libc.h>
#include <draw.h>
#include <thread.h>
#include <keyboard.h>
#include <mouse.h>

Keyboardctl *kbctl;
Mousectl    *mctl;

enum {
	RIGHT = 0,
	DOWN,
	LEFT,
	UP
};

int grid[4][4];
int *grid1 = &grid[0][0];

int gameover;
Image *bg, *bgover;
int ntiles;
Image **imgs;

void drawwindow(void);

int
nempty(void)
{
	int i, n;
	n = 0;
	for(i = 0; i < 4*4; i++)
		if(grid1[i] == 0)
			n++;
	return n;
}

void
insert(int pos, int val)
{
	int i, n;
	n = 0;
	for(i = 0; i < 4*4; i++)
		if(grid1[i] == 0){
			if(n == pos){
				grid1[i] = val;
				return;
			}
			n++;
		}
}

void
insertrandom(void)
{
	insert(rand() % nempty(),
	       frand() < 0.9 ? 1 : 2);
}

void
buildrow(int *row[4], int n, int dir)
{
	int i;
	int start, add;

	add = start = 0;
	switch(dir){
	case RIGHT:
		add = 1;
		start = n*4;
		break;
	case DOWN:
		add = 4;
		start = n;
		break;
	case LEFT:
		add = -1;
		start = n*4 + 3;
		break;
	case UP:
		add = -4;
		start = 3*4 + n;
	}
	for(i = 0; i < 4; i++)
		row[i] = &grid1[add*i + start];
}

int
merge(int *row[4])
{
	int nrow[4] = { 0 };
	int i, j;
	int moved;

	j = 3;
	for(i = 3; i >= 0; i--){
		if(*row[i] == 0)
			;
		else if(nrow[j] == 0){
			nrow[j] = *row[i];
		}else if(nrow[j] == *row[i]){
			nrow[j--]++;
		}else
			nrow[--j] = *row[i];
	}
	moved = 0;
	for(i = 0; i < 4; i++){
		if(nrow[i] != *row[i])
			moved = 1;
		*row[i] = nrow[i];
	}
	return moved;
}

int
movesleft(void)
{
	int i, j;

	for(i = 0; i < 4; i++)
		for(j = 0; j < 4; j++){
			if(j > 0)
				if(grid[i][j] == grid[i][j-1])
					return 1;
			if(i > 0)
				if(grid[j][i] == grid[j][i-1])
					return 1;
		}
	return 0;	
}

void
move(int dir)
{
	int i;
	int moved;
	int *row[4];

	moved = 0;
	for(i = 0; i < 4; i++){
		buildrow(row, i, dir);
		moved = merge(row) || moved;
	}
	if(moved)
		insertrandom();

	if(nempty() == 0 && !movesleft())
		gameover = 1;

	drawwindow();
}

void
init(void)
{
//	srand(1);
	srand(time(0));
	insertrandom();
	insertrandom();
}

void
drawwindow(void)
{
	int i, j;
	int n;
	Point p;
	char s[11];

	if(gameover)
		draw(screen, screen->r, bgover, nil, ZP);
	else
		draw(screen, screen->r, bg, nil, ZP);
	for(i = 0; i < 4; i++)
		for(j = 0; j < 4; j++){
			n = grid[i][j];
			snprint(s, 11, "%d", (int)pow(2, n));
			if(n >= ntiles)
				n = ntiles-1;
			p = addpt(screen->r.min, Pt(j*100+5, i*100+5));
			draw(screen, rectaddpt(Rect(0, 0, 90, 90), p),
			     imgs[n], nil, ZP);
			if(n != 0)
				string(screen, addpt(p, Pt(20, 20)),
				       n < 3 ? display->black : display->white,
			               ZP, font, s);
		}
	flushimage(display, 1);
}

void
kbthread(void*)
{
	Rune r;

	for(;;){
		r = recvul(kbctl->c);
		switch(r){
		case L'e':
			print("empty: %d\n", nempty());
			break;
		case Kdown:
			if(!gameover)
				move(DOWN);
			break;
		case Kup:
			if(!gameover)
				move(UP);
			break;
		case Kleft:
			if(!gameover)
				move(LEFT);
			break;
		case Kright:
			if(!gameover)
				move(RIGHT);
			break;
		case L'q':
		case Kdel:
			threadexitsall(nil);
		}
	}
}

void
mthread(void*)
{
	Mouse m;
	for(;;){
		recv(mctl->c, &m);
	}
}

void
resthread(void*)
{
	for(;;){
		recvul(mctl->resizec);
		if(getwindow(display, Refnone) < 0)
			sysfatal("resize failed: %r");
		drawwindow();
	}
}

void
resize(int x, int y)
{
	int fd;
	fd = open("/dev/wctl", OWRITE);
	if(fd >= 0){
		fprint(fd, "resize -dx %d -dy %d", x+8, y+8);
		close(fd);
	}
}

void
threadmain(int argc, char *argv[])
{
	int i;
	int cols[] = { 0xcdc0b4ff,
	               0xeee4daff, 0xede0c8ff, 0xf2b179ff, 0xf59563ff,
	               0xf67c5fff, 0xf65e36ff, 0xedcf72ff, 0xedcc61ff,
	               0xedc850ff, 0xedc53fff, 0xedc22eff, 0x3c3a32ff };

//	newwindow(nil);
	resize(4*100, 4*100);
	if(initdraw(nil, nil, "2049") < 0)
		sysfatal("initdraw: %r");
	kbctl = initkeyboard("/dev/cons");
	if(kbctl == nil)
		sysfatal("initkeyboard: %r");
	mctl = initmouse("/dev/mouse", screen);
	if(mctl == nil)
		sysfatal("initmouse: %r");

	threadcreate(kbthread, nil, mainstacksize);
	threadcreate(mthread, nil, mainstacksize);
	threadcreate(resthread, nil, mainstacksize);

	ntiles = sizeof cols / sizeof cols[0];
	imgs = malloc(ntiles * sizeof imgs[0]);
	for(i = 0; i < ntiles; i++)
		imgs[i] = allocimage(display, Rect(0, 0, 1, 1), screen->chan, 1, cols[i]);
	bg = allocimage(display, Rect(0, 0, 1, 1), screen->chan, 1, 0xbbada0ff);
	bgover = allocimage(display, Rect(0, 0, 1, 1), screen->chan, 1, 0xf3e1d0ff);

	init();

	drawwindow();
	while(1)
		yield();
}