#define _move(M, c) compose(c, _move_cube_ ## M)
#define _premove(M, c) compose(_move_cube_ ## M, c)

_static cube_t solvedcube(void);
_static bool isconsistent(cube_t);
_static bool issolvable(cube_t);
_static bool issolved(cube_t);
_static bool iserror(cube_t);
_static cube_t applymoves(cube_t, const char *);
_static cube_t applytrans(cube_t, const char *);
_static cube_t frommoves(const char *);

_static int permsign(uint8_t *, int);
_static cube_t move(cube_t, uint8_t);
_static cube_t transform_edges(cube_t, uint8_t);
_static cube_t transform_corners(cube_t, uint8_t);
_static cube_t transform(cube_t, uint8_t);

_static cube_t
solvedcube(void)
{
	return solved;
}

_static bool
isconsistent(cube_t cube)
{
	uint8_t i, p, e, piece, corner[8], edge[12];
	bool found[12];

	pieces(&cube, corner, edge);

	for (i = 0; i < 12; i++)
		found[i] = false;
	for (i = 0; i < 12; i++) {
		piece = edge[i];
		p = piece & _pbits;
		e = piece & _eobit;
		if (p >= 12)
			goto inconsistent_ep;
		if (e != 0 && e != _eobit)
			goto inconsistent_eo;
		found[p] = true;
	}
	for (i = 0; i < 12; i++)
		if (!found[i])
			goto inconsistent_ep;

	for (i = 0; i < 8; i++)
		found[i] = false;
	for (i = 0; i < 8; i++) {
		piece = corner[i];
		p = piece & _pbits;
		e = piece & _cobits;
		if (p >= 8)
			goto inconsistent_cp;
		if (e != 0 && e != _ctwist_cw && e != _ctwist_ccw)
			goto inconsistent_co;
		found[p] = true;
	}
	for (i = 0; i < 8; i++)
		if (!found[i])
			goto inconsistent_co;

	return true;

inconsistent_ep:
	DBG_LOG("Inconsistent EP\n");
	return false;
inconsistent_cp:
	DBG_LOG("Inconsistent CP\n");
	return false;
inconsistent_eo:
	DBG_LOG("Inconsistent EO\n");
	return false;
inconsistent_co:
	DBG_LOG("Inconsistent CO\n");
	return false;
}

_static bool
issolvable(cube_t cube)
{
	uint8_t i, eo, co, piece, edge[12], corner[8], ep[12], cp[8];

	DBG_ASSERT(isconsistent(cube), false,
	    "issolvable: cube is inconsistent\n");

	pieces(&cube, corner, edge);
	for (i = 0; i < 12; i++)
		ep[i] = edge[i] & _pbits;
	for (i = 0; i < 8; i++)
		cp[i] = corner[i] & _pbits;

	if (permsign(ep, 12) != permsign(cp, 8))
		goto issolvable_parity;

	eo = 0;
	for (i = 0; i < 12; i++) {
		piece = edge[i];
		eo += (piece & _eobit) >> _eoshift;
	}
	if (eo % 2 != 0)
		goto issolvable_eo;

	co = 0;
	for (i = 0; i < 8; i++) {
		piece = corner[i];
		co += (piece & _cobits) >> _coshift;
	}
	if (co % 3 != 0)
		goto issolvable_co;

	return true;

issolvable_parity:
	DBG_LOG("EP and CP parities are different\n");
	return false;
issolvable_eo:
	DBG_LOG("Odd number of flipped edges\n");
	return false;
issolvable_co:
	DBG_LOG("Sum of corner orientation is not multiple of 3\n");
	return false;
}

bool
issolved(cube_t cube)
{
	return equal(cube, solved);
}

bool
iserror(cube_t cube)
{
	return equal(cube, zero);
}

_static cube_t
applymoves(cube_t cube, const char *buf)
{
	uint8_t r, m;
	const char *b;

	DBG_ASSERT(isconsistent(cube), zero,
	    "move error: inconsistent cube\n");

	for (b = buf; *b != '\0'; b++) {
		while (*b == ' ' || *b == '\t' || *b == '\n')
			b++;
		if (*b == '\0')
			goto applymoves_finish;
		if ((r = readmove(*b)) == _error)
			goto applymoves_error;
		if ((m = readmodifier(*(b+1))) != 0)
			b++;
		cube = move(cube, r + m);
	}

applymoves_finish:
	return cube;

applymoves_error:
	DBG_LOG("applymoves error\n");
	return zero;
}

_static cube_t
frommoves(const char *buf)
{
	return applymoves(solved, buf);
}

_static cube_t
applytrans(cube_t cube, const char *buf)
{
	uint8_t t;

	DBG_ASSERT(isconsistent(cube), zero,
	    "transformation error: inconsistent cube\n");

	t = readtrans(buf);

	return transform(cube, t);
}

_static int
permsign(uint8_t *a, int n)
{
	int i, j;
	uint8_t ret = 0;

	for (i = 0; i < n; i++)
		for (j = i+1; j < n; j++)
			ret += a[i] > a[j] ? 1 : 0;

	return ret % 2;
}

_static cube_t
move(cube_t c, uint8_t m)
{
	switch (m) {
	case _move_U:
		return _move(U, c);
	case _move_U2:
		return _move(U2, c);
	case _move_U3:
		return _move(U3, c);
	case _move_D:
		return _move(D, c);
	case _move_D2:
		return _move(D2, c);
	case _move_D3:
		return _move(D3, c);
	case _move_R:
		return _move(R, c);
	case _move_R2:
		return _move(R2, c);
	case _move_R3:
		return _move(R3, c);
	case _move_L:
		return _move(L, c);
	case _move_L2:
		return _move(L2, c);
	case _move_L3:
		return _move(L3, c);
	case _move_F:
		return _move(F, c);
	case _move_F2:
		return _move(F2, c);
	case _move_F3:
		return _move(F3, c);
	case _move_B:
		return _move(B, c);
	case _move_B2:
		return _move(B2, c);
	case _move_B3:
		return _move(B3, c);
	default:
		DBG_LOG("move error, unknown move\n");
		return zero;
	}
}

/*
TODO transform is now relegated to a separated file because it is too long.
It would be nice to make it shorter without loosing performance.
*/