#define _esep_ind(i)      (i / 8U)
#define _esep_shift(i)    (4U * (i % 8U))
#define _esep_mask(i)     (((1U << 4U) - 1U) << _esep_shift(i))
#define _visited_ind(i)   (i / 8U)
#define _visited_mask(i)  (1U << (i % 8U))

typedef struct {
	cube_fast_t cube;
	uint8_t *visited;
	uint8_t *moves;
	uint8_t nmoves;
	uint8_t depth;
	uint16_t *nclasses;
	uint32_t *cocsepdata;
	uint32_t *buf32;
} dfsarg_gendata_t;

_static_inline int64_t coord_h48(cube_fast_t, uint32_t *, uint8_t);

_static size_t gendata_cocsep(void *);
_static uint32_t gendata_cocsep_dfs( /* TODO: use dfsarg */
    cube_fast_t, uint8_t, uint8_t, uint16_t *, uint32_t *, uint8_t *);

_static size_t gendata_esep(const void *, void *);
_static uint32_t gendata_esep_dfs(dfsarg_gendata_t *);

_static_inline bool get_visited(const uint8_t *, int64_t);
_static_inline void set_visited(uint8_t *, int64_t);
_static_inline uint8_t get_esep_pval(const uint32_t *, int64_t);
_static_inline void set_esep_pval(uint32_t *, int64_t, uint8_t);

/* h is the number of eo bits used */
_static_inline int64_t
coord_h48(cube_fast_t c, uint32_t *cocsepdata, uint8_t h)
{
	cube_fast_t d;
	int64_t cocsep, coclass, esep, eo, esize, ret;
	uint32_t data;
	uint8_t ttrep;

	DBG_ASSERT(h <= 11, -1, "coord_h48: h must be between 0 and 11\n");

	cocsep = coord_fast_cocsep(c);
	data = cocsepdata[cocsep];
	coclass = (data & (0xFFFFU << 16U)) >> 16U;
	ttrep = (data & (0xFFU << 8U)) >> 8U;

	d = transform(c, ttrep); /* TODO: transform only edges */
	esep = coord_fast_esep(d);
	eo = coord_fast_eo(d);

	esize = (_12c4 * _8c4) << h;
	ret = (coclass * esize) + (esep << h) + (eo >> (11-h));

	return ret;
}

/*
Each element of the cocsep table is a uint32_t used as follows:
  - Lowest 8-bit block: pruning value
  - Second-lower 8-bit block: "ttrep" (transformation to representative)
  - Top 16-bit block: symcoord value
After the data as described above, more auxiliary information is appended:
  - A uint32_t representing the number of symmetry classes
  - A uint32_t representing the highest value of the pruning table
  - One uint32_t for each "line" of the pruning table, representing the number
    of positions having that pruning value.
*/
_static size_t
gendata_cocsep(void *buf)
{
	size_t tablesize = _3p7 << 7U;
	size_t visitedsize = (tablesize + 7U) / 8U;
	size_t infosize = 12;

	cube_fast_t solved;
	uint32_t *buf32, *info, cc;
	uint16_t n;
	uint8_t i, j, visited[visitedsize];

	buf32 = (uint32_t *)buf;
	info = buf32 + tablesize;
	memset(buf32, 0xFFU, 4*tablesize);
	memset(info, 0, 4*infosize);

	solved = cubetofast(solvedcube());
	for (i = 0, n = 0, cc = 0; i < 10; i++) {
		memset(visited, 0, visitedsize);
		DBG_LOG("cocsep: generating depth %" PRIu8 "\n", i);
		cc = gendata_cocsep_dfs(solved, 0, i, &n, buf32, visited);
		info[i+2] = cc;
		DBG_LOG("found %" PRIu32 "\n", cc);
	}

	info[0] = (uint32_t)n;
	info[1] = 9U; /* Known max pruning value */
	DBG_ASSERT(n == COCSEP_CLASSES, 0,
	    "cocsep: computed %" PRIu16 " symmetry classes, "
	    "expected %" PRIu16 "\n", n, COCSEP_CLASSES);

	DBG_LOG("cocsep data computed\n");
	DBG_LOG("Symmetry classes: %" PRIu32 "\n", info[0]);
	DBG_LOG("Maximum pruning value: %" PRIu32 "\n", info[1]);
	DBG_LOG("Pruning value distribution:\n");
	for (j = 0; j < 10; j++)
		DBG_LOG("%" PRIu8 ":\t%" PRIu32 "\n", j, info[j+2]);

	return 4*(tablesize + infosize);
}

_static uint32_t
gendata_cocsep_dfs(
	cube_fast_t c,
	uint8_t depth,
	uint8_t maxdepth,
	uint16_t *n,
	uint32_t *buf32,
	uint8_t *visited
)
{
	uint8_t m, t, tinv, olddepth;
	uint32_t cc;
	int64_t i;
	cube_fast_t d;

	i = coord_fast_cocsep(c);
	olddepth = (uint8_t)(buf32[i] & 0xFFU);
	if (olddepth < depth || get_visited(visited, i))
		return 0;
	set_visited(visited, i);

	if (depth == maxdepth) {
		if ((buf32[i] & 0xFFU) != 0xFFU)
			return 0;

		for (t = 0, cc = 0; t < 48; t++) {
			d = transform(c, t);
			i = coord_fast_cocsep(d);
			set_visited(visited, i);
			tinv = inverse_trans(t);
			cc += (buf32[i] & 0xFFU) == 0xFFU;
			buf32[i] = (*n << 16U) | (tinv << 8U) | depth;
		}
		(*n)++;

		return cc;
	}

	for (m = 0, cc = 0; m < 18; m++) {
		d = move(c, m);
		cc += gendata_cocsep_dfs(d, depth+1, maxdepth, n, buf32, visited);
	}

	return cc;
}

/*
TODO description
generating fixed table with h=0, k=4
*/
_static size_t
gendata_esep(const void *cocsepdata, void *buf)
{
	size_t tablesize = (COCSEP_CLASSES * _12c4 * _8c4) / 2U;
	size_t visitedsize = (tablesize * 2U + 7U) / 8U;
	size_t infosize = 25; /* TODO unknown yet */

	uint32_t *buf32, *info, cc;
	uint8_t moves[20];
	dfsarg_gendata_t arg;

	arg.visited = malloc(visitedsize);
	buf32 = (uint32_t *)buf;
	info = buf32 + tablesize;
	memset(buf32, 0xFFU, 4*tablesize);
	memset(info, 0, 4*infosize);

	arg.cube = cubetofast(solvedcube());
	arg.moves = moves;
	arg.nmoves = 0;
	arg.cocsepdata = (uint32_t *)cocsepdata;
	arg.buf32 = buf32;
	/* TODO loop until no more is done, not until 12! (or hardcode limits)*/
	for (arg.depth = 0, cc = 0; arg.depth < 12; arg.depth++) {
		DBG_LOG("esep: generating depth %" PRIu8 "\n", arg.depth);
		memset(arg.visited, 0, visitedsize);
		cc = gendata_esep_dfs(&arg);
		info[arg.depth+1] = cc;
		DBG_LOG("found %" PRIu32 "\n", cc);
	}
	free(arg.visited);

	return cc;
}

_static uint32_t
gendata_esep_dfs(dfsarg_gendata_t *arg)
{
	uint8_t m, t, olddepth;
	uint32_t cc;
	uint64_t i;
	cube_fast_t d;
	dfsarg_gendata_t nextarg;

	if (!allowednextmove(arg->moves, arg->nmoves))
		return 0;

	if (arg->nmoves > 0)
		arg->cube = move(arg->cube, arg->moves[arg->nmoves-1]);

	i = coord_h48(arg->cube, arg->cocsepdata, 0U);
	olddepth = get_esep_pval(arg->buf32, i);

	if (olddepth < arg->nmoves || get_visited(arg->visited, i))
		return 0;
	set_visited(arg->visited, i);

	if (arg->nmoves == arg->depth) {
		if (olddepth != 15U)
			return 0;

		for (t = 0, cc = 0; t < 48; t++) {
			d = transform(arg->cube, t);
			i = coord_h48(d, arg->cocsepdata, 0U);
			set_visited(arg->visited, i);
			cc += get_esep_pval(arg->buf32, i) == 15U;
			set_esep_pval(arg->buf32, i, arg->depth);
		}

		return cc;
	}


	nextarg = *arg;
	nextarg.nmoves = arg->nmoves + 1;
	for (m = 0, cc = 0; m < 18; m++) {
		nextarg.cube = arg->cube;
		nextarg.moves[arg->nmoves] = m;
		cc += gendata_esep_dfs(&nextarg);
	}

	return cc;
}

_static_inline bool get_visited(const uint8_t *a, int64_t i)
{
	return a[_visited_ind(i)] & _visited_mask(i);
}

_static_inline void set_visited(uint8_t *a, int64_t i)
{
	a[_visited_ind(i)] |= _visited_mask(i);
}

_static_inline uint8_t
get_esep_pval(const uint32_t *buf32, int64_t i)
{
	return (buf32[_esep_ind(i)] & _esep_mask(i)) >> _esep_shift(i);
}

_static_inline void
set_esep_pval(uint32_t *buf32, int64_t i, uint8_t val)
{
	buf32[_esep_ind(i)] =
	    (buf32[_esep_ind(i)] & (~_esep_mask(i))) | (val << _esep_shift(i));
}