/*-
 * Copyright 2016 Vsevolod Stakhov
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#include "config.h"
#include "util.h"
#include "rspamd.h"
#include "message.h"
#include "symbols_cache.h"
#include "cfg_file.h"
#include "lua/lua_common.h"
#include "unix-std.h"
#include <math.h>

#define msg_err_cache(...) rspamd_default_log_function (G_LOG_LEVEL_CRITICAL, \
        cache->static_pool->tag.tagname, cache->cfg->checksum, \
        G_STRFUNC, \
        __VA_ARGS__)
#define msg_warn_cache(...)   rspamd_default_log_function (G_LOG_LEVEL_WARNING, \
        cache->static_pool->tag.tagname, cache->cfg->checksum, \
        G_STRFUNC, \
        __VA_ARGS__)
#define msg_info_cache(...)   rspamd_default_log_function (G_LOG_LEVEL_INFO, \
        cache->static_pool->tag.tagname, cache->cfg->checksum, \
        G_STRFUNC, \
        __VA_ARGS__)
#define msg_debug_cache(...)  rspamd_default_log_function (G_LOG_LEVEL_DEBUG, \
        cache->static_pool->tag.tagname, cache->cfg->checksum, \
        G_STRFUNC, \
        __VA_ARGS__)

static const guchar rspamd_symbols_cache_magic[8] = {'r', 's', 'c', 1, 0, 0, 0, 0 };

static gint rspamd_symbols_cache_find_symbol_parent (struct symbols_cache *cache,
		const gchar *name);

struct rspamd_symbols_cache_header {
	guchar magic[8];
	guint nitems;
	guchar checksum[64];
	guchar unused[128];
};

struct symbols_cache_order {
	GPtrArray *d;
	ref_entry_t ref;
};

struct symbols_cache {
	/* Hash table for fast access */
	GHashTable *items_by_symbol;
	struct symbols_cache_order *items_by_order;
	GPtrArray *items_by_id;
	GList *delayed_deps;
	GList *delayed_conditions;
	rspamd_mempool_t *static_pool;
	gdouble total_weight;
	guint used_items;
	gdouble total_freq;
	struct rspamd_config *cfg;
	rspamd_mempool_mutex_t *mtx;
	gdouble reload_time;
	struct event resort_ev;
};

struct counter_data {
	gdouble value;
	gint number;
};

struct cache_item {
	/* This block is likely shared */
	gdouble avg_time;
	gdouble weight;
	guint32 frequency;
	guint32 avg_counter;

	/* Per process counter */
	struct counter_data *cd;
	gchar *symbol;
	enum rspamd_symbol_type type;

	/* Callback data */
	symbol_func_t func;
	gpointer user_data;

	/* Condition of execution */
	gint condition_cb;

	/* Parent symbol id for virtual symbols */
	gint parent;
	/* Priority */
	gint priority;
	gint id;

	/* Dependencies */
	GPtrArray *deps;
	GPtrArray *rdeps;
};

struct cache_dependency {
	struct cache_item *item;
	gchar *sym;
	gint id;
};

struct delayed_cache_dependency {
	gchar *from;
	gchar *to;
};

struct delayed_cache_condition {
	gchar *sym;
	gint cbref;
	lua_State *L;
};

struct cache_savepoint {
	guchar *processed_bits;
	guint pass;
	guint version;
	struct metric_result *rs;
	gdouble lim;
	GPtrArray *waitq;
	struct symbols_cache_order *order;
};

/* XXX: Maybe make it configurable */
#define CACHE_RELOAD_TIME 60.0
/* weight, frequency, time */
#define TIME_ALPHA (1.0)
#define WEIGHT_ALPHA (0.1)
#define FREQ_ALPHA (0.01)
#define SCORE_FUN(w, f, t) (((w) > 0 ? (w) : WEIGHT_ALPHA) \
		* ((f) > 0 ? (f) : FREQ_ALPHA) \
		/ (t > TIME_ALPHA ? t : TIME_ALPHA))

static gboolean rspamd_symbols_cache_check_symbol (struct rspamd_task *task,
		struct symbols_cache *cache,
		struct cache_item *item,
		struct cache_savepoint *checkpoint,
		gdouble *total_diff);
static gboolean rspamd_symbols_cache_check_deps (struct rspamd_task *task,
		struct symbols_cache *cache,
		struct cache_item *item,
		struct cache_savepoint *checkpoint);
static void rspamd_symbols_cache_enable_symbol (struct rspamd_task *task,
		struct symbols_cache *cache, const gchar *symbol);
static void rspamd_symbols_cache_disable_all_symbols (struct rspamd_task *task,
		struct symbols_cache *cache);

static GQuark
rspamd_symbols_cache_quark (void)
{
	return g_quark_from_static_string ("symbols-cache");
}

static void
rspamd_symbols_cache_order_dtor (gpointer p)
{
	struct symbols_cache_order *ord = p;

	g_ptr_array_free (ord->d, TRUE);
	g_slice_free1 (sizeof (*ord), ord);
}

static void
rspamd_symbols_cache_order_unref (gpointer p)
{
	struct symbols_cache_order *ord = p;

	REF_RELEASE (ord);
}

static struct symbols_cache_order *
rspamd_symbols_cache_order_new (gsize nelts)
{
	struct symbols_cache_order *ord;

	ord = g_slice_alloc (sizeof (*ord));
	ord->d = g_ptr_array_sized_new (nelts);
	REF_INIT_RETAIN (ord, rspamd_symbols_cache_order_dtor);

	return ord;
}

static gint
cache_logic_cmp (const void *p1, const void *p2, gpointer ud)
{
	const struct cache_item *i1 = *(struct cache_item **)p1,
			*i2 = *(struct cache_item **)p2;
	struct symbols_cache *cache = ud;
	double w1, w2;
	double weight1, weight2;
	double f1 = 0, f2 = 0, t1, t2, avg_freq, avg_weight;

	if (i1->deps->len != 0 || i2->deps->len != 0) {
		/* TODO: handle complex dependencies */
		w1 = 1.0;
		w2 = 1.0;

		if (i1->deps->len != 0) {
			w1 = 1.0 / (i1->deps->len);
		}
		if (i2->deps->len != 0) {
			w2 = 1.0 / (i2->deps->len);
		}
		msg_debug_cache ("deps length: %s -> %.2f, %s -> %.2f",
				i1->symbol, w1 * 1000.0,
				i2->symbol, w2 * 1000.0);
	}
	else if (i1->priority == i2->priority) {
		avg_freq = (cache->total_freq / cache->used_items);
		avg_weight = (cache->total_weight / cache->used_items);
		f1 = (double)i1->frequency / avg_freq;
		f2 = (double)i2->frequency / avg_freq;
		weight1 = fabs (i1->weight) / avg_weight;
		weight2 = fabs (i2->weight) / avg_weight;
		t1 = i1->avg_time;
		t2 = i2->avg_time;
		w1 = SCORE_FUN (weight1, f1, t1);
		w2 = SCORE_FUN (weight2, f2, t2);
		msg_debug_cache ("%s -> %.2f, %s -> %.2f",
				i1->symbol, w1 * 1000.0,
				i2->symbol, w2 * 1000.0);
	}
	else {
		/* Strict sorting */
		w1 = abs (i1->priority);
		w2 = abs (i2->priority);
		msg_debug_cache ("priority: %s -> %.2f, %s -> %.2f",
				i1->symbol, w1 * 1000.0,
				i2->symbol, w2 * 1000.0);
	}

	if (w2 > w1) {
		return 1;
	}
	else if (w2 < w1) {
		return -1;
	}

	return 0;
}

/**
 * Set counter for a symbol
 */
static double
rspamd_set_counter (struct cache_item *item, gdouble value)
{
	struct counter_data *cd;
	cd = item->cd;

	/* Cumulative moving average using per-process counter data */
	if (cd->number == 0) {
		cd->value = 0;
	}

	cd->value = cd->value + (value - cd->value) / (gdouble)(++cd->number);

	return cd->value;
}

static void
rspamd_symbols_cache_resort (struct symbols_cache *cache)
{
	struct symbols_cache_order *ord;
	guint i;
	gpointer p;

	ord = rspamd_symbols_cache_order_new (cache->used_items);

	for (i = 0; i < cache->used_items; i ++) {
		p = g_ptr_array_index (cache->items_by_id, i);
		g_ptr_array_add (ord->d, p);
	}

	g_ptr_array_sort_with_data (ord->d, cache_logic_cmp, cache);

	if (cache->items_by_order) {
		REF_RELEASE (cache->items_by_order);
	}

	cache->items_by_order = ord;
}

/* Sort items in logical order */
static void
rspamd_symbols_cache_post_init (struct symbols_cache *cache)
{
	struct cache_item *it, *dit;
	struct cache_dependency *dep, *rdep;
	struct delayed_cache_dependency *ddep;
	struct delayed_cache_condition *dcond;
	GList *cur;
	guint i, j;
	gint id;

	rspamd_symbols_cache_resort (cache);

	cur = cache->delayed_deps;
	while (cur) {
		ddep = cur->data;

		id = rspamd_symbols_cache_find_symbol_parent (cache, ddep->from);
		if (id != -1) {
			it = g_ptr_array_index (cache->items_by_id, id);
		}
		else {
			it = NULL;
		}

		if (it == NULL) {
			msg_err_cache ("cannot register delayed dependency between %s and %s, "
					"%s is missing", ddep->from, ddep->to, ddep->from);
		}
		else {
			rspamd_symbols_cache_add_dependency (cache, it->id, ddep->to);
		}

		cur = g_list_next (cur);
	}

	cur = cache->delayed_conditions;
	while (cur) {
		dcond = cur->data;

		id = rspamd_symbols_cache_find_symbol_parent (cache, dcond->sym);
		if (id != -1) {
			it = g_ptr_array_index (cache->items_by_id, id);
		}
		else {
			it = NULL;
		}

		if (it == NULL) {
			msg_err_cache (
					"cannot register delayed condition for %s",
					dcond->sym);
			luaL_unref (dcond->L, LUA_REGISTRYINDEX, dcond->cbref);
		}
		else {
			rspamd_symbols_cache_add_condition (cache, it->id, dcond->L,
					dcond->cbref);
		}

		cur = g_list_next (cur);
	}

	for (i = 0; i < cache->items_by_id->len; i ++) {
		it = g_ptr_array_index (cache->items_by_id, i);

		for (j = 0; j < it->deps->len; j ++) {
			dep = g_ptr_array_index (it->deps, j);
			dit = g_hash_table_lookup (cache->items_by_symbol, dep->sym);

			if (dit != NULL) {
				if (dit->parent != -1) {
					dit = g_ptr_array_index (cache->items_by_id, dit->parent);
				}

				rdep = rspamd_mempool_alloc (cache->static_pool, sizeof (*rdep));
				rdep->sym = dep->sym;
				rdep->item = it;
				rdep->id = i;
				g_ptr_array_add (dit->rdeps, rdep);
				dep->item = dit;
				dep->id = dit->id;

				msg_debug_cache ("add dependency from %d on %d", it->id, dit->id);
			}
			else {
				msg_err_cache ("cannot find dependency on symbol %s", dep->sym);
			}
		}
	}
}

static gboolean
rspamd_symbols_cache_load_items (struct symbols_cache *cache, const gchar *name)
{
	struct rspamd_symbols_cache_header *hdr;
	struct stat st;
	struct ucl_parser *parser;
	ucl_object_t *top;
	const ucl_object_t *cur, *elt;
	ucl_object_iter_t it;
	struct cache_item *item, *parent;
	const guchar *p;
	gint fd;
	gpointer map;

	fd = open (name, O_RDONLY);

	if (fd == -1) {
		msg_info_cache ("cannot open file %s, error %d, %s", name,
			errno, strerror (errno));
		return FALSE;
	}

	if (fstat (fd, &st) == -1) {
		close (fd);
		msg_info_cache ("cannot stat file %s, error %d, %s", name,
				errno, strerror (errno));
		return FALSE;
	}

	if (st.st_size < (gint)sizeof (*hdr)) {
		close (fd);
		errno = EINVAL;
		msg_info_cache ("cannot use file %s, error %d, %s", name,
				errno, strerror (errno));
		return FALSE;
	}

	map = mmap (NULL, st.st_size, PROT_READ, MAP_SHARED, fd, 0);

	if (map == MAP_FAILED) {
		close (fd);
		msg_info_cache ("cannot mmap file %s, error %d, %s", name,
				errno, strerror (errno));
		return FALSE;
	}

	close (fd);
	hdr = map;

	if (memcmp (hdr->magic, rspamd_symbols_cache_magic,
			sizeof (rspamd_symbols_cache_magic)) != 0) {
		msg_info_cache ("cannot use file %s, bad magic", name);
		munmap (map, st.st_size);
		return FALSE;
	}

	parser = ucl_parser_new (0);
	p = (const guchar *)(hdr + 1);

	if (!ucl_parser_add_chunk (parser, p, st.st_size - sizeof (*hdr))) {
		msg_info_cache ("cannot use file %s, cannot parse: %s", name,
				ucl_parser_get_error (parser));
		munmap (map, st.st_size);
		ucl_parser_free (parser);
		return FALSE;
	}

	top = ucl_parser_get_object (parser);
	munmap (map, st.st_size);
	ucl_parser_free (parser);

	if (top == NULL || ucl_object_type (top) != UCL_OBJECT) {
		msg_info_cache ("cannot use file %s, bad object", name);
		ucl_object_unref (top);
		return FALSE;
	}

	it = ucl_object_iterate_new (top);

	while ((cur = ucl_object_iterate_safe (it, true))) {
		item = g_hash_table_lookup (cache->items_by_symbol, ucl_object_key (cur));

		if (item) {
			/* Copy saved info */
			/*
			 * XXX: don't save or load weight, it should be obtained from the
			 * metric
			 */
#if 0
			elt = ucl_object_lookup (cur, "weight");

			if (elt) {
				w = ucl_object_todouble (elt);
				if (w != 0) {
					item->weight = w;
				}
			}
#endif
			elt = ucl_object_lookup (cur, "time");
			if (elt) {
				item->avg_time = ucl_object_todouble (elt);
			}

			elt = ucl_object_lookup (cur, "count");
			if (elt) {
				item->avg_counter = ucl_object_toint (elt);
			}

			elt = ucl_object_lookup (cur, "frequency");
			if (elt) {
				item->frequency = ucl_object_toint (elt);
			}

			if ((item->type & SYMBOL_TYPE_VIRTUAL) && item->parent != -1) {
				g_assert (item->parent < (gint)cache->items_by_id->len);
				parent = g_ptr_array_index (cache->items_by_id, item->parent);

				if (parent->weight < item->weight) {
					parent->weight = item->weight;
				}

				/*
				 * We maintain avg_time for virtual symbols equal to the
				 * parent item avg_time
				 */
				parent->avg_time = item->avg_time;
				parent->avg_counter = item->avg_counter;
			}

			cache->total_weight += fabs (item->weight);
			cache->total_freq += item->frequency;
		}
	}

	ucl_object_iterate_free (it);
	ucl_object_unref (top);

	return TRUE;
}

static gboolean
rspamd_symbols_cache_save_items (struct symbols_cache *cache, const gchar *name)
{
	struct rspamd_symbols_cache_header hdr;
	ucl_object_t *top, *elt;
	GHashTableIter it;
	struct cache_item *item;
	struct ucl_emitter_functions *efunc;
	gpointer k, v;
	gint fd;
	FILE *f;
	bool ret;

	fd = open (name, O_CREAT | O_TRUNC | O_WRONLY, 00644);

	if (fd == -1) {
		msg_info_cache ("cannot open file %s, error %d, %s", name,
				errno, strerror (errno));
		return FALSE;
	}

	memset (&hdr, 0, sizeof (hdr));
	memcpy (hdr.magic, rspamd_symbols_cache_magic,
			sizeof (rspamd_symbols_cache_magic));

	if (write (fd, &hdr, sizeof (hdr)) == -1) {
		msg_info_cache ("cannot write to file %s, error %d, %s", name,
				errno, strerror (errno));
		close (fd);

		return FALSE;
	}

	top = ucl_object_typed_new (UCL_OBJECT);
	g_hash_table_iter_init (&it, cache->items_by_symbol);

	while (g_hash_table_iter_next (&it, &k, &v)) {
		item = v;
		elt = ucl_object_typed_new (UCL_OBJECT);
		ucl_object_insert_key (elt, ucl_object_fromdouble (item->weight),
				"weight", 0, false);
		ucl_object_insert_key (elt, ucl_object_fromdouble (item->avg_time),
				"time", 0, false);
		ucl_object_insert_key (elt, ucl_object_fromdouble (item->avg_counter),
				"count", 0, false);
		ucl_object_insert_key (elt, ucl_object_fromint (item->frequency),
				"frequency", 0, false);

		ucl_object_insert_key (top, elt, k, 0, false);
	}

	f = fdopen (fd, "a");
	g_assert (f != NULL);

	efunc = ucl_object_emit_file_funcs (f);
	ret = ucl_object_emit_full (top, UCL_EMIT_JSON_COMPACT, efunc, NULL);
	ucl_object_emit_funcs_free (efunc);
	ucl_object_unref (top);
	fclose (f);

	return ret;
}

gint
rspamd_symbols_cache_add_symbol (struct symbols_cache *cache,
	const gchar *name,
	gint priority,
	symbol_func_t func,
	gpointer user_data,
	enum rspamd_symbol_type type,
	gint parent)
{
	struct cache_item *item = NULL;

	g_assert (cache != NULL);

	if (name == NULL && !(type & SYMBOL_TYPE_CALLBACK)) {
		msg_warn_cache ("no name for non-callback symbol!");
	}
	else if ((type & SYMBOL_TYPE_VIRTUAL) && parent == -1) {
		msg_warn_cache ("no parent symbol is associated with virtual symbol %s",
			name);
	}

	if (name != NULL && !(type & SYMBOL_TYPE_CALLBACK)) {
		if (g_hash_table_lookup (cache->items_by_symbol, name) != NULL) {
			msg_err_cache ("skip duplicate symbol registration for %s", name);
			return -1;
		}
	}

	item = rspamd_mempool_alloc0_shared (cache->static_pool,
			sizeof (struct cache_item));
	item->condition_cb = -1;
	/*
	 * We do not share cd to skip locking, instead we'll just calculate it on
	 * save or accumulate
	 */
	item->cd = rspamd_mempool_alloc0 (cache->static_pool,
			sizeof (struct counter_data));

	if (name != NULL) {
		item->symbol = rspamd_mempool_strdup (cache->static_pool, name);
	}

	item->func = func;
	item->user_data = user_data;
	item->priority = priority;
	item->type = type;

	if ((type & SYMBOL_TYPE_FINE) && item->priority == 0) {
		/* Make priority for negative weighted symbols */
		item->priority = 1;
	}

	item->id = cache->used_items;
	item->parent = parent;
	cache->used_items ++;
	msg_debug_cache ("used items: %d, added symbol: %s", cache->used_items, name);
	rspamd_set_counter (item, 0);
	g_ptr_array_add (cache->items_by_id, item);
	item->deps = g_ptr_array_new ();
	item->rdeps = g_ptr_array_new ();
	rspamd_mempool_add_destructor (cache->static_pool,
			rspamd_ptr_array_free_hard, item->deps);
	rspamd_mempool_add_destructor (cache->static_pool,
			rspamd_ptr_array_free_hard, item->rdeps);

	if (name != NULL && type != SYMBOL_TYPE_CALLBACK) {
		g_hash_table_insert (cache->items_by_symbol, item->symbol, item);
	}

	return item->id;
}

gboolean
rspamd_symbols_cache_add_condition (struct symbols_cache *cache, gint id,
		lua_State *L, gint cbref)
{
	struct cache_item *item;

	g_assert (cache != NULL);

	if (id < 0 || id >= (gint)cache->items_by_id->len) {
		return FALSE;
	}

	item = g_ptr_array_index (cache->items_by_id, id);

	if (item->condition_cb != -1) {
		/* We already have a condition, so we need to remove old cbref first */
		msg_warn_cache ("rewriting condition for symbol %s", item->symbol);
		luaL_unref (L, LUA_REGISTRYINDEX, item->condition_cb);
	}

	item->condition_cb = cbref;

	msg_debug_cache ("adding condition at lua ref %d to %s (%d)",
			cbref, item->symbol, item->id);

	return TRUE;
}

gboolean
rspamd_symbols_cache_add_condition_delayed (struct symbols_cache *cache,
		const gchar *sym, lua_State *L, gint cbref)
{
	gint id;
	struct delayed_cache_condition *ncond;

	g_assert (cache != NULL);
	g_assert (sym != NULL);

	id = rspamd_symbols_cache_find_symbol_parent (cache, sym);

	if (id != -1) {
		/* We already know id, so just register a direct condition */
		return rspamd_symbols_cache_add_condition (cache, id, L, cbref);
	}

	ncond = g_slice_alloc (sizeof (*ncond));
	ncond->sym = g_strdup (sym);
	ncond->cbref = cbref;
	ncond->L = L;

	cache->delayed_conditions = g_list_prepend (cache->delayed_conditions, ncond);

	return TRUE;
}


void
rspamd_symbols_cache_destroy (struct symbols_cache *cache)
{
	GList *cur;
	struct delayed_cache_dependency *ddep;
	struct delayed_cache_condition *dcond;

	if (cache != NULL) {

		if (cache->cfg->cache_filename) {
			/* Try to sync values to the disk */
			if (!rspamd_symbols_cache_save_items (cache,
					cache->cfg->cache_filename)) {
				msg_err_cache ("cannot save cache data to %s",
						cache->cfg->cache_filename);
			}
		}

		if (cache->delayed_deps) {
			cur = cache->delayed_deps;

			while (cur) {
				ddep = cur->data;
				g_free (ddep->from);
				g_free (ddep->to);
				g_slice_free1 (sizeof (*ddep), ddep);
				cur = g_list_next (cur);
			}

			g_list_free (cache->delayed_deps);
		}

		if (cache->delayed_conditions) {
			cur = cache->delayed_conditions;

			while (cur) {
				dcond = cur->data;
				g_free (dcond->sym);
				g_slice_free1 (sizeof (*dcond), dcond);
				cur = g_list_next (cur);
			}

			g_list_free (cache->delayed_conditions);
		}

		g_hash_table_destroy (cache->items_by_symbol);
		rspamd_mempool_delete (cache->static_pool);
		g_ptr_array_free (cache->items_by_id, TRUE);
		REF_RELEASE (cache->items_by_order);
		g_slice_free1 (sizeof (*cache), cache);
	}
}

struct symbols_cache*
rspamd_symbols_cache_new (struct rspamd_config *cfg)
{
	struct symbols_cache *cache;

	cache = g_slice_alloc0 (sizeof (struct symbols_cache));
	cache->static_pool =
			rspamd_mempool_new (rspamd_mempool_suggest_size (), "symcache");
	cache->items_by_symbol = g_hash_table_new (rspamd_str_hash,
			rspamd_str_equal);
	cache->items_by_id = g_ptr_array_new ();
	cache->mtx = rspamd_mempool_get_mutex (cache->static_pool);
	cache->reload_time = CACHE_RELOAD_TIME;
	cache->total_freq = 1;
	cache->total_weight = 1.0;
	cache->cfg = cfg;

	return cache;
}

gboolean
rspamd_symbols_cache_init (struct symbols_cache* cache)
{
	gboolean res;

	g_assert (cache != NULL);


	/* Just in-memory cache */
	if (cache->cfg->cache_filename == NULL) {
		rspamd_symbols_cache_post_init (cache);
		return TRUE;
	}

	/* Copy saved cache entries */
	res = rspamd_symbols_cache_load_items (cache, cache->cfg->cache_filename);
	rspamd_symbols_cache_post_init (cache);

	return res;
}


static void
rspamd_symbols_cache_validate_cb (gpointer k, gpointer v, gpointer ud)
{
	struct cache_item *item = v, *parent;
	struct symbols_cache *cache = (struct symbols_cache *)ud;
	GList *cur;
	struct metric *m;
	struct rspamd_symbol_def *s;
	gboolean skipped, ghost;
	gint p1, p2;

	ghost = item->weight == 0 ? TRUE : FALSE;

	/* Check whether this item is skipped */
	skipped = !ghost;
	g_assert (cache->cfg != NULL);

	if ((item->type &
			(SYMBOL_TYPE_NORMAL|SYMBOL_TYPE_VIRTUAL|SYMBOL_TYPE_COMPOSITE|SYMBOL_TYPE_CLASSIFIER))
			&& g_hash_table_lookup (cache->cfg->metrics_symbols, item->symbol) == NULL) {
		cur = g_list_first (cache->cfg->metrics_list);
		while (cur) {
			m = cur->data;

			if (m->accept_unknown_symbols) {
				GList *mlist;

				skipped = FALSE;
				item->weight = m->unknown_weight;
				s = rspamd_mempool_alloc0 (cache->static_pool,
						sizeof (*s));
				s->name = item->symbol;
				s->weight_ptr = &item->weight;
				g_hash_table_insert (m->symbols, item->symbol, s);
				mlist = g_hash_table_lookup (cache->cfg->metrics_symbols,
						item->symbol);
				mlist = g_list_append (mlist, m);
				g_hash_table_insert (cache->cfg->metrics_symbols,
						item->symbol, mlist);

				msg_info_cache ("adding unknown symbol %s to metric %s", item->symbol,
						m->name);
			}

			cur = g_list_next (cur);
		}
	}
	else {
		skipped = FALSE;
	}

	if (skipped) {
		item->type |= SYMBOL_TYPE_SKIPPED;
		msg_warn_cache ("symbol %s is not registered in any metric, so skip its check",
				item->symbol);
	}

	if (ghost) {
		msg_debug_cache ("symbol %s is registered as ghost symbol, it won't be inserted "
				"to any metric", item->symbol);
	}

	if (item->weight < 0 && item->priority == 0) {
		item->priority ++;
	}

	if ((item->type & SYMBOL_TYPE_VIRTUAL) && item->parent != -1) {
		g_assert (item->parent < (gint)cache->items_by_id->len);
		parent = g_ptr_array_index (cache->items_by_id, item->parent);

		if (fabs (parent->weight) < fabs (item->weight)) {
			parent->weight = item->weight;
		}

		p1 = abs (item->priority);
		p2 = abs (parent->priority);

		if (p1 != p2) {
			parent->priority = MAX (p1, p2);
			item->priority = parent->priority;
		}
	}

	cache->total_weight += fabs (item->weight);
}

static void
rspamd_symbols_cache_metric_validate_cb (gpointer k, gpointer v, gpointer ud)
{
	struct symbols_cache *cache = (struct symbols_cache *)ud;
	const gchar *sym = k;
	struct rspamd_symbol_def *s = (struct rspamd_symbol_def *)v;
	gdouble weight;
	struct cache_item *item;

	weight = *s->weight_ptr;
	item = g_hash_table_lookup (cache->items_by_symbol, sym);

	if (item) {
		item->weight = weight;
	}
}

gboolean
rspamd_symbols_cache_validate (struct symbols_cache *cache,
	struct rspamd_config *cfg,
	gboolean strict)
{
	struct cache_item *item;
	GHashTableIter it;
	GList *cur;
	gpointer k, v;
	struct rspamd_symbol_def *sym_def;
	struct metric *metric;
	gboolean ignore_symbol = FALSE, ret = TRUE;

	if (cache == NULL) {
		msg_err ("empty cache is invalid");
		return FALSE;
	}

	/* Now adjust symbol weights according to default metric */
	if (cfg->default_metric != NULL) {
		g_hash_table_foreach (cfg->default_metric->symbols,
			rspamd_symbols_cache_metric_validate_cb,
			cache);
	}

	g_hash_table_foreach (cache->items_by_symbol,
			rspamd_symbols_cache_validate_cb,
			cache);
	/* Now check each metric item and find corresponding symbol in a cache */
	g_hash_table_iter_init (&it, cfg->metrics_symbols);

	while (g_hash_table_iter_next (&it, &k, &v)) {
		ignore_symbol = FALSE;
		cur = v;

		while (cur) {
			metric = cur->data;
			sym_def = g_hash_table_lookup (metric->symbols, k);

			if (sym_def && (sym_def->flags & RSPAMD_SYMBOL_FLAG_IGNORE)) {
				ignore_symbol = TRUE;
				break;
			}

			cur = g_list_next (cur);
		}

		if (!ignore_symbol) {
			item = g_hash_table_lookup (cache->items_by_symbol, k);

			if (item == NULL) {
				msg_warn_cache (
						"symbol '%s' has its score defined but there is no "
								"corresponding rule registered",
						k);
				if (strict) {
					ret = FALSE;
				}
			}
		}
	}

	return ret;
}

/* Return true if metric has score that is more than spam score for it */
static gboolean
rspamd_symbols_cache_metric_limit (struct rspamd_task *task,
		struct cache_savepoint *cp)
{
	struct metric_result *res;
	GList *cur;
	struct metric *metric;
	double ms;

	if (task->flags & RSPAMD_TASK_FLAG_PASS_ALL) {
		return FALSE;
	}

	cur = task->cfg->metrics_list;

	if (cp->lim == 0.0) {
		/*
		 * Look for metric that has the maximum reject score
		 */
		while (cur) {
			metric = cur->data;
			res = g_hash_table_lookup (task->results, metric->name);

			if (res) {

				ms = res->actions_limits[METRIC_ACTION_REJECT];

				if (!isnan (ms) && cp->lim < ms) {
					cp->rs = res;
					cp->lim = ms;
				}
			}

			cur = g_list_next (cur);
		}
	}

	if (cp->rs) {

		if (cp->rs->score > cp->lim) {
			return TRUE;
		}
	}
	else {
		/* No reject score define, always check all rules */
		cp->lim = -1;
	}

	return FALSE;
}

static void
rspamd_symbols_cache_watcher_cb (gpointer sessiond, gpointer ud)
{
	struct rspamd_task *task = sessiond;
	struct cache_item *item = ud, *it;
	struct cache_savepoint *checkpoint;
	struct symbols_cache *cache;
	gint i, remain = 0;

	checkpoint = task->checkpoint;
	cache = task->cfg->cache;

	/* Specify that we are done with this item */
	setbit (checkpoint->processed_bits, item->id * 2 + 1);

	if (checkpoint->pass > 0) {
		for (i = 0; i < (gint)checkpoint->waitq->len; i ++) {
			it = g_ptr_array_index (checkpoint->waitq, i);

			if (!isset (checkpoint->processed_bits, it->id * 2)) {
				if (!rspamd_symbols_cache_check_deps (task, cache, it,
						checkpoint)) {
					remain ++;
					break;
				}

				rspamd_symbols_cache_check_symbol (task, cache, it, checkpoint,
						NULL);
			}
		}
	}

	msg_debug_task ("finished watcher, %ud symbols waiting", remain);
}

static gboolean
rspamd_symbols_cache_check_symbol (struct rspamd_task *task,
		struct symbols_cache *cache,
		struct cache_item *item,
		struct cache_savepoint *checkpoint,
		gdouble *total_diff)
{
	guint pending_before, pending_after;
	double t1, t2;
	gdouble diff;
	struct rspamd_task **ptask;
	lua_State *L;
	gboolean check = TRUE;
	const gdouble slow_diff_limit = 1e5;

	if (item->type & (SYMBOL_TYPE_NORMAL|SYMBOL_TYPE_CALLBACK)) {

		g_assert (item->func != NULL);
		/* Check has been started */
		setbit (checkpoint->processed_bits, item->id * 2);

		if (RSPAMD_TASK_IS_EMPTY (task) && !(item->type & SYMBOL_TYPE_EMPTY)) {
			check = FALSE;
		}
		else if (item->condition_cb != -1) {
			/* We also executes condition callback to check if we need this symbol */
			L = task->cfg->lua_state;
			lua_rawgeti (L, LUA_REGISTRYINDEX, item->condition_cb);
			ptask = lua_newuserdata (L, sizeof (struct rspamd_task *));
			rspamd_lua_setclass (L, "rspamd{task}", -1);
			*ptask = task;

			if (lua_pcall (L, 1, 1, 0) != 0) {
				msg_info_task ("call to condition for %s failed: %s",
						item->symbol, lua_tostring (L, -1));
				lua_pop (L, 1);
			}
			else {
				check = lua_toboolean (L, -1);
				lua_pop (L, 1);
			}
		}

		if (check) {
			t1 = rspamd_get_ticks ();
			pending_before = rspamd_session_events_pending (task->s);
			/* Watch for events appeared */
			rspamd_session_watch_start (task->s, rspamd_symbols_cache_watcher_cb,
					item);

			msg_debug_task ("execute %s, %d", item->symbol, item->id);
			item->func (task, item->user_data);

			t2 = rspamd_get_ticks ();
			diff = (t2 - t1) * 1e6;

			if (total_diff) {
				*total_diff += diff;
			}

			if (diff > slow_diff_limit) {
				msg_info_task ("slow rule: %s: %d ms", item->symbol,
						(gint)(diff / 1000.));
			}

			rspamd_set_counter (item, diff);
			rspamd_session_watch_stop (task->s);
			pending_after = rspamd_session_events_pending (task->s);

			if (pending_before == pending_after) {
				/* No new events registered */
				setbit (checkpoint->processed_bits, item->id * 2 + 1);

				return TRUE;
			}

			return FALSE;
		}
		else {
			msg_debug_task ("skipping check of %s as its condition is false",
					item->symbol);
			setbit (checkpoint->processed_bits, item->id * 2 + 1);

			return TRUE;
		}
	}
	else {
		setbit (checkpoint->processed_bits, item->id * 2);
		setbit (checkpoint->processed_bits, item->id * 2 + 1);

		return TRUE;
	}
}

static gboolean
rspamd_symbols_cache_check_deps (struct rspamd_task *task,
		struct symbols_cache *cache,
		struct cache_item *item,
		struct cache_savepoint *checkpoint)
{
	struct cache_dependency *dep;
	guint i;
	gboolean ret = TRUE;

	if (item->deps != NULL && item->deps->len > 0) {
		for (i = 0; i < item->deps->len; i ++) {
			dep = g_ptr_array_index (item->deps, i);

			if (dep->item == NULL) {
				/* Assume invalid deps as done */
				continue;
			}

			if (dep->id >= (gint)checkpoint->version) {
				/*
				 * This is dependency on some symbol that is currently
				 * not in this checkpoint. So we just pretend that the
				 * corresponding symbold does not exist
				 */
				continue;
			}

			if (!isset (checkpoint->processed_bits, dep->id * 2 + 1)) {
				if (!isset (checkpoint->processed_bits, dep->id * 2)) {
					/* Not started */
					if (!rspamd_symbols_cache_check_deps (task, cache,
							dep->item,
							checkpoint)) {
						g_ptr_array_add (checkpoint->waitq, item);
						ret = FALSE;
						msg_debug_task ("delayed dependency %d for symbol %d",
								dep->id, item->id);
					}
					else if (!rspamd_symbols_cache_check_symbol (task, cache,
							dep->item,
							checkpoint,
							NULL)) {
						/* Now started, but has events pending */
						ret = FALSE;
						msg_debug_task ("started check of %d symbol as dep for "
										"%d",
								dep->id, item->id);
					}
					else {
						msg_debug_task ("dependency %d for symbol %d is "
								"already processed",
								dep->id, item->id);
					}
				}
				else {
					/* Started but not finished */
					ret = FALSE;
				}
			}
			else {
				msg_debug_task ("dependency %d for symbol %d is already "
						"checked",
						dep->id, item->id);
			}
		}
	}

	return ret;
}

static void
rspamd_symbols_cache_continuation (void *data)
{
	struct rspamd_task *task = data;

	rspamd_task_process (task, RSPAMD_TASK_PROCESS_ALL);
}

static void
rspamd_symbols_cache_tm (gint fd, short what, void *data)
{
	struct rspamd_task *task = data;

	rspamd_session_remove_event (task->s, rspamd_symbols_cache_continuation,
			data);
}

static struct cache_savepoint *
rspamd_symbols_cache_make_checkpoint (struct rspamd_task *task,
		struct symbols_cache *cache)
{
	struct cache_savepoint *checkpoint;

	if (cache->items_by_id->len != cache->items_by_order->d->len) {
		/*
		 * Cache has been modified, need to resort it
		 */
		msg_info_cache ("symbols cache has been modified since last check:"
				" old items: %ud, new items: %ud",
				cache->items_by_order->d->len, cache->items_by_id->len);
		rspamd_symbols_cache_resort (cache);
	}

	checkpoint = rspamd_mempool_alloc0 (task->task_pool, sizeof (*checkpoint));
	/* Bit 0: check started, Bit 1: check finished */
	checkpoint->processed_bits = rspamd_mempool_alloc0 (task->task_pool,
			NBYTES (cache->used_items) * 2);
	checkpoint->waitq = g_ptr_array_new ();
	g_assert (cache->items_by_order != NULL);
	checkpoint->version = cache->items_by_order->d->len;
	checkpoint->order = cache->items_by_order;
	REF_RETAIN (checkpoint->order);
	rspamd_mempool_add_destructor (task->task_pool,
			rspamd_symbols_cache_order_unref, checkpoint->order);
	rspamd_mempool_add_destructor (task->task_pool,
			rspamd_ptr_array_free_hard, checkpoint->waitq);
	task->checkpoint = checkpoint;

	rspamd_create_metric_result (task, DEFAULT_METRIC);

	return checkpoint;
}

static gboolean
rspamd_symbols_cache_process_settings (struct rspamd_task *task,
		struct symbols_cache *cache)
{
	const ucl_object_t *wl, *cur, *disabled, *enabled;
	struct metric *def;
	struct rspamd_symbols_group *gr;
	GHashTableIter gr_it;
	ucl_object_iter_t it = NULL;
	gpointer k, v;

	wl = ucl_object_lookup (task->settings, "whitelist");

	if (wl != NULL) {
		msg_info_task ("<%s> is whitelisted", task->message_id);
		task->flags |= RSPAMD_TASK_FLAG_SKIP;
		return TRUE;
	}

	enabled = ucl_object_lookup (task->settings, "symbols_enabled");

	if (enabled) {
		/* Disable all symbols but selected */
		rspamd_symbols_cache_disable_all_symbols (task, cache);
		it = NULL;

		while ((cur = ucl_iterate_object (enabled, &it, true)) != NULL) {
			rspamd_symbols_cache_enable_symbol (task, cache,
					ucl_object_tostring (cur));
		}
	}

	/* Enable groups of symbols */
	enabled = ucl_object_lookup (task->settings, "groups_enabled");
	def = g_hash_table_lookup (task->cfg->metrics, DEFAULT_METRIC);

	if (def && enabled) {
		it = NULL;
		rspamd_symbols_cache_disable_all_symbols (task, cache);

		while ((cur = ucl_iterate_object (enabled, &it, true)) != NULL) {
			if (ucl_object_type (cur) == UCL_STRING) {
				gr = g_hash_table_lookup (def->groups,
						ucl_object_tostring (cur));

				if (gr) {
					g_hash_table_iter_init (&gr_it, gr->symbols);

					while (g_hash_table_iter_next (&gr_it, &k, &v)) {
						rspamd_symbols_cache_enable_symbol (task, cache, k);
					}
				}
			}
		}
	}

	disabled = ucl_object_lookup (task->settings, "symbols_disabled");

	if (disabled) {
		it = NULL;

		while ((cur = ucl_iterate_object (disabled, &it, true)) != NULL) {
			rspamd_symbols_cache_disable_symbol (task, cache,
					ucl_object_tostring (cur));
		}
	}

	/* Disable groups of symbols */
	disabled = ucl_object_lookup (task->settings, "groups_disabled");
	def = g_hash_table_lookup (task->cfg->metrics, DEFAULT_METRIC);

	if (def && disabled) {
		it = NULL;

		while ((cur = ucl_iterate_object (disabled, &it, true)) != NULL) {
			if (ucl_object_type (cur) == UCL_STRING) {
				gr = g_hash_table_lookup (def->groups,
						ucl_object_tostring (cur));

				if (gr) {
					g_hash_table_iter_init (&gr_it, gr->symbols);

					while (g_hash_table_iter_next (&gr_it, &k, &v)) {
						rspamd_symbols_cache_disable_symbol (task, cache, k);
					}
				}
			}
		}
	}

	return FALSE;
}

gboolean
rspamd_symbols_cache_process_symbols (struct rspamd_task * task,
	struct symbols_cache *cache)
{
	struct cache_item *item = NULL;
	struct cache_savepoint *checkpoint;
	gint i;
	gdouble total_microseconds = 0;
	const gdouble max_microseconds = 3e5;
	guint start_events_pending;

	g_assert (cache != NULL);

	if (task->checkpoint == NULL) {
		checkpoint = rspamd_symbols_cache_make_checkpoint (task, cache);
		task->checkpoint = checkpoint;
	}
	else {
		checkpoint = task->checkpoint;
	}

	if (task->settings) {
		if (rspamd_symbols_cache_process_settings (task, cache)) {
			return TRUE;
		}
	}

	msg_debug_task ("symbols processing stage at pass: %d", checkpoint->pass);
	start_events_pending = rspamd_session_events_pending (task->s);

	if (checkpoint->pass == 0) {

		/*
		 * On the first pass we check symbols that do not have dependencies
		 * If we figure out symbol that has no dependencies satisfied, then
		 * we just save it for another pass
		 */
		for (i = 0; i < (gint)checkpoint->version; i ++) {
			if (rspamd_symbols_cache_metric_limit (task, checkpoint)) {
				msg_info_task ("<%s> has already scored more than %.2f, so do "
								"not "
						"plan any more checks", task->message_id,
						checkpoint->rs->score);
				return TRUE;
			}

			item = g_ptr_array_index (checkpoint->order->d, i);

			if (!isset (checkpoint->processed_bits, item->id * 2)) {
				if (!rspamd_symbols_cache_check_deps (task, cache, item,
						checkpoint)) {
					msg_debug_task ("blocked execution of %d unless deps are "
									"resolved",
							item->id);
					g_ptr_array_add (checkpoint->waitq, item);
					continue;
				}

				rspamd_symbols_cache_check_symbol (task, cache, item,
						checkpoint, &total_microseconds);
			}

			if (total_microseconds > max_microseconds) {
				/* Maybe we should stop and check pending events? */
				if (rspamd_session_events_pending (task->s) > start_events_pending) {
					/* Add some timeout event to avoid too long waiting */
#if 0
					struct event *ev;
					struct timeval tv;

					rspamd_session_add_event (task->s,
							rspamd_symbols_cache_continuation, task,
							rspamd_symbols_cache_quark ());
					ev = rspamd_mempool_alloc (task->task_pool, sizeof (*ev));
					event_set (ev, -1, EV_TIMEOUT, rspamd_symbols_cache_tm, task);
					event_base_set (task->ev_base, ev);
					msec_to_tv (50, &tv);
					event_add (ev, &tv);
					rspamd_mempool_add_destructor (task->task_pool,
							(rspamd_mempool_destruct_t)event_del, ev);
#endif
					msg_info_task ("trying to check async events after spending "
							"%d microseconds processing symbols",
							(gint)total_microseconds);

					return TRUE;
				}
			}
		}

		checkpoint->pass ++;
	}
	else {
		/* We just go through the blocked symbols and check if they are ready */
		for (i = 0; i < (gint)checkpoint->waitq->len; i ++) {
			item = g_ptr_array_index (checkpoint->waitq, i);

			if (item->id >= (gint)checkpoint->version) {
				continue;
			}

			if (!isset (checkpoint->processed_bits, item->id * 2)) {
				if (!rspamd_symbols_cache_check_deps (task, cache, item,
						checkpoint)) {
					break;
				}

				rspamd_symbols_cache_check_symbol (task, cache, item,
						checkpoint, &total_microseconds);
			}

			if (total_microseconds > max_microseconds) {
				/* Maybe we should stop and check pending events? */
				if (rspamd_session_events_pending (task->s) >
						start_events_pending) {
					msg_debug_task ("trying to check async events after spending "
							"%d microseconds processing symbols",
							(gint)total_microseconds);
					return TRUE;
				}
			}
		}
	}

	return TRUE;
}

struct counters_cbdata {
	ucl_object_t *top;
	struct symbols_cache *cache;
};

static void
rspamd_symbols_cache_counters_cb (gpointer v, gpointer ud)
{
	struct counters_cbdata *cbd = ud;
	ucl_object_t *obj, *top;
	struct cache_item *item = v, *parent;

	top = cbd->top;

	if (!(item->type & SYMBOL_TYPE_CALLBACK)) {
		obj = ucl_object_typed_new (UCL_OBJECT);
		ucl_object_insert_key (obj, ucl_object_fromstring (item->symbol),
				"symbol", 0, false);

		if ((item->type & SYMBOL_TYPE_VIRTUAL) && item->parent != -1) {
			g_assert (item->parent < (gint)cbd->cache->items_by_id->len);
			parent = g_ptr_array_index (cbd->cache->items_by_id,
					item->parent);
			ucl_object_insert_key (obj, ucl_object_fromdouble (item->weight),
					"weight", 0, false);
			ucl_object_insert_key (obj, ucl_object_fromint (item->frequency),
					"frequency", 0, false);
			ucl_object_insert_key (obj, ucl_object_fromdouble (parent->avg_time),
					"time", 0, false);
		}
		else {
			ucl_object_insert_key (obj, ucl_object_fromdouble (item->weight),
					"weight", 0, false);
			ucl_object_insert_key (obj, ucl_object_fromint (item->frequency),
					"frequency", 0, false);
			ucl_object_insert_key (obj, ucl_object_fromdouble (item->avg_time),
					"time", 0, false);
		}

		ucl_array_append (top, obj);
	}
}

ucl_object_t *
rspamd_symbols_cache_counters (struct symbols_cache * cache)
{
	ucl_object_t *top;
	struct counters_cbdata cbd;

	g_assert (cache != NULL);
	top = ucl_object_typed_new (UCL_ARRAY);
	cbd.top = top;
	cbd.cache = cache;
	g_ptr_array_foreach (cache->items_by_order->d,
			rspamd_symbols_cache_counters_cb, &cbd);

	return top;
}

static void
rspamd_symbols_cache_resort_cb (gint fd, short what, gpointer ud)
{
	struct timeval tv;
	gdouble tm;
	struct symbols_cache *cache = ud;
	struct cache_item *item, *parent;
	guint i;

	/* Plan new event */
	tm = rspamd_time_jitter (cache->reload_time, 0);
	msg_debug_cache ("resort symbols cache, next reload in %.2f seconds", tm);
	g_assert (cache != NULL);
	evtimer_set (&cache->resort_ev, rspamd_symbols_cache_resort_cb, cache);
	double_to_tv (tm, &tv);
	event_add (&cache->resort_ev, &tv);

	rspamd_mempool_lock_mutex (cache->mtx);

	/* Gather stats from shared execution times */
	for (i = 0; i < cache->items_by_id->len; i ++) {
		item = g_ptr_array_index (cache->items_by_id, i);

		if (item->type & (SYMBOL_TYPE_CALLBACK|SYMBOL_TYPE_NORMAL)) {
			if (item->cd->number > 0) {
				item->avg_counter += item->cd->number + 1;
				item->avg_time = item->avg_time +
						(item->cd->value - item->avg_time) /
								(gdouble)item->avg_counter;
				item->cd->value = item->avg_time;
				item->cd->number = item->avg_counter;
			}
		}
	}
	/* Sync virtual symbols */
	for (i = 0; i < cache->items_by_id->len; i ++) {
		item = g_ptr_array_index (cache->items_by_id, i);

		if (item->parent != -1) {
			parent = g_ptr_array_index (cache->items_by_id, item->parent);

			if (parent) {
				item->avg_time = parent->avg_time;
				item->avg_counter = parent->avg_counter;
			}
		}
	}

	rspamd_mempool_unlock_mutex (cache->mtx);

	rspamd_symbols_cache_resort (cache);
}

void
rspamd_symbols_cache_start_refresh (struct symbols_cache * cache,
		struct event_base *ev_base)
{
	struct timeval tv;
	gdouble tm;

	tm = rspamd_time_jitter (cache->reload_time, 0);
	g_assert (cache != NULL);
	evtimer_set (&cache->resort_ev, rspamd_symbols_cache_resort_cb, cache);
	event_base_set (ev_base, &cache->resort_ev);
	double_to_tv (tm, &tv);
	event_add (&cache->resort_ev, &tv);
}

void
rspamd_symbols_cache_inc_frequency (struct symbols_cache *cache,
		const gchar *symbol)
{
	struct cache_item *item, *parent;

	g_assert (cache != NULL);

	item = g_hash_table_lookup (cache->items_by_symbol, symbol);

	if (item != NULL) {
		/* We assume ++ as atomic op */
		item->frequency ++;
		cache->total_freq ++;

		/* For virtual symbols we also increase counter for parent */
		if (item->parent != -1) {
			parent = g_ptr_array_index (cache->items_by_id, item->parent);
			parent->frequency ++;
		}
	}
}

void
rspamd_symbols_cache_add_dependency (struct symbols_cache *cache,
		gint id_from, const gchar *to)
{
	struct cache_item *source;
	struct cache_dependency *dep;

	g_assert (id_from < (gint)cache->items_by_id->len);

	source = g_ptr_array_index (cache->items_by_id, id_from);
	dep = rspamd_mempool_alloc (cache->static_pool, sizeof (*dep));
	dep->id = id_from;
	dep->sym = rspamd_mempool_strdup (cache->static_pool, to);
	/* Will be filled later */
	dep->item = NULL;
	g_ptr_array_add (source->deps, dep);
}

void
rspamd_symbols_cache_add_delayed_dependency (struct symbols_cache *cache,
		const gchar *from, const gchar *to)
{
	struct delayed_cache_dependency *ddep;

	g_assert (from != NULL);
	g_assert (to != NULL);

	ddep = g_slice_alloc (sizeof (*ddep));
	ddep->from = g_strdup (from);
	ddep->to = g_strdup (to);

	cache->delayed_deps = g_list_prepend (cache->delayed_deps, ddep);
}

gint
rspamd_symbols_cache_find_symbol (struct symbols_cache *cache, const gchar *name)
{
	struct cache_item *item;

	g_assert (cache != NULL);

	if (name == NULL) {
		return -1;
	}

	item = g_hash_table_lookup (cache->items_by_symbol, name);

	if (item != NULL) {
		return item->id;
	}

	return -1;
}

static gint
rspamd_symbols_cache_find_symbol_parent (struct symbols_cache *cache,
		const gchar *name)
{
	struct cache_item *item;

	g_assert (cache != NULL);

	if (name == NULL) {
		return -1;
	}

	item = g_hash_table_lookup (cache->items_by_symbol, name);

	if (item != NULL) {

		while (item != NULL && item->parent != -1) {
			item = g_ptr_array_index (cache->items_by_id, item->parent);
		}

		return item ? item->id : -1;
	}

	return -1;
}

const gchar *
rspamd_symbols_cache_symbol_by_id (struct symbols_cache *cache,
		gint id)
{
	struct cache_item *item;

	g_assert (cache != NULL);

	if (id < 0 || id >= (gint)cache->items_by_id->len) {
		return NULL;
	}

	item = g_ptr_array_index (cache->items_by_id, id);

	return item->symbol;
}

guint
rspamd_symbols_cache_symbols_count (struct symbols_cache *cache)
{
	g_assert (cache != NULL);

	return cache->items_by_id->len;
}

static void
rspamd_symbols_cache_disable_all_symbols (struct rspamd_task *task,
		struct symbols_cache *cache)
{
	struct cache_savepoint *checkpoint;

	if (task->checkpoint == NULL) {
		checkpoint = rspamd_symbols_cache_make_checkpoint (task, cache);
		task->checkpoint = checkpoint;
	}
	else {
		checkpoint = task->checkpoint;
	}

	/* Set all symbols as started + finished to disable their execution */
	memset (checkpoint->processed_bits, 0xff,
			NBYTES (cache->used_items) * 2);
}

void
rspamd_symbols_cache_disable_symbol (struct rspamd_task *task,
		struct symbols_cache *cache, const gchar *symbol)
{
	struct cache_savepoint *checkpoint;
	struct cache_item *item;
	gint id;

	if (task->checkpoint == NULL) {
		checkpoint = rspamd_symbols_cache_make_checkpoint (task, cache);
		task->checkpoint = checkpoint;
	}
	else {
		checkpoint = task->checkpoint;
	}

	id = rspamd_symbols_cache_find_symbol_parent (cache, symbol);

	if (id > 0) {
		/* Set executed and finished flags */
		item = g_ptr_array_index (cache->items_by_id, id);

		setbit (checkpoint->processed_bits, item->id * 2);
		setbit (checkpoint->processed_bits, item->id * 2 + 1);

		msg_debug_task ("disable execution of %s", symbol);
	}
	else {
		msg_info_task ("cannot disable %s: not found", symbol);
	}
}

static void
rspamd_symbols_cache_enable_symbol (struct rspamd_task *task,
		struct symbols_cache *cache, const gchar *symbol)
{
	struct cache_savepoint *checkpoint;
	struct cache_item *item;
	gint id;

	if (task->checkpoint == NULL) {
		checkpoint = rspamd_symbols_cache_make_checkpoint (task, cache);
		task->checkpoint = checkpoint;
	}
	else {
		checkpoint = task->checkpoint;
	}

	id = rspamd_symbols_cache_find_symbol_parent (cache, symbol);

	if (id > 0) {
		/* Set executed and finished flags */
		item = g_ptr_array_index (cache->items_by_id, id);

		clrbit (checkpoint->processed_bits, item->id * 2);
		clrbit (checkpoint->processed_bits, item->id * 2 + 1);

		msg_debug_task ("enable execution of %s", symbol);
	}
	else {
		msg_info_task ("cannot enable %s: not found", symbol);
	}
}

struct rspamd_abstract_callback_data* rspamd_symbols_cache_get_cbdata (
		struct symbols_cache *cache, const gchar *symbol)
{
	gint id;
	struct cache_item *item;

	g_assert (cache != NULL);
	g_assert (symbol != NULL);

	id = rspamd_symbols_cache_find_symbol_parent (cache, symbol);

	if (id < 0) {
		return NULL;
	}

	item = g_ptr_array_index (cache->items_by_id, id);

	return item->user_data;
}

gboolean
rspamd_symbols_cache_set_cbdata (struct symbols_cache *cache,
		const gchar *symbol, struct rspamd_abstract_callback_data *cbdata)
{
	gint id;
	struct cache_item *item;

	g_assert (cache != NULL);
	g_assert (symbol != NULL);

	id = rspamd_symbols_cache_find_symbol_parent (cache, symbol);

	if (id < 0) {
		return FALSE;
	}

	item = g_ptr_array_index (cache->items_by_id, id);
	item->user_data = cbdata;

	return TRUE;
}