/*-
 * 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 "rspamd.h"
#include "shingles.h"
#include "ottery.h"
#include "libserver/word.h"
#include <math.h>

static const char *
algorithm_to_string(enum rspamd_shingle_alg alg)
{
	const char *ret = "unknown";

	switch (alg) {
	case RSPAMD_SHINGLES_OLD:
		ret = "siphash";
		break;
	case RSPAMD_SHINGLES_XXHASH:
		ret = "xxhash";
		break;
	case RSPAMD_SHINGLES_MUMHASH:
		ret = "mumhash";
		break;
	case RSPAMD_SHINGLES_FAST:
		ret = "fasthash";
		break;
	}

	return ret;
}

static void
generate_random_string(char *begin, size_t len)
{
	gsize i;

	for (i = 0; i < len; i++) {
		begin[i] = ottery_rand_range('z' - 'a') + 'a';
	}
}

static rspamd_words_t *
generate_fuzzy_words(gsize cnt, gsize max_len)
{
	rspamd_words_t *res;
	gsize i, wlen;
	rspamd_word_t word;
	char *t;

	res = g_malloc(sizeof(*res));
	kv_init(*res);

	for (i = 0; i < cnt; i++) {
		wlen = ottery_rand_range(max_len) + 1;
		/* wlen = max_len; */

		t = g_malloc(wlen);
		generate_random_string(t, wlen);

		memset(&word, 0, sizeof(word));
		word.stemmed.begin = t;
		word.stemmed.len = wlen;
		word.original.begin = t;
		word.original.len = wlen;
		word.flags = 0; /* No flags set, so it won't be skipped */

		kv_push(rspamd_word_t, *res, word);
	}

	return res;
}

static void
permute_vector(rspamd_words_t *in, double prob)
{
	gsize i, total = 0;
	rspamd_word_t *w;

	for (i = 0; i < kv_size(*in); i++) {
		if (ottery_rand_unsigned() <= G_MAXUINT * prob) {
			w = &kv_A(*in, i);
			generate_random_string((char *) w->stemmed.begin, w->stemmed.len);
			/* Also update original since they point to same memory */
			w->original.begin = w->stemmed.begin;
			w->original.len = w->stemmed.len;
			total++;
		}
	}
	msg_debug("generated %z permutations of %ud words", total, (unsigned int) kv_size(*in));
}

static void
free_fuzzy_words(rspamd_words_t *ar)
{
	gsize i;
	rspamd_word_t *w;

	for (i = 0; i < kv_size(*ar); i++) {
		w = &kv_A(*ar, i);
		g_free((gpointer) w->stemmed.begin);
	}

	kv_destroy(*ar);
	g_free(ar);
}

static void
test_case(gsize cnt, gsize max_len, double perm_factor,
		  enum rspamd_shingle_alg alg)
{
	rspamd_words_t *input;
	struct rspamd_shingle *sgl, *sgl_permuted;
	double res;
	unsigned char key[16];
	double ts1, ts2;

	ottery_rand_bytes(key, sizeof(key));
	input = generate_fuzzy_words(cnt, max_len);
	ts1 = rspamd_get_virtual_ticks();
	sgl = rspamd_shingles_from_text(input, key, NULL,
									rspamd_shingles_default_filter, NULL, alg);
	ts2 = rspamd_get_virtual_ticks();
	permute_vector(input, perm_factor);
	sgl_permuted = rspamd_shingles_from_text(input, key, NULL,
											 rspamd_shingles_default_filter, NULL, alg);

	res = rspamd_shingles_compare(sgl, sgl_permuted);

	msg_info("%s (%z words of %z max len, %.2f perm factor):"
			 " percentage of common shingles: %.3f, generate time: %.4f sec",
			 algorithm_to_string(alg), cnt, max_len, perm_factor, res, ts2 - ts1);
	//g_assert_cmpfloat (fabs ((1.0 - res) - sqrt (perm_factor)), <=, 0.25);

	free_fuzzy_words(input);
	g_free(sgl);
	g_free(sgl_permuted);
}

static const uint64_t expected_old[RSPAMD_SHINGLE_SIZE] = {
	0x2a97e024235cedc5,
	0x46238acbcc55e9e0,
	0x2378ff151af075b3,
	0xde1f29a95cad109,
	0x5d3bbbdb5db5d19f,
	0x4d75a0ec52af10a6,
	0x215ecd6372e755b5,
	0x7b52295758295350,
	0x17387d1beddc7f62,
	0x26264ca879ffcada,
	0x49d4a65ec0ab9914,
	0xa2763e6995350cf,
	0x3f4570231449c13f,
	0x3309f857a0e54ee5,
	0x24e4c5b561b0fce3,
	0x1f153e3b275bfd1b,
	0x4d067dbc97c3fd78,
	0x9ffa2d076fa4f8bc,
	0x3d8907f84b9ffc6c,
	0x1cfd664c5262d256,
	0xcdd7e744b699c15,
	0x5544a2bbe05124f7,
	0x5a4029b5d6a06f7,
	0xd5adfbdc756c0e4,
	0xa504b23d9689a67e,
	0x15d945f7007de115,
	0xbf676c0522a2c51d,
	0x1c8d8163ad4b0f93,
	0xa2c4ba20799344d7,
	0x27c6f13c02134388,
	0xa1d443d31fd5a3,
	0x99fbca9f8563080,
};

static const uint64_t expected_xxhash[RSPAMD_SHINGLE_SIZE] = {
	0x33b134be11a705a,
	0x36e2ea657aa36903,
	0x6547b57f7470ce9d,
	0x8253eb6d2f8f158e,
	0x1cc99e3cf22388f,
	0x2396da27ea36ffe8,
	0x1b457d208ad3d96c,
	0x2d6ac733d7a2c107,
	0x17849cbed75cc4d1,
	0x4dd94e772330e804,
	0x39f592fa32014ed4,
	0xa2f6229ad356461,
	0x6dc825879a057b37,
	0x886b12cef4338b05,
	0x8b23af68c186518a,
	0x16932b40339aaf02,
	0x412090c6bb0b719c,
	0x4d4a88cbdf1935f3,
	0x233bcbddb5f67a7,
	0x474719442a33dcca,
	0x2da7ec30563e622,
	0x7ab90086960e1ad2,
	0x3ea2b45582539f75,
	0x108cd9287d95a6c5,
	0x69ba7c67c115597,
	0x10880860eb75e982,
	0x16f3d90e6ab995a6,
	0x5f24ea09379b9f5c,
	0x3c2dc04088e8fe54,
	0x340b8cf1c6f1227,
	0x193bc348ed2e9ce7,
	0x68454ef43da9c748,
};

static const uint64_t expected_mumhash[RSPAMD_SHINGLE_SIZE] = {
	0x38d35473b80a7fc3,
	0x1300531adc2d16a1,
	0x26883bc89f78f4bd,
	0x57de365ef6d1a62,
	0x773603185fcbb20a,
	0x39c6cbd7ebbeaa88,
	0x676c7445ad167e70,
	0x432315d1ecc4c0b1,
	0x1380b95756dbb078,
	0x9ee12832fa53b90e,
	0x72970be210f0dd0b,
	0x62909bd520f5956,
	0x66196965a45eb32a,
	0x2466a9ca5436620e,
	0x157b828b10e10f6e,
	0x429bb673a523a7e5,
	0x51a6ace94f320f88,
	0x23f53a30bd7d7147,
	0xbee557664d3bc34c,
	0x65730c88cd212a9,
	0x87e72c0cd05fd0e,
	0x417a744669baeb3d,
	0x78e26f7917829324,
	0x439777dcfc25fdf4,
	0x582eac6ff013f00b,
	0x1e40aa90e367f4af,
	0x301d14a28d6c23a2,
	0x34140ecb21b6c69,
	0x390a091c8b4c31b9,
	0x2e35fecf9fff0ae7,
	0x94322e1a5cf31f1b,
	0x33cb9190905e049a,
};

static const uint64_t expected_fasthash[RSPAMD_SHINGLE_SIZE] = {
	0x3843a716f94828a6,
	0x13fd5386dda3b28d,
	0x71cb09de527c40a,
	0x5d6f59ffd839c62,
	0x7ce3633acd568476,
	0x9014298cbd00167,
	0x6708ec29eedb5350,
	0x2882931ff2c5c410,
	0x1839d8b947b12571,
	0x58f7bc3829173302,
	0x4dac8103da51abc4,
	0x6c5cbcc6fb1de28,
	0x31fefcef9bafb755,
	0x6f2d1a0b1feca401,
	0x3e71f3718e520b06,
	0x42f6ba11164ab231,
	0x21164d010bd76f4a,
	0x4c597ccc7b60f620,
	0x2cf1ca3383b77574,
	0x54ff9c01660b8add,
	0x2ca344758f40380d,
	0x1b962321bd37d0f2,
	0x9323bb99c32bc418,
	0x375659d0eef2b8f2,
	0x1dbd23a1030084b7,
	0x83cb978dee06aa0a,
	0x42c97be5b27a7763,
	0x3b6d6b7270ed765,
	0x125c12fdba584aed,
	0x1c826397afe58763,
	0x8bdbe2d43f3eda96,
	0x954cda70edf6591f,
};

void rspamd_shingles_test_func(void)
{
	enum rspamd_shingle_alg alg = RSPAMD_SHINGLES_OLD;
	struct rspamd_shingle *sgl;
	unsigned char key[16];
	rspamd_words_t input;
	rspamd_word_t word;
	int i;

	memset(key, 0, sizeof(key));
	kv_init(input);

	for (i = 0; i < 5; i++) {
		char *b = g_alloca(8);
		memset(b, 0, 8);
		memcpy(b + 1, "test", 4);
		b[0] = 'a' + i;

		memset(&word, 0, sizeof(word));
		word.stemmed.begin = b;
		word.stemmed.len = 5 + ((i + 1) % 4);
		word.original.begin = b;
		word.original.len = word.stemmed.len;
		word.flags = 0; /* No flags set, so it won't be skipped */

		kv_push(rspamd_word_t, input, word);
	}

	sgl = rspamd_shingles_from_text(&input, key, NULL,
									rspamd_shingles_default_filter, NULL, RSPAMD_SHINGLES_OLD);
	for (i = 0; i < RSPAMD_SHINGLE_SIZE; i++) {
		g_assert(sgl->hashes[i] == expected_old[i]);
	}
	g_free(sgl);

	sgl = rspamd_shingles_from_text(&input, key, NULL,
									rspamd_shingles_default_filter, NULL, RSPAMD_SHINGLES_XXHASH);
	for (i = 0; i < RSPAMD_SHINGLE_SIZE; i++) {
		g_assert(sgl->hashes[i] == expected_xxhash[i]);
	}
	g_free(sgl);

	sgl = rspamd_shingles_from_text(&input, key, NULL,
									rspamd_shingles_default_filter, NULL, RSPAMD_SHINGLES_MUMHASH);
	for (i = 0; i < RSPAMD_SHINGLE_SIZE; i++) {
		g_assert(sgl->hashes[i] == expected_mumhash[i]);
	}
	g_free(sgl);

	sgl = rspamd_shingles_from_text(&input, key, NULL,
									rspamd_shingles_default_filter, NULL, RSPAMD_SHINGLES_FAST);
	for (i = 0; i < RSPAMD_SHINGLE_SIZE; i++) {
		g_assert(sgl->hashes[i] == expected_fasthash[i]);
	}
	g_free(sgl);

	kv_destroy(input);

	for (alg = RSPAMD_SHINGLES_OLD; alg <= RSPAMD_SHINGLES_FAST; alg++) {
		test_case(200, 10, 0.1, alg);
		test_case(500, 20, 0.01, alg);
		test_case(5000, 20, 0.01, alg);
		test_case(5000, 15, 0, alg);
		test_case(5000, 30, 1.0, alg);
		test_case(50000, 30, 0.02, alg);
		test_case(50000, 5, 0.02, alg);
		test_case(50000, 16, 0.02, alg);
	}
}
