/* Copyright (c) 2015, Vsevolod Stakhov
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *       * Redistributions of source code must retain the above copyright
 *         notice, this list of conditions and the following disclaimer.
 *       * Redistributions in binary form must reproduce the above copyright
 *         notice, this list of conditions and the following disclaimer in the
 *         documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED ''AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL AUTHOR BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "config.h"
#include "learn_cache.h"
#include "rspamd.h"
#include "stat_api.h"
#include "stat_internal.h"
#include "cryptobox.h"
#include "ucl.h"
#include "fstring.h"
#include "message.h"
#include "libutil/sqlite_utils.h"

static const char *create_tables_sql =
		""
		"CREATE TABLE IF NOT EXISTS learns("
		"id INTEGER PRIMARY KEY,"
		"flag INTEGER NOT NULL,"
		"digest TEXT NOT NULL);"
		"CREATE UNIQUE INDEX IF NOT EXISTS d ON learns(digest);"
		"";

#define SQLITE_CACHE_PATH RSPAMD_DBDIR "/learn_cache.sqlite"

enum rspamd_stat_sqlite3_stmt_idx {
	RSPAMD_STAT_CACHE_TRANSACTION_START_IM = 0,
	RSPAMD_STAT_CACHE_TRANSACTION_START_DEF,
	RSPAMD_STAT_CACHE_TRANSACTION_COMMIT,
	RSPAMD_STAT_CACHE_TRANSACTION_ROLLBACK,
	RSPAMD_STAT_CACHE_GET_LEARN,
	RSPAMD_STAT_CACHE_ADD_LEARN,
	RSPAMD_STAT_CACHE_UPDATE_LEARN,
	RSPAMD_STAT_CACHE_MAX
};

static struct rspamd_sqlite3_prstmt prepared_stmts[RSPAMD_STAT_CACHE_MAX] =
{
	{
		.idx = RSPAMD_STAT_CACHE_TRANSACTION_START_IM,
		.sql = "BEGIN IMMEDIATE TRANSACTION;",
		.args = "",
		.stmt = NULL,
		.result = SQLITE_DONE,
		.ret = ""
	},
	{
		.idx = RSPAMD_STAT_CACHE_TRANSACTION_START_DEF,
		.sql = "BEGIN DEFERRED TRANSACTION;",
		.args = "",
		.stmt = NULL,
		.result = SQLITE_DONE,
		.ret = ""
	},
	{
		.idx = RSPAMD_STAT_CACHE_TRANSACTION_COMMIT,
		.sql = "COMMIT;",
		.args = "",
		.stmt = NULL,
		.result = SQLITE_DONE,
		.ret = ""
	},
	{
		.idx = RSPAMD_STAT_CACHE_TRANSACTION_ROLLBACK,
		.sql = "ROLLBACK;",
		.args = "",
		.stmt = NULL,
		.result = SQLITE_DONE,
		.ret = ""
	},
	{
		.idx = RSPAMD_STAT_CACHE_GET_LEARN,
		.sql = "SELECT flag FROM learns WHERE digest=?1",
		.args = "V",
		.stmt = NULL,
		.result = SQLITE_ROW,
		.ret = "I"
	},
	{
		.idx = RSPAMD_STAT_CACHE_ADD_LEARN,
		.sql = "INSERT INTO learns(digest, flag) VALUES (?1, ?2);",
		.args = "VI",
		.stmt = NULL,
		.result = SQLITE_DONE,
		.ret = ""
	},
	{
		.idx = RSPAMD_STAT_CACHE_UPDATE_LEARN,
		.sql = "UPDATE learns SET flag=?1 WHERE digest=?2;",
		.args = "IV",
		.stmt = NULL,
		.result = SQLITE_DONE,
		.ret = ""
	}
};

struct rspamd_stat_sqlite3_ctx {
	sqlite3 *db;
	GArray *prstmt;
};

gpointer
rspamd_stat_cache_sqlite3_init (struct rspamd_stat_ctx *ctx,
		struct rspamd_config *cfg,
		struct rspamd_statfile *st,
		const ucl_object_t *cf)
{
	struct rspamd_stat_sqlite3_ctx *new = NULL;
	const ucl_object_t *elt;
	gchar dbpath[PATH_MAX];
	const gchar *path = SQLITE_CACHE_PATH;
	sqlite3 *sqlite;
	GError *err = NULL;


	if (cf) {
		elt = ucl_object_find_key (cf, "path");

		if (elt != NULL) {
			path = ucl_object_tostring (elt);
		}
	}

	rspamd_snprintf (dbpath, sizeof (dbpath), "%s", path);

	sqlite = rspamd_sqlite3_open_or_create (cfg->cfg_pool,
			dbpath, create_tables_sql, &err);

	if (sqlite == NULL) {
		msg_err ("cannot open sqlite3 cache: %e", err);
		g_error_free (err);
		err = NULL;
	}
	else {
		new = g_slice_alloc (sizeof (*new));
		new->db = sqlite;
		new->prstmt = rspamd_sqlite3_init_prstmt (sqlite, prepared_stmts,
				RSPAMD_STAT_CACHE_MAX, &err);

		if (new->prstmt == NULL) {
			msg_err ("cannot open sqlite3 cache: %e", err);
			g_error_free (err);
			err = NULL;
			sqlite3_close (sqlite);
			g_slice_free1 (sizeof (*new), new);
			new = NULL;
		}
	}

	return new;
}

static rspamd_learn_t
rspamd_stat_cache_sqlite3_check (rspamd_mempool_t *pool,
		const guchar *h, gsize len, gboolean is_spam,
		struct rspamd_stat_sqlite3_ctx *ctx)
{
	gint rc, ret = RSPAMD_LEARN_OK;
	gint64 flag;

	rspamd_sqlite3_run_prstmt (pool, ctx->db, ctx->prstmt,
			RSPAMD_STAT_CACHE_TRANSACTION_START_DEF);
	rc = rspamd_sqlite3_run_prstmt (pool, ctx->db, ctx->prstmt,
			RSPAMD_STAT_CACHE_GET_LEARN, (gint64)len, h, &flag);
	rspamd_sqlite3_run_prstmt (pool, ctx->db, ctx->prstmt,
			RSPAMD_STAT_CACHE_TRANSACTION_COMMIT);


	if (rc == SQLITE_OK) {
		/* We have some existing record in the table */
		if (!!flag == !!is_spam) {
			/* Already learned */

			ret = RSPAMD_LEARN_INGORE;
		}
		else {
			/* Need to relearn */
			flag = !!is_spam ? 1 : 0;

			rspamd_sqlite3_run_prstmt (pool, ctx->db, ctx->prstmt,
					RSPAMD_STAT_CACHE_TRANSACTION_START_IM);
			rc = rspamd_sqlite3_run_prstmt (pool, ctx->db, ctx->prstmt,
					RSPAMD_STAT_CACHE_UPDATE_LEARN, flag, (gint64)len, h);
			rspamd_sqlite3_run_prstmt (pool, ctx->db, ctx->prstmt,
					RSPAMD_STAT_CACHE_TRANSACTION_COMMIT);

			return RSPAMD_LEARN_UNLEARN;
		}
	}
	else {
		/* Insert result new id */
		flag = !!is_spam ? 1 : 0;
		rspamd_sqlite3_run_prstmt (pool, ctx->db, ctx->prstmt,
				RSPAMD_STAT_CACHE_TRANSACTION_START_IM);
		rspamd_sqlite3_run_prstmt (pool, ctx->db, ctx->prstmt,
				RSPAMD_STAT_CACHE_ADD_LEARN, (gint64)len, h, flag);
		rspamd_sqlite3_run_prstmt (pool, ctx->db, ctx->prstmt,
				RSPAMD_STAT_CACHE_TRANSACTION_COMMIT);
	}

	return ret;
}

gint
rspamd_stat_cache_sqlite3_process (struct rspamd_task *task,
		gboolean is_spam, gpointer c)
{
	struct rspamd_stat_sqlite3_ctx *ctx = (struct rspamd_stat_sqlite3_ctx *)c;
	struct mime_text_part *part;
	rspamd_cryptobox_hash_state_t st;
	rspamd_ftok_t *word;
	guchar out[rspamd_cryptobox_HASHBYTES];
	guint i, j;

	if (ctx != NULL && ctx->db != NULL) {
		rspamd_cryptobox_hash_init (&st, NULL, 0);

		for (i = 0; i < task->text_parts->len; i ++) {
			part = g_ptr_array_index (task->text_parts, i);

			if (part->normalized_words != NULL) {
				for (j = 0; j < part->normalized_words->len; j ++) {
					word = &g_array_index (part->normalized_words, rspamd_ftok_t, j);
					rspamd_cryptobox_hash_update (&st, word->begin, word->len);
				}
			}
		}

		rspamd_cryptobox_hash_final (&st, out);

		return rspamd_stat_cache_sqlite3_check (task->task_pool,
				out, sizeof (out), is_spam, ctx);
	}

	return RSPAMD_LEARN_OK;
}

void
rspamd_stat_cache_sqlite3_close (gpointer c)
{
	struct rspamd_stat_sqlite3_ctx *ctx = (struct rspamd_stat_sqlite3_ctx *)c;

	if (ctx != NULL) {
		rspamd_sqlite3_close_prstmt (ctx->db, ctx->prstmt);
		sqlite3_close (ctx->db);
		g_slice_free1 (sizeof (*ctx), ctx);
	}

}