/* 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 "lua_common.h"
#include "task.h"
#include "rspamd.h"
#include "html.h"
#include "cfg_rcl.h"
#include "tokenizers/tokenizers.h"
#include "libserver/url.h"
#include <math.h>
#include <glob.h>

/***
 * @module rspamd_util
 * This module contains some generic purpose utilities that could be useful for
 * testing and production rules.
 */

/***
 * @function util.create_event_base()
 * Creates new event base for processing asynchronous events
 * @return {ev_base} new event processing base
 */
LUA_FUNCTION_DEF (util, create_event_base);
/***
 * @function util.load_rspamd_config(filename)
 * Load rspamd config from the specified file
 * @return {confg} new configuration object suitable for access
 */
LUA_FUNCTION_DEF (util, load_rspamd_config);
/***
 * @function util.config_from_ucl(any)
 * Load rspamd config from ucl reperesented by any lua table
 * @return {confg} new configuration object suitable for access
 */
LUA_FUNCTION_DEF (util, config_from_ucl);
/***
 * @function util.encode_base64(input[, str_len])
 * Encodes data in base64 breaking lines if needed
 * @param {text or string} input input data
 * @param {number} str_len optional size of lines or 0 if split is not needed
 * @return {rspamd_text} encoded data chunk
 */
LUA_FUNCTION_DEF (util, encode_base64);
/***
 * @function util.decode_base64(input)
 * Decodes data from base64 ignoring whitespace characters
 * @param {text or string} input data to decode; if `rspamd{text}` is used then the string is modified **in-place**
 * @return {rspamd_text} decoded data chunk
 */
LUA_FUNCTION_DEF (util, decode_base64);
/***
 * @function util.tokenize_text(input[, exceptions])
 * Create tokens from a text using optional exceptions list
 * @param {text/string} input input data
 * @param {table} exceptions, a table of pairs containing <start_pos,lenght> of exceptions in the input
 * @return {table/strings} list of strings representing words in the text
 */
LUA_FUNCTION_DEF (util, tokenize_text);
LUA_FUNCTION_DEF (util, process_message);
/***
 * @function util.tanh(num)
 * Calculates hyperbolic tanhent of the specified floating point value
 * @param {number} num input number
 * @return {number} hyperbolic tanhent of the variable
 */
LUA_FUNCTION_DEF (util, tanh);

/***
 * @function util.parse_html(input)
 * Parses HTML and returns the according text
 * @param {string|text} in input HTML
 * @return {rspamd_text} processed text with no HTML tags
 */
LUA_FUNCTION_DEF (util, parse_html);

/***
 * @function util.levenshtein_distance(s1, s2)
 * Returns levenstein distance between two strings
 * @param {string} s1 the first string
 * @param {string} s2 the second string
 * @return {number} number of differences in two strings
 */
LUA_FUNCTION_DEF (util, levenshtein_distance);

/***
 * @function util.parse_addr(str)
 * Parse rfc822 address to components. Returns a table of components:
 *
 * - `name`: name of address (e.g. Some User)
 * - `addr`: address part (e.g. user@example.com)
 *
 * @param {string} str input string
 * @return {table} resulting table of components
 */
LUA_FUNCTION_DEF (util, parse_addr);

/***
 * @function util.fold_header(name, value)
 * Fold rfc822 header according to the folding rules
 *
 * @param {string} name name of the header
 * @param {string} value value of the header
 * @return {string} Folded value of the header
 */
LUA_FUNCTION_DEF (util, fold_header);

/***
 * @function util.is_uppercase(str)
 * Returns true if a string is all uppercase
 *
 * @param {string} str input string
 * @return {bool} true if a string is all uppercase
 */
LUA_FUNCTION_DEF (util, is_uppercase);

/**
 * @function util.humanize_number(num)
 * Returns humanized representation of given number (like 1k instead of 1000)
 *
 * @param {number} num number to humanize
 * @return {string} humanized representation of a number
 */
LUA_FUNCTION_DEF (util, humanize_number);

/**
 * @function util.get_tld(host)
 * Returns tld for the specified host
 *
 * @param {string} host hostname
 * @return {string} tld part of hostname or the full hostname
 */
LUA_FUNCTION_DEF (util, get_tld);

/**
 * @function util.glob(pattern)
 * Returns results for the glob match for the specified pattern
 *
 * @param {string} pattern glob pattern to match ('?' and '*' are supported)
 * @return {table/string} list of matched files
 */
LUA_FUNCTION_DEF (util, glob);

/**
 * @function util.parse_mail_address(str)
 * Parses email address and returns a table of tables in the following format:
 *
 * - `name` - name of internet address in UTF8, e.g. for `Vsevolod Stakhov <blah@foo.com>` it returns `Vsevolod Stakhov`
 * - `addr` - address part of the address
 * - `user` - user part (if present) of the address, e.g. `blah`
 * - `domain` - domain part (if present), e.g. `foo.com`
 *
 * @param {string} str input string
 * @return {table/tables} parsed list of mail addresses
 */
LUA_FUNCTION_DEF (util, parse_mail_address);

static const struct luaL_reg utillib_f[] = {
	LUA_INTERFACE_DEF (util, create_event_base),
	LUA_INTERFACE_DEF (util, load_rspamd_config),
	LUA_INTERFACE_DEF (util, config_from_ucl),
	LUA_INTERFACE_DEF (util, process_message),
	LUA_INTERFACE_DEF (util, encode_base64),
	LUA_INTERFACE_DEF (util, decode_base64),
	LUA_INTERFACE_DEF (util, tokenize_text),
	LUA_INTERFACE_DEF (util, tanh),
	LUA_INTERFACE_DEF (util, parse_html),
	LUA_INTERFACE_DEF (util, levenshtein_distance),
	LUA_INTERFACE_DEF (util, parse_addr),
	LUA_INTERFACE_DEF (util, fold_header),
	LUA_INTERFACE_DEF (util, is_uppercase),
	LUA_INTERFACE_DEF (util, humanize_number),
	LUA_INTERFACE_DEF (util, get_tld),
	LUA_INTERFACE_DEF (util, glob),
	LUA_INTERFACE_DEF (util, parse_mail_address),
	{NULL, NULL}
};

static gint
lua_util_create_event_base (lua_State *L)
{
	struct event_base **pev_base;

	pev_base = lua_newuserdata (L, sizeof (struct event_base *));
	rspamd_lua_setclass (L, "rspamd{ev_base}", -1);
	*pev_base = event_init ();

	return 1;
}

static gint
lua_util_load_rspamd_config (lua_State *L)
{
	struct rspamd_config *cfg, **pcfg;
	const gchar *cfg_name;

	cfg_name = luaL_checkstring (L, 1);

	if (cfg_name) {
		cfg = rspamd_config_new ();

		if (rspamd_config_read (cfg, cfg_name, NULL, NULL, NULL, NULL)) {
			msg_err_config ("cannot load config from %s", cfg_name);
			lua_pushnil (L);
		}
		else {
			rspamd_config_post_load (cfg, FALSE);
			pcfg = lua_newuserdata (L, sizeof (struct rspamd_config *));
			rspamd_lua_setclass (L, "rspamd{config}", -1);
			*pcfg = cfg;
		}
	}

	return 1;
}

static gint
lua_util_config_from_ucl (lua_State *L)
{
	struct rspamd_config *cfg, **pcfg;
	struct rspamd_rcl_section *top;
	GError *err = NULL;
	ucl_object_t *obj;

	obj = ucl_object_lua_import (L, 1);

	if (obj) {
		cfg = g_malloc0 (sizeof (struct rspamd_config));
		cfg = rspamd_config_new ();

		cfg->rcl_obj = obj;
		cfg->cache = rspamd_symbols_cache_new (cfg);
		top = rspamd_rcl_config_init (cfg);

		if (!rspamd_rcl_parse (top, cfg, cfg->cfg_pool, cfg->rcl_obj, &err)) {
			msg_err_config ("rcl parse error: %s", err->message);
			ucl_object_unref (obj);
			lua_pushnil (L);
		}
		else {
			rspamd_config_post_load (cfg, FALSE);
			pcfg = lua_newuserdata (L, sizeof (struct rspamd_config *));
			rspamd_lua_setclass (L, "rspamd{config}", -1);
			*pcfg = cfg;
		}
	}

	return 1;
}

static gboolean
lua_util_task_fin (struct rspamd_task *task, void *ud)
{
	ucl_object_t **target = ud;

	*target = rspamd_protocol_write_ucl (task);
	rdns_resolver_release (task->resolver->r);

	return TRUE;
}

static gint
lua_util_process_message (lua_State *L)
{
	struct rspamd_config *cfg = lua_check_config (L, 1);
	const gchar *message;
	gsize mlen;
	struct rspamd_task *task;
	struct event_base *base;
	ucl_object_t *res = NULL;

	message = luaL_checklstring (L, 2, &mlen);

	if (cfg != NULL && message != NULL) {
		base = event_init ();
		rspamd_init_filters (cfg, FALSE);
		task = rspamd_task_new (NULL, cfg);
		task->ev_base = base;
		task->msg.begin = rspamd_mempool_alloc (task->task_pool, mlen);
		rspamd_strlcpy ((gpointer)task->msg.begin, message, mlen);
		task->msg.len = mlen;
		task->fin_callback = lua_util_task_fin;
		task->fin_arg = &res;
		task->resolver = dns_resolver_init (NULL, base, cfg);
		task->s = rspamd_session_create (task->task_pool, rspamd_task_fin,
					rspamd_task_restore, (event_finalizer_t)rspamd_task_free, task);

		if (!rspamd_task_load_message (task, NULL, message, mlen)) {
			lua_pushnil (L);
		}
		else {
			if (rspamd_task_process (task, RSPAMD_TASK_PROCESS_ALL)) {
				event_base_loop (base, 0);

				if (res != NULL) {
					ucl_object_push_lua (L, res, true);

					ucl_object_unref (res);
				}
				else {
					ucl_object_push_lua (L, rspamd_protocol_write_ucl (task),
							true);
					rdns_resolver_release (task->resolver->r);
					rspamd_session_destroy (task->s);
				}
			}
			else {
				lua_pushnil (L);
			}
		}

		event_base_free (base);
	}
	else {
		lua_pushnil (L);
	}

	return 1;
}

static gint
lua_util_encode_base64 (lua_State *L)
{
	struct rspamd_lua_text *t;
	const gchar *s = NULL;
	gchar *out;
	gsize inlen, outlen;
	guint str_lim = 0;

	if (lua_type (L, 1) == LUA_TSTRING) {
		s = luaL_checklstring (L, 1, &inlen);
	}
	else if (lua_type (L, 1) == LUA_TUSERDATA) {
		t = lua_check_text (L, 1);

		if (t != NULL) {
			s = t->start;
			inlen = t->len;
		}
	}

	if (lua_gettop (L) > 1) {
		str_lim = luaL_checknumber (L, 2);
	}

	if (s == NULL) {
		lua_pushnil (L);
	}
	else {
		out = rspamd_encode_base64 (s, inlen, str_lim, &outlen);

		if (out != NULL) {
			t = lua_newuserdata (L, sizeof (*t));
			rspamd_lua_setclass (L, "rspamd{text}", -1);
			t->start = out;
			t->len = outlen;
			/* Need destruction */
			t->own = TRUE;
		}
		else {
			lua_pushnil (L);
		}
	}

	return 1;
}

static gint
lua_util_decode_base64 (lua_State *L)
{
	struct rspamd_lua_text *t;
	const gchar *s = NULL;
	gsize inlen, outlen;
	gboolean zero_copy = FALSE, grab_own = FALSE;
	gint state = 0;
	guint save = 0;

	if (lua_type (L, 1) == LUA_TSTRING) {
		s = luaL_checklstring (L, 1, &inlen);
	}
	else if (lua_type (L, 1) == LUA_TUSERDATA) {
		t = lua_check_text (L, 1);

		if (t != NULL) {
			s = t->start;
			inlen = t->len;
			zero_copy = TRUE;
			if (t->own) {
				t->own = FALSE;
				grab_own = TRUE;
			}
		}
	}

	if (s != NULL) {
		if (zero_copy) {
			/* Decode in place */
			outlen = g_base64_decode_step (s, inlen, (guchar *)s, &state, &save);
			t = lua_newuserdata (L, sizeof (*t));
			rspamd_lua_setclass (L, "rspamd{text}", -1);
			t->start = s;
			t->len = outlen;
			t->own = grab_own;
		}
		else {
			t = lua_newuserdata (L, sizeof (*t));
			rspamd_lua_setclass (L, "rspamd{text}", -1);
			t->len = (inlen / 4) * 3 + 3;
			t->start = g_malloc (t->len);
			outlen = g_base64_decode_step (s, inlen, (guchar *)t->start,
					&state, &save);
			t->len = outlen;
			t->own = TRUE;
		}
	}
	else {
		lua_pushnil (L);
	}

	return 1;
}

static gint
lua_util_tokenize_text (lua_State *L)
{
	const gchar *in = NULL;
	gsize len, pos, ex_len, i;
	GList *exceptions = NULL, *cur;
	struct rspamd_lua_text *t;
	struct process_exception *ex;
	GArray *res;
	rspamd_ftok_t *w;
	gboolean compat = FALSE;

	if (lua_type (L, 1) == LUA_TSTRING) {
		in = luaL_checklstring (L, 1, &len);
	}
	else if (lua_type (L, 1) == LUA_TTABLE) {
		t = lua_check_text (L, 1);

		if (t) {
			in = t->start;
			len = t->len;
		}
	}

	if (in == NULL) {
		lua_pushnil (L);
		return 1;
	}

	if (lua_gettop (L) > 1 && lua_type (L, 2) == LUA_TTABLE) {
		lua_pushvalue (L, 2);
		lua_pushnil (L);

		while (lua_next (L, -2) != 0) {
			if (lua_type (L, -1) == LUA_TTABLE) {
				lua_rawgeti (L, -1, 1);
				pos = luaL_checknumber (L, -1);
				lua_pop (L, 1);
				lua_rawgeti (L, -1, 2);
				ex_len = luaL_checknumber (L, -1);
				lua_pop (L, 1);

				if (ex_len > 0) {
					ex = g_slice_alloc (sizeof (*ex));
					ex->pos = pos;
					ex->len = ex_len;
					exceptions = g_list_prepend (exceptions, ex);
				}
			}
			lua_pop (L, 1);
		}

		lua_pop (L, 1);
	}

	if (lua_gettop (L) > 2 && lua_type (L, 3) == LUA_TBOOLEAN) {
		compat = lua_toboolean (L, 3);
	}

	if (exceptions) {
		exceptions = g_list_reverse (exceptions);
	}

	res = rspamd_tokenize_text ((gchar *)in, len, TRUE, NULL, exceptions, compat,
			NULL);

	if (res == NULL) {
		lua_pushnil (L);
	}
	else {
		lua_newtable (L);

		for (i = 0; i < res->len; i ++) {
			w = &g_array_index (res, rspamd_ftok_t, i);
			lua_pushlstring (L, w->begin, w->len);
			lua_rawseti (L, -2, i + 1);
		}
	}

	cur = exceptions;
	while (cur) {
		ex = cur->data;
		g_slice_free1 (sizeof (*ex), ex);
		cur = g_list_next (cur);
	}

	g_list_free (exceptions);

	return 1;
}

static gint
lua_util_tanh (lua_State *L)
{
	gdouble in = luaL_checknumber (L, 1);

	lua_pushnumber (L, tanh (in));

	return 1;
}

static gint
lua_util_parse_html (lua_State *L)
{
	struct rspamd_lua_text *t;
	const gchar *start = NULL;
	gsize len;
	GByteArray *res, *in;
	rspamd_mempool_t *pool;
	struct html_content *hc;

	if (lua_type (L, 1) == LUA_TUSERDATA) {
		t = lua_check_text (L, 1);

		if (t != NULL) {
			start = t->start;
			len = t->len;
		}
	}
	else if (lua_type (L, 1) == LUA_TSTRING) {
		start = luaL_checklstring (L, 1, &len);
	}

	if (start != NULL) {
		pool = rspamd_mempool_new (rspamd_mempool_suggest_size (), NULL);
		hc = rspamd_mempool_alloc0 (pool, sizeof (*hc));
		in = g_byte_array_sized_new (len);
		g_byte_array_append (in, start, len);

		res = rspamd_html_process_part (pool, hc, in);

		t = lua_newuserdata (L, sizeof (*t));
		rspamd_lua_setclass (L, "rspamd{text}", -1);
		t->start = res->data;
		t->len = res->len;
		t->own = TRUE;

		g_byte_array_free (res, FALSE);
		g_byte_array_free (in, TRUE);
		rspamd_mempool_delete (pool);
	}
	else {
		lua_pushnil (L);
	}

	return 1;
}

static gint
lua_util_levenshtein_distance (lua_State *L)
{
	const gchar *s1, *s2;
	gsize s1len, s2len;
	gint dist = 0;

	s1 = luaL_checklstring (L, 1, &s1len);
	s2 = luaL_checklstring (L, 2, &s2len);

	if (s1 && s2) {
		dist = rspamd_strings_levenshtein_distance (s1, s1len, s2, s2len);
	}

	lua_pushnumber (L, dist);

	return 1;
}

static gint
lua_util_parse_addr (lua_State *L)
{
	InternetAddressList *ia;
	InternetAddress *addr;
	const gchar *str = luaL_checkstring (L, 1);
	int i, cnt;

	if (str) {
		ia = internet_address_list_parse_string (str);

		if (ia == NULL) {
			lua_pushnil (L);
		}
		else {
			cnt = internet_address_list_length (ia);
			lua_newtable (L);

			for (i = 0; i < cnt; i ++) {
				addr = internet_address_list_get_address (ia, i);

				lua_newtable (L);
				lua_pushstring (L, "name");
				lua_pushstring (L, internet_address_get_name (addr));
				lua_settable (L, -3);

				if (INTERNET_ADDRESS_IS_MAILBOX (addr)) {
					lua_pushstring (L, "addr");
					lua_pushstring (L, internet_address_mailbox_get_addr (
							INTERNET_ADDRESS_MAILBOX (addr)));
					lua_settable (L, -3);
				}

				lua_rawseti (L, -2, (i + 1));
			}

			g_object_unref (ia);
		}
	}
	else {
		lua_pushnil (L);
	}

	return 1;
}

static gint
lua_util_fold_header (lua_State *L)
{
	const gchar *name, *value;
	GString *folded;

	name = luaL_checkstring (L, 1);
	value = luaL_checkstring (L, 2);

	if (name && value) {
		folded = rspamd_header_value_fold (name, value, 0);

		if (folded) {
			lua_pushlstring (L, folded->str, folded->len);
			g_string_free (folded, TRUE);

			return 1;
		}
	}

	lua_pushnil (L);
	return 1;
}

static gint
lua_util_is_uppercase (lua_State *L)
{
	const gchar *str, *p;
	gsize sz, remain;
	gunichar uc;
	guint nlc = 0, nuc = 0;

	str = luaL_checklstring (L, 1, &sz);
	remain = sz;

	if (str && remain > 0) {
		while (remain > 0) {
			uc = g_utf8_get_char_validated (str, remain);
			p = g_utf8_next_char (str);

			if (p - str > (gint) remain) {
				break;
			}

			remain -= p - str;

			if (g_unichar_isupper (uc)) {
				nuc++;
			}
			else if (g_unichar_islower (uc)) {
				nlc++;
			}

			str = p;
		}
	}

	if (nuc > 0 && nlc == 0) {
		lua_pushboolean (L, TRUE);
	}
	else {
		lua_pushboolean (L, FALSE);
	}

	return 1;
}

static gint
lua_util_humanize_number (lua_State *L)
{
	gdouble number = luaL_checknumber (L, 1);
	gchar numbuf[32];


	rspamd_snprintf (numbuf, sizeof (numbuf), "%hL", (gint64)number);
	lua_pushstring (L, numbuf);

	return 1;
}

static gint
lua_util_get_tld (lua_State *L)
{
	const gchar *host;
	gsize hostlen;
	rspamd_ftok_t tld;

	host = luaL_checklstring (L, 1, &hostlen);

	if (host) {
		if (!rspamd_url_find_tld (host, hostlen, &tld)) {
			lua_pushlstring (L, host, hostlen);
		}
		else {
			lua_pushlstring (L, tld.begin, tld.len);
		}
	}
	else {
		lua_pushnil (L);
	}

	return 1;
}


static gint
lua_util_glob (lua_State *L)
{
	const gchar *pattern;
	glob_t gl;
	gint top, i, flags;

	top = lua_gettop (L);
	memset (&gl, 0, sizeof (gl));
	flags = GLOB_NOSORT;

	for (i = 1; i <= top; i ++, flags |= GLOB_APPEND) {
		pattern = luaL_checkstring (L, i);

		if (pattern) {
			glob (pattern, flags, NULL, &gl);
		}
	}

	lua_newtable (L);
	/* Push results */
	for (i = 0; i < (gint)gl.gl_pathc; i ++) {
		lua_pushstring (L, gl.gl_pathv[i]);
		lua_rawseti (L, -2, i + 1);
	}

	globfree (&gl);

	return 1;
}

static gint
lua_util_parse_mail_address (lua_State *L)
{
	InternetAddressList *ia;
	const gchar *str = luaL_checkstring (L, 1);
	gboolean ret = FALSE;

	if (str) {
		ia = internet_address_list_parse_string (str);

		if (ia != NULL) {
			ret = TRUE;

			lua_push_internet_address_list (L, ia);
#ifdef GMIME24
		g_object_unref (ia);
#else
		internet_address_list_destroy (ia);
#endif
		}
	}

	if (!ret) {
		lua_pushnil (L);
	}

	return 1;
}

static gint
lua_load_util (lua_State * L)
{
	lua_newtable (L);
	luaL_register (L, NULL, utillib_f);

	return 1;
}

void
luaopen_util (lua_State * L)
{
	rspamd_lua_add_preload (L, "rspamd_util", lua_load_util);
}