/*

 *

 * (C) 2018-26 - ntop.org

 *

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 3 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software Foundation,

 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

 *

 */

#include "ntop_includes.h"

/* ******************************************************* */

TimeseriesExporter::TimeseriesExporter(NetworkInterface* _if) {

  if (trace_new_delete)

    ntop->getTrace()->traceEvent(TRACE_NORMAL, "[new] %s", __FILE__);

  iface = _if;

}

/* ******************************************************* */

TimeseriesExporter::~TimeseriesExporter() {}

/* ******************************************************* */

bool TimeseriesExporter::is_table_empty(lua_State* L, int index) {

  lua_pushnil(L);

  if (lua_next(L, index)) {

    lua_pop(L, 1);

    return (false);

  }

  return (true);

}

/* ******************************************************* */

/* NOTE: outbuf and unescaped buffers must not overlap.

   Need to escape spaces at least.

   See

   https://docs.influxdata.com/influxdb/v1.7/write_protocols/line_protocol_tutorial/#special-characters

*/

int TimeseriesExporter::escape_spaces(char* buf, int buf_len,

                                      const char* unescaped) {

  int cur_len = 0;

  while (*unescaped) {

    if (cur_len >= buf_len - 2) goto influx_escape_char_err;

    switch (*unescaped) {

      case ' ':

        *buf++ = '\\';

        cur_len++;

        /* No break */

      default:

        *buf++ = *unescaped++;

        cur_len++;

        break;

    }

  }

  *buf = '\0';

  return cur_len;

influx_escape_char_err:

  *(buf - cur_len) = '\0';

  return -1;

}

/* ******************************************************* */

int TimeseriesExporter::line_protocol_concat_table_fields(

    lua_State* L, int index, char* buf, int buf_len,

    int (*escape_fn)(char* outbuf, int outlen, const char* orig)) {

  bool first = true;

  char val_buf[128];

  int cur_buf_len = 0, n;

  bool write_ok;

  // table traversal from https://www.lua.org/ftp/refman-5.0.pdf

  lua_pushnil(L);

  while (lua_next(L, index) != 0) {

    const char* s = lua_tostring(L, -1);

    write_ok = false;

    if (escape_fn)

      n = escape_fn(val_buf, sizeof(val_buf), s);

    else

      n = snprintf(val_buf, sizeof(val_buf), "%s", s);

    if (n > 0 && n < (int)sizeof(val_buf)) {

      n = snprintf(buf + cur_buf_len, buf_len - cur_buf_len, "%s%s=%s",

                   first ? "" : ",", lua_tostring(L, -2), val_buf);

      if (n > 0 && n < buf_len - cur_buf_len) {

        write_ok = true;

        cur_buf_len += n;

        if (first) first = false;

      }

    }

    lua_pop(L, 1);

    if (!write_ok) goto line_protocol_concat_table_fields_err;

  }

  return cur_buf_len;

line_protocol_concat_table_fields_err:

  if (buf_len) buf[0] = '\0';

  return -1;

}

/* ******************************************************* */

int TimeseriesExporter::line_protocol_write_line(

    lua_State* vm, char* dst_line, int dst_line_len,

    int (*escape_fn)(char* outbuf, int outlen, const char* orig)) {

  char* schema;

  time_t tstamp;

  int cur_line_len = 0, n;

  if (ntop_lua_check(vm, __FUNCTION__, 1, LUA_TSTRING) != CONST_LUA_OK)

    return -1;

  schema = (char*)lua_tostring(vm, 1);

  if (ntop_lua_check(vm, __FUNCTION__, 2, LUA_TNUMBER) != CONST_LUA_OK)

    return -1;

  tstamp = (time_t)lua_tonumber(vm, 2);

  if (ntop_lua_check(vm, __FUNCTION__, 3, LUA_TTABLE) != CONST_LUA_OK)

    return -1;

  if (ntop_lua_check(vm, __FUNCTION__, 4, LUA_TTABLE) != CONST_LUA_OK)

    return -1;

  /* A line of the protocol is: "iface:traffic,ifid=0 bytes=0 1539358699\n" */

  /* measurement name (with a comma if no tags are found) */

  n = snprintf(dst_line, dst_line_len, is_table_empty(vm, 3) ? "%s" : "%s,",

               schema);

  if (n < 0 || n >= dst_line_len)

    goto line_protocol_write_line_err;

  else

    cur_line_len += n;

  /* tags */

  n = line_protocol_concat_table_fields(vm, 3, dst_line + cur_line_len,

                                        dst_line_len - cur_line_len,

                                        escape_fn);  // tags

  if (n < 0 || n >= dst_line_len - cur_line_len)

    goto line_protocol_write_line_err;

  else

    cur_line_len += n;

  /* space to separate tags and metrics */

  n = snprintf(dst_line + cur_line_len, dst_line_len - cur_line_len, " ");

  if (n < 0 || n >= dst_line_len - cur_line_len)

    goto line_protocol_write_line_err;

  else

    cur_line_len += n;

  /* metrics */

  n = line_protocol_concat_table_fields(vm, 4, dst_line + cur_line_len,

                                        dst_line_len - cur_line_len,

                                        escape_fn);  // metrics

  if (n < 0 || n >= dst_line_len - cur_line_len)

    goto line_protocol_write_line_err;

  else

    cur_line_len += n;

  /* timestamp (in seconds, not nanoseconds) and a \n */

  n = snprintf(dst_line + cur_line_len, dst_line_len - cur_line_len, " %lu\n",

               tstamp);

  if (n < 0 || n >= dst_line_len - cur_line_len)

    goto line_protocol_write_line_err;

  else

    cur_line_len += n;

  return cur_line_len;

line_protocol_write_line_err:

  if (dst_line_len) dst_line[0] = '\0';

  return -1;

}