#include <nbase.h>

#include "nse_lua.h"
#include "MACLookup.h"
#include "services.h"
#include "protocols.h"

static inline u8 nibble(char hex) {
  return (hex & 0xf) + ((hex & 0x40) ? 9 : 0);
}

static int l_mac2corp (lua_State *L)
{
  size_t len = 0;
  u8 prefix[6] = {0}; // allow a whole MAC addr.
  size_t i = 0;
  size_t j = 0;
  const char *buf = luaL_checklstring(L, 1, &len);

  if (len == 6) {
    // Option 1: 6-byte raw MAC
    lua_pushstring(L, MACPrefix2Corp((u8 *)buf));
    return 1;
  }

  // Try for hex string.
  for (i = 0; i + 1 < len && j < 6; i+=2 ) {
    if (buf[i] == ':' && i + 2 < len) {
      i++;
    }
    if (isxdigit(buf[i]) && isxdigit(buf[i+1])) {
      prefix[j++] = (nibble(buf[i]) << 4) + nibble(buf[i+1]);
    }
    else {
      break;
    }
  }
  // Require exactly 6 bytes result and used the whole input
  if (j == 6 && i >= len) {
    lua_pushstring(L, MACPrefix2Corp(prefix));
    return 1;
  }
  return luaL_error(L, "Expected a 6-byte MAC address");
}

static int l_getservbyport (lua_State *L)
{
  const struct nservent *serv = NULL;
  static const u16 proto[] = {IPPROTO_TCP, IPPROTO_UDP, IPPROTO_SCTP};
  static const char * op[] = {"tcp", "udp", "sctp"};
  lua_Integer port = luaL_checkinteger(L, 1);
  int i = luaL_checkoption(L, 2, NULL, op);

  if (port < 0 || port > 0xffff) {
    return luaL_error(L, "Port number out of range");
  }

  serv = nmap_getservbyport((u16) port, proto[i]);
  if (serv == NULL) {
    lua_pushnil(L);
  }
  else {
    lua_pushstring(L, serv->s_name);
  }
  return 1;
}

static int l_getprotbynum (lua_State *L)
{
  const struct nprotoent *proto = NULL;
  lua_Integer num = luaL_checkinteger(L, 1);

  if (num < 0 || num > 0xff) {
    return luaL_error(L, "Protocol number out of range");
  }

  proto = nmap_getprotbynum(num);
  if (proto == NULL) {
    lua_pushnil(L);
  }
  else {
    lua_pushstring(L, proto->p_name);
  }
  return 1;
}

static int l_getprotbyname (lua_State *L)
{
  const struct nprotoent *proto = NULL;
  const char *name = luaL_checkstring(L, 1);

  proto = nmap_getprotbyname(name);
  if (proto == NULL) {
    lua_pushnil(L);
  }
  else {
    lua_pushinteger(L, proto->p_proto);
  }
  return 1;
}

LUALIB_API int luaopen_db (lua_State *L)
{
  static const luaL_Reg dblib [] = {
    {"mac2corp", l_mac2corp},
    {"getservbyport", l_getservbyport},
    {"getprotbynum", l_getprotbynum},
    {"getprotbyname", l_getprotbyname},
    {NULL, NULL}
  };
  luaL_newlib(L, dblib);
  return 1;
}