new fight[MAX_PLAYERS]=0;

/////////////////////////////////
if(!strcmp(cmdtext,"/fight",true)
{
    if(fight[playerid] == 0)
    {
        fight[playerid] = 1;
        GivePlayerWeapon..
        SetPlayerPos...
    }
    else if(fight[playerid] == 1)
    {
        fight[playerid] = 0;
        SpawnPlayer(playerid);
    }
    return 1;
}
/////////////////////////////////////////////

if(fight[playerid] == 1)
{
    fight[playerid] = 0;
    OnPlayerCommandText(playerid,"/fight");
}