{
    new szString[128];
    if ( isnull ( params ) )
    {
        SendClientMessage( playerid, -1, "Format:{FF9900} /duel (invite, accept, decline, block)");
    }
    if ( strcmp ( params, "invite", true ) == 0 )
    {
        new iVictim, iTrack;
        if ( sscanf ( params, "ii", iVictim, iTrack ) ) return SendClientMessage( playerid, -1, "Format:{FF9900} /duel invite [playerid] [track] "),
            SendClientMessage( playerid, -1, "Tracks:{FF9900} [Stadium: 1] [Star Tower: 2] [Trailer Park: 3] " );

        else
        {
            if ( iVictim == playerid )
            {
                return SendClientMessage( playerid, COLOR_LIGHTRED, "ERROR: You can't challenge yourself." );
            }
            if ( IsPlayerNPC ( iVictim ) )
            {
                return SendClientMessage ( playerid, -1, " You cannot do this to NPC's!" );
            }
            if ( BlockingDuels[iVictim] == 1)
            {
                return SendClientMessage( playerid, COLOR_LIGHTRED, "ERROR: This person is blocking duels. ");
            }
            if ( iTrack < 0 || iTrack > 3 )
            {
                return SendClientMessage( playerid, -1, "Tracks:{FF9900} [Stadium: 1] [Star Tower: 2] [Trailer Park: 3] " );
            }

            if ( !IsPlayerConnected( iVictim ) )
            {
                return SendClientMessage( playerid, COLOR_LIGHTRED, "ERROR: Player is not connected. " );
            }

            if ( iVictim == playerid )
            {
                return SendClientMessage( playerid, COLOR_LIGHTRED, "ERROR: You can't have a duel with yourself.");
            }

            Invited[playerid] = iVictim;
            InvitedBy[iVictim] = playerid;
            Track[playerid] = iTrack;

            new szTrack[32];
            switch ( iTrack )
            {
                case 0: szTrack = "Stadium";
                case 1: szTrack = "Star Tower";
                case 2: szTrack = "Trailer Park";
            }

            format( szString, 128, "DUEL: %s is challenging you to a duel [Track: %s]. Type /duel decline or /duel accept.", GetName( playerid ), szTrack );
            SendClientMessage( iVictim, COLOR_LIGHTBLUE, szString );
        }
    }
    else if ( strcmp ( params, "accept", true ) == 0 )
    {
        if ( InvitedBy[playerid] == -1 )
        {
            SendClientMessage( playerid, COLOR_LIGHTRED, "ERROR: Nobody invited you to a duel yet.");
        }
        else
        {
            foreach(Player, i)
            {
                if ( Invited[i] == playerid )
                {
                    if ( InvitedBy[playerid] == i )
                    {
                        format( szString, 128, "INFO: You've accepted %s's invitation for a duel.", GetName( i ) );
                        SendClientMessage( playerid, COLOR_LIGHTBLUE, szString );
                        format( szString, 128, "INFO: %s has accepted your duel invitation", GetName( playerid ) );
                        SendClientMessage( i, COLOR_LIGHTBLUE, szString );

                        switch ( Track[i] )
                        {
                            case 0:
                            {
                                SetPlayerPos( i, 1346.5876,2183.4434,11.0234 );
                                SetPlayerPos( playerid, 1379.2778,2155.8127,11.0234 );
                            }
                            case 1:
                            {
                                SetPlayerPos( i, 1557.2540,-1346.5852,329.4609 );
                                SetPlayerPos( playerid, 1529.0140,-1358.4303,329.4609 );
                            }
                            case 2:
                            {
                                SetPlayerPos( i, -19.9413,1379.3442,9.1719 );
                                SetPlayerPos( playerid, 0.4619,1361.3961,9.1719 );
                            }
                        }

                        new rVW = random( 1 + 1023 );
                        GivePlayerWeapon( i, 24, 100 );
                        GivePlayerWeapon( playerid, 24, 100 );
                        SetPlayerVirtualWorld( i, rVW );
                        SetPlayerVirtualWorld( playerid, rVW );

                        Invited[i] = -1;
                        InvitedBy[i] = -1;
                        Track[i] -= 1;

                        Invited[playerid] = -1;
                        InvitedBy[playerid] = -1;
                        Track[playerid] -= 1;

                        format( szString, 128, "DUEL: The duel between %s and %s has started! ", GetName( i ), GetName( playerid ) );
                        SendClientMessageToAll( COLOR_ORANGE, szString );
                    }
                    else return SendClientMessage( playerid, COLOR_LIGHTRED, "ERROR: You were not invited by this person.");
                }
                else return SendClientMessage( playerid, COLOR_LIGHTRED, "ERROR: You were not invited by this person.");
            }
        }
    }
    else if ( strcmp ( params, "decline", true ) == 0 )
    {
        if ( InvitedBy[playerid] == -1 )
        {
            SendClientMessage( playerid, COLOR_LIGHTRED, "ERROR: Nobody invited you to a duel yet.");
        }
        else
        {
            foreach(Player, i)
            {
                if ( Invited[i] == playerid )
                {
                    if ( InvitedBy[playerid] == i )
                    {
                        format( szString, 128, "INFO: You've declined %s's invitation for a duel.", GetName( i ) );
                        SendClientMessage( playerid, COLOR_LIGHTBLUE, szString );
                        format( szString, 128, "INFO: %s has declined your duel invitation", GetName( playerid ) );
                        SendClientMessage( i, COLOR_LIGHTBLUE, szString );

                        Invited[i] = -1;
                        InvitedBy[i] = -1;
                        Track[i] -= 1;

                        Invited[playerid] = -1;
                        InvitedBy[playerid] = -1;
                        Track[playerid] -= 1;
                    }
                    else return SendClientMessage( playerid, COLOR_LIGHTRED, "ERROR: You were not invited by this person.");
                }
                else return SendClientMessage( playerid, COLOR_LIGHTRED, "ERROR: You were not invited by this person.");
            }
        }
    }
    else if ( strcmp ( params, "block", true ) == 0 )
    {
        if ( BlockingDuels[ playerid ] == 1 )
        {
            BlockingDuels[ playerid ] = 0;
            SendClientMessage( playerid, -1, "{c0c0c0}You are now allowing duel invitations.");
        }
        else if ( BlockingDuels[ playerid ] == 0 )
        {
            BlockingDuels[ playerid ] = 1;
            SendClientMessage( playerid, -1, "{c0c0c0}You are now disallowing duel invitations.");
        }
    }
    return 1;
}