Welles Wilder Volatility Stop

{ Wilder Volatility Stop Trail }
[Target=price]
Mult:=Input("ATR Multiplier",3,1);
Nb:=if(Mult<3,7,Int(Mult*2+1));
Long :=Ref(HHV(C,Nb),-1) - (Ref(ATR(Nb),-1)*Mult);
Short:=Ref(LLV(C,Nb),-1) + (Ref(ATR(Nb),-1)*Mult);
trail:=
If(C>PREV and Ref(C,-1)>PREV, Max(PREV,Long),
If(C<PREV and Ref(C,-1)<PREV, Min(PREV,Short),
If(C>PREV, Long, Short)));
Trail;
[linestyle=pricecolor]
[color=rgb(0,174,0)] if(C>=Trail,1,0);
[color=rgb(255,85,85)] if(C<Trail,1,0);