RSI based Envelope Style Trading Indicator - Amibroker AFL Code

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// RSI Levels - appplied to Price Chart shows how far 
// tomorrow's closing price has to move in order for 
// the RSI to cross the 70, 50 & 30 levels. 

pd = Param("Periods",13,5,144,1); 
pds = 2*pd-1;//     (Adjustment for Wilders MA) 
aa = Close-Ref(Close,-1); 
uu = EMA(Max(0,aa),pds); 
dd=  EMA((Max(0,0-aa)),pds); 

rf = IIf(C>2,1000,10000); 

c1 = Param("Upper Level",70,50,90,1); 
qq1 =100/(100-c1)-1; 
ff1 = qq1*dd-uu; 
ff2 = ff1/qq1; 
f1 = Max(ff1,ff2); 
UL = Close + f1*(pds-1)/2; 
UL = IIf(UL>C,floor(UL*rf),ceil(UL*rf))/rf; 

c2 = Param("Equilibrium",50,50,50,0); 
qq2 =100/(100-c2)-1;// [=1] 
ff = dd-uu; 
MM = Close + ff*(pds-1)/2; 
MM = IIf(MM>C,floor(MM*rf),ceil(MM*rf))/rf; 

c3 = Param("Lower Level",30,10,50,1); 
qq3 =100/(100-c3)-1; 
ff1 = qq3*dd-uu; 
ff2 = ff1/qq3; 
f3 = Min(ff1,ff2); 
LL = Close + f3*(pds-1)/2; 
LL = IIf(LL>C,floor(LL*rf),ceil(LL*rf))/rf; 

Plot(UL,"",29,1); 
Plot(MM,"",29,32); 
Plot(LL,"",29,1); 

Cbr = IIf(UL<C,27,IIf(LL>C,32,IIf(MM>C,11,8))); 
PlotOHLC(O,H,L,C,"",cbr,styleCandle); 

X=Cross( C,LL);
Y=Cross(UL,C);

Buy= X ;
Sell= Y ;

PlotShapes(shapeUpArrow*Buy,colorLime,0,L,-15);
PlotShapes(shapeDownArrow*Sell,colorRed,0,H,-15);

Filter=Buy OR Sell ;
AddTextColumn(FullName(),"Name");
AddColumn(Buy,"Buy");
AddColumn(Sell,"sell");


Title = Name() + "  -  RSI(" + WriteVal(pd,0.0) + ")  -  Close=" +  WriteVal(Close,0.3) + "    UL=" +  WriteVal(UL,0.4) + "    MM=" +  WriteVal(MM,0.4) + "    LL=" +  WriteVal(LL,0.4);