Bollinger Band Trend for Amibroker (AFL)

_SECTION_BEGIN("Bollinger Band Trend Filter");

ST_TR=EMA(C,5);
MID_TR=EMA(C,10);
INT_TR=EMA(C,15);
LNG_TR=EMA(C,20);

ST_VAL = IIf(ST_TR > BBandTop(C,15,0.5),1, IIf(ST_TR<BBandTop(C,15,0.5) AND ST_TR>BBandBot(C,15,0.5),0,-1));
MID_VAL = IIf(MID_TR > BBandTop(C,20,0.5),1, IIf(MID_TR<BBandTop(C,20,0.5) AND MID_TR>BBandBot(C,20,0.5),0,-1));
Int_VAL = IIf(INT_TR > BBandTop(C,30,0.5),1, IIf(INT_TR<BBandTop(C,30,0.5) AND INT_TR>BBandBot(C,30,0.5),0,-1));
LNG_VAL = IIf(LNG_TR > BBandTop(C,50,0.5),1, IIf(LNG_TR<BBandTop(C,50,0.5) AND LNG_TR>BBandBot(C,50,0.5),0,-1));

ST_TF = ST_VAL*10;
MID_TF = MID_VAL*20;
INT_TF = Int_VAL*30;
LNG_TF = LNG_VAL*40;


TF= ST_TF + MID_TF + INT_TF + LNG_TF;

// TREND FILTER RANKING
TFRNK = 
IIf(TF>= 50,3,
IIf(TF<50 AND TF>25,2,
IIf(TF<25 AND TF>=0,1,
IIf(TF<0 AND TF>= -25,-1,
IIf(TF<-25 AND TF>=-50,-2,
IIf(TF<-50,-3,0))))));

TFCLR = 
IIf(TFRNK==3,ColorRGB(0,255,0),
IIf(TFRNK==2,colorGreen,
IIf(TFRNK==1,colorOrange,
IIf(TFRNK==-1,ColorRGB(252,70,0),
IIf(TFRNK==-2,ColorRGB(255,80,80),
IIf(TFRNK==-3,ColorRGB(217,0,0),colorGrey40))))));

// PRICE PLOT

Plot(TFRNK,"BB TREND FILTER",TFCLR ,styleThick);
Plot (0,"",colorGrey50,styleLine);
Plot (-.5,"",colorGrey50,styleDashed);
Plot (0.5,"",colorGrey50,styleDashed);


_SECTION_BEGIN("EMA1");
P = ParamField("Price field",-1);
Periods = Param("Periods", 15, 2, 300, 1, 10 );
Plot( EMA( P, Periods ), _DEFAULT_NAME(), ParamColor( "Color", colorCycle ), ParamStyle("Style") ); 
_SECTION_END();