Elder Auto Envelope

/_SECTION_BEGIN("Elder's AutoEnvelope");
// User inputs
// pds=Input("EMA periods",1,252,21); // MetaStock code ("name",min,max,default)
pds = Param("EMA periods",21,2,252,1);

// pdsBak=Input("lookback periods",1,252,42);
pdsBak=Param("lookback periods",42,2,252,1);

// Price field
WC = TimeFrameGetPrice( "C", inWeekly, -1 ); // gives you previous week Open price

// x=IIf(x=1,O,IIf(x=2,H,IIf(x=3,L,IIf(x=5,WC,C)))); // is this incorrect?
//x=IIf(x==1,O,IIf(x==2,H,IIf(x==3,L,IIf(x==5,WC,C))));
// x=Input("use: Open=1, High=2, Low=3, Close=4, WClose=5",1,5,4);
//x=Param("use: Open=1, High=2, Low=3, Close=4, WClose=5",4,1,5,1);

sX = ParamList("Use Price Field:", "Open|High|Low|Close|Weekly Close", 3);

if (sX == "Open")
      x = O;
else if (sX == "High")
      x = H;
else if (sX == "Low")
      x = L;
else if (sX == "Close")
   x = C;
else if (sX == "Weekly Close")
      x = WC;

// Plot1=Input("[1]AutoEnvelope, [2]Long signals, [3]All signals",1,3,1);
//Plot1=Param("[1]AutoEnvelope, [2]Long signals, [3]All signals",1,1,3,1);

sPlot1 = ParamList("Plot Signals:", "AutoEnvelope|Long signals|All signals", 0);

if (sPlot1 == "AutoEnvelope")
      Plot1 = 1;
else if (sPlot1 == "Long signals")
      Plot1 = 2;
else if (sPlot1 == "All signals")
      Plot1  = 3;

// delay=Input("Entry/Exit signals delay",0,5,0);
delay=Param("Entry/Exit signals delay",0,0,5,1);
 

// Envelope bands
AvgX=EMA(x,pds);
hiAvg=HHV(H,pdsBak);
loAvg=LLV(L,pdsBak);
shift= EMA(IIf(hiAvg > AvgX, hiAvg - AvgX, AvgX - loAvg),pds);
UpperBand=AvgX+shift;
LowerBand=AvgX-shift;

// Envelope signals
In=Cross(x,LowerBand);
Out=Cross(x,UpperBand);
Init=Cum(In + Out > - 1)==1;
InInit=Cum(In)==1;
flag=BarsSince(Init OR In) < BarsSince(Init OR Out)+InInit;
signals=Ref((InInit AND Hold(InInit=0,2) OR flag AND Hold (flag=0,2)) -(flag=0 AND Hold(flag,2)),-delay);

// Plot envelope on price chart
//UpBand = IIf(Plot=1,UpperBand,IIf(Plot1=2,signals,In- Out));
//MidBand = IIf(Plot=1,AvgX,IIf(Plot1=2,0,0));
//LowBand = IIf(Plot=1,LowerBand,IIf(Plot1=2,signals,In- Out));
UpBand = IIf(Plot1==1,UpperBand,IIf(Plot1==2,signals,In- Out));
MidBand = IIf(Plot1==1,AvgX,IIf(Plot1==2,0,0));
LowBand = IIf(Plot1==1,LowerBand,IIf(Plot1==2,signals,In- Out));

if (Plot1 == 1)
      iStyleScale = 0;
else
      iStyleScale = styleOwnScale;
 
Plot(UpBand ,"UpperBand",colorBlueGrey, styleLine | iStyleScale);
Plot(MidBand , "MidleBand", colorGreen, styleLine | iStyleScale);
Plot(LowBand, "LowerBand", colorViolet, styleLine | iStyleScale);
Plot(C, "Price", colorDarkYellow, styleCandle);
_SECTION_END();