Good swing indicator for Amibroker (AFL)

_SECTION_BEGIN("Price");
SetChartOptions(0,chartShowArrows|chartShowDates);
_N(Title = StrFormat("{{NAME}} - {{INTERVAL}} {{DATE}} Open %g, Hi %g, Lo %g, Close %g (%.1f%%) {{VALUES}}", O, H, L, C, SelectedValue( ROC( C, 1 ) ) ));
Plot( C, "Close", ParamColor("Color", colorBlack ), styleNoTitle | ParamStyle("Style") | GetPriceStyle() ); 
_SECTION_END();

_SECTION_BEGIN("Background_Setting");
SetChartBkGradientFill( ParamColor("BgTop", colorBlack),

ParamColor("BgBottom", colorBlack),ParamColor("titleblock",colorDarkTeal ));
_SECTION_END();

_SECTION_BEGIN("Time Left");
function GetSecondNum()
{
Time = Now( 4 );
Seconds = int( Time % 100 );
Minutes = int( Time / 100 % 100 );
Hours = int( Time / 10000 % 100 );
SecondNum = int( Hours * 60 * 60 + Minutes * 60 + Seconds );
return SecondNum;
}
RequestTimedRefresh( 1 );
TimeFrame = Interval();
SecNumber = GetSecondNum();
Newperiod = SecNumber % TimeFrame == 0;
SecsLeft = SecNumber - int( SecNumber / TimeFrame ) * TimeFrame;
SecsToGo = TimeFrame - SecsLeft;

x=Param("xposn",300,0,1000,1);
y=Param("yposn",50,0,1000,1);

GfxSelectSolidBrush( ColorRGB( 230, 230, 230 ) );
GfxSelectPen( ColorRGB( 230, 230, 230 ), 2 );
if ( NewPeriod )
{
GfxSelectSolidBrush( colorYellow );
GfxSelectPen( colorYellow, 2 );
Say( "New period" );
}
GfxRoundRect( x+45, y+17, x-3, y-2, 0, 0 );
GfxSetBkMode(1);
GfxSelectFont( "Arial", 12, 700, False );
GfxSetTextColor( colorBlack );
GfxTextOut( ""+SecsToGo+" / "+NumToStr( TimeFrame, 1.0 ), x, y );
_SECTION_END();


_SECTION_BEGIN("swing line");
no=Param( "Swing", 3, 1, 55 );
tsl_col=ParamColor( "Color", colorCycle );

res=HHV(H,no);
sup=LLV(L,no);
avd=IIf(C>Ref(res,-1),1,IIf(C<Ref(sup,-1),-1,0));
avn=ValueWhen(avd!=0,avd,1);
tsl=IIf(avn==1,sup,res);

Plot(tsl, _DEFAULT_NAME(), tsl_col, styleStaircase);

Buy=Cross(C,tsl);
Sell=Cross(tsl,C);

shape=Buy*shapeUpArrow + Sell*shapeDownArrow;
PlotShapes(shape,IIf(Buy,tsl_col,tsl_col),0,IIf(Buy,Low,High));

_SECTION_BEGIN("EMA");
P = ParamField("Price field",-1);
Periods = Param("Periods", 5, 2, 300, 1, 10 );
Plot( EMA( P, Periods ), _DEFAULT_NAME(), ParamColor( "Color", colorCycle ), ParamStyle("Style") ); 
_SECTION_END();