/*
  MS Darvas Box with Exploration
  ==============================

  
  Translate from http://trader.online.pl/MSZ/e-w-Darvis_Box.html
  
  - Improve scripting
      * Allow Darvas Box Color/Style Changing
  - Exploration
      * Scan Price From .. To
*/
SetChartOptions( 0, chartShowArrows|chartShowDates ); 

_SECTION_BEGIN("Price Chart");

_N(Title = StrFormat("{{NAME}}- {{INTERVAL}} {{DATE}} O= %g, H= %g, L= %g, C= %g (%.1f%%) V= " +WriteVal( V, 1.0 ) +"\n{{VALUES}}", O, H, L, C, SelectedValue( ROC( C, 1 )) ));
PriceStyle = GetPriceStyle();
PriceStyleOpt = ParamStyle("Price Style")|PriceStyle;

if (PriceStyle==styleCandle)
   Plot( C, "", colorBlack,  PriceStyleOpt); 
else
   Plot( C, "", IIf( Close >= Ref(C, -1), colorBlue, colorRed ), PriceStyleOpt);

_SECTION_END();

_SECTION_BEGIN("Darvas Box");

Periods= Param("Darvas Periods",5,5,260); 

boxHigh = Ref(H,-3)>=Ref(HHV(H,Periods),-4) AND 
                  Ref(H,-3)>Ref(H,-2) AND Ref(H,-3)>Ref(H,-1) AND Ref(H,-3)>H;

Topbox=ValueWhen(boxHigh, Ref(H,-3)); 
Botbox=ValueWhen(boxHigh,LLV(L,4)); 
 

/*=========================
  - Allow color change
  - Style change 
 ==========================*/
Plot(TopBox, "Top", ParamColor("Box Top Color",  colorRed),    ParamStyle("Box Top Style"));
Plot(Botbox, "Bot", ParamColor("Box Bottom Color",colorBlue),  ParamStyle("Box Bottom Style"));

_SECTION_END();

_SECTION_BEGIN("Exploration");

//== Price Increment Value - depend on different country
Inc = 0.1;  


//== Set the Price Range for stock to scan
PriceFrom = Param("Price From:", 5,   0.1, 200, Inc); 
PriceTo   = Param("Price To:",   100, 0.1, 200, Inc); 

/*
   MAV - Moving Average of Volume
    Buy  - Default 20 days  
    Sell - default 10 days

  Filter:
   Buy:  Today Buy Volume must be > N time of Buy MAV. 
         (Buy Up required Huge push force)
         The previous Day High must be below the Darvas Top and Today must close above Darvas Top 

   Sell: Today Sell Volume must be > N time of Sell MAV
         (Sell Down required small pull force)
         The previous Day Low must be above the Darvas bottom and Today must close below Darvas Low 

*/
Buy_MAPds  = Param("Buy: MAV. Periods",  20, 1, 260); 
Buy_VxMAV  = Param("Buy: V > NxMAV",  2, 0, 20, 0.1); 
Sell_MAPds = Param("Sell: MAV. Periods",  10, 1, 260); 
Sell_VxMAV = Param("Sell: V > NxMAV",  1, 0, 20, 0.1); 

BuyMAV = MA(V, Buy_MAPds);
SellMAV = MA(V, Sell_MAPds);

/* Rule to Filter
   - 
   - The previous Day High must be inside the Darvas Top and Today must close above Darvas Top 

*/
Buy = Ref(H, -1) <=TopBox AND C>TopBox  AND (V>Buy_VxMAV*BuyMAV); 
Sell = Ref(L, -1) >=Botbox AND C<Botbox AND (V>Sell_VxMAV*SellMAV); 


Filter  = (Buy OR Sell) AND (C>=PriceFrom AND C<=PriceTo);

AddTextColumn(FullName(), "Security", 1.0, colorDefault, colorDefault, 200); 
AddTextColumn(WriteIf(Buy, "Buy", WriteIf(Sell, "Sell", "-")), "Trade", 1.0, 
                      colorYellow,
                      IIf(Buy, colorGreen, IIf(Sell, colorRed, colorDefault)),  50);
AddColumn(C, "Price", 0.3, colorDefault, colorDefault, 60); 
AddColumn(V, "Volume", 1.0, colorDefault, colorDefault,80); 

_SECTION_END();