//+------------------------------------------------------------------+
//|                                               DeMark Channel.mq5 |
//|                             Copyright 2000-2026, MetaQuotes Ltd. |
//|                                                     www.mql5.com |
//+------------------------------------------------------------------+
#property copyright   "2000-2026, MetaQuotes Ltd."
#property link        "https://www.mql5.com"
#property description "DeMark Channel"

#property indicator_chart_window
#property indicator_buffers 3
#property indicator_plots   3
#property indicator_type1   DRAW_LINE
#property indicator_color1  clrGreen
#property indicator_type2   DRAW_LINE
#property indicator_color2  clrBlue
#property indicator_type3   DRAW_LINE
#property indicator_color3  clrRed
//--- labels
#property indicator_label1  "PP"
#property indicator_label2  "R1"
#property indicator_label3  "S1"

//--- input parameter
input bool InpShowLabel=true; // show price of level

//--- indicator buffers
double    ExtPPBuffer[];
double    ExtR1Buffer[];
double    ExtS1Buffer[];

//--- unique prefix for indicator objects
string ExtPrefixUniq;
//--- current chart scale
long   ExtChartScale=2;
//--- price labels should not be shown on the built-in VPS
bool   ExtShowLabel=false;
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int OnInit()
  {
//--- check current timeframe
   if(PeriodSeconds()>PeriodSeconds(PERIOD_D1))
     {
      Alert("Timeframe of chart must be D1 or lower. Exit");
      return(INIT_FAILED);
     }
     
//--- if the indicator is running on the built-in VPS, price labels should not be shown
   if(!TerminalInfoInteger(TERMINAL_VPS))
      ExtShowLabel=InpShowLabel;       

//--- define buffers
   SetIndexBuffer(0, ExtPPBuffer);
   SetIndexBuffer(1, ExtR1Buffer);
   SetIndexBuffer(2, ExtS1Buffer);

//--- indicator name
   IndicatorSetString(INDICATOR_SHORTNAME, "DeMark Channel");
//--- number of digits of indicator value
   IndicatorSetInteger(INDICATOR_DIGITS, _Digits);

//--- prepare prefix for objects
   string number=StringFormat("%I64d", GetTickCount64());
   ExtPrefixUniq=StringSubstr(number, StringLen(number)-4);
   ExtPrefixUniq=ExtPrefixUniq+"_DM";
   Print("Indicator \"DeMark Channels\" started, prefix=", ExtPrefixUniq);

   return(INIT_SUCCEEDED);
  }
//+------------------------------------------------------------------+
//| Custom indicator iteration function                              |
//+------------------------------------------------------------------+
int OnCalculate(const int rates_total,
                const int prev_calculated,
                const datetime &time[],
                const double &open[],
                const double &high[],
                const double &low[],
                const double &close[],
                const long &tick_volume[],
                const long &volume[],
                const int &spread[])
  {
   static MqlRates LAST_DAY[];    // previous day
   static datetime last_time=0;   // reference time
   static datetime error_time=0;  // error output time

//--- if the indicator has previously been calculated, start from the bar preceding the last one
   int start=prev_calculated-1;

//--- if this is the first calculation of the indicator, start from the first bar on the chart
   if(prev_calculated==0)
      start=0;

//--- calculate levels for all bars in a loop
   for(int i=start; i<rates_total; i++)
     {
      //--- get day opening time for the current bar
      datetime rem_seconds=time[i]%PeriodSeconds(PERIOD_D1);
      datetime open_time=time[i]-rem_seconds;

      //--- if the opening time is different from the reference time, update LAST_DAY - level calculations will be based on this value
      if(open_time!=last_time)
        {
         //--- If you're running the indicator on this symbol for the first time,
         //--- first open the D1 chart for the symbol to initiate immediate downloading of daily bars
         //--- if getting the current timeframe bars for the specified day fails
         if(CopyRates(Symbol(), PERIOD_D1, open_time-1, 1, LAST_DAY)!=-1)
           {
            //--- remember the reference time
            last_time=open_time;
           }
         else
           {
            //--- generate error messages no more than once a minute
            if(TimeCurrent()>=error_time)
              {
               error_time=TimeCurrent()+60;
               Print("Failed to get previous day by CopyRates(Symbol(), PERIOD_D1, error ", GetLastError());
              }
            return(prev_calculated);
           }
        }

      //--- preparations
      double day_close=LAST_DAY[0].close;
      double day_open=LAST_DAY[0].open;
      double day_high=LAST_DAY[0].high;
      double day_low=LAST_DAY[0].low;

      //--- initial calculation
      double x=day_high+day_low+2*day_close;
      if(day_close<day_open)
         x=day_high+2*day_low+day_close;
      if(day_close>day_open)
         x=2*day_high+day_low+day_close;

      //--- calculate levels
      double pivot_point=x/4;
      double s1=x/2-day_high;
      double r1=x/2-day_low;

      //--- write values into buffers
      ExtPPBuffer[i]=pivot_point;
      ExtR1Buffer[i]=r1;
      ExtS1Buffer[i]=s1;
     }

//--- draw labels on levels
   if(ExtShowLabel)
     {
      ShowPriceLevels(time[rates_total-1], rates_total-1);
      ChartRedraw();
     }

//--- succesfully calculated
   return(rates_total);
  }
//+------------------------------------------------------------------+
//| Custom indicator deinitialization function                       |
//+------------------------------------------------------------------+
void OnDeinit(const int reason)
  {
//--- delete all our graphical objects after use
   Print("Indicator \"DeMark Channels\" stopped, delete all objects with prefix=", ExtPrefixUniq);
   ObjectsDeleteAll(0, ExtPrefixUniq, 0, OBJ_ARROW_RIGHT_PRICE);
   ChartRedraw(0);
  }
//+------------------------------------------------------------------+
//| Handles CHARTEVENT_CHART_CHANGE to track chart window updates    |
//+------------------------------------------------------------------+
void OnChartEvent(const int id, const long& lparam, const double& dparam, const string& sparam)
  {
   if(id==CHARTEVENT_CHART_CHANGE)
      if(!ChartGetInteger(0, CHART_SCALE, 0, ExtChartScale))
        {
         //--- output an error message to the Experts journal
         Print(__FUNCTION__+", ChartGetInteger(CHART_SCALE) failed, error = ", GetLastError());
        }
//---
  }  
//+------------------------------------------------------------------+
//|  Show prices' levels                                             |
//+------------------------------------------------------------------+
void ShowPriceLevels(datetime time, int last_index)
  {
   ShowRightPrice(ExtPrefixUniq+"_PP", time, ExtPPBuffer[last_index], clrGreen);
   ShowRightPrice(ExtPrefixUniq+"_R1", time, ExtR1Buffer[last_index], clrBlue);
   ShowRightPrice(ExtPrefixUniq+"_S1", time, ExtS1Buffer[last_index], clrRed);
  }
//+------------------------------------------------------------------+
//| Create or Update "Right Price Label" object                      |
//+------------------------------------------------------------------+
bool ShowRightPrice(const string name, datetime time, double price, color clr)
  {
   if(!ObjectCreate(0, name, OBJ_ARROW_RIGHT_PRICE, 0, time, price))
     {
      ObjectMove(0, name, 0, time, price);
      return(false);
     }

//--- adjust label size based on chart scale
   int width=ExtChartScale>1 ? 2:1;  // if chart scale > 1, then label size = 2

   ObjectSetInteger(0, name, OBJPROP_COLOR, clr);
   ObjectSetInteger(0, name, OBJPROP_STYLE, STYLE_SOLID);
   ObjectSetInteger(0, name, OBJPROP_WIDTH, width);
   ObjectSetInteger(0, name, OBJPROP_BACK, false);
   ObjectSetInteger(0, name, OBJPROP_SELECTABLE, false);
   ObjectSetInteger(0, name, OBJPROP_SELECTED, false);
   ObjectSetInteger(0, name, OBJPROP_HIDDEN, true);
   ObjectSetInteger(0, name, OBJPROP_ZORDER, 0);

   return(true);
  }
//+------------------------------------------------------------------+