//+------------------------------------------------------------------+
//|                                                    Bar level.mq5 |
//|                              Copyright © 2021, Vladimir Karputov |
//|                      https://www.mql5.com/en/users/barabashkakvn |
//+------------------------------------------------------------------+
#property copyright "Copyright © 2021, Vladimir Karputov"
#property link      "https://www.mql5.com/en/users/barabashkakvn"
#property version   "1.000"
#property indicator_chart_window
#property indicator_buffers 0
#property indicator_plots   0
//--- input parameters
//---
double   m_curr_high=DBL_MIN;
double   m_curr_low=DBL_MAX;
datetime m_curr_time=0;
string   m_high_name="Bar Level High";
string   m_low_name="Bar Level Low";
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int OnInit()
  {
//---
   TrendCreate(ChartID(),m_high_name,0,0,0,0,0,clrRed);
   TrendCreate(ChartID(),m_low_name,0,0,0,0,0,clrBlue);
//---
   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[])
  {
//---
   if(prev_calculated==0)
     {
      m_curr_high=high[rates_total-1];
      m_curr_low=low[rates_total-1];
      m_curr_time=time[rates_total-1];
      TrendPointChange(ChartID(),m_high_name,0,time[rates_total-1],m_curr_high);
      TrendPointChange(ChartID(),m_high_name,1,time[rates_total-1]+PeriodSeconds()*3,m_curr_high);
      TrendPointChange(ChartID(),m_low_name,0,time[rates_total-1],m_curr_low);
      TrendPointChange(ChartID(),m_low_name,1,time[rates_total-1]+PeriodSeconds()*3,m_curr_low);
      return(rates_total);
     }
   if(high[rates_total-1]>m_curr_high || low[rates_total-1]<m_curr_low)
     {
      m_curr_high=high[rates_total-1];
      m_curr_low=low[rates_total-1];
      m_curr_time=time[rates_total-1];
      TrendPointChange(ChartID(),m_high_name,0,time[rates_total-1],m_curr_high);
      TrendPointChange(ChartID(),m_high_name,1,time[rates_total-1]+PeriodSeconds()*3,m_curr_high);
      TrendPointChange(ChartID(),m_low_name,0,time[rates_total-1],m_curr_low);
      TrendPointChange(ChartID(),m_low_name,1,time[rates_total-1]+PeriodSeconds()*3,m_curr_low);
      return(rates_total);
     }
   TrendPointChange(ChartID(),m_high_name,0,m_curr_time,m_curr_high);
   TrendPointChange(ChartID(),m_high_name,1,time[rates_total-1]+PeriodSeconds()*3,m_curr_high);
   TrendPointChange(ChartID(),m_low_name,0,m_curr_time,m_curr_low);
   TrendPointChange(ChartID(),m_low_name,1,time[rates_total-1]+PeriodSeconds()*3,m_curr_low);
//--- return value of prev_calculated for next call
   return(rates_total);
  }
//+------------------------------------------------------------------+
//| Indicator deinitialization function                              |
//+------------------------------------------------------------------+
void OnDeinit(const int reason)
  {
   ObjectDelete(ChartID(),m_high_name);
   ObjectDelete(ChartID(),m_low_name);
  }
//+------------------------------------------------------------------+
//| Create a trend line by the given coordinates                     |
//+------------------------------------------------------------------+
bool TrendCreate(const long            chart_ID=0,        // chart's ID
                 const string          name="TrendLine",  // line name
                 const int             sub_window=0,      // subwindow index
                 datetime              time1=0,           // first point time
                 double                price1=0,          // first point price
                 datetime              time2=0,           // second point time
                 double                price2=0,          // second point price
                 const color           clr=clrRed,        // line color
                 const ENUM_LINE_STYLE style=STYLE_SOLID, // line style
                 const int             width=1,           // line width
                 const bool            back=false,        // in the background
                 const bool            selection=false,   // highlight to move
                 const bool            ray_left=false,    // line's continuation to the left
                 const bool            ray_right=true,    // line's continuation to the right
                 const bool            hidden=true,       // hidden in the object list
                 const long            z_order=0)         // priority for mouse click
  {
//--- set anchor points' coordinates if they are not set
   ChangeTrendEmptyPoints(time1,price1,time2,price2);
//--- reset the error value
   ResetLastError();
//--- create a trend line by the given coordinates
   if(!ObjectCreate(chart_ID,name,OBJ_TREND,sub_window,time1,price1,time2,price2))
     {
      Print(__FUNCTION__,
            ": failed to create a trend line! Error code = ",GetLastError());
      return(false);
     }
//--- set line color
   ObjectSetInteger(chart_ID,name,OBJPROP_COLOR,clr);
//--- set line display style
   ObjectSetInteger(chart_ID,name,OBJPROP_STYLE,style);
//--- set line width
   ObjectSetInteger(chart_ID,name,OBJPROP_WIDTH,width);
//--- display in the foreground (false) or background (true)
   ObjectSetInteger(chart_ID,name,OBJPROP_BACK,back);
//--- enable (true) or disable (false) the mode of moving the line by mouse
//--- when creating a graphical object using ObjectCreate function, the object cannot be
//--- highlighted and moved by default. Inside this method, selection parameter
//--- is true by default making it possible to highlight and move the object
   ObjectSetInteger(chart_ID,name,OBJPROP_SELECTABLE,selection);
   ObjectSetInteger(chart_ID,name,OBJPROP_SELECTED,selection);
//--- enable (true) or disable (false) the mode of continuation of the line's display to the left
   ObjectSetInteger(chart_ID,name,OBJPROP_RAY_LEFT,ray_left);
//--- enable (true) or disable (false) the mode of continuation of the line's display to the right
   ObjectSetInteger(chart_ID,name,OBJPROP_RAY_RIGHT,ray_right);
//--- hide (true) or display (false) graphical object name in the object list
   ObjectSetInteger(chart_ID,name,OBJPROP_HIDDEN,hidden);
//--- set the priority for receiving the event of a mouse click in the chart
   ObjectSetInteger(chart_ID,name,OBJPROP_ZORDER,z_order);
//--- successful execution
   return(true);
  }
//+------------------------------------------------------------------+
//| Move trend line anchor point                                     |
//+------------------------------------------------------------------+
bool TrendPointChange(const long   chart_ID=0,       // chart's ID
                      const string name="TrendLine", // line name
                      const int    point_index=0,    // anchor point index
                      datetime     time=0,           // anchor point time coordinate
                      double       price=0)          // anchor point price coordinate
  {
//--- if point position is not set, move it to the current bar having Bid price
   if(!time)
      time=TimeCurrent();
   if(!price)
      price=SymbolInfoDouble(Symbol(),SYMBOL_BID);
//--- reset the error value
   ResetLastError();
//--- move trend line's anchor point
   if(!ObjectMove(chart_ID,name,point_index,time,price))
     {
      Print(__FUNCTION__,
            ": failed to move the anchor point! Error code = ",GetLastError());
      return(false);
     }
//--- successful execution
   return(true);
  }
//+------------------------------------------------------------------+
//| Check the values of trend line's anchor points and set default   |
//| values for empty ones                                            |
//+------------------------------------------------------------------+
void ChangeTrendEmptyPoints(datetime &time1,double &price1,
                            datetime &time2,double &price2)
  {
//--- if the first point's time is not set, it will be on the current bar
   if(!time1)
      time1=TimeCurrent();
//--- if the first point's price is not set, it will have Bid value
   if(!price1)
      price1=SymbolInfoDouble(Symbol(),SYMBOL_BID);
//--- if the second point's time is not set, it is located 9 bars left from the second one
   if(!time2)
     {
      //--- array for receiving the open time of the last 10 bars
      datetime temp[10];
      CopyTime(Symbol(),Period(),time1,10,temp);
      //--- set the second point 9 bars left from the first one
      time2=temp[0];
     }
//--- if the second point's price is not set, it is equal to the first point's one
   if(!price2)
      price2=price1;
  }
//+------------------------------------------------------------------+