//+------------------------------------------------------------------+
//|                                      Indicator: Example_0001.mq5 |
//|                                       Created with EABuilder.com |
//|                                        https://www.eabuilder.com |
//+------------------------------------------------------------------+
#property copyright "Created with EABuilder.com"
#property link      "https://www.eabuilder.com"
#property version   "1.00"
#property description ""

//--- indicator settings
#property indicator_chart_window
#property indicator_buffers 1
#property indicator_plots 1

#property indicator_type1 DRAW_ARROW
#property indicator_width1 1
#property indicator_color1 0xFFAA00
#property indicator_label1 "Buy"

#define PLOT_MAXIMUM_BARS_BACK 5000
#define OMIT_OLDEST_BARS 50

//--- indicator buffers
double Buffer1[];

input int Fast_Triple = 14;
input int Slow_Doble = 25;
datetime time_alert; //used when sending alert
double myPoint; //initialized in OnInit
int TEMA_handle;
double TEMA[];
int DEMA_handle;
double DEMA[];
double Low[];

void myAlert(string type, string message)
  {
   if(type == "print")
      Print(message);
   else if(type == "error")
     {
      Print(type+" | Example_0001 @ "+Symbol()+","+IntegerToString(Period())+" | "+message);
     }
   else if(type == "order")
     {
     }
   else if(type == "modify")
     {
     }
   else if(type == "indicator")
     {
      Print(type+" | Example_0001 @ "+Symbol()+","+IntegerToString(Period())+" | "+message);
     }
  }

//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int OnInit()
  {   
   SetIndexBuffer(0, Buffer1);
   PlotIndexSetDouble(0, PLOT_EMPTY_VALUE, EMPTY_VALUE);
   PlotIndexSetInteger(0, PLOT_DRAW_BEGIN, MathMax(Bars(Symbol(), PERIOD_CURRENT)-PLOT_MAXIMUM_BARS_BACK+1, OMIT_OLDEST_BARS+1));
   PlotIndexSetInteger(0, PLOT_ARROW, 241);
   //initialize myPoint
   myPoint = Point();
   if(Digits() == 5 || Digits() == 3)
     {
      myPoint *= 10;
     }
   TEMA_handle = iTEMA(NULL, PERIOD_CURRENT, Fast_Triple, 0, PRICE_CLOSE);
   if(TEMA_handle < 0)
     {
      Print("The creation of iTEMA has failed: TEMA_handle=", INVALID_HANDLE);
      Print("Runtime error = ", GetLastError());
      return(INIT_FAILED);
     }
   
   DEMA_handle = iDEMA(NULL, PERIOD_CURRENT, Slow_Doble, 0, PRICE_CLOSE);
   if(DEMA_handle < 0)
     {
      Print("The creation of iDEMA has failed: DEMA_handle=", INVALID_HANDLE);
      Print("Runtime error = ", GetLastError());
      return(INIT_FAILED);
     }
   
   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[])
  {
   int limit = rates_total - prev_calculated;
   //--- counting from 0 to rates_total
   ArraySetAsSeries(Buffer1, true);
   //--- initial zero
   if(prev_calculated < 1)
     {
      ArrayInitialize(Buffer1, EMPTY_VALUE);
     }
   else
      limit++;
   datetime Time[];
   
   if(BarsCalculated(TEMA_handle) <= 0) 
      return(0);
   if(CopyBuffer(TEMA_handle, 0, 0, rates_total, TEMA) <= 0) return(rates_total);
   ArraySetAsSeries(TEMA, true);
   if(BarsCalculated(DEMA_handle) <= 0) 
      return(0);
   if(CopyBuffer(DEMA_handle, 0, 0, rates_total, DEMA) <= 0) return(rates_total);
   ArraySetAsSeries(DEMA, true);
   if(CopyLow(Symbol(), PERIOD_CURRENT, 0, rates_total, Low) <= 0) return(rates_total);
   ArraySetAsSeries(Low, true);
   if(CopyTime(Symbol(), Period(), 0, rates_total, Time) <= 0) return(rates_total);
   ArraySetAsSeries(Time, true);
   //--- main loop
   for(int i = limit-1; i >= 0; i--)
     {
      if (i >= MathMin(PLOT_MAXIMUM_BARS_BACK-1, rates_total-1-OMIT_OLDEST_BARS)) continue; //omit some old rates to prevent "Array out of range" or slow calculation   
      
      //Indicator Buffer 1
      if(TEMA[i] > DEMA[i]
      && TEMA[i+1] < DEMA[i+1] //Triple Exponential Moving Average crosses above Double Exponential Moving Average
      )
        {
         Buffer1[i] = Low[i]; //Set indicator value at Candlestick Low
         if(i == 0 && Time[0] != time_alert) { myAlert("indicator", "Buy"); time_alert = Time[0]; } //Instant alert, only once per bar
        }
      else
        {
         Buffer1[i] = EMPTY_VALUE;
        }
     }
   return(rates_total);
  }
//+------------------------------------------------------------------+