MACD MQL5 Indicator: Custom Histogram, Alerts & EA Code Guide

//+------------------------------------------------------------------+
//|  MACD_Custom.mq5                                                 |
//|  Complete MACD indicator with histogram, alerts and EA logic     |
//|  Compatible with MetaTrader 5 / MQL5 5.x                        |
//+------------------------------------------------------------------+
#property copyright "Pineify — pineify.app"
#property link      "https://pineify.app"
#property version   "1.00"
#property strict

//--- Indicator / EA mode switch
#property indicator_separate_window
#property indicator_buffers 4
#property indicator_plots   3

//--- Plot 0 : MACD histogram
#property indicator_label1  "Histogram"
#property indicator_type1   DRAW_HISTOGRAM
#property indicator_color1  clrDodgerBlue
#property indicator_style1  STYLE_SOLID
#property indicator_width1  2

//--- Plot 1 : MACD line
#property indicator_label2  "MACD"
#property indicator_type2   DRAW_LINE
#property indicator_color2  clrRed
#property indicator_style2  STYLE_SOLID
#property indicator_width2  1

//--- Plot 2 : Signal line
#property indicator_label3  "Signal"
#property indicator_type3   DRAW_LINE
#property indicator_color3  clrOrange
#property indicator_style3  STYLE_DOT
#property indicator_width3  1

//--- Input parameters
input int    InpFastEMA   = 12;       // Fast EMA period
input int    InpSlowEMA   = 26;       // Slow EMA period
input int    InpSignalSMA = 9;        // Signal SMA period
input bool   InpAlerts    = true;     // Enable push / alert notifications
input bool   InpEAMode    = false;    // Run as EA (trade on signals)
input double InpLotSize   = 0.10;     // EA lot size
input int    InpStopPips  = 30;       // EA stop-loss in pips
input int    InpTakePips  = 60;       // EA take-profit in pips
input ulong  InpMagic     = 202400;   // EA magic number

//--- Indicator buffers
double BufferHistogram[];
double BufferMACD[];
double BufferSignal[];
double BufferDummy[];   // required internal buffer for iMACD handle

//--- Global handles and state
int    g_macdHandle   = INVALID_HANDLE;
bool   g_lastCrossUp  = false;
bool   g_lastCrossDown= false;
datetime g_lastAlert  = 0;

//+------------------------------------------------------------------+
//| Custom indicator / EA initialisation                             |
//+------------------------------------------------------------------+
int OnInit()
  {
   //--- Create MACD handle using MQL5 handle pattern
   g_macdHandle = iMACD(_Symbol, _Period,
                         InpFastEMA, InpSlowEMA, InpSignalSMA,
                         PRICE_CLOSE);
   if(g_macdHandle == INVALID_HANDLE)
     {
      Print("ERROR: iMACD handle creation failed. Code=", GetLastError());
      return INIT_FAILED;
     }

   //--- Bind indicator buffers in correct index order
   //    iMACD returns: 0=MACD line, 1=Signal line
   SetIndexBuffer(0, BufferHistogram, INDICATOR_DATA);
   SetIndexBuffer(1, BufferMACD,      INDICATOR_DATA);
   SetIndexBuffer(2, BufferSignal,    INDICATOR_DATA);
   SetIndexBuffer(3, BufferDummy,     INDICATOR_CALCULATIONS);

   //--- Label the indicator window
   IndicatorSetString(INDICATOR_SHORTNAME,
                      StringFormat("MACD(%d,%d,%d)",
                                   InpFastEMA, InpSlowEMA, InpSignalSMA));
   IndicatorSetInteger(INDICATOR_DIGITS, _Digits + 1);

   //--- Reset cross-state tracking
   g_lastCrossUp   = false;
   g_lastCrossDown = false;

   Print("MACD_Custom: initialised on ", _Symbol, " / ", EnumToString(_Period));
   return INIT_SUCCEEDED;
  }

//+------------------------------------------------------------------+
//| Indicator / EA calculation on every new tick or bar              |
//+------------------------------------------------------------------+
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(rates_total < InpSlowEMA + InpSignalSMA)
      return 0;

   int limit = rates_total - prev_calculated;
   if(prev_calculated > 0) limit++;

   //--- Copy MACD and Signal values from the built-in handle
   double macdArr[];
   double signalArr[];
   if(CopyBuffer(g_macdHandle, 0, 0, limit, macdArr)  <= 0) return prev_calculated;
   if(CopyBuffer(g_macdHandle, 1, 0, limit, signalArr) <= 0) return prev_calculated;

   //--- Fill indicator buffers (most-recent bar = index 0 in CopyBuffer)
   for(int i = 0; i < limit && (rates_total - 1 - i) >= 0; i++)
     {
      int dst = rates_total - 1 - i;
      BufferMACD[dst]      = macdArr[i];
      BufferSignal[dst]    = signalArr[i];
      BufferHistogram[dst] = macdArr[i] - signalArr[i];
     }

   //--- Alert / EA logic on the most-recent completed bar (index 1 to avoid repainting)
   if(rates_total >= 2 && prev_calculated > 0)
     {
      double macdPrev   = BufferMACD[rates_total - 2];
      double macdCurr   = BufferMACD[rates_total - 1];
      double signalPrev = BufferSignal[rates_total - 2];
      double signalCurr = BufferSignal[rates_total - 1];

      bool crossUp   = (macdPrev < signalPrev) && (macdCurr >= signalCurr);
      bool crossDown = (macdPrev > signalPrev) && (macdCurr <= signalCurr);

      //--- Fire alert once per bar
      if(InpAlerts && time[rates_total - 1] != g_lastAlert)
        {
         if(crossUp)
           {
            string msg = StringFormat("%s %s — MACD Bullish Crossover @ %.5f",
                                      _Symbol, EnumToString(_Period), close[rates_total-1]);
            Alert(msg);
            SendNotification(msg);
            g_lastAlert = time[rates_total - 1];
           }
         else if(crossDown)
           {
            string msg = StringFormat("%s %s — MACD Bearish Crossover @ %.5f",
                                      _Symbol, EnumToString(_Period), close[rates_total-1]);
            Alert(msg);
            SendNotification(msg);
            g_lastAlert = time[rates_total - 1];
           }
        }

      //--- EA order management
      if(InpEAMode)
        {
         if(crossUp  && !g_lastCrossUp)   OpenTrade(ORDER_TYPE_BUY,  close[rates_total-1]);
         if(crossDown && !g_lastCrossDown) OpenTrade(ORDER_TYPE_SELL, close[rates_total-1]);
        }

      g_lastCrossUp   = crossUp;
      g_lastCrossDown = crossDown;
     }

   return rates_total;
  }

//+------------------------------------------------------------------+
//| Place a market order using MQL5 MqlTradeRequest                  |
//+------------------------------------------------------------------+
void OpenTrade(ENUM_ORDER_TYPE orderType, double price)
  {
   //--- Close any existing position in the opposite direction first
   ClosePreviousTrades(orderType);

   double point = SymbolInfoDouble(_Symbol, SYMBOL_POINT);
   double pipVal = point * 10.0;   // standard 5-digit broker

   double sl, tp;
   if(orderType == ORDER_TYPE_BUY)
     {
      sl = price - InpStopPips  * pipVal;
      tp = price + InpTakePips  * pipVal;
     }
   else
     {
      sl = price + InpStopPips  * pipVal;
      tp = price - InpTakePips  * pipVal;
     }

   MqlTradeRequest request = {};
   MqlTradeResult  result  = {};

   request.action    = TRADE_ACTION_DEAL;
   request.symbol    = _Symbol;
   request.volume    = InpLotSize;
   request.type      = orderType;
   request.price     = price;
   request.sl        = NormalizeDouble(sl, _Digits);
   request.tp        = NormalizeDouble(tp, _Digits);
   request.deviation = 10;
   request.magic     = InpMagic;
   request.comment   = "MACD_Custom";
   request.type_filling = ORDER_FILLING_FOK;

   if(!OrderSend(request, result))
      Print("OrderSend failed: ", result.retcode, " — ", result.comment);
   else
      Print("Order placed: ticket=", result.order, " type=",
            EnumToString(orderType), " price=", price);
  }

//+------------------------------------------------------------------+
//| Close all EA positions opposite to the new direction             |
//+------------------------------------------------------------------+
void ClosePreviousTrades(ENUM_ORDER_TYPE newType)
  {
   for(int i = PositionsTotal() - 1; i >= 0; i--)
     {
      ulong ticket = PositionGetTicket(i);
      if(ticket == 0) continue;
      if(PositionGetString(POSITION_SYMBOL) != _Symbol) continue;
      if((ulong)PositionGetInteger(POSITION_MAGIC) != InpMagic) continue;

      ENUM_POSITION_TYPE posType = (ENUM_POSITION_TYPE)PositionGetInteger(POSITION_TYPE);
      bool shouldClose = (newType == ORDER_TYPE_BUY  && posType == POSITION_TYPE_SELL) ||
                         (newType == ORDER_TYPE_SELL && posType == POSITION_TYPE_BUY);
      if(!shouldClose) continue;

      MqlTradeRequest req = {};
      MqlTradeResult  res = {};
      req.action    = TRADE_ACTION_DEAL;
      req.symbol    = _Symbol;
      req.position  = ticket;
      req.volume    = PositionGetDouble(POSITION_VOLUME);
      req.type      = (posType == POSITION_TYPE_BUY) ? ORDER_TYPE_SELL : ORDER_TYPE_BUY;
      req.price     = (req.type == ORDER_TYPE_SELL)
                      ? SymbolInfoDouble(_Symbol, SYMBOL_BID)
                      : SymbolInfoDouble(_Symbol, SYMBOL_ASK);
      req.deviation = 10;
      req.magic     = InpMagic;
      req.comment   = "MACD_Custom_Close";
      req.type_filling = ORDER_FILLING_FOK;
      OrderSend(req, res);
     }
  }

//+------------------------------------------------------------------+
//| OnTick — required entry point even when using OnCalculate        |
//+------------------------------------------------------------------+
void OnTick()
  {
   // Main logic runs inside OnCalculate.
   // OnTick is required for EAs compiled without indicator_separate_window.
  }

//+------------------------------------------------------------------+
//| Clean up indicator handle on removal                             |
//+------------------------------------------------------------------+
void OnDeinit(const int reason)
  {
   if(g_macdHandle != INVALID_HANDLE)
     {
      IndicatorRelease(g_macdHandle);
      g_macdHandle = INVALID_HANDLE;
     }
   Print("MACD_Custom: deactivated. Reason code=", reason);
  }
//+------------------------------------------------------------------+