//+------------------------------------------------------------------+
//|                                                           Atr.mqh|
//|                                       Copyright 2026, bandersoft |
//|                               https://www.mql5.com/en/users/fats |
//+------------------------------------------------------------------+
//|                                                                  |
//|  Average True Range helper.                                      |
//|                                                                  |
//+------------------------------------------------------------------+
#ifndef STOPFIRST_ATR_MQH
#define STOPFIRST_ATR_MQH

//--- GetATRPips reports its result via PriceToPips
#include "Symbol.mqh"

//+------------------------------------------------------------------+
//| Average True Range on one symbol, timeframe and period            |
//|                                                                   |
//| Calling iATR, CopyBuffer and IndicatorRelease on every request   |
//| is expensive once per tick, and a handle created moments earlier |
//| usually has no calculated data yet, so CopyBuffer fails and the  |
//| result is a silent 0 the caller cannot tell from a real reading. |
//|                                                                   |
//| The handle is created once and held for the object's lifetime.     |
//|                                                                   |
//|   CAtr atr;                                                        |
//|   int OnInit()  { return atr.Init(_Symbol, PERIOD_H1, 14) ? 0 : 1; }|
//|   void OnTick() { double d = atr.Pips(); }                         |
//+------------------------------------------------------------------+
class CAtr
{
private:
   string            m_symbol;
   ENUM_TIMEFRAMES   m_timeframe;
   int               m_period;
   int               m_handle;

public:
                     CAtr(void);
                    ~CAtr(void);
   bool              Init(const string symbol = "",
                          const ENUM_TIMEFRAMES timeframe = PERIOD_CURRENT,
                          const int period = 14);
   double            Value(const int shift = 0);
   double            Pips(const int shift = 0);
   void              Release(void);
   bool              IsReady(void) const { return m_handle != INVALID_HANDLE; }
   int               Handle(void)  const { return m_handle; }
};

CAtr::CAtr(void) : m_symbol(_Symbol),
                   m_timeframe(PERIOD_CURRENT),
                   m_period(14),
                   m_handle(INVALID_HANDLE)
{
}

CAtr::~CAtr(void)
{
   Release();
}

//+------------------------------------------------------------------+
//| Release the handle, if one is held                                |
//| Returns: nothing.                                                 |
//+------------------------------------------------------------------+
void CAtr::Release(void)
{
   if(m_handle != INVALID_HANDLE)
   {
      IndicatorRelease(m_handle);
      m_handle = INVALID_HANDLE;
   }
}

//+------------------------------------------------------------------+
//| Create the indicator handle                                       |
//| Parameters:                                                       |
//|   symbol - empty for the current chart symbol                    |
//|   timeframe - PERIOD_CURRENT for the chart timeframe             |
//|   period - ATR averaging period, must be positive                |
//|                                                                   |
//| Returns: true if the handle was created. Safe to call again to    |
//|          repoint the object; the previous handle is released.     |
//+------------------------------------------------------------------+
bool CAtr::Init(const string symbol, const ENUM_TIMEFRAMES timeframe, const int period)
{
   Release();

   if(period <= 0) return false;

   m_symbol    = (symbol == "") ? _Symbol : symbol;
   m_timeframe = timeframe;
   m_period    = period;
   m_handle    = iATR(m_symbol, m_timeframe, m_period);

   return m_handle != INVALID_HANDLE;
}

//+------------------------------------------------------------------+
//| ATR in price units                                                |
//| Parameters:                                                       |
//|   shift - bar to read, 0 being the forming bar                   |
//|                                                                   |
//| Returns: the ATR, or 0 if Init was never called, the handle       |
//|          failed, or the indicator has not calculated yet. A       |
//|          freshly created handle needs a few ticks; retry rather   |
//|          than treating the 0 as a reading.                        |
//+------------------------------------------------------------------+
double CAtr::Value(const int shift)
{
   if(m_handle == INVALID_HANDLE || shift < 0) return 0.0;

   double buffer[];
   ArraySetAsSeries(buffer, true);

   if(CopyBuffer(m_handle, 0, shift, 1, buffer) <= 0) return 0.0;

   return buffer[0];
}

//+------------------------------------------------------------------+
//| ATR expressed in pips                                             |
//| Returns: the ATR in pips, or 0 - see Value().                     |
//+------------------------------------------------------------------+
double CAtr::Pips(const int shift)
{
   double value = Value(shift);
   if(value <= 0) return 0.0;

   return PriceToPips(value, m_symbol);
}

//+------------------------------------------------------------------+
//| Cache backing the GetATRPips wrapper                              |
//|                                                                   |
//| Parallel primitive arrays rather than an array of CAtr: MQL5       |
//| reports undeleted dynamic objects when a program unloads, and a    |
//| file-scope cache has no destructor to clean up in. Handles are     |
//| released by the terminal at unload, or explicitly by               |
//| ReleaseAtrCache().                                                 |
//+------------------------------------------------------------------+
string g_atrKeys[];
int    g_atrHandles[];

//+------------------------------------------------------------------+
//| Release every handle the GetATRPips cache holds                   |
//| Returns: nothing. Call from OnDeinit if you want them gone early. |
//+------------------------------------------------------------------+
void ReleaseAtrCache(void)
{
   int total = ArraySize(g_atrHandles);
   for(int i = 0; i < total; i++)
      if(g_atrHandles[i] != INVALID_HANDLE)
         IndicatorRelease(g_atrHandles[i]);

   ArrayResize(g_atrKeys, 0);
   ArrayResize(g_atrHandles, 0);
}

//+------------------------------------------------------------------+
//| Cached iATR handle for one symbol, timeframe and period           |
//| Returns: the handle, or INVALID_HANDLE if it could not be made.   |
//+------------------------------------------------------------------+
int CachedAtrHandle(const string symbol, const ENUM_TIMEFRAMES timeframe, const int period)
{
   string key = symbol + "|" + IntegerToString(timeframe) + "|" + IntegerToString(period);

   int total = ArraySize(g_atrKeys);
   for(int i = 0; i < total; i++)
      if(g_atrKeys[i] == key)
         return g_atrHandles[i];

   int handle = iATR(symbol, timeframe, period);
   if(handle == INVALID_HANDLE) return INVALID_HANDLE;

   ArrayResize(g_atrKeys, total + 1);
   ArrayResize(g_atrHandles, total + 1);
   g_atrKeys[total]    = key;
   g_atrHandles[total] = handle;

   return handle;
}

//+------------------------------------------------------------------+
//| Get ATR value in pips                                             |
//| Parameters:                                                       |
//|   period - ATR averaging period                                  |
//|   timeframe - PERIOD_CURRENT for the chart timeframe             |
//|   symbol - empty for the current chart symbol                    |
//|                                                                   |
//| Kept as a wrapper over the cache so existing callers do not have  |
//| to hold a CAtr. Prefer CAtr in new code - it makes the handle's   |
//| lifetime visible.                                                 |
//|                                                                   |
//| Returns: the ATR in pips, or 0 if the handle could not be made    |
//|          or the indicator has not calculated yet.                 |
//+------------------------------------------------------------------+
double GetATRPips(int period = 14, ENUM_TIMEFRAMES timeframe = PERIOD_CURRENT,
                  string symbol = "")
{
   if(symbol == "") symbol = _Symbol;
   if(period <= 0) return 0;

   int handle = CachedAtrHandle(symbol, timeframe, period);
   if(handle == INVALID_HANDLE) return 0;

   double atr[];
   ArraySetAsSeries(atr, true);

   if(CopyBuffer(handle, 0, 0, 1, atr) <= 0) return 0;

   return PriceToPips(atr[0], symbol);
}

#endif // STOPFIRST_ATR_MQH
//+------------------------------------------------------------------+