//+------------------------------------------------------------------+
//|                                                supertrendPro.mq5 |
//|          Copyright 2026, MetaQuotes Ltd. Developer: Gloria Diana |
//|                        https://www.mql5.com/en/users/gloriadiana |
//+------------------------------------------------------------------+
#property copyright "Copyright 2026, MetaQuotes Ltd. Developer is Chacha Ian"
#property link      "https://www.mql5.com/en/users/chachaian"
#property version   "1.00"

#property indicator_chart_window
#property indicator_buffers 8
#property indicator_plots   3

#property indicator_type1   DRAW_COLOR_CANDLES
#property indicator_type2   DRAW_LINE
#property indicator_type3   DRAW_LINE

//+------------------------------------------------------------------+
//| Input parameters                                                 |
//+------------------------------------------------------------------+
input group "Supertrend Settings"
input int    InpATRPeriod     = 10;   // ATR calculation period
input double InpATRMultiplier = 1.5;  // ATR multiplier used to position the Supertrend bands

input group "Notifications"
input bool InpEnablePushNotifications = true;   // Send mobile push notifications on confirmed trend changes

//+------------------------------------------------------------------+
//| Trend states exposed through Buffer 7                            |
//+------------------------------------------------------------------+
const double TREND_BULLISH =  1.0;   // Confirmed bullish trend
const double TREND_BEARISH =  0.0;   // Confirmed bearish trend
const double TREND_NEUTRAL = -1.0;   // Initial unresolved trend state

//+------------------------------------------------------------------+
//| Indicator theme colors                                           |
//+------------------------------------------------------------------+
const color COLOR_BACKGROUND = clrWhiteSmoke;   // Main chart background
const color COLOR_FOREGROUND = clrBlack;        // Chart text and scale labels
const color COLOR_BULLISH    = clrSeaGreen;     // Bullish candles, bands, and Bid line
const color COLOR_BEARISH    = clrCrimson;      // Bearish candles, bands, and Ask line

//+------------------------------------------------------------------+
//| Stores the chart appearance before Supertrend Pro changes it     |
//+------------------------------------------------------------------+
struct SChartAppearance
  {
   long              backgroundColor;      // Original chart background color
   long              foregroundColor;      // Original chart text and scale color
   long              showGrid;             // Original grid visibility
   long              chartMode;            // Original chart drawing mode
   long              chartUpColor;         // Original bullish chart color
   long              chartDownColor;       // Original bearish chart color
   long              candleBullColor;      // Original bullish candle color
   long              candleBearColor;      // Original bearish candle color
   long              bidColor;             // Original Bid line color
   long              askColor;             // Original Ask line color
  };

//+------------------------------------------------------------------+
//| Global variables                                                 |
//+------------------------------------------------------------------+
int    g_atrHandle = INVALID_HANDLE;  // Handle of the ATR indicator
double g_atrValues[];                 // Working array for copied ATR values
SChartAppearance g_chartAppearance;          // Chart appearance saved before applying the theme
bool             g_chartAppearanceSaved = false; // Confirms that restoration data is available
datetime g_lastNotifiedBarTime = 0;   // Open time of the last bar that generated a push notification
datetime g_lastObservedLiveBarTime = 0;   // Live bar tracked during the previous successful calculation

//+------------------------------------------------------------------+
//| Public indicator buffers                                         |
//+------------------------------------------------------------------+
double g_candleOpen[];      // Buffer 0: trend-colored candle Open
double g_candleHigh[];      // Buffer 1: trend-colored candle High
double g_candleLow[];       // Buffer 2: trend-colored candle Low
double g_candleClose[];     // Buffer 3: trend-colored candle Close
double g_candleColor[];     // Buffer 4: candle trend color index

double g_upperBand[];       // Buffer 5: upper/bearish Supertrend band
double g_lowerBand[];       // Buffer 6: lower/bullish Supertrend band

double g_trendState[];      // Buffer 7: 1.0 bullish, 0.0 bearish, -1.0 neutral

//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int OnInit()
  {
//--- Validate all user-configurable Supertrend parameters before
//--- allocating or configuring indicator resources.
   if(!ValidateInputs())
      return(INIT_PARAMETERS_INCORRECT);

//--- Reset notification tracking so every initialization establishes
//--- a fresh live-bar baseline before any push alert can be generated.
   g_lastNotifiedBarTime=0;
   g_lastObservedLiveBarTime=0;

//--- Bind the declared arrays to their permanent indicator buffer
//--- indexes before configuring their visual plots.
   if(!ConfigureIndicatorBuffers())
     {
      Print("Failed to configure Supertrend Pro indicator buffers.");
      return(INIT_FAILED);
     }

//--- Configure the candle and Supertrend plots that present the
//--- calculated trend state on the chart.
   if(!ConfigureIndicatorPlots())
     {
      Print("Failed to configure Supertrend Pro indicator plots.");
      return(INIT_FAILED);
     }

//--- Create the ATR handle used by the Supertrend calculation.
   g_atrHandle=iATR(_Symbol,PERIOD_CURRENT,InpATRPeriod);
   if(g_atrHandle==INVALID_HANDLE)
     {
      PrintFormat("Failed to create ATR handle. Error=%d",GetLastError());
      return(INIT_FAILED);
     }

//--- Preserve the user's current chart appearance before applying
//--- the mandatory Supertrend Pro visual theme.
   if(!SaveChartAppearance())
     {
      Print("Failed to save the current chart appearance.");
      return(INIT_FAILED);
     }

//--- Apply the Supertrend Pro theme after the original appearance
//--- has been stored successfully.
   if(!ApplyIndicatorTheme())
     {
      Print("Failed to apply the Supertrend Pro chart theme.");

      //--- Restore any chart properties changed before theme setup failed.
      RestoreChartAppearance();
      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[])
  {
//--- Explicitly use chronological indexing throughout the indicator.
   ArraySetAsSeries(time,false);
   ArraySetAsSeries(open,false);
   ArraySetAsSeries(high,false);
   ArraySetAsSeries(low,false);
   ArraySetAsSeries(close,false);
   ArraySetAsSeries(tick_volume,false);
   ArraySetAsSeries(volume,false);
   ArraySetAsSeries(spread,false);

//--- Wait until enough price history exists to calculate the ATR.
   if(rates_total<InpATRPeriod)
      return(prev_calculated);

//--- Separate the forming bar from the latest confirmed bar.
   int liveIndex=rates_total-1;
   int lastClosedIndex=rates_total-2;
   int firstValidIndex=InpATRPeriod-1;
   int start=0;

   if(lastClosedIndex<firstValidIndex)
      return(prev_calculated);

//--- A notification is eligible only when exactly one new bar has
//--- opened since the previous successful calculation and the bar that
//--- has just closed was previously tracked as the live bar.
   bool liveTrendChange=false;

   if(prev_calculated>0 &&
      rates_total==prev_calculated+1 &&
      g_lastObservedLiveBarTime!=0 &&
      time[lastClosedIndex]==g_lastObservedLiveBarTime)
      liveTrendChange=true;

//--- Rebuild the complete Supertrend state when previous calculations
//--- cannot be reused. Historical reconstruction never generates alerts.
   if(prev_calculated==0)
     {
      //--- Clear all public buffers before reconstructing history.
      ArrayInitialize(g_candleOpen,EMPTY_VALUE);
      ArrayInitialize(g_candleHigh,EMPTY_VALUE);
      ArrayInitialize(g_candleLow,EMPTY_VALUE);
      ArrayInitialize(g_candleClose,EMPTY_VALUE);
      ArrayInitialize(g_candleColor,0.0);
      ArrayInitialize(g_upperBand,EMPTY_VALUE);
      ArrayInitialize(g_lowerBand,EMPTY_VALUE);
      ArrayInitialize(g_trendState,EMPTY_VALUE);

      //--- ATR data is required from the first valid seed bar onward.
      start=firstValidIndex;
     }
   else
     {
      //--- Resume from the bar that was live during the previous
      //--- calculation and may now have become confirmed.
      start=prev_calculated-1;

      if(start<firstValidIndex+1)
         start=firstValidIndex+1;
     }

//--- Copy ATR values only for confirmed bars that require calculation.
   if(start<=lastClosedIndex)
     {
      if(!GetATRValues(start,lastClosedIndex,rates_total))
         return(prev_calculated);
     }

//--- Seed the neutral state only during a complete historical rebuild.
   if(prev_calculated==0)
     {
      double barMidpoint=(high[firstValidIndex]+low[firstValidIndex])/2.0;

      g_upperBand[firstValidIndex]=barMidpoint+
                                   g_atrValues[firstValidIndex]*InpATRMultiplier;
      g_lowerBand[firstValidIndex]=barMidpoint-
                                   g_atrValues[firstValidIndex]*InpATRMultiplier;
      g_trendState[firstValidIndex]=TREND_NEUTRAL;

      //--- The seed bar is complete, so subsequent bars can enter
      //--- the unified Supertrend state machine.
      start=firstValidIndex+1;
     }

//--- Process every newly confirmed bar through the common Supertrend
//--- state machine, including any bars recovered after inactivity.
   for(int i=start;i<=lastClosedIndex;i++)
      CalculateBar(i,open,high,low,close);

//--- Notify only when the newest confirmed bar was genuinely observed
//--- forming during the preceding successful indicator calculation.
   if(liveTrendChange)
      NotifyConfirmedTrendChange(lastClosedIndex,time);

//--- Keep the forming bar outside the confirmed indicator state.
   g_candleOpen[liveIndex]=EMPTY_VALUE;
   g_candleHigh[liveIndex]=EMPTY_VALUE;
   g_candleLow[liveIndex]=EMPTY_VALUE;
   g_candleClose[liveIndex]=EMPTY_VALUE;
   g_candleColor[liveIndex]=0.0;
   g_upperBand[liveIndex]=EMPTY_VALUE;
   g_lowerBand[liveIndex]=EMPTY_VALUE;
   g_trendState[liveIndex]=EMPTY_VALUE;

//--- Record the current live bar only after this calculation completes
//--- successfully. It becomes eligible for notification after it closes.
   g_lastObservedLiveBarTime=time[liveIndex];

   return(rates_total);
  }

//+------------------------------------------------------------------+
//| Custom indicator deinitialization function                       |
//+------------------------------------------------------------------+
void OnDeinit(const int reason)
  {
//--- Restore the user's previous chart appearance before the
//--- Supertrend Pro instance leaves the chart.
   if(g_chartAppearanceSaved)
      RestoreChartAppearance();

//--- Release the ATR resource only when a valid handle was created.
   if(g_atrHandle!=INVALID_HANDLE)
     {
      IndicatorRelease(g_atrHandle);
      g_atrHandle=INVALID_HANDLE;
     }
  }

//+------------------------------------------------------------------+
//| Validates the Supertrend input parameters                        |
//+------------------------------------------------------------------+
bool ValidateInputs()
  {
//--- The ATR period must contain at least one bar.
   if(InpATRPeriod < 1)
     {
      Print("Invalid ATR period. InpATRPeriod must be greater than or equal to 1.");
      return(false);
     }

//--- The ATR multiplier must be positive because zero or negative
//--- values cannot produce valid Supertrend band distances.
   if(InpATRMultiplier <= 0.0)
     {
      Print("Invalid ATR multiplier. InpATRMultiplier must be greater than 0.");
      return(false);
     }

   return(true);
  }

//+------------------------------------------------------------------+
//| Binds all arrays to their permanent indicator buffer indexes     |
//+------------------------------------------------------------------+
bool ConfigureIndicatorBuffers()
  {
//--- Buffers 0-3 provide the OHLC values required by the
//--- DRAW_COLOR_CANDLES plot used for trend-colored candles.
   if(!SetIndexBuffer(0,g_candleOpen,INDICATOR_DATA))
     {
      Print("Failed to bind candle Open buffer. Error: ",GetLastError());
      return(false);
     }

   if(!SetIndexBuffer(1,g_candleHigh,INDICATOR_DATA))
     {
      Print("Failed to bind candle High buffer. Error: ",GetLastError());
      return(false);
     }

   if(!SetIndexBuffer(2,g_candleLow,INDICATOR_DATA))
     {
      Print("Failed to bind candle Low buffer. Error: ",GetLastError());
      return(false);
     }

   if(!SetIndexBuffer(3,g_candleClose,INDICATOR_DATA))
     {
      Print("Failed to bind candle Close buffer. Error: ",GetLastError());
      return(false);
     }

//--- Buffer 4 stores the color index used to select the bullish
//--- or bearish candle color for each calculated bar.
   if(!SetIndexBuffer(4,g_candleColor,INDICATOR_COLOR_INDEX))
     {
      Print("Failed to bind candle color buffer. Error: ",GetLastError());
      return(false);
     }

//--- Buffers 5 and 6 remain separate so bearish and bullish
//--- Supertrend segments are never visually joined at reversals.
   if(!SetIndexBuffer(5,g_upperBand,INDICATOR_DATA))
     {
      Print("Failed to bind upper Supertrend band buffer. Error: ",GetLastError());
      return(false);
     }

   if(!SetIndexBuffer(6,g_lowerBand,INDICATOR_DATA))
     {
      Print("Failed to bind lower Supertrend band buffer. Error: ",GetLastError());
      return(false);
     }

//--- Buffer 7 exposes the numerical trend state for programmatic
//--- access by Expert Advisors and other MQL5 applications.
   if(!SetIndexBuffer(7,g_trendState,INDICATOR_DATA))
     {
      Print("Failed to bind trend-state buffer. Error: ",GetLastError());
      return(false);
     }

//--- Explicitly keep every indicator buffer in chronological order.
//--- Index 0 represents the oldest available bar and higher indexes
//--- progress toward the current bar.
   if(!ArraySetAsSeries(g_candleOpen,false) ||
      !ArraySetAsSeries(g_candleHigh,false) ||
      !ArraySetAsSeries(g_candleLow,false) ||
      !ArraySetAsSeries(g_candleClose,false) ||
      !ArraySetAsSeries(g_candleColor,false) ||
      !ArraySetAsSeries(g_upperBand,false) ||
      !ArraySetAsSeries(g_lowerBand,false) ||
      !ArraySetAsSeries(g_trendState,false))
     {
      Print("Failed to configure chronological indexing for indicator buffers.");
      return(false);
     }

   return(true);
  }

//+------------------------------------------------------------------+
//| Applies the Supertrend Pro visual theme to the chart             |
//+------------------------------------------------------------------+
bool ApplyIndicatorTheme()
  {
//--- Apply the neutral chart background and foreground colors.
   if(!ChartSetInteger(0,CHART_COLOR_BACKGROUND,COLOR_BACKGROUND))
     {
      PrintFormat("Failed to set chart background color. Error=%d",GetLastError());
      return(false);
     }

   if(!ChartSetInteger(0,CHART_COLOR_FOREGROUND,COLOR_FOREGROUND))
     {
      PrintFormat("Failed to set chart foreground color. Error=%d",GetLastError());
      return(false);
     }

//--- Remove the chart grid to keep the trend candles and Supertrend
//--- bands visually dominant against the WhiteSmoke background.
   if(!ChartSetInteger(0,CHART_SHOW_GRID,false))
     {
      PrintFormat("Failed to configure chart grid visibility. Error=%d",GetLastError());
      return(false);
     }

//--- Use candle-chart mode throughout the Supertrend Pro presentation.
   if(!ChartSetInteger(0,CHART_MODE,CHART_CANDLES))
     {
      PrintFormat("Failed to set candle chart mode. Error=%d",GetLastError());
      return(false);
     }

//--- Apply the bullish theme to native bullish chart elements.
   if(!ChartSetInteger(0,CHART_COLOR_CHART_UP,COLOR_BULLISH))
     {
      PrintFormat("Failed to set bullish chart color. Error=%d",GetLastError());
      return(false);
     }

   if(!ChartSetInteger(0,CHART_COLOR_CANDLE_BULL,COLOR_BULLISH))
     {
      PrintFormat("Failed to set bullish candle color. Error=%d",GetLastError());
      return(false);
     }

//--- Apply the bearish theme to native bearish chart elements.
   if(!ChartSetInteger(0,CHART_COLOR_CHART_DOWN,COLOR_BEARISH))
     {
      PrintFormat("Failed to set bearish chart color. Error=%d",GetLastError());
      return(false);
     }

   if(!ChartSetInteger(0,CHART_COLOR_CANDLE_BEAR,COLOR_BEARISH))
     {
      PrintFormat("Failed to set bearish candle color. Error=%d",GetLastError());
      return(false);
     }

//--- Match Bid and Ask line colors to the directional theme.
   if(!ChartSetInteger(0,CHART_COLOR_BID,COLOR_BULLISH))
     {
      PrintFormat("Failed to set Bid line color. Error=%d",GetLastError());
      return(false);
     }

   if(!ChartSetInteger(0,CHART_COLOR_ASK,COLOR_BEARISH))
     {
      PrintFormat("Failed to set Ask line color. Error=%d",GetLastError());
      return(false);
     }

//--- Refresh the chart after applying the complete visual theme.
   ChartRedraw(0);

   return(true);
  }

//+------------------------------------------------------------------+
//| Saves the chart appearance before applying the indicator theme   |
//+------------------------------------------------------------------+
bool SaveChartAppearance()
  {
//--- Read the chart colors that Supertrend Pro will temporarily replace.
   if(!ChartGetInteger(0,CHART_COLOR_BACKGROUND,0,g_chartAppearance.backgroundColor))
     {
      PrintFormat("Failed to read chart background color. Error=%d",GetLastError());
      return(false);
     }

   if(!ChartGetInteger(0,CHART_COLOR_FOREGROUND,0,g_chartAppearance.foregroundColor))
     {
      PrintFormat("Failed to read chart foreground color. Error=%d",GetLastError());
      return(false);
     }

   if(!ChartGetInteger(0,CHART_COLOR_CHART_UP,0,g_chartAppearance.chartUpColor))
     {
      PrintFormat("Failed to read bullish chart color. Error=%d",GetLastError());
      return(false);
     }

   if(!ChartGetInteger(0,CHART_COLOR_CHART_DOWN,0,g_chartAppearance.chartDownColor))
     {
      PrintFormat("Failed to read bearish chart color. Error=%d",GetLastError());
      return(false);
     }

   if(!ChartGetInteger(0,CHART_COLOR_CANDLE_BULL,0,g_chartAppearance.candleBullColor))
     {
      PrintFormat("Failed to read bullish candle color. Error=%d",GetLastError());
      return(false);
     }

   if(!ChartGetInteger(0,CHART_COLOR_CANDLE_BEAR,0,g_chartAppearance.candleBearColor))
     {
      PrintFormat("Failed to read bearish candle color. Error=%d",GetLastError());
      return(false);
     }

   if(!ChartGetInteger(0,CHART_COLOR_BID,0,g_chartAppearance.bidColor))
     {
      PrintFormat("Failed to read Bid line color. Error=%d",GetLastError());
      return(false);
     }

   if(!ChartGetInteger(0,CHART_COLOR_ASK,0,g_chartAppearance.askColor))
     {
      PrintFormat("Failed to read Ask line color. Error=%d",GetLastError());
      return(false);
     }

//--- Preserve the non-color chart properties changed by the theme.
   if(!ChartGetInteger(0,CHART_SHOW_GRID,0,g_chartAppearance.showGrid))
     {
      PrintFormat("Failed to read chart grid visibility. Error=%d",GetLastError());
      return(false);
     }

   if(!ChartGetInteger(0,CHART_MODE,0,g_chartAppearance.chartMode))
     {
      PrintFormat("Failed to read chart mode. Error=%d",GetLastError());
      return(false);
     }

//--- The complete appearance snapshot is now safe to restore later.
   g_chartAppearanceSaved=true;

   return(true);
  }

//+------------------------------------------------------------------+
//| Restores the chart appearance saved before theme application     |
//+------------------------------------------------------------------+
bool RestoreChartAppearance()
  {
   bool restored=true;

//--- Restore the original background and foreground colors.
   if(!ChartSetInteger(0,CHART_COLOR_BACKGROUND,g_chartAppearance.backgroundColor))
     {
      PrintFormat("Failed to restore chart background color. Error=%d",GetLastError());
      restored=false;
     }

   if(!ChartSetInteger(0,CHART_COLOR_FOREGROUND,g_chartAppearance.foregroundColor))
     {
      PrintFormat("Failed to restore chart foreground color. Error=%d",GetLastError());
      restored=false;
     }

//--- Restore the original grid visibility and chart drawing mode.
   if(!ChartSetInteger(0,CHART_SHOW_GRID,g_chartAppearance.showGrid))
     {
      PrintFormat("Failed to restore chart grid visibility. Error=%d",GetLastError());
      restored=false;
     }

   if(!ChartSetInteger(0,CHART_MODE,g_chartAppearance.chartMode))
     {
      PrintFormat("Failed to restore chart mode. Error=%d",GetLastError());
      restored=false;
     }

//--- Restore the original bullish chart and candle colors.
   if(!ChartSetInteger(0,CHART_COLOR_CHART_UP,g_chartAppearance.chartUpColor))
     {
      PrintFormat("Failed to restore bullish chart color. Error=%d",GetLastError());
      restored=false;
     }

   if(!ChartSetInteger(0,CHART_COLOR_CANDLE_BULL,g_chartAppearance.candleBullColor))
     {
      PrintFormat("Failed to restore bullish candle color. Error=%d",GetLastError());
      restored=false;
     }

//--- Restore the original bearish chart and candle colors.
   if(!ChartSetInteger(0,CHART_COLOR_CHART_DOWN,g_chartAppearance.chartDownColor))
     {
      PrintFormat("Failed to restore bearish chart color. Error=%d",GetLastError());
      restored=false;
     }

   if(!ChartSetInteger(0,CHART_COLOR_CANDLE_BEAR,g_chartAppearance.candleBearColor))
     {
      PrintFormat("Failed to restore bearish candle color. Error=%d",GetLastError());
      restored=false;
     }

//--- Restore the original Bid and Ask line colors.
   if(!ChartSetInteger(0,CHART_COLOR_BID,g_chartAppearance.bidColor))
     {
      PrintFormat("Failed to restore Bid line color. Error=%d",GetLastError());
      restored=false;
     }

   if(!ChartSetInteger(0,CHART_COLOR_ASK,g_chartAppearance.askColor))
     {
      PrintFormat("Failed to restore Ask line color. Error=%d",GetLastError());
      restored=false;
     }

//--- Refresh the chart after restoring all saved appearance properties.
   ChartRedraw(0);

//--- Clear the saved-state flag only after a successful restoration.
   if(restored)
      g_chartAppearanceSaved=false;

   return(restored);
  }

//+------------------------------------------------------------------+
//| Configures the visual plots used by Supertrend Pro               |
//+------------------------------------------------------------------+
bool ConfigureIndicatorPlots()
  {
//--- Configure Plot 0 as two-color candles. Color index 0 represents
//--- bearish candles and color index 1 represents bullish candles.
   if(!PlotIndexSetInteger(0,PLOT_DRAW_TYPE,DRAW_COLOR_CANDLES))
     {
      PrintFormat("Failed to set the candle plot type. Error=%d",GetLastError());
      return(false);
     }

   if(!PlotIndexSetInteger(0,PLOT_COLOR_INDEXES,2))
     {
      PrintFormat("Failed to configure candle color indexes. Error=%d",GetLastError());
      return(false);
     }

   if(!PlotIndexSetInteger(0,PLOT_LINE_COLOR,0,COLOR_BEARISH))
     {
      PrintFormat("Failed to set bearish candle color. Error=%d",GetLastError());
      return(false);
     }

   if(!PlotIndexSetInteger(0,PLOT_LINE_COLOR,1,COLOR_BULLISH))
     {
      PrintFormat("Failed to set bullish candle color. Error=%d",GetLastError());
      return(false);
     }

   if(!PlotIndexSetDouble(0,PLOT_EMPTY_VALUE,EMPTY_VALUE))
     {
      PrintFormat("Failed to set the candle plot empty value. Error=%d",GetLastError());
      return(false);
     }

   if(!PlotIndexSetString(0,PLOT_LABEL,
                          "Supertrend Open;Supertrend High;Supertrend Low;Supertrend Close"))
     {
      PrintFormat("Failed to set the candle plot label. Error=%d",GetLastError());
      return(false);
     }

//--- Configure Plot 1 as the bearish upper Supertrend band.
   if(!PlotIndexSetInteger(1,PLOT_DRAW_TYPE,DRAW_LINE))
     {
      PrintFormat("Failed to set upper Supertrend plot type. Error=%d",GetLastError());
      return(false);
     }

   if(!PlotIndexSetInteger(1,PLOT_LINE_STYLE,STYLE_SOLID))
     {
      PrintFormat("Failed to set upper Supertrend line style. Error=%d",GetLastError());
      return(false);
     }

   if(!PlotIndexSetInteger(1,PLOT_LINE_WIDTH,2))
     {
      PrintFormat("Failed to set upper Supertrend line width. Error=%d",GetLastError());
      return(false);
     }

   if(!PlotIndexSetInteger(1,PLOT_LINE_COLOR,COLOR_BEARISH))
     {
      PrintFormat("Failed to set upper Supertrend line color. Error=%d",GetLastError());
      return(false);
     }

   if(!PlotIndexSetDouble(1,PLOT_EMPTY_VALUE,EMPTY_VALUE))
     {
      PrintFormat("Failed to set upper Supertrend empty value. Error=%d",GetLastError());
      return(false);
     }

   if(!PlotIndexSetString(1,PLOT_LABEL,"Bearish Supertrend"))
     {
      PrintFormat("Failed to set upper Supertrend plot label. Error=%d",GetLastError());
      return(false);
     }

//--- Configure Plot 2 as the bullish lower Supertrend band.
   if(!PlotIndexSetInteger(2,PLOT_DRAW_TYPE,DRAW_LINE))
     {
      PrintFormat("Failed to set lower Supertrend plot type. Error=%d",GetLastError());
      return(false);
     }

   if(!PlotIndexSetInteger(2,PLOT_LINE_STYLE,STYLE_SOLID))
     {
      PrintFormat("Failed to set lower Supertrend line style. Error=%d",GetLastError());
      return(false);
     }

   if(!PlotIndexSetInteger(2,PLOT_LINE_WIDTH,2))
     {
      PrintFormat("Failed to set lower Supertrend line width. Error=%d",GetLastError());
      return(false);
     }

   if(!PlotIndexSetInteger(2,PLOT_LINE_COLOR,COLOR_BULLISH))
     {
      PrintFormat("Failed to set lower Supertrend line color. Error=%d",GetLastError());
      return(false);
     }

   if(!PlotIndexSetDouble(2,PLOT_EMPTY_VALUE,EMPTY_VALUE))
     {
      PrintFormat("Failed to set lower Supertrend empty value. Error=%d",GetLastError());
      return(false);
     }

   if(!PlotIndexSetString(2,PLOT_LABEL,"Bullish Supertrend"))
     {
      PrintFormat("Failed to set lower Supertrend plot label. Error=%d",GetLastError());
      return(false);
     }

//--- Prevent plotting before enough bars exist to produce the first
//--- ATR value required by the Supertrend calculation.
   int drawBegin=InpATRPeriod-1;

   if(!PlotIndexSetInteger(0,PLOT_DRAW_BEGIN,drawBegin) ||
      !PlotIndexSetInteger(1,PLOT_DRAW_BEGIN,drawBegin) ||
      !PlotIndexSetInteger(2,PLOT_DRAW_BEGIN,drawBegin))
     {
      PrintFormat("Failed to configure the plot starting position. Error=%d",GetLastError());
      return(false);
     }

//--- Configure the indicator identity and displayed price precision.
   if(!IndicatorSetString(INDICATOR_SHORTNAME,"Supertrend Pro"))
     {
      PrintFormat("Failed to set indicator short name. Error=%d",GetLastError());
      return(false);
     }

   if(!IndicatorSetInteger(INDICATOR_DIGITS,_Digits))
     {
      PrintFormat("Failed to set indicator precision. Error=%d",GetLastError());
      return(false);
     }

   return(true);
  }

//+------------------------------------------------------------------+
//| Copies ATR values required for the current calculation range     |
//+------------------------------------------------------------------+
bool GetATRValues(const int startIndex,
                  const int lastClosedIndex,
                  const int ratesTotal)
  {
//--- Determine how many confirmed ATR values are required.
   int valuesRequired=lastClosedIndex-startIndex+1;

   if(valuesRequired<=0)
      return(true);

//--- Confirm that the ATR handle has calculated enough recent values
//--- to cover the requested closed-bar range.
   int calculatedBars=BarsCalculated(g_atrHandle);
   if(calculatedBars<valuesRequired+1)
      return(false);

//--- Keep the persistent ATR array aligned with the complete price
//--- history so each ATR value uses the same chronological bar index.
   if(ArraySize(g_atrValues)!=ratesTotal)
     {
      if(ArrayResize(g_atrValues,ratesTotal)!=ratesTotal)
        {
         PrintFormat("Failed to resize the ATR working array to %d elements.",
                     ratesTotal);
         return(false);
        }

      if(!ArraySetAsSeries(g_atrValues,false))
        {
         Print("Failed to configure chronological indexing for ATR values.");
         return(false);
        }
     }

//--- Create a temporary array for only the recent ATR values required
//--- by this calculation pass.
   double atrValues[];

   if(ArrayResize(atrValues,valuesRequired)!=valuesRequired)
     {
      PrintFormat("Failed to resize the temporary ATR array to %d elements.",
                  valuesRequired);
      return(false);
     }

   ArraySetAsSeries(atrValues,false);

//--- Start from shift 1 because the current live bar is intentionally
//--- excluded from confirmed Supertrend calculations.
   ResetLastError();

   int copiedValues=CopyBuffer(g_atrHandle,0,1,valuesRequired,atrValues);
   if(copiedValues<0)
     {
      PrintFormat("Failed to copy ATR values. Error=%d",GetLastError());
      return(false);
     }

//--- A partial copy means the requested ATR range is not fully ready.
   if(copiedValues!=valuesRequired)
      return(false);

//--- Transfer the copied ATR segment into its matching chronological
//--- positions in the persistent ATR working array.
   for(int i=0;i<valuesRequired;i++)
      g_atrValues[startIndex+i]=atrValues[i];

   return(true);
  }

//+------------------------------------------------------------------+
//| Calculates one bar according to the previous Supertrend state    |
//+------------------------------------------------------------------+
void CalculateBar(const int index,
                  const double &open[],
                  const double &high[],
                  const double &low[],
                  const double &close[])
  {
   int previousIndex=index-1;

//--- Continue resolving the initial neutral state until price
//--- establishes the first confirmed directional trend.
   if(g_trendState[previousIndex]==TREND_NEUTRAL)
     {
      CalculateNeutralState(index,high,low,close);

      //--- Color the bar only after the neutral state resolves into
      //--- a confirmed bullish or bearish trend.
      if(g_trendState[index]==TREND_BULLISH)
         SetBullishCandle(index,open,high,low,close);
      else
         if(g_trendState[index]==TREND_BEARISH)
            SetBearishCandle(index,open,high,low,close);

      return;
     }

//--- Apply bullish continuation or bearish reversal logic when the
//--- preceding confirmed bar belongs to an established bullish trend.
   if(g_trendState[previousIndex]==TREND_BULLISH)
     {
      CalculateBullishState(index,open,high,low,close);
      return;
     }

//--- Apply bearish continuation or bullish reversal logic when the
//--- preceding confirmed bar belongs to an established bearish trend.
   if(g_trendState[previousIndex]==TREND_BEARISH)
      CalculateBearishState(index,open,high,low,close);
  }

//+------------------------------------------------------------------+
//| Processes one bar while the Supertrend state remains neutral     |
//+------------------------------------------------------------------+
bool CalculateNeutralState(const int index,
                           const double &high[],
                           const double &low[],
                           const double &close[])
  {
//--- Calculate the raw ATR-based bands for the current closed bar.
   double barMidpoint=(high[index]+low[index])/2.0;
   double upperBandValue=barMidpoint+
                         g_atrValues[index]*InpATRMultiplier;
   double lowerBandValue=barMidpoint-
                         g_atrValues[index]*InpATRMultiplier;

   int previousIndex=index-1;

//--- Establish the first bullish trend when price closes above the
//--- previous neutral upper band.
   if(close[index]>g_upperBand[previousIndex])
     {
      g_trendState[index]=TREND_BULLISH;
      g_upperBand[index]=EMPTY_VALUE;
      g_lowerBand[index]=lowerBandValue;

      return(true);
     }

//--- Establish the first bearish trend when price closes below the
//--- previous neutral lower band.
   if(close[index]<g_lowerBand[previousIndex])
     {
      g_trendState[index]=TREND_BEARISH;
      g_lowerBand[index]=EMPTY_VALUE;
      g_upperBand[index]=upperBandValue;

      return(true);
     }

//--- Keep the state neutral while price remains between both bands.
//--- The upper band may only move downward during this stage.
   if(upperBandValue<g_upperBand[previousIndex])
      g_upperBand[index]=upperBandValue;
   else
      g_upperBand[index]=g_upperBand[previousIndex];

//--- The lower band may only move upward while the initial trend
//--- remains unresolved.
   if(lowerBandValue>g_lowerBand[previousIndex])
      g_lowerBand[index]=lowerBandValue;
   else
      g_lowerBand[index]=g_lowerBand[previousIndex];

//--- Preserve the neutral state until either boundary is breached.
   g_trendState[index]=TREND_NEUTRAL;

   return(false);
  }

//+------------------------------------------------------------------+
//| Processes one bar when the previous trend state is bullish       |
//+------------------------------------------------------------------+
void CalculateBullishState(const int index,
                           const double &open[],
                           const double &high[],
                           const double &low[],
                           const double &close[])
  {
//--- Calculate the raw ATR-based bands for the current confirmed bar.
   double barMidpoint=(high[index]+low[index])/2.0;
   double upperBandValue=barMidpoint+
                         g_atrValues[index]*InpATRMultiplier;
   double lowerBandValue=barMidpoint-
                         g_atrValues[index]*InpATRMultiplier;

   int previousIndex=index-1;

//--- Reverse to bearish when price closes below the previous active
//--- lower band. The upper band becomes active from this bar onward.
   if(close[index]<g_lowerBand[previousIndex])
     {
      g_trendState[index]=TREND_BEARISH;
      g_lowerBand[index]=EMPTY_VALUE;
      g_upperBand[index]=upperBandValue;

      //--- Recolor the reversal bar immediately as part of the new
      //--- confirmed bearish trend.
      SetBearishCandle(index,open,high,low,close);
      return;
     }

//--- Preserve the bullish trend while allowing the lower band to
//--- tighten upward without moving back down.
   if(lowerBandValue>g_lowerBand[previousIndex])
      g_lowerBand[index]=lowerBandValue;
   else
      g_lowerBand[index]=g_lowerBand[previousIndex];

//--- Keep the bearish upper band inactive while bullish control remains.
   g_upperBand[index]=EMPTY_VALUE;
   g_trendState[index]=TREND_BULLISH;

//--- Draw the confirmed bar using the bullish candle color.
   SetBullishCandle(index,open,high,low,close);
  }

//+------------------------------------------------------------------+
//| Processes one bar when the previous trend state is bearish       |
//+------------------------------------------------------------------+
void CalculateBearishState(const int index,
                           const double &open[],
                           const double &high[],
                           const double &low[],
                           const double &close[])
  {
//--- Calculate the raw ATR-based bands for the current confirmed bar.
   double barMidpoint=(high[index]+low[index])/2.0;
   double upperBandValue=barMidpoint+
                         g_atrValues[index]*InpATRMultiplier;
   double lowerBandValue=barMidpoint-
                         g_atrValues[index]*InpATRMultiplier;

   int previousIndex=index-1;

//--- Reverse to bullish when price closes above the previous active
//--- upper band. The lower band becomes active from this bar onward.
   if(close[index]>g_upperBand[previousIndex])
     {
      g_trendState[index]=TREND_BULLISH;
      g_upperBand[index]=EMPTY_VALUE;
      g_lowerBand[index]=lowerBandValue;

      //--- Recolor the reversal bar immediately as part of the new
      //--- confirmed bullish trend.
      SetBullishCandle(index,open,high,low,close);
      return;
     }

//--- Preserve the bearish trend while allowing the upper band to
//--- tighten downward without moving back upward.
   if(upperBandValue<g_upperBand[previousIndex])
      g_upperBand[index]=upperBandValue;
   else
      g_upperBand[index]=g_upperBand[previousIndex];

//--- Keep the bullish lower band inactive while bearish control remains.
   g_lowerBand[index]=EMPTY_VALUE;
   g_trendState[index]=TREND_BEARISH;

//--- Draw the confirmed bar using the bearish candle color.
   SetBearishCandle(index,open,high,low,close);
  }

//+------------------------------------------------------------------+
//| Populates the candle buffers for a confirmed bullish bar         |
//+------------------------------------------------------------------+
void SetBullishCandle(const int index,
                      const double &open[],
                      const double &high[],
                      const double &low[],
                      const double &close[])
  {
//--- Copy the original OHLC values so the indicator can redraw the
//--- completed candle using the bullish color index.
   g_candleOpen[index]=open[index];
   g_candleHigh[index]=high[index];
   g_candleLow[index]=low[index];
   g_candleClose[index]=close[index];
   g_candleColor[index]=1.0;
  }

//+------------------------------------------------------------------+
//| Populates the candle buffers for a confirmed bearish bar         |
//+------------------------------------------------------------------+
void SetBearishCandle(const int index,
                      const double &open[],
                      const double &high[],
                      const double &low[],
                      const double &close[])
  {
//--- Copy the original OHLC values so the indicator can redraw the
//--- completed candle using the bearish color index.
   g_candleOpen[index]=open[index];
   g_candleHigh[index]=high[index];
   g_candleLow[index]=low[index];
   g_candleClose[index]=close[index];
   g_candleColor[index]=0.0;
  }

//+------------------------------------------------------------------+
//| Sends a push notification for a confirmed directional reversal   |
//+------------------------------------------------------------------+
void NotifyConfirmedTrendChange(const int index,
                                const datetime &time[])
  {
   if(!InpEnablePushNotifications)
      return;

//--- A previous confirmed bar is required to determine whether the
//--- current state represents an actual trend change.
   if(index<1)
      return;

   int previousIndex=index-1;

//--- Ignore the first directional trend established from the neutral
//--- startup state because it is not a bullish-to-bearish reversal.
   if(g_trendState[previousIndex]==TREND_NEUTRAL)
      return;

//--- Ignore bars whose directional state did not change.
   if(g_trendState[index]==g_trendState[previousIndex])
      return;

//--- Only confirmed bullish and bearish states are valid notification
//--- targets.
   if(g_trendState[index]!=TREND_BULLISH &&
      g_trendState[index]!=TREND_BEARISH)
      return;

//--- Prevent recalculation of the same confirmed bar from generating
//--- another push notification.
   if(time[index]==g_lastNotifiedBarTime)
      return;

//--- Build a concise message containing the symbol, timeframe, and
//--- newly confirmed Supertrend direction.
   string trendText=(g_trendState[index]==TREND_BULLISH) ?
                    "BULLISH" :
                    "BEARISH";

   string message=StringFormat("Supertrend | %s %s | Trend changed to %s",
                               _Symbol,
                               EnumToString((ENUM_TIMEFRAMES)_Period),
                               trendText);

//--- Send the notification and record the bar only after MetaTrader
//--- confirms that the message was accepted for delivery.
   ResetLastError();

   if(!SendNotification(message))
     {
      PrintFormat("Failed to send Supertrend push notification. Error=%d",
                  GetLastError());
      return;
     }

   g_lastNotifiedBarTime=time[index];
  }
//+------------------------------------------------------------------+