//+------------------------------------------------------------------+
//|                                              Adaptive Trend Flow |
//|                                     QuantAlgo (Converted by AI)  |
//+------------------------------------------------------------------+
#property indicator_chart_window
#property indicator_buffers 4
#property indicator_color1 Blue
#property indicator_color2 Red
#property indicator_color3 Lime
#property indicator_color4 Orange

/* 
Converting a Pine Script indicator to MQL4 involves a complete rewrite of the
script, as the two languages differ significantly in syntax, structure, and
function calls. Below is an MQL4 script that mirrors the functionality of the
provided Pine Script to the best possible extent.

Adaptive Trend Flow

This MQL4 script creates an indicator resembling the Pine Script logic. Some
Pine Script features, like background gradients and advanced label placement,
are challenging to replicate directly in MQL4 due to platform limitations. You
might need to further customize the script based on your specific requirements.
 */

input int MainLength = 10;         // Main Length
input int SmoothingLength = 14;   // Smoothing Length
input double Sensitivity = 2.0;   // Sensitivity
input color BullishColor = Lime;  // Bullish Color
input color BearishColor = Red;   // Bearish Color
input bool ColorBars = true;      // Enable Bar Coloring
input bool BackgroundColor = true; // Enable Background Coloring

// Buffers
double BasisBuffer[];
double UpperBuffer[];
double LowerBuffer[];
double LevelBuffer[];

int OnInit()
{
   // Set up indicator buffers
   SetIndexBuffer(0, BasisBuffer);
   SetIndexBuffer(1, UpperBuffer);
   SetIndexBuffer(2, LowerBuffer);
   SetIndexBuffer(3, LevelBuffer);

   IndicatorShortName("Adaptive Trend Flow [QuantAlgo]");
   return(INIT_SUCCEEDED);
}

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 <= MainLength * 2 || rates_total <= SmoothingLength)
      return(0);

   for (int i = prev_calculated; i < rates_total; i++)
   {
      double Typical = (high[i] + low[i] + close[i]) / 3.0;
      double FastEMA = iMAOnArray(&Typical, rates_total, MainLength, 0, MODE_EMA, i);
      double SlowEMA = iMAOnArray(&Typical, rates_total, MainLength * 2, 0, MODE_EMA, i);
      double Basis = (FastEMA + SlowEMA) / 2.0;

      double Volatility = iStdDevOnArray(&Typical, rates_total, MainLength, 0, i);
      double SmoothedVolatility = iMAOnArray(&Volatility, rates_total, SmoothingLength, 0, MODE_EMA, i);

      double Upper = Basis + SmoothedVolatility * Sensitivity;
      double Lower = Basis - SmoothedVolatility * Sensitivity;

      BasisBuffer[i] = Basis;
      UpperBuffer[i] = Upper;
      LowerBuffer[i] = Lower;

      // Trend Calculation
      if (i > 0)
      {
         if (close[i] > Basis)
            LevelBuffer[i] = Lower;
         else
            LevelBuffer[i] = Upper;
      }

      // Bar and Background Coloring (if enabled)
      if (ColorBars)
      {
         Color barColor = (close[i] > Basis) ? BullishColor : BearishColor;
         SetBarColor(i, barColor);
      }

      if (BackgroundColor)
      {
         Color bgColor = (close[i] > Basis) ? BullishColor : BearishColor;
         SetBackgroundColor(i, bgColor);
      }
   }

   return(rates_total);
}

void SetBarColor(int index, color col)
{
   // Custom function to set bar color (implementation depends on platform support)
}

void SetBackgroundColor(int index, color col)
{
   // Custom function to set background color (implementation depends on platform support)
}