Ecco:

// ---------------------------------------------------------
// PRC_Echo Chamber (Pattern Projection)
// version = 0
// 04.12.2025
// Iván González @ www.prorealcode.com
// Sharing ProRealTime knowledge
// ---------------------------------------------------------

DEFPARAM DrawOnLastBarOnly = True

// --- PARAMETERS ---
// Length: Correlation window (bars to compare)
Length = 20
// Lookback: How many bars to look back in history
Lookback = 500
// ProjectionLen: How many bars to project into the future
ProjectionLen = 20

// --- INTERNAL VARIABLES ---
bestCorrelation = -1.0
bestIndex = 0
currentScale = 0.0
historyScale = 0.0

// Execute only on the last bar to optimize resources
IF islastbarupdate THEN
   
   // 1. GET CURRENT SEQUENCE
   // Fill an array with recent close prices
   $currentSeq[0] = 0
   SumX = 0.0
   SumX2 = 0.0
   
   FOR i = 0 TO Length - 1 DO
      val = Close[i]
      $currentSeq[i] = val
      
      // Prepare data for correlation (X = Current Sequence)
      SumX = SumX + val
      SumX2 = SumX2 + (val * val)
   NEXT
   
   MeanX = SumX / Length
   StDevX = SQRT((SumX2 / Length) - (MeanX * MeanX))
   
   // 2. PATTERN SEARCH
   // Iterate backwards in history to find the best match
   // Start after the current window to avoid self-comparison
   StartIndex = Length + ProjectionLen
   EndIndex = Lookback
   
   FOR k = StartIndex TO EndIndex DO
      
      SumY = 0.0
      SumY2 = 0.0
      SumXY = 0.0
      
      // Collect historical segment (Y)
      FOR j = 0 TO Length - 1 DO
         histVal = Close[k + j]
         currVal = $currentSeq[j] // Note: currentSeq[0] is current Close
         
         SumY = SumY + histVal
         SumY2 = SumY2 + (histVal * histVal)
         SumXY = SumXY + (currVal * histVal)
      NEXT
      
      // Calculate Pearson Correlation r
      MeanY = SumY / Length
      StDevY = SQRT((SumY2 / Length) - (MeanY * MeanY))
      
      // Avoid division by zero if price is flat
      IF (StDevX * StDevY) <> 0 THEN
         Covariance = (SumXY / Length) - (MeanX * MeanY)
         Correlation = Covariance / (StDevX * StDevY)
      ELSE
         Correlation = 0
      ENDIF
      
      // Save best result
      IF Correlation > bestCorrelation THEN
         bestCorrelation = Correlation
         bestIndex = k
      ENDIF
   NEXT
   
   // 4. DRAW RESULTS
   IF bestIndex > 0 THEN
      
      // A) Highlight found historical segment
      // Calculate range to draw the box
      maxH = High[bestIndex]
      minL = Low[bestIndex]
      
      FOR j = 0 TO Length - 1 DO
         maxH = MAX(maxH, High[bestIndex + j])
         minL = MIN(minL, Low[bestIndex + j])
      NEXT
      
      // Draw rectangle in the past
      x1 = BarIndex - bestIndex - Length + 1
      x2 = BarIndex - bestIndex
      
      DRAWRECTANGLE(x1, maxH, x2, minL) COLOURED(100, 200, 250, 50) BORDERCOLOR(100, 200, 250)
      DRAWTEXT("Match History", x1, maxH) ANCHOR(BOTTOM, INDEX, VALUE) COLOURED(100, 200, 250)
      
      // B) Future Projection
      // Scale historical price to current price
      // Scale factor based on ranges (High - Low of the period)
      
      rangeHist = maxH - minL
      rangeCurr = Highest[Length](High) - Lowest[Length](Low)
      
      IF rangeHist <> 0 THEN
         scaleFactor = rangeCurr / rangeHist
      ELSE
         scaleFactor = 1
      ENDIF
      
      // Anchor point (last close)
      anchorPrice = Close[0]
      histAnchor = Close[bestIndex]
      
      // Draw projection line by line
      FOR m = 1 TO ProjectionLen DO
         
         // bestIndex is the end of the pattern. The future is at bestIndex - m
         idxFuture = bestIndex - m
         
         // Stop if index is out of bounds (negative index)
         IF idxFuture < 0 THEN
            BREAK
         ENDIF
         
         priceHistFuture = Close[idxFuture]
         priceHistPrev = Close[idxFuture + 1]
         
         // Price transformation: Adjustment by scale and anchor
         // Projecting the variation
         
         price1raw = Close[bestIndex - (m - 1)]
         price2raw = Close[bestIndex - m]
         
         // Transform
         val1 = anchorPrice + (price1raw - histAnchor) * scaleFactor
         val2 = anchorPrice + (price2raw - histAnchor) * scaleFactor
         
         // X Coordinates (Future)
         xStart = BarIndex + m - 1
         xEnd = BarIndex + m
         
         DRAWSEGMENT(xStart, val1, xEnd, val2) COLOURED(255, 105, 180) STYLE(dottedline, 2)
      NEXT
      
      // 5. INFORMATION PANEL
      txtCorr = round(bestCorrelation * 100, 2)
      txtDateYear = year[bestIndex]
      txtDateMonth = month[bestIndex]
      txtDateDay = day[bestIndex]
      txtTimehour = hour[bestIndex]
      txtTimeminute = minute[bestIndex]
      
      if gettimeframe<86400 then
         DRAWTEXT("ECHO CHAMBER", -200, -100) ANCHOR(TOPRIGHT, XSHIFT, YSHIFT) COLOURED(0, 0, 0)
         DRAWTEXT("Corr.: #txtCorr#%", -200, -120) ANCHOR(TOPRIGHT, XSHIFT, YSHIFT) COLOURED(125, 125, 220)
         DRAWTEXT("Date: #txtDateYear#/#txtDateMonth#/#txtDateDay#", -200, -140) ANCHOR(TOPRIGHT, XSHIFT, YSHIFT) COLOURED(200, 200, 200)
         DRAWTEXT("Time: #txtTimehour#:#txtTimeminute#", -200, -160) ANCHOR(TOPRIGHT, XSHIFT, YSHIFT) COLOURED(200, 200, 200)
         drawrectangle(-290, -80, -110, -180)ANCHOR(TOPRIGHT, XSHIFT, YSHIFT)
      else
         DRAWTEXT("ECHO CHAMBER", -200, -100) ANCHOR(TOPRIGHT, XSHIFT, YSHIFT) COLOURED(0, 0, 0)
         DRAWTEXT("Corr.: #txtCorr#%", -200, -120) ANCHOR(TOPRIGHT, XSHIFT, YSHIFT) COLOURED(125, 125, 220)
         DRAWTEXT("Date: #txtDateYear#/#txtDateMonth#/#txtDateDay#", -200, -140) ANCHOR(TOPRIGHT, XSHIFT, YSHIFT) COLOURED(200, 200, 200)
         drawrectangle(-290, -80, -110, -160)ANCHOR(TOPRIGHT, XSHIFT, YSHIFT)
      endif
   ENDIF
   
   
ENDIF

RETURN