// Licensed under the Apache License, Version 2.0
// © mihakralj
//@version=6
indicator("Chaikin's Volatility (CVI)", "CVI", overlay=false)

//@function Calculates Chaikin's Volatility using high-low range and ROC of EMA
//@param roc_length Period for Rate of Change calculation
//@param smooth_length Period for EMA smoothing
//@returns float Volatility value measuring change in trading ranges
//@optimized for performance using efficient range ROC calculation
cvi(simple int roc_length, simple int smooth_length) =>
    var float prevEma = 0.0
    hlRange = high - low
    alpha = 2.0 / (smooth_length + 1)
    if bar_index == 0
        float sum = 0.0
        for i = 0 to smooth_length-1
            sum += nz(hlRange[i])
        prevEma := sum/smooth_length
    ema = nz(prevEma)
    ema := (hlRange - ema) * alpha + ema
    prevEma := ema
    float roc = na
    if bar_index >= roc_length
        roc := ((ema - ema[roc_length])/ema[roc_length]) * 100
    roc

// ---------- Main loop ----------

// Inputs
i_roc = input.int(10, "ROC Length", minval=1, maxval=500, tooltip="Period for Rate of Change calculation")
i_smooth = input.int(10, "Smoothing Length", minval=1, maxval=500, tooltip="Period for EMA smoothing of high-low range")

// Calculation
cviValue = cvi(i_roc, i_smooth)

// Plot
plot(cviValue, "CVI", color=color.yellow, linewidth=2)
plot(0, "Zero", color.gray, 1, plot.style_circles)