// Licensed under the Apache License, Version 2.0
// © mihakralj
//@version=6
indicator("Moving Average Variable Period (MAVP)", "MAVP", overlay=true)

//@function Calculates EMA with per-bar variable period (TA-Lib MAVP concept)
//@param source Series to smooth
//@param period Per-bar effective period (clamped to min_period..max_period)
//@param min_period Minimum allowed period
//@param max_period Maximum allowed period
//@returns EMA value with variable alpha = 2/(period+1), compensated warmup
//@optimized Uses adaptive warmup compensator that tracks cumulative (1-alpha) product for O(1) per bar
mavp(series float source, series float period, simple int min_period, simple int max_period) =>
    var float ema = 0.0
    var float e = 1.0
    var bool warmup = true
    var float result = source
    float p = math.max(min_period, math.min(max_period, nz(period, min_period)))
    float a = 2.0 / (p + 1.0)
    float beta = 1.0 - a
    ema := a * (nz(source) - ema) + ema
    if warmup
        e *= beta
        float c = 1.0 / (1.0 - e)
        result := c * ema
        warmup := e > 1e-10
    else
        result := ema
    result

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

// Inputs
i_period = input.int(10, "Period", minval=1, tooltip="Base period for the variable-period EMA")
i_min = input.int(2, "Min Period", minval=1, tooltip="Minimum allowed period")
i_max = input.int(30, "Max Period", minval=2, tooltip="Maximum allowed period")
i_source = input.source(close, "Source")

// Per-bar period series: fixed here, replace with any series for adaptive behavior
// In the C# implementation, this is an external per-bar series input
float per_bar_period = float(i_period)

// Calculation
mavp_value = mavp(i_source, per_bar_period, i_min, i_max)

// Plot
plot(mavp_value, "MAVP", color=color.yellow, linewidth=2)