// The MIT License (MIT)
// © mihakralj
//@version=6
indicator("Price Momentum Oscillator (PMO)", "PMO", overlay=false)

//@function Calculates Price Momentum Oscillator using double-smoothed ROC
//@doc https://github.com/mihakralj/pinescript/blob/main/indicators/momentum/pmo.md
//@param src Source series to calculate PMO for
//@param roc_len Lookback period for ROC calculation
//@param smooth1_len First smoothing period
//@param smooth2_len Second smoothing period
//@returns PMO value measuring smoothed momentum
pmo(series float src, simple int roc_len, simple int smooth1_len=20, simple int smooth2_len=10)=>
    if roc_len<=0 or smooth1_len<=0 or smooth2_len<=0
        runtime.error("Lengths must be greater than 0")
    float roc=100*(src-src[math.min(roc_len, bar_index)])/src[math.min(roc_len,bar_index)]
    float alpha1=2/(smooth1_len+1)
    var float smooth1=na
    smooth1:=na(smooth1)?roc:smooth1*(1-alpha1)+roc*alpha1
    float alpha2=2/(smooth2_len+1)
    var float smooth2=na
    smooth2:=na(smooth2)?smooth1:smooth2*(1-alpha2)+smooth1*alpha2
    smooth2

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

// Inputs
i_source = input.source(close, "Source")
i_roc_len = input.int(35, "ROC Length", minval=1)
i_smooth1_len = input.int(20, "First Smoothing Length", minval=1)
i_smooth2_len = input.int(10, "Second Smoothing Length", minval=1)
i_signal_len = input.int(10, "Signal Line Length", minval=1)

// Calculation
pmo_value = pmo(i_source, i_roc_len, i_smooth1_len, i_smooth2_len)
float alpha_signal = 2.0 / (i_signal_len + 1)
var float signal_line = na
signal_line := na(signal_line) ? pmo_value : signal_line * (1.0 - alpha_signal) + pmo_value * alpha_signal

// Plot
plot(pmo_value, "PMO", color=color.blue, linewidth=2)
plot(signal_line, "Signal", color=color.red, linewidth=2)