Price Momentum Oscillator (PMO)

// Licensed under the Apache License, Version 2.0
// © mihakralj
//@version=6
indicator("Price Momentum Oscillator (PMO)", "PMO", overlay=false)

//@function Calculates Price Momentum Oscillator (DecisionPoint algorithm)
//@param src Source series to calculate PMO for
//@param time_periods First EMA smoothing period for 1-bar ROC (default 35)
//@param smooth_periods Second EMA smoothing period for PMO (default 20)
//@param signal_periods Signal line EMA period (default 10)
//@returns PMO value measuring double-smoothed momentum
pmo(series float src, simple int time_periods=35, simple int smooth_periods=20, simple int signal_periods=10)=>
    if time_periods<2 or smooth_periods<=0 or signal_periods<=0
        runtime.error("Periods must be greater than 0 (time_periods >= 2)")
    // Step 1: Always 1-bar ROC (percentage)
    float roc = bar_index > 0 and not na(src[1]) and src[1] != 0.0 ? (src / src[1] - 1.0) * 100.0 : 0.0
    // Step 2: First Custom EMA of ROC (alpha = 2/time_periods), then ×10
    float alpha1 = 2.0 / time_periods
    var float roc_ema = na
    roc_ema := na(roc_ema) ? roc : roc_ema + alpha1 * (roc - roc_ema)
    float roc_ema_scaled = roc_ema * 10.0
    // Step 3: Second Custom EMA of scaled RocEma (alpha = 2/smooth_periods) → PMO
    float alpha2 = 2.0 / smooth_periods
    var float pmo_val = na
    pmo_val := na(pmo_val) ? roc_ema_scaled : pmo_val + alpha2 * (roc_ema_scaled - pmo_val)
    pmo_val

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

// Inputs
i_source = input.source(close, "Source")
i_time_periods = input.int(35, "Time Periods (1st EMA)", minval=2)
i_smooth_periods = input.int(20, "Smooth Periods (2nd EMA)", minval=1)
i_signal_periods = input.int(10, "Signal Line Period", minval=1)

// Calculation
pmo_value = pmo(i_source, i_time_periods, i_smooth_periods, i_signal_periods)

// Signal line uses standard EMA: alpha = 2/(N+1)
float alpha_signal = 2.0 / (i_signal_periods + 1)
var float signal_line = na
signal_line := na(signal_line) ? pmo_value : signal_line + alpha_signal * (pmo_value - signal_line)

// Plot
plot(pmo_value, "PMO", color=color.blue, linewidth=2)
plot(signal_line, "Signal", color=color.red, linewidth=2)
hline(0, "Zero", color=color.gray, linestyle=hline.style_dotted)