// Licensed under the Apache License, Version 2.0
// © mihakralj
//@version=6
indicator("Mode", "MODE", overlay=false)

//@function Calculates the mode (most frequent value) of a series over a lookback period.
//@param src series float Input data series.
//@param len simple int Lookback period (must be > 0).
//@returns series float The mode of the series over the period.
mode(series float src, simple int len) =>
    if len <= 0
        runtime.error("Length must be greater than 0")
    value_counts = map.new<float, int>()
    actual_lookback = math.min(len, bar_index + 1)
    for i = 0 to actual_lookback - 1
        val = src[i]
        if not na(val)
            count = na(map.get(value_counts, val)) ? 0 : map.get(value_counts, val)
            map.put(value_counts, val, count + 1)
    float mode_val = na
    int max_freq = 0
    if map.size(value_counts) > 0
        keys = map.keys(value_counts)
        for key_val in keys
            current_freq = map.get(value_counts, key_val)
            if current_freq > max_freq
                max_freq := current_freq
                mode_val := key_val
        if max_freq <= 1 and map.size(value_counts) > 1
            mode_val := na
    mode_val

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

// Inputs
i_source = input.source(close, "Source")
i_length = input.int(14, "Period", minval=1)

// Calculation
mode_value = mode(i_source, i_length)

// Plot
plot(mode_value, "Mode", color=color.new(color.green, 0, color=color.yellow, linewidth=2), linewidth=2)