// The MIT License (MIT)
// © mihakralj
//@version=6
indicator("BRAR Indicator (BRAR)", "BRAR", overlay=false)

//@function Calculates BRAR (AR + BR) sentiment oscillators from OHLC data
//@param period Lookback period for running sums
//@returns tuple [AR, BR] where AR = atmosphere ratio, BR = buying ratio
brar(simple int period) =>
    if period <= 0
        runtime.error("Period must be greater than 0")

    var int p = math.max(1, period)
    var int head = 0
    var int count = 0

    // Four circular buffers for running sums
    var array<float> arNumBuf = array.new_float(p, na)   // HIGH - OPEN
    var array<float> arDenBuf = array.new_float(p, na)   // OPEN - LOW
    var array<float> brNumBuf = array.new_float(p, na)   // max(0, HIGH - prevClose)
    var array<float> brDenBuf = array.new_float(p, na)   // max(0, prevClose - LOW)

    var float arNumSum = 0.0
    var float arDenSum = 0.0
    var float brNumSum = 0.0
    var float brDenSum = 0.0

    float prevClose = nz(close[1], open)

    // Current bar components
    float arNum = high - open
    float arDen = open - low
    float brNum = math.max(0.0, high - prevClose)
    float brDen = math.max(0.0, prevClose - low)

    // Remove oldest values from running sums
    float oldArNum = array.get(arNumBuf, head)
    float oldArDen = array.get(arDenBuf, head)
    float oldBrNum = array.get(brNumBuf, head)
    float oldBrDen = array.get(brDenBuf, head)

    if not na(oldArNum)
        arNumSum -= oldArNum
        arDenSum -= oldArDen
        brNumSum -= oldBrNum
        brDenSum -= oldBrDen
    else
        count := math.min(count + 1, p)

    // Add current values to running sums
    arNumSum += arNum
    arDenSum += arDen
    brNumSum += brNum
    brDenSum += brDen

    // Store in circular buffers
    array.set(arNumBuf, head, arNum)
    array.set(arDenBuf, head, arDen)
    array.set(brNumBuf, head, brNum)
    array.set(brDenBuf, head, brDen)
    head := (head + 1) % p

    // Calculate AR and BR ratios (* 100)
    float ar = arDenSum != 0.0 ? (arNumSum / arDenSum) * 100.0 : 0.0
    float br = brDenSum != 0.0 ? (brNumSum / brDenSum) * 100.0 : 0.0

    [ar, br]

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

// Inputs
i_period = input.int(26, "Period", minval=1, maxval=500)

// Calculation
[ar_value, br_value] = brar(i_period)

// Plot
plot(ar_value, "AR", color.new(color.yellow, 0), 2)
plot(br_value, "BR", color.new(color.aqua, 0), 2)
hline(100, "Reference", color=color.gray, linestyle=hline.style_dotted)