VWAP Bands [trugurpala]

//@version=6
// VWAP + Standard Deviation Bands — github.com/trugurpala/pinescriptv6
// Author: Ugur Pala · mail@ugurpala.com
indicator("VWAP Bands [trugurpala]", overlay=true)

// ── Inputs ───────────────────────────────────────────────────────────────────
bool  showBands = input.bool(true, "Show Bands")
float mult1     = input.float(1.0, "Band 1 Mult", step=0.1)
float mult2     = input.float(2.0, "Band 2 Mult", step=0.1)

// ── Calculations (cumulative from day start) ─────────────────────────────────
bool isNewDay = ta.change(time("D")) != 0
var float cumVol    = 0.0
var float cumVolPx  = 0.0
var float cumVolPx2 = 0.0

if isNewDay
    cumVol    := 0.0
    cumVolPx  := 0.0
    cumVolPx2 := 0.0

cumVol    += volume
cumVolPx  += volume * hlc3
cumVolPx2 += volume * hlc3 * hlc3

float vwapVal  = cumVolPx / cumVol
float variance = cumVolPx2 / cumVol - vwapVal * vwapVal
float stdev    = math.sqrt(math.max(variance, 0))

// ── Visuals ──────────────────────────────────────────────────────────────────
plot(vwapVal, "VWAP", color.new(color.orange, 0), linewidth=2)
p1u = plot(showBands ? vwapVal + mult1 * stdev : na, "Upper 1", color.new(color.blue, 50))
p1l = plot(showBands ? vwapVal - mult1 * stdev : na, "Lower 1", color.new(color.blue, 50))
p2u = plot(showBands ? vwapVal + mult2 * stdev : na, "Upper 2", color.new(color.purple, 50))
p2l = plot(showBands ? vwapVal - mult2 * stdev : na, "Lower 2", color.new(color.purple, 50))
fill(p1u, p1l, color.new(color.blue,   93))
fill(p2u, p1u, color.new(color.purple, 93))
fill(p1l, p2l, color.new(color.purple, 93))