Supertrend [trugurpala]

//@version=6
// Supertrend — ATR-Based Trend Direction — github.com/trugurpala/pinescriptv6
// Author: Ugur Pala · mail@ugurpala.com
indicator("Supertrend [trugurpala]", overlay=true)

// ── Inputs ───────────────────────────────────────────────────────────────────
int   atrLen  = input.int(10,   "ATR Length",     minval=1)
float atrMult = input.float(3.0, "ATR Multiplier", step=0.1)

// ── Calculations ─────────────────────────────────────────────────────────────
float atr       = ta.atr(atrLen)
float upperBand = hl2 + atrMult * atr
float lowerBand = hl2 - atrMult * atr

var float superTrend = na
var int   direction  = 1

float prevUpper = nz(upperBand[1], upperBand)
float prevLower = nz(lowerBand[1], lowerBand)

upperBand := upperBand < prevUpper or close[1] > prevUpper ? upperBand : prevUpper
lowerBand := lowerBand > prevLower or close[1] < prevLower ? lowerBand : prevLower

if close > nz(superTrend[1], 0)
    superTrend := lowerBand
    direction  := 1
else
    superTrend := upperBand
    direction  := -1

bool bullSwitch = direction ==  1 and direction[1] == -1
bool bearSwitch = direction == -1 and direction[1] ==  1

// ── Visuals ──────────────────────────────────────────────────────────────────
color trendColor = direction == 1 ? color.green : color.red
plot(superTrend, "Supertrend", trendColor, linewidth=3)
plotshape(bullSwitch, "Bull", shape.triangleup,   location.belowbar, color.green, size=size.normal)
plotshape(bearSwitch, "Bear", shape.triangledown, location.abovebar, color.red,   size=size.normal)
bgcolor(direction == 1 ? color.new(color.green, 94) : color.new(color.red, 94))

// ── Alerts ───────────────────────────────────────────────────────────────────
alertcondition(bullSwitch, "ST Bull", "Supertrend Bull — {{ticker}} @ {{close}}")
alertcondition(bearSwitch, "ST Bear", "Supertrend Bear — {{ticker}} @ {{close}}")