Supertrend Strategy [trugurpala]

//@version=6
// Supertrend Trend Following — github.com/trugurpala/pinescriptv6
// Author: Ugur Pala · mail@ugurpala.com
strategy("Supertrend Strategy [trugurpala]",
    overlay=true, initial_capital=10000,
    default_qty_type=strategy.percent_of_equity, default_qty_value=10,
    commission_type=strategy.commission.percent, commission_value=0.1)

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

// ── Supertrend ───────────────────────────────────────────────────────────────
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

// ── Entries ──────────────────────────────────────────────────────────────────
if bullSwitch
    strategy.close("Short")
    strategy.entry("Long", strategy.long)
if bearSwitch and not longOnly
    strategy.close("Long")
    strategy.entry("Short", strategy.short)

// ── Visuals ──────────────────────────────────────────────────────────────────
plot(superTrend, "ST", direction == 1 ? color.green : color.red, 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)