//@version=5
strategy("BTC Trend Rider [ATR Breakout]", overlay=true,
     initial_capital=10000, currency=currency.USD,
     default_qty_type=strategy.fixed, default_qty_value=1,
     commission_type=strategy.commission.percent, commission_value=0.1,
     slippage=2, pyramiding=0, calc_on_every_tick=false)

// ── Inputs ────────────────────────────────────────────────
grpT = "Trend"
fastLen  = input.int(21,  "Fast EMA",  minval=1, group=grpT)
slowLen  = input.int(50,  "Slow EMA",  minval=1, group=grpT)
trendLen = input.int(200, "Trend EMA", minval=1, group=grpT)
adxLen   = input.int(14,  "ADX Length", minval=1, group=grpT)
adxMin   = input.float(20, "Min ADX", minval=0, group=grpT)

grpE = "Entry"
donLen    = input.int(20, "Breakout Lookback", minval=2, group=grpE)
useShorts = input.bool(false, "Enable Shorts", group=grpE)

grpR = "Risk"
atrLen    = input.int(14,    "ATR Length", minval=1, group=grpR)
slMult    = input.float(2.0, "Initial Stop (ATR x)", minval=0.1, step=0.1, group=grpR)
trailMult = input.float(3.0, "Trailing Stop (ATR x)", minval=0.1, step=0.1, group=grpR)
riskPct   = input.float(1.0, "Risk per Trade (% equity)", minval=0.1, maxval=100, step=0.1, group=grpR)

grpD = "Backtest Window"
startTime = input.time(timestamp("2018-01-01T00:00:00"), "Start", group=grpD)
endTime   = input.time(timestamp("2099-12-31T00:00:00"), "End",   group=grpD)
inWindow  = time >= startTime and time <= endTime

// ── Indicators ────────────────────────────────────────────
emaFast  = ta.ema(close, fastLen)
emaSlow  = ta.ema(close, slowLen)
emaTrend = ta.ema(close, trendLen)
atr      = ta.atr(atrLen)
[diPlus, diMinus, adx] = ta.dmi(adxLen, adxLen)
donHigh  = ta.highest(high, donLen)[1]
donLow   = ta.lowest(low, donLen)[1]

trendUp   = close > emaTrend and emaFast > emaSlow
trendDown = close < emaTrend and emaFast < emaSlow
strong    = adx > adxMin

longSignal  = inWindow and trendUp and strong and close > donHigh
shortSignal = inWindow and useShorts and trendDown and strong and close < donLow

// ── Position sizing (risk-based, no leverage) ─────────────
stopDist = atr * slMult
rawQty   = stopDist > 0 ? (strategy.equity * riskPct / 100) / stopDist : 0.0
maxQty   = strategy.equity / close
qty      = math.min(rawQty, maxQty)

// ── Stop state ────────────────────────────────────────────
var float longStop  = na
var float shortStop = na

flat = strategy.position_size == 0

if flat and longSignal and qty > 0
    longStop := close - stopDist
    strategy.entry("Long", strategy.long, qty=qty)

if flat and shortSignal and qty > 0
    shortStop := close + stopDist
    strategy.entry("Short", strategy.short, qty=qty)

// Ratchet trailing stops (only move in trade's favor)
if strategy.position_size > 0
    longStop := math.max(nz(longStop, close - stopDist), close - atr * trailMult)
    strategy.exit("L-Stop", from_entry="Long", stop=longStop)
    if close < emaSlow
        strategy.close("Long", comment="Trend break")

if strategy.position_size < 0
    shortStop := math.min(nz(shortStop, close + stopDist), close + atr * trailMult)
    strategy.exit("S-Stop", from_entry="Short", stop=shortStop)
    if close > emaSlow
        strategy.close("Short", comment="Trend break")

// Reset stops when flat with no pending entry
if flat and not longSignal
    longStop := na
if flat and not shortSignal
    shortStop := na

// Close everything at end of window
if not inWindow and not flat
    strategy.close_all(comment="Window end")

// ── Visuals ───────────────────────────────────────────────
plot(emaFast,  "Fast EMA",  color=color.new(color.aqua, 0))
plot(emaSlow,  "Slow EMA",  color=color.new(color.orange, 0))
plot(emaTrend, "Trend EMA", color=color.new(color.gray, 0), linewidth=2)
plot(strategy.position_size > 0 ? longStop  : na, "Long Stop",  color=color.red,   style=plot.style_linebr, linewidth=2)
plot(strategy.position_size < 0 ? shortStop : na, "Short Stop", color=color.green, style=plot.style_linebr, linewidth=2)
bgcolor(trendUp ? color.new(color.green, 92) : trendDown ? color.new(color.red, 92) : na, title="Regime")
plotshape(longSignal  and flat, "Long Signal",  shape.triangleup,   location.belowbar, color.green, size=size.small)
plotshape(shortSignal and flat, "Short Signal", shape.triangledown, location.abovebar, color.red,   size=size.small)