I am Trying to code for trailing stop loss in my strategy, but it doesn't work

Question

I Tried adding Trailing stop loss in my strategy but, it doesn't seem to work, the position always closes below it's entry price, Please have a look, The strategy works fine, buy and sell signals are to the point.

I don't know what I am doing wrong. I tried adding take profit(targetPrice), and start a trailing stop loss from that target price.

Here is my code

//@version=4
strategy("Sanky Strategy", overlay=true)

a = input(1, title="Key Value. 'This changes the sensitivity'")
c = input(10, title="ATR Period")
h = input(false, title="Signals from Heikin Ashi Candles")
profit_target_percent = input(0.5, title="Profit Target (%)")
stop_loss = input(0.8, title="Stop Loss (%)")


xATR = atr(c)
nLoss = a * xATR

src = h ? security(heikinashi(syminfo.tickerid), timeframe.period, close, lookahead=false) : close

xATRTrailingStop = 0.0
xATRTrailingStop := iff(src > nz(xATRTrailingStop[1], 0) and src[1] > nz(xATRTrailingStop[1], 0), max(nz(xATRTrailingStop[1]), src - nLoss),
   iff(src < nz(xATRTrailingStop[1], 0) and src[1] < nz(xATRTrailingStop[1], 0), min(nz(xATRTrailingStop[1]), src + nLoss),
   iff(src > nz(xATRTrailingStop[1], 0), src - nLoss, src + nLoss)))

pos = 0
pos := iff(src[1] < nz(xATRTrailingStop[1], 0) and src > nz(xATRTrailingStop[1], 0), 1,
   iff(src[1] > nz(xATRTrailingStop[1], 0) and src < nz(xATRTrailingStop[1], 0), -1, nz(pos[1], 0)))

xcolor = pos == -1 ? color.red : pos == 1 ? color.green : color.blue

ema = ema(src, 1)
above = crossover(ema, xATRTrailingStop)
below = crossover(xATRTrailingStop, ema)

buy = src > xATRTrailingStop and above
sell = src < xATRTrailingStop and below

barbuy = src > xATRTrailingStop
barsell = src < xATRTrailingStop

strategy.entry("long", true, when=buy)
strategy.entry("short", false, when=sell)

// code to manage position size and profit targets
var float entryPrice = na
var float targetPrice = na
var float stoploss = na

if (buy)
    entryPrice := src
    targetPrice := entryPrice * (1 + profit_target_percent / 100)
    stoploss := entryPrice * (1- stop_loss/100)
if (sell)
    entryPrice := src
    targetPrice := entryPrice * (1 - profit_target_percent / 100)
    stoploss := entryPrice * (1+ stop_loss/100)



plotshape(buy, title="Buy", text='Buy', style=shape.labelup, location=location.belowbar, color=color.green, textcolor=color.white, transp=0, size=size.tiny)
plotshape(sell, title="Sell", text='Sell', style=shape.labeldown, location=location.abovebar, color=color.red, textcolor=color.white, transp=0, size=size.tiny)

barcolor(barbuy ? color.green : na)
barcolor(barsell ? color.red : na)

//Trailing stop loss
price_stop=0.0

if (strategy.position_size > 0)
    stopValue = close * (1 - targetPrice)
    price_stop:=max(stopValue, price_stop[1])
else
    price_stop:=0

if (strategy.position_size > 0)
    strategy.exit(id="stoplong", stop=price_stop)



if (strategy.position_size < 0)
    stopValue = close * (1 + targetPrice)
    price_stop:=max(stopValue, price_stop[1])
else
    price_stop:=0

if (strategy.position_size < 0)
    strategy.exit(id="stopshort", stop=price_stop)

I expected it to trail the stoploss in the trending direction

Answer 1

As you are new to Pine and you work with an outdated version of Pine (v4) then I assume you got this code from somewhere.

You need to spend some time understanding how Pine works.

For this specific issue, you should know that Pine executes your code on every candle, resetting every variable at the start of those calculations. If you want to retain any "older" value of some calculations, you have to use a variable that was declared with the var keyword as that indicates to Pine it should NOT reset the variable's value on each calculation.

Your trailing stop loss variables (and therefore the calculations) get reset on every calculation while a trailing SL should "remember" previous values.

Also you use the condition if (strategy.position_size > 0) for both updating the SL variable, and for Exit, which probably exists immediately.