TrendLines with Alerts
// This source code is subject to the terms of the Mozilla Public License 2.0 at https://mozilla.org/MPL/2.0/
// © pune3tghai

//Originally posted by matsu_bitmex

//tried adding alerts on plots and cleared the chart for a cleaner view.
//Publishing the script in hope of getting it improved by someone else.

//Added strategy code for easier calculations

//Needs work on TP and SL part.

//P.S - THE ORIGINAL CODE IS MUCH BETTER BUT I have tried to be more usable and understandable.

//@version=4
strategy("TrendLines with Alerts", overlay=true)     //study("TrendLines with Alerts", overlay=true)
//update

length1 = input(20)
check = input(9)
//length2 = input(200)


u=0.0
u := u[1]

l=0.0
l := l[1]

y=0.0
y := y[1]

yl=0.0
yl := yl[1]

angle = 0.0
angle := angle[1]

anglel = 0.0
anglel := anglel[1]

if (highest(length1) == high[check] and highest(length1) == highest(length1)[check] and barssince(barstate.isfirst) > check)
    u := high[check]

    
if (lowest(length1) == low[check] and lowest(length1) == lowest(length1)[check] and barssince(barstate.isfirst) > check)
    l := low[check]
    

    
p = round(barssince(u == high[check]))

pl = round(barssince(l == low[check]))

if p == 0 and barssince(barstate.isfirst) > check
    y := high[abs(p[1]+1+check)]
    
if pl == 0 and barssince(barstate.isfirst) > check
    yl := low[abs(pl[1]+1+check)]    
    

if p == 0
    angle := (u-y)/p[1]

if pl == 0
    anglel := (l-yl)/pl[1]

uppertrend = u+ (p * angle)

lowertrend = l+ (pl * anglel)

extendup = if barssince(barstate.isfirst) > check
    uppertrend[check] + angle[check] * check*2

extenddown = if barssince(barstate.isfirst) > check
    lowertrend[check] + anglel[check] * check*2




//plot(l[offset]-u,color=red)
//plot(u[offset]-l,color = green )
plot(lowertrend, color = color.green, transp=30,offset = -check)
plot(extenddown, color = color.green, transp=100)
plot(uppertrend, color = color.red, transp=30, offset = -check)
plot(extendup, color = color.red, transp=100)
//plot(l[offset], color = red)

l1 = lowertrend
l2 = extenddown
u1 = uppertrend
u2 = extendup



l2sell = crossunder(high, l2)
u2buy = crossover(low, u2)
buy1 = (low<=lowertrend) and open>lowertrend and high>lowertrend and close>lowertrend
buy2 = (low<=extenddown) and open>extenddown and high>extenddown and close>extenddown
buy = buy1 or buy2 or u2buy
plotshape(series=buy, title="Buy", style=shape.triangleup, size=size.tiny, color=color.lime, location=location.belowbar)
sell1 = (high>=uppertrend) and open<uppertrend and low<uppertrend and close<uppertrend
sell2 = (high>=extendup) and open<extendup and low<extendup and close<extendup
sell = sell1 or sell2 or l2sell
plotshape(series=sell, title="Sell", style=shape.triangledown, size=size.tiny, color=color.red, location=location.abovebar)

longCond = buy
shortCond = sell

tp = input(0.2, title="Take Profit")

tpbuyval = valuewhen(buy, close, 1) + (tp/100)*(valuewhen(buy, close, 1))
tpsellval = valuewhen(sell, close, 1) - (tp/100)*(valuewhen(sell, close, 1))


sl = input(0.2, title="Stop Loss")
slbuyval = valuewhen(buy, close, 0) - (sl/100)*(valuewhen(buy, close, 0))
slsellval = valuewhen(sell, close, 0) + (sl/100)*(valuewhen(sell, close, 0))
// === STRATEGY ===
tradeType = input("BOTH", title="What trades should be taken : ", options=["LONG", "SHORT", "BOTH", "NONE"])

// stop loss
slPoints = input(defval=0, title="Initial Stop Loss Points (zero to disable)", minval=0)
tpPoints = input(defval=0, title="Initial Target Profit Points (zero for disable)", minval=0)

//>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>//

testStartYear = input(2019, "Backtest Start Year", minval=1980)
testStartMonth = input(1, "Backtest Start Month", minval=1, maxval=12)
testStartDay = input(1, "Backtest Start Day", minval=1, maxval=31)
testPeriodStart = timestamp(testStartYear, testStartMonth, testStartDay, 0, 0)

testStopYear = input(9999, "Backtest Stop Year", minval=1980)
testStopMonth = input(12, "Backtest Stop Month", minval=1, maxval=12)
testStopDay = input(31, "Backtest Stop Day", minval=1, maxval=31)
testPeriodStop = timestamp(testStopYear, testStopMonth, testStopDay, 0, 0)

testPeriod() =>
    time >= testPeriodStart and time <= testPeriodStop ? true : false

//<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<//

//
//set up exit parameters
TP = tpPoints > 0 ? tpPoints : na
SL = slPoints > 0 ? slPoints : na

// Make sure we are within the bar range, Set up entries and exit conditions
if testPeriod() and tradeType != "NONE"
    strategy.entry("long", strategy.long, when=longCond == true and tradeType != "SHORT")
    strategy.entry("short", strategy.short, when=shortCond == true and tradeType != "LONG")
    strategy.close("long", when=shortCond == true and tradeType == "LONG")
    strategy.close("short", when=longCond == true and tradeType == "SHORT")
    strategy.exit("XL", from_entry="long", profit=tpbuyval, loss=slbuyval)
    strategy.exit("XS", from_entry="short", profit=tpsellval, loss=slsellval)

// === /STRATEGY ===
//EOF


////ALERT SYNTEX
//alertcondition(longCond, title="Long", message="Killer Market")
//alertcondition(shortCond, title="Short", message="Poopy Market")