Seykota Alt 15: Single Position

// This Pine Script® code is subject to the terms of the Mozilla Public License 2.0 at https://mozilla.org/MPL/2.0/
// © danieltuckerrust
// ALTERNATIVE 15: Single Position (No Pyramid)
// THEORY: Pyramiding overconcentrates risk; single positions are simpler and more robust.
// The baseline pyramids up to 4 units, risking 1% each. This concentrates exposure as trends
// extend, and late adds can blow up if the trend reverses. This alternative takes ONE entry
// with the FULL risk budget (e.g., 4% in a single position) and never adds. Simpler logic,
// no pyramid tracking, and exposure is front-loaded rather than accumulated.
// Trade-off: Simpler, lower peak exposure, but misses compounding benefit of pyramids.

//@version=6
strategy("Seykota Alt 15: Single Position v1.0",
     overlay=true,
     initial_capital=100000,
     commission_type=strategy.commission.percent, commission_value=0.005,
     slippage=2,
     default_qty_type=strategy.fixed, default_qty_value=0,
     pyramiding=1,  // CHANGED: No pyramiding
     max_bars_back=5000)

//================ Inputs
allowLong   = input.bool(true,  "Allow LONGs?")
allowShort  = input.bool(true,  "Allow SHORTs?")

entryLen    = input.int(55,     "Donchian ENTRY lookback",            minval=10)
exitLen     = input.int(10,     "Donchian EXIT lookback",             minval=5)
nLen        = input.int(20,     "N = ATR length",                     minval=5)
stopN       = input.float(2.0,  "Initial stop (in N)",                minval=0.5, step=0.25)

// CHANGED: Single position risk (no add-on parameters)
riskPct     = input.float(4.0,  "Risk % for FULL position",           minval=0.1, maxval=10, step=0.1)

useMarket   = input.bool(false, "Use market regime filter?")
marketSym   = input.symbol("SPY", "Market symbol for regime (if used)")
marketTF    = input.timeframe("D", "Regime timeframe (if used)")
marketLen   = input.int(200,    "Market MA length (if used)",         minval=50)

timeExitMode= input.string("None","Time exit", options=["None","Close","Roll"])
timeExitBars= input.int(60,     "Time exit bars (if used)",           minval=5)

minVol      = input.int(0,      "Min 20-bar avg volume (chart TF)",   minval=0)
showSignals = input.bool(true,  "Plot signals & stops?")
plotDon     = input.bool(true,  "Plot Donchian bands?")

// Date-range filter
fromDate = input.time(defval=timestamp("2022-01-01T00:00:00"), title="Backtest FROM (yyyy-mm-dd)", confirm=true)
toDate   = input.time(defval=timestamp("2099-12-31T23:59:59"), title="Backtest TO (yyyy-mm-dd)",   confirm=true)
flatAtFrom = input.bool(true, "Force FLAT at range start?")
isRangeStart = (time[1] < fromDate) and (time >= fromDate)
if flatAtFrom and isRangeStart and strategy.position_size != 0
    strategy.close_all(comment="Flat at FROM")

//================ Helpers (simplified - single position only)
sharesForPosition(_equity, _Nentry) =>
    riskDollars   = _equity * (riskPct/100.0)
    perShareRisk  = math.max(stopN * _Nentry, syminfo.mintick)
    math.max(1, math.floor(riskDollars / perShareRisk))

inRange = (time >= fromDate) and (time <= toDate)

//================ Core calcs
N        = ta.atr(nLen)
volMA    = ta.sma(volume, 20)
liqOK    = volMA >= minVol

// Donchian levels
donHi    = ta.highest(high, entryLen)
donLo    = ta.lowest(low,  entryLen)
donHiPrev= donHi[1]
donLoPrev= donLo[1]

exitHiPrev = ta.highest(high, exitLen)[1]
exitLoPrev = ta.lowest(low,  exitLen)[1]

// Market regime (optional)
mClose = request.security(marketSym, marketTF, close)
mMA    = request.security(marketSym, marketTF, ta.sma(close, marketLen))
longRegOK  = not useMarket or (mClose > mMA)
shortRegOK = not useMarket or (mClose < mMA)

//================ Signals
longBreak  = allowLong  and liqOK and longRegOK  and (close > donHiPrev)
shortBreak = allowShort and liqOK and shortRegOK and (close < donLoPrev)

//================ Position state (simplified - no pyramiding variables)
var float N_entry       = na
var int   barsInPos     = 0
var bool  wantReenterL  = false
var bool  wantReenterS  = false

inPos     = strategy.position_size != 0
inLong    = strategy.position_size > 0
inShort   = strategy.position_size < 0

if inPos
    barsInPos += 1
else
    barsInPos    := 0
    N_entry      := na
    wantReenterL := false
    wantReenterS := false

//================ Entries (SINGLE POSITION - no add-ons)
if inRange and not inPos and longBreak
    N_entry := N
    float sh = sharesForPosition(strategy.equity, N_entry)
    strategy.entry("L", strategy.long, qty=sh)

if inRange and not inPos and shortBreak
    N_entry := N
    float sh = sharesForPosition(strategy.equity, N_entry)
    strategy.entry("S", strategy.short, qty=sh)

// NO ADD-ON LOGIC - single entry only

//================ Exits
var float stopL = na
var float stopS = na

if inRange and inLong
    initStopL = strategy.position_avg_price - stopN * N_entry
    stopL     := math.max(initStopL, exitLoPrev)
    strategy.exit("L-EXIT", from_entry="L", stop=stopL)
else
    stopL := na

if inRange and inShort
    initStopS = strategy.position_avg_price + stopN * N_entry
    stopS     := math.min(initStopS, exitHiPrev)
    strategy.exit("S-EXIT", from_entry="S", stop=stopS)
else
    stopS := na

//================ Optional time exit
timeExitTrig = inRange and inPos and (timeExitMode != "None") and (barsInPos >= timeExitBars)

if timeExitTrig
    if inLong
        if timeExitMode == "Close"
            strategy.close("L", comment="Time Exit")
        else if timeExitMode == "Roll"
            wantReenterL := true
            strategy.close("L", comment="Time Exit (Roll)")
    if inShort
        if timeExitMode == "Close"
            strategy.close("S", comment="Time Exit")
        else if timeExitMode == "Roll"
            wantReenterS := true
            strategy.close("S", comment="Time Exit (Roll)")

// Re-enter after Roll
if inRange and not inPos and wantReenterL and longRegOK and (close > donHiPrev)
    N_entry := N
    float sh = sharesForPosition(strategy.equity, N_entry)
    strategy.entry("L", strategy.long, qty=sh)
    wantReenterL := false

if inRange and not inPos and wantReenterS and shortRegOK and (close < donLoPrev)
    N_entry := N
    float sh = sharesForPosition(strategy.equity, N_entry)
    strategy.entry("S", strategy.short, qty=sh)
    wantReenterS := false

//================ Plots
float dHiPlot = plotDon ? donHi : na
float dLoPlot = plotDon ? donLo : na
plot(dHiPlot, "Donchian High", color=color.new(color.blue, 40))
plot(dLoPlot, "Donchian Low",  color=color.new(color.blue, 40))

plotshape(showSignals and longBreak,  title="Long Entry",   style=shape.triangleup,   location=location.belowbar, size=size.normal, color=color.new(color.green, 0), text="SINGLE LONG")
plotshape(showSignals and shortBreak, title="Short Entry",  style=shape.triangledown, location=location.abovebar, size=size.normal, color=color.new(color.red,   0), text="SINGLE SHORT")

plot(showSignals and inLong  ? stopL : na, "Long Stop",  color=color.new(color.red,  0), style=plot.style_linebr, linewidth=2)
plot(showSignals and inShort ? stopS : na, "Short Stop", color=color.new(color.red,  0), style=plot.style_linebr, linewidth=2)

// Info table emphasizing single position
var table infoTable = table.new(position.top_right, 2, 5, border_width=1)
if barstate.islast and showSignals
    table.cell(infoTable, 0, 0, "Position Type:", text_color=color.white, bgcolor=color.gray)
    table.cell(infoTable, 1, 0, "SINGLE", text_color=color.white, bgcolor=color.blue)

    table.cell(infoTable, 0, 1, "Pyramiding:", text_color=color.white, bgcolor=color.gray)
    table.cell(infoTable, 1, 1, "NONE", text_color=color.white, bgcolor=color.blue)

    table.cell(infoTable, 0, 2, "Full Position Risk:", text_color=color.white, bgcolor=color.gray)
    table.cell(infoTable, 1, 2, str.tostring(riskPct) + "%", text_color=color.white, bgcolor=color.blue)

    table.cell(infoTable, 0, 3, "In Position:", text_color=color.white, bgcolor=color.gray)
    posStatus = inPos ? "YES" : "NO"
    posColor = inPos ? color.green : color.gray
    table.cell(infoTable, 1, 3, posStatus, text_color=color.white, bgcolor=posColor)

    table.cell(infoTable, 0, 4, "Bars Held:", text_color=color.white, bgcolor=color.gray)
    table.cell(infoTable, 1, 4, str.tostring(barsInPos), text_color=color.white, bgcolor=color.gray)

// Comparison note
var label compLabel = na
if barstate.islast and showSignals
    noteText = "Single Position\nvs\nBaseline 4×1% Pyramid\n\nSimpler | Less Exposure\nBut No Compounding"
    label.delete(compLabel)
    compLabel := label.new(bar_index - 50, low, noteText, style=label.style_label_up, color=color.new(color.blue, 80), textcolor=color.white, size=size.small)