Session Highs and Lows Indicator (SMC Sessions, DST-safe)

// TradingView Pine Script V5 Indicator to mark the latest important levels
// This Pine Script™ code is subject to the terms of the Mozilla Public License 2.0 at https://mozilla.org/MPL/2.0/
// © tc3oliver

//@version=5
indicator("Session Highs and Lows Indicator (SMC Sessions, DST-safe)", overlay=true)

// Session 判斷在日線以上沒有意義（一根 K 涵蓋整天），會靜默畫出錯誤的線
if not timeframe.isintraday and barstate.islast
    runtime.error("This indicator requires an intraday timeframe (< 1D).")

// ======== 顯示開關 ========
showLondon       = input.bool(true, "Show London High/Low")
showNewYork      = input.bool(true, "Show New York High/Low")
showAsia         = input.bool(true, "Show Asia High/Low")
showNewYorkClose = input.bool(true, "Show New York Close High/Low")

// ======== 線條樣式設定 ========
londonColor   = input.color(color.new(#47abfd, 70), "London Line Color")
londonWidth   = input.int(1, "London Line Width", minval=1, maxval=5)

newYorkColor  = input.color(color.new(#ff6565, 70), "New York Line Color")
newYorkWidth  = input.int(1, "New York Line Width", minval=1, maxval=5)

nyCloseColor  = input.color(color.new(#ff9f43, 70), "NY Close Line Color")
nyCloseWidth  = input.int(1, "NY Close Line Width", minval=1, maxval=5)

asiaColor     = input.color(color.new(#75ff79, 70), "Asia Line Color")
asiaWidth     = input.int(1, "Asia Line Width", minval=1, maxval=5)


// --- SMC/ICT Sessions in New York time (DST-safe via America/New_York) ---
asianRangeSession = input.session("2000-0000", "Asian Range [NY time]")
londonSession     = input.session("0300-0500", "London Open [NY time]")
newYorkSession    = input.session("0830-1100", "New York AM [NY time]")
nyCloseSession    = input.session("1000-1200", "London Close Killzone (NY time)")

// 是否在各時段內（以 New York 時區判斷，DST 自動處理）
inAsiaSession         = not na(time("", asianRangeSession, "America/New_York"))
inLondonSession       = not na(time("", londonSession,     "America/New_York"))
inNewYorkSession      = not na(time("", newYorkSession,    "America/New_York"))
inNewYorkCloseSession = not na(time("", nyCloseSession,    "America/New_York"))

// Session 切換判斷（用 nz 防第一根 na）
isLondonSessionStart        =  inLondonSession and not nz(inLondonSession[1], false)
isLondonSessionEnd          = not inLondonSession and     nz(inLondonSession[1], false)

isNewYorkSessionStart       =  inNewYorkSession and not nz(inNewYorkSession[1], false)
isNewYorkSessionEnd         = not inNewYorkSession and     nz(inNewYorkSession[1], false)

isAsiaSessionStart          =  inAsiaSession and not nz(inAsiaSession[1], false)
isAsiaSessionEnd            = not inAsiaSession and     nz(inAsiaSession[1], false)

isNewYorkCloseSessionStart  =  inNewYorkCloseSession and not nz(inNewYorkCloseSession[1], false)
isNewYorkCloseSessionEnd    = not inNewYorkCloseSession and     nz(inNewYorkCloseSession[1], false)


// ======== 初始化變數 ========
var float londonHigh = na
var float londonLow = na
var int londonHighBar = na
var int londonLowBar = na
var int londonStartBar = na

var float newYorkHigh = na
var float newYorkLow = na
var int newYorkHighBar = na
var int newYorkLowBar = na
var int newYorkStartBar = na

var float asiaHigh = na
var float asiaLow = na
var int asiaHighBar = na
var int asiaLowBar = na
var int asiaStartBar = na

var float newYorkCloseHigh = na
var float newYorkCloseLow = na
var int newYorkCloseHighBar = na
var int newYorkCloseLowBar = na
var int newYorkCloseStartBar = na

var label londonHighLabel = na
var label londonLowLabel = na
var line londonHighLine = na
var line londonLowLine = na

var label newYorkHighLabel = na
var label newYorkLowLabel = na
var line newYorkHighLine = na
var line newYorkLowLine = na

var label asiaHighLabel = na
var label asiaLowLabel = na
var line asiaHighLine = na
var line asiaLowLine = na

var label newYorkCloseHighLabel = na
var label newYorkCloseLowLabel = na
var line newYorkCloseHighLine = na
var line newYorkCloseLowLine = na

// ======== 更新倫敦 ========
if isLondonSessionStart
    londonHigh := high
    londonLow := low
    londonHighBar := bar_index
    londonLowBar := bar_index
    londonStartBar := bar_index
else if inLondonSession
    if high > londonHigh
        londonHigh := high
        londonHighBar := bar_index
    if low < londonLow
        londonLow := low
        londonLowBar := bar_index
else if isLondonSessionEnd and showLondon
    label.delete(londonHighLabel)
    label.delete(londonLowLabel)
    line.delete(londonHighLine)
    line.delete(londonLowLine)
    londonHighLabel := label.new(londonHighBar, londonHigh, "London Killzone High", yloc=yloc.abovebar, color=londonColor, textcolor=color.white, style=label.style_label_down, size=size.small)
    londonLowLabel  := label.new(londonLowBar,  londonLow,  "London Killzone Low",  yloc=yloc.belowbar, color=londonColor, textcolor=color.white, style=label.style_label_up,   size=size.small)
    londonHighLine := line.new(londonStartBar, londonHigh, bar_index, londonHigh, xloc.bar_index, extend=extend.right, color=londonColor, width=londonWidth, style=line.style_dashed)
    londonLowLine := line.new(londonStartBar, londonLow, bar_index, londonLow, xloc.bar_index, extend=extend.right, color=londonColor, width=londonWidth, style=line.style_dashed)

// ======== 更新紐約 ========
if isNewYorkSessionStart
    newYorkHigh := high
    newYorkLow := low
    newYorkHighBar := bar_index
    newYorkLowBar := bar_index
    newYorkStartBar := bar_index
else if inNewYorkSession
    if high > newYorkHigh
        newYorkHigh := high
        newYorkHighBar := bar_index
    if low < newYorkLow
        newYorkLow := low
        newYorkLowBar := bar_index
else if isNewYorkSessionEnd and showNewYork
    label.delete(newYorkHighLabel)
    label.delete(newYorkLowLabel)
    line.delete(newYorkHighLine)
    line.delete(newYorkLowLine)
    newYorkHighLabel := label.new(newYorkHighBar, newYorkHigh, "New York AM Killzone High", yloc=yloc.abovebar, color=newYorkColor, textcolor=color.white, style=label.style_label_down, size=size.small)
    newYorkLowLabel  := label.new(newYorkLowBar,  newYorkLow,  "New York AM Killzone Low",  yloc=yloc.belowbar, color=newYorkColor, textcolor=color.white, style=label.style_label_up,   size=size.small)
    newYorkHighLine := line.new(newYorkStartBar, newYorkHigh, bar_index, newYorkHigh, xloc.bar_index, extend=extend.right, color=newYorkColor, width=newYorkWidth, style=line.style_dashed)
    newYorkLowLine := line.new(newYorkStartBar, newYorkLow, bar_index, newYorkLow, xloc.bar_index, extend=extend.right, color=newYorkColor, width=newYorkWidth, style=line.style_dashed)

// ======== 更新亞洲（Asian Range, NY 20:00–24:00） ========
if isAsiaSessionStart
    asiaHigh := high
    asiaLow := low
    asiaHighBar := bar_index
    asiaLowBar := bar_index
    asiaStartBar := bar_index
else if inAsiaSession
    if high > asiaHigh
        asiaHigh := high
        asiaHighBar := bar_index
    if low < asiaLow
        asiaLow := low
        asiaLowBar := bar_index
else if isAsiaSessionEnd and showAsia
    label.delete(asiaHighLabel)
    label.delete(asiaLowLabel)
    line.delete(asiaHighLine)
    line.delete(asiaLowLine)
    asiaHighLabel := label.new(asiaHighBar, asiaHigh, "Asian Range High", yloc=yloc.abovebar, color=asiaColor, textcolor=color.white, style=label.style_label_down, size=size.small)
    asiaLowLabel  := label.new(asiaLowBar,  asiaLow,  "Asian Range Low",  yloc=yloc.belowbar, color=asiaColor, textcolor=color.white, style=label.style_label_up,   size=size.small)
    asiaHighLine := line.new(asiaStartBar, asiaHigh, bar_index, asiaHigh, xloc.bar_index, extend=extend.right, color=asiaColor, width=asiaWidth, style=line.style_dashed)
    asiaLowLine := line.new(asiaStartBar, asiaLow, bar_index, asiaLow, xloc.bar_index, extend=extend.right, color=asiaColor, width=asiaWidth, style=line.style_dashed)

// ======== 更新紐約收盤 ========
if isNewYorkCloseSessionStart
    newYorkCloseHigh := high
    newYorkCloseLow := low
    newYorkCloseHighBar := bar_index
    newYorkCloseLowBar := bar_index
    newYorkCloseStartBar := bar_index
else if inNewYorkCloseSession
    if high > newYorkCloseHigh
        newYorkCloseHigh := high
        newYorkCloseHighBar := bar_index
    if low < newYorkCloseLow
        newYorkCloseLow := low
        newYorkCloseLowBar := bar_index
else if isNewYorkCloseSessionEnd and showNewYorkClose
    label.delete(newYorkCloseHighLabel)
    label.delete(newYorkCloseLowLabel)
    line.delete(newYorkCloseHighLine)
    line.delete(newYorkCloseLowLine)
    newYorkCloseHighLabel := label.new(newYorkCloseHighBar, newYorkCloseHigh, "London Close Killzone High", yloc=yloc.abovebar, color=nyCloseColor, textcolor=color.white, style=label.style_label_down, size=size.small)
    newYorkCloseLowLabel  := label.new(newYorkCloseLowBar,  newYorkCloseLow,  "London Close Killzone Low",  yloc=yloc.belowbar, color=nyCloseColor, textcolor=color.white, style=label.style_label_up,   size=size.small)
    newYorkCloseHighLine := line.new(newYorkCloseStartBar, newYorkCloseHigh, bar_index, newYorkCloseHigh, xloc.bar_index, extend=extend.right, color=nyCloseColor, width=nyCloseWidth, style=line.style_dashed)
    newYorkCloseLowLine := line.new(newYorkCloseStartBar, newYorkCloseLow, bar_index, newYorkCloseLow, xloc.bar_index, extend=extend.right, color=nyCloseColor, width=nyCloseWidth, style=line.style_dashed)