Previous Day High-Low (PDHL)

// This Pine Script® code is subject to the terms of the Mozilla Public License 2.0 at https://mozilla.org/MPL/2.0/
// © realanthonyc https://www.tradingview.com/u/realanthonyc

//@version=6
// --------------------------------------------------------------------
//  Previous Day High-Low (PDHL)
//  On Github: https://github.com/realanthonyc/PDHL
//  v1.1.0
// --------------------------------------------------------------------
indicator("Previous Day High-Low (PDHL)", shorttitle = "PDHL", format = format.price, overlay = true, precision = 2, max_lines_count = 450)

// === Inputs ===
string sessionInput = input.session("0930-1600", "Trading Session", tooltip = "Only prices within this time window are recorded. Use 0930-1600 for US Stocks or 0000-0000 for Crypto.")
int midHour = input.int(12, "Initial Position Hour", minval = 0, maxval = 23, tooltip = "The X-axis position before this hour will be fixed here.")
string timeZone = syminfo.timezone

// === Colors ===
color colorCore = color.rgb(235, 143, 5)
color colorExt = color.new(color.yellow, 0)

// === Fetch Last Trading Day's Data ===
// Referencing high[1] on Daily timeframe ensures we get the most recently closed daily bar.
float pdhRaw = request.security(syminfo.tickerid, "D", high[1], lookahead = barmerge.lookahead_on)
float pdlRaw = request.security(syminfo.tickerid, "D", low[1], lookahead = barmerge.lookahead_on)

// === Session & Price Tracking ===
bool inSession = not na(time(timeframe.period, sessionInput, timeZone))
bool isNewDay = ta.change(time("D", timeZone)) != 0
bool isSessionStart = inSession and (not inSession[1] or isNewDay)

var float stablePrevHigh = na
var float stablePrevLow = na
var float currentSessionHigh = na
var float currentSessionLow = na

// Update Previous Day values and reset Current Session values at the start of a new session
if isSessionStart
    stablePrevHigh := pdhRaw
    stablePrevLow := pdlRaw
    currentSessionHigh := high
    currentSessionLow := low
else if inSession
    currentSessionHigh := math.max(nz(currentSessionHigh, high), high)
    currentSessionLow := math.min(nz(currentSessionLow, low), low)

// === X-Axis Calculation Logic ===
int endHourParsed = int(str.tonumber(str.substring(sessionInput, 5, 7)))
int endMinParsed = int(str.tonumber(str.substring(sessionInput, 7, 9)))
bool isFullDay = sessionInput == "0000-0000"
int finalEndHour = isFullDay and endHourParsed == 0 ? 23 : endHourParsed
int finalEndMin = isFullDay and endHourParsed == 0 ? 59 : endMinParsed

get_x_pos(t) =>
    // Session end for the bar's day
    int sessionEndTs = timestamp(timeZone, year(t, timeZone), month(t, timeZone), dayofmonth(t, timeZone), finalEndHour, finalEndMin)
    int midTs = timestamp(timeZone, year(t, timeZone), month(t, timeZone), dayofmonth(t, timeZone), midHour, 0)
    
    int xPos = sessionEndTs
    
    bool isToday = year(t, timeZone) == year(timenow, timeZone) and month(t, timeZone) == month(timenow, timeZone) and dayofmonth(t, timeZone) == dayofmonth(timenow, timeZone)
    
    if isToday
        if t < midTs
            xPos := midTs
        else
            // Dynamic push forward by 1 hour, capped at session end
            xPos := math.min(t + 3600000, sessionEndTs)
    else
        // For historical days: fix at the session end of that day
        xPos := sessionEndTs
    
    xPos

// === Drawing Logic ===
var line liveCore = na
var line liveTop = na
var line liveBot = na

if inSession and not na(stablePrevHigh) and not na(stablePrevLow)
    int targetX = get_x_pos(time)
    
    if isSessionStart
        // Create new lines for the current session
        // When lines exceed max_lines_count (450), oldest lines are auto-deleted by Pine Script.
        liveCore := line.new(targetX, stablePrevLow, targetX, stablePrevHigh, xloc = xloc.bar_time, color = colorCore, width = 2)
        liveTop := line.new(targetX, stablePrevHigh, targetX, stablePrevHigh, xloc = xloc.bar_time, color = colorExt, width = 2)
        liveBot := line.new(targetX, stablePrevLow, targetX, stablePrevLow, xloc = xloc.bar_time, color = colorExt, width = 2)
    else if not na(liveCore)
        // Update lines dynamically during the session
        line.set_x1(liveCore, targetX)
        line.set_y1(liveCore, stablePrevLow)
        line.set_x2(liveCore, targetX)
        line.set_y2(liveCore, stablePrevHigh)
        
        // Yellow Extensions
        if not na(currentSessionHigh) and currentSessionHigh > stablePrevHigh
            line.set_xy1(liveTop, targetX, stablePrevHigh)
            line.set_xy2(liveTop, targetX, currentSessionHigh)
        else
            line.set_xy1(liveTop, na, na)
            line.set_xy2(liveTop, na, na)
           
        if not na(currentSessionLow) and currentSessionLow < stablePrevLow
            line.set_xy1(liveBot, targetX, stablePrevLow)
            line.set_xy2(liveBot, targetX, currentSessionLow)
        else
            line.set_xy1(liveBot, na, na)
            line.set_xy2(liveBot, na, na)