DJZS Session Tracker (PDT-Aligned)

//version=5
indicator("DJZS Session Tracker (PDT-Aligned)", overlay=true, max_lines_count=500)

// Extract current date/time
var int y = year(time)
var int mo = month(time)
var int d = dayofmonth(time)

// Convert local session times (PDT = UTC-7)
asia_start = timestamp("America/Los_Angeles", y, mo, d, 17, 0)
asia_end = timestamp("America/Los_Angeles", y, mo, d + 1, 2, 0)
london_start = timestamp("America/Los_Angeles", y, mo, d + 1, 0, 0)
london_end = timestamp("America/Los_Angeles", y, mo, d + 1, 9, 0)
ny_start = timestamp("America/Los_Angeles", y, mo, d + 1, 5, 0)
ny_end = timestamp("America/Los_Angeles", y, mo, d + 1, 14, 0)

in_session(start, end) =>
time >= start and time < end

asia = in_session(asia_start, asia_end)
london = in_session(london_start, london_end)
ny = in_session(ny_start, ny_end)

// Plot background for sessions
bgcolor(asia ? color.new(color.aqua, 85) : na)
bgcolor(london ? color.new(color.green, 85) : na)
bgcolor(ny ? color.new(color.orange, 85) : na)

// Track session highs/lows
var float asiaHigh = na
var float asiaLow = na
var float londonHigh = na
var float londonLow = na
var float nyHigh = na
var float nyLow = na

if asia
asiaHigh := na(asiaHigh) ? high : math.max(asiaHigh, high)
asiaLow := na(asiaLow) ? low : math.min(asiaLow, low)
else
asiaHigh := na
asiaLow := na

if london
londonHigh := na(londonHigh) ? high : math.max(londonHigh, high)
londonLow := na(londonLow) ? low : math.min(londonLow, low)
else
londonHigh := na
londonLow := na

if ny
nyHigh := na(nyHigh) ? high : math.max(nyHigh, high)
nyLow := na(nyLow) ? low : math.min(nyLow, low)
else
nyHigh := na
nyLow := na

// Plot session highs/lows
plot(asiaHigh, "Asia High", color=color.aqua, style=plot.style_linebr, linewidth=1)
plot(asiaLow, "Asia Low", color=color.aqua, style=plot.style_linebr, linewidth=1)
plot(londonHigh, "London High", color=color.green, style=plot.style_linebr, linewidth=1)
plot(londonLow, "London Low", color=color.green, style=plot.style_linebr, linewidth=1)
plot(nyHigh, "NY High", color=color.orange, style=plot.style_linebr, linewidth=1)
plot(nyLow, "NY Low", color=color.orange, style=plot.style_linebr, linewidth=1)