//@version=6
indicator("Simplified two-session swings", overlay = true)
start = input.time(timestamp("01 Jan 2025 00:00 +0000"),
  "First eligible close time")
initialUp = input.bool(true, "Initial direction up")
if not timeframe.isdaily
    runtime.error("Use daily bars")
var bool up = initialUp
var int streak = 0
var float extreme = na
var float turn = na
turn := na
inside = high <= high[1] and low >= low[1]
outside = high > high[1] and low < low[1]
if barstate.isconfirmed and time_close >= start
    if na(extreme)
        extreme := up ? high : low
    else
        opposing = up ? low < low[1] : high > high[1]
        if inside
            streak := 0
        else
            streak := opposing ? streak + 1 : 0
        if streak >= 2
            turn := extreme
            up := not up
            extreme := up ? high : low
            streak := 0
        else
            extreme := up ? math.max(extreme, high) :
              math.min(extreme, low)
plot(turn, "Confirmed prior extreme", color.black,
  linewidth = 3, style = plot.style_circles)
bgcolor(outside and barstate.isconfirmed ?
  color.new(color.gray, 90) : na)