//@version=6
indicator("Workshop 08 Reclaim Watch", overlay=true)
length = input.int(20, "Prior bars", minval=2)
reference = ta.lowest(low, length)[1]
probe = low < reference
returnInside = close > reference
signal = (bar_index >= length and probe and
    returnInside and barstate.isconfirmed)
plot(reference, "Prior low", color=color.gray)
plotshape(signal, "Reclaim", shape.triangleup,
    location.belowbar, color=color.blue, size=size.tiny)
alertcondition(signal, "Reclaim at close",
    "Prior low reclaimed on {{ticker}} {{interval}}")