//@version=5
indicator("Supertrend", overlay = true, timeframe = "", timeframe_gaps = true)

atrPeriod = input.int(10,    "ATR Length", minval = 1)
factor =    input.float(3.0, "Factor",     minval = 0.01, step = 0.01)

[supertrend, direction] = ta.supertrend(factor, atrPeriod)

supertrend := barstate.isfirst ? na : supertrend
upTrend =    plot(direction < 0 ? supertrend : na, "Up Trend",   color = color.green, style = plot.style_linebr)
downTrend =  plot(direction < 0 ? na : supertrend, "Down Trend", color = color.red,   style = plot.style_linebr)
bodyMiddle = plot(barstate.isfirst ? na : (open + close) / 2, "Body Middle",display = display.none)

fill(bodyMiddle, upTrend,   color.new(color.green, 90), fillgaps = false)
fill(bodyMiddle, downTrend, color.new(color.red,   90), fillgaps = false)

alertcondition(direction[1] > direction, title='Downtrend to Uptrend', message='The Supertrend value switched from Downtrend to Uptrend ')
alertcondition(direction[1] < direction, title='Uptrend to Downtrend', message='The Supertrend value switched from Uptrend to Downtrend')
alertcondition(direction[1] != direction, title='Trend Change', message='The Supertrend value switched from Uptrend to Downtrend or vice versa')