Supertrend with Trend Change Arrows

//version=6
indicator("Supertrend with Trend Change Arrows", overlay = true, timeframe = "", timeframe_gaps = true)

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

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

// Plot 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)

// Fill Backgrounds
bodyMiddle = plot((open + close) / 2, "Body Middle", display = display.none)
fill(bodyMiddle, upTrend, title = "Uptrend background", color = color.new(color.green, 90), fillgaps = false)
fill(bodyMiddle, downTrend, title = "Downtrend background", color = color.new(color.red, 90), fillgaps = false)

// Detect Trend Changes
bullishFlip = direction < 0 and direction[1] >= 0 // Trend flipped from bearish to bullish
bearishFlip = direction >= 0 and direction[1] < 0 // Trend flipped from bullish to bearish

// Plot Arrows for Trend Changes
plotshape(bullishFlip, style=shape.triangleup, location=location.belowbar, color=color.green, size=size.small, text="▲", offset=0)
plotshape(bearishFlip, style=shape.triangledown, location=location.abovebar, color=color.red, size=size.small, text="▼", offset=0)

// Alert Conditions
alertcondition(bullishFlip, title='Downtrend to Uptrend', message='The Supertrend value switched from Downtrend to Uptrend')
alertcondition(bearishFlip, title='Uptrend to Downtrend', message='The Supertrend value switched from Uptrend to Downtrend')
alertcondition(bullishFlip or bearishFlip, title='Trend Change', message='The Supertrend value switched from Uptrend to Downtrend or vice versa')