Stella's Bollinger Squeeze

//@version=5
indicator("Stella's Bollinger Squeeze", shorttitle="BSQ", overlay=true)

// Bollinger Bands Squeeze Detector
// Identifies low volatility periods before potential breakouts

// Settings
length = input(20, "BB Length")
mult = input(2.0, "BB Multiplier")
kc_length = input(20, "KC Length")
kc_mult = input(1.5, "KC Multiplier")
squeeze_threshold = input(0.5, "Squeeze Threshold")

// Bollinger Bands
basis = ta.sma(close, length)
dev = mult * ta.stdev(close, length)
upper_bb = basis + dev
lower_bb = basis - dev

// Keltner Channel
kc_basis = ta.sma(close, kc_length)
range_val = ta.sma(ta.tr, kc_length)
upper_kc = kc_basis + kc_mult * range_val
lower_kc = kc_basis - kc_mult * range_val

// Squeeze detection
squeeze = (upper_bb < upper_kc) and (lower_bb > lower_kc)
no_squeeze = (upper_bb > upper_kc) and (lower_bb < lower_kc)

// Squeeze intensity
bb_width = (upper_bb - lower_bb) / basis
kc_width = (upper_kc - lower_kc) / kc_basis
squeeze_ratio = bb_width / kc_width

// Plot Bollinger Bands
plot(basis, "BB Basis", color=color.blue)
p1 = plot(upper_bb, "BB Upper", color=color.blue)
p2 = plot(lower_bb, "BB Lower", color=color.blue)
fill(p1, p2, color=color.new(color.blue, 90))

// Squeeze visual
bgcolor(squeeze ? color.new(color.yellow, 70) : na, title="Squeeze")
bgcolor(no_squeeze ? color.new(color.gray, 90) : na, title="No Squeeze")

// Breakout signals
breakout_up = ta.crossover(close, upper_bb) and not squeeze
breakout_down = ta.crossunder(close, lower_bb) and not squeeze

plotshape(breakout_up, "Breakout Up", shape.triangleup, location.belowbar, color.green, size=size.small)
plotshape(breakout_down, "Breakout Down", shape.triangledown, location.abovebar, color.red, size=size.small)

// Alerts
alertcondition(squeeze, "Squeeze Formed", "Bollinger Squeeze detected")
alertcondition(breakout_up, "Breakout Up", "Price broke above BB")
alertcondition(breakout_down, "Breakout Down", "Price broke below BB")
alertcondition(ta.crossover(squeeze_ratio, squeeze_threshold), "Squeeze Relaxing", "Volatility expanding")