[RS]Linear Regression Bands V0

study(title="[RS]Linear Regression Bands V0", shorttitle="[RS]LRB.V0", overlay=true)
tf1 = input(0.125)
smooth = input(4)
prehh1 = nz(hh1[1], high)
prell1 = nz(ll1[1], low)

hh1 = close >= prehh1 ? high : prehh1 - sma(abs(change(high, 1)*tf1), smooth)
ll1 = close <= prell1 ? low : prell1 + sma(abs(change(low, 1)*tf1), smooth)
midline = avg(hh1, ll1)
plot(midline, style=cross, color=black, linewidth=1)
ph1 = plot(hh1, style=line, color=black, linewidth=1)
pl1 = plot(ll1, style=line, color=black, linewidth=1)