Coppock WMA

study("Coppock WMA")
wmaLength = input(title="WMA Length", type=integer, defval=10)
longRoCLength = input(title="Long RoC Length", type=integer, defval=14)
shortRoCLength = input(title="Short RoC Length", type=integer, defval=11)
_crossoverMA = input(title="Crossover WMA Lenth", defval=5, minval=1)
_histogramMultiplier = input(title="Histogram Multiplier", defval=2, type=float)

_sourcec = close

_curve = wma(roc(_sourcec, longRoCLength) + roc(_sourcec, shortRoCLength), wmaLength)
_curveWMA = wma(_curve, _crossoverMA)

_h = (_curve - _curveWMA) * _histogramMultiplier

_curveWMAx = cross(_curve, _curveWMA) ? (_curve + _curveWMA) * 0.5 : na

mathcall = (abs(lowest(_curve,50)) + abs(highest(_curve,50))) * 0.3
highalert = highest(_curve,50) - mathcall
lowalert = lowest(_curve,50) + mathcall 

plot(highalert, color=blue)
plot(lowalert, color=red)
plot(_curve, color=gray, linewidth=2, title="Coppock Curve")
plot(_curveWMA, color=#CC9900, title="Moving Average")
plot(_curveWMAx, title="Crossover", color=white, style=cross, linewidth=3)