# indie:lang_version = 5
from indie import indicator, format, param, level, color, plot
from indie.algorithms import Sma


@indicator('DPO', format=format.PRICE)  # Detrended Price Oscillator
@param.int('length', default=21, min=1)
@param.bool('centered', default=False, title='Centered')
@level(0, line_color=color.GRAY, title='Zero')
@plot.line(color=color.GREEN, title='Detrended Price Oscillator')
def Main(self, length, centered):
    bars_back = length // 2 + 1
    ma = Sma.new(self.close, length)
    dpo = self.close[bars_back] - ma[0] if centered else self.close[0] - ma[bars_back]
    return plot.Line(dpo, offset=-bars_back if centered else 0)