# indie:lang_version = 5
from indie import indicator, param, source, plot, color
from indie.algorithms import Bb


@indicator('BB', overlay_main_pane=True)  # Bollinger Bands
@param.int('length', default=20, min=1)
@param.source('src', default=source.CLOSE, title='Source')
@param.float('mult', default=2.0, min=0.001, max=50.0, title='StdDev')
@param.int('offset', default=0, min=-500, max=500)
@plot.line('lower', color=color.BLUE, title='Lower')
@plot.line(color=color.RED, title='Basis')
@plot.line('upper', color=color.BLUE, title='Upper')
@plot.fill('lower', 'upper', color=color.AQUA(0.05), title='Background')
def Main(self, length, src, mult, offset):
    (lower, middle, upper) = Bb.new(src, length, mult)
    return (
        plot.Line(lower[0], offset=offset),
        plot.Line(middle[0], offset=offset),
        plot.Line(upper[0], offset=offset),
        plot.Fill(offset=offset),
    )