# indie:lang_version = 5
from indie import (
    indicator,
    param,
    plot,
    source,
    MainContext,
    color
)
from indie.algorithms import Sma

@indicator('Bollinger Bands Pro', overlay_main_pane=True)
@param.source('src', default=source.CLOSE)
@param.int('length', default=20, title='Perioden', min=1, max=100)
@param.float('mult', default=2.0, title='Multiplikator', min=0.5, max=3.0)
@plot.line('Basis', color=color.rgba(128, 128, 128, 1))
@plot.line('Oberes Band')
@plot.line('Unteres Band')
@plot.fill('Basis', 'Oberes Band', id='#fill_3')
@plot.fill('Basis', 'Unteres Band', id='#fill_4')
class Main(MainContext):
    def __init__(self, src, length, mult):
        self.src = src
        self.length = length
        self.mult = mult
        self.std_dev = self.new_mut_series_f()

    def calc(self):
        # SMA-Berechnung
        sma = Sma.new(self.src, self.length)
        basis = sma[0]

        # Standardabweichung
        sum_sq = 0.0
        for i in range(self.length):
            diff = self.src[i] - basis
            sum_sq += diff * diff
        stdev = (sum_sq / self.length) ** 0.5

        # Bänder berechnen
        upper = basis + self.mult * stdev
        lower = basis - self.mult * stdev

        # Farbwechsel-Logik
        upper_color = color.RED if self.high[0] >= upper else color.GRAY
        lower_color = color.GREEN if self.low[0] <= lower else color.GRAY

        return (
            basis,
            plot.Line(upper, color=upper_color),
            plot.Line(lower, color=lower_color),
            plot.Fill(color=color.BLACK(0.1)),
            plot.Fill(color=color.BLACK(0.1))
        )