Hann Window Amplitude Filter

//@version=5
indicator('Hann Window Amplitude Filter', overlay=false)


length = input(14, "Number of frequencies to Filter")
var shifts = input.int(0)
minBase = input.float(0.1, "Filter Minimum Base", step = .1)

int ArrayLen = 2 * length - 1
var Array = array.new_float(ArrayLen, 0),
pi = math.pi
c = 0.0
c := nz(c[1], 0) == ArrayLen - 1 ? 0 : nz(c[1], 0) + 1

h = (1 - math.cos(2 * pi * (c - 1) / ArrayLen)) / 2 + minBase

if bar_index <= ArrayLen
    array.insert(Array, 0, h)

else
    if shifts > 0
        for i = 0 to shifts - 1 by 1
            array.shift(Array)
            array.push(Array, minBase)
            shifts := shifts - 1
    else if shifts < 0
        for i = 0 to math.abs(shifts) - 1 by 1
            array.unshift(Array,minBase)
            shifts := shifts + 1


//
plot(h)
plot(array.get(Array, length), title='HW', color=color.new(#FA8258, 0))
plot(bar_index % ArrayLen, title='Bar Index % Array Len', color=color.new(#FA8258, 0), display=display.data_window)
plot(c, title='Counter', color=color.new(#FA8258, 0), display=display.data_window)
plot(array.get(Array, length - 1), title='MaxCoeff +', color=color.new(#FA8258, 0), display=display.data_window)
plot(array.get(Array, length), title='MaxCoeff -', color=color.new(#FA8258, 0), display=display.data_window)
plot(array.get(Array, math.floor(length / 2)), title='MinCoeff +', color=color.new(#FA8258, 0), display=display.data_window)
plot(array.get(Array, ArrayLen - math.floor(length / 2)), title='MinCoeff -', color=color.new(#FA8258, 0), display=display.data_window)
hline(0)
hline(1)