Stationary Filtered Standing Wave with 2 filters

//@version=5
indicator("Stationary Filtered Standing Wave", overlay=false)

inp = input(close)

// User-defined parameters
len = input.int(title="Length", defval=50)
freq = input.float(title="Frequency", defval=1.0)

// Calculate standing wave values
wave = math.sin(2 * math.pi * freq * bar_index / len)

// Apply a stationary filter to smooth the wave and add close price
filterLen = 5
filterCoeff = 1.0 / filterLen
filteredWave = filterCoeff * (wave + wave[1] + wave[2] + wave[3] + wave[4] + inp)

// Apply another filter using time cycles
timeCycleLen = input.int(title="Time Cycle Length", defval=10)
timeCycleCoeff = 1.0 / timeCycleLen
timeCycle = 0.0
for i = 0 to timeCycleLen - 1
    timeCycle := timeCycle + filteredWave[i]
timeCycle := timeCycle / timeCycleLen
filteredWave2 = timeCycleCoeff * (filteredWave + filteredWave[1] + filteredWave[2] + filteredWave[3] + filteredWave[4] - timeCycle * 5)

// Apply a third filter enforcing symmetry of trigo functions from unit circle
symFilterLen = 3
symFilterCoeff = 1.0 / symFilterLen
symFilteredWave = symFilterCoeff * (filteredWave2 + filteredWave2[1] - filteredWave2[2])

// Plot the results
plot(symFilteredWave, color=color.blue, linewidth=2)