Piecewise Continuous Wav

module Pattern where
import Data.Int
import Data.WAVE
import System.Process

sampleRate = 44100
bitrate = 32

genWaveFormCycle p fs = samples
    where
        doubleList = fs <*> map (* (2 * p * pi / (fromIntegral sampleRate))) [0.0 .. (fromIntegral sampleRate ) / p]
        samples = map doubleToSample doubleList

genWaveForm :: [WAVESample]  -- | One cycle of the wave
            -> Int           -- | duration in seconds
            -> [WAVESample]

genWaveForm wavecycle duration = concat $ replicate n wavecycle
    where
        n = duration * sampleRate `div` (length wavecycle)

genWaveFile xs = WAVE header xs
    where header = WAVEHeader 1 sampleRate bitrate (Just $ length $ concat xs)

wobbleFuncs = map (\x y -> 0.5 * sin (x * y) ) [1.0, 1.1 .. 3]
genWobbleWave p d = genWaveForm (genWaveFormCycle p (wobbleFuncs ++ (reverse wobbleFuncs))) d
wobbleWave = genWaveFile $ concat  $ replicate 4  [ genWobbleWave 55 3 , genWobbleWave 97.99886 1]

main :: IO ()
main =
    do
        putWAVEFile "out.wav" wobbleWave
        pid <- runCommand "aplay -q out.wav"
        -- waitForProcess pid
        return ()