module Exercise06 where

import Data.List

import Effects
import Types

sinPeriod :: Signal
sinPeriod = sin . (2*pi*)

sqwPeriod :: Signal
sqwPeriod = \x -> (if x < 0.5 then -1 else if x > 0.5 then 1 else 0)

sawPeriod :: Signal
sawPeriod = (+) (-1) . (*2)

triPeriod :: Signal
triPeriod = \x -> (if x < 0.5 then x*4-1 else x*(-4)+3)

custPeriod :: Signal
custPeriod = \x -> ((sawPeriod x + sinPeriod x)/2 + 0.2)

silence :: Signal
silence = \_ -> 0

-- NOTE: the formula is taken from https://pages.mtu.edu/~suits/NoteFreqCalcs.html
f :: Semitone -> Hz
f n = 440.0 * (2 ** (fromInteger n / 12.0))

osc :: Signal -> ADSR -> Oscillator
osc sig a = res
  where 
    res :: Oscillator
    res sem dur = adsr a dur sg
      where 
        frq = f sem
        sg = \x -> sig (x*frq - fromIntegral(floor(x*frq)))  
     

adsr :: ADSR -> Seconds -> Signal -> Signal
adsr (a,d,s,r) dur sig = res
  where 
   res :: Signal
   res x 
     | x < a = (x*(1/a)) * (sig x)
     | x < a+d = ((x-a)*((s-1)/d) + 1) * (sig x)
     | x < (dur-r) = s * (sig x)
     | otherwise = ((x-dur+r) * ((-s)/r) + s) * (sig x)


vadd :: Num a => [a] -> [a] -> [a]
vadd xs [] = xs
vadd [] xs = xs
vadd (x:xs) (y:ys) = (x+y):(vadd xs ys)

mixAux :: [SampledSignal] -> SampledSignal
mixAux [] = []
mixAux [x] = x 
mixAux (x:y:xs) = mixAux ((vadd x y):xs) 


mix :: [SampledSignal] -> SampledSignal
mix xs = let s = fromIntegral (length xs) in mixAux (map (map (/s)) xs) 

{-WETT-}

-- you can add new oscillators here
piano :: Oscillator
piano = osc sawPeriod (0.1, 0.1, 0.7, 0.2)

lead :: Oscillator
lead = osc sqwPeriod (0.01, 0.02, 0.5, 0.1)

bass :: Oscillator
bass = osc sinPeriod (0.001, 0.02, 0.9, 0.1)

violin :: Oscillator
violin = osc sawPeriod (0.1, 0.01, 0.9, 0.03)

-- you can add more effects here



-- mix the signals with some volume
mixTracks :: [SampledSignal] -> [Double] -> SampledSignal
mixTracks trks vols = mix $ zipWith (\trk vol -> map (* vol) trk) trks vols

-- here we mix it all together and apply the effects
notesToSignal :: (Oscillator -> [Note] -> SampledSignal) -> [[Note]] -> SampledSignal
notesToSignal playNotes tracks = audio
  where
    -- specify the instruments of each track
    -- try the following instruments with the mario.mid file
    instrs = cycle [violin, lead]
    audioTracks = zipWith playNotes instrs tracks
    audioNoEffects = mixTracks audioTracks [0.2, 0.8]
    --audio = audioNoEffects
    -- To add effects, replace the line above by the line at the end of this comment and change the list off effects to your own effects.
    -- Note that the effects are applied from right to left, ie. the rightmost effect is applied first.
    --audio = addEffects [delay 0.03] audioNoEffects

    -- If you want to apply an effect only to parts of the signal, you can use the function applyEffectToInterval, as shown below.
    -- Thereby the first argument specifies the interval to which the effect should be applied in seconds.
    --audio1 = addEffects [distortion] audioNoEffects
    audio1 = applyEffectToInterval (16.5, 40) audioNoEffects $ echo 0.4
    audio2 = applyEffectToInterval (40, 56.7) audio1 $ crush
    --audio3 = applyEffectToInterval (40, 56.7) audio2 $ ampM triPeriod 50
    audio3 = applyEffectToInterval (40, 56.7) audio2 $ ffrq [2,4,8,16]
    audio4 = applyEffectToInterval (56.77, 79.8) audio3 $ echo 0.4
    audio5 = applyEffectToInterval (80, 113) audio4 $ ffrq [2,4,8,16]
    audio6 = applyEffectToInterval (0, 16) audio5 $ distortion
    audio7 = applyEffectToInterval (80, 113) audio6 $ ampM sinPeriod 10
    audio = applyEffectToInterval (75, 113) audio7 $ distortion 
{-TTEW-}
{-MCCOMMENT compile: stack run synth ./mid/best-song-you-ever-listened-to.mid best-song-you-ever-listened-to.wav
  - mid file src: https://bitmidi.com/never-gonna-give-you-up-3-mid
 I take no responsibility for hearing damage-}