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 1

sawPeriod :: Signal
sawPeriod = \x -> 2*x-1

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

silence :: Signal
silence = \x -> 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))

-- rep :: Double -> Signal -> Signal
-- rep d signal = signal . (\x -> x - (fromIntegral $ floor x)) . (d*)

osc :: Signal -> ADSR -> Oscillator
osc signal a = \sem sec -> adsr a sec (signal . (\x -> x - (fromIntegral $ floor x)) . ((f sem)*))

linear :: (Seconds, Sample) -> (Seconds, Sample) -> (Signal -> Signal)
linear (s1, l1) (s2, l2) signal = \x ->
    if x >= s1 && x < s2 then (((l2-l1)*x + s2*l1 - s1*l2) / (s2-s1)) * (signal x)
        else signal x

adsr :: ADSR -> Seconds -> Signal -> Signal
adsr (attack, decay, sustain, release) duration signal =
    linear (0,0) (attack,1) $ linear (attack,1) (ad,sustain) $ linear (ad,sustain) (dr,sustain) $ linear (dr,sustain) (duration,0) $ signal
        where ad = attack + decay
              dr = duration - release

mix :: [SampledSignal] -> SampledSignal
mix ss
    | all null ss = []
    | otherwise = (sum [if null s then 0 else head s | s <- ss] / (fromIntegral $ length ss)) :
        mix [if null s then [] else tail s | s <- ss]

{-WETT-}

-- you can add new oscillators here
piano :: Oscillator
piano = osc sawPeriod (0.01, 0.1, 0.7, 0.2)

coolInstrument :: Oscillator
coolInstrument = osc (\x -> (sinPeriod x)
    + (0.8 * sinPeriod (2*x))
    + (0.6*sinPeriod 3*x)
    + (0.5*sinPeriod 4*x)
    + (0.2*sinPeriod 5*x)
    + (0.3*sinPeriod 6*x))
    (0.1, 0.2, 0.9, 0.4)

lead :: Oscillator
lead = osc sqwPeriod (0.01, 0.2, 0.3, 0.1)

bass :: Oscillator
bass = osc sinPeriod (0.001, 0.2, 0.9, 0.1)

-- 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 [coolInstrument, bass]
    audioTracks = zipWith playNotes instrs tracks
    audioNoEffects = mixTracks audioTracks [0.8, 0.7]
    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 [clip 0.9, addGain 4] 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.
    -- audio = applyEffectToInterval (2, 6) audioNoEffects distortion
{-TTEW-}