{-# language PatternSynonyms #-}
module MusicScroll.TrackSuplement
  ( tsTitle, tsArtist, tsKeepArtist, TrackSuplement() , trackSuplement
  , suplement, mergeSuplement, suplementOnlyArtist) where

import Data.Text
import Pipes (Pipe)
import qualified Pipes.Prelude as PP (map)

import MusicScroll.TrackInfo ( TrackInfo(..), TrackByPath(..)
                             , TrackIdentifier, pattern OnlyMissingArtist )


-- | Invariant, always a valid artist text.
data TrackSuplement = TrackSuplement
  { tsTitle :: Text
  , tsArtist :: Text
  , tsKeepArtist :: Bool }

trackSuplement :: Text -> Text -> Bool -> Maybe TrackSuplement
trackSuplement title artist keep
  | strip artist == artist = pure (TrackSuplement title artist keep)
  | otherwise = Nothing

suplement :: TrackSuplement -> TrackIdentifier -> TrackInfo
suplement supl = either byPath byInfo
  where
    byPath :: TrackByPath -> TrackInfo
    byPath path = TrackInfo { tTitle  = tsTitle supl
                            , tArtist = tsArtist supl
                            , tUrl    = tpPath path }

    byInfo :: TrackInfo -> TrackInfo
    byInfo info = info { tTitle = tsTitle supl, tArtist = tsArtist supl}

mergeSuplement :: Functor m => TrackSuplement -> Pipe TrackIdentifier TrackInfo m a
mergeSuplement = PP.map . suplement

suplementOnlyArtist :: TrackSuplement -> TrackIdentifier -> TrackIdentifier
suplementOnlyArtist supl (Left byPath@OnlyMissingArtist) =
  let trackinfo = TrackInfo { tTitle  = maybe mempty id (tpTitle byPath)
                            , tArtist = tsArtist supl
                            , tUrl    = tpPath byPath }
  in Right trackinfo
suplementOnlyArtist _ other = other