{-# LANGUAGE DataKinds #-}
{-# LANGUAGE OverloadedStrings #-}

module MusicScroll.Providers.MusiXMatch (musiXMatchInstance) where

import Control.Category hiding ((.))
import Data.Maybe (catMaybes)
import qualified Data.Set as Set
import Data.Text (Text, replace, toTitle)
import Data.Traversable (mapAccumL)
-- import Data.Text.IO as T (readFile)

import MusicScroll.Providers.Utils
import MusicScroll.TrackInfo (TrackInfo (..))
import Network.HTTP.Req
import Text.HTML.TagSoup
import Text.HTML.TagSoup.Match (anyAttr, tagOpenLit)

musiXMatchInstance :: Provider
musiXMatchInstance =
  Provider
    { toUrl = toUrl',
      extractLyricsFromPage = pipeline
    }

toUrl' :: TrackInfo -> Url 'Https
toUrl' track =
  let base :: Url 'Https
      base = https "www.musixmatch.com"

      quotedArtist = normalize (tArtist track)
      quotedSong = normalize (tTitle track)
   in base /: "lyrics" /: quotedArtist /: quotedSong

normalize :: Text -> Text
normalize = let noSpaces = replace " " "-" in noSpaces . toTitle

-- exampleTrack = TrackInfo "hey jude" "the beatles" "/home"

-- testOnFile fp =
--   do contents <- T.readFile fp
--      return (pipeline contents)

pipeline :: Text -> Lyrics
pipeline =
  parseTags >>> mapAccumL discriminate False
    >>> snd
    >>> catMaybes
    >>> innerText
    >>> Lyrics

--
discriminate :: Bool -> Tag Text -> (Bool, Maybe (Tag Text))
discriminate onSpan@True tag | isTagText tag = (onSpan, pure tag)
discriminate onSpan tag
  | tagOpenLit "span" goodClasses tag = (True, Nothing)
  | isTagCloseName "span" tag = (False, Nothing)
  | otherwise = (onSpan, Nothing)
  where
    goodClasses = anyAttr (\attr -> Set.member attr spanDiscr)
    spanDiscr =
      Set.fromList
        [ ("class", "lyrics__content__ok"),
          ("class", "lyrics__content__warning")
        ]