{-# language OverloadedStrings, DataKinds #-}
module MusicScroll.Providers.MusiXMatch (musiXMatchInstance) where

import Control.Category hiding ((.))
import Data.Maybe (catMaybes)
import Data.Text (Text, replace, toTitle)
import Network.HTTP.Req
import Text.HTML.TagSoup
import Text.HTML.TagSoup.Match (tagOpenAttrLit)
import Data.Traversable (mapAccumL)
-- import Data.Text.IO as T (readFile)

import MusicScroll.TrackInfo (TrackInfo(..))
import MusicScroll.Providers.Utils

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
  | tagOpenAttrLit "span" spanDiscr tag = (True, Nothing)
  | isTagCloseName "span" tag           = (False, Nothing)
  | otherwise                           = (onSpan, Nothing)
  where
    spanDiscr = ("class", "lyrics__content__ok")