module Main where

import Control.Exception
import Control.Monad
import qualified Data.ByteString.Char8 as B8
import GHC.IO.Encoding (setLocaleEncoding)
import Lib
import Network.HTTP.Client
import Network.HTTP.Simple
import Network.URI
import System.Directory
import System.Exit
import System.FilePath
import System.IO
import System.Signal

main :: IO ()
main = do
  setLocaleEncoding utf8
  createDirectoryIfMissing False =<< workingDir
  join $ (writeFile <$> fileName) <*> pure ""
  installHandler sigINT sigIntHandler
  installHandler sigTERM sigIntHandler
  forever $ do
    end <- isEOF
    if end
      then sigIntHandler sigTERM
      else do
        line <- getLine
        dispatch line

dispatch :: String -> IO ()
dispatch ('T' : 'I' : 'T' : 'L' : 'E' : ':' : title) = writeToFile title 0
dispatch ('A' : 'R' : 'T' : 'I' : 'S' : 'T' : ':' : artist) = writeToFile artist 1
dispatch ('A' : 'L' : 'B' : 'U' : 'M' : ':' : album) = writeToFile album 2
dispatch ('C' : 'O' : 'V' : 'E' : 'R' : ':' : cover) = handleCover cover
dispatch _ = return ()

writeToFile :: String -> Int -> IO ()
writeToFile text position = do
  contents <- lines <$> (readFile =<< fileName)
  let newContent = unlines $ take position contents ++ [text] ++ drop (position + 1) contents
  bracketOnError
    (openTempFile "." "temp")
    ( \(tempName, tempHandle) -> do
        hClose tempHandle
        removeFile tempName
    )
    ( \(tempName, tempHandle) -> do
        hPutStr tempHandle newContent
        hClose tempHandle
        renameFile tempName =<< fileName
    )

handleCover :: String -> IO ()
handleCover url = do
  contents <- lines <$> (readFile =<< fileName)
  if length contents > 3 && (contents !! 3) /= url && url /= ""
    then do
      writeToFile url 3
      request <- parseRequest url
      let coverFileName = Prelude.last . pathSegments . getUri $ request
      join $ B8.writeFile <$> coverName <*> (getResponseBody <$> httpBS request)
    else writeToFile url 3

-- B8.writeFile coverName $ getResponseBody resp

fileName :: IO FilePath
fileName = (</> "wnpClient.txt") <$> workingDir

coverName :: IO FilePath
coverName = (</> "cover.jpg") <$> workingDir

workingDir :: IO FilePath
workingDir = (</> ".wnpClient") <$> getHomeDirectory

sigIntHandler :: System.Signal.Handler
sigIntHandler _ = do
  join $ (writeFile <$> fileName) <*> pure ""
  hPutStrLn stderr ("Handle exit")
  exitSuccess