module DiffOutput where

import Source
import Term
import Control.Comonad.Cofree
import qualified Data.Text as T
import Diff
import Syntax
import Range
import qualified Data.ByteString.Char8 as B1
import qualified Data.Text.ICU.Detect as Detect
import qualified Data.Text.ICU.Convert as Convert
import Split
import Unified
import System.Directory
import System.FilePath
import qualified System.IO as IO
import qualified Data.Text.Lazy.IO as TextIO
import qualified PatchOutput
import Interpreter
import qualified Parsers as P

-- | The available types of diff rendering.
data Format = Unified | Split | Patch

data DiffArguments = DiffArguments { format :: Format, output :: Maybe FilePath, outputPath :: FilePath }

parserForFilepath :: FilePath -> P.Parser
parserForFilepath = P.parserForType . T.pack . takeExtension

-- | Replace every string leaf with leaves of the words in the string.
breakDownLeavesByWord :: Source Char -> Term T.Text Info -> Term T.Text Info
breakDownLeavesByWord source = cata replaceIn
  where
    replaceIn info@(Info range categories) (Leaf _) | ranges <- rangesAndWordsInSource range, length ranges > 1 = info :< (Indexed $ makeLeaf categories <$> ranges)
    replaceIn info syntax = info :< syntax
    rangesAndWordsInSource range = rangesAndWordsFrom (start range) (Source.toList $ slice range source)
    makeLeaf categories (range, substring) = Info range categories :< Leaf (T.pack substring)

-- | Transcode a file to a unicode source.
transcode :: B1.ByteString -> IO (Source Char)
transcode text = fromText <$> do
  match <- Detect.detectCharset text
  converter <- Convert.open match Nothing
  return $ Convert.toUnicode converter text

readAndTranscodeFile :: FilePath -> IO (Source Char)
readAndTranscodeFile path = do
  text <- B1.readFile path
  transcode text

printDiff :: DiffArguments -> (SourceBlob, SourceBlob) -> (Term T.Text Info, Term T.Text Info) -> IO ()
printDiff arguments (aSource, bSource) (aTerm, bTerm) = case format arguments of
  Unified -> do
    rendered <- unified diff (aSource, bSource)
    B1.putStr rendered
  Split -> do
    rendered <- split diff (aSource, bSource)
    case output arguments of
      Just path -> do
        isDir <- doesDirectoryExist path
        let outputPath = if isDir
                         then path </> (takeFileName outputPath -<.> ".html")
                         else path
        IO.withFile outputPath IO.WriteMode (write rendered)
      Nothing -> TextIO.putStr rendered
  Patch -> putStr $ PatchOutput.patch diff (aSource, bSource)
  where diff = diffTerms aTerm bTerm
        write rendered h = TextIO.hPutStr h rendered