module System.Installer.Foreign
    (convertFileToC,
     writeFileData,
     cabalCleanHInstallerDir
    )
where

import Control.Concurrent
import Foreign
import Foreign.C
import System.Directory
import System.FilePath
import System.IO
import System.Process
import System.Exit
import Data.Word
import Data.Maybe
import qualified Data.ByteString as B
import Distribution.Simple
import Distribution.Setup
import Distribution.PackageDescription
import Distribution.Simple.LocalBuildInfo

writeCHeaderFile :: Handle -> String -> IO ()
writeCHeaderFile outH name
    = do { hPutStrLn outH lenDeclFuncSig
         ; hPutStrLn outH arrayDeclFuncSig
         }
    where
      lenDeclFuncSig = "const int " ++ name ++ "_length ();"
      arrayDeclFuncSig = "const unsigned char* " ++ name ++ " ();"

writeCFile :: Handle -> String -> B.ByteString -> FilePath -> IO ()
writeCFile outH name content header
    = do { hPutStrLn outH includeLine
         ; hPutStrLn outH lenDecl
         ; hPutStrLn outH arrayDecl
         ; mapM_ writeWord (B.unpack content)
         ; hPutStrLn outH tailDecl
         ; hPutStrLn outH lenDeclFunc
         ; hPutStrLn outH arrayDeclFunc
         }
    where
      len = show . B.length $ content
      includeLine = "#include \"" ++ header ++ "\""
      lenDecl = "const int " ++ name ++ "_length_raw = " ++ len ++ ";"
      arrayDecl = "const unsigned char " ++ name ++
                  "_raw[" ++ len ++ "] = {"
      tailDecl = "};"
      lenDeclFunc = "const int " ++ name ++ "_length () { return " ++
                    name ++ "_length_raw" ++ "; }"
      arrayDeclFunc = "const unsigned char* " ++ name ++ " () { return " ++
                      name ++ "_raw" ++ "; }"
      writeWord :: Word8 -> IO ()
      writeWord wrd = hPutStrLn outH numTxt
          where
            numTxt = (show wrd) ++ ","

convertFileToC :: FilePath -> String -> IO (FilePath)
convertFileToC file clauseName
    = do { createDirectoryIfMissing False hInstallerTmpDir
         ; hHdl <- openBinaryFile pathH WriteMode
         ; writeCHeaderFile hHdl clauseName
         ; hClose hHdl
         ; contentsB <- B.readFile file
         ; cHdl <- openBinaryFile pathC WriteMode
         ; writeCFile cHdl clauseName contentsB leafNameH
         ; hClose cHdl
         ; runCCRelayingOut hInstallerTmpDir leafNameC
         ; return leafNameH
         }
    where
      leafName = takeFileName file
      leafNameNoExts = dropExtensions leafName
      leafNameH = addExtension leafNameNoExts "h"
      leafNameC = addExtension leafNameNoExts "c"
      pathH = combine hInstallerTmpDir leafNameH
      pathC = combine hInstallerTmpDir leafNameC

writeFromPtrToFile :: Ptr CUChar -> Int -> FilePath -> IO ()
writeFromPtrToFile ptr len filePath
    = do { outH <- openBinaryFile filePath WriteMode
         ; hPutBuf outH ptr len
         ; hClose outH
         }

writeFileData :: Ptr CUChar -> CInt -> String -> FilePath -> IO ()
writeFileData ptr len origName path
    = do { isDir <- doesDirectoryExist path
         ; let path' = if isDir then combine path origName else path
         ; writeFromPtrToFile ptr (fromIntegral len) path'
         }

runCCRelayingOut :: FilePath -> FilePath -> IO ExitCode
runCCRelayingOut wd cPath
    = do { (_,outH,errH,procH) <- runInteractiveProcess
                                  "cc" ["-c", cPath] (Just wd) Nothing
         ; forkRelayHandles outH stdout
         ; forkRelayHandles errH stderr
         ; waitForProcess procH
         }

forkRelayHandles :: Handle -> Handle -> IO ThreadId
forkRelayHandles inH outH = forkIO func
    where
      func = hGetContents inH >>= hPutStr outH

hInstallerTmpDir :: FilePath
hInstallerTmpDir = "hinstaller-tmp"

cabalCleanHInstallerDir :: Args -> BuildFlags -> PackageDescription ->
                           LocalBuildInfo -> IO ExitCode
cabalCleanHInstallerDir _ buildflags _ _
    = do { if verbosity > 0
           then print "Cleaning hinstaller-tmp directory..."
           else return ()
         ; dirExists <- doesDirectoryExist hInstallerTmpDir
         ; if dirExists
           then do { removeDirectoryRecursive hInstallerTmpDir
                   ; if verbosity > 0
                     then print "Successfully cleaned hinstaller-tmp directory."
                     else return ()
                   }
           else if verbosity > 0
                then print "hinstaller-tmp directory not found, nothing to clean."
                else return ()
         ; return ExitSuccess
         }
    where
      verbosity = buildVerbose buildflags