import Distribution.Package
import Distribution.Version
import Distribution.PackageDescription
import Distribution.PackageDescription.Parse
import Distribution.Verbosity
import Data.Maybe
import Data.Version
import Distribution.License
import System.Directory
import Data.List
import Depend

import System.IO.Unsafe
import System.Directory
import System.FilePath
import Control.Applicative

test :: IO ()
test = do
  gpd <- readPackageDescription normal "cabal2ebuild.cabal"
  print $ getName gpd ++ ".ebuild"
  print $ getName gpd ++ ".tar.gz"
  print $ getLicense gpd
  print $ hasLib gpd
  print $ hasEx gpd
  putStrLn $ makeCabalFeatures ( hasLib gpd ) ( hasEx gpd )
  putStrLn $ makeSrcURI $ getName gpd
  putStrLn ""
--  putStrLn $ makeEbuild gpd
  print $ condTreeData $ snd $ head $ condExecutables gpd
  mapM_ print $ condTreeConstraints $ snd $ head $ condExecutables gpd
  print $ synopsis $ packageDescription gpd
  putStrLn ""
  putStr $ ebuildToFile $ gpdToEbuild gpd
  print $ condLibrary gpd
  print $ ebDepends gpd
  

-- main :: IO ()
main = do
  cabal <- fmap ( head . filter ( isSuffixOf ".cabal" ) ) $ getDirectoryContents "."
  gpd <- readPackageDescription normal cabal
  writeFile ( makeFileName gpd ) -- $ makeEbuild gpd
                                 $ ebuildToFile $ gpdToEbuild gpd

makeFileName :: GenericPackageDescription -> String
makeFileName gpd = getName gpd ++ ".ebuild"

-- data EbLicense = BSD3 | GPL | LGPL deriving Show

data EbKWords = X86 | BX86 deriving Show

showEKW :: EbKWords -> String
showEKW X86  = "x86"
showEKW BX86 = "~x86"

data Ebuild = Ebuild {
 
  ebCabalFt :: [ String ] ,
  ebInherit :: String ,
  ebAPI     :: Int ,
  ebDsc     :: String ,
  ebHmpg    :: String ,
  srcURI    :: String ,
  ebLicense :: License ,
  ebSlot    :: Int ,
  ebKWords  :: [ EbKWords ] ,
  ebDepend  :: [ String ]

 } deriving Show

gpdToEbuild :: GenericPackageDescription -> Ebuild
gpdToEbuild gpd = Ebuild {

  ebCabalFt = ft ,
  ebInherit = "haskell-cabal",
  ebAPI     = 3 ,
  ebDsc     = synopsis $ packageDescription gpd ,
  ebHmpg    = homepage $ packageDescription gpd ,
  srcURI    = makeSrcURI ( getName gpd ) ,
  ebLicense = getLicense gpd ,
  ebSlot    = 0 ,
  ebKWords  = [ X86 ] ,
  ebDepend  = ">=dev-lang/ghc-6.10" : "dev-haskell/cabal" : ebDepends gpd

 }
  where
  ft :: [ String ]
  ft = concatMap snd $ filter fst
    [ ( hasLib gpd , [ "lib", "haddock", "profile", "hscolour" ] ),
      ( hasEx gpd  , [ "bin" ] ) ] 
  
ebuildToFile :: Ebuild -> String
ebuildToFile eb =
  "EAPI=" ++ show ( ebAPI eb ) ++ "\n\n" ++
  "CABAL_FEATURES=\"" ++ unwords ( ebCabalFt eb ) ++ "\"\n" ++
  "inherit " ++ ebInherit eb ++ "\n\n" ++
  "DESCRIPTION=" ++ show ( ebDsc eb ) ++ "\n" ++
  "HOMEPAGE=" ++ show ( ebHmpg eb ) ++ "\n" ++
  "SRC_URI=" ++ srcURI eb ++ "\n\n" ++
  "LICENSE=\"" ++ show ( ebLicense eb ) ++ "\"\n" ++
  "SLOT=\"" ++ show ( ebSlot eb ) ++ "\"\n" ++
  "KEYWORDS=\"" ++ unwords ( map showEKW $ ebKWords eb ) ++ "\"\n\n" ++
  "DEPEND=\"" ++ unlines ( ebDepend eb ) ++ "\"\n"

makeEbuild :: GenericPackageDescription -> String
makeEbuild gpd =
  makeCabalFeatures ( hasLib gpd ) ( hasEx gpd ) ++ "\n" ++
  "inherit haskell-cabal\n\n" ++
  "EAPI=3\n\n" ++
  "SRC_URI=" ++ makeSrcURI ( getName gpd ) ++ "\n\n" ++
  makeLicense ( getLicense gpd ) ++ "\n" ++
  "SLOT=\"0\"\n" ++ "KEYWORDS=\"x86\"\n"

makeCabalFeatures :: Bool -> Bool -> String
makeCabalFeatures lb ex
  = let ls = if lb then "lib " else ""
        xs = if ex then "bin " else ""
     in "CABAL_FEATURES=" ++ show ( xs ++ ls ++ "haddock profile hscolour" )

myGentooRepo :: Maybe String
myGentooRepo = unsafePerformIO $ do
	hd <- getHomeDirectory
	let confFile = hd </> ".cabal2ebuild" </> "gentoo_repo.txt"
	fe <- doesFileExist confFile
	if not fe then return Nothing else
		fromConfigFile <$> readFile confFile

fromConfigFile :: String -> Maybe String
fromConfigFile cnt = case lines cnt of
	["local", repo] -> Just repo
	_ -> Nothing

makeSrcURI :: String -> String
-- makeSrcURI nam = show ( "http://homepage3.nifty.com/salamander/second/portage/distfiles/" ++ nam ++ ".tar.gz" )
makeSrcURI nam = case myGentooRepo of
	Just r -> show $ r ++ nam ++ ".tar.gz"
	_ -> show $ "http://hackage.haskell.org/package/" ++ nam ++ "/" ++
		nam ++ ".tar.gz"

makeLicense :: License -> String
makeLicense l = "LICENSE=" ++ show ( show l )

getName :: GenericPackageDescription -> String
getName gpd = let pd = packageDescription gpd
                  PackageName pn = pkgName $ package pd
                  vn = showVersion $ pkgVersion $ package pd
               in pn ++ "-" ++ vn

getLicense :: GenericPackageDescription -> License
getLicense = license . packageDescription

hasLib :: GenericPackageDescription -> Bool
hasLib = isJust . condLibrary

hasEx :: GenericPackageDescription -> Bool
hasEx = not . null . condExecutables