{-# LANGUAGE CPP #-}
module Distribution.Nixpkgs.Haskell.Stack where

import Control.Lens
import Data.Maybe (fromMaybe)
import Data.Text as T
import Distribution.Compiler as Compiler
import Distribution.Nixpkgs.Fetch
import Distribution.Nixpkgs.Haskell.Derivation
import Distribution.Nixpkgs.Haskell.FromCabal as FromCabal
import Distribution.Nixpkgs.Haskell.FromStack as FromStack
import Distribution.Nixpkgs.Haskell.PackageSourceSpec as PackageSourceSpec
import Distribution.PackageDescription as PackageDescription
import Distribution.System as System
import Network.URI as URI
import Stack.Config


newtype HackageDb = HackageDb { fromHackageDB :: T.Text }
  deriving (Eq, Ord, Show)

makePrisms ''HackageDb

unHackageDb :: HackageDb -> String
unHackageDb = T.unpack . fromHackageDB

data StackPackagesConfig = StackPackagesConfig
  { _spcHaskellResolver   :: !HaskellResolver
  , _spcNixpkgsResolver   :: !NixpkgsResolver
  , _spcTargetPlatform    :: !Platform
  , _spcTargetCompiler    :: !CompilerInfo
  , _spcFlagAssignment    :: !FlagAssignment
  , _spcDoCheckPackages   :: !Bool
  , _spcDoHaddockPackages :: !Bool
  , _spcDoCheckStackage   :: !Bool
  , _spcDoHaddockStackage :: !Bool
  }

makeLenses ''StackPackagesConfig

getStackPackageFromDb
  :: Maybe HackageDb
  -> StackPackage
  -> IO Package
getStackPackageFromDb optHackageDb stackPackage =
#if MIN_VERSION_cabal2nix(2,6,0)
  PackageSourceSpec.getPackage
    False
    (unHackageDb <$> optHackageDb)
    Nothing
    (stackLocationToSource (stackPackage ^. spLocation) (stackPackage ^. spDir))
#else
  PackageSourceSpec.getPackage
    (unHackageDb <$> optHackageDb)
    (stackLocationToSource (stackPackage ^. spLocation) (stackPackage ^. spDir))
#endif

stackLocationToSource
  :: PackageLocation
     -- ^ Subdirectory in the package containing cabal file.
  -> Maybe FilePath
  -> Source
stackLocationToSource pl mCabalDir = case pl of
  HackagePackage p -> Source
    { sourceUrl      = "cabal://" ++ T.unpack p
    , sourceRevision = mempty
    , sourceHash     = UnknownHash
    , sourceCabalDir = cabalDir }
  StackFilePath p  -> Source
    { sourceUrl      = p
    , sourceRevision = mempty
    , sourceHash     = UnknownHash
    , sourceCabalDir = cabalDir }
  StackUri uri     -> Source
    { sourceUrl      = URI.uriToString id uri mempty
    , sourceRevision = mempty
    , sourceHash     = UnknownHash
    , sourceCabalDir = cabalDir }
  StackRepo r      -> Source
    { sourceUrl      = T.unpack $ r ^. rUri
    , sourceRevision = T.unpack $ r ^. rCommit
    , sourceHash     = UnknownHash
    , sourceCabalDir = cabalDir }
  where
    cabalDir = fromMaybe mempty mCabalDir

packageDerivation
  :: StackPackagesConfig
  -> Maybe HackageDb
  -> StackPackage
  -> IO Derivation
packageDerivation conf optHackageDb stackPackage = do
  pkg <- getStackPackageFromDb optHackageDb stackPackage
  let
    drv = genericPackageDerivation conf pkg
      & subpath %~ flip fromMaybe (stackPackage ^. spDir)
    isExtraDep = stackPackage ^. spExtraDep
    pconf = PackageConfig
      { enableCheck = if isExtraDep then conf ^. spcDoCheckStackage else conf ^. spcDoCheckPackages
      , enableHaddock = if isExtraDep then conf ^. spcDoHaddockStackage else conf ^. spcDoHaddockPackages }
  return $ finalizePackage pkg pconf drv

genericPackageDerivation
  :: StackPackagesConfig
  -> Package
  -> Derivation
genericPackageDerivation conf pkg =
  FromCabal.fromGenericPackageDescription
    (conf ^. spcHaskellResolver)
    (conf ^. spcNixpkgsResolver)
    (conf ^. spcTargetPlatform)
    (conf ^. spcTargetCompiler)
    (conf ^. spcFlagAssignment)
    []
    (pkgCabal pkg)