{-# LANGUAGE DeriveDataTypeable #-}
{-# LANGUAGE DeriveGeneric      #-}
module Distribution.Types.Dependency
  ( Dependency(..)
  , mkDependency
  , depPkgName
  , depVerRange
  , depLibraries
  , simplifyDependency
  , mainLibSet
  ) where

import Distribution.Compat.Prelude
import Prelude ()

import Distribution.Types.VersionRange (isAnyVersionLight)
import Distribution.Version            (VersionRange, anyVersion, simplifyVersionRange)

import Distribution.CabalSpecVersion
import Distribution.Compat.CharParsing        (char, spaces)
import Distribution.Compat.Parsing            (between, option)
import Distribution.Parsec
import Distribution.Pretty
import Distribution.Types.LibraryName
import Distribution.Types.PackageName
import Distribution.Types.UnqualComponentName

import qualified Distribution.Compat.NonEmptySet as NES
import qualified Text.PrettyPrint                as PP

-- | Describes a dependency on a source package (API)
--
-- /Invariant:/ package name does not appear as 'LSubLibName' in
-- set of library names.
--
-- /Note:/ 'Dependency' is not an instance of 'Ord', and so it cannot be used
-- in 'Set' or as the key to a 'Map'.  For these and similar use cases see
-- 'DependencyMap'.
--
data Dependency = Dependency
                    PackageName
                    VersionRange
                    (NonEmptySet LibraryName)
                    -- ^ The set of libraries required from the package.
                    -- Only the selected libraries will be built.
                    -- It does not affect the cabal-install solver yet.
                  deriving (Generic, Read, Show, Eq, Typeable, Data)

depPkgName :: Dependency -> PackageName
depPkgName (Dependency pn _ _) = pn

depVerRange :: Dependency -> VersionRange
depVerRange (Dependency _ vr _) = vr

depLibraries :: Dependency -> NonEmptySet LibraryName
depLibraries (Dependency _ _ cs) = cs

-- | Smart constructor of 'Dependency'.
--
-- If 'PackageName' is appears as 'LSubLibName' in a set of sublibraries,
-- it is automatically converted to 'LMainLibName'.
--
-- @since 3.4.0.0
--
mkDependency :: PackageName -> VersionRange -> NonEmptySet LibraryName -> Dependency
mkDependency pn vr lb = Dependency pn vr (NES.map conv lb)
  where
    pn' = packageNameToUnqualComponentName pn

    conv l@LMainLibName                 = l
    conv l@(LSubLibName ln) | ln == pn' = LMainLibName
                            | otherwise = l

instance Binary Dependency
instance Structured Dependency
instance NFData Dependency where rnf = genericRnf

-- |
--
-- >>> prettyShow $ Dependency "pkg" anyVersion mainLibSet
-- "pkg"
--
-- >>> prettyShow $ Dependency "pkg" anyVersion $ NES.insert (LSubLibName "sublib") mainLibSet
-- "pkg:{pkg, sublib}"
--
-- >>> prettyShow $ Dependency "pkg" anyVersion $ NES.singleton (LSubLibName "sublib")
-- "pkg:sublib"
--
-- >>> prettyShow $ Dependency "pkg" anyVersion $ NES.insert (LSubLibName "sublib-b") $ NES.singleton (LSubLibName "sublib-a")
-- "pkg:{sublib-a, sublib-b}"
--
instance Pretty Dependency where
    pretty (Dependency name ver sublibs) = withSubLibs (pretty name) <+> pver
      where
        -- TODO: change to isAnyVersion after #6736
        pver | isAnyVersionLight ver = PP.empty
             | otherwise             = pretty ver

        withSubLibs doc = case NES.toList sublibs of
            [LMainLibName]   -> doc
            [LSubLibName uq] -> doc <<>> PP.colon <<>> pretty uq
            _                -> doc <<>> PP.colon <<>> PP.braces prettySublibs

        prettySublibs = PP.hsep $ PP.punctuate PP.comma $ prettySublib <$> NES.toList sublibs

        prettySublib LMainLibName     = PP.text $ unPackageName name
        prettySublib (LSubLibName un) = PP.text $ unUnqualComponentName un

-- |
--
-- >>> simpleParsec "mylib:sub" :: Maybe Dependency
-- Just (Dependency (PackageName "mylib") (OrLaterVersion (mkVersion [0])) (fromNonEmpty (LSubLibName (UnqualComponentName "sub") :| [])))
--
-- >>> simpleParsec "mylib:{sub1,sub2}" :: Maybe Dependency
-- Just (Dependency (PackageName "mylib") (OrLaterVersion (mkVersion [0])) (fromNonEmpty (LSubLibName (UnqualComponentName "sub1") :| [LSubLibName (UnqualComponentName "sub2")])))
--
-- >>> simpleParsec "mylib:{ sub1 , sub2 }" :: Maybe Dependency
-- Just (Dependency (PackageName "mylib") (OrLaterVersion (mkVersion [0])) (fromNonEmpty (LSubLibName (UnqualComponentName "sub1") :| [LSubLibName (UnqualComponentName "sub2")])))
--
-- >>> simpleParsec "mylib:{ sub1 , sub2 } ^>= 42" :: Maybe Dependency
-- Just (Dependency (PackageName "mylib") (MajorBoundVersion (mkVersion [42])) (fromNonEmpty (LSubLibName (UnqualComponentName "sub1") :| [LSubLibName (UnqualComponentName "sub2")])))
--
-- >>> simpleParsec "mylib:{ } ^>= 42" :: Maybe Dependency
-- Nothing
--
-- >>> traverse_ print (map simpleParsec ["mylib:mylib", "mylib:{mylib}", "mylib:{mylib,sublib}" ] :: [Maybe Dependency])
-- Just (Dependency (PackageName "mylib") (OrLaterVersion (mkVersion [0])) (fromNonEmpty (LMainLibName :| [])))
-- Just (Dependency (PackageName "mylib") (OrLaterVersion (mkVersion [0])) (fromNonEmpty (LMainLibName :| [])))
-- Just (Dependency (PackageName "mylib") (OrLaterVersion (mkVersion [0])) (fromNonEmpty (LMainLibName :| [LSubLibName (UnqualComponentName "sublib")])))
--
-- Spaces around colon are not allowed:
--
-- >>> map simpleParsec ["mylib: sub", "mylib :sub", "mylib: {sub1,sub2}", "mylib :{sub1,sub2}"] :: [Maybe Dependency]
-- [Nothing,Nothing,Nothing,Nothing]
--
-- Sublibrary syntax is accepted since @cabal-version: 3.0@
--
-- >>> map (`simpleParsec'` "mylib:sub") [CabalSpecV2_4, CabalSpecV3_0] :: [Maybe Dependency]
-- [Nothing,Just (Dependency (PackageName "mylib") (OrLaterVersion (mkVersion [0])) (fromNonEmpty (LSubLibName (UnqualComponentName "sub") :| [])))]
--
instance Parsec Dependency where
    parsec = do
        name <- parsec

        libs <- option mainLibSet $ do
          _ <- char ':'
          versionGuardMultilibs
          NES.singleton <$> parseLib <|> parseMultipleLibs

        spaces -- https://github.com/haskell/cabal/issues/5846

        ver  <- parsec <|> pure anyVersion
        return $ mkDependency name ver libs
      where
        parseLib          = LSubLibName <$> parsec
        parseMultipleLibs = between
            (char '{' *> spaces)
            (spaces *> char '}')
            (NES.fromNonEmpty <$> parsecCommaNonEmpty parseLib)

versionGuardMultilibs :: CabalParsing m => m ()
versionGuardMultilibs = do
  csv <- askCabalSpecVersion
  when (csv < CabalSpecV3_0) $ fail $ unwords
    [ "Sublibrary dependency syntax used."
    , "To use this syntax the package needs to specify at least 'cabal-version: 3.0'."
    , "Alternatively, if you are depending on an internal library, you can write"
    , "directly the library name as it were a package."
    ]

-- | Library set with main library.
--
-- @since 3.4.0.0
mainLibSet :: NonEmptySet LibraryName
mainLibSet = NES.singleton LMainLibName

-- | Simplify the 'VersionRange' expression in a 'Dependency'.
-- See 'simplifyVersionRange'.
--
simplifyDependency :: Dependency -> Dependency
simplifyDependency (Dependency name range comps) =
  Dependency name (simplifyVersionRange range) comps
