-- A program for generating a Gentoo ebuild from a .cabal file
--
-- Author : Duncan Coutts <dcoutts@gentoo.org>
--
-- Created: 21 July 2005
--
-- Copyright (C) 2005 Duncan Coutts
--
-- This library is free software; you can redistribute it and/or
-- modify it under the terms of the GNU General Public License
-- as published by the Free Software Foundation; either version 2
-- of the License, or (at your option) any later version.
--
-- This library is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-- General Public License for more details.
--
-- |
-- Maintainer  : haskell@gentoo.org
--
-- cabal2ebuild - a program for generating a Gentoo ebuild from a .cabal file
--
module Cabal2Ebuild
        (cabal2ebuild
        ,convertDependencies
        ,convertDependency
        ,default_ghc_dependency) where

import qualified Distribution.PackageDescription as Cabal
                                                (PackageDescription(..))
import qualified Distribution.Package as Cabal  (PackageIdentifier(..)
                                                , Dependency(..)
                                                , PackageName(..))
import qualified Distribution.Version as Cabal  (VersionRange, foldVersionRange')
import Distribution.Text (display)

import Data.Char          (toLower,isUpper)

import Portage.Dependency
import qualified Portage.PackageId as Portage
import qualified Portage.EBuild as Portage
import qualified Portage.EBuild as E
import Portage.Version

default_ghc_dependency :: Dependency
default_ghc_dependency = OrLaterVersionOf (Version [6,8,1] Nothing [] 0) (Portage.mkPackageName "dev-lang" "ghc")

cabal2ebuild :: Cabal.PackageDescription -> Portage.EBuild
cabal2ebuild pkg = Portage.ebuildTemplate {
    E.name        = map toLower cabalPkgName,
    E.version     = display (Cabal.pkgVersion (Cabal.package pkg)),
    E.description = if null (Cabal.synopsis pkg) then Cabal.description pkg
                                               else Cabal.synopsis pkg,
    E.homepage        = thisHomepage,
    E.src_uri         = thisSRC_URI,
    E.license         = Cabal.license pkg,
    E.my_pn           = if any isUpper cabalPkgName then Just cabalPkgName else Nothing,
    E.features        = E.features E.ebuildTemplate
                   ++ (if hasExe then ["bin"] else [])
                   ++ maybe [] (const (["lib","profile","haddock"]
                        ++ if cabalPkgName == "hscolour" then [] else ["hscolour"])
                        ) (Cabal.library pkg) -- hscolour can't colour its own sources
  } where
        cabalPkgName = display $ Cabal.pkgName (Cabal.package pkg)
        hasExe = (not . null) (Cabal.executables pkg) 
        thisHomepage = if (null $ Cabal.homepage pkg)
                         then E.homepage E.ebuildTemplate
                         else Cabal.homepage pkg
        thisSRC_URI = if (null $ Cabal.pkgUrl pkg)
                        then E.src_uri E.ebuildTemplate
                        else Cabal.pkgUrl pkg

convertDependencies :: Portage.Category -> [Cabal.Dependency] -> [Dependency]
convertDependencies category = concatMap (convertDependency category)

convertDependency :: Portage.Category -> Cabal.Dependency -> [Dependency]
convertDependency _category (Cabal.Dependency pname@(Cabal.PackageName _name) _)
  | pname `elem` coreLibs = []      -- no explicit dep on core libs
convertDependency category (Cabal.Dependency pname versionRange)
  = convert versionRange
  where
    -- XXX: not always true, we should look properly for deps in the overlay
    -- to find the correct category
    pn = Portage.PackageName category (Portage.normalizeCabalPackageName pname)
    convert :: Cabal.VersionRange -> [Dependency]
    convert =  Cabal.foldVersionRange'
             (          [AnyVersionOf                            pn] -- ^ @\"-any\"@ version
            )(\v     -> [ThisVersionOf      (fromCabalVersion v) pn] -- ^ @\"== v\"@
            )(\v     -> [LaterVersionOf     (fromCabalVersion v) pn] -- ^ @\"> v\"@
            )(\v     -> [EarlierVersionOf   (fromCabalVersion v) pn] -- ^ @\"< v\"@
            )(\v     -> [OrLaterVersionOf   (fromCabalVersion v) pn] -- ^ @\">= v\"@
            )(\v     -> [OrEarlierVersionOf (fromCabalVersion v) pn] -- ^ @\"<= v\"@
            )(\v _   -> [ThisMajorOf        (fromCabalVersion v) pn] -- ^ @\"== v.*\"@ wildcard. (incl lower, excl upper)
            )(\g1 g2 -> [DependEither (flatten g1 ++ flatten g2)   ] -- ^ @\"_ || _\"@ union
            )(\r1 r2 -> r1 ++ r2
            )
      where
      flatten :: [Dependency] -> [[Dependency]]
      flatten [DependEither ds] = concatMap flatten ds
      flatten other = [other]


coreLibs :: [Cabal.PackageName]
coreLibs = map Cabal.PackageName
  ["array"
  ,"base"
  ,"bytestring"   -- intentionally no ebuild. use ghc's version
                  -- to avoid dreaded 'diamond dependency' problem
  ,"containers"
  ,"directory"
  --,"editline"
  ,"filepath"     -- intentionally no ebuild. use ghc's version
  ,"ghc"
  ,"ghc-prim"
  ,"haskell98"
  ,"hpc"          --has ebuild, but only in the overlay
  ,"integer"
  ,"old-locale"
  ,"old-time"
  ,"packedstring"
  ,"pretty"
  ,"process"
  ,"random"
  ,"readline"     --has ebuild, but only in the overlay
  ,"rts"
  ,"syb"          -- intentionally no ebuild. use ghc's version
  ,"template-haskell"
  ,"unix"         --has ebuild, but only in the overlay
  ]