-----------------------------------------------------------------------------
--
  Module       :   Distribution . PackageDescription . PrettyPrint
  Copyright    :       2010
-- License     :  AllRightsReserved
--
-- Maintainer  : 
-- Stability   : provisional
-- Portability : portable
--
-- | Pretty printing for cabal files
--
-----------------------------------------------------------------------------
  All rights reserved . 

 Redistribution and use in source and binary forms , with or without 
 modification , are permitted provided that the following conditions are 
 met : 

     * Redistributions of source code must retain the above copyright 
       notice , this list of conditions and the following disclaimer . 

     * Redistributions in binary form must reproduce the above 
       copyright notice , this list of conditions and the following 
       disclaimer in the documentation and/or other materials provided 
       with the distribution . 

     * Neither the name of   nor the names of other 
       contributors may be used to endorse or promote products derived 
       from this software without specific prior written permission . 

 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
 " AS IS " AND ANY EXPRESS OR IMPLIED WARRANTIES , INCLUDING , BUT NOT 
 LIMITED TO , THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 
 A PARTICULAR PURPOSE ARE DISCLAIMED . IN NO EVENT SHALL THE COPYRIGHT 
 OWNER OR     ANY DIRECT , INDIRECT , INCIDENTAL , 
 SPECIAL , EXEMPLARY , OR CONSEQUENTIAL DAMAGES ( INCLUDING , BUT NOT 
 LIMITED TO , PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES ; LOSS OF USE , 
 DATA , OR PROFITS ; OR BUSINESS INTERRUPTION ) HOWEVER CAUSED AND ON ANY 
 THEORY OF LIABILITY , WHETHER IN CONTRACT , STRICT LIABILITY , OR TORT 
 ( INCLUDING NEGLIGENCE OR OTHERWISE ) ARISING IN ANY WAY OUT OF THE USE 
 OF THIS SOFTWARE , EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE .

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.

    * Redistributions in binary form must reproduce the above
      copyright notice, this list of conditions and the following
      disclaimer in the documentation and/or other materials provided
      with the distribution.

    * Neither the name of Isaac Jones nor the names of other
      contributors may be used to endorse or promote products derived
      from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. -}

module Distribution.PackageDescription.PrettyPrint (
    writeGenericPackageDescription,
    showGenericPackageDescription,
) where

import Data.Monoid (Monoid(mempty))
import Distribution.PackageDescription
       ( Benchmark(..), BenchmarkInterface(..), benchmarkType
       , TestSuite(..), TestSuiteInterface(..), testType
       , SourceRepo(..),
        customFieldsBI, CondTree(..), Condition(..),
        FlagName(..), ConfVar(..), Executable(..), Library(..),
        Flag(..), PackageDescription(..),
        GenericPackageDescription(..))
import Text.PrettyPrint
       (hsep, comma, punctuate, fsep, parens, char, nest, empty,
        isEmpty, ($$), (<+>), colon, (<>), text, vcat, ($+$), Doc, render)
import Distribution.Simple.Utils (writeUTF8File)
import Distribution.ParseUtils (showFreeText, FieldDescr(..))
import Distribution.PackageDescription.Parse (pkgDescrFieldDescrs,binfoFieldDescrs,libFieldDescrs,
       sourceRepoFieldDescrs)
import Distribution.Package (Dependency(..))
import Distribution.Text (Text(..))
import Data.Maybe (isJust, fromJust, isNothing)

indentWith :: Int
indentWith = 4

-- | Recompile with false for regression testing
simplifiedPrinting :: Bool
simplifiedPrinting = False

-- | Writes a .cabal file from a generic package description
writeGenericPackageDescription :: FilePath -> GenericPackageDescription -> IO ()
writeGenericPackageDescription fpath pkg = writeUTF8File fpath (showGenericPackageDescription pkg)

-- | Writes a generic package description to a string
showGenericPackageDescription :: GenericPackageDescription -> String
showGenericPackageDescription            = render . ppGenericPackageDescription

ppGenericPackageDescription :: GenericPackageDescription -> Doc
ppGenericPackageDescription gpd          =
        ppPackageDescription (packageDescription gpd)
        $+$ ppGenPackageFlags (genPackageFlags gpd)
        $+$ ppLibrary (condLibrary gpd)
        $+$ ppExecutables (condExecutables gpd)
        $+$ ppTestSuites (condTestSuites gpd)
        $+$ ppBenchmarks (condBenchmarks gpd)

ppPackageDescription :: PackageDescription -> Doc
ppPackageDescription pd                  =      ppFields pkgDescrFieldDescrs pd
                                                $+$ ppCustomFields (customFieldsPD pd)
                                                $+$ ppSourceRepos (sourceRepos pd)

ppSourceRepos :: [SourceRepo] -> Doc
ppSourceRepos []                         = empty
ppSourceRepos (hd:tl)                    = ppSourceRepo hd $+$ ppSourceRepos tl

ppSourceRepo :: SourceRepo -> Doc
ppSourceRepo repo                        =
    emptyLine $ text "source-repository" <+> disp (repoKind repo) $+$
        (nest indentWith (ppFields sourceRepoFieldDescrs' repo))
  where
    sourceRepoFieldDescrs' = [fd | fd <- sourceRepoFieldDescrs, fieldName fd /= "kind"]

ppFields :: [FieldDescr a] -> a -> Doc
ppFields fields x                        =
    vcat [ ppField name (getter x)
                         | FieldDescr name getter _ <- fields]

ppField :: String -> Doc -> Doc
ppField name fielddoc | isEmpty fielddoc = empty
                      | otherwise        = text name <> colon <+> fielddoc

ppDiffFields :: [FieldDescr a] -> a -> a -> Doc
ppDiffFields fields x y                  =
    vcat [ ppField name (getter x)
                         | FieldDescr name getter _ <- fields,
                            render (getter x) /= render (getter y)]

ppCustomFields :: [(String,String)] -> Doc
ppCustomFields flds                      = vcat [ppCustomField f | f <- flds]

ppCustomField :: (String,String) -> Doc
ppCustomField (name,val)                 = text name <> colon <+> showFreeText val

ppGenPackageFlags :: [Flag] -> Doc
ppGenPackageFlags flds                   = vcat [ppFlag f | f <- flds]

ppFlag :: Flag -> Doc
ppFlag (MkFlag name desc dflt manual)    =
    emptyLine $ text "flag" <+> ppFlagName name $+$
            (nest indentWith ((if null desc
                                then empty
                                else  text "Description: " <+> showFreeText desc) $+$
                     (if dflt then empty else text "Default: False") $+$
                     (if manual then text "Manual: True" else empty)))

ppLibrary :: (Maybe (CondTree ConfVar [Dependency] Library)) -> Doc
ppLibrary Nothing                        = empty
ppLibrary (Just condTree)                =
    emptyLine $ text "library" $+$ nest indentWith (ppCondTree condTree Nothing ppLib)
  where
    ppLib lib Nothing     = ppFields libFieldDescrs lib
                            $$  ppCustomFields (customFieldsBI (libBuildInfo lib))
    ppLib lib (Just plib) = ppDiffFields libFieldDescrs lib plib
                            $$  ppCustomFields (customFieldsBI (libBuildInfo lib))

ppExecutables :: [(String, CondTree ConfVar [Dependency] Executable)] -> Doc
ppExecutables exes                       =
    vcat [emptyLine $ text ("executable " ++ n)
              $+$ nest indentWith (ppCondTree condTree Nothing ppExe)| (n,condTree) <- exes]
  where
    ppExe (Executable _ modulePath' buildInfo') Nothing =
        (if modulePath' == "" then empty else text "main-is:" <+> text modulePath')
            $+$ ppFields binfoFieldDescrs buildInfo'
            $+$  ppCustomFields (customFieldsBI buildInfo')
    ppExe (Executable _ modulePath' buildInfo')
            (Just (Executable _ modulePath2 buildInfo2)) =
            (if modulePath' == "" || modulePath' == modulePath2
                then empty else text "main-is:" <+> text modulePath')
            $+$ ppDiffFields binfoFieldDescrs buildInfo' buildInfo2
            $+$ ppCustomFields (customFieldsBI buildInfo')

ppTestSuites :: [(String, CondTree ConfVar [Dependency] TestSuite)] -> Doc
ppTestSuites suites =
    emptyLine $ vcat [     text ("test-suite " ++ n)
                       $+$ nest indentWith (ppCondTree condTree Nothing ppTestSuite)
                     | (n,condTree) <- suites]
  where
    ppTestSuite testsuite Nothing =
                maybe empty (\t -> text "type:"        <+> disp t)
                            maybeTestType
            $+$ maybe empty (\f -> text "main-is:"     <+> text f)
                            (testSuiteMainIs testsuite)
            $+$ maybe empty (\m -> text "test-module:" <+> disp m)
                            (testSuiteModule testsuite)
            $+$ ppFields binfoFieldDescrs (testBuildInfo testsuite)
            $+$ ppCustomFields (customFieldsBI (testBuildInfo testsuite))
      where
        maybeTestType | testInterface testsuite == mempty = Nothing
                      | otherwise = Just (testType testsuite)

    ppTestSuite (TestSuite _ _ buildInfo' _)
                    (Just (TestSuite _ _ buildInfo2 _)) =
            ppDiffFields binfoFieldDescrs buildInfo' buildInfo2
            $+$ ppCustomFields (customFieldsBI buildInfo')

    testSuiteMainIs test = case testInterface test of
      TestSuiteExeV10 _ f -> Just f
      _                   -> Nothing

    testSuiteModule test = case testInterface test of
      TestSuiteLibV09 _ m -> Just m
      _                   -> Nothing

ppBenchmarks :: [(String, CondTree ConfVar [Dependency] Benchmark)] -> Doc
ppBenchmarks suites =
    emptyLine $ vcat [     text ("benchmark " ++ n)
                       $+$ nest indentWith (ppCondTree condTree Nothing ppBenchmark)
                     | (n,condTree) <- suites]
  where
    ppBenchmark benchmark Nothing =
                maybe empty (\t -> text "type:"        <+> disp t)
                            maybeBenchmarkType
            $+$ maybe empty (\f -> text "main-is:"     <+> text f)
                            (benchmarkMainIs benchmark)
            $+$ ppFields binfoFieldDescrs (benchmarkBuildInfo benchmark)
            $+$ ppCustomFields (customFieldsBI (benchmarkBuildInfo benchmark))
      where
        maybeBenchmarkType | benchmarkInterface benchmark == mempty = Nothing
                           | otherwise = Just (benchmarkType benchmark)

    ppBenchmark (Benchmark _ _ buildInfo' _)
                    (Just (Benchmark _ _ buildInfo2 _)) =
            ppDiffFields binfoFieldDescrs buildInfo' buildInfo2
            $+$ ppCustomFields (customFieldsBI buildInfo')

    benchmarkMainIs benchmark = case benchmarkInterface benchmark of
      BenchmarkExeV10 _ f -> Just f
      _                   -> Nothing

ppCondition :: Condition ConfVar -> Doc
ppCondition (Var x)                      = ppConfVar x
ppCondition (Lit b)                      = text (show b)
ppCondition (CNot c)                     = char '!' <> (ppCondition c)
ppCondition (COr c1 c2)                  = parens (hsep [ppCondition c1, text "||"
                                                         <+> ppCondition c2])
ppCondition (CAnd c1 c2)                 = parens (hsep [ppCondition c1, text "&&"
                                                         <+> ppCondition c2])
ppConfVar :: ConfVar -> Doc
ppConfVar (OS os)                        = text "os"   <> parens (disp os)
ppConfVar (Arch arch)                    = text "arch" <> parens (disp arch)
ppConfVar (Flag name)                    = text "flag" <> parens (ppFlagName name)
ppConfVar (Impl c v)                     = text "impl" <> parens (disp c <+> disp v)

ppFlagName :: FlagName -> Doc
ppFlagName (FlagName name)               = text name

ppCondTree :: CondTree ConfVar [Dependency] a -> Maybe a -> (a -> Maybe a -> Doc) ->  Doc
ppCondTree ct@(CondNode it deps ifs) mbIt ppIt =
    let res = ppDeps deps
                $+$ (vcat $ map ppIf ifs)
                $+$ ppIt it mbIt
    in if isJust mbIt && isEmpty res
        then ppCondTree ct Nothing ppIt
        else res
  where
    ppIf (c,thenTree,mElseTree)          =
        ((emptyLine $ text "if" <+> ppCondition c) $$
          nest indentWith (ppCondTree thenTree
                    (if simplifiedPrinting then (Just it) else Nothing) ppIt))
        $+$ (if isNothing mElseTree
                then empty
                else text "else"
                    $$ nest indentWith (ppCondTree (fromJust mElseTree)
                        (if simplifiedPrinting then (Just it) else Nothing) ppIt))

ppDeps :: [Dependency] -> Doc
ppDeps []                                = empty
ppDeps deps                              =
    text "build-depends:" <+> fsep (punctuate comma (map disp deps))

emptyLine :: Doc -> Doc
emptyLine d                              = text " " $+$ d




---------------------------------------------------------------------------

 License     :  AllRightsReserved

 Maintainer  : 
 Stability   : provisional
 Portability : portable

 | Pretty printing for cabal files

---------------------------------------------------------------------------
 | Recompile with false for regression testing
 | Writes a .cabal file from a generic package description
 | Writes a generic package description to a string
  Module       :   Distribution . PackageDescription . PrettyPrint
  Copyright    :       2010
  All rights reserved . 

 Redistribution and use in source and binary forms , with or without 
 modification , are permitted provided that the following conditions are 
 met : 

     * Redistributions of source code must retain the above copyright 
       notice , this list of conditions and the following disclaimer . 

     * Redistributions in binary form must reproduce the above 
       copyright notice , this list of conditions and the following 
       disclaimer in the documentation and/or other materials provided 
       with the distribution . 

     * Neither the name of   nor the names of other 
       contributors may be used to endorse or promote products derived 
       from this software without specific prior written permission . 

 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
 " AS IS " AND ANY EXPRESS OR IMPLIED WARRANTIES , INCLUDING , BUT NOT 
 LIMITED TO , THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 
 A PARTICULAR PURPOSE ARE DISCLAIMED . IN NO EVENT SHALL THE COPYRIGHT 
 OWNER OR     ANY DIRECT , INDIRECT , INCIDENTAL , 
 SPECIAL , EXEMPLARY , OR CONSEQUENTIAL DAMAGES ( INCLUDING , BUT NOT 
 LIMITED TO , PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES ; LOSS OF USE , 
 DATA , OR PROFITS ; OR BUSINESS INTERRUPTION ) HOWEVER CAUSED AND ON ANY 
 THEORY OF LIABILITY , WHETHER IN CONTRACT , STRICT LIABILITY , OR TORT 
 ( INCLUDING NEGLIGENCE OR OTHERWISE ) ARISING IN ANY WAY OUT OF THE USE 
 OF THIS SOFTWARE , EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE .

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:

    * Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.

    * Redistributions in binary form must reproduce the above
      copyright notice, this list of conditions and the following
      disclaimer in the documentation and/or other materials provided
      with the distribution.

    * Neither the name of Isaac Jones nor the names of other
      contributors may be used to endorse or promote products derived
      from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. -}

module Distribution.PackageDescription.PrettyPrint (
    writeGenericPackageDescription,
    showGenericPackageDescription,
) where

import Data.Monoid (Monoid(mempty))
import Distribution.PackageDescription
       ( Benchmark(..), BenchmarkInterface(..), benchmarkType
       , TestSuite(..), TestSuiteInterface(..), testType
       , SourceRepo(..),
        customFieldsBI, CondTree(..), Condition(..),
        FlagName(..), ConfVar(..), Executable(..), Library(..),
        Flag(..), PackageDescription(..),
        GenericPackageDescription(..))
import Text.PrettyPrint
       (hsep, comma, punctuate, fsep, parens, char, nest, empty,
        isEmpty, ($$), (<+>), colon, (<>), text, vcat, ($+$), Doc, render)
import Distribution.Simple.Utils (writeUTF8File)
import Distribution.ParseUtils (showFreeText, FieldDescr(..))
import Distribution.PackageDescription.Parse (pkgDescrFieldDescrs,binfoFieldDescrs,libFieldDescrs,
       sourceRepoFieldDescrs)
import Distribution.Package (Dependency(..))
import Distribution.Text (Text(..))
import Data.Maybe (isJust, fromJust, isNothing)

indentWith :: Int
indentWith = 4

simplifiedPrinting :: Bool
simplifiedPrinting = False

writeGenericPackageDescription :: FilePath -> GenericPackageDescription -> IO ()
writeGenericPackageDescription fpath pkg = writeUTF8File fpath (showGenericPackageDescription pkg)

showGenericPackageDescription :: GenericPackageDescription -> String
showGenericPackageDescription            = render . ppGenericPackageDescription

ppGenericPackageDescription :: GenericPackageDescription -> Doc
ppGenericPackageDescription gpd          =
        ppPackageDescription (packageDescription gpd)
        $+$ ppGenPackageFlags (genPackageFlags gpd)
        $+$ ppLibrary (condLibrary gpd)
        $+$ ppExecutables (condExecutables gpd)
        $+$ ppTestSuites (condTestSuites gpd)
        $+$ ppBenchmarks (condBenchmarks gpd)

ppPackageDescription :: PackageDescription -> Doc
ppPackageDescription pd                  =      ppFields pkgDescrFieldDescrs pd
                                                $+$ ppCustomFields (customFieldsPD pd)
                                                $+$ ppSourceRepos (sourceRepos pd)

ppSourceRepos :: [SourceRepo] -> Doc
ppSourceRepos []                         = empty
ppSourceRepos (hd:tl)                    = ppSourceRepo hd $+$ ppSourceRepos tl

ppSourceRepo :: SourceRepo -> Doc
ppSourceRepo repo                        =
    emptyLine $ text "source-repository" <+> disp (repoKind repo) $+$
        (nest indentWith (ppFields sourceRepoFieldDescrs' repo))
  where
    sourceRepoFieldDescrs' = [fd | fd <- sourceRepoFieldDescrs, fieldName fd /= "kind"]

ppFields :: [FieldDescr a] -> a -> Doc
ppFields fields x                        =
    vcat [ ppField name (getter x)
                         | FieldDescr name getter _ <- fields]

ppField :: String -> Doc -> Doc
ppField name fielddoc | isEmpty fielddoc = empty
                      | otherwise        = text name <> colon <+> fielddoc

ppDiffFields :: [FieldDescr a] -> a -> a -> Doc
ppDiffFields fields x y                  =
    vcat [ ppField name (getter x)
                         | FieldDescr name getter _ <- fields,
                            render (getter x) /= render (getter y)]

ppCustomFields :: [(String,String)] -> Doc
ppCustomFields flds                      = vcat [ppCustomField f | f <- flds]

ppCustomField :: (String,String) -> Doc
ppCustomField (name,val)                 = text name <> colon <+> showFreeText val

ppGenPackageFlags :: [Flag] -> Doc
ppGenPackageFlags flds                   = vcat [ppFlag f | f <- flds]

ppFlag :: Flag -> Doc
ppFlag (MkFlag name desc dflt manual)    =
    emptyLine $ text "flag" <+> ppFlagName name $+$
            (nest indentWith ((if null desc
                                then empty
                                else  text "Description: " <+> showFreeText desc) $+$
                     (if dflt then empty else text "Default: False") $+$
                     (if manual then text "Manual: True" else empty)))

ppLibrary :: (Maybe (CondTree ConfVar [Dependency] Library)) -> Doc
ppLibrary Nothing                        = empty
ppLibrary (Just condTree)                =
    emptyLine $ text "library" $+$ nest indentWith (ppCondTree condTree Nothing ppLib)
  where
    ppLib lib Nothing     = ppFields libFieldDescrs lib
                            $$  ppCustomFields (customFieldsBI (libBuildInfo lib))
    ppLib lib (Just plib) = ppDiffFields libFieldDescrs lib plib
                            $$  ppCustomFields (customFieldsBI (libBuildInfo lib))

ppExecutables :: [(String, CondTree ConfVar [Dependency] Executable)] -> Doc
ppExecutables exes                       =
    vcat [emptyLine $ text ("executable " ++ n)
              $+$ nest indentWith (ppCondTree condTree Nothing ppExe)| (n,condTree) <- exes]
  where
    ppExe (Executable _ modulePath' buildInfo') Nothing =
        (if modulePath' == "" then empty else text "main-is:" <+> text modulePath')
            $+$ ppFields binfoFieldDescrs buildInfo'
            $+$  ppCustomFields (customFieldsBI buildInfo')
    ppExe (Executable _ modulePath' buildInfo')
            (Just (Executable _ modulePath2 buildInfo2)) =
            (if modulePath' == "" || modulePath' == modulePath2
                then empty else text "main-is:" <+> text modulePath')
            $+$ ppDiffFields binfoFieldDescrs buildInfo' buildInfo2
            $+$ ppCustomFields (customFieldsBI buildInfo')

ppTestSuites :: [(String, CondTree ConfVar [Dependency] TestSuite)] -> Doc
ppTestSuites suites =
    emptyLine $ vcat [     text ("test-suite " ++ n)
                       $+$ nest indentWith (ppCondTree condTree Nothing ppTestSuite)
                     | (n,condTree) <- suites]
  where
    ppTestSuite testsuite Nothing =
                maybe empty (\t -> text "type:"        <+> disp t)
                            maybeTestType
            $+$ maybe empty (\f -> text "main-is:"     <+> text f)
                            (testSuiteMainIs testsuite)
            $+$ maybe empty (\m -> text "test-module:" <+> disp m)
                            (testSuiteModule testsuite)
            $+$ ppFields binfoFieldDescrs (testBuildInfo testsuite)
            $+$ ppCustomFields (customFieldsBI (testBuildInfo testsuite))
      where
        maybeTestType | testInterface testsuite == mempty = Nothing
                      | otherwise = Just (testType testsuite)

    ppTestSuite (TestSuite _ _ buildInfo' _)
                    (Just (TestSuite _ _ buildInfo2 _)) =
            ppDiffFields binfoFieldDescrs buildInfo' buildInfo2
            $+$ ppCustomFields (customFieldsBI buildInfo')

    testSuiteMainIs test = case testInterface test of
      TestSuiteExeV10 _ f -> Just f
      _                   -> Nothing

    testSuiteModule test = case testInterface test of
      TestSuiteLibV09 _ m -> Just m
      _                   -> Nothing

ppBenchmarks :: [(String, CondTree ConfVar [Dependency] Benchmark)] -> Doc
ppBenchmarks suites =
    emptyLine $ vcat [     text ("benchmark " ++ n)
                       $+$ nest indentWith (ppCondTree condTree Nothing ppBenchmark)
                     | (n,condTree) <- suites]
  where
    ppBenchmark benchmark Nothing =
                maybe empty (\t -> text "type:"        <+> disp t)
                            maybeBenchmarkType
            $+$ maybe empty (\f -> text "main-is:"     <+> text f)
                            (benchmarkMainIs benchmark)
            $+$ ppFields binfoFieldDescrs (benchmarkBuildInfo benchmark)
            $+$ ppCustomFields (customFieldsBI (benchmarkBuildInfo benchmark))
      where
        maybeBenchmarkType | benchmarkInterface benchmark == mempty = Nothing
                           | otherwise = Just (benchmarkType benchmark)

    ppBenchmark (Benchmark _ _ buildInfo' _)
                    (Just (Benchmark _ _ buildInfo2 _)) =
            ppDiffFields binfoFieldDescrs buildInfo' buildInfo2
            $+$ ppCustomFields (customFieldsBI buildInfo')

    benchmarkMainIs benchmark = case benchmarkInterface benchmark of
      BenchmarkExeV10 _ f -> Just f
      _                   -> Nothing

ppCondition :: Condition ConfVar -> Doc
ppCondition (Var x)                      = ppConfVar x
ppCondition (Lit b)                      = text (show b)
ppCondition (CNot c)                     = char '!' <> (ppCondition c)
ppCondition (COr c1 c2)                  = parens (hsep [ppCondition c1, text "||"
                                                         <+> ppCondition c2])
ppCondition (CAnd c1 c2)                 = parens (hsep [ppCondition c1, text "&&"
                                                         <+> ppCondition c2])
ppConfVar :: ConfVar -> Doc
ppConfVar (OS os)                        = text "os"   <> parens (disp os)
ppConfVar (Arch arch)                    = text "arch" <> parens (disp arch)
ppConfVar (Flag name)                    = text "flag" <> parens (ppFlagName name)
ppConfVar (Impl c v)                     = text "impl" <> parens (disp c <+> disp v)

ppFlagName :: FlagName -> Doc
ppFlagName (FlagName name)               = text name

ppCondTree :: CondTree ConfVar [Dependency] a -> Maybe a -> (a -> Maybe a -> Doc) ->  Doc
ppCondTree ct@(CondNode it deps ifs) mbIt ppIt =
    let res = ppDeps deps
                $+$ (vcat $ map ppIf ifs)
                $+$ ppIt it mbIt
    in if isJust mbIt && isEmpty res
        then ppCondTree ct Nothing ppIt
        else res
  where
    ppIf (c,thenTree,mElseTree)          =
        ((emptyLine $ text "if" <+> ppCondition c) $$
          nest indentWith (ppCondTree thenTree
                    (if simplifiedPrinting then (Just it) else Nothing) ppIt))
        $+$ (if isNothing mElseTree
                then empty
                else text "else"
                    $$ nest indentWith (ppCondTree (fromJust mElseTree)
                        (if simplifiedPrinting then (Just it) else Nothing) ppIt))

ppDeps :: [Dependency] -> Doc
ppDeps []                                = empty
ppDeps deps                              =
    text "build-depends:" <+> fsep (punctuate comma (map disp deps))

emptyLine :: Doc -> Doc
emptyLine d                              = text " " $+$ d



