{-
 DB.hsc: Haskell bindings to libdpkg
   Copyright (C) 2011 Clint Adams

 This program 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 3 of the License, or
 (at your option) any later version.

 This program 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.

 You should have received a copy of the GNU General Public License
 along with this program; if not, write to the Free Software
 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
-}

{-# LANGUAGE CPP, ForeignFunctionInterface #-}

#include <bindings.dsl.h>

module Debian.Dpkg.DB (
    msdbInit
  , setDbDir
  , pkgDbFind
  , pkgList
  , getConfigVersion
) where
#strict_import

import Foreign.Ptr (nullPtr)
import Foreign.C.String (withCString, peekCString)
import Foreign.Marshal.Utils (with)
import Control.Monad (liftM, join)
import Control.Monad.Loops (unfoldrM)
import Debian.Dpkg.Types

#include <dpkg/dpkg-db.h>

#callconv modstatdb_open , ccall unsafe , CInt -> IO ()
#callconv push_error_context , ccall unsafe , IO ()
#callconv dpkg_set_progname , ccall unsafe , CString -> IO ()
#callconv dpkg_db_set_dir , ccall unsafe , CString -> IO ()

#callconv pkg_db_iter_new , ccall unsafe , IO (Ptr <pkgiterator>)
#callconv pkg_db_iter_next , ccall unsafe , Ptr <pkgiterator> -> IO (Ptr <pkginfo>)

msdbInit :: IO ()
msdbInit = do
	c'push_error_context
	c'modstatdb_open 0
	withCString "haskell-dpkg" c'dpkg_set_progname

setDbDir :: String -> IO ()
setDbDir x = withCString x  c'dpkg_db_set_dir

pkgDbIterNext :: Ptr C'pkgiterator -> IO (Maybe (Ptr C'pkginfo, Ptr C'pkgiterator))
pkgDbIterNext i = do
         pptr <- c'pkg_db_iter_next i
         if pptr == nullPtr
             then
                return Nothing
             else
                return $ Just (pptr, i)

pkgpList :: IO [Ptr C'pkginfo]
pkgpList = c'pkg_db_iter_new >>= unfoldrM (pkgDbIterNext)

pkgList :: IO [C'pkginfo]
pkgList = pkgpList >>= mapM peek

#callconv pkg_db_find , ccall unsafe ,  CString -> IO (Ptr <pkginfo>)

pkgDbFind :: String -> IO C'pkginfo
pkgDbFind p = withCString p c'pkg_db_find >>= peek

getConfigVersion :: C'pkginfo -> IO String
getConfigVersion p = do
		v <- peekCString (c'versionrevision'version vr)
		r <- peekCString (c'versionrevision'revision vr)
		return $ nonZeroEpoch e ++ v ++ nonNativeRevision r
	where
		nonZeroEpoch e = if e == 0 then "" else (show e) ++ ":"
		nonNativeRevision r = if r == "" then r else "-" ++ r
		e = fromIntegral (c'versionrevision'epoch vr)
		vr = c'pkginfo'configversion p