{- OSX library copier
 -
 - Copyright 2012 Joey Hess <joey@kitenet.net>
 -
 - Licensed under the GNU GPL version 3 or higher.
 -}

module Build.OSXMkLibs where

import Control.Applicative
import System.Environment
import Data.Maybe
import System.FilePath
import System.Directory
import System.IO
import Control.Monad
import Data.List

import Utility.PartialPrelude
import Utility.Directory
import Utility.Process
import Utility.Monad
import Utility.SafeCommand
import Utility.Path

import qualified Data.Map as M
import qualified Data.Set as S

type LibMap = M.Map FilePath String

{- Recursively find and install libs, until nothing new to install is found. -}
mklibs :: FilePath -> [FilePath] -> LibMap -> IO [FilePath]
mklibs appbase libdirs libmap = do
	(new, libmap') <- installLibs appbase libmap
	if null new
		then return (libdirs++new)
		else mklibs appbase (libdirs++new) libmap'

{- Returns directories into which new libs were installed. -}
installLibs :: FilePath -> LibMap -> IO ([FilePath], LibMap)
installLibs appbase libmap = do
	(needlibs, libmap') <- otool appbase libmap
	libs <- forM needlibs $ \lib -> do
		let dest = appbase </> takeFileName lib
		ifM (doesFileExist dest)
			( return Nothing
			, do
				createDirectoryIfMissing True appbase
				putStrLn $ "installing " ++ lib
				_ <- boolSystem "cp" [File lib, File dest]
				_ <- boolSystem "chmod" [Param "644", File dest]
				return $ Just appbase
			)
	return (catMaybes libs, libmap')

{- Returns libraries to install. -}
otool :: FilePath -> LibMap -> IO ([FilePath], LibMap)
otool appbase libmap = do
	files <- filterM doesFileExist =<< dirContentsRecursive appbase
	process [] files libmap
  where
	unprocessed s = not ("@executable_path" `isInfixOf` s)
	process c [] m = return (nub $ concat c, m)
	process c (file:rest) m = do
		libs <- filter unprocessed . parseOtool
			<$> readProcess "otool" ["-L", file]
		m' <- install_name_tool file libs m
		process (libs:c) rest m'

parseOtool :: String -> [FilePath]
parseOtool = catMaybes . map parse . lines
  where
	parse l
		| "\t" `isPrefixOf` l = headMaybe $ words l
		| otherwise = Nothing

{- Adjusts binaries to use libraries in paths relative to the executable.
 -
 - Assumes all executables are installed into the same directory, and
 - the libraries will be installed in subdirectories that match their
 - absolute paths. -}
install_name_tool :: FilePath -> [FilePath] -> LibMap -> IO LibMap
install_name_tool _ [] libmap = return libmap
install_name_tool binary (lib:rest) libmap = do
	let (libname, libmap') = getLibName lib libmap
	ok <- boolSystem "install_name_tool"
		[ Param "-change"
		, File lib
		, Param $ "@executable_path/" ++ libname
		, File binary
		]
	unless ok $
		hPutStrLn stderr $ "install_name_tool failed for " ++ binary
	install_name_tool binary rest libmap'

{- Uses really short names for the library files it installs, because
 - binaries have arbitrarily short RPATH field limits. -}
getLibName :: FilePath -> LibMap -> (FilePath, LibMap)
getLibName lib libmap = case M.lookup lib libmap of
	Just n -> (n, libmap)
	Nothing -> let n = nextfreename
		in (n, M.insert lib n libmap)
  where
	names = map (\c -> [c]) letters ++
		[[l1, l2] | l1 <- letters, l2 <- letters]
	letters = ['a' .. 'z'] ++ ['A' .. 'Z'] ++ ['0' .. '9']
	used = S.fromList $ M.elems libmap
	nextfreename = fromMaybe (error "ran out of short library names!") $ 
		headMaybe $ dropWhile (`S.member` used) names

main :: IO ()
main = getArgs >>= go
  where
	go [] = error "specify OSXAPP_BASE"
	go (appbase:_) = do
		libdirs <- mklibs appbase [] M.empty
		writeFile (appbase </> "libdirs") $
			unlines $ nub libdirs