{- git-annex command
 -
 - Copyright 2010 Joey Hess <joey@kitenet.net>
 -
 - Licensed under the GNU GPL version 3 or higher.
 -}

{-# LANGUAGE CPP #-}

module Command.Add where

import Common.Annex
import Annex.Exception
import Command
import Types.KeySource
import Backend
import Logs.Location
import Annex.Content
import Annex.Content.Direct
import Annex.Perms
import Annex.Link
import qualified Annex
import qualified Annex.Queue
#ifndef WITH_ANDROID
import Utility.Touch
#endif
import Utility.FileMode
import Config
import Utility.InodeCache

def :: [Command]
def = [notBareRepo $ command "add" paramPaths seek "add files to annex"]

{- Add acts on both files not checked into git yet, and unlocked files. -}
seek :: [CommandSeek]
seek =
	[ withFilesNotInGit start
	, whenNotDirect $ withFilesUnlocked start
	]

{- The add subcommand annexes a file, generating a key for it using a
 - backend, and then moving it into the annex directory and setting up
 - the symlink pointing to its content. -}
start :: FilePath -> CommandStart
start file = ifAnnexed file fixup add
  where
	add = do
		s <- liftIO $ getSymbolicLinkStatus file
		if isSymbolicLink s || not (isRegularFile s)
			then stop
			else do
				showStart "add" file
				next $ perform file
	fixup (key, _) = do
		-- fixup from an interrupted add; the symlink
		-- is present but not yet added to git
		showStart "add" file
		liftIO $ removeFile file
		next $ next $ cleanup file key =<< inAnnex key

{- The file that's being added is locked down before a key is generated,
 - to prevent it from being modified in between. It's hard linked into a
 - temporary location, and its writable bits are removed. It could still be
 - written to by a process that already has it open for writing.
 -
 - Lockdown can fail if a file gets deleted, and Nothing will be returned.
 -}
lockDown :: FilePath -> Annex (Maybe KeySource)
lockDown file = ifM (crippledFileSystem)
	( liftIO $ catchMaybeIO $ do
		cache <- genInodeCache file
		return $ KeySource
			{ keyFilename = file
			, contentLocation = file
			, inodeCache = cache
			}
	, do
		tmp <- fromRepo gitAnnexTmpDir
		createAnnexDirectory tmp
		liftIO $ catchMaybeIO $ do
			preventWrite file
			(tmpfile, h) <- openTempFile tmp (takeFileName file)
			hClose h
			nukeFile tmpfile
			createLink file tmpfile
			cache <- genInodeCache tmpfile
			return $ KeySource
				{ keyFilename = file
				, contentLocation = tmpfile
				, inodeCache = cache
				}
	)

{- Ingests a locked down file into the annex.
 -
 - In direct mode, leaves the file alone, and just updates bookkeeping
 - information.
 -}
ingest :: (Maybe KeySource) -> Annex (Maybe Key)
ingest Nothing = return Nothing
ingest (Just source) = do
	backend <- chooseBackend $ keyFilename source
	k <- genKey source backend
	cache <- liftIO $ genInodeCache $ contentLocation source
	case inodeCache source of
		Nothing -> go k cache
		Just c
			| (Just c == cache) -> go k cache
			| otherwise -> failure
  where
	go k cache = ifM isDirect ( godirect k cache , goindirect k cache )

	goindirect (Just (key, _)) _ = do
		handle (undo (keyFilename source) key) $
			moveAnnex key $ contentLocation source
		liftIO $ nukeFile $ keyFilename source
		return $ Just key
	goindirect Nothing _ = failure

	godirect (Just (key, _)) (Just cache) = do
		writeInodeCache key cache
		void $ addAssociatedFile key $ keyFilename source
		unlessM crippledFileSystem $
			liftIO $ allowWrite $ keyFilename source
		when (contentLocation source /= keyFilename source) $
			liftIO $ nukeFile $ contentLocation source
		return $ Just key
	godirect _ _ = failure

	failure = do
		when (contentLocation source /= keyFilename source) $
			liftIO $ nukeFile $ contentLocation source
		return Nothing		

perform :: FilePath -> CommandPerform
perform file = 
	maybe stop (\key -> next $ cleanup file key True)
		=<< ingest =<< lockDown file

{- On error, put the file back so it doesn't seem to have vanished.
 - This can be called before or after the symlink is in place. -}
undo :: FilePath -> Key -> IOException -> Annex a
undo file key e = do
	whenM (inAnnex key) $ do
		liftIO $ nukeFile file
		handle tryharder $ fromAnnex key file
		logStatus key InfoMissing
	throw e
  where
	-- fromAnnex could fail if the file ownership is weird
	tryharder :: IOException -> Annex ()
	tryharder _ = do
		src <- inRepo $ gitAnnexLocation key
		liftIO $ moveFile src file

{- Creates the symlink to the annexed content, returns the link target. -}
link :: FilePath -> Key -> Bool -> Annex String
link file key hascontent = handle (undo file key) $ do
	l <- calcGitLink file key
	makeAnnexLink l file

#ifndef WITH_ANDROID
	when hascontent $ do
		-- touch the symlink to have the same mtime as the
		-- file it points to
		liftIO $ do
			mtime <- modificationTime <$> getFileStatus file
			touch file (TimeSpec mtime) False
#endif

	return l

{- Note: Several other commands call this, and expect it to 
 - create the link and add it.
 - 
 - In direct mode, when we have the content of the file, it's left as-is,
 - and we just stage a symlink to git.
 - 
 - Otherwise, as long as the filesystem supports symlinks, we use
 - git add, rather than directly staging the symlink to git.
 - Using git add is best because it allows the queuing to work
 - and is faster (staging the symlink runs hash-object commands each time).
 - Also, using git add allows it to skip gitignored files, unless forced
 - to include them.
 -}
cleanup :: FilePath -> Key -> Bool -> CommandCleanup
cleanup file key hascontent = do
	when hascontent $
		logStatus key InfoPresent
	ifM (isDirect <&&> pure hascontent)
		( stageSymlink file =<< hashSymlink =<< calcGitLink file key
		, ifM (coreSymlinks <$> Annex.getGitConfig)
			( do
				_ <- link file key hascontent
				params <- ifM (Annex.getState Annex.force)
					( return [Param "-f"]
					, return []
					)
				Annex.Queue.addCommand "add" (params++[Param "--"]) [file]
			, do
				l <- link file key hascontent
				addAnnexLink l file
			)
		)
	return True