{- git-annex command
 -
 - Copyright 2010, 2013 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
#ifdef WITH_CLIBS
#ifndef __ANDROID__
import Utility.Touch
#endif
#endif
import Config
import Utility.InodeCache
import Annex.FileMatcher
import Annex.ReplaceFile
import Utility.Tmp

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

{- Add acts on both files not checked into git yet, and unlocked files.
 -
 - In direct mode, it acts on any files that have changed. -}
seek :: CommandSeek
seek ps = do
	matcher <- largeFilesMatcher
	let go a = flip a ps $ \file -> ifM (checkFileMatcher matcher file <||> Annex.getState Annex.force)
		( start file
		, stop
		)
	go withFilesNotInGit
	ifM isDirect
		( go withFilesMaybeModified
		, go withFilesUnlocked
		)

{- 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 addpresent add
  where
	add = do
		ms <- liftIO $ catchMaybeIO $ getSymbolicLinkStatus file
		case ms of
			Nothing -> stop
			Just s
				| isSymbolicLink s || not (isRegularFile s) -> stop
				| otherwise -> do
					showStart "add" file
					next $ perform file
	addpresent (key, _) = ifM isDirect
		( ifM (goodContent key file) ( stop , add )
		, fixup key
		)
	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 Nothing =<< inAnnex key

{- The file that's being added is locked down before a key is generated,
 - to prevent it from being modified in between. This lock down is not
 - perfect at best (and pretty weak at worst). For example, it does not
 - guard against files that are already opened for write by another process.
 - So a KeySource is returned. Its inodeCache can be used to detect any
 - changes that might be made to the file after it was locked down.
 -
 - When possible, the file is hard linked to a temp directory. This guards
 - against some changes, like deletion or overwrite of the file, and
 - allows lsof checks to be done more efficiently when adding a lot of files.
 -
 - Lockdown can fail if a file gets deleted, and Nothing will be returned.
 -}
lockDown :: FilePath -> Annex (Maybe KeySource)
lockDown file = ifM crippledFileSystem
	( liftIO $ catchMaybeIO nohardlink
	, do
		tmp <- fromRepo gitAnnexTmpDir
		createAnnexDirectory tmp
		eitherToMaybe <$> tryAnnexIO (go tmp)
	)
  where
	{- In indirect mode, the write bit is removed from the file as part
	 - of lock down to guard against further writes, and because objects
	 - in the annex have their write bit disabled anyway.
	 -
	 - Freezing the content early also lets us fail early when
	 - someone else owns the file.
	 -
	 - This is not done in direct mode, because files there need to
	 - remain writable at all times.
	-}
  	go tmp = do
		unlessM isDirect $
			freezeContent file
		liftIO $ do
			(tmpfile, h) <- openTempFile tmp $
				relatedTemplate $ takeFileName file
			hClose h
			nukeFile tmpfile
			withhardlink tmpfile `catchIO` const nohardlink
  	nohardlink = do
		cache <- genInodeCache file
		return KeySource
			{ keyFilename = file
			, contentLocation = file
			, inodeCache = cache
			}
	withhardlink tmpfile = do
		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, Maybe InodeCache)
ingest Nothing = return (Nothing, Nothing)
ingest (Just source) = do
	backend <- chooseBackend $ keyFilename source
	k <- genKey source backend
	cache <- liftIO $ genInodeCache $ contentLocation source
	case (cache, inodeCache source) of
		(_, Nothing) -> go k cache
		(Just newc, Just c) | compareStrong c newc -> go k cache
		_ -> failure "changed while it was being added"
  where
	go k cache = ifM isDirect ( godirect k cache , goindirect k cache )

	goindirect (Just (key, _)) mcache = do
		catchAnnex (moveAnnex key $ contentLocation source)
			(undo (keyFilename source) key)
		liftIO $ nukeFile $ keyFilename source
		return $ (Just key, mcache)
	goindirect Nothing _ = failure "failed to generate a key"

	godirect (Just (key, _)) (Just cache) = do
		addInodeCache key cache
		finishIngestDirect key source
		return $ (Just key, Just cache)
	godirect _ _ = failure "failed to generate a key"

	failure msg = do
		warning $ keyFilename source ++ " " ++ msg
		when (contentLocation source /= keyFilename source) $
			liftIO $ nukeFile $ contentLocation source
		return (Nothing, Nothing)

finishIngestDirect :: Key -> KeySource -> Annex ()
finishIngestDirect key source = do
	void $ addAssociatedFile key $ keyFilename source
	when (contentLocation source /= keyFilename source) $
		liftIO $ nukeFile $ contentLocation source

	{- Copy to any other locations using the same key. -}
	otherfs <- filter (/= keyFilename source) <$> associatedFiles key
	forM_ otherfs $
		addContentWhenNotPresent key (keyFilename source)

perform :: FilePath -> CommandPerform
perform file = lockDown file >>= ingest >>= go
  where
  	go (Just key, cache) = next $ cleanup file key cache True
	go (Nothing, _) = stop

{- 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
		catchAnnex (fromAnnex key file) tryharder
		logStatus key InfoMissing
	throwAnnex e
  where
	-- fromAnnex could fail if the file ownership is weird
	tryharder :: IOException -> Annex ()
	tryharder _ = do
		src <- calcRepo $ gitAnnexLocation key
		liftIO $ moveFile src file

{- Creates the symlink to the annexed content, returns the link target. -}
link :: FilePath -> Key -> Maybe InodeCache -> Annex String
link file key mcache = flip catchAnnex (undo file key) $ do
	l <- inRepo $ gitAnnexLink file key
	replaceFile file $ makeAnnexLink l

#ifdef WITH_CLIBS
#ifndef __ANDROID__
	-- touch symlink to have same time as the original file,
	-- as provided in the InodeCache
	case mcache of
		Just c -> liftIO $ touch file (TimeSpec $ inodeCacheToMtime c) False
		Nothing -> noop
#endif
#endif

	return l

{- Creates the symlink to the annexed content, and stages it in git.
 -
 - 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.
 -}
addLink :: FilePath -> Key -> Maybe InodeCache -> Annex ()
addLink file key mcache = ifM (coreSymlinks <$> Annex.getGitConfig)
	( do
		_ <- link file key mcache
		params <- ifM (Annex.getState Annex.force)
			( return [Param "-f"]
			, return []
			)
		Annex.Queue.addCommand "add" (params++[Param "--"]) [file]
	, do
		l <- link file key mcache
		addAnnexLink l file
	)

cleanup :: FilePath -> Key -> Maybe InodeCache -> Bool -> CommandCleanup
cleanup file key mcache hascontent = do
	ifM (isDirect <&&> pure hascontent)
		( do
			l <- inRepo $ gitAnnexLink file key
			stageSymlink file =<< hashSymlink l
		, addLink file key mcache
		)
	when hascontent $
		logStatus key InfoPresent
	return True