{- git-annex repository initialization
 -
 - Copyright 2011-2016 Joey Hess <id@joeyh.name>
 -
 - Licensed under the GNU GPL version 3 or higher.
 -}

{-# LANGUAGE CPP #-}

module Annex.Init (
	ensureInitialized,
	isInitialized,
	initialize,
	initialize',
	uninitialize,
	probeCrippledFileSystem,
	probeCrippledFileSystem',
) where

import Annex.Common
import qualified Annex
import qualified Git
import qualified Git.LsFiles
import qualified Git.Config
import qualified Git.Objects
import qualified Annex.Branch
import Logs.UUID
import Logs.Trust.Basic
import Types.TrustLevel
import Annex.Version
import Annex.Difference
import Annex.UUID
import Annex.Link
import Config
import Annex.Direct
import Annex.AdjustedBranch
import Annex.Environment
import Annex.Hook
import Annex.InodeSentinal
import Upgrade
import Annex.Perms
import qualified Database.Keys
#ifndef mingw32_HOST_OS
import Utility.UserInfo
import Utility.FileMode
import System.Posix.User
import qualified Utility.LockFile.Posix as Posix
#endif

genDescription :: Maybe String -> Annex String
genDescription (Just d) = return d
genDescription Nothing = do
	reldir <- liftIO . relHome =<< liftIO . absPath =<< fromRepo Git.repoPath
	hostname <- fromMaybe "" <$> liftIO getHostname
#ifndef mingw32_HOST_OS
	let at = if null hostname then "" else "@"
	username <- liftIO myUserName
	return $ concat [username, at, hostname, ":", reldir]
#else
	return $ concat [hostname, ":", reldir]
#endif

initialize :: Maybe String -> Maybe Version -> Annex ()
initialize mdescription mversion = do
	{- Has to come before any commits are made as the shared
	 - clone heuristic expects no local objects. -}
	sharedclone <- checkSharedClone

	{- This will make the first commit to git, so ensure git is set up
	 - properly to allow commits when running it. -}
	ensureCommit $ Annex.Branch.create

	prepUUID
	initialize' mversion
	
	initSharedClone sharedclone

	u <- getUUID
	describeUUID u =<< genDescription mdescription

-- Everything except for uuid setup, shared clone setup, and initial
-- description.
initialize' :: Maybe Version -> Annex ()
initialize' mversion = do
	checkLockSupport
	checkFifoSupport
	checkCrippledFileSystem
	unlessM isBare $
		hookWrite preCommitHook
	setDifferences
	unlessM (isJust <$> getVersion) $
		setVersion (fromMaybe defaultVersion mversion)
	whenM versionSupportsUnlockedPointers $ do
		configureSmudgeFilter
		Database.Keys.scanAssociatedFiles
	ifM (crippledFileSystem <&&> (not <$> isBare))
		( ifM versionSupportsUnlockedPointers
			( adjustToCrippledFileSystem
			, do
				enableDirectMode
				setDirect True
			)
		-- Handle case where this repo was cloned from a
		-- direct mode repo
		, unlessM isBare
			switchHEADBack
		)
	checkAdjustedClone
	createInodeSentinalFile False

uninitialize :: Annex ()
uninitialize = do
	hookUnWrite preCommitHook
	removeRepoUUID
	removeVersion

{- Will automatically initialize if there is already a git-annex
 - branch from somewhere. Otherwise, require a manual init
 - to avoid git-annex accidentially being run in git
 - repos that did not intend to use it.
 -
 - Checks repository version and handles upgrades too.
 -}
ensureInitialized :: Annex ()
ensureInitialized = getVersion >>= maybe needsinit checkUpgrade
  where
	needsinit = ifM Annex.Branch.hasSibling
			( initialize Nothing Nothing
			, error "First run: git-annex init"
			)

{- Checks if a repository is initialized. Does not check version for ugrade. -}
isInitialized :: Annex Bool
isInitialized = maybe Annex.Branch.hasSibling (const $ return True) =<< getVersion

isBare :: Annex Bool
isBare = fromRepo Git.repoIsLocalBare

{- A crippled filesystem is one that does not allow making symlinks,
 - or removing write access from files. -}
probeCrippledFileSystem :: Annex Bool
probeCrippledFileSystem = do
	tmp <- fromRepo gitAnnexTmpMiscDir
	createAnnexDirectory tmp
	liftIO $ probeCrippledFileSystem' tmp

probeCrippledFileSystem' :: FilePath -> IO Bool
probeCrippledFileSystem' tmp = do
#ifdef mingw32_HOST_OS
	return True
#else
	let f = tmp </> "gaprobe"
	writeFile f ""
	uncrippled <- probe f
	void $ tryIO $ allowWrite f
	removeFile f
	return $ not uncrippled
  where
	probe f = catchBoolIO $ do
		let f2 = f ++ "2"
		nukeFile f2
		createSymbolicLink f f2
		nukeFile f2
		preventWrite f
		-- Should be unable to write to the file, unless
		-- running as root, but some crippled
		-- filesystems ignore write bit removals.
		ifM ((== 0) <$> getRealUserID)
			( return True
			, not <$> catchBoolIO (writeFile f "2" >> return True)
			)
#endif

checkCrippledFileSystem :: Annex ()
checkCrippledFileSystem = whenM probeCrippledFileSystem $ do
	warning "Detected a crippled filesystem."
	setCrippledFileSystem True

	{- Normally git disables core.symlinks itself when the
	 - filesystem does not support them, but in Cygwin, git
	 - does support symlinks, while git-annex, not linking
	 - with Cygwin, does not. -}
	whenM (coreSymlinks <$> Annex.getGitConfig) $ do
		warning "Disabling core.symlinks."
		setConfig (ConfigKey "core.symlinks")
			(Git.Config.boolConfig False)

probeLockSupport :: Annex Bool
probeLockSupport = do
#ifdef mingw32_HOST_OS
	return True
#else
	tmp <- fromRepo gitAnnexTmpMiscDir
	let f = tmp </> "lockprobe"
	createAnnexDirectory tmp
	mode <- annexFileMode
	liftIO $ do
		nukeFile f
		ok <- catchBoolIO $ do
			Posix.dropLock =<< Posix.lockExclusive (Just mode) f
			return True
		nukeFile f
		return ok
#endif

probeFifoSupport :: Annex Bool
probeFifoSupport = do
#ifdef mingw32_HOST_OS
	return False
#else
	tmp <- fromRepo gitAnnexTmpMiscDir
	let f = tmp </> "gaprobe"
	let f2 = tmp </> "gaprobe2"
	createAnnexDirectory tmp
	liftIO $ do
		nukeFile f
		nukeFile f2
		ms <- tryIO $ do
			createNamedPipe f ownerReadMode
			createLink f f2
			getFileStatus f
		nukeFile f
		nukeFile f2
		return $ either (const False) isNamedPipe ms
#endif

checkLockSupport :: Annex ()
checkLockSupport = unlessM probeLockSupport $ do
	warning "Detected a filesystem without POSIX fcntl lock support."
	warning "Enabling annex.pidlock."
	setConfig (annexConfig "pidlock") (Git.Config.boolConfig True)

checkFifoSupport :: Annex ()
checkFifoSupport = unlessM probeFifoSupport $ do
	warning "Detected a filesystem without fifo support."
	warning "Disabling ssh connection caching."
	setConfig (annexConfig "sshcaching") (Git.Config.boolConfig False)

enableDirectMode :: Annex ()
enableDirectMode = unlessM isDirect $ do
	warning "Enabling direct mode."
	top <- fromRepo Git.repoPath
	(l, clean) <- inRepo $ Git.LsFiles.inRepo [top]
	forM_ l $ \f ->
		maybe noop (`toDirect` f) =<< isAnnexLink f
	void $ liftIO clean

checkSharedClone :: Annex Bool
checkSharedClone = inRepo Git.Objects.isSharedClone

initSharedClone :: Bool -> Annex ()
initSharedClone False = return ()
initSharedClone True = do
	showLongNote "Repository was cloned with --shared; setting annex.hardlink=true and making repository untrusted."
	u <- getUUID
	trustSet u UnTrusted
	setConfig (annexConfig "hardlink") (Git.Config.boolConfig True)
