{- git-annex v1 -> v2 upgrade support
 -
 - Copyright 2011 Joey Hess <joey@kitenet.net>
 -
 - Licensed under the GNU GPL version 3 or higher.
 -}

module Upgrade.V1 where

import System.IO.Error (try)
import System.Directory
import Control.Monad.State (liftIO)
import Control.Monad (filterM, forM_, unless)
import System.Posix.Files
import System.FilePath
import Data.String.Utils
import System.Posix.Types
import Data.Maybe
import Data.Char

import Types.Key
import Content
import Types
import Locations
import LocationLog
import qualified Annex
import qualified AnnexQueue
import qualified Git
import qualified Git.LsFiles as LsFiles
import Backend
import Messages
import Version
import Utility
import qualified Upgrade.V2

-- v2 adds hashing of filenames of content and location log files.
-- Key information is encoded in filenames differently, so
-- both content and location log files move around, and symlinks
-- to content need to be changed.
-- 
-- When upgrading a v1 key to v2, file size metadata ought to be
-- added to the key (unless it is a WORM key, which encoded
-- mtime:size in v1). This can only be done when the file content
-- is present. Since upgrades need to happen consistently, 
-- (so that two repos get changed the same way by the upgrade, and
-- will merge), that metadata cannot be added on upgrade.
--
-- Note that file size metadata
-- will only be used for detecting situations where git-annex
-- would run out of disk space, so if some keys don't have it,
-- the impact is minor. At least initially. It could be used in the
-- future by smart auto-repo balancing code, etc.
--
-- Anyway, since v2 plans ahead for other metadata being included
-- in keys, there should probably be a way to update a key.
-- Something similar to the migrate subcommand could be used,
-- and users could then run that at their leisure.

upgrade :: Annex Bool
upgrade = do
	showNote "v1 to v2"

	g <- Annex.gitRepo
	if Git.repoIsLocalBare g
		then do
			moveContent
			setVersion
		else do
			moveContent
			updateSymlinks
			moveLocationLogs
	
			AnnexQueue.flush True
			setVersion
	
	Upgrade.V2.upgrade

moveContent :: Annex ()
moveContent = do
	showNote "moving content..."
	files <- getKeyFilesPresent1
	forM_ files move
	where
		move f = do
			let k = fileKey1 (takeFileName f)
			let d = parentDir f
			liftIO $ allowWrite d
			liftIO $ allowWrite f
			moveAnnex k f
			liftIO $ removeDirectory d

updateSymlinks :: Annex ()
updateSymlinks = do
	showNote "updating symlinks..."
	g <- Annex.gitRepo
	files <- liftIO $ LsFiles.inRepo g [Git.workTree g]
	forM_ files $ fixlink
	where
		fixlink f = do
			r <- lookupFile1 f
			case r of
				Nothing -> return ()
				Just (k, _) -> do
					link <- calcGitLink f k
					liftIO $ removeFile f
					liftIO $ createSymbolicLink link f
					AnnexQueue.add "add" [Param "--"] f

moveLocationLogs :: Annex ()
moveLocationLogs = do
	showNote "moving location logs..."
	logkeys <- oldlocationlogs
	forM_ logkeys move
		where
			oldlocationlogs = do
				g <- Annex.gitRepo
				let dir = Upgrade.V2.gitStateDir g
				exists <- liftIO $ doesDirectoryExist dir
				if exists
					then do
						contents <- liftIO $ getDirectoryContents dir
						return $ catMaybes $ map oldlog2key contents
					else return []
			move (l, k) = do
				g <- Annex.gitRepo
				let dest = logFile k
				let dir = Upgrade.V2.gitStateDir g
				let f = dir </> l
				liftIO $ createDirectoryIfMissing True (parentDir dest)
				-- could just git mv, but this way deals with
				-- log files that are not checked into git,
				-- as well as merging with already upgraded
				-- logs that have been pulled from elsewhere
				old <- readLog f
				new <- readLog dest
				writeLog dest (old++new)
				AnnexQueue.add "add" [Param "--"] dest
				AnnexQueue.add "add" [Param "--"] f
				AnnexQueue.add "rm" [Param "--quiet", Param "-f", Param "--"] f
		
oldlog2key :: FilePath -> Maybe (FilePath, Key)
oldlog2key l = 
	let len = length l - 4 in
		if drop len l == ".log"
		then let k = readKey1 (take len l) in
			if null (keyName k) || null (keyBackendName k)
			then Nothing
			else Just (l, k)
		else Nothing

-- WORM backend keys: "WORM:mtime:size:filename"
-- all the rest: "backend:key"
--
-- If the file looks like "WORM:XXX-...", then it was created by mixing
-- v2 and v1; that infelicity is worked around by treating the value
-- as the v2 key that it is.
readKey1 :: String -> Key
readKey1 v = 
	if mixup
		then fromJust $ readKey $ join ":" $ tail bits
		else Key { keyName = n , keyBackendName = b, keySize = s, keyMtime = t }
	where
		bits = split ":" v
		b = head bits
		n = join ":" $ drop (if wormy then 3 else 1) bits
		t = if wormy
			then Just (read (bits !! 1) :: EpochTime)
			else Nothing
		s = if wormy
			then Just (read (bits !! 2) :: Integer)
			else Nothing
		wormy = head bits == "WORM"
		mixup = wormy && (isUpper $ head $ bits !! 1)

showKey1 :: Key -> String
showKey1 Key { keyName = n , keyBackendName = b, keySize = s, keyMtime = t } =
	join ":" $ filter (not . null) [b, showifhere t, showifhere s, n]
		where
			showifhere Nothing = ""
			showifhere (Just v) = show v

keyFile1 :: Key -> FilePath
keyFile1 key = replace "/" "%" $ replace "%" "&s" $ replace "&" "&a"  $ showKey1 key

fileKey1 :: FilePath -> Key
fileKey1 file = readKey1 $
	replace "&a" "&" $ replace "&s" "%" $ replace "%" "/" file

logFile1 :: Git.Repo -> Key -> String
logFile1 repo key = Upgrade.V2.gitStateDir repo ++ keyFile1 key ++ ".log"

lookupFile1 :: FilePath -> Annex (Maybe (Key, Backend Annex))
lookupFile1 file = do
	tl <- liftIO $ try getsymlink
	case tl of
		Left _ -> return Nothing
		Right l -> makekey l
	where
		getsymlink = do
			l <- readSymbolicLink file
			return $ takeFileName l
		makekey l = do
			case maybeLookupBackendName bname of
				Nothing -> do
					unless (null kname || null bname ||
					        not (isLinkToAnnex l)) $
						warning skip
					return Nothing
				Just backend -> return $ Just (k, backend)
			where
				k = fileKey1 l
				bname = keyBackendName k
				kname = keyName k
				skip = "skipping " ++ file ++ 
					" (unknown backend " ++ bname ++ ")"

getKeyFilesPresent1 :: Annex [FilePath]
getKeyFilesPresent1  = do
	g <- Annex.gitRepo
	getKeyFilesPresent1' $ gitAnnexObjectDir g
getKeyFilesPresent1' :: FilePath -> Annex [FilePath]
getKeyFilesPresent1' dir = do
	exists <- liftIO $ doesDirectoryExist dir
	if (not exists)
		then return []
		else do
			dirs <- liftIO $ getDirectoryContents dir
			let files = map (\d -> dir ++ "/" ++ d ++ "/" ++ takeFileName d) dirs
			liftIO $ filterM present files
	where
		present f = do
			result <- try $ getFileStatus f
			case result of
				Right s -> return $ isRegularFile s
				Left _ -> return False