{- git-annex command seeking
 - 
 - These functions find appropriate files or other things based on
 - the values a user passes to a command, and prepare actions operating
 - on them.
 -
 - Copyright 2010-2012 Joey Hess <joey@kitenet.net>
 -
 - Licensed under the GNU GPL version 3 or higher.
 -}

module Seek where

import System.PosixCompat.Files

import Common.Annex
import Types.Command
import Types.Key
import qualified Annex
import qualified Git
import qualified Git.Command
import qualified Git.LsFiles as LsFiles
import qualified Limit
import qualified Option
import Config

seekHelper :: ([FilePath] -> Git.Repo -> IO ([FilePath], IO Bool)) -> [FilePath] -> Annex [FilePath]
seekHelper a params = do
	ll <- inRepo $ \g ->
		runSegmentPaths (\fs -> Git.Command.leaveZombie <$> a fs g) params
	{- Show warnings only for files/directories that do not exist. -}
	forM_ (map fst $ filter (null . snd) $ zip params ll) $ \p ->
		unlessM (isJust <$> liftIO (catchMaybeIO $ getSymbolicLinkStatus p)) $
			fileNotFound p
	return $ concat ll

withFilesInGit :: (FilePath -> CommandStart) -> CommandSeek
withFilesInGit a params = prepFiltered a $ seekHelper LsFiles.inRepo params

withFilesNotInGit :: (FilePath -> CommandStart) -> CommandSeek
withFilesNotInGit a params = do
	{- dotfiles are not acted on unless explicitly listed -}
	files <- filter (not . dotfile) <$>
		seekunless (null ps && not (null params)) ps
	dotfiles <- seekunless (null dotps) dotps
	prepFiltered a $ return $ concat $ segmentPaths params (files++dotfiles)
  where
	(dotps, ps) = partition dotfile params
	seekunless True _ = return []
	seekunless _ l = do
		force <- Annex.getState Annex.force
		g <- gitRepo
		liftIO $ Git.Command.leaveZombie <$> LsFiles.notInRepo force l g

withPathContents :: ((FilePath, FilePath) -> CommandStart) -> CommandSeek
withPathContents a params = map a . concat <$> liftIO (mapM get params)
  where
	get p = ifM (isDirectory <$> getFileStatus p)
		( map (\f -> (f, makeRelative p f)) <$> dirContentsRecursive p
		, return [(p, takeFileName p)]
		)

withWords :: ([String] -> CommandStart) -> CommandSeek
withWords a params = return [a params]

withStrings :: (String -> CommandStart) -> CommandSeek
withStrings a params = return $ map a params

withPairs :: ((String, String) -> CommandStart) -> CommandSeek
withPairs a params = return $ map a $ pairs [] params
  where
	pairs c [] = reverse c
	pairs c (x:y:xs) = pairs ((x,y):c) xs
	pairs _ _ = error "expected pairs"

withFilesToBeCommitted :: (String -> CommandStart) -> CommandSeek
withFilesToBeCommitted a params = prepFiltered a $
	seekHelper LsFiles.stagedNotDeleted params

withFilesUnlocked :: (FilePath -> CommandStart) -> CommandSeek
withFilesUnlocked = withFilesUnlocked' LsFiles.typeChanged

withFilesUnlockedToBeCommitted :: (FilePath -> CommandStart) -> CommandSeek
withFilesUnlockedToBeCommitted = withFilesUnlocked' LsFiles.typeChangedStaged

withFilesUnlocked' :: ([FilePath] -> Git.Repo -> IO ([FilePath], IO Bool)) -> (FilePath -> CommandStart) -> CommandSeek
withFilesUnlocked' typechanged a params = do
	-- unlocked files have changed type from a symlink to a regular file
	typechangedfiles <- seekHelper typechanged params
	let unlockedfiles = liftIO $ filterM notSymlink typechangedfiles
	prepFiltered a unlockedfiles

{- Finds files that may be modified. -}
withFilesMaybeModified :: (FilePath -> CommandStart) -> CommandSeek
withFilesMaybeModified a params =
	prepFiltered a $ seekHelper LsFiles.modified params

withKeys :: (Key -> CommandStart) -> CommandSeek
withKeys a params = return $ map (a . parse) params
  where
	parse p = fromMaybe (error "bad key") $ file2key p

withValue :: Annex v -> (v -> CommandSeek) -> CommandSeek
withValue v a params = do
	r <- v
	a r params

{- Modifies a seek action using the value of a field option, which is fed into
 - a conversion function, and then is passed into the seek action.
 - This ensures that the conversion function only runs once.
 -}
withField :: Option -> (Maybe String -> Annex a) -> (a -> CommandSeek) -> CommandSeek
withField option converter = withValue $
	converter <=< Annex.getField $ Option.name option

withFlag :: Option -> (Bool -> CommandSeek) -> CommandSeek
withFlag option = withValue $ Annex.getFlag (Option.name option)

withNothing :: CommandStart -> CommandSeek
withNothing a [] = return [a]
withNothing _ _ = error "This command takes no parameters."


prepFiltered :: (FilePath -> CommandStart) -> Annex [FilePath] -> Annex [CommandStart]
prepFiltered a fs = do
	matcher <- Limit.getMatcher
	map (process matcher) <$> fs
  where
	process matcher f = ifM (matcher $ Annex.FileInfo f f)
		( a f , return Nothing )

notSymlink :: FilePath -> IO Bool
notSymlink f = liftIO $ not . isSymbolicLink <$> getSymbolicLinkStatus f

whenNotDirect :: CommandSeek -> CommandSeek
whenNotDirect a params = ifM isDirect ( return [] , a params )

whenDirect :: CommandSeek -> CommandSeek
whenDirect a params = ifM isDirect ( a params, return [] )