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

module Remote (
	Remote,
	uuid,
	name,
	storeKey,
	retrieveKeyFile,
	retrieveKeyFileCheap,
	removeKey,
	hasKey,
	hasKeyCheap,
	whereisKey,
	remoteFsck,

	remoteTypes,
	remoteList,
	remoteList',
	gitSyncableRemote,
	remoteMap,
	remoteMap',
	uuidDescriptions,
	addName,
	byName,
	byName',
	byNameOrGroup,
	byNameOnly,
	byNameWithUUID,
	byUUID,
	byCost,
	prettyPrintUUIDs,
	prettyPrintUUIDsDescs,
	prettyPrintUUIDsWith,
	prettyListUUIDs,
	prettyUUID,
	remoteFromUUID,
	remotesWithUUID,
	remotesWithoutUUID,
	keyLocations,
	keyPossibilities,
	remoteLocations,
	nameToUUID,
	nameToUUID',
	showTriedRemotes,
	showLocations,
	forceTrust,
	logStatus,
	checkAvailable,
	claimingUrl,
	isExportSupported,
) where

import Data.Ord
import qualified Data.Map as M
import qualified Data.Vector as V

import Annex.Common
import Types.Remote
import qualified Annex
import Annex.UUID
import Logs.UUID
import Logs.Trust
import Logs.Location hiding (logStatus)
import Logs.Web
import Remote.List
import Config
import Config.DynamicConfig
import Git.Types (RemoteName)
import Utility.Aeson

{- Map from UUIDs of Remotes to a calculated value. -}
remoteMap :: (Remote -> v) -> Annex (M.Map UUID v)
remoteMap mkv = remoteMap' mkv (pure . mkk)
  where
	mkk r = case uuid r of
		NoUUID -> Nothing
		u -> Just u

remoteMap' :: Ord k => (Remote -> v) -> (Remote -> Annex (Maybe k)) -> Annex (M.Map k v)
remoteMap' mkv mkk = M.fromList . catMaybes <$> (mapM mk =<< remoteList)
  where
	mk r = mkk r >>= return . \case
		Nothing -> Nothing
		Just k -> Just (k, mkv r)

{- Map of UUIDs of repositories and their descriptions.
 - The names of Remotes are added to suppliment any description that has
 - been set for a repository.  -}
uuidDescriptions :: Annex (M.Map UUID String)
uuidDescriptions = M.unionWith addName <$> uuidMap <*> remoteMap name

addName :: String -> RemoteName -> String
addName desc n
	| desc == n || null desc = "[" ++ n ++ "]"
	| otherwise = desc ++ " [" ++ n ++ "]"

byUUID :: UUID -> Annex (Maybe Remote)
byUUID u = headMaybe . filter matching <$> remoteList
  where
	matching r = uuid r == u

{- When a name is specified, looks up the remote matching that name.
 - (Or it can be a UUID.)
 -
 - Throws an error if a name is specified and no matching remote can be
 - found.
 -}
byName :: Maybe RemoteName -> Annex (Maybe Remote)
byName Nothing = return Nothing
byName (Just n) = either giveup Just <$> byName' n

{- Like byName, but the remote must have a configured UUID. -}
byNameWithUUID :: Maybe RemoteName -> Annex (Maybe Remote)
byNameWithUUID = checkuuid <=< byName
  where
	checkuuid Nothing = return Nothing
	checkuuid (Just r)
		| uuid r == NoUUID = do
			repo <- getRepo r
			ifM (liftIO $ getDynamicConfig $ remoteAnnexIgnore (gitconfig r))
				( giveup $ noRemoteUUIDMsg r ++
					" (" ++ show (remoteConfig repo "ignore") ++
					" is set)"
				, giveup $ noRemoteUUIDMsg r
				)
		| otherwise = return $ Just r

byName' :: RemoteName -> Annex (Either String Remote)
byName' "" = return $ Left "no remote specified"
byName' n = go . filter matching <$> remoteList
  where
	go [] = Left $ "there is no available git remote named \"" ++ n ++ "\""
	go (match:_) = Right match
	matching r = n == name r || toUUID n == uuid r

{- Finds the remote or remote group matching the name. -}
byNameOrGroup :: RemoteName -> Annex [Remote]
byNameOrGroup n = go =<< getConfigMaybe (ConfigKey ("remotes." ++ n))
  where
	go (Just l) = catMaybes <$> mapM (byName . Just) (splitc ' ' l)
	go Nothing = maybeToList <$> byName (Just n)

{- Only matches remote name, not UUID -}
byNameOnly :: RemoteName -> Annex (Maybe Remote)
byNameOnly n = headMaybe . filter matching <$> remoteList
  where
	matching r = n == name r

noRemoteUUIDMsg :: Remote -> String
noRemoteUUIDMsg r = "cannot determine uuid for " ++ name r ++ " (perhaps you need to run \"git annex sync\"?)"

{- Looks up a remote by name (or by UUID, or even by description),
 - and returns its UUID. Finds even repositories that are not
 - configured in .git/config. -}
nameToUUID :: RemoteName -> Annex UUID
nameToUUID = either giveup return <=< nameToUUID'

nameToUUID' :: RemoteName -> Annex (Either String UUID)
nameToUUID' "." = Right <$> getUUID -- special case for current repo
nameToUUID' "here" = Right <$> getUUID
nameToUUID' n = byName' n >>= go
  where
	go (Right r) = return $ case uuid r of
		NoUUID -> Left $ noRemoteUUIDMsg r
		u -> Right u
	go (Left e) = do
		m <- uuidMap
		return $ case M.keys (M.filter (== n) m) of
			[u] -> Right u
			[] -> let u = toUUID n
				in case M.keys (M.filterWithKey (\k _ -> k == u) m) of
					[] -> Left e
					_ -> Right u
			_us -> Left "Found multiple repositories with that description"

{- Pretty-prints a list of UUIDs of remotes, with their descriptions,
 - for human display.
 -
 - When JSON is enabled, also outputs a machine-readable description
 - of the UUIDs. -}
prettyPrintUUIDs :: String -> [UUID] -> Annex String
prettyPrintUUIDs header uuids = do
	descm <- uuidDescriptions
	prettyPrintUUIDsDescs header descm uuids

prettyPrintUUIDsDescs :: String -> M.Map UUID RemoteName -> [UUID] -> Annex String
prettyPrintUUIDsDescs header descm uuids =
	prettyPrintUUIDsWith Nothing header descm
		(const Nothing)
		(zip uuids (repeat (Nothing :: Maybe String)))

{- An optional field can be included in the list of UUIDs. -}
prettyPrintUUIDsWith
	:: ToJSON' v
	=> Maybe String 
	-> String 
	-> M.Map UUID RemoteName
	-> (v -> Maybe String)
	-> [(UUID, Maybe v)] 
	-> Annex String
prettyPrintUUIDsWith optfield header descm showval uuidvals = do
	hereu <- getUUID
	maybeShowJSON $ JSONChunk [(header, V.fromList $ map (jsonify hereu) uuidvals)]
	return $ unwords $ map (\u -> "\t" ++ prettify hereu u ++ "\n") uuidvals
  where
	finddescription u = M.findWithDefault "" u descm
	prettify hereu (u, optval)
		| not (null d) = addoptval $ fromUUID u ++ " -- " ++ d
		| otherwise = addoptval $ fromUUID u
	  where
		ishere = hereu == u
		n = finddescription u
		d
			| null n && ishere = "here"
			| ishere = addName n "here"
			| otherwise = n
		addoptval s = case showval =<< optval of
			Nothing -> s
			Just val -> val ++ ": " ++ s
	jsonify hereu (u, optval) = object $ catMaybes
		[ Just (packString "uuid", toJSON' $ fromUUID u)
		, Just (packString "description", toJSON' $ finddescription u)
		, Just (packString "here", toJSON' $ hereu == u)
		, case (optfield, optval) of
			(Just field, Just val) -> Just (packString field, toJSON' val)
			_ -> Nothing
		]

{- List of remote names and/or descriptions, for human display.  -}
prettyListUUIDs :: [UUID] -> Annex [String]
prettyListUUIDs uuids = do
	hereu <- getUUID
	m <- uuidDescriptions
	return $ map (prettify m hereu) uuids
  where
	finddescription m u = M.findWithDefault "" u m
	prettify m hereu u
		| u == hereu = addName n "here"
		| otherwise = n
	  where
		n = finddescription m u

{- Nice display of a remote's name and/or description. -}
prettyUUID :: UUID -> Annex String
prettyUUID u = concat <$> prettyListUUIDs [u]

{- Gets the remote associated with a UUID. -}
remoteFromUUID :: UUID -> Annex (Maybe Remote)
remoteFromUUID u = ifM ((==) u <$> getUUID)
	( return Nothing
	, maybe tryharder (return . Just) =<< findinmap
	)
  where
	findinmap = M.lookup u <$> remoteMap id
	{- Re-read remote list in case a new remote has popped up. -}
	tryharder = do
		void remoteListRefresh
		findinmap

{- Filters a list of remotes to ones that have the listed uuids. -}
remotesWithUUID :: [Remote] -> [UUID] -> [Remote]
remotesWithUUID rs us = filter (\r -> uuid r `elem` us) rs

{- Filters a list of remotes to ones that do not have the listed uuids. -}
remotesWithoutUUID :: [Remote] -> [UUID] -> [Remote]
remotesWithoutUUID rs us = filter (\r -> uuid r `notElem` us) rs

{- List of repository UUIDs that the location log indicates may have a key.
 - Dead repositories are excluded. -}
keyLocations :: Key -> Annex [UUID]
keyLocations key = trustExclude DeadTrusted =<< loggedLocations key

{- Cost ordered lists of remotes that the location log indicates
 - may have a key.
 -}
keyPossibilities :: Key -> Annex [Remote]
keyPossibilities key = do
	u <- getUUID
	-- uuids of all remotes that are recorded to have the key
	locations <- filter (/= u) <$> keyLocations key
	fst <$> remoteLocations locations []

{- Given a list of locations of a key, and a list of all
 - trusted repositories, generates a cost-ordered list of
 - remotes that contain the key, and a list of trusted locations of the key.
 -}
remoteLocations :: [UUID] -> [UUID] -> Annex ([Remote], [UUID])
remoteLocations locations trusted = do
	let validtrustedlocations = nub locations `intersect` trusted

	-- remotes that match uuids that have the key
	allremotes <- remoteList 
		>>= filterM (not <$$> liftIO . getDynamicConfig . remoteAnnexIgnore . gitconfig)
	let validremotes = remotesWithUUID allremotes locations

	return (sortBy (comparing cost) validremotes, validtrustedlocations)

{- Displays known locations of a key. -}
showLocations :: Bool -> Key -> [UUID] -> String -> Annex ()
showLocations separateuntrusted key exclude nolocmsg = do
	u <- getUUID
	uuids <- keyLocations key
	untrusteduuids <- if separateuntrusted
		then trustGet UnTrusted
		else pure []
	let uuidswanted = filteruuids uuids (u:exclude++untrusteduuids) 
	let uuidsskipped = filteruuids uuids (u:exclude++uuidswanted)
	ppuuidswanted <- prettyPrintUUIDs "wanted" uuidswanted
	ppuuidsskipped <- prettyPrintUUIDs "skipped" uuidsskipped
	let msg = message ppuuidswanted ppuuidsskipped
	unless (null msg) $
		showLongNote msg
	ignored <- remoteList
		>>= filterM (liftIO . getDynamicConfig . remoteAnnexIgnore . gitconfig)
	unless (null ignored) $
		showLongNote $ "(Note that these git remotes have annex-ignore set: " ++ unwords (map name ignored) ++ ")"
  where
	filteruuids l x = filter (`notElem` x) l
	message [] [] = nolocmsg
	message rs [] = "Try making some of these repositories available:\n" ++ rs
	message [] us = "Also these untrusted repositories may contain the file:\n" ++ us
	message rs us = message rs [] ++ message [] us

showTriedRemotes :: [Remote] -> Annex ()
showTriedRemotes [] = noop
showTriedRemotes remotes =
	showLongNote $ "Unable to access these remotes: " ++
		intercalate ", " (map name remotes)

forceTrust :: TrustLevel -> String -> Annex ()
forceTrust level remotename = do
	u <- nameToUUID remotename
	Annex.changeState $ \s ->
		s { Annex.forcetrust = M.insert u level (Annex.forcetrust s) }

{- Used to log a change in a remote's having a key. The change is logged
 - in the local repo, not on the remote. The process of transferring the
 - key to the remote, or removing the key from it *may* log the change
 - on the remote, but this cannot always be relied on. -}
logStatus :: Remote -> Key -> LogStatus -> Annex ()
logStatus remote key = logChange key (uuid remote)

{- Orders remotes by cost, with ones with the lowest cost grouped together. -}
byCost :: [Remote] -> [[Remote]]
byCost = map snd . sortBy (comparing fst) . M.toList . costmap
  where
	costmap = M.fromListWith (++) . map costpair
	costpair r = (cost r, [r])

checkAvailable :: Bool -> Remote -> IO Bool
checkAvailable assumenetworkavailable = 
	maybe (return assumenetworkavailable) doesDirectoryExist . localpath

hasKey :: Remote -> Key -> Annex (Either String Bool)
hasKey r k = either (Left  . show) Right <$> tryNonAsync (checkPresent r k)

hasKeyCheap :: Remote -> Bool
hasKeyCheap = checkPresentCheap

{- The web special remote claims urls by default. -}
claimingUrl :: URLString -> Annex Remote
claimingUrl url = do
	rs <- remoteList
	let web = Prelude.head $ filter (\r -> uuid r == webUUID) rs
	fromMaybe web <$> firstM checkclaim rs
  where
	checkclaim = maybe (pure False) (`id` url) . claimUrl