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

module Remote (
	Remote,
	uuid,
	name,
	storeKey,
	retrieveKeyFile,
	removeKey,
	hasKey,
	hasKeyCheap,

	byName,
	nameToUUID,
	keyPossibilities,
	remotesWithUUID,
	remotesWithoutUUID
) where

import Control.Monad.State (liftIO)
import Control.Monad (when, liftM)
import Data.List
import Data.String.Utils

import RemoteClass
import qualified Remote.Git
import qualified Remote.S3
import Types
import UUID
import qualified Annex
import Trust
import LocationLog
import Messages

{- Add generators for new Remotes here. -}
generators :: [Annex (RemoteGenerator Annex)]
generators =
	[ Remote.Git.generate
	, Remote.S3.generate
	]

{- Runs a list of generators. -}
runGenerators :: [Annex (RemoteGenerator Annex)] -> Annex [Remote Annex]
runGenerators gs = do
	(actions, expensive) <- collect ([], []) gs
	when (not $ null expensive) $
		showNote $ "getting UUID for " ++ join ", " expensive
	sequence actions
	where
		collect v [] = return v
		collect (actions, expensive) (x:xs) = do
			(a, e) <- x
			collect (a++actions, e++expensive) xs

{- Builds a list of all available Remotes.
 - Since doing so can be expensive, the list is cached in the Annex. -}
genList :: Annex [Remote Annex]
genList = do
	rs <- Annex.getState Annex.remotes
	if null rs
		then do
			rs' <- runGenerators generators
			Annex.changeState $ \s -> s { Annex.remotes = rs' }
			return rs'
		else return rs

{- Looks up a remote by name. (Or by UUID.) -}
byName :: String -> Annex (Remote Annex)
byName "" = error "no remote specified"
byName n = do
	allremotes <- genList
	let match = filter matching allremotes
	when (null match) $ error $
		"there is no git remote named \"" ++ n ++ "\""
	return $ head match
	where
		matching r = n == name r || n == uuid r

{- Looks up a remote by name (or by UUID), and returns its UUID. -}
nameToUUID :: String -> Annex UUID
nameToUUID "." = do -- special case for current repo
	g <- Annex.gitRepo
	getUUID g
nameToUUID n = liftM uuid (byName n)

{- Cost ordered lists of remotes that the LocationLog indicate may have a key.
 -
 - Also returns a list of UUIDs that are trusted to have the key
 - (some may not have configured remotes).
 -}
keyPossibilities :: Key -> Annex ([Remote Annex], [UUID])
keyPossibilities key = do
	g <- Annex.gitRepo
	u <- getUUID g
	trusted <- trustGet Trusted

	-- get uuids of all remotes that are recorded to have the key
	uuids <- liftIO $ keyLocations g key
	let validuuids = filter (/= u) uuids

	-- note that validuuids is assumed to not have dups
	let validtrusteduuids = intersect validuuids trusted

	-- remotes that match uuids that have the key
	allremotes <- genList
	let validremotes = remotesWithUUID allremotes validuuids

	return (sort validremotes, validtrusteduuids)

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