{- Web url logs.
 -
 - Copyright 2011-2014 Joey Hess <id@joeyh.name>
 -
 - Licensed under the GNU GPL version 3 or higher.
 -}

module Logs.Web (
	URLString,
	getUrls,
	getUrlsWithPrefix,
	setUrlPresent,
	setUrlMissing,
	knownUrls,
	Downloader(..),
	getDownloader,
	setDownloader,
	setDownloader',
	setTempUrl,
	removeTempUrl,
) where

import qualified Data.ByteString.Lazy.Char8 as L
import qualified Data.Map as M

import Annex.Common
import qualified Annex
import Logs
import Logs.Presence
import Logs.Location
import qualified Annex.Branch
import Annex.CatFile
import qualified Git
import qualified Git.LsFiles
import Utility.Url
import Annex.UUID
import qualified Types.Remote as Remote

{- Gets all urls that a key might be available from. -}
getUrls :: Key -> Annex [URLString]
getUrls key = do
	config <- Annex.getGitConfig
	l <- go $ urlLogFile config key : oldurlLogs config key
	tmpl <- Annex.getState (maybeToList . M.lookup key . Annex.tempurls)
	return (tmpl ++ l)
  where
	go [] = return []
	go (l:ls) = do
		us <- currentLogInfo l
		if null us
			then go ls
			else return us

getUrlsWithPrefix :: Key -> String -> Annex [URLString]
getUrlsWithPrefix key prefix = filter (prefix `isPrefixOf`) 
	. map (fst . getDownloader)
	<$> getUrls key

setUrlPresent :: UUID -> Key -> URLString -> Annex ()
setUrlPresent uuid key url = do
	us <- getUrls key
	unless (url `elem` us) $ do
		config <- Annex.getGitConfig
		addLog (urlLogFile config key) =<< logNow InfoPresent url
	logChange key uuid InfoPresent

setUrlMissing :: UUID -> Key -> URLString -> Annex ()
setUrlMissing uuid key url = do
	config <- Annex.getGitConfig
	addLog (urlLogFile config key) =<< logNow InfoMissing url
	whenM (null <$> getUrls key) $
		logChange key uuid InfoMissing

{- Finds all known urls. -}
knownUrls :: Annex [(Key, URLString)]
knownUrls = do
	{- Ensure the git-annex branch's index file is up-to-date and
	 - any journaled changes are reflected in it, since we're going
	 - to query its index directly. -}
	Annex.Branch.update
	Annex.Branch.commit "update"
	Annex.Branch.withIndex $ do
		top <- fromRepo Git.repoPath
		(l, cleanup) <- inRepo $ Git.LsFiles.stagedDetails [top]
		r <- mapM getkeyurls l
		void $ liftIO cleanup
		return $ concat r
  where
	getkeyurls (f, s, _) = case urlLogFileKey f of
		Just k -> zip (repeat k) <$> geturls s
		Nothing -> return []
	geturls Nothing = return []
	geturls (Just logsha) = getLog . L.unpack <$> catObject logsha

setTempUrl :: Key -> URLString -> Annex ()
setTempUrl key url = Annex.changeState $ \s ->
	s { Annex.tempurls = M.insert key url (Annex.tempurls s) }

removeTempUrl :: Key -> Annex ()
removeTempUrl key = Annex.changeState $ \s ->
	s { Annex.tempurls = M.delete key (Annex.tempurls s) }

data Downloader = WebDownloader | QuviDownloader | OtherDownloader
	deriving (Eq, Show)

{- To keep track of how an url is downloaded, it's mangled slightly in
 - the log. For quvi, "quvi:" is prefixed. For urls that are handled by
 - some other remote, ":" is prefixed. -}
setDownloader :: URLString -> Downloader -> String
setDownloader u WebDownloader = u
setDownloader u QuviDownloader = "quvi:" ++ u
setDownloader u OtherDownloader = ":" ++ u

setDownloader' :: URLString -> Remote -> String
setDownloader' u r
	| Remote.uuid r == webUUID = setDownloader u WebDownloader
	| otherwise = setDownloader u OtherDownloader

getDownloader :: URLString -> (URLString, Downloader)
getDownloader u = case separate (== ':') u of
	("quvi", u') -> (u', QuviDownloader)
	("", u') -> (u', OtherDownloader)
	_ -> (u, WebDownloader)