{- git-annex assistant repository repair
 -
 - Copyright 2013 Joey Hess <joey@kitenet.net>
 -
 - Licensed under the GNU AGPL version 3 or higher.
 -}

{-# LANGUAGE QuasiQuotes, TemplateHaskell, OverloadedStrings #-}

module Assistant.WebApp.Repair where

import Assistant.WebApp.Common
import Assistant.WebApp.Utility
import Assistant.WebApp.RepoList
import Remote (prettyUUID)
import Command.Repair (repairAnnexBranch)
import Git.Repair (runRepairOf)
import Logs.FsckResults
import Annex.UUID
import Utility.Batch
import Config.Files

import Control.Concurrent.Async

getRepairRepositoryR :: UUID -> Handler Html
getRepairRepositoryR = postRepairRepositoryR
postRepairRepositoryR :: UUID -> Handler Html
postRepairRepositoryR u = page "Repair repository" Nothing $ do
	repodesc <- liftAnnex $ prettyUUID u
	$(widgetFile "control/repairrepository")

getRepairRepositoryRunR :: UUID -> Handler Html
getRepairRepositoryRunR = postRepairRepositoryRunR
postRepairRepositoryRunR :: UUID -> Handler Html
postRepairRepositoryRunR u = do
	-- Stop the watcher from running while running repairs.
	changeSyncable Nothing False

	fsckthread <- liftAssistant $ runRepair u

	-- Start the watcher running again. This also triggers it to do a
	-- startup scan, which is especially important if the git repo
	-- repair removed files from the index file. Those files will be
	-- seen as new, and re-added to the repository.
	changeSyncable Nothing True

	liftAnnex $ writeFsckResults u Nothing

	page "Repair repository" Nothing $ do
		let repolist = repoListDisplay $
			mainRepoSelector { nudgeAddMore = True }
		$(widgetFile "control/repairrepository/done")

runRepair :: UUID -> Assistant ()
runRepair u = do
	fsckresults <- liftAnnex (readFsckResults u)
	myu <- liftAnnex getUUID
	if u == myu
		then localrepair fsckresults
		else remoterepair fsckresults
  where
  	localrepair fsckresults = do
		-- This intentionally runs the repair inside the Annex
		-- monad, which is not stricktly necessary, but keeps
		-- other threads that might be trying to use the Annex
		-- from running until it completes.
		needfsck <- liftAnnex $ do
			(ok, stillmissing, modifiedbranches) <- inRepo $
				runRepairOf fsckresults True
			repairAnnexBranch stillmissing modifiedbranches
			return (not ok)
		when needfsck $
			backgroundfsck [ Param "--fast" ]

	remoterepair fsckresults = do
		error "TODO: remote repair"
	
	backgroundfsck params = liftIO $ void $ async $ do
		program <- readProgramFile
		batchCommand program (Param "fsck" : params)