module Darcs.Commands.Check ( check ) where
import Control.Monad ( when )
import Control.Applicative( (<$>) )
import System.Exit ( ExitCode(..), exitWith )



import Darcs.Commands ( DarcsCommand(..), nodefaults, putInfo )
import Darcs.Arguments ( DarcsFlag(Quiet),
                        partialCheck, notest, testByDefault,
                        leaveTestDir, workingRepoDir, ignoretimes
                      )
import Darcs.Flags(willIgnoreTimes)
import Darcs.Repository.Repair( replayRepository, checkIndex
                              , RepositoryConsistency(..) )
import Darcs.Repository ( Repository, amInRepository, withRepository,
                          testRecorded, readRecorded )
import Darcs.Patch ( RepoPatch, showPatch )
import Darcs.Witnesses.Ordered ( FL(..) )
import Darcs.Repository.Prefs ( filetypeFunction )
import Darcs.Diff( treeDiff )
import Printer ( text, ($$), (<+>) )


checkDescription :: String
checkDescription = "Check the repository for consistency."

checkHelp :: String
checkHelp =
 "This command verifies that the patches in the repository, when applied\n" ++
 "successively to an empty tree, result in the pristine tree.  If not,\n" ++
 "the differences are printed and Darcs exits unsucessfully (with a\n" ++
 "non-zero exit status).\n" ++
 "\n" ++
 "If the repository is in darcs-1 format and has a checkpoint, you can\n" ++
 "use the --partial option to start checking from the latest checkpoint.\n" ++
 "This is the default for partial darcs-1 repositories; the --complete\n" ++
 "option to forces a full check.\n" ++
 "\n" ++
 "If a regression test is defined (see `darcs setpref') it will be run\n" ++
 "by `darcs check'.  Use the --no-test option to disable this.\n"

check :: DarcsCommand
check = DarcsCommand {commandName = "check",
                      commandHelp = checkHelp,
                      commandDescription = checkDescription,
                      commandExtraArgs = 0,
                      commandExtraArgHelp = [],
                      commandCommand = checkCmd,
                      commandPrereq = amInRepository,
                      commandGetArgPossibilities = return [],
                      commandArgdefaults = nodefaults,
                      commandAdvancedOptions = [],
                      commandBasicOptions = [partialCheck,
                                              notest,
                                              leaveTestDir,
                                              workingRepoDir,
                                               ignoretimes
                                             ]}

checkCmd :: [DarcsFlag] -> [String] -> IO ()
checkCmd opts _ = withRepository opts (check' opts)

check' :: (RepoPatch p) => [DarcsFlag] -> Repository p -> IO ()
check' opts repository = do
    failed <- replayRepository repository (testByDefault opts) $ \ state -> do
      case state of
        RepositoryConsistent -> do
          putInfo opts $ text "The repository is consistent!"
          testRecorded repository
          return False
        BrokenPristine newpris -> do
          brokenPristine newpris
          return True
        BrokenPatches newpris _ -> do
          brokenPristine newpris
          putInfo opts $ text "Found broken patches."
          return True
    bad_index <- case willIgnoreTimes opts of
                   False -> not <$> checkIndex repository (Quiet `elem` opts)
                   True -> return False
    when bad_index $ putInfo opts $ text "Bad index."
    exitWith $ if failed || bad_index then ExitFailure 1 else ExitSuccess
   where
     brokenPristine newpris = do
         putInfo opts $ text "Looks like we have a difference..."
         mc <- readRecorded repository
         ftf <- filetypeFunction
         diff <- treeDiff ftf newpris mc
         putInfo opts $ case diff of
                        NilFL -> text "Nothing"
                        patch -> text "Difference: " <+> showPatch patch
         putInfo opts $ text ""
                     $$ text "Inconsistent repository!"