%  Copyright (C) 2008 David Roundy
%
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%  it under the terms of the GNU General Public License as published by
%  the Free Software Foundation; either version 2, or (at your option)
%  any later version.
%
%  This program is distributed in the hope that it will be useful,
%  but WITHOUT ANY WARRANTY; without even the implied warranty of
%  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
%  GNU General Public License for more details.
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%  along with this program; see the file COPYING.  If not, write to
%  the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
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\subsection{darcs changes}
\begin{code}
{-# OPTIONS_GHC -cpp -fglasgow-exts #-}
{-# LANGUAGE CPP, PatternGuards #-}

-- The pragma above is only for pattern guards.
module Darcs.Commands.TransferMode ( transfer_mode ) where

import Prelude hiding ( catch )
import Control.Exception ( catch )
import System.IO ( stdout, hFlush )

import Darcs.Utils ( withCurrentDirectory, prettyException )
import Darcs.Commands ( DarcsCommand(..), nodefaults )
import Darcs.Arguments ( DarcsFlag, working_repo_dir )
import Darcs.Repository ( amInRepository )
import Progress ( setProgressMode )
import Darcs.Global ( darcsdir )

import qualified Data.ByteString as B (hPut, readFile, length, ByteString)
\end{code}

\options{transfer_mode}
\begin{code}
transfer_mode_description :: String
transfer_mode_description = "Internal command for efficient ssh transfers."
\end{code}
\haskell{transfer_mode_help}
\begin{code}
transfer_mode_help :: String
transfer_mode_help =
 "When pulling from or pushing to a remote repository over ssh, if both\n" ++
 "the local and remote ends have Darcs 2, the `transfer-mode' command\n" ++
 "will be invoked on the remote end.  This allows Darcs to intelligently\n" ++
 "transfer information over a single ssh connection.\n" ++
 "\n" ++
 "If either end runs Darcs 1, a separate ssh connection will be created\n" ++
 "for each transfer.  As well as being less efficient, this means users\n" ++
 "who do not run ssh-agent will be prompted for the ssh password tens or\n" ++
 "hundreds of times!\n"

transfer_mode :: DarcsCommand
transfer_mode = DarcsCommand {command_name = "transfer-mode",
                              command_help = transfer_mode_help,
                              command_description = transfer_mode_description,
                              command_extra_args = 0,
                              command_extra_arg_help = [],
                              command_get_arg_possibilities = return [],
                              command_command = transfer_mode_cmd,
                              command_prereq = amInRepository,
                              command_argdefaults = nodefaults,
                              command_advanced_options = [],
                              command_basic_options = [working_repo_dir]}

transfer_mode_cmd :: [DarcsFlag] -> [String] -> IO ()
transfer_mode_cmd _ _ = do setProgressMode False
                           putStrLn "Hello user, I am darcs transfer mode"
                           hFlush stdout
                           withCurrentDirectory darcsdir $ transfer

transfer :: IO ()
transfer = do 'g':'e':'t':' ':fn <- getLine
              x <- readfile fn
              case x of
                Right c -> do putStrLn $ "got " ++ fn
                              putStrLn $ show $ B.length c
                              B.hPut stdout c
                              hFlush stdout
                Left e -> do putStrLn $ "error " ++ fn
                             putStrLn $ show e
                             hFlush stdout
              transfer

readfile :: String -> IO (Either String B.ByteString)
readfile fn = (Right `fmap` B.readFile fn) `catch` (\e -> return $ Left (prettyException e))
\end{code}