2 files changed, 426 insertions, 0 deletions

diff --git a/bittorrent.cabal b/bittorrent.cabal
index 41782605..2f30d848 100644
--- a/bittorrent.cabal
+++ b/bittorrent.cabal
@@ -241,6 +241,42 @@ test-suite spec
 --                     , bittorrent
 --  ghc-options:         -O2 -Wall -fno-warn-orphans
 
+-- Utility to work with torrent files.
+executable mktorrent
+  if !flag(examples)
+    buildable:         False
+  default-language:    Haskell2010
+  hs-source-dirs:      examples
+  main-is:             MkTorrent.hs
+  other-modules:       Paths_bittorrent
+--                     , MkTorrent.Amend
+--                     , MkTorrent.Check
+--                     , MkTorrent.Create
+--                     , MkTorrent.Magnet
+--                     , MkTorrent.Show
+  build-depends:       base == 4.6.*
+                     , lens
+                     , time
+
+                     , bytestring
+
+                     , stm
+                     , async
+                     , parallel
+
+                     , text
+                     , pretty
+                     , pretty-class
+                     , network
+                     , bittorrent
+
+                     , optparse-applicative
+                     , directory
+                     , filepath
+                     , hslogger
+  ghc-options:         -Wall -threaded
+
+-- Utility to fetch
 executable gettorrent
   if !flag(examples)
     buildable:         False
@@ -256,6 +292,7 @@ executable gettorrent
                      , filepath
                      , bittorrent
 
+-- nonfunctioning example of very basic bittorrent client
 executable client
   if !flag(examples)
     buildable:         False
diff --git a/examples/MkTorrent.hs b/examples/MkTorrent.hs
new file mode 100644
index 00000000..ca7f5942
--- /dev/null
+++ b/examples/MkTorrent.hs
@@ -0,0 +1,389 @@
+{-# LANGUAGE OverloadedStrings  #-}
+{-# LANGUAGE RecordWildCards    #-}
+{-# LANGUAGE StandaloneDeriving #-}
+{-# OPTIONS -fno-warn-orphans   #-}
+module Main (main) where
+
+import Prelude as P
+import Control.Exception
+import Control.Lens hiding (argument)
+import Control.Monad
+import Data.List as L
+import Data.Monoid
+import Data.Text as T
+import qualified Data.Text.IO as T
+import Data.Text.Read as T
+import Data.Version
+import Network.URI
+import Options.Applicative
+import System.Log
+import System.Log.Logger
+import System.Exit
+import Text.Read
+import Text.PrettyPrint.Class
+
+import Paths_bittorrent (version)
+import Data.Torrent
+import Data.Torrent.Magnet hiding (Magnet (Magnet))
+import Data.Torrent.Magnet (Magnet)
+
+--import MkTorrent.Check
+--import MkTorrent.Create
+
+{-----------------------------------------------------------------------
+--  Dialogs
+-----------------------------------------------------------------------}
+
+instance Read URI where
+  readsPrec _ = f . parseURI
+    where
+      f Nothing  = []
+      f (Just u) = [(u, "")]
+
+question :: Show a => Text -> Maybe a -> IO ()
+question q def = do
+  T.putStrLn q
+  case def of
+    Nothing -> return ()
+    Just v  -> T.putStrLn $ "[default: " <> T.pack (show v) <> "]"
+
+ask :: Read a => Text -> IO a
+ask q = question q (Just True) >> getReply
+  where
+    getReply = do
+      resp <- P.getLine
+      maybe getReply return $ readMaybe resp
+
+askMaybe :: Read a => Text -> IO (Maybe a)
+askMaybe q = question q (Just False) >> getReply
+  where
+    getReply = do
+      resp <- P.getLine
+      if resp == []
+        then return Nothing
+        else maybe getReply return $ readMaybe resp
+
+askURI :: IO URI
+askURI = do
+  str <- P.getLine
+  case parseURI str of
+    Nothing -> T.putStrLn "incorrect URI" >> askURI
+    Just u  -> return u
+
+askFreeform :: IO Text
+askFreeform = do
+  str <- T.getLine
+  if T.null str
+    then askFreeform
+    else return str
+
+askInRange :: Int -> Int -> IO Int
+askInRange a b = do
+  str <- T.getLine
+  case T.decimal str of
+    Left msg -> do
+      P.putStrLn msg
+      askInRange a b
+    Right (i, _)
+      | a <= i && i < b -> return i
+      |     otherwise   -> do
+        T.putStrLn "not in range "
+        askInRange a b
+
+askChoice :: [(Text, a)] -> IO a
+askChoice kvs = do
+  forM_ (L.zip [1 :: Int ..] $ L.map fst kvs) $ \(i, lbl) -> do
+    T.putStrLn $ "  " <> T.pack (show i) <> ") " <> lbl
+  T.putStrLn "Your choice?"
+  ix <- askInRange 1 (succ (L.length kvs))
+  return $ snd (kvs !! pred ix)
+
+{-----------------------------------------------------------------------
+--  Helpers
+-----------------------------------------------------------------------}
+
+torrentFile :: Parser FilePath
+torrentFile = argument Just
+    ( metavar "FILE"
+   <> help    "A .torrent file"
+    )
+
+{-----------------------------------------------------------------------
+--  Amend command
+-----------------------------------------------------------------------}
+
+data AmendOpts = AmendOpts FilePath
+  deriving Show
+
+amendOpts :: Parser AmendOpts
+amendOpts = AmendOpts <$> torrentFile
+
+amendInfo :: ParserInfo AmendOpts
+amendInfo = info (helper <*> amendOpts) modifier
+  where
+    modifier = progDesc "Edit info fields of existing torrent"
+
+type Amend = Torrent -> Torrent
+
+fields :: [(Text, IO Amend)]
+fields = [ ("announce",      set announce            <$> askURI)
+         , ("comment",       set comment      . Just <$> askFreeform)
+         , ("created by",    set createdBy    . Just <$> askFreeform)
+         , ("publisher url", set publisherURL . Just <$> askURI)
+         ]
+
+askAmend :: IO Amend
+askAmend = join $ T.putStrLn "Choose a field:" >> askChoice fields
+
+amend :: AmendOpts -> IO Bool
+amend (AmendOpts tpath) = do
+  t <- fromFile tpath
+  a <- askAmend
+  toFile tpath $ a t
+  return True
+
+{-----------------------------------------------------------------------
+--  Check command
+-----------------------------------------------------------------------}
+
+{-
+checkOpts :: Parser CheckOpts
+checkOpts = CheckOpts
+    <$> torrentFile
+    <*> argument Just
+        ( metavar "PATH"
+       <> value   "."
+       <> help    "Content directory or a single file" )
+
+checkInfo :: ParserInfo CheckOpts
+checkInfo = info (helper <*> checkOpts) modifier
+  where
+    modifier = progDesc "Validate integrity of torrent data"
+
+{-----------------------------------------------------------------------
+--  Create command
+-----------------------------------------------------------------------}
+
+createFlags :: Parser CreateFlags
+createFlags = CreateFlags
+    <$> optional (option
+      ( long    "piece-size"
+     <> short   's'
+     <> metavar "SIZE"
+     <> help    "Set size of torrent pieces"
+      ))
+    <*> switch
+      ( long    "md5"
+     <> short   '5'
+     <> help    "Include md5 hash of each file"
+      )
+    <*> switch
+      ( long    "ignore-dot-files"
+     <> short   'd'
+     <> help    "Do not include .* files"
+      )
+
+
+createOpts :: Parser CreateOpts
+createOpts = CreateOpts
+    <$> argument Just
+        ( metavar "PATH"
+       <> help    "Content directory or a single file"
+        )
+    <*> optional (argument Just
+        ( metavar "FILE"
+       <> help    "Place for the output .torrent file"
+        ))
+    <*> createFlags
+
+createInfo :: ParserInfo CreateOpts
+createInfo = info (helper <*> createOpts) modifier
+  where
+    modifier = progDesc "Make a new .torrent file"
+-}
+
+{-----------------------------------------------------------------------
+--  Magnet command
+-----------------------------------------------------------------------}
+
+data MagnetFlags = MagnetFlags
+  { detailed :: Bool
+  } deriving Show
+
+data MagnetOpts = MagnetOpts FilePath MagnetFlags
+  deriving Show
+
+magnetFlags :: Parser MagnetFlags
+magnetFlags = MagnetFlags
+    <$> switch
+       ( long "detailed"
+       )
+
+magnetOpts :: Parser MagnetOpts
+magnetOpts = MagnetOpts <$> torrentFile <*> magnetFlags
+
+magnetInfo :: ParserInfo MagnetOpts
+magnetInfo = info (helper <*> magnetOpts) modifier
+  where
+    modifier = progDesc "Print magnet link"
+
+mkMagnet :: MagnetFlags -> Torrent -> Magnet
+mkMagnet MagnetFlags {..} = if detailed then detailedMagnet else simpleMagnet
+
+magnet :: MagnetOpts -> IO Bool
+magnet (MagnetOpts tpath flags) = do
+  print . mkMagnet flags =<< fromFile tpath
+  return True
+
+{-----------------------------------------------------------------------
+--  Show command
+-----------------------------------------------------------------------}
+
+data ShowFlags = ShowFlags
+  { infoHashOnly :: Bool
+  } deriving Show
+
+data ShowOpts = ShowOpts FilePath ShowFlags
+  deriving Show
+
+showFlags :: Parser ShowFlags
+showFlags = ShowFlags
+  <$> switch
+      ( long "infohash"
+     <> help "Show only hash of the torrent info part"
+      )
+
+showOpts :: Parser ShowOpts
+showOpts = ShowOpts <$> torrentFile <*> showFlags
+
+showInfo :: ParserInfo ShowOpts
+showInfo = info (helper <*> showOpts) modifier
+  where
+    modifier = progDesc "Print .torrent file metadata"
+
+showTorrent :: ShowFlags -> Torrent -> ShowS
+showTorrent ShowFlags {..} torrent
+  | infoHashOnly = shows $ idInfoHash (tInfoDict torrent)
+  |   otherwise  = shows $ pretty torrent
+
+putTorrent :: ShowOpts -> IO Bool
+putTorrent (ShowOpts torrentPath flags) = do
+    torrent <- fromFile torrentPath `onException` putStrLn help
+    putStrLn $ showTorrent flags torrent []
+    return True
+  where
+    help = "Most likely this is not a valid .torrent file"
+
+{-----------------------------------------------------------------------
+--  Command
+-----------------------------------------------------------------------}
+
+data Command
+  = Amend  AmendOpts
+--  | Check  CheckOpts
+--  | Create CreateOpts
+  | Magnet MagnetOpts
+  | Show   ShowOpts
+    deriving Show
+
+commandOpts :: Parser Command
+commandOpts = subparser $ mconcat
+    [ command "amend"  (Amend  <$> amendInfo)
+--    , command "check"  (Check  <$> checkInfo)
+--    , command "create" (Create <$> createInfo)
+    , command "magnet" (Magnet <$> magnetInfo)
+    , command "show"   (Show   <$> showInfo)
+    ]
+
+{-----------------------------------------------------------------------
+--  Global Options
+-----------------------------------------------------------------------}
+
+data GlobalOpts = GlobalOpts
+  { verbosity   :: Priority
+  } deriving Show
+
+deriving instance Enum    Priority
+deriving instance Bounded Priority
+
+priorities :: [Priority]
+priorities = [minBound..maxBound]
+
+defaultPriority :: Priority
+defaultPriority = WARNING
+
+verbosityOpts :: Parser Priority
+verbosityOpts = verbosityP <|> verboseP <|> quietP
+  where
+    verbosityP = option
+      ( long    "verbosity"
+     <> metavar "LEVEL"
+     <> help   ("Set verbosity level\n"
+             ++ "Possible values are " ++ show priorities)
+      )
+
+    verboseP = flag defaultPriority INFO
+      ( long    "verbose"
+     <> short   'v'
+     <> help    "Verbose mode"
+      )
+
+    quietP = flag defaultPriority CRITICAL
+      ( long    "quiet"
+     <> short   'q'
+     <> help    "Silent mode"
+      )
+
+
+globalOpts :: Parser GlobalOpts
+globalOpts = GlobalOpts <$> verbosityOpts
+
+data Options = Options
+  { cmdOpts  :: Command
+  , globOpts :: GlobalOpts
+  } deriving Show
+
+options :: Parser Options
+options = Options <$> commandOpts <*> globalOpts
+
+versioner :: String -> Version -> Parser (a -> a)
+versioner prog ver = nullOption $ mconcat
+    [ long  "version"
+    , help  "Show program version and exit"
+    , value id
+    , metavar ""
+    , hidden
+    , reader $ const $ undefined -- Left $ ErrorMsg versionStr
+    ]
+  where
+    versionStr = prog ++ " version " ++ showVersion ver
+
+parserInfo :: ParserInfo Options
+parserInfo = info parser modifier
+  where
+    parser   = helper <*> versioner "mktorrent" version <*> options
+    modifier = header synopsis <> progDesc description <> fullDesc
+    synopsis    = "Torrent management utility"
+    description = "" -- TODO
+
+{-----------------------------------------------------------------------
+--  Dispatch
+-----------------------------------------------------------------------}
+
+run :: Command -> IO Bool
+run (Amend  opts) = amend opts
+--run (Check  opts) = checkTorrent opts
+--run (Create opts) = createTorrent opts
+run (Magnet opts) = magnet opts
+run (Show   opts) = putTorrent opts
+
+prepare :: GlobalOpts -> IO ()
+prepare GlobalOpts {..} = do
+  updateGlobalLogger rootLoggerName (setLevel verbosity)
+
+main :: IO ()
+main = do
+  Options {..} <- execParser parserInfo
+  prepare globOpts
+  success <- run cmdOpts
+  if success then exitSuccess else exitFailure
\ No newline at end of file