From 30a3dc92168c3c82d4cfd7a773cd3b63f34a6b03 Mon Sep 17 00:00:00 2001
From: Sam Truzjan <pxqr.sta@gmail.com>
Date: Fri, 3 Jan 2014 22:51:16 +0400
Subject: Add basic gettorrent implementation

---
 bittorrent.cabal       |  4 ++++
 examples/GetTorrent.hs | 53 +++++++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 52 insertions(+), 5 deletions(-)

diff --git a/bittorrent.cabal b/bittorrent.cabal
index 347cc38d..f1b2823f 100644
--- a/bittorrent.cabal
+++ b/bittorrent.cabal
@@ -244,6 +244,10 @@ executable gettorrent
   build-depends:       base        == 4.*
                      , optparse-applicative
                      , data-default
+                     , conduit
+                     , mtl
+                     , network
+                     , filepath
                      , bittorrent
 
 executable client-example
diff --git a/examples/GetTorrent.hs b/examples/GetTorrent.hs
index a9d2a44f..5e624fa1 100644
--- a/examples/GetTorrent.hs
+++ b/examples/GetTorrent.hs
@@ -1,27 +1,49 @@
+{-# LANGUAGE RecordWildCards #-}
 module Main (main) where
+import Control.Applicative
+import Control.Concurrent
+import Control.Monad
+import Control.Monad.Trans
+import Data.Conduit as C
+import Data.Conduit.List as C
 import Data.Default
-
+import Data.Maybe
+import Network.URI
 import Options.Applicative
+import System.Exit
+import System.FilePath
+
+import Data.Torrent
 import Data.Torrent.InfoHash
 import Network.BitTorrent.Core
+import Network.BitTorrent.DHT.Session
+import Network.BitTorrent.DHT as DHT
+import Network.BitTorrent.Exchange.Message
+import Network.BitTorrent.Exchange.Wire
 
 
 data Params = Params
-  { infohash :: InfoHash
+  { topic    :: InfoHash
   , thisNode :: NodeAddr IPv4
   , bootNode :: NodeAddr IPv4
+  , buckets  :: Int
   } deriving Show
 
 paramsParser :: Parser Params
 paramsParser = Params
   <$> option (long    "infohash" <> short 'i'
            <> metavar "SHA1"     <> help "infohash of torrent file")
-  <*> option (long    "node"     <> short 'n' <> value def
-           <> metavar "NODE"     <> help "this node address"
+  <*> option (long    "port"     <> short 'p'
+           <> value def          <> showDefault
+           <> metavar "NUM"      <> help "port number to bind"
              )
   <*> option (long    "boot"     <> short 'b'
            <> metavar "NODE"     <> help "bootstrap node address"
              )
+  <*> option (long    "bucket"   <> short 'n'
+           <> value 2            <> showDefault
+           <> metavar "NUM"      <> help "number of buckets to maintain"
+             )
 
 programInfo :: ParserInfo Params
 programInfo = info (helper <*> paramsParser)
@@ -30,8 +52,29 @@ programInfo = info (helper <*> paramsParser)
   <> header   "gettorrent - get torrent file by infohash"
    )
 
+fakeTracker :: URI
+fakeTracker = fromJust $ parseURI "http://foo.org"
+
+exchangeTorrent :: PeerAddr IP -> InfoHash -> IO InfoDict
+exchangeTorrent addr ih = do
+  pid <- genPeerId
+  var <- newEmptyMVar
+  let hs = Handshake def (toCaps [ExtExtended]) ih pid
+  connectWire hs addr (toCaps [ExtMetadata]) $ do
+    infodict <- getMetadata
+    liftIO $ putMVar var infodict
+  takeMVar var
+
 getTorrent :: Params -> IO ()
-getTorrent = print
+getTorrent Params {..} = do
+  dht (def { optBucketCount = buckets }) thisNode $ do
+    bootstrap [bootNode]
+    DHT.lookup topic $$ C.mapM_ $ \ peers -> do
+      liftIO $ forM_ peers $ \ peer -> do
+        infodict <- exchangeTorrent (IPv4 <$> peer) topic
+        let torrent = nullTorrent fakeTracker infodict
+        toFile (show topic <.> torrentExt) torrent
+        exitSuccess
 
 main :: IO ()
 main = execParser programInfo >>= getTorrent
-- 
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