Resume download from where it was left off last time

[functorrent.git] / src / main / Main.hs

diff --git a/src/main/Main.hs b/src/main/Main.hs
index b86f2e4284b1990fb2fdb4532b288c08006fda21..ae3c0354e76a7b714db629388211551bd091600f 100644 (file)
--- a/src/main/Main.hs
+++ b/src/main/Main.hs
@@ -2,22 +2,24 @@
 module Main where
 
 import Prelude hiding (log, length, readFile, getContents)
+
+import Control.Concurrent (forkIO)
 import Data.ByteString.Char8 (ByteString, getContents, readFile, unpack)
+import Network (PortID (PortNumber))
 import System.Environment (getArgs)
 import System.Exit (exitSuccess)
 import System.Directory (doesFileExist)
+import System.Random (getStdGen, randomRs)
 
 import FuncTorrent.Logger (initLogger, logMessage, logStop)
 import FuncTorrent.Metainfo (Info(..), Metainfo(..), torrentToMetainfo)
 import FuncTorrent.Peer (handlePeerMsgs)
+import qualified FuncTorrent.Server as Server
 import FuncTorrent.Tracker (peers, getTrackerResponse)
 
 logError :: String -> (String -> IO ()) -> IO ()
 logError e logMsg = logMsg $ "parse error: \n" ++ e
 
-peerId :: String
-peerId = "-HS0001-*-*-20150215"
-
 exit :: IO ByteString
 exit = exitSuccess
 
@@ -33,10 +35,21 @@ parse [a] = do
     else error "file does not exist"
 parse _ = exit
 
+-- peer id is exactly 20 bytes long.
+-- peer id starts with '-', followed by 2 char client id'
+-- followed by 4 ascii digits for version number, followed by
+-- a '-'. Rest are random digits to fill the 20 bytes.
+mkPeerID :: IO String
+mkPeerID = do
+  stdgen <- getStdGen
+  let digits = randomRs (0, 9) stdgen :: [Integer]
+  return $ "-HS9001-" ++ (concatMap show $ take (20 - 8) digits)
+
 main :: IO ()
 main = do
     args <- getArgs
     logR <- initLogger
+    peerId <- mkPeerID    
     let log = logMessage logR
     log "Starting up functorrent"
     log $ "Parsing arguments " ++ concat args
@@ -44,12 +57,20 @@ main = do
     case torrentToMetainfo torrentStr of
      Left e -> logError e log
      Right m -> do
-       log "Input File OK"
-       log $ "Downloading file : " ++ name (info m)
+       let p = name (info m)
+       log $ "Downloading file : " ++ p
+       -- if we had downloaded the file before (partly or completely)
+       -- then we should check the current directory for the existence
+       -- of the file and then update the map of each piece' availability.
+       -- This can be donw by reading each piece and verifying the checksum.
+       -- If the checksum does not match, we don't have that piece.
+       log $ "starting server"
+       (serverSock, (PortNumber portnum)) <- Server.start
+       log $ "server started on " ++ show portnum
        log "Trying to fetch peers"
-
+       forkIO $ Server.run serverSock peerId m
        log $ "Trackers: " ++ head (announceList m)
-       trackerResp <- getTrackerResponse peerId m
+       trackerResp <- getTrackerResponse portnum peerId m
        case  trackerResp of
         Left e -> log $ "Error" ++ unpack e
         Right peerList -> do