import Control.Concurrent (forkIO, threadDelay)
import Control.Monad (forever, when)
+import Data.List ((\\))
import System.Exit (ExitCode(..), exitWith)
import System.IO (hPutStrLn, stderr)
import CommandLine
+import Configuration (Cfg(..))
import ExitCodes
import Mail
import Twitter.Http
import Twitter.User
--- The length of all calls to sleep, in seconds.
-heartbeat :: Int
-heartbeat = 600
-
+-- |A wrapper around threadDelay which takes seconds instead of
+-- microseconds as its argument.
thread_sleep :: Int -> IO ()
-thread_sleep microseconds = do
- let seconds = microseconds * (10 ^ (6 :: Int))
- threadDelay seconds
+thread_sleep seconds = do
+ let microseconds = seconds * (10 ^ (6 :: Int))
+ threadDelay microseconds
-message_from_status :: Message -> Status -> Message
-message_from_status message status =
- message { subject = "Twat: " ++ (screen_name (user status)),
- body = (pretty_print status) }
+-- |Given a 'Message', 'Status', and default date, update that
+-- message's body and subject with the information contained in the
+-- status. Adds a /Date: / header, and returns the updated message.
+message_from_status :: Message -> String -> Status -> Message
+message_from_status message default_date status =
+ message { subject = "Twat: " ++ (screen_name (user status)),
+ body = (pretty_print status),
+ headers = ((headers message) ++ ["Date: " ++ date])}
+ where
+ -- Use the Status' created_at date if it can be coerced into
+ -- RFC822 format.
+ date = case (created_at_to_rfc822 $ created_at status) of
+ Nothing -> default_date
+ Just c -> c
-recurse :: String -> Integer -> (Maybe Message) -> IO ()
-recurse username latest_status_id maybe_message = do
- thread_sleep heartbeat
- xmldata <- get_user_new_statuses username latest_status_id
+-- | If the given Message is not Nothing, send a copy of it for every
+-- Status in the list.
+send_messages :: Maybe Message -> [Status] -> IO ()
+send_messages maybe_message statuses =
+ case maybe_message of
+ Nothing -> return ()
+ Just message -> do
+ default_date <- rfc822_now
+ let mfs = message_from_status message (default_date)
+ let messages = map mfs statuses
+ sendmail_results <- mapM sendmail messages
+ _ <- mapM print_sendmail_result sendmail_results
+ return ()
- -- Parsing an empty result can blow up. Just pretend there are
- -- no new statuses in that case.
- let new_statuses = case xmldata of
- Just xml -> parse_statuses xml
- Nothing -> []
- case (length new_statuses) of
- 0 ->
- recurse username latest_status_id maybe_message
- _ -> do
- let new_latest_status_id = get_max_status_id new_statuses
- mapM (putStrLn . pretty_print) new_statuses
- case maybe_message of
- Nothing -> do
- recurse username new_latest_status_id maybe_message
- return ()
- Just message -> do
- let messages = map (message_from_status message) new_statuses
- sendmail_results <- mapM sendmail messages
- mapM print_sendmail_result sendmail_results
- recurse username new_latest_status_id maybe_message
- return ()
+-- | Display the number of skipped replies if ignore_replies is true
+-- and verbose is enabled.
+mention_replies :: Cfg -> [Status] -> IO ()
+mention_replies cfg ss = do
+ let replies = filter reply ss
+ when ((ignore_replies cfg) && (verbose cfg)) $ do
+ let countstr = show $ length replies
+ putStrLn $ "Ignoring " ++ countstr ++ " replies."
+
+
+-- | Display the number of skipped retweets if ignore_retweets is true
+-- and verbose is enabled.
+mention_retweets :: Cfg -> [Status] -> IO ()
+mention_retweets cfg ss = do
+ let retweets = filter retweet ss
+ when ((ignore_retweets cfg) && (verbose cfg)) $ do
+ let countstr = show $ length retweets
+ putStrLn $ "Ignoring " ++ countstr ++ " retweets."
+
+
+
+-- | Filter out replies/retweets based on the configuration.
+filter_statuses :: Cfg -> [Status] -> [Status]
+filter_statuses cfg ss =
+ good_statuses
+ where
+ replies = filter reply ss
+ retweets = filter retweet ss
+
+ good_statuses' = case (ignore_replies cfg) of
+ True -> ss \\ replies
+ False -> ss
+
+ good_statuses = case (ignore_retweets cfg) of
+ True -> good_statuses' \\ retweets
+ False -> good_statuses'
+
+
+
+-- | This is the main recursive loop. It takes a the configuration, a
+-- username, a latest_status_id, and optionally a 'Message' as
+-- arguments. The latest_status_id is the last status (that we know
+-- of) to be posted to username's Twitter account. If we find any
+-- newer statuses when we check, they are printed and optionally
+-- emailed (if a 'Message' was supplied). Then, the process repeats.
+recurse :: Cfg -> String -> Integer -> (Maybe Message) -> IO ()
+recurse cfg username latest_status_id maybe_message = do
+ thread_sleep (heartbeat cfg)
+ xmldata <- get_user_new_statuses username latest_status_id
+
+ -- Parsing an empty result can blow up. Just pretend there are
+ -- no new statuses in that case.
+ let new_statuses = case xmldata of
+ Just xml -> parse_statuses xml
+ Nothing -> []
+
+ case (length new_statuses) of
+ 0 ->
+ do_recurse latest_status_id
+ _ -> do
+
+ mention_replies cfg new_statuses
+ mention_retweets cfg new_statuses
+ let good_statuses = filter_statuses cfg new_statuses
-get_latest_status_id :: String -> IO Integer
-get_latest_status_id username = do
+ _ <- mapM (putStrLn . pretty_print) good_statuses
+
+ send_messages maybe_message good_statuses
+
+ let new_latest_status_id = get_max_status_id new_statuses
+ do_recurse new_latest_status_id
+
+ where
+ -- This lets us write all of these parameters once rather
+ -- than... more than once.
+ do_recurse :: Integer -> IO ()
+ do_recurse lsi = recurse cfg username lsi maybe_message
+
+
+-- | Try continually to download username's timeline, and determine the
+-- latest status id to be posted once we have done so.
+get_latest_status_id :: Int -> String -> IO Integer
+get_latest_status_id delay username = do
xmldata <- get_user_timeline username
let initial_statuses = case xmldata of
0 -> do
-- If the HTTP part barfs, try again after a while.
putStrLn ("Couldn't retrieve " ++ username ++ "'s timeline. Retrying...")
- thread_sleep heartbeat
- get_latest_status_id username
+ thread_sleep delay
+ get_latest_status_id delay username
_ -> return (get_max_status_id initial_statuses)
-run_twat :: Maybe Message -> String -> IO ()
-run_twat message username = do
- latest_status_id <- get_latest_status_id username
- recurse username latest_status_id message
+-- | This function wraps two steps. First, we need to find the latest
+-- status id posted by username. Once we have that, we can begin the
+-- recursive loop that checks for updates forever. The message
+-- argument is optional and is passed to recurse in case the updates
+-- should be emailed.
+run_twat :: Cfg -> Maybe Message -> String -> IO ()
+run_twat cfg msg username = do
+ latest_status_id <- get_latest_status_id (heartbeat cfg) username
+ recurse cfg username latest_status_id msg
return ()
+
+-- | Take advantage of the Maybe monad to only return a message when
+-- we have both a "to" and "from" address.
+construct_message :: Cfg -> Maybe Message
+construct_message cfg = do
+ to_addr <- to_address cfg
+ from_addr <- from_address cfg
+ return $ make_msg to_addr from_addr
+ where
+ make_msg t f = Message { headers = default_headers,
+ body = "",
+ subject = "",
+ to = t,
+ from = f }
+
+-- |The main function just parses the command-line arguments and then
+-- forks off calls to 'run_twat' for each supplied username. After
+-- forking, main loops forever.
main :: IO ()
main = do
errors <- parse_errors
-- Next, check to see if the 'help' option was passed to the
-- program. If it was, display the help, and exit successfully.
- help_opt_set <- help_set
- when help_opt_set $ do
- putStrLn help_text
- exitWith ExitSuccess
+ help <- help_set
+ when (help) $ do
+ putStrLn help_text
+ exitWith ExitSuccess
+ -- Get the list of usernames.
usernames <- parse_usernames
+ -- And a Cfg object.
+ cfg <- get_cfg
+
-- If we have both a "To" and "From" address, we'll create a
-- message object to be passed to all of our threads.
- to_address <- to_email_address
- from_address <- from_email_address
- let message = case to_address of
- Nothing -> Nothing
- Just toaddr ->
- case from_address of
- Nothing -> Nothing
- Just fromaddr ->
- Just (Message { headers = [],
- body = "",
- subject = "",
- to = toaddr,
- from = fromaddr })
+ let message = construct_message cfg
-- Execute run_twat on each username in a new thread.
- mapM (forkIO . (run_twat message)) usernames
+ let run_twat_curried = run_twat cfg message
+ _ <- mapM (forkIO . run_twat_curried) usernames
- forever $ do
+ _ <- forever $ do
-- This thread (the one executing main) doesn't do anything,
-- but when it terminates, so do all the threads we forked.
-- As a result, we need to keep this thread on life support.
- thread_sleep heartbeat
+ thread_sleep (heartbeat cfg)
return ()
+
+
+-- | A debugging tool that will parse, print, and email a single
+-- status (given by its id).
+twat_single_status :: Integer -> (Maybe Message) -> IO ()
+twat_single_status the_status_id maybe_message = do
+ xmldata <- get_status the_status_id
+
+ -- Parsing an empty result can blow up. Just pretend there are
+ -- no new statuses in that case.
+ let statuses = case xmldata of
+ Just xml -> parse_status xml
+ Nothing -> []
+
+ case (length statuses) of
+ 0 -> do
+ putStrLn "No statuses returned."
+ return ()
+ _ -> do
+ _ <- mapM (putStrLn . pretty_print) statuses
+
+ case maybe_message of
+ Nothing -> do
+ putStrLn "No message object given."
+ return ()
+ Just message -> do
+ default_date <- rfc822_now
+ let messages = map (message_from_status message (default_date)) statuses
+ sendmail_results <- mapM sendmail messages
+ _ <- mapM print_sendmail_result sendmail_results
+ return ()