module Twitter.Http
where

import Network.Curl
import System.IO (hPutStrLn, stderr)

-- |The API URL of username's timeline.
--
-- See,
--
--   <http://dev.twitter.com/doc/get/statuses/user_timeline>
--
user_timeline_url :: String -> String
user_timeline_url username =
    concat [ "http://api.twitter.com/1/statuses/user_timeline.xml",
             "?screen_name=" ++ username,
             "&include_rts=true",
             "&count=10" ]

-- |Given username's last status id, constructs the API URL for
-- username's new statuses. Essentially, 'user_timeline_url' with a
-- "since_id" parameter tacked on.
user_new_statuses_url :: String -> Integer -> String
user_new_statuses_url username last_status_id =
    concat [ user_timeline_url username,
             "&since_id=" ++ (show last_status_id) ]


-- |Return's username's timeline, or 'Nothing' if there was an error.
get_user_timeline :: String -> IO (Maybe String)
get_user_timeline username = do
  let uri = (user_timeline_url username)
  timeline <- (http_get uri)
  return timeline


-- Returns the XML representing all of username's statuses that are
-- newer than last_status_id.
get_user_new_statuses :: String -> Integer -> IO (Maybe String)
get_user_new_statuses username last_status_id = do
  let uri = (user_new_statuses_url username last_status_id)
  new_statuses <- (http_get uri)
  return new_statuses


-- |Uses the CURL API to retrieve uri. Returns 'Nothing' if there was
-- an error.
http_get :: String -> IO (Maybe String)
http_get uri = withCurlDo $ do
  resp <- curlGetString uri [CurlTimeout 45]

  case resp of
    (CurlOK, body) -> return (Just body)
    (code, _) -> do
        hPutStrLn stderr ("HTTP Error: " ++ (show code))
        return Nothing