import System.Locale ( defaultTimeLocale, rfc822DateFormat )
import Test.Tasty ( TestTree, testGroup )
import Test.Tasty.HUnit ( (@?=), testCase )
-import Text.Regex ( matchRegex, mkRegex )
import Html ( replace_entities )
import StringUtils ( listify )
import Twitter.User ( User(..), screen_name_to_timeline_url )
+
+-- | Representation of a Twitter user status. We only care about a few
+-- of the fields, and those are all that we bother to include in the
+-- representation.
+--
data Status = Status {
created_at :: Maybe UTCTime,
status_id :: Integer,
type Timeline = [Status]
+
instance FromJSON Status where
+ -- | Use a bunch of applicative magic to parse a 'Status' out of the
+ -- JSON that we get from the Twitter API.
+ --
parseJSON (Object t) =
Status <$>
liftM parse_status_time (t .: created_at_field) <*>
liftM replace_entities (t .: text_field) <*>
(t .: user_field)
where
- -- The typechecker flips out without this.
+ -- | The typechecker flips out without this; it's just a copy if
+ -- 'isJust' specialized to the 'Int' type.
+ --
isJustInt :: Maybe Int -> Bool
isJustInt = isJust
-- Do whatever.
parseJSON _ = mempty
+
-- | Parse a timestamp from a status into a UTCTime (or Nothing).
--
+-- Examples:
+--
+-- >>> let s = "Sun Oct 24 18:21:41 +0000 2010"
+-- >>> parse_status_time s
+-- Just 2010-10-24 18:21:41 UTC
+--
+-- >>> parse_status_time "what's up dawg"
+-- Nothing
+--
parse_status_time :: String -> Maybe UTCTime
parse_status_time =
parseTime defaultTimeLocale status_format
where
- -- | Should match e.g. "Sun Oct 24 18:21:41 +0000 2010"
status_format :: String
status_format = "%a %b %d %H:%M:%S %z %Y"
-- | Given a 'TimeZone', convert a 'UTCTime' into an RFC822-format
-- time string. If no 'TimeZone' is given, assume UTC.
--
+-- Examples:
+--
+-- >>> let s = "Sun Oct 24 18:21:41 +0000 2010"
+-- >>> let Just t = parse_status_time s
+-- >>> utc_time_to_rfc822 Nothing t
+-- "Sun, 24 Oct 2010 18:21:41 UTC"
+--
utc_time_to_rfc822 :: Maybe TimeZone -> UTCTime -> String
utc_time_to_rfc822 mtz utc =
case mtz of
-- RFC822-format time string. If there's no created-at time in the
-- status, you'll get an empty string instead.
--
+-- >>> let u = User "washington_irving"
+-- >>> let created = parse_status_time "Sun Oct 24 18:21:41 +0000 2010"
+-- >>> let s = Status created 8675309 False False "IM TWITTERING" u
+-- >>> show_created_at Nothing s
+-- "Sun, 24 Oct 2010 18:21:41 UTC"
+-- >>> show_created_at Nothing s{ created_at = Nothing }
+-- ""
+--
show_created_at :: Maybe TimeZone -> Status -> String
show_created_at mtz =
(maybe "" (utc_time_to_rfc822 mtz)) . created_at
-- | Returns a nicely-formatted String representing the given 'Status'
-- object.
--
+-- Examples:
+--
+-- >>> let u = User "washington_irving"
+-- >>> let created = parse_status_time "Sun Oct 24 18:21:41 +0000 2010"
+-- >>> let s = Status created 8675309 False False "IM TWITTERING" u
+-- >>> putStr $ pretty_print Nothing s
+-- washington_irving - Sun, 24 Oct 2010 18:21:41 UTC
+-- -------------------------------------------------
+-- IM TWITTERING
+-- <BLANKLINE>
+-- <BLANKLINE>
+--
pretty_print :: Maybe TimeZone -> Status -> String
pretty_print mtz status =
concat [ name,
-- | Given a list of statuses, returns the greatest status_id
-- belonging to one of the statuses in the list.
--
+-- Examples:
+--
+-- >>> let u = User "washington_irving"
+-- >>> let created = parse_status_time "Sun Oct 24 18:21:41 +0000 2010"
+-- >>> let s = Status created 8675309 False False "IM TWITTERING" u
+-- >>> let timeline = [s,s,s,s,s]
+-- >>> get_max_status_id timeline
+-- 8675309
+--
get_max_status_id :: Timeline -> Integer
get_max_status_id statuses =
maximum status_ids
status_ids = map status_id statuses
--- | Parse one username from a word.
+-- | Parse one username from a 'String'.
+--
+-- Examples:
+--
+-- >>> parse_username "@washington_irving"
+-- Just "washington_irving"
+-- >>> parse_username "washington_irving"
+-- Nothing
+-- >>> parse_username "Everbody loves @washington_irving, even Raymond"
+-- Just "washington_irving"
+--
+-- >>> parse_username "herp @@@ derp @washington_irving foo@@BAR"
+-- Just "washington_irving"
+--
+-- >>> parse_username "tailing at sign y'all @"
+-- Nothing
--
parse_username :: String -> Maybe String
-parse_username word =
- case matches of
- Nothing -> Nothing
- Just [] -> Nothing
- Just (first_match:_) -> Just first_match
+parse_username s
+ | null parse_result = Nothing
+ | otherwise = Just parse_result
where
- username_regex = mkRegex "@([a-zA-Z0-9_]+)"
- matches = matchRegex username_regex word
+ -- | A list of characters valid in a Twitter username.
+ --
+ username_chars :: String
+ username_chars = ['a'..'z'] ++ ['A'..'Z'] ++ ['0'..'9'] ++ "_"
+
+ -- | Take a string and drop everything (including the \'@\') up to
+ -- the first character of the first username (if one exists).
+ --
+ start_name :: String -> String
+ start_name w =
+ case dropWhile (/= '@') w of
+ [] -> []
+ (_:xs) -> xs
+
+ parse_userchars :: String -> String
+ parse_userchars = takeWhile (`elem` username_chars)
+
+ -- | Parse a username from the given String by dropping all
+ -- characters that don't belong to it. This function calls
+ -- itself recursively until it gets a username or runs out of
+ -- string.
+ --
+ parse_name :: String -> String
+ parse_name [] = []
+ parse_name rest@(_:xs) =
+ let ucs = (parse_userchars . start_name) rest in
+ case ucs of
+ [] -> parse_name xs
+ _ -> ucs
+
+ parse_result :: String
+ parse_result = parse_name s
-- | Parse all usernames of the form \@username from a status.
--
+-- Examples:
+--
+-- >>> let u = User "washington_irving"
+-- >>> let b = "YO WHERE'S @BONUS500 and @@@ I LOVE @AT SIGNS@"
+-- >>> let s = Status Nothing 8675309 False False b u
+-- >>> parse_usernames_from_status s
+-- ["BONUS500","AT"]
+--
parse_usernames_from_status :: Status -> [String]
parse_usernames_from_status status =
mapMaybe parse_username status_words
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