src/TSN/Picklers.hs

   1 -- | (Un)picklers for data types present in The Sports Network XML
   2 --   feed.
   3 --
   4 module TSN.Picklers (
   5   xp_date,
   6   xp_team_id )
   7 where
   8
   9 import Data.Time.Clock ( UTCTime )
  10 import Data.Time.Format ( formatTime, parseTime )
  11 import System.Locale ( defaultTimeLocale )
  12 import Text.Printf ( printf )
  13 import Text.Read ( readMaybe )
  14 import Text.XML.HXT.Arrow.Pickle (
  15   xpText,
  16   xpWrapMaybe )
  17 import Text.XML.HXT.Arrow.Pickle.Xml ( PU )
  18
  19
  20 -- | (Un)pickle a UTCTime without the time portion.
  21 --
  22 xp_date :: PU UTCTime
  23 xp_date =
  24   (to_date, from_date) `xpWrapMaybe` xpText
  25   where
  26     format = "%-m/%-d/%Y"
  27
  28     to_date :: String -> Maybe UTCTime
  29     to_date = parseTime defaultTimeLocale format
  30
  31     from_date :: UTCTime -> String
  32     from_date = formatTime defaultTimeLocale format
  33
  34
  35 -- | Parse a team_id. This *should* just be an 'Int', but TSN is doing
  36 --   something weird. First of all, player IDs do look like normal
  37 --   'Int's. But the team IDs are all stuck in the triple digits, and
  38 --   double-digit team IDs appear to be padded to three characters
  39 --   with a leading '0'. So maybe they're treating these as text?
  40 --
  41 --   In any case, we do the simplest thing that is correct for all the
  42 --   XML we've got: pad it to (only) three digits on pickling.
  43 --
  44 xp_team_id :: PU Int
  45 xp_team_id =
  46   (to_team_id, from_team_id) `xpWrapMaybe` xpText
  47   where
  48     to_team_id :: String -> Maybe Int
  49     to_team_id = readMaybe
  50
  51     from_team_id :: Int -> String
  52     from_team_id = printf "%03d"