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