Yorgey class - week 2 exercise

week2-ex01.hs

{-# OPTIONS_GHC -Wall #-}
module LogAnalysis where

import Log
import qualified Data.Text as T
import Control.Monad
import Data.Char

parseMessage :: String -> LogMessage
parseMessage = parseMessage' . T.split (==' ') . T.pack

parseMessage' :: [T.Text] -> LogMessage
parseMessage' pieces
  | (=='I') label = LogMessage Info timestamp (T.unpack $ rejoin rest)
  | (=='W') label = LogMessage Warning timestamp (T.unpack $ rejoin rest)
  | (=='E') label = LogMessage (Error my_error) maybe_timestamp (T.unpack $ rejoin maybe_rest)
  | otherwise = Unknown (T.unpack $ rejoin pieces)
  where
    label = head . T.unpack . head $ pieces
    timestamp = parseInt (head . tail $ pieces) :: Int
    my_error = timestamp
    rest = tail . tail $ pieces
    maybe_timestamp = parseInt (head rest) :: Int
    maybe_rest = tail rest

parseInt :: T.Text -> Int
parseInt = read . T.unpack

rejoin :: [T.Text] -> T.Text
rejoin = T.intercalate (T.pack " ")