module Homework.Ch02.Log where

data MessageType
  = Info
  | Warning
  | Error Int
  deriving (Show, Eq)

type TimeStamp = Int

data LogMessage
  = LogMessage MessageType TimeStamp String
  | Unknown String
  deriving (Show, Eq)

data MessageTree
  = Leaf
  | Node MessageTree LogMessage MessageTree
  deriving (Show, Eq)

-- | @testParse p n f@ tests the log file parser @p@ by running it
--   on the first @n@ lines of file @f@.
testParse ::
  (String -> [LogMessage]) ->
  Int ->
  FilePath ->
  IO [LogMessage]
testParse parse n file = take n . parse <$> readFile file

-- | @testWhatWentWrong p w f@ tests the log file parser @p@ and
--   warning message extractor @w@ by running them on the log file
--   @f@.
testWhatWentWrong ::
  (String -> [LogMessage]) ->
  ([LogMessage] -> [String]) ->
  FilePath ->
  IO [String]
testWhatWentWrong parse whatWentWrong file =
  whatWentWrong . parse <$> readFile file