weechat log get sent msg count for each nick

nickMsgCnt.hs

{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE OverlappingInstances #-}

module Main where

import Data.Map (fromListWith, toList)

main :: IO ()
main = do
    let log = "date time Zerock henlo\n\
               \date time uptime i'm up\n\
               \date time cppxor2arr mwaaa\n\
               \date time -- nick change\n\
               \date time --> join info\n\
               \date time <-- quit info\n\
               \date time letty mwaa everyone\n\
               \date time @llama mwaaa\n\
               \date time * chainsol is morky\n\
               \date time @llama bye mwaaa\n\
               \date time * cppxor2arr wants to be bogs\n"
    print $ nickMsgCnt log
{-
output:
Zerock: 1
chainsol: 1
cppxor2arr: 2
letty: 1
llama: 2
uptime: 1
-}

nickMsgCnt :: String -> [(String,Int)]
nickMsgCnt = frequency . delPrefixes . nicks . msgs . slice . filterInvalid . parse
    where parse = map words . lines
          filterInvalid = filter ((>= 3) . length)
          slice = map (\x -> (x !! 2, x !! 3))
          msgs = filter condition
              where condition x = not . or $ map' x [join,quit,nickChange]
                        where map' x = map (\y -> y x)
                              join (x,_)  = x == "-->"
                              quit (x,_) = x == "<--"
                              nickChange (x,_) = x == "--"
          nicks = map nick
              where nick (x,y) = if x == "*" then y else x
          delPrefixes = map delPrefix
              where delPrefix all@(x:xs) = if x `elem` prefixes then xs else all
                        where prefixes = "+@"
          frequency = toList . fromListWith (+) . assocList
              where assocList = map (\x -> (x,1))

instance Show [(String,Int)] where
    show = unlines . map format
        where format (x,y) = x ++ ": " ++ show y