module Main (main) where

import           Data.List      (genericLength)
import           Data.Maybe     (catMaybes)
import           System.Exit    (exitFailure, exitSuccess)
import           System.Process (readProcess)
import           Text.Regex     (matchRegex, mkRegex)

arguments :: [String]
arguments =
    [ "haddock"
    ]

average :: (Fractional a, Real b) => [b] -> a
average xs = realToFrac (sum xs) / genericLength xs

expected :: Fractional a => a
expected = 90

main :: IO ()
main = do
    output <- readProcess "cabal" arguments ""
    if average (match output) >= expected
        then exitSuccess
        else putStr output >> exitFailure

match :: String -> [Int]
match = fmap read . concat . catMaybes . fmap (matchRegex pattern) . lines
  where
    pattern = mkRegex "^ *([0-9]*)% "