{-
 - A collection of utility functions.
 -}
module Hmpf.Util where

import System.Random
import System.Posix.Time
import System.Posix.Types
import System.Time
import Data.Char ( toLower )


startsWith :: (Eq a) => [a] -> [a] -> Bool
_ `startsWith` [] = True
[] `startsWith` _ = False
(x:xs) `startsWith` (p:prefix) | x == p = xs `startsWith` prefix
                               | otherwise = False


time :: IO String
time = do 
  t <- (getClockTime >>= toCalendarTime)
  return . clock $ ( ctMin t + 60 * ctHour t )
{-
 putStrLn "1 abc 2 def 3 ghi"
 putStrLn "4 jkl 5 mno 6 pqr"
 putStrLn "7 stu 8 vwx 9 yz"
-}


--Converts seconds to min:sec
clock :: Int -> String
clock secs = 
 min ++ ":" ++ ss 
 where
  min = show (secs `div` 60)
  sec = show (secs `mod` 60)
  zeros = repeat '0'
  ss = reverse . take 2 . ( ++ zeros ) . reverse $ sec

--
eqIgnoreCase :: String -> String -> Bool
eqIgnoreCase str1 str2 =
 let l1 = map toLower str1
     l2 = map toLower str2
 in l1 == l2


pick :: [a] -> IO a
pick lst = do
 g <- newStdGen
 let binary = randoms g
 return . pick' binary $ lst 
 where
  pick' :: [Bool] -> [a] -> a
  pick' _ [x] = x
  pick' (b:bs) xs = case b of
   True -> pick' bs (left xs)
   False -> pick' bs (right xs)
   where
    n = (length xs) `div` 2
    left = take n
    right = drop n