import System (getArgs)
import System.Console.GetOpt
import IO

import Tuning
import Tuning.Standard
import Guitar
import Exercises

import System.Random
import Data.Array.IO
import Control.Monad

-- | Randomly shuffle a list
--   /O(N)/
shuffle :: [a] -> IO [a]
shuffle xs = do
        ar <- newArray n xs
        forM [1..n] $ \i -> do
            j <- randomRIO (i,n)
            vi <- readArray ar i
            vj <- readArray ar j
            writeArray ar j vi
            return vj
  where
    n = length xs
    newArray :: Int -> [a] -> IO (IOArray Int a)
    newArray n xs =  newListArray (1,n) xs




main = do
  args <- getArgs
  hSetBuffering stdout NoBuffering

  let guitar = Guitar standardTuning 22
  let barreForms = [formA, formA7, formAm, formAm7, formE, formE7, formEm, formEm7]
  let openForms = [formC, formC7, formG, formG7, formD, formD7, formDm, formDm7] ++ barreForms
  let barreChords = [ applyForm (tuning guitar) cf f | f <- [1..12], cf <- barreForms]
  let openChords = openB7 : [ applyForm (tuning guitar) cf 0 | cf <- openForms ]

  chrds <- shuffle $ openChords
  sqs <- shuffle $ [ (s,f) | s <- [1..6], f <- [0 .. len guitar]]

  menu [
      ("Ask me to play chords", mapM_ (playChord guitar) $ chrds),
      ("Ask me to identify chords", mapM_ (nameChord guitar) $ chrds),
      ("Ask me to identify notes", mapM_ (nameNote guitar) $ sqs)
    ]


menu :: [(String, IO ())] -> IO ()
menu exs = do
  let lu = zip (map (head . show) [1..]) exs
  let is = map fst lu

  putStrLn "\nSelect an exercise:\n"
  mapM_ (\(i, (n,a)) -> putStrLn $ i : ") " ++ n ) lu
  putStr $ "\nChoice (1-" ++ (show . length $ exs) ++ "): "
  (c:_) <- getLine

  when (not $ c `elem` is) $ menu exs

  case lookup c lu of
    Just (n, a) -> a