Main.hs

{-# LANGUAGE OverloadedStrings #-}

module Main where
import           Data.List
import           Data.Text     (Text)
import           Data.Text.IO  as IO
import           Prelude       hiding (drop, lenght, take)
import           System.Random

type Tasks = [[ Text ]]
type TasksWithBackup = ([ Text ], [ Text ])
type Version = [ Text ]

deleteNth n xs = take (n-1) xs ++ drop n xs

genVer :: [TasksWithBackup] -> IO ([TasksWithBackup], Version)
genVer t = do
    mapM getItem t >>= return . foldl (\(a, b) (c, d) -> (a ++ [c], b ++ d)) ([], [])
  where
    getItem :: TasksWithBackup -> IO (TasksWithBackup, Version)
    getItem (tasks, allTasks) = do
        i <- randomRIO (0, 1000) >>= return . flip mod (length tasks)
        let res = tasks !! i
        let newTasks = if (length tasks) - 1 == 0 then allTasks else (deleteNth i tasks)
        return $ ((newTasks, allTasks), [res])


generate :: Int -> [TasksWithBackup] -> IO [Version]
generate n tasks | n > 0 = do
    (newTasks, ver) <- genVer tasks
    vars <- (generate (n - 1) newTasks)
    return $ ver:vars
generate n tasks = return []


canonizeTasks :: Tasks -> [TasksWithBackup]
canonizeTasks a = map (\b -> (b, b)) a

main = do
    versions <- generate 45 $ canonizeTasks cw
    mapM_ (\(n, v) -> print n >> IO.putStrLn header >> mapM_ IO.putStrLn (concat $ zipWith (\a b -> a : [b]) exers v) >> IO.putStrLn "-------------") $ zip [1..] versions