module Exercise01 where

import Test.QuickCheck ((==>), property, Property )

{-H1.1a)-}
myPair :: Integer -> Integer -> Integer
myPair x y = 2^y*(2*x+1)-1

{-H1.1b)-}
mySnd :: Integer -> Integer
mySnd x | even x = 0
        | odd x = 1 + mySnd(div x 2)

{-H1.1c)-}
myFst :: Integer -> Integer
myFst x = div x (2^(mySnd x + 1))

{-H1.1d)-}
prop_myPair :: Integer -> Integer -> Integer -> Property
prop_myPair p x y = x>=0 && y>=0 && p>=0 ==> property( myPair x y == p )

{-H2-}
digitToEo :: Integer -> String
digitToEo 0 = "nul"
digitToEo 1 = "unu"
digitToEo 2 = "du"
digitToEo 3 = "tri"
digitToEo 4 = "kvar"
digitToEo 5 = "kvin"
digitToEo 6 = "ses"
digitToEo 7 = "sep"
digitToEo 8 = "ok"
digitToEo 9 = "nau"
digitToEo x     | x < 20 = "dek" ++ if mod x 10 /= 0 then " " ++ digitToEo (mod x 10) else ""
                | x < 100 = digitToEo (div x 10) ++ digitToEo (x - (div x 10 -1) * 10)

                | x < 200 = "cent" ++ if mod x 100 /= 0 then " " ++ digitToEo (mod x 100) else ""
                | x < 1000 = digitToEo(div x 100) ++ digitToEo (x - (div x 100 - 1) * 100)       

                | x < 2000 = "mil" ++ if mod x 1000 /= 0 then " " ++ digitToEo (mod x 1000) else ""
                | x < 1000000 = digitToEo(div x 1000) ++ " " ++ digitToEo (x - (div x 1000 - 1) * 1000)

{-WETT-}

numberToEo :: Integer -> String
numberToEo 0 = "nul"
numberToEo 1 = "unu"
numberToEo 2 = "du"
numberToEo 3 = "tri"
numberToEo 4 = "kvar"
numberToEo 5 = "kvin"
numberToEo 6 = "ses"
numberToEo 7 = "sep"
numberToEo 8 = "ok"
numberToEo 9 = "nau"
numberToEo x    | x < 20 = fstSmallString "dek" 10
                | x < 100 = secSmallString 10 ""

                | x < 200 = fstSmallString "cent" 100 
                | x < 1000 = secSmallString 100 "" 

                | x < 2000 = fstSmallString "mil" 1000 
                | x < 1000000 = secSmallString 1000 " "

                | nODmod6 /= 0 && nODmod6 <= 3 = bigString "iliono" 0
                | otherwise = bigString "iliardo" 3
                
                where 
                        n a =                     div (numberOfdigits x 0 -1 - a) 6 
                        fst3Digits a =            div x (10^(n a * 6 + a))
                        restDigits a =            x - fst3Digits a * 10^(n a * 6 + a)
                        nODmod6 =                 mod (numberOfdigits x 0) 6
                        fstSmallString name num = name ++ if mod x num /= 0 then " " ++ numberToEo (mod x num) else ""
                        secSmallString num mid =  numberToEo (div x num) ++ mid ++ numberToEo (x - (div x num -1) *num)  
                        bigString mil a =         numberToEo (fst3Digits a) ++ " " ++ 
                                                  (if n a /= 1 then numberToEo (n a) else "m") ++ mil ++ 
                                                  (if fst3Digits a == 1 then "" else "j") ++
                                                  (if restDigits a /= 0 then " "  ++ numberToEo (restDigits a) else  "")
                       
                    

numberOfdigits :: Integer -> Integer -> Integer
numberOfdigits 0 y = y 
numberOfdigits x y = numberOfdigits (div x 10) (y+1)

{-TTEW-}

test :: Integer -> IO ()
test 0 = return()
test n | n >= 0 = do
                putStrLn (numberToEo n)
                --test(n - 1)
                test (div n 10)