import qualified Data.Char as C

import qualified Data.List as L

import Ex5_10

maxOccurs :: Int -> Int -> (Int,Int)

maxOccurs a b =

let occ m n = if m == n then 2 else 1

in (max a b, occ a b)

maxThreeOccurs :: Int -> Int -> Int -> (Int, Int)

maxThreeOccurs a b c =

let howManyNotUnique m n p

| threeEqual m n p = 3

| threeNotEqual m n p = 1

| otherwise = 2

threeEqual a b c =

a==b && b==c

threeNotEqual a b c =

a/=b && a/=c && b/=c

maxThree a b c

| a>=b && a>=c = a

| b>=c = b

| otherwise = c

in (maxThree a b c, howManyNotUnique a b c)

orderTriple :: (Int,Int,Int) -> (Int,Int,Int)

orderTriple (f,s,t) =

let maxThree a b c

| a>=b && a>=c = a

| b>=c = b

| otherwise = c

middle x y z

| between y x z = x

| between x y z = y

| otherwise = z

between m n p = (n >= m && n <= p) || (n <= m && n >= p)

minThree a b c

| a<=b && a<=c = a

| b<=c = b

| otherwise = c

in

(minThree f s t, middle f s t, maxThree f s t)

findXaxis :: [(Int,Char)] -> (Int, Int)

findXaxis [(a,_),_,(b,_)] =

(b `div` a , 0)

type Equation = [PartOfEq]

type PartOfEq = (Int,Char)

type Coordinates = (Int, Int)

findXaxis1 :: Equation -> Coordinates

findXaxis1 [(a,_),_,(b,_)] =

(b `div` a , 0)

doubleAll :: [Int] -> [Int]

doubleAll xs = [ x*2 | x <- xs]

capitalize :: String -> String

capitalize xs = [C.toUpper x | x <- xs]

capitalizeLetters :: String -> String

capitalizeLetters xs = [C.toUpper x | x <- xs , C.isLetter x]

matches :: Int -> [Int] -> [Int]

matches n list = foldr (\x acc -> if x == n then x:acc else acc) [] list

elem' :: Int -> [Int] -> Bool

elem' x xs = (>0) . length . matches x $ xs

type Person = String

type Book = String

type Database = [(Person, Book)]

exampleBase :: Database

exampleBase = [("Alice" , "Tintin") , ("Anna" , "Little Women"),

("Alice" , "Asterix") , ("Rory" , "Tintin")]

books :: Database -> Person -> [Book]

books db prsn = [book | (person,book) <- db , person == prsn]

borrowers :: Database -> Book -> [Person]

borrowers db bk = [person | (person,book) <- db , book == bk]

numBorrowed :: Database -> Person -> Int

numBorrowed db prsn = length . books db $ prsn

isBorrowed :: Database -> Book -> Bool

isBorrowed db bk = (>0) . length . borrowers db $ bk

makeLoan :: Database -> Person -> Book -> Database

makeLoan db prsn bk = [(prsn , bk)] ++ db

returnLoan :: Database -> Person -> Book -> Database

returnLoan db prsn bk = [pair | pair <- db , pair /= (prsn , bk)]

-- refactor list of lists or make cool filter

type NewDB = [(Person , [Book])]

newBooks :: NewDB -> Person -> [Book]

newBooks db prsn = [concat $ books | (person,books) <- db , person == prsn]

romanDigit :: Char -> String

romanDigit a = toRoman . C.digitToInt $ a

toRoman :: Int -> String

toRoman n

| 0 < n && n < 4 = replicate n 'I'

| n == 4 = "IV"

| 5 < n && n < 9 = "V"++(replicate (n - 5) 'I')

| n == 9 = "IX"

| otherwise = "V"

onThreeLines :: String -> String -> String -> String

onThreeLines a b c = a++"\n"++b++"\n"++c++"\n"

onSeparateLines :: [String] -> String

onSeparateLines = concat . map (++"\n")

duplicate :: String -> Int -> String

duplicate str n

| n < 0 = ""

| n ==1 = str

| otherwise = concat . replicate n $ str

linelength = 12

strlength :: String -> Bool

strlength = (==linelength) . length

pushRight :: String -> String

pushRight str = if strlength str

then str else (concat $ replicate ((-) linelength $ length str) " ")++str

fibTable :: Int -> String

fibTable n = "kek"

fib :: Int -> Int

fib n

| n == 0 = 0

| n == 1 = 1

| otherwise = fib (n-2) + fib (n-1)

fibTest :: Int -> IO()

fibTest n =

helper n 0 ("n" ++ (pushRight $ "fib n") ++ "\n")

helper :: Int -> Int -> String -> IO()

helper n num los =

let saved = (num, fib num)

in

if num > n

then putStrLn los

else helper n (num+1) (los ++ ((show $ fst saved) ++ (pushRight . show $ snd saved) ++ "\n"))

-- 5.27