module Phone where

import Data.Char (ord)
import Data.List (sortBy)

data DaPhone = DaPhone

convo :: [String]
convo =
    [ "Wanna play 20 questions"
    , "Ya"
    , "U 1st haha"
    , "Lol ok. Have u ever tasted alcohol"
    , "Lol ya"
    , "Wow ur cool haha. Ur turn"
    , "Ok. Do u think I am pretty Lol"
    , "Lol ya"
    , "Just making sure rofl ur turn" ]

-- validButtons = "1234567890*#"
type Digit = Char

-- Valid presses: 1 and up
type Presses = Int

data Button = Button Digit String

-- assuming the default phone definition
-- 'a' -> [('2', 1)]
-- 'A' -> [('*', 1), ('2', 1)]
reverseTaps :: DaPhone -> Char -> [(Digit, Presses)]
reverseTaps _ c
  | c == '.' = [('#', 1)]
  | c == ',' = [('#', 2)]
  | c == '#' = [('#', 3)]
  | c == '+' = [('0', 1)]
  | c == ' ' = [('0', 2)]
  | c == '0' = [('0', 3)]
  | (ord c) >= (ord 'w') = [('9', (ord c) - (ord 'w') + 1)]
  | (ord c) >= (ord 't') = [('8', (ord c) - (ord 't') + 1)]
  | (ord c) >= (ord 'p') = [('7', (ord c) - (ord 'p') + 1)]
  | (ord c) >= (ord 'm') = [('6', (ord c) - (ord 'm') + 1)]
  | (ord c) >= (ord 'j') = [('5', (ord c) - (ord 'j') + 1)]
  | (ord c) >= (ord 'g') = [('4', (ord c) - (ord 'g') + 1)]
  | (ord c) >= (ord 'd') = [('3', (ord c) - (ord 'd') + 1)]
  | (ord c) >= (ord 'a') = [('2', (ord c) - (ord 'a') + 1)]
  | (ord c) >= (ord 'W') = [('*', 1), ('9', (ord c) - (ord 'W') + 1)]
  | (ord c) >= (ord 'T') = [('*', 1), ('8', (ord c) - (ord 'T') + 1)]
  | (ord c) >= (ord 'P') = [('*', 1), ('7', (ord c) - (ord 'P') + 1)]
  | (ord c) >= (ord 'M') = [('*', 1), ('6', (ord c) - (ord 'M') + 1)]
  | (ord c) >= (ord 'J') = [('*', 1), ('5', (ord c) - (ord 'J') + 1)]
  | (ord c) >= (ord 'G') = [('*', 1), ('4', (ord c) - (ord 'G') + 1)]
  | (ord c) >= (ord 'D') = [('*', 1), ('3', (ord c) - (ord 'D') + 1)]
  | (ord c) >= (ord 'A') = [('*', 1), ('2', (ord c) - (ord 'A') + 1)]
  | c == '9' = [('9', 5)]
  | c == '8' = [('8', 4)]
  | c == '7' = [('7', 5)]
  | c == '6' = [('6', 4)]
  | c == '5' = [('5', 4)]
  | c == '4' = [('4', 4)]
  | c == '3' = [('3', 4)]
  | c == '2' = [('2', 4)]
  | c == '1' = [('2', 1)]

cellPhonesDead :: DaPhone -> String -> [(Digit, Presses)]
cellPhonesDead dp s = concat (map (reverseTaps dp) s)

fingerTaps :: [(Digit, Presses)] -> Presses
fingerTaps = foldr f 0
    where f (_, p) acc = p + acc

mostPopularLetter :: String -> Char
mostPopularLetter c = fst $ head (sortBy (\(_, x1) (_, x2) -> compare x2 x1) $ foldr foldF [] c)
    where foldF c [] = [(c, 1)]
          foldF c ((x, n):xs)
            | c == x    = (x, n + 1) :  xs
            | otherwise = (x, n) : (foldF c xs)

coolestLtr :: [String] -> Char
coolestLtr = mostPopularLetter . concat

coolestWord :: [String] -> String
coolestWord c = fst $ head (sortBy (\(_, x1) (_, x2) -> compare x2 x1) $ foldr foldF [] (words (concat c)))
    where foldF c [] = [(c, 1)]
          foldF c ((x, n):xs)
            | c == x    = (x, n + 1) :  xs
            | otherwise = (x, n) : (foldF c xs)