Phone.hs

Phone.hs

module Phone where

import Data.Char (isUpper, toLower)
import Control.Arrow
import Data.List (maximumBy)


type Digit = Char
type Presses = Int
type Key = (Digit, String)
type Keys = [(Digit, String)]

data DaPhone = DaPhone Keys

keyboard :: DaPhone
keyboard = DaPhone [('2', "abc"),
                ('3', "def"),
                ('4', "ghi"),
                ('5', "jkl"),
                ('6', "mno"),
                ('7', "pqrs"),
                ('8', "tuv"),
                ('9', "wxyz"),
                ('0', " "),
                ('#', ".,")]

numberOfKeyPresses :: Char -> String -> Presses
numberOfKeyPresses c xs = length (takeWhile (c /=) xs) + 1

keyContain :: Char -> Key -> Bool
keyContain c (_, xs) = c `elem` xs

reverseTaps :: DaPhone -> Char -> [(Digit, Presses)]
reverseTaps p@(DaPhone ks) c = if isUpper c
  then ('*', 1) : reverseTaps p (toLower c)
  else map (Control.Arrow.second (numberOfKeyPresses c)) $ filter (keyContain c) ks

cellPhonesDead :: DaPhone -> String-> [(Digit, Presses)]
cellPhonesDead keys = concatMap (reverseTaps keys)

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

mostPopularLetter :: String -> Char
mostPopularLetter = fst . maximumBy (\(_, a) (_, b) -> compare a b) . cellPhonesDead keyboard

coolestLtr :: [String] -> Char
coolestLtr = undefined

coolestWord :: [String] -> String
coolestWord = undefined

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