PhoneNumberParser

module Phone where

import Text.Trifecta
import Control.Applicative
import Data.Char

type NumberingPlanArea = Int
type Exchange = Int
type LineNumber = Int

data PhoneNumber = PhoneNumber NumberingPlanArea Exchange LineNumber deriving (Eq, Show)

parsePhone :: Parser PhoneNumber
parsePhone = do
    try $ optional $ char '1'
    optional $ token $ char '-'
    parsePhone'

parsePhone' :: Parser PhoneNumber
parsePhone' = do
    npa <- optional $ token $ between (char '(') (char ')') (token parseNumberingPlanArea)
    case npa of
      Nothing -> do
        npb <- token parseNumberingPlanArea
        parseTemp npb
      Just x -> do
        parseTemp x

parseTemp :: NumberingPlanArea -> Parser PhoneNumber
parseTemp x = do
        optional $ token $ char '-'
        exh <- token parseExchange
        optional $ token $ char '-'
        ln <- token parseLineNumber
        eof
        return $ PhoneNumber x exh ln


parsePhoneTotal :: Parser PhoneNumber
parsePhoneTotal = (try parsePhone) <|> parsePhone'

parseInd :: Parser PhoneNumber
parseInd = do
  optional $ token $ char '+'
  optional $ ((token $ char '9') >> (token $ char '1'))
  parsePhone'

parseNumberingPlanArea :: Parser NumberingPlanArea
parseNumberingPlanArea = do
  one <- digit
  two <- digit
  three <- digit
  return ((100 * (charToNum one)) + (10 * (charToNum two)) + (charToNum three))

parseExchange :: Parser Exchange
parseExchange = parseNumberingPlanArea

parseLineNumber :: Parser LineNumber
parseLineNumber = do
  one <- digit
  two <- digit
  three <- digit
  four <- digit
  return ((1000 * (charToNum one)) + (100 * (charToNum two)) + (10 * charToNum three) + (charToNum four))

charToNum :: Char -> Int
charToNum = subtract 48 . ord