module Message
  ( getMessage
  , getVarMessage
  ) where

import Data.Maybe (listToMaybe, fromMaybe)

import Text.ParserCombinators.Parsec

import Message.Key (Key)
import Message.Lang
import Message.Translations (getNonFormattedMessage)

getMessage :: Key -> String
getMessage = getVarMessage []

getVarMessage :: [String] -> Key -> String
getVarMessage values key =
  replaceParts values (getParts (getNonFormattedMessage French key))

replaceParts :: [String] -> [Part] -> String
replaceParts values = concatMap (replacePart values)

replacePart :: [String] -> Part -> String
replacePart _ (Str str) = str
replacePart values (Num n) =
  fromMaybe ("{" ++ show n ++ "}") . listToMaybe . drop (n - 1) $ values

data Part =
  Num Int
  | Str String

getParts :: String -> [Part]
getParts str =
  case parse partsParser "" str of
    Right parts -> parts
    Left _ -> []

partsParser :: Parser [Part]
partsParser = many partParser

partParser :: Parser Part
partParser =
  (do _ <- string "{"; n <- read <$> many1 digit; _ <- string "}"; return (Num n))
  <|> (do str <- many1 (noneOf "{"); return (Str str))